Dissertations / Theses on the topic 'Temporale, region'

Es preveu que la Gestió del Trànsit Aeri (ATM) canviï dràsticament. Per a satisfer la creixent demanda d’ús de l’espai aèri, s’esperen canvis dràstics en la present Gestió del Trànsit Aeri (ATM). Per l’horitzó de temps estratègic, que s’estén fins al 2050, Existeixen 2 línies de pensament que agrupen les diferents alternatives per a un horitzó de temps estratègic, que s’estén fins al 2050. Una es basa en un moviment cap a l’espai aeri no controlat i el concepte del vol lliure. L’altre busca moure’s cap a la direcció oposada, la de l’espai aeri totalment automatitzat i controlat. Més enllà de les seves diferències conceptuals, ambdues visions manifesten alguns components comuns. La necessitat d’una detecció i resolució de conflictes tàctica (CD&R) automatitzada en ruta és una d’elles. Tot i que el tema de CD&R ha estat investigat a fons en les últimes tres dècades, existeixen diferents aspectes que no han estat tractats. En particular, les solucions proposades no mostren cert nivell de resiliència, no proporcionen una identificació completa del tràfic circumdant que podria veure’s afectat per la resolució del conflicte original, no permeten que els usuaris de l’espai aèri participin en la Resolució de Conflictes (CR) de manera realista (per aconseguir resolucions eficients), i no proporcionen els límits de temps de maniobra dins dels quals es poden aconseguir resolucions factibles. Aquest treball aborda els problemes anteriors de la següent manera. Es proposa l’ús de regions espacio-temporals en lloc de trajectòries úniques per aconseguir cert nivell de resiliència en la CR. A través del mètode proposat de “coll d’ampolla”, es quantifica el nivell de resiliència de les regions. L’ “ecosistema aeri”, la construcció formal que serveix per aconseguir la identificació completa del tràfic circumdant rellevant, es defineix formalment per dotar al CR de la propietat de sistema completEs realitza una anàlisi del tràfic històric i projectat per a identificar la dimensió dels ecosistemes aeris formats. La detecció de conflictes per parelles s’utilitza per construir un ecosistema aeri complet. Per a tractar casos en els quals coexisteixen diferents conflictes parells en el temps amb estreta dependencia espacial, s’amplia el concepte “d’ecosistema aeri” i es defineix l’ “ecosistema compost”. A més, es proposen algunes estratègies per a mitigar la dependència entre els conflictes per parelles dins de l’ecosistema compost. Es realitza una anàlisis del tràfic històric i sintètic per a identificar els ecosistemes compostos que es formen i provar l’efectivitat de les estratègies de mitigació proposades. S’adopta un mecanisme de negociació automatitzat, a través del qual els usuaris de l’espai aèri poden participar activament en el procés de CR. El mecanisme proposat és descentralitzat, proporciona la integritat del procés d’identificació i ofereix cert nivell de resiliència. D’aquesta manera, els usuaris de l’espai aèri poden participar en el CR amb el propòsit d’augmentar l’eficiència sense revelar les seves preferències respecte dels seus costos i estratègies. El mecanisme de negociació automatitzat s’enriqueix amb un enfocament inicial per a identificar els límits temporals del marc de resolució de conflictes per parelles de l’aeronau delegada. Aquesta informació s’utilitza per a determinar el límit temporal per al procediment de negociació automatitzat.
Para hacer frente a la creciente demanda de uso del espacio aéreo, se esperan cambios drásticos en la presente Gestión del Tránsito Aéreo (ATM). Existen 2 líneas de pensamiento que agrupan las diferentes alternativas para un horizonte de tiempo estratégico, que se extiende hasta 2050. Una se basa en un movimiento hacia el espacio aéreo no controlado y el concepto de vuelo libre. La otra busca moverse hacia la dirección opuesta, la del espacio aéreo totalmente automatizado y controlado. Más allá de sus diferencias conceptuales, ambas visiones manifiestan algunos componentes comunes. La necesidad de una detección y resolución de conflictos táctica (CD&R) automatizada en ruta es una de ellas. Aunque el tema de CD&R ha sido investigado a fondo en las últimas tres décadas, existen varios aspectos que no han sido tratados. En particular, las soluciones propuestas no exhiben cierto nivel de resiliencia, no proporcionan una identificación completa del tráfico circundante que podría verse afectado por la resolución del conflicto original, no permiten que los usuarios del espacio aéreo participen en la Resolución de Conflictos (CR) de manera realista (para lograr resoluciones eficientes), y no proporcionan los límites de tiempo de maniobra dentro de los cuales se pueden lograr resoluciones factibles. Este trabajo aborda los problemas anteriores de la siguiente manera. Se propone el uso de regiones espacio-temporales en lugar de trayectorias únicas para lograr cierto nivel de resiliencia en la CR. A través del método propuesto de “cuello de botella”, se cuantifica el nivel de resiliencia de las regiones. El “ecosistema aéreo”, la construcción formal que sirve para lograr la identificación completa del tráfico circundante relevante, se define formalmente, para dotar al CR de la propiedad de sistema completo. Se realiza un análisis del tráfico histórico y proyectado para identificar el tamaño de los ecosistemas aéreos formados. La detección de conflictos por parejas se utiliza para construir un ecosistema aéreo completo. Para tratar casos en los que coexisten varios conflictos pares en el tiempo con estrecha dependencia espacial, se amplía el concepto de “ecosistema aéreo” y se define el “ecosistema compuesto”. Además, se proponen algunas estrategias para mitigar la dependencia entre los conflictos por parejas dentro del ecosistema compuesto. Se realiza un análisis del tráfico histórico y sintético para identificar los ecosistemas compuestos que se forman y probar la efectividad de las estrategias de mitigación propuestas. Se adopta un mecanismo de negociación automatizado, a través del cual los usuarios del espacio aéreo pueden participar activamente en el proceso de CR. El mecanismo propuesto es descentralizado, proporciona la integridad del proceso de identificación y ofrece cierto nivel de resiliencia. De esta manera, los usuarios pueden participar en el CR con el propósito de aumentar la eficiencia sin revelar sus preferencias con respecto a sus costes y estrategias. El mecanismo de negociación automatizado se enriquece con un enfoque inicial para identificar los límites temporales del marco de resolución de conflictos por parejas de la aeronave delegada. Esta información se utiliza para determinar el límite temporal para el procedimiento de negociación automatizado.
Air Traffic Management (ATM) is envisioned to change drastically in order to accommodate the increasing demand. For the strategic time horizon, that spans up to 2050, two lines of thoughts are presented. One of them supports a move towards non-controlled airspace and the concept of free flight. The other one seeks to move towards the opposite direction, that of fully automated, controlled airspace. Beyond their conceptual differences, both visions manifest some common components. The necessity for automatic tactical, en-route Conflict Detection & Resolution (CD&R) is one of them. Although the topic of CD&R has been heavily investigated the last three decades, several issues have not been treated by the literature. In particular, the proposed solvers do not exhibit some level of resilience, they do not provide a complete identification of the surrounding traffic that might be affected by the resolution of the original conflict, they do not allow airspace users to be involved in the Conflict Resolution (CR) in a realistic way in order to achieve efficient resolutions, and they do not provide the maneuver time limits within which feasible resolutions can be achieved. This work addresses the above issues in the following manner. The use of spatio-temporal regions instead of unique trajectories is proposed in order to achieve some level of resilience in the CR. Through the proposed “bottleneck” method, the regions’ level of resilience is quantified. The so called “aerial ecosystem”, the formal construct that serves to achieve complete identification of the relevant surrounding traffic, is formally defined in order to extend the CR with the completeness property. An analysis of historical and projected traffic in order to identify the size of the formed aerial ecosystems is performed. Pairwise conflict detection is used to construct a full aerial ecosystem. In order to treat cases when several pairwise conflicts co-exist in time with tight spatial bounds, the “aerial ecosystem” concept is extended and the “compound ecosystem” is defined. Moreover, some strategies to mitigate the dependence between the pairwise conflicts within the compound ecosystem are proposed. An analysis of historical and synthetic traffic is performed in order to identify the compound ecosystems that are formed and test the effectivity of the proposed mitigation strategies. An automated negotiation mechanism, through which airspace users can actively participate in the CR process is adopted. The proposed mechanism is decentralized, provides completeness of the identification process, and offers some level of resilience. In such a manner, airlines can participate in the CR with the purpose of increasing efficiency without revealing their preferences regarding their costs and strategies. The automated negotiation mechanism is enriched by an initial approach to identify the temporal fences of the delegated aircraft pairwise conflict resolution framework. This information is used to determine the deadline for the automated negotiation procedure.

This work discusses region-based representations for image and video sequence segmentation. It presents effective image segmentation techniques and demonstrates how these techniques may be integrated into algorithms that solve some of the motion segmentation problems. The region-based representation offers a way to perform a first level of abstraction and to reduce the number of elements to process with respect to the classical pixel-based representation. Motion segmentation is a fundamental technique for the analysis and the understanding of image sequences of real scenes. Motion segmentation 'describes' the sequence as sets of pixels moving coherently across one sequence with associated motions. This description is essential to the identification of the objects in the scene and to a more efficient manipulation of video sequences. This thesis presents a hybrid framework based on the combination of spatial and motion information for the segmentation of moving objects in image sequences accordingly with their motion. We formulate the problem as graph labelling over a region moving graph where nodes correspond coherently to moving atomic regions. This is a flexible high-level representation which individualizes moving independent objects. Starting from an over-segmentation of the image, the objects are formed by merging neighbouring regions together based on their mutual spatial and temporal similarity, taking spatial and motion information into account with the emphasis being on the second. Final segmentation is obtained by a spectral-based graph cuts approach. The initial phase for the moving object segmentation aims to reduce image noise without destroying the topological structure of the objects by anisotropic bilateral filtering. An initial spatial partition into a set of homogeneous regions is obtained by the watershed transform. Motion vector of each region is estimated by a variational approach. Next a region moving graph is constructed by a combination of normalized similarity between regions where mean intensity of the regions, gradient magnitude between regions, and motion information of the regions are considered. The motion similarity measure among regions is based on human perceptual characteristics. Finally, a spectral-based graph cut approach clusters and labels each moving region. The motion segmentation approach is based on a static image segmentation method proposed by the author of this dissertation. The main idea is to use atomic regions to guide a segmentation using the intensity and the gradient information through a similarity graph-based approach. This method produces simpler segmentations, less over-segmented and compares favourably with the state-of-the-art methods. To evaluate the segmentation results a new evaluation metric is proposed, which takes into attention the way humans perceive visual information. By incorporating spatial and motion information simultaneously in a region-based framework, we can visually obtain meaningful segmentation results. Experimental results of the proposed technique performance are given for different image sequences with or without camera motion and for still images. In the last case a comparison with the state-of-the-art approaches is made.

Temporal lobe epilepsy (TLE) is among the most common chronic seizure disorders, accounting for approximately one-fourth of all cases of epilepsy. Although hippocampal sclerosis is the most common pattern of damage in TLE, there is electrophysiological and neuropathological evidence in both humans and animal models of this condition for the involvement of the parahippocampal region.
In clinical practice, the investigation and treatment of patients with epilepsy has been revolutionized by the advent of MRI, which has been demonstrated to be a reliable and accurate indicator of pathologic findings underlying epilepsy. Advances in image acquisition and processing techniques combined with detailed descriptions of anatomy and cytoarchitectonic borders of parahippocampal structures on histologic sections have created the basis for precise determination of the boundaries of these cortical areas on MRI. This dissertation presents a series of MRI studies aimed at assessing volume changes in vivo of the parahippocampal region, and further elucidating its role in the pathogenesis of TLE.
To accomplish this we developed a standardized MRI protocol to measure the volume of the parahippocampal region structures in vivo. In agreement with previous neuropathological studies (Meencke and Veith, 1991), our results showed that damage to the mesial temporal lobe involves not only the hippocampus and the amygdala, but also the parahippocampal region structures in patients with intractable TLE. Within the parahippocampal region, the entorhinal cortex was the most affected structure. We observed that the atrophy was more severe in the anterior portion of the mesial temporal lobe involving mostly the hippocampal head and body as well as the EC. This pattern of atrophy, characterized by an antero-posterior gradient of pathology, may be explained by a disruption of entorhinal-hippocampal connections.
To evaluate the clinical role of entorhinal cortex volumetry we studied groups of TLE patients with hippocampal atrophy and those with normal hippocampal volumes as well as patients with extra-temporal lobe epilepsy.
Entorhinal cortex volumetry could provide correct lateralization of the seizure focus in 73% of TLE patients with hippocampal atrophy. Entorhinal cortex atrophy seems to be specific to TLE, since we found no atrophy in other forms of epilepsy, including frontal lobe and primary generalized epilepsy. We subsequently demonstrated that entorhinal cortex atrophy ipsilateral to the seizure focus can be the only MRI sign of mesial temporal damage in 64% of patients with normal hippocampal volumes.

Thesis (M.S. in Meteorology and Physical Oceanography)--Naval Postgraduate School, September 2006.
Thesis Advisor(s): Qing Wang, Wendell A. Nuss. "September 2006." Includes bibliographical references (p. 61-62). Also available in print.

In video transmission at low bit rates the challenge is to compress the video with a minimal reduction of the percieved quality. The compression can be adapted to knowledge of which regions in the video sequence are of most interest to the viewer. Region of interest (ROI) video coding uses this information to control the allocation of bits to the background and the ROI. The aim is to increase the quality in the ROI at the expense of the quality in the background. In order for this to occur the typical content of an ROI for a particular application is firstly determined and the actual detection is performed based on this information. The allocation of bits can then be controlled based on the result of the detection.

In this licenciate thesis existing methods to control bit allocation in ROI video coding are investigated. In particular pre-processing methods that are applied independently of the codec or standard. This makes it possible to apply the method directly to the video sequence without modifications to the codec. Three filters are proposed in this thesis based on previous approaches. The spatial filter that only modifies the background within a single frame and the temporal filter that uses information from the previous frame. These two filters are also combined into a spatio-temporal filter. The abilities of these filters to reduce the number of bits necessary to encode the background and to successfully re-allocate these to the ROI are investigated. In addition the computational compexities of the algorithms are analysed.

The theoretical analysis is verified by quantitative tests. These include measuring the quality using both the PSNR of the ROI and the border of the background, as well as subjective tests with human test subjects and an analysis of motion vector statistics.

The qualitative analysis shows that the spatio-temporal filter has a better coding efficiency than the other filters and it successfully re-allocates the bits from the foreground to the background. The spatio-temporal filter gives an improvement in average PSNR in the ROI of more than 1.32 dB or a reduction in bitrate of 31 % compared to the encoding of the original sequence. This result is similar to or slightly better than the spatial filter. However, the spatio-temporal filter has a better performance, since its computational complexity is lower than that of the spatial filter.

Mining spatio-temporal reachable regions aims to find a set of road segments from massive trajectory data, that are reachable from a user-specified location and within a given temporal period. Accurately extracting such spatio-temporal reachable area is vital in many urban applications, e.g., (i) location-based recommendation, (ii) location-based advertising, and (iii) business coverage analysis. The traditional approach of answering such queries essentially performs a distance-based range query over the given road network, which have two main drawbacks: (i) it only works with the physical travel distances, where the users usually care more about dynamic traveling time, and (ii) it gives the same result regardless of the querying time, where the reachable area could vary significantly with different traffic conditions. Motivated by these observations, in this thesis, we propose a data- driven approach to formulate the problem as mining actual reachable region based on real historical trajectory dataset. The main challenge in our approach is the system efficiency, as verifying the reachability over the massive trajectories involves huge amount of disk I/Os. In this thesis, we develop two indexing structures: 1) spatio-temporal index (ST-Index) and 2) connection index (Con-Index) to reduce redundant trajectory data access operations. We also propose a novel query processing algorithm with: 1) maximum bounding region search, which directly extracts a small searching region from the index structure and 2) trace back search, which refines the search results from the previous step to find the final query result. Moreover, our system can also efficiently answer the spatio-temporal reachability query with multiple query locations by skipping the overlapped area search. We evaluate our system extensively using a large-scale real taxi trajectory data in Shenzhen, China, where results demonstrate that the proposed algorithms can reduce 50%-90% running time over baseline algorithms.

Aggregate operations are valuable tools for data analysis in databases. For example, the traditional aggregates like sum, average, count, min and max enable powerful analysis over data in relational databases. Set operations like union, intersection and difference can be used to find aggregate values on spatial, temporal and spatiotemporal data. They take a set of regions, either static or moving, and return a single region. Though there were existing structures to find an aggregate value on spatiotemporal data, they are not efficient to query aggregates on moving regions. This paper proposes a structure that we can use to find different types of aggregates on moving regions.

As precipitation is a very important parameter of climate and hydrology, exploring spatial and temporal distribution and variation of this variable can give an idea about climate conditions and water resources in the future. Therefore accurate mapping of the temporal and spatial distributions of precipitation is important for many applications in hydrology, climatology, agronomy, ecology and other environmental sciences. In this thesis, spatiotemporal distributions and variations of total annual, seasonal and monthly precipitation of the Eastern Mediterranean (EM) are analysed. The Eastern Mediterranean is one of the most prominent hot spot of climate change in the world further; extreme climatic events such as drought are expected to become more frequent and intense in this region. Main data source is instrumental data of monthly and daily precipitation at 103 and 70 meteorological stations, respectively. Spatial coherence analysis, coefficient of variation (CV), rainfall seasonality index (SI), incomplete gamma distribution and precipitation concentration index (PCI) are applied to evaluate the seasonality and variability of annual, seasonal and monthly precipitation amounts and their distribution. Daily precipitation concentration index (CI) is used as an important index for specifying daily rainfall characteristics. Additionally, rainfall entropy is also calculated for monthly and daily data for finding the most suitable probability distribution under the available information. High to moderate irregularity and rainfall concentration are the two very characteristic features of rainfall in the EM. Highest values of daily CI are detected in the southern parts of the EM. Distribution of annual precipitation CI trends indicate a statistically significant increase in the northern and northwestern regions of the EM. Four meteorological drought indices (DIs) are calculated at monthly time scale, the Standardized Precipitation Index (SPI), the Modified China Z Index (MCZI), the Statistical Z -scores and the Rainfall Decile based Drought Index (DI) while the Effective Drought Index (EDI) is calculated at daily time scale. All selected DIs with multiple time steps are applied to compute the severity for five time steps of 3, 6, 9, 12 and 24-month, and compared with each other and EDI. The most significant factor affecting the spatial accuracy of drought indices is seasonality. Study of DIs shows that the DIs are highly correlated at same time steps and can alternatively be used and the DIs computed for 6 and 9-month time step are best correlated with each other. SPI and MCZI are more consistent in detecting droughts for different time steps. EDI is found to be best correlated with other DIs when considering all time steps. The investigation shows that the use of an appropriate time step is as important as the type of DI used to identify drought severities. Principal Component Analysis (PCA) is employed and reveals the main modes and spatiotemporal variability of seasonal and annual precipitation and droughts over the EM. The preliminary analysis indicated tendencies towards a drier climate due to a statistically significant decrease in annual precipitation over the EM. The analysis of indicators of extreme events reveals a much more complex transformation of the climatic pattern with strong regional and seasonal variation. The results demonstrated that an extreme wet spells in the EM will shorten in all seasons, except autumn. Precipitation extremes are projected to become more pronounced in the northern parts of the EM than in southern ones and tend to be more significant during autumn. Extreme and heavy precipitation events showed a statistically significant decrease in whole parts of the EM and in the southern ones, respectively with a significant decreasing in total precipitation amount. A significant increase in daily intense precipitation events in the northern parts of the EM. In addition, climate extreme indices recommended by the joint World Meteorological Organization (CCL/CLIVAR/JCOMM) Expert Team on Climate Change Detection and Indices (ETCCDI) are also calculated for daily precipitation data. Finally, Mann- Kendall test, cumulative sum chart (CUSUM), regime shift index (RSI) calculated by a sequential algorithm are applied for detecting the shifts in the means of seasonal and annual precipitations. Mann-Kendall test and the linear slopes of trends are calculated using Sen’s slope estimator to determine the trend magnitude for SPI, CI, extreme precipitation indices, dry and drought periods. The highest decreasing of rainfall amounts is found in spring and winter and these seasons are the overall driving factor of trends in annual precipitation. Overall results of the trend analysis on the reconstructed shows that over last 52 years the drought events are more sever and frequent after 1990s over the EM which reflects negative effects on socio- economic sectors as well as water resources in this region. The findings of this study could be used or extended in further studies in the future to gain insights regarding the precipitation variability, drought patterns and extreme events over the domain of the EM.
La precipitación es una variable muy importante del clima y la hidrología. La exploración de su distribución espacial y temporal y su variación puede dar una idea acerca de las condiciones del clima y los recursos hídricos en un futuro. Por lo tanto, el mapeo amento? Preciso de la distribución temporal y espacial resulta importante para muchas aplicaciones ya sea en hidrología, climatología, agronomía, ecología, y otras ciencias ambientales. En esta tesis, se analizan las distribuciones espacio-temporales y variaciones de la precipitación total anual, estacional y mensual en el Mediterráneo Oriental (MO). El Mediterráneo Oriental es uno de los puntos calientes más prominentes al cambio climático por lo que espera que los eventos climáticos extremos, como las sequías, sean más frecuentes e intensas en esta región. La principal fuente de datos es instrumental, de estaciones meteorológicas. Con un total de 103 a escala mensual y 70 a escala diaria. El análisis espacial de coherencia, el coeficiente de variación (CV), el índice de estacionalidad y precipitaciones (SI), la distribución gamma incompleta y el índice de concentración de la precipitación (PCI), se aplican para evaluar la estacionalidad y la variabilidad de las cantidades de precipitación anual, estacional y mensual y su distribución. El índice de concentración de la precipitación diaria (CI) se utiliza como índice imprescindible para la especificación de las características diarias de lluvia. Además, la entropía de las precipitaciones también se calcula para los datos mensuales y diarios con el fin de encontrar la distribución de probabilidad más adecuada de la información disponible. Una irregularidad moderada y la concentración de las precipitaciones son los dos rasgos más característicos de las precipitaciones en la EM. Los valores más altos de CI diario se detectan en las partes meridionales de la EM. La distribución de las tendencias anuales de (CI precipitación) indican un aumento estadísticamente significativo en las regiones del norte y noroeste de la EM. Cuatro índices de sequía meteorológica (DIs) se calculan a escala de tiempo mensual, el Índice de Precipitación Estandarizada (SPI), la modificación de China Índice Z (MCZI), los -scores Z estadísticos y el Índice de Sequía basada precipitaciones débil (DI), mientras que la sequía Efectiva Índice (EDI) se calcula en la escala de tiempo diario. Todos los DIs seleccionados con múltiples pasos de tiempo se aplican para calcular la gravedad durante cinco pasos de tiempo de 3, 6, 9, 12 y 24 meses, y se compararon entre sí y con EDI. El factor más importante que afecta a la precisión espacial de índices de sequía es la estacionalidad. El estudio de DIs muestra que los DI están altamente correlacionados en mismos pasos de tiempo y de forma alternativa se pueden utilizar, y los DI calculados para los pasos de tiempo de 6 y 9 meses son los más correlacionados entre sí. SPI y MCZI son más consistentes en la detección de las sequías para los diferentes pasos de tiempo. El EDI tiene la mejor correlación con otros DIS en diferentes pasos de tiempo. La investigación muestra que el uso de un paso de tiempo apropiado es tan importante como el tipo de DIs utilizado para identificar severidades de sequía. Los análisis de los Componentes Principales (PCA) se emplean y revelan los principales modos de la variabilidad espacio-temporal de la precipitación estacional, anual y también los episodios de las sequías del MO. El análisis preliminar indica tendencias hacia un clima más seco debido a una disminución estadísticamente significativa en la precipitación anual durante el MO. El análisis de los indicadores de los fenómenos extremos revela una transformación mucho más compleja de la pauta climática con fuerte variación regional y estacional. Los resultados demostraron que episodios de lluvia extrema en el EM se acortarán en todas las estaciones, excepto otoño. Las precipitaciones extremas se proyectan a ser más pronunciadas en la parte norte de la MO que en las del sur, y tienden a ser más significativas en el otoño. Eventos extremos de precipitación mostraron una disminución estadísticamente significativa en partes enteras de la EM, y en las del sur, respectivamente, con una significativa disminución en la cantidad total de precipitación y un aumento significativo de las precipitaciones intensas diarias en la parte norte de la EM. Además, los índices de extremos climáticos recomendados por la Organización Meteorológica Mundial (CCL / CLIVAR / CMOMM), con un equipo de expertos sobre detección del cambio climático e índices (ETCCDI), también se calculan para los datos de precipitación diaria. Por último, la prueba de Mann-Kendall, carta suma acumulativa (CUSUM), el índice de cambio de régimen (RSI), calculado mediante un algoritmo secuencial fueron aplicadas para detectar los cambios en el medio de las precipitaciones estacionales y anuales. La prueba de Mann-Kendall y las pistas lineales de las tendencias se calculan utilizando la pendiente estimadora de Sen para determinar la magnitud tendencia de SPI, CI, los índices de precipitación extrema, los períodos secos y sequías. La mayor disminución de las cantidades de lluvia se encuentra en la primavera e invierno. Estas estaciones son el factor de conducción general de las tendencias de la precipitación anual. Y los resultados generales del análisis de las tendencias en los programas reconstruidos indican que durante los últimos 52 años las sequías son más frecuentes después el año 1990 sobre el MO, los cuales reflejan los efectos negativos sobre los sectores socioeconómicos, así como los recursos hídricos en esta región. Los hallazgos de este estudio podrían utilizarse o ampliarse en otros estudios en el futuro para obtener información con respecto a la variabilidad de la precipitación, patrones de sequía y fenómenos extremos sobre el dominio del MO.

Thesis (M. S.)--Earth and Atmospheric Sciences, Georgia Institute of Technology, 2010.
Committee Chair: Peter J. Webster; Committee Member: Judith A. Curry; Committee Member: Robert X. Black. Part of the SMARTech Electronic Thesis and Dissertation Collection.

Thesis (M.A.)--University of North Carolina at Chapel Hill, 2009.
Title from electronic title page (viewed Oct. 5, 2009). "... in partial fulfillment of the requirements for the degree of Master of Arts in the Department of Geography." Discipline: Geography; Department/School: Geography.

Spatio-temporal reasoning is the area of automated reasoning about space and time and is important in the field of robotics. It is desirable for an autonomous robot to have the ability to reason about both time and space. ST0 is a logic that allows for such reasoning by, among other things, defining a formalism used to describe the relationship between spatial regions and a calculus that allows for deducing further information regarding such spatial relations. An extension of ST0 is ST1 that can be used to describe the relationship between spatial entities across time-points (inter-temporal relations) while ST0 is constrained to doing so within a single time-point. This allows for a better ability of expressing how spatial entities change over time. A major obstacle in using ST1 in practise however, is the fact that any observations made regarding spatial relations between regions is constrained to the time-point in which the observation was made, so we are unable to observe inter-temporal relations. Further complicating things is the fact that deducing such inter-temporal relations is not possible without a frame of reference. This thesis examines one method of overcoming these problems by considering the concept of rigid regions which are assumed to always be unchanging and using them as the frame of reference, or as landmarks. The effectiveness of this method is studied by conducting experiments where a comparison is made between various landmark ratios with respect to the total number of regions under consideration. Results show that when a high degree of intra-temporal relations are fully or partially known, increasing the number of landmark regions will reduce the percentage of inter-temporal relations to be completely unknown. Despite this, very few inter-temporal relations can be fully determined even with a high ratio of landmark regions.

Children with developmental dyslexia have difficulty learning to read. These children may also have deficits in temporal processing, which is the perception and integration of rapidly presented stimuli. Behavioural research indicates a link between reading and temporal processing ability; however, the cortical relationship between these two skills has not been established. This thesis examined whether tasks of reading and temporal processing activate similar cortical regions in children with average reading ability and in children with dyslexia. Using functional magnetic resonance imaging (fMRI), activity for two reading tasks (phonological and orthographic) and two temporal processing tasks (dichotic pitch and global motion perception) was assessed. Three regions of interest were established in each participant: the lateral occipital cortex (LOC) and areas engaged by dichotic pitch and global motion tasks. Results demonstrated that both groups had increased activity in bilateral LOC during reading. In average readers, left LOC was more active than right regions during the phonological task, while dyslexic readers showed equivalent activity between left and right LOC for both reading tasks. The dichotic pitch regions did not show any evidence of activation during reading in either group. However, children with dyslexia exhibited significant activity in right global motion regions during the phonological task, but only on the difficult word condition. Average readers did not illustrate activation in global motion areas during reading. The current results suggest that LOC is involved with the reading process and children with dyslexia may have a deficit in left LOC. It was hypothesized that dyslexic readers may have increased attentional processing and recruitment from additional cortical regions during difficult tasks, which may explain the similar activity between global motion and phonological reading. Since there were no similar regions between dichotic pitch and reading, this suggests that these may not be directly related through cortical activity. The current results provide novel evidence that reading and visual temporal processing may involve some of the same cortical areas, at least in children with dyslexia. Future research will investigate links between reading and temporal processing in younger children and will examine differences in white matter connectivity.

La tesi que es presenta té com a objecte d’estudi el transport del sediment dissolt a les aigües superficials del riu Anoia. Es tracta d’una conca d’escala mitjana, amb 926 km2 de superfície, situada al nord-est de la península Ibèrica. És afluent del riu Llobregat, i es troba en una regió de clima mediterrani i de litologia molt variada, essent en general més sedimentària a la capçalera, calcària i granítica al centre, i abundant en margues i gresos al final del curs. El treball de camp comportà un mostreig quinzenal d’aigües superficials a cinc punts repartits de la conca, durant els anys hidrològics 2011-12 i 2012-13. Al final del període s’obtingué un total de 240 mostres, de les quals s’analitzaren diferents paràmetres fisicoquímics. Al camp es mesuraren el cabal instantani (Qi) i la temperatura (T) del riu a cada secció. Les mesures del pH, la conductivitat elèctrica (CE), el pes del sediment sediment en suspensió (SS), el contingut en sals (NaCl) i les concentracions de bicarbonats (HCO3-), clor (Cl-), nitrats (NO3-), nitrits (NO2-) i fosfats (PO43-) es feren al laboratori de Geografia Física de la Universitat de Barcelona. Els ions de calci (Ca2+), sodi (Na+), magnesi (Mg2+), potassi (K+), sulfats (SO42-), manganès (Mn2+), ferro (Fe2+), silici (Si-), zinc (Zn2+), alumini (Al3+) i fòsfor total (P3-) es dugueren a analitzar als Centres Científics i Tecnològics de la UB mitjançant la tècnica ICP-MS. Les dades permeten distingir diferents tipus d’aigua en cada secció, confirmar la hipòtesi que el grau de mineralització disminueix en augmentar l’aportació, trobar relacions entre paràmetres mitjançant anàlisis estadístiques simples i multivariants, determinar la qualitat ecològica i la potabilitat de la mateixa, i finalment estimar el pes total de la càrrega dissolta transportada per anys. Els resultats obtinguts posen de manifest l’elevada salinitat natural del riu i han permès detectar la gran variabilitat existent entre el total de sediment dissolt transportat a cada punt, així com les variacions registrades dels paràmetres fisicoquímics en els mateixos indrets. Malgrat que el total de càrrega dissolta en aigua és major a la capçalera que a qualsevol altre lloc, amb uns valors mitjans de 1576 mg·l-1, a la desembocadura la concentració de soluts és de 1076 mg·l-1. El total de càrrega dissolta que es vessa al Llobregat ha resultat, de mitjana, de 33000 tones per any. L’efecte del cabal en la dilució dels minerals, la importància del clima i la litologia, així com els usos del sòl, són factors que s’han detectat a tots els punts de mostreig, en graus diferents. A la capçalera, el substrat és el factor més decisiu en la composició química de les aigües, donada la seva erosivitat. A les rieres, l’aqüífer de Carme-Capellades del qual sorgeixen les aigües els confereix unes propietats hidroquímiques específiques, que responen al cabal només en episodis de crescuda importants. A St. Sadurní i a Martorell la composició de les aigües és més sensible al cabal que els altres punts, però estan més afectades per l’impacte antròpic.
The thesis presented aims to study the transport of dissolved solids in stream water of the Anoia river. It is a medium-sized basin with 926 km2 of surface, located in the northeast of the Iberian Peninsula. It is a tributary of the Llobregat river, and it is found in a region of Mediterranean climate and varied lithology. The fieldwork involved biweekly sampling of stream water in five points distributed throughout the basin during the hydrological years 2011-12 and 2012-13. At the end of the period it was obtained a total of 240 samples, from which different physicochemical parameters were analyzed. In the field it was measured the instantaneous discharge (Qi) and temperature (T) in each section of the river. The measurements of pH, electrical conductivity (CE), the weight of the suspended sediment (SS), salt content (NaCl) and the concentrations of bicarbonates (HCO3-), chlorine (Cl-), nitrates (NO3-), nitrites (NO2-) and phosphates (PO43-) were done at the laboratory of Physical Geography of the University of Barcelona. The calcium ions (Ca2+), sodium (Na+), magnesium (Mg2+), potassium (K+), sulfates (SO42-), manganese (Mn2+), iron (Fe2+), silicon (Si-), zinc (Zn2+), aluminum (Al3+) and total phosphorus (P3-) were analyzed at the Scientific and Technical Centers of the UB by ICP-MS technique. The data set allow to distinguish different types of water in each section, confirm the hypothesis that the degree of mineralization decreases with increasing flow, find relationships between parameters using simple and multivariate statistical analyzes, determine the ecological quality and drinkability of it, and then estimate the total weight of the dissolved loads transported up for years. The results show the high natural salinity of the river and have allowed to detect the great variability between the total dissolved solids transported at every point, while finding temporal variations of physicochemical parameters recorded in the same places. Although the total solutes concentration in water is greater at the headwaters than elsewhere, with average values of 1576 mg·l-1, at the outlet the mean mineralization is 1076 mg·l-1. The total dissolved loads transferred to the Llobregat river has been an average of 33000 tons per year.

Central New York is located in one of the snowiest regions in the United States, with the city of Syracuse, New York the snowiest metropolis in the nation. Snowfall in the region generally begins in mid-November and lasts until late-March. Snow accumulation occurs from a multitude of conditions: frontal systems, mid-latitude cyclones, Nor'easters, and most notably lake-effect storms. Lake effect snowfall (LES) is a difficult parameter to forecast due to the isolated and highly variable nature of the storm. Consequently, studies have attempted to determine changes in snowfall for lake-effect dominated regions. Annual snowfall patterns are of particular concern as seasonal snowfall totals are vital for water resources, winter businesses, agriculture, government and state agencies, and much more. Through the use of snowfall, temperature, precipitation, and location data from the National Weather Service's Cooperative Observer Program (COOP), spatial and temporal changes in snowfall for Central New York were determined. In order to determine climatic changes in snowfall, statistical analyses were performed (i.e. least squares estimation, correlations, principal component analyses, etc.) and spatial maps analyzed. Once snowfall trends were determined, factors influencing the trends were examined. Long-term snowfall trends for CNY were positive for original stations (~0.46 +/- 0.20 in. yr-1) and homogenously filtered stations (0.23 +/- 0.20 in. yr-1). However, snowfall trends for shorter time-increments within the long-term period were not consistent, as positive, negative, and neutral trends were calculated. Regional differences in snowfall trends were observed for CNY as typical lake-effect areas (northern counties, the Tug Hill Plateau and the Southern Hills) experienced larger snowfall trends than areas less dominated by LES. Typical lake-effect months (December - February) experienced the greatest snowfall trend in CNY compared to other winter months. The influence of teleconnections on seasonal snowfall in CNY was not pronounced; however, there was a slight significant (5%) correlation (< 0.35) with the Atlantic Multidecadal Oscillation. It was not clear if changes in air temperature or changes in precipitation were the cause of variations in snowfall trends. It was also inconclusive if the elevation or distance from Lake Ontario resulted in increased snowfall trends. Results from this study will aid in seasonal snowfall forecasts in CNY, which can be used to predict future snowfall. Even though the study area is regionally specific, the methods may be applied to other lake effect dominated areas to determine temporal and spatial variations in snowfall. This study will enhance climatologists and operational forecasters' awareness and understanding of snowfall, especially lake effect snowfall in CNY.

This research studies the existing relations of electrical energy consumption among the five geographic regions of Brazil. The period analysed comprehends monthly aggregated data from January, 1979 to March, 2014, with a total number of 423 observations for each one of the five regions of Brazil. By means of SIN (Nationa Interconnected System) the transmissions among subsystems from almost the whole country are possible. Brazil is among the ten most electrical energy consuming countries of the world. The series presented an integration order equal too ne with cointegration, so, to measure these influences a VEC (Vector Error Correction) model was used. Throughout the Impulse Response Function (FIR) and Variancy Decomposition Analysis (ADV) it was possible to verify how each region behaves to an abrupt change in the consumption of the other regions, as well as what is the participation of each region in the variance explanation of each series, the regions with minor consumption showed more vulnerable than the others. The conclusions were that there are significative relationships between the demands of electricity in the regions surveyed, their behavior depends basically on the geographic proximity between them and its participation on the national electrical energy consumption.
Esta pesquisa estuda as relações existentes no consumo de energia elétrica entre as cinco regiões geográficas do Brasil. O período de análise compreende dados agregados mensais de janeiro de 1979 até março de 2014 perfazendo um total de 423 observações para cada uma das cinco regiões do Brasil. Por meio do Sistema Interligado Nacional (SIN) são possíveis as transmissões entre subsistemas de praticamente todo o país. O Brasil está entre os dez maiores consumidores de energia elétrica do mundo. As séries apresentaram ordem de integração igual a um com a presença de cointegração, assim, para mensurar essas influências foi utilizado um modelo de Vetor de Correção de Erros (VEC). Por meio da Função Impulso Resposta (FIR) e Análise de Decomposição da Variância (ADV) foi possível verificar como cada região se comporta a uma mudança abrupta no consumo das demais regiões, bem como qual a participação de cada região na explicação da variância de cada série, as regiões de menor consumo se mostraram mais vulneráveis às demais regiões. As conclusões foram de que há relações significativas entre as demandas de energia elétrica nas regiões pesquisadas, o comportamento delas depende basicamente da proximidade geográfica entre as mesmas e da sua participação no consumo nacional de energia elétrica.

Entre le bassin d'alboran et le detroit de sicile, l'eau atlantique modifiee (maw) est conduite vers l'est le long de la cote nord africaine par le courant algerien. Les echelles de variabilite spatiale et temporelle du courant algerien sont etudiees a l'aide de cartes altimetriques (sla) et infrarouges (sst). Quelques tourbillons anticycloniques sont observes avec une claire signature en anomalie du niveau de la mer et en temperature de surface. Les zones de faible variabilite a mesoechelle presente un haute correlation entre sla et sst, avec un decalage de 20-30 jours du a l'effet sterique du cycle saisonnier. Une analyse en fonctions orthogonales empiriques complexes (ceof) est effectuee sur les cartes sla qui combinent les donnees des altimetres de ers-1 et topex/poseidon tous les dix jours entre novembre 1992 et decembre 1993 avec une resolution spatiale de 0. 2 degre. Les deux premiers modes expliquent presque 85% de la variabilite, dont 80% de la variance totale pour le premier mode et 5% pour le second mode. L'importance du second mode est verifiee au moyen de plusieurs simulations d'analyse ceof. La phase temporelle du premier mode indique une frequence constante de un cycle par an correspondant au signal saisonnier tres dominant. Une forte amplitude de ce mode est observee dans la partie sud du canal de sardaigne et pourrait etre liee a la variabilite saisonniere du flot de maw dans le detroit de sicile. La phase et l'amplitude temporelles du second mode revelent une periode de six mois qui semble associee a la variabilite du courant algerien. L'amplitude spatiale montre deux points cotiers de grande variabilite avec une propagation vers le nord qui pourraient correspondre au detachement de tourbillons du courant principal, comme cela est observe a partir des donnees courantometriques de l'experience primo-1 pres du canal de sardaigne. Plusieurs parcours de propagation des tourbillons anticycloniques sont proposes dans le bassin algerien avec quelques zones d'interaction entre tourbillons. Dans la region tunisie-sardaigne-sicile, l'activite de mesoechelle n'est pas aussi bien detectee que dans le bassin algerien au moyen de cartes sla, probablement a cause des plus petites echelles spatiales et temporelles de la variabilite dans cette zone. Cependant, quelques caracteristiques saisonnieres du flot de maw sont soulignees.

Ecological communities are most commonly structured by a mixture of bottom-up processes such as habitat or prey, competition within the same trophic level, and top-down forces from higher trophic levels. Carnivore guilds play a vital role in the broader ecological community by stabilizing or destabilizing food webs. Consequently, factors influencing the structure of carnivore guilds can be critical to patterns in ecosystems. Coyotes (Canis latrans), bobcats (Lynx rufus), gray foxes (Urocyon cinereoargenteus), raccoons (Procyon lotor), red foxes (Vulpes vulpes), and striped skunks (Mephitis mephitis) occur sympatrically throughout much of their geographic ranges in North America and overlap in resource use, indicating potential for interspecific interactions. Although much is known about space use, habitat relationships, and activity patterns of the individual species separately, little is known about factors that facilitate coexistence and how interactions within this guild influence distribution, activity, and survival of the smaller carnivores. For example, gray fox populations appear to have declined in Illinois since the early 1990s and it is unknown if the increase in bobcat and coyote populations during the same time period is the cause. I conducted a large-scale non-invasive carnivore survey using an occupancy modeling framework to quantify factors affecting the structure of this widely-occurring carnivore guild. I used baited remote cameras during 3-week surveys to detect carnivores at 1,118 camera-points in 357 2.6-km2 sections (clusters of 3-4 cameras/section) in the 16 southernmost counties of Illinois (16,058 km2) during January-April, 2008-2010. I collected microhabitat data at each camera-point and landscape-level habitat data for each camera-cluster. In a multi-stage approach, I used information-theoretic methods to develop and evaluate models for detection, species-specific habitat occupancy, multi-species co-occupancy, and multi-season (colonization and extinction) occupancy dynamics. I developed hypotheses for each species regarding the occupancy of areas based on anthropogenic features, prey availability, landscape complexity, and vegetative landcover. I used photographic data, Poisson regression, and mixed-model logistic regression to quantify temporal activity of carnivores in the study area and how interspecific factors influence temporal patterns of activity. Of the 102,711 photographs of endothermic animals I recorded photographs of bobcats (n = 412 photographs), coyotes (n = 1,397), gray foxes (n = 546), raccoons (n = 40,029), red foxes (n = 149) and striped skunks (n = 2,467). Bobcats were active primarily during crepuscular periods, and their activity was reduced with precipitation and higher temperatures. The probability of detecting bobcats at a camera point decreased after a bobcat photograph was recorded, suggesting avoidance of remote cameras. Across southern Illinois, bobcat occupancy at the camera-point and camera-cluster scale (point = 0.24 ± 0.04, cluster = 0.75 ± 0.06) was negatively influenced by anthropogenic features and infrastructure. Bobcats had high rates of colonization (0.86) and low rates of extinction (0.07) during the study, suggesting an expanding population, but agricultural land was less likely to be colonized. The number of coyote photographs decreased with increased temperature, but increased with previous coyote photographs, suggesting an attraction to bait in cold weather. Nearly all camera clusters were occupied by coyotes (cluster = 0.95 ± 0.03) during the entire study. At the camera-point scale, coyote occupancy (overall point = 0.58 ± 0.03) was higher in hardwood forest stands with open understories than in other habitats. Similar to coyotes, gray foxes were more likely to be photographed in cold weather and after a previous detection had occurred. However, gray fox occupancy was much lower (point = 0.13 ± 0.01, cluster = 0.29 ± 0.03) at all scales. At the camera-cluster scale, with a buffer-area size that represented 20% of the estimated home-range size of gray foxes, the species selected spatially-complex areas with high proportions of forest, and low proportions of grassland and agriculture land cover. Gray fox occupancy of camera clusters was positively related to anthropogenic features within 100% estimated home-range buffers. Collectively, the results suggest gray fox occupancy was greatest near, but not in, anthropogenic developments. Red foxes occupied a similar proportion of the study area as gray foxes (point = 0.12 ± 0.02, cluster = 0.26 ± 0.04), but were more closely associated with anthropogenic features. Indeed, at all three scales of red fox occupancy analysis, anthropogenic feature models received more support than other hypotheses. Camera-cluster extinction probabilities were higher for both gray foxes (0.57) and red foxes (0.35) than their colonization rates (gray fox = 0.16, red fox = 0.06), suggesting both species may be declining in southern Illinois. I recorded more striped skunk photographs in January and February (i.e., during the breeding period) than in March and April. Striped skunks occupied a large portion of the study area (point = 0.47 ± 0.01, cluster = 0.79 ± 0.03) and were associated primarily with anthropogenic features, especially if the features were surrounded by agricultural land and not forest. Raccoons were essentially ubiquitous within the study area, being photographed in 99% of camera clusters. In some instances, the presence of other carnivores appeared to be an important factor in the occupancy of the 4 smaller species, but in general, habitat models were more supported than co-occurrence models. Habitat had a stronger influence on the occupancy of gray foxes and red foxes than did the presence of bobcats. However, the level of red fox activity, represented by the number of photographs recorded in a camera cluster, was negatively correlated with bobcat activity. Gray fox occupancy and level of activity were reduced in camera-clusters occupied by coyotes, but were not related to bobcat occupancy. When not considering the presence of coyotes, gray foxes appeared to use camera points with fewer hardwood and more conifer trees, which was counter to previous findings. However, when adding the effect of coyote presence, gray fox point models indicated a positive relationship with hardwood stands. Therefore, gray foxes were more likely to occupy camera points in hardwood stands than conifer stands if coyotes were also present; suggesting that hardwood stands may enhance gray fox-coyote coexistence. The 2 fox species appeared to co-occur with each other at the camera-point scale more frequently than expected on the basis of their individual selection of habitat. Similarly, camera-point occupancy of red foxes was higher when coyotes were present. These apparent canid associations may be a response to locally-high prey abundance or an unmeasured habitat variable. Activity levels of raccoons, bobcats, and coyotes were all positively correlated. Collectively, my results suggest that although gray foxes and red foxes currently coexist with bobcats and coyotes, the foxes have reduced activity in the areas occupied by larger carnivores, especially when bobcats and coyotes are highly active. Further, hardwood stands may contain trees with structure that enhances tree-climbing by gray foxes, a behavior that probably facilitates coexistence with coyotes. Therefore, efforts to manage gray foxes should focus on maintaining and increasing the amount of mature oak-hickory forest, which presumably provides a suitable prey base and refugia from intraguild predation. Additionally, the varying results from different scales of analyses underscore the importance of considering multiple spatial scales in carnivore community studies.

Bibliography: pages 96-103.
This thesis presents the results of a current meter experiment performed in the St Helena Bay - Cape Columbine region during winter 1982. The work, which forms part of the shelf dynamics programme undertaken by the Sea Fisheries Research Institute, attempts to identify the important time and spatial scales within the coastal currents and to investigate the relationship between the sub-inertial flow and low frequency variations in the coastal winds.

Une perte auditive neurosensorielle est généralement associée à uneréduction de l’intelligibilité de la parole, et ce tout particulièrement dans le bruit.Les contributions respectives d’une réduction de l'audibilité et de déficitssupraliminaires sont encore débattues.L'objectif principal de cette thèse était d'évaluer l'effet spécifique desdéficits supraliminaires sur l’intelligibilité de la parole. L'effet de l'audibilité étaitcontrôlé en mesurant l’intelligibilité de signaux de parole sans signification filtrésdans les régions basses et moyennes fréquences au sein desquelles la détection desons purs était normale chez des auditeurs malentendants présentant par ailleursune perte auditive en hautes fréquences. Dans ces régions fréquentielles oùl’audibilité est supposée normale, des déficits d'intelligibilité de la parole légers àsévères ont été observés dans le silence comme dans le bruit chez les auditeursmalentendants. Les déficits étaient similaires dans les bruits masquantstationnaires et fluctuants. Ces résultats démontrent l’influence des déficitsauditifs supraliminaires sur l’intelligibilité de la parole.Le second objectif de cette thèse était d'étudier l'origine de ces déficitssupraliminaires. Les résultats indiquent qu’une réduction de la sélectivitéfréquentielle cochléaire ne peut pas expliquer entièrement les déficitsd’intelligibilité de la parole des auditeurs malentendants. L'influence de lasensibilité à la structure temporelle fine reste incertaine
Speech intelligibility is reduced for listeners with sensorineural hearingloss, especially for speech in noise. The extent to which this reduction is due toreduced audibility or to supra-threshold deficits is still debated.The main goal of this PhD work was to investigate the specific influenceof supra-threshold deficits on speech intelligibility. The effect of audibility wascontrolled for by measuring speech intelligibility for hearing-impaired listenersusing nonsense speech signals filtered in low- and mid-frequency regions wherepure-tone sensitivity was normal. Hearing-impaired listeners with hearing loss inhigh-frequency regions showed mild to severe intelligibility deficits for speechboth in quiet and in noise in these frequency regions of normal audibility. Similardeficits were obtained for speech in steady and fluctuating masking noises. Thisprovides additional evidence that speech intelligibility may be strongly influencedby supra-threshold auditory deficits.The second aim of this PhD work was to investigate the origin of thesesupra-threshold deficits. Results showed that reduced frequency selectivity cannotentirely explain the speech intelligibility deficits of the hearing-impaired listeners.The influence of temporal fine structure sensitivity remained unclear

As video capturing devices become more ubiquitous from surveillance cameras to smart phones, the demand of automated video analysis is increasing as never before. One obstacle in this process is to efficiently locate where a human operator’s attention should be, and another is to determine the specific types of activities or actions without ambiguity. It is the special interest of this dissertation to locate spatial and temporal regions of interest in videos and to develop a better action representation for video-based activity analysis. This dissertation follows the scheme of “locating then recognizing” activities of interest in videos, i.e., locations of potentially interesting activities are estimated before performing in-depth analysis. Theoretical properties of regions of interest in videos are first exploited, based on which a unifying framework is proposed to locate both spatial and temporal regions of interest with the same settings of parameters. The approach estimates the distribution of motion based on 3D structure tensors, and locates regions of interest according to persistent occurrences of low probability. Two contributions are further made to better represent the actions. The first is to construct a unifying model of spatio-temporal relationships between reusable mid-level actions which bridge low-level pixels and high-level activities. Dense trajectories are clustered to construct mid-level actionlets, and the temporal relationships between actionlets are modeled as Action Graphs based on Allen interval predicates. The second is an effort for a novel and efficient representation of action graphs based on a sparse coding framework. Action graphs are first represented using Laplacian matrices and then decomposed as a linear combination of primitive dictionary items following sparse coding scheme. The optimization is eventually formulated and solved as a determinant maximization problem, and 1-nearest neighbor is used for action classification. The experiments have shown better results than existing approaches for regions-of-interest detection and action recognition.

Avec les lancements réussis des missions ESA Soil Moisture and Ocean Salinity (SMOS) et NASA Aquarius/SAC-D, la salinité de surface des océans peut maintenant être déduite. De plus, les produits de couleur de l'eau, tels que les mesures d'absorption et d'atténuation de la lumière et de concentration en chlorophylle, peuvent être utilisés comme traceurs de la salinité. Les signatures des panaches des grands fleuves tropicaux tels que l'Amazone et l'Orénoque peuvent être étudiées en détail grâce à ces nouvelles méthodes. En particulier, les relations de corrélations entre SSS et propriétés optiques également déduites de mesures satellites peuvent maintenant être établies et analysées sur des échelles spatiales beaucoup plus grandes. Différents efforts de recherche sont envisagés dans le cadre de ce travail de thèse. Tout d'abord, nous étudions les corrélations entre salinité de surface et propriétés optiques dans le panache de l'Amazone durant la période 2010-2013. Ensuite, la relation de mélange est établie de façon robuste selon tout d'abord une approche régionale, puis selon une approche locale. Ensuite, une fois cette loi de dilution établie de façon robuste, nous l'utilisons pour estimer un produit de salinité de surface à partir des produits couleur de l'eau sur la période 1998-2013. Enfin, nous tentons d'envisager la relation de dilution suivant une approche lagrangienne
We enter now in a new era of global Sea Surface Salinity (SSS) observing systems from Space with therecent successful launches of the ESA Soil Moisture and Ocean Salinity (SMOS) mission and the NASA Aquarius/SAC-D mission. These new satellite SSS observing systems are as well complemented by an increased number of devices deployed in situ. Finally, ocean color products can be used as well for tracking salinity via semi-conservative tracers such as dissolved organic matter absorption coefficient at 443 nm(acdm), light attenuation at 490 nm and chlorophyll concentration. With these new methods, we are now in an excellent position to revisit the SSS observed in the warm seas of the tropical Atlantic with multi-yeartime series of excellent remote sensing and concurrent in situ observations. The seasonal cycles in the spatial extent of low surface salinity waters of the major river plumes and freshwater pools of the tropical Atlantic oceans as the Amazon and Orinoco rivers can thus be analyzed in a new and original manner. In particular, the correlation between SSS and bio-optical properties measured from Space in the plume waters can now beestablished and analyzed over large spatial scales. In the frame of this PhD work, different major research topics were studied. First the correlations between sea surface salinity and absorption coefficient of colored detrital matter at 443 nm in the Amazon-Orinoco plume over 2010-2013 are studied. Then the conservative mixing relationship is robustely established based on two different approaches, a regional one over the whole Amazon plume and a local one. Once the SSS/acdm relationship established, it is used to retrieve a SSSproduct from 1998 to 2013 based on Ocean Color data. Finally, we attempt to explore the conservative mixing using a lagrangian approach

The variability of water-column absorption due to colored dissolved organic matter (CDOM) and phytoplankton in coral reef regions is the focus of this study. Hydrographic and CDOM absorption measurements made on the Bahamas Banks and in Exuma Sound during the spring of 1999 and 2000 showed that values of salinity and CDOM absorption at 440nm were higher on the banks (37.18 psu, 0.06 m^-1), compared to Exuma Sound (37.04 psu, 0.03 m^-1). Spatial patterns of CDOM absorption in Exuma Sound revealed that plumes of CDOM-rich water flow into Exuma Sound from the surrounding banks. To examine absorption variability in reef regions throughout the world, a thirteen-year time series of satellite-derived estimates of water-column absorption due to CDOM and phytoplankton were created from Sea-viewing Wide Field-of-view Sensor (SeaWiFS) and Moderate Resolution Imaging Spectroradiometer (MODIS) data. Time series data extracted adjacent to coral reef regions showed that variability in absorption depends on oceanographic conditions such as circulation patterns and winds as well as proximity to sources of light-absorbing materials that enter the water column, such as from terrestrial runoff. Waters near reef regions are generally clear, exhibiting a lower "baseline" level of CDOM absorption of approximately 0.01 m^-1 at 443nm. The main differences between regions lie in the periods during the year when increased levels of absorption are observed, which can be triggered by inputs of terrestrially-derived material, as in the Great Barrier Reef lagoon, or wind-driven upwelling as in the Andaman Sea and eastern Pacific Ocean near Panama. The lowest CDOM absorption levels found were approximately 0.003 m^-1 at 443nm near the islands of Palau and Yap, which are removed from sources of colored materials. The highest absorption levels near reefs were associated with wind-driven upwelling during the northeast monsoon on the Andaman coast of Thailand where values of CDOM absorption at 443nm reached 0.7 m^-1. Simulations of the underwater light field based on satellite-derived absorption values revealed that changes in absorption have a strong influence on light levels to which corals are exposed, particularly in the ultraviolet region of the spectrum, where CDOM is the primary absorber of light. Episodes of coral bleaching during 1998 and 2002 were found to be associated with elevated seawater temperatures as well as decreased levels of CDOM absorption, indicating that corals were exposed to light stress along with thermal stress during periods of bleaching.

Moment-radius-stress drop relations and composite focal mechanisms were determined for 33 small, shallow, strike slip earthquakes (1.7$MLS4.3) in the Matsushiro region of southwest Honshu, Japan during the period August 1971 through September 1974. Estimates of the scalar moment derived from deconvolved SH displacement amplitude spectra range from 1018 to 1022 dyne-cm. The apparent stress ranges from 0.001 to 3.00 bars and the relationship between apparent stress and moment is approximately linear with a slope of 1.
Ph. D.

The objective of this research is to evaluate temporal adjustments of a streambed surface due to changes in the sediment supply regime. To achieve the goals, laboratory experiments were conducted in an 18 m long, 1 m wide flume with a gradient of 0.0218. The bed was brought to an armored state by running water with no sediment feed before releasing a sequence of sediment pulses. Water discharge and grain size distribution of the sediment feed were held constant over the set of experimental runs, while supply input rates and magnitudes varied. Sediment flux at the outlet of the flume was continuously measured. At frequent time intervals, bed surface texture, 1 mm vertical resolution bed elevation, and microtopographical cluster features were measured over a two meter section of the flume bed. Instantaneous three-dimensional observations of flow velocities were made using an Acoustic Doppler Velocimeter. Surface texture adjustments in response to the sediment supply regime followed similar patterns between all runs involving pulses of sediment in that (1) the D₁₆ – the diameter at which 16% of the particles are smaller than – was the most variable characteristic grain size value and (2) medium-gravel patch areas were least variable, likely due to higher relative mobility of fine material. Fine-gravel patch areas developed following sediment pulses and persisted over time even once the overall characterization of the bed had returned to an armored state. Increases in bed roughness, quantified by the standard deviation of bed elevations (σz), were consistently paralleled with increases in the number of identified clusters and their combined surface area. Cluster formation was seemingly random, but expansion occured only once surface texture became relatively coarse and bed roughness increased. These results inform about the degree of bed surface evolution complexity under conditions of variable sediment supply and can be linked to observations and predictions of sediment transport in field settings.

Memoria para optar al título profesional de Ingeniero Agrónomo. Mención Enología y Vitivinicultura
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La escasez de mano de obra temporal agrícola, constituye una problemática a nivel país y puede ser abordada mediante el estudio del compromiso que establecen los trabajadores con sus organizaciones. Desde este punto de vista, existen diversos estudios que tratan el Compromiso Organizacional; pero no específicamente en trabajadores agrícolas temporales, surgiendo así la necesidad de explorar éste tema, por lo anterior el propósito de ésta investigación fue conocer el Compromiso Organizacional de trabajadores agrícolas temporales en arándanos en la comuna de Gorbea, IX Región de Chile y su relación con variables demográficas (género, edad, estado civil, nivel educacional, lugar de residencia, lugar de origen) y del trabajo (cargo en la empresa, antigüedad en el cargo y en la empresa, entre otros). Para ésto se identificó la composición de la mano de obra agrícola temporal, identificó los tipos de Compromiso Organizacional que poseen y analizó si el Compromiso Organizacional está relacionado con variables sociodemográficas (demográficas y del trabajo). Para el logro de éstos objetivos, se aplicó una encuesta de Compromiso Organizacional a 113 trabajadores agrícolas temporales. El análisis de la información se llevó a cabo mediante análisis descriptivo univariante, de componentes principales, prueba t de Student y ANOVA. Como resultado se obtuvo que los trabajadores, en su mayoría son hombres, entre 30 y 39 años, con residencia cercana al trabajo, casados, enseñanza media completa, cuyo cargo principal es de podador y planean volver a trabajar en la empresa. Presentan seis tipos de compromiso: Satisfacción general con el trabajo, Compromiso con el trabajo, Compromiso de conveniencia, Compromiso afectivo, Sentimiento de permanencia y Jerarquía del puesto y finalmente, no existe relación directa entre el Compromiso Organizacional y variables sociodemográficas. Se concluye que la muestra está condicionada por la época del año y actividades que se realizan en dicho período. Las seis dimensiones encontradas son consistentes con otros estudios que utilizaron el mismo instrumento de medición y se logró determinar algunas asociaciones entre dimensiones del compromiso y variables sociodemográficas. Esta primera exploración pretende aportar a futuros estudios que otorguen información valiosa a las organizaciones sobre el Compromiso Organizacional en los trabajadores agrícolas de temporada.
The growing shortage of agricultural temporary labor, is a country-level issues can be addressed by studying the commitment to provide employees with their organizations. From this point of view, several studies dealing with Organizational Commitment, but not specifically in seasonal agricultural workers, arises the need to explore this subject, above the purpose of this research was to determine the organizational commitment of temporary agricultural workers blueberries at Gorbea area, Chile and its relationship with demographic variables (gender, age, marital status, educational level, residence, place of origin) and work (position in the company, seniority and in the company, among others). To this was identified the composition of the temporary agricultural labor, identified the types of organizational commitment and have examined whether organizational commitment is related to sociodemographic variables (demographic and labor). To achieve these objectives, a survey of Organizational Commitment to 113 seasonal farm workers. The data analysis was performed using descriptive univariate analysis, principal components, Student's t test and ANOVA. The result was that workers are mostly men between 30 and 39 years, residing close to work, married, complete high school, whose main office is trimmer and plan to return to work in the company. They have six types of Commitment: Overall satisfaction with work, work commitment, commitment of convenience, affective commitment, Feeling of permanence and hierarchy of the post and finally, there is no direct relationship between organizational commitment and demographic variables. We conclude that the sample is conditioned by the season and activities performed during that period. The six dimensions found are consistent with other studies using the same measuring instrument and managed to identify some associations between dimensions of commitment and sociodemographic variables. This first exploration seeks to contribute to future studies give valuable information to organizations on the Organizational Commitment in seasonal agricultural workers.

O objetivo do presente trabalho consiste no estudo das características dos sedimentos de superfície de fundo da Baía da Ilha Grande, estado do Rio de Janeiro, e sua correlação com os processos hidrodinâmicos atuais,bem como com a evolução sedimentar do litoral paulista e sul-fluminense a partir do máximo regressivo do Pleistoceno Superior. A baía da Ilha Grande consiste num corpo de água definido pela presença da Ilha Grande. Pode ser dividida em três unidades fisiográficas distintas, a saber: Porção Oeste, Porção Leste e Canal Central. Para o presente estudo, foi coletado um total de 153 amostras de superfície de fundo e realizado um conjunto de análises sedimentológicas constituído por: análise granulométrica, análise morfométrica e de textura superficial, análise de conteúdo em carbonato biodetrítico, analise de conteúdo em matéria orgânica, análise dos constituintes na fração grosseira e analise de assembléias de minerais pesados. Os estudos realizados permitiram identificar quatro fácies sedimentares distintas, caracterizadas como: sedimentos relíquias da Porção Leste, sedimentos atuais do Canal Central e das áreas abrigadas, sedimentos transgressivos da Porção Oeste e sedimentos mistos resultantes da mistura de termos das fácies anteriores.Finalmente, é feita uma proposta de evolução sedimentar da área a partir do máximo regressivo de 18.000 anos A.P. estabelecidas considerações sobre a dinâmica de fundo da baía.
The objective of the present work is to study the characteristics of the surface bottom sediments of Ilha Grande Bay, Rio de Janeiro state, and their correlation with the modern hydrodynamic processes, as well as with the sedimentary evolution of the southeastern brazilian coastal region, since the maximum regression of the Upper Pleistocene. Ilha Grande Bay consista a water body defined by the presence of Ilha Grande island. It can be divided into three distinct fisiographic units: the Western Portion, the Eastern Portion, and the Central Channel. In this work, a total of 153 surface bottom samples were collected, and the sediments were anal zed for: grain size, morphometry and surface texture, carbonate content, organic matter content, coarse fraction constituents, and heavy mineral assemblages. The studies allowed to identify four distinct sedimentary facies, characterized as: relict sediments of the Eastern Portion, modern sediments of the Central Channel and the confined areas, transgressive sediments of the Western Portion, and mixed sediments, resulting from the mixture of the previous facles. Finally, we propose amodel for the sedimentary evolution of the area since the maximum regressive of 18,000 years B.P. and considerate on the bottom dynamic of the bay.

La dificultad de disponer de series de referencia largas fiables para Cantabria nos llevó a plantearnos el problema de su reconstrucción estadística a través de un proceso de homogeneización. Tras dicha elaboración presentamos una cartografía que expresa la variabilidad de la Precipitación y la Temperatura a lo largo del siglo XX. Partimos de la existencia de contrastes regionales entre los cuales, los más significados, identifican dos comarcas de Cantabria con características bioclimáticas bien diferenciadas: el sector central de la Marina en la vertiente cantábrica y el valle de Campoo en la vertiente mediterránea. Los datos de partida, tomando como base las estaciones de Santander y Reinosa, constituyen una serie fragmentada en el tiempo que se ha completado interpolando los valores conocidos de un elevado número de estaciones en función de la distancia, en cada uno de los sectores previamente establecidos. A su vez, la irregular distribución espacial de las observaciones se ha resuelto estableciendo la correlación de las series climáticas con las variables espaciales altitud, latitud, longitud y orientación, entre otras, lo que nos ha permitido completar un conjunto de registros con elevada coherencia temporal y espacial. La inclusión de las series más largas y representativas de cada una de las comarcas, ha estado precedida de la búsqueda e incorporación de algunos periodos de observación inéditos y de un análisis crítico de los datos más antiguos. En esta etapa, no hemos servido de los métodos que la Climatología Histórica aplica al analizar los registros que proceden de fuentes documentales.
We have developed maps of the variability of precipitation and temperature in two different bioclimatic areas in the central sector of the north coast of Spain: one coastal in the Biscay basin, and one inland in the Mediterranean basin, throughout the twentieth century. Data gaps have been filled with the distance weighted interpolation (IDW), while the spatial distribution of observations is resolved by the correlation with the spatial variables calculated with a digital elevation model. Thus we have completed a data set with high temporal and spatial coherence. The inclusion of the longest and most representative series of the areas was preceded by the incorporation of some unpublished records and critical analysis of older data. For this we use Historical Climatology methods to analyse records from documentary sources.

Despite their importance to regional biodiversity, temporary wetlands and their invertebrate communities are generally understudied and under-conserved. Resurrection ecology is used to study the communities present in the dry phase of temporary wetlands to gain a better understanding of the functioning and health of these systems. The hatching success of invertebrate propagules in dried soil sediments, collected from temporary wetlands in Cape Sand Fynbos regions of Cape Town, were investigated in 2016. Soil samples were collected from conserved and urban sites (during May and June 2016) using a standard soil auger method and complemented with monthly aquatic phase sampling using standard sweep net methods (during September and October 2016). The effects of fire were tested, on hatching success by staging vegetation fires over the collected soil samples for five temporary wetland areas in the same region. Mann-Whitney U tests were used to test differences in abundances between treatments, whereas for comparison of taxon richness, Shannon diversity and Pielou's evenness linear mixed effect models (LMER) were used. Non-metric multidimensional scaling (nMDS) plots were used to graphically visualize the community composition between the different treatments, with 'adonis' analysis used to test their statistical significance. Results found a total of 18 invertebrate taxa hatched, while a total of 27 taxa were identified from the wet phase. Results from hatching assays showed no significant differences in diversity patterns of invertebrates between conserved and urban areas in the dry phase. However, wetlands that were in the conserved area supported higher invertebrate diversity during the wet phase, although not significant (lmer, Z = -1.75, p = 0.08). These results suggest that human activity (alien vegetation, littering and polluting) in the area did not impact the ability of invertebrate propagules to emerge, but did slightly affect the natural aquatic phase. Fire had a significantly negative impact on invertebrate diversity measures (lmer, p < 0.001) and community composition (adonis, F = 24.494, p = 0.001) during hatching assays. Management of unpredicted and uncontrolled fire in urban areas is essential to ensure future protection of critical biodiversity areas created by these temporary wetlands. More research should focus on the impact of increasing fire frequency and intensity on these systems to understand the management challenges in a changing climate.

Objective: Deficits in temporal resolution may be one element underlying the speech understanding difficulties experienced by older listeners in degraded acoustic environments. In real listening environments, important temporal cues are surrounded by stimuli of varying frequencies. This study was designed to assess temporal resolution as a function of frequency region, frequency-disparity, and age in listeners with normal hearing. Design: Gap duration difference limens (GDDLs) were measured using leading and trailing markers that were fixed at the same frequency (fixed-frequency) or at frequencies one-half octave apart (frequency-disparate) for two groups of listeners with normal hearing: (1) 18-22 years and (2) 55-66 years. Two distinct frequency regions were represented, 500 Hz and 4000 Hz. Results: The results indicated significant effects of age, frequency region, and frequency disparity on GDDLs. Poorer overall performance was observed for the older listeners, the lower frequency region, and the frequency-disparate condition. Conclusions: Gap discrimination is negatively affected by advanced age, lower marker frequencies, and larger marker frequency disparities.

It is estimated that free-roaming dogs comprise on average 75% of dog populations. Interactions between free-roaming dogs and wildlife occur across the globe but little is known about these interactions in the Lowveld region of South Africa, where wildlife areas are fenced off from surrounding communities. Even with extensive fences dogs are still entering the reserves. The study site, a private reserve in eastern Mpumalanga Province on the western boundary of the Greater Limpopo Transfrontier Park, has a high density of human settlements on its boundary. These communities own dogs, many of which are free-roaming. Between January 2009 and March 2014, 170 stray dogs were destroyed inside the reserve and 65.3% of the samples returned a positive result for rabies. Dogs are not limited to the reserve edges and have been documented several kilometres into the reserve. Eleven geographical factors were used in the spatial analysis: (i) camps or lodges in the reserve, (ii) fence line of the reserve, (iii) water points within the reserve, both natural and man-made (excluding rivers but including pans, dams and waterholes which hold water for most of the year), (iv) access roads from gates to camps and lodges, (v) access gates into the reserve, (vi) pickets (field ranger accommodation) and general staff accommodation, (vii) rivers in stream order from 1 to 6, (viii) vulnerable points for erosion along the fence line, and (ix) villages bordering the reserve. GPS locations of dogs shot were used to obtain nearest distance to each factor. Generalized linear models (GLM) were then used to analyse the spatial data of distance of dogs shot to the nearest factor. Dogs were significantly more likely to be shot further away from pickets and closer to minor rivers. There was a significant interaction between these two factors (p < 0.0001). Dogs that were shot further from villages (odds ratio 1.42, 95% confidence intervals 1.18 1.71, p = 0.0002) and closer to water (odds ratio 0.41, 95% confidence intervals 0.21 0.81, p = 0.009) were more likely to test positive for rabies. A univariate GLM, with distance to fence as the only explanatory variable, showed a significant association between this and rabies test result: for every 1 km further away from the fence the odds of a dog testing rabies positive increases by 1.68 (95% confidence intervals 1.20 2.36, p = 0.002). However the fence is likely not to be the influencing factor but rather other factors close to the fence. To remove the effect of the fence an analysis of the subset of dogs found further than 200m into the reserve found a positive association between distance from a village and a positive rabies test result (odds ratio 1.58, 95% confidence intervals 1.18-2.32, p = 0.007). Temporal analysis of the data shows a higher average monthly number of dogs shot during the wet season (Oct-Mar) as well as a higher variance although the cycle is not strictly seasonal. An upgrade of the reserve fence for security reasons coincided with a decrease in number of dogs destroyed in the reserve in 2012-1014. Home range analysis of most susceptible predators was collected from daily sightings data and overlaid with rabies hotspots, which gives management an indication of the need to vaccinate predators with home ranges in close proximity to the fence. The spatial results gives management an indication to increase efforts to destroy free-roaming domestic dogs further into the reserve as the likelihood of a positive rabies result is greater. Ultimately efforts should be focused outside the reserve in the communities to eradicate rabies from the host (domestic dogs) before there is a significant transfer of rabies to wildlife.
Dissertation (MSc)--University of Pretoria, 2015.
tm2016
Veterinary Tropical Diseases
MSc

The use of Normalized Difference Vegetation Index (NDVI) time series over the last decades has increased our understanding of vegetation change dynamics from global to regional scale through quantitative analysis of inter-annual trends in NDVI and climatological parameters (rainfall and temperature). Change in land cover induced by human activities such as livestock grazing and deforestation for large-scale farming (subsistence and mechanized) has influenced the ecological pattern of the Guinea savannah region (GSR) of Nigeria, thereby resulting in loss of biodiversity and changes in vegetation cover. In the context of the GSR of Nigeria where agriculture still plays a major role in people’s economy, it is important to identify the relationship between climatic variables, vegetation productivity and human activities which can be used to understand the on-going transition processes. This study, therefore, examines the spatial and temporal relationship between NDVI and climate parameters, land use land cover change (LULCC) and the perspective of local people on vegetation change dynamics in the study region. In order to do this, bi-monthly NDVI3g time series datasets from Global Inventory Modeling and Mapping Studies (GIMMS), monthly rainfall datasets from Tropical Applications of Meteorology Satellite (TAMSAT), monthly temperature datasets from Climate Research Unit (CRU), national land use land cover (LULC) data of Nigeria from Forestry Management Evaluation & Coordination Unit (FORMECU), global land cover datasets from European Space Agency, Landsat imagery and socio-economic field data collection were used in order to understand vegetation change dynamics across the Guinea savannah regions of Nigeria. Time series analysis (TSA) was applied to both NDVI and climate data used in order to examine the temporal dynamics of vegetation cover change and to detect NDVI-climate relationship during the period from 1983 through 2011. Both parametric and non-parametric statistical models were employed for the assessment of long-term inter-annual trend on the decomposed time series datasets for the whole region (Guinea savannah region) and selected locations. In addition to the TSA, harmonic regression analysis was performed on NDVI and rainfall datasets in order to examine change in seasonality and phyto-phenological characteristics of vegetation. Detection of change in land use and land cover was done by extracting information from existing land cover datasets (ancillary datasets). CLASlite was used for the assessment of the extent of deforestation, while linkage between remotely sensed data and social science was carried out via field surveys based on questionnaires in order to understand the drivers of vegetation change. The study reveals that about 90 % of the Guinea savannah region show positive NDVI trends which indicate greening over time, while about 10 % of the region shows negative trends. This greening trends are closely related to regions where intensive agriculture is being practiced (also along inland valleys) while regions with negative trends show significant loss in woodlands (forest and shrublands) as well as herbaceous vegetation cover due to over-grazing by agro-pastoralism. The result confirms that there is a good relationship (statistically significant positive correlation) between rainfall and NDVI both on intra-annual and inter annual time scale for some selected locations in the study region (> 65 %), while negative statistical correlation exists between NDVI and temperature in the selected locations. This implies that vegetation growth (productivity) in the region is highly dependent on rainfall. The result of the harmonic regression analysis reveals a shift in the seasonal NDVI pattern, indicating an earlier start and a more prolonged growing season in 2011 than in 1983. This study proves significant change in LULC with evidence of an increase in the spatial extent of agricultural land (+ 30 %) and loss of woodlands (- 55 %) between 2000 and 2009 for Kogi State. The results of the socio-economic analysis (people’s perception) highlight that vegetation change dynamics in the study region are the resultant effects of increased anthropogenic activities rather than climatic variability. This study couples data from remote sensing and ground survey (socio-economics) for a better understanding of greening trend phenomena across the Guinea savannah region of Nigeria, thus filling the gap of inadequate information on environmental condition and human perturbation which is essential for proper land use management and vegetation monitoring.

Thesis (PhD)--Stellenbosch University, 2015.
ENGLISH ABSTRACT: Understanding how divergent selection results in the evolution of reproductive isolation (i.e. speciation) is an important goal in evolutionary biology. Populations of herbivorous insects using different host plant species can experience divergent selection from multiple selective pressures which can rapidly lead to speciation. Restio leafhoppers are a group of herbivorous insect species occurring within the Cape Floristic Region (CFR) of South Africa. They are specialised on different plant species in the Restionaceae family. Throughout my thesis I investigated how bottom-up (i.e. plant chemistry/morphology of host plant species) and top-down (i.e. predation and competition) factors drive specialisation and divergence in restio leafhoppers. I also investigated interspecific competition as an important determinant of restio leafhopper community structure. In chapter 2 I quantified host specificity of restio leafhopper species within a local community for 24 months. I found that restio leafhopper species are highly host specific and potentially synchronised with the growth phases of their host plants. In chapter 3 I used a network metric, modularity, to determine whether host plant partitioning in a restio leafhopper community is non-random (i.e. driven by a deterministic process). This metric allows the identification of the components underlying host plant partitioning (modules). I then performed experiments to show that modules, and therefore host plant partitioning, can mostly be explained by preference and performance relationships (i.e. bottom-up factors). In chapter 4 I used null models to test whether niche partitioning in restio leafhopper communities is a general pattern across the landscape. I found non-random niche partitioning, which results from strong host specificity, in all investigated restio leafhopper communities. In addition, I performed binary host choice experiments in the presence and absence of interspecific competition, but found no evidence that interspecific competition narrows host preferences. These findings suggest that host specificity, the cause of niche partitioning, is likely shaped over evolutionary time. Sampling multiple interaction networks across the CFR, in chapter 5, I tested whether restio leafhopper populations are more host specific in species rich communities and regions in the CFR than in species poor communities and regions. I found no positive relationship between restio leafhopper species richness and host specificity at any scale. These findings suggest that specialisation is not driven by interspecific competition. In chapter 6 I investigated host shifts in Cephalelus uncinatus. C. uncinatus has a broader distribution than any single restio species that it can use; suggesting that host plant related divergence may result from geographic range expansion. I found that allopatric and parapatric populations, but not sympatric individuals, using different host plants have divergent host preferences. I also found evidence for morphological divergence in traits related to predator avoidance in population pairs that exhibit divergent host preferences. My findings emphasise the importance of both bottom-up and top-down factors, with the exception of interspecific competition, as determinants of specialisation and divergence in restio leafhoppers. I find no evidence that interspecific competition is an important force structuring restio leafhopper communities. Instead, strongly niche partitioned community structure appears to emerge from the speciation process.
AFRIKAANSE OPSOMMING: Die wyse waarop uiteenlopende seleksie lei tot die evolusie van seksuele isolasie (n.l. spesiasie) is ‘n belangrike vraag in evolutionêre biologie. Plantetende insekpopulasieses wat verskillende gasheerplante gebruik kan onder uinteenlopende veelvoudige seleksie wees en vinnig spesiasie ondergaan. Restio-blaarspringers is ‘n groep plantetende insekspesies wat gespesialiseerd is op verskillende plantspesies in die restio familie. In my tesis ondersoek ek die onder-op (n.l. plantchemie en morfologie) en bo-af seleksiekragte (n.l. predasie en kompetisie) wat lei tot gasheerspesialisasie en -spesiasie in restio-blaarspringers. Ek ondersoek ook die belangrikheid van tussen-spesieskompetisie in gemeenskapsorganisasie. In hoofstuk 2 het ek gasheerspesialisasie gekwantifiseer in ‘n klein restio-blaarspringergemeenskap oor 24 maande. Ek het gevind dat restio-blaarspringers hoogs gasheerspesifiek is en moontlik met die groeifase van hul hoofgasheerplante gesinchroniseerd is. Ek het in hoofstuk 3 ‘n netwerkmetriek, modulariteit, gebruik om te bepaal of restio-blaarspringers se gasheerverdeling nie-stokasties is (n.l. deur deterministiese prosesse veroorsaak is). Hierdie metriek laat ‘n mens toe om die komponente van gasheerverdeling (modules) te identifiseer. Deur middel van eksperimente het ek bepaal dat modules, en dus gasheerverdeling, deur gasheervoorkeur en prestasie (onder-op prossesse) verduidelik kan word. In hoofstuk 4 het ek ondersoek of gasheerverdeling algemeen is. Ek het deur middel van nulmodelle gewys dat gasheerverdeling algemeen is en veroorsaak is deur sterk gasheerspesifiekheid. Ek het ook voorkeureksperimente uitgevoer in die teenwoordigheid en afwesigheid van tussen-spesies kompetisie. Hier het ek geen teken gevind dat huidige tussen-spesies kompetisie gasheervoorkeur beïnvloed nie. My bevindinge in hierdie hoofstuk stel dus voor dat spesialisasie, die oorsaak van gasheerverdeling, oor evolutionêre tyd gevorm word. In hoofstuk 5 het ek ondersoek of populasies van restio-blaarspringers meer gasheerspesifiek is in restio-blaarspringerspesies ryke gemeenskappe en streke as populasies in spesies-arm gemeenskappe en streke. Ek het geen positiewe korrelasie tussen spesiesrykheid en gasheerspesialisasie gevind nie. Dit dui daarop aan dat gasheerspesialisasie, en dus gasheerverdeling, nie deur tussen-spesies kompetisie veroorsaak word nie. In hoofstuk 6 het ek gasheerplantgekoppelde divergensie ondersoek in Cephalelus uncinatus. C. uncinatus se verspreiding is breër as enige restio-spesies wat dit kan gebruik. Dit stel voor dat verspreidingvergroting gasheerverskuiwing mag veroorsaak. Ek het gevind dat populasies wat verskillende plante in allopatrie en parapatrie gebruik uiteenlopende gasheerkeuses maak, maar insekte wat verskillende plante in sympatrie gebruik wys nie ontwrigtende gasheerkeuses nie. Die populasies wat uiteenlopende gasheerkeuses getoon het, het ook verskillende morfologiese teen-predasie eienskappe getoon. Dit dui daarop aan dat predasie belangrik mag wees vir spesiasie in restio-blaarspringers. Die bevindinge van my tesis dui daarop aan dat beide onder-op en bo-af seleksie belangrik is vir gasheer-spesialisasie in divergensie. Nietemin, tussen-spesies kompetisie is nie ‘n belangrike bron vir spesialisasie, divergensie of gemeenskapsorganisasie nie. Gemeenskapsorganisasie is klaarblyklik slegs ‘n gevolg van die spesiasie proses.

Thesis (Ph.D.)--Boston University
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Due to the direct magnetic connection of the high-latitude ionosphere to the outer magnetosphere, a great deal of knowledge of the physics and properties of magnetospheric regions and the fundamental plasma processes operating within them can be learned from studying low-altitude particle measurements. In this thesis the temporal and spatial aspects of the low-altitude auroral particle precipitation are investigated using a unique set of particle flux observations from two Defense Meteorological Satellite Program (DMSP) spacecraft in the same orbit but with varying time separation. Three different topics are investigated in this study: auroral stability, the accuracy of the Newell-Meng criteria for region identification, and the relative importance of various magnetopause reconnection models. In the first part the prevalent timescales and spatial dimensions of low-altitude auroral formations are examined using both electron and ion data. It is found that spatial scales larger than 50-100 km are stable for up to 1.5 minutes, while smaller size features vary more rapidly. In the second topic we explore quantitative and qualitative aspects of the Newell-Meng criteria. The flexibility and limitations of the numerical values used are examined with case and statistical studies; all but one are found to be sufficiently robust. Additionally, an expansion of the criteria to include a distinction between open and closed magnetic field line geometries is considered. The last part concentrates on the evaluation of currently proposed models of magnetopause reconnection, based on a case study of ion and electron low-altitude particle reconnection signatures. We conclude that a unique combination of the multiple x-line and bursty single x-line reconnection models is required for a full interpretation of the data. This scenario also provides a comprehensive mechanism for the formation of the low-latitude boundary layer on both open and closed field lines. Finally, the common conclusion of all three studies is that two-point measurements add considerably to our understanding of the low-altitude auroral environment and thereby, the remote processes governing its dynamics.
2031-01-01

Previous research has shown a close relationship between the terrestrial and aquatic carbon (C) cycles, namely that part of the C fixed via terrestrial net primary production (NPP) is exported to inland waters. In turn, it has been demonstrated that once in the freshwater system C can not only be transported laterally as dissolved organic carbon (DOC), particulate organic carbon (POC) and dissolved inorganic carbon (DIC) but is also mineralized and evaded back to the atmosphere as CO2, or buried in sediments. A number of hotspot areas of aquatic CO2 evasion have been identified but there are considerable gaps in our knowledge, particularly associated with understanding and accounting for the temporal and spatial variation of aquatic C fluxes at regional to global scales, which we know from local scale studies, to be substantial. In this thesis, three important regional hotspots of LOAC activity were identified, where significant gaps in our understanding remain.For the boreal region, an empirical model is developed to produce the first high resolution maps of boreal lake pCO2 and CO2 evasion, providing a new estimate for total evasion from boreal lakes of 189 (74–347) Tg C yr-1, which is more than double the previous best estimate. The model is also used along with future projections of terrestrial NPP and precipitation, to predict future lake CO2 evasion under future climate change and land-use scenarios, and it is found that even under the most conservative scenario CO2 evasion from boreal lakes may increase 38% by 2100. For the Amazon Basin, the ORCHILEAK land surface model driven by a newly developed wetland forcing file, is used to show that the export of C to and CO2 evasion from inland waters is highly interannually variable; greatest during wet years and lowest during droughts. However, at the same time overall net ecosystem productivity (NEP) and C sequestration is highest during wet years, partly due to reduced decomposition rates in water-logged floodplain soils. Furthermore, it is shown that aquatic C fluxes display greater variation than terrestrial C fluxes, and that this variation significantly dampens the interannual variability in NEP of the Amazon basin by moderating terrestrial variation. Finally, ORCHILEAK is applied to the Congo Basin to investigate the evolution of the integrated aquatic and terrestrial C fluxes from 1861 to the present day, and in turn to 2099 under a future climate and land-use scenario. It is shown that terrestrial and aquatic fluxes increase substantially over time, both over the historical period and into the future, and that these increases are largely driven by atmospheric CO2. The proportion of terrestrial NPP lost to the LOAC also rises from 3% in 1861 to 5% in 2099 and this trend is driven not only by atmospheric CO2 but also by climate change. This is in contrast to the boreal region where the proportion of NPP exported to inland waters is predicted to remain relatively constant, and to the Amazon, where a decrease has been predicted, due to differences in projected climate change.
L’état de l’art dans le domaine a montré qu’il y avait un lien étroit entre les cycles du carbone terrestre et aquatique :en effet, une partie du carbone fixé par photosynthèse (productivité primaire brute) est transférée vers les milieux aquatiques continentaux pour être ensuite transporté latéralement sous forme de carbone organique dissous (COD), de carbone organique particulaire (COP), de carbone inorganique dissous (CID). Durant ce transfert latéral, le carbone peut être minéralisé puis réémis vers l’atmosphère sous forme de CO2 ou enfoui dans les sédiments. Cependant, nous sommes encore loin de bien comprendre et surtout de quantifier les variations temporelles et spatiales des flux de carbones à l’échelle régionale et globale, même si les études faites à l’échelle locale nous montrent qu’elles sont importantes. Au cours de cette thèse, nous nous sommes focalisés sur 3 grandes régions pour lesquelles la connaissance des flux de carbone le long du continuum aquatique reliant les écosystèmes terrestres aux océans étaient encore très parcellaire.Pour la région boréale, un modèle empirique a été développé afin de produire les premières cartes à haute résolution de pCO2 et d’émission de CO2 pour les lacs boréaux. Les résultats du modèle nous ont permis de contraindre les émissions totales de CO2 pour les lacs boréaux à 189 (74-347) Tg C an-1, soit plus du double des estimations précédentes. Ce modèle a ensuite été couplé aux projections de production primaire brute terrestre et de précipitations afin de prédire les émissions de CO2 pour ces lacs pour différents scénarios de changement climatique et d’occupation des sols. Les résultats montrent que même en prenant le scénario le plus conservatif, les émissions de CO2 des lacs boréaux augmenteraient de 38% d’ici 2100.Pour le bassin de l’Amazone, le modèle d’écosystème terrestre ORCHILEAK, paramétré par de nouvelles donnés de forçage des zones humides, a été utilisé pour démontrer que l’export de carbone terrestre vers les réseaux fluviaux ainsi que les émissions de CO2 ont une très grande variabilité interannuelle :émissions élevées lors des années à forte précipitation et basses lors des années sèches. Cependant, la productivité nette de l’écosystème (PNE) Amazone et la fixation nette de carbone à l’échelle du bassin sont plus élevées lors des années humides, en partie dû au taux de décomposition de carbone organique réduit lorsque les sols sont saturés en eau. De plus, les résultats montrent que les flux de carbone des systèmes aquatiques ont une plus grande variabilité que les flux terrestres, ce qui atténue considérablement la variabilité interannuelle de la PNE du bassin de l'Amazone.Pour finir, nous avons appliqué ORCHILEAK au bassin du Congo afin d’étudier l’évolution intégrée des flux de carbone terrestres et aquatiques de 1861 à nos jours, ainsi que de projeter leur devenir au cours du 21eme siècle selon les scénarios de changement climatiques et de changement d’occupation des sols. Nous avons montré que les flux terrestres et aquatiques augmentent de façon significative durant la période historique et dans le futur, cette augmentation étant largement induite par l’augmentation du CO2 atmosphérique et, dans une moindre mesure, par le changement climatique. En particulier, la proportion de la productivité primaire brute terrestre exportée vers le continuum aquatique passe de 3% en 1861 à 5% en 2099. Ce résultat contraste avec ceux obtenu pour la région boréale où cette proportion reste relativement constante et pour l’Amazone où c’est une baisse qui est en fait prédite. Ces différences s’expliquent par des trajectoires de changement climatique distinctes pour ces 3 régions.
Doctorat en Sciences
info:eu-repo/semantics/nonPublished

Trabajo de Investigación Requisito para optar al Título de Cirujano Dentista
Introducción El análisis estético facial es utilizado como una importante herramienta clínica para el diagnóstico y tratamiento de las anomalías dentomaxilares. El Análisis Cefalométrico de Tejidos Blandos de William Arnett, ha sido ampliamente utilizado en la valoración estética de pacientes adultos desde el punto de vista ortodóncico y quirúrgico. La morfología facial en niños experimenta modificaciones al avanzar el crecimiento y desarrollo, estableciéndose variaciones en el perfil y proporciones faciales. Es por esto que los valores estéticos de perfil facial establecidos en adultos, no pueden aplicarse a pacientes pediátricos. El objetivo del estudio fue determinar parámetros estético faciales en pacientes pediátricos con dentición temporal completa y armonía facial, pertenecientes al área sur de la Región Metropolitana, según el análisis de William Arnett. Materiales y Métodos Un registro fotográfico estandarizado de perfil fue realizado a una muestra de 30 pacientes de 3 a 6 años de edad. Se aplicó el análisis de W. Arnett para las proyecciones a la línea vertical verdadera (LVV) y alturas faciales. El test-Student independiente se utilizó para comparar los valores promedios obtenidos entre géneros y comparar con los valores propuestos para adultos. Resultados Valores promedios se establecieron para las proyecciones a la LVV y alturas faciales en pacientes con dentición temporal completa. No se encontraron diferencias significativas entre géneros para las proyecciones a la LVV. La altura del Labio superior fue significativamente mayor en niños que en niñas. Se encontraron diferencias estadísticas entre niños(as) con dentición temporal completa y los valores determinados por W. Arnett para adultos, en todas las proyecciones a la LVV y alturas faciales, excepto el punto Labio superior y punto B’ en el género masculino y el punto A’ en el género femenino. Conclusiones Para evaluar el perfil facial de tejidos blandos en pacientes pediátricos, es necesario contar con valores de referencia propios para este grupo etáreo. Los valores obtenidos debiesen ser considerados en la valoración del crecimiento y desarrollo de pacientes pediátricos desde el punto de vista de la configuración de un perfil facial armónico. Esta metodología le permitirá al clínico realizar una evaluación objetiva y precoz de posibles alteraciones, facilitando el establecimiento de un diagnóstico y plan de tratamiento temprano.