Academic literature on the topic 'Detector species'

Bat surveys are frequently undertaken using ultrasonic detectors to determine the species present in an area on the basis of the identity of echolocation calls. We compared three techniques for using the Anabat II detector: the detector pointed along tracks (flyways) versus the detector pointed across tracks (non-flyways); recording output to audio cassette (analogue) versus direct recording to computer (digital); and active hand-held recording versus static automatic recording. In addition, we derived a species-accumulation curve from all-night Anabat recordings in the wet–dry tropics of the Northern Territory. We found no significant difference between flyway and non-flyway recordings; significantly more calls were identified from digital recordings; and significantly more species were detected using hand-held than static recordings. Species-accumulation analysis suggests that the minimum time required to achieve a satisfactory (80%) inventory of bat species at a site is during the three-hour period immediately after sunset. We use our findings to make recommendations for the design of bat surveys using the Anabat II detector.

ABSTRACT A two-probe proximal chaperone detection system consisting of a species-specific capture probe for the microarray and a labeled, proximal chaperone probe for detection was recently described for direct detection of intact rRNAs from environmental samples on oligonucleotide arrays. In this study, we investigated the physical spacing and nucleotide mismatch tolerance between capture and proximal chaperone detector probes that are required to achieve species-specific 16S rRNA detection for the dissimilatory metal and sulfate reducer 16S rRNAs. Microarray specificity was deduced by analyzing signal intensities across replicate microarrays with a statistical analysis-of-variance model that accommodates well-to-well and slide-to-slide variations in microarray signal intensity. Chaperone detector probes located in immediate proximity to the capture probe resulted in detectable, nonspecific binding of nontarget rRNA, presumably due to base-stacking effects. Species-specific rRNA detection was achieved by using a 22-nt capture probe and a 15-nt detector probe separated by 10 to 14 nt along the primary sequence. Chaperone detector probes with up to three mismatched nucleotides still resulted in species-specific capture of 16S rRNAs. There was no obvious relationship between position or number of mismatches and within- or between-genus hybridization specificity. From these results, we conclude that relieving secondary structure is of principal concern for the successful capture and detection of 16S rRNAs on planar surfaces but that the sequence of the capture probe is more important than relieving secondary structure for achieving specific hybridization.

The rate estimation of nuclear reactions induced in high intensity laser-target interaction (≥1016 W/cm2), is strongly depending on the neutron detection efficiency and ion charge discrimination, according to particles involved in exit open-channels. Ion discrimination is basically performed by means of analysis of pits observed on track detector, which is critically dependent on calibration and/or fast TOF devices based on SiC and diamond detectors. Last setup is used to determine the ion energy and to obtain a rough estimation of yields. However, for each TOF interval, the dependence of yield from the energy deposited in the detector sensitive region, introduces a distortion in the ion spectra. Moreover, if two ion species are present in the same spectrum, the discrimination of their contribution is not attainable. In this paper a new method is described which allows to discriminate the contribution of two ion species in the wide energy range of nuclear reactions induced in laser-target interactions. The method is based on charge response of two TOF-SiC detectors, of suitable thicknesses, placed in adjacent positions. In presence of two ion species, the response of the detectors, associated with different energy losses, can determine the ion specific contribution to each TOF interval.

Abstract This study is focused on an important family of the sage (Salvia) species, with Salvia officinalis L. having a long-established position in European traditional medicine. Binary fingerprints (chromatographic profiles) of six different sage species were compared using HPLC coupled with two different detectors: the diode-array detector and the evaporative light-scattering detector. Advantages of using binary fingerprinting over single-detector fingerprinting are demonstrated and discussed, with selected examples. Experimental data are provided for a comparison of the chemical composition of sage samples originating from two harvesting seasons (2007 and 2008). A number of phytochemical standards (i.e., certain phenolic acids, flavonoids, and coumarin) were used that allowed identification and semiquantitative estimation of these particular compounds in the analyzed methanol extracts.

Abstract Ultrasonic detectors are powerful tools for the study of bat ecology. Many options are available for deploying acoustic detectors including various weatherproofing designs and microphone orientations, but the impacts of these options on the quantity and quality of the bat calls that are recorded are unknown. We compared the impacts of three microphone orientations (horizontal, 45°, and vertical) and two weatherproofing designs (polyvinyl chloride tubes and the BatHat) on the number of calls detected, call quality, and species detected by the Anabat II bat detector system at 17 sites in central Kentucky in May and June 2008. Detectors with BatHat weatherproofing recorded significantly fewer call sequences, pulses per file, species per site, and lower quality calls. Detectors in the horizontal position also tended to record fewer files, fewer species, and lower quality calls. These results illustrate potential impacts of deployment method on quality and quantity of data obtained. Because weatherproofing and orientation impacted the quality and quantity of data recorded, comparison of results using different methodologies should be made with caution.

Obtaining adequate information for informed conservation-management decisions requires effective and cost-efficient survey techniques. We compared the effectiveness of bat detectors and harp traps for surveying bat assemblages within an urban landscape in Brisbane, Australia, with respect to number and composition of species. Nine sites within each of three habitat types (remnant bushland, parkland, and low-density residential – a total of 27 sites) were sampled twice each. The bat detectors recorded 3628 calls, from which 13 taxa were identified. The harp traps captured 17 individuals, from which five taxa were identified. All species captured by harp trap were also detected by bat detector, with the possible exception of N. bifax. Bat detectors recorded significantly more species per site than were captured by harp traps, both overall and within each of the three habitat types. And although a considerable amount of time and expense was required to identify the recorded echolocation calls to species, bat detectors were also the most cost-efficient sampling method. These results collectively show that bat detectors were the most effective and cost-efficient method for surveying the bat assemblage in this urban landscape.

Abstract Gradient elution HPLC was applied to develop fingerprints of 12 extracts obtained from selected mint species. The gradient was optimized by use of Merck ChromSword computer software on the basis of retention data of some standard compounds occurring in the investigated plant material. Two column types (RP18 and pentafluorophenyl) and two mobile phases (methanol–water and acetonitrile–water) were used during the experiments. Fingerprints of all extracts were generated, and on the basis of the fingerprints identification of the mints was possible.

Although protected areas have been used as principal conservation tools, most of them are suffering from human-induced threats. Consequently, a good understanding of such human-driven threats on biodiversity and identifying early warning systems for habitat change in protected areas is necessary for effective conservation of natural resources. To examine the impact of human disturbance on avifaunal assemblages and to assess the potential application of birds as bioindicators of forest health monitoring in the Afromontane forest of the Bale Mountains of Ethiopia, I recorded birds and habitat variables in three protected and three unprotected forests using a point transect method in 2009 and 2012. The two land use types differ in disturbance levels (higher in the unprotected areas), vegetation structure and bird assemblages. Species richness of entire bird guild, open woodland and open land habitat guilds, granivore and insectivore feeding guilds, and shrub layer and ground layer foraging substrate guilds of birds were significantly higher in the unprotected areas than the protected areas. Abundances of guilds of birds mostly followed a similar trend with species richness. However, densities of overall and forest-specialist bird guilds were higher in the protected area and vice versa for the other guilds. In general, the protected area assemblages were dominated by forest-specialist species, while those of the unprotected areas were dominated by openland and shrubland species. The implication is that disturbance had caused encroachment of non-native species (openland, open woodland and shrub land species) while negatively affecting native species (forest species, particularly tree canopy foragers). These assemblage differences are linked to changes in vegetation structure caused by disturbance. Thus, further forest degradation in the protected area should be avoided in order to maintain native/forest-specialist species. Given the differences in bird assemblages between the two land use types, there is a high likelihood that bioindicator species (i.e. indicator species - those 'characteristic' of a particular habitat - and detector species - those occurring in the different habitats considered but with moderate indication value) can be identified, therefore providing a useful tool to monitor ecosystem health of the forests. Four and nine species were identified as appropriate indicator species (i.e. species with indicator values > 60% and fulfilling biological and niche history criteria used in selection) in the protected and unprotected areas, respectively. In addition, nine species were identified as detectors of habitat change in the protected areas. These bioindicators provide a useful tool for managers of Afromontane forest in the Bale Mountains, as well as similar habitats elsewhere, for long term monitoring of ecosystem health of the forests.
Dissertation (MSc)--University of Pretoria, 2013.
DST/NRF Centre of Excellence
Zoology and Entomology
MSc
Unrestricted

I utilized a design science approach to create an automated kiosk that uses embodied intelligent agents to interview individuals and detect changes in arousal, behavior, and cognitive effort by using psychophysiological information systems. This dissertation achieves three primary purposes.First, I describe the creation of this new Information Technology artifact, discuss design choices, and show the completed prototype.Second, related to this new system, I propose a unique class of intelligent agents, which are described as Special Purpose Embodied Conversational Intelligence with Environmental Sensors (SPECIES). I outline a system model that frames the conceptual components of SPECIES agents, provide design principles for developing SPECIES agents, and discuss some of the research implications of the various components in the model.Third, based on the SPECIES paradigm, I present five studies that evaluate different parts of the model. These studies form the foundational research for the development of the automated kiosk. In the first study, participants interacted with an automated interviewing agent via a chat-based modality (108 participants). The study clearly demonstrates the strong, positive correlation of both response time and the number of times a message is edited to deceitful responses. The software developed became the heart of the kiosk. The second study evaluated changing human decision-making by including influence tactics in decision aids (41 participants). This paper-based decision experiment showed that framing decision aids as appeals to individuals' values possibly change individuals' decisions and was the basis for study 4. The third study examined human-computer interaction and how SPECIES agents can change perceptions of information systems by varying appearance and demeanor (88 participants). Instantiations that had the agents embodied as males were perceived as more powerful, while female embodied agents were perceived as more likeable. Similarly, smiling agents were perceived as more likable than neutral demeanor agents. The fourth study assessed how incorporating impression management techniques into embodied conversational agents can influence human perceptions of the system (88 participants). The impression management techniques proved to be very successful in changing user perceptions. Specifically, agents that performed self-promotion were perceived as more powerful, trustworthy and expert. Agents that performed ingratiation were perceived as more attractive. In the fifth study, I used an embodied agent to interview people who had either constructed a fake bomb and packed it into a bag or had only packed clothes into a bag (60 participants). The agent used eye-tracking technology to capture pupil dilation and gaze behavior. When combined with vocal measurements, the kiosk technology was able to achieve over 93% accuracy in one trial.

The identification and classification of yeasts has been based on morphological, physiological and biochemical properties. In recent years, different molecular biological techniques have been developed for yeast identification. A simple �·widely used but sUfficiently sensitive method is restriction analysis of amplified fragments (PCR-RFLP). Previous studies have produced reference records for Candida species and other yeast. However this reference library is not complete. In this study, PCR using ITS1 and ITS4 primers to amplify the ITS1, ITS2 and the 5.88 rRNA gene, and RFLP using C'ol, Haelll and Hinfl were used with 19 yeasts isolated from 21 soil and grass samples. Among these yeasts, PCR products varied between 400 bp to 650 bp. The restriction patterns could not all be identified due to limitations in the siz~ of the reference . database. Real-time PCRbased methodology has proved to be a sensitive detection system to both identify and quantify the level of microorganisms. In this study, real-time PCR using the F152 and R152 primer pair, targeting amplification of the 188 rONA, allowed for the differentiation of Candida and Saccharomyces, based on the Tm peak of the resultant products whilst the sensitivity of real-time PCR was as low as 500 femtogram of DNA whereas the sensitivity of conventional PCR was 500 picogram of DNA. Real-time PCR could be used to rapidly detect the presence of Candida species in environmental samples to a concentration of approximately 5 cellslcm3 �� The real-time PCR assay described detects Candida species in about 3 hours, which is faster than conventional culture methods. DNA isolation kits proved to be able to get rid of inhibitors in dirty samples but also inhibit the probe function in this study. The kits were only applicable for use with SYBR Green assay. By using DNA isolation kits, there were less positive real-time PCR results for Candida than cultivation followed by manual DNA extraction methodology. This investigation illustrates that the Tm values from SYBR Green assay may act as useful screening technique for Candida identification. The Cp value from probe assay is a confirmation technique as Cp values above 24 can be eliminated. The samples with Cp values below 24 were iden.tified as Candida species whilst those with Cp values above 24 were identified as other yeasts. PCR-RFLP can be used as an identification method for a number of Candida species but for Candida albicans and Candida tropicalis the results are inconclusive. Candida albicans and Candida tropicalis cannot be distinguished by RFLP or real-time PCR whilst morphological test such as germ tube production were also inclusive. However, sequence results clearly distinguished between these two species.

The importance of single-tree-based information for forest management and related industries in countries like Sweden, which is covered in approximately 65% by forest, is the motivation for developing algorithms for tree detection and species identification in this study. Most of the previous studies in this field are carried out based on aerial and spectral images and less attention has been paid on detecting trees and identifying their species using laser points and clustering methods. In the first part of this study, two main approaches of clustering (hierarchical and K-means) are compared qualitatively in detecting 3-D ALS points that pertain to individual tree clusters. Further tests are performed on test sites using the supervised k-means algorithm in which the initial clustering points are defined as seed points. These points, which represent the top point of each tree are detected from the cross section analysis of the test area. Comparing those three methods (hierarchical, ordinary K-means and supervised K-means), the supervised K-means approach shows the best result for clustering single tree points. An average accuracy of 90% is achieved in detecting trees. Comparing the result of the thesis algorithms with results from the DPM software, developed by the Visimind Company for analysing LiDAR data, shows more than 85% match in detecting trees. Identification of trees is the second issue of this thesis work. For this analysis, 118 trees are extracted as reference trees with three species of spruce, pine and birch, which are the dominating species in Swedish forests. Totally six methods, including best fitted 3-D shapes (cone, sphere and cylinder) based on least squares method, point density, hull ratio and slope changes of tree outer surface are developed for identifying those species. The methods are applied on all extracted reference trees individually. For aggregating the results of all those methods, a fuzzy logic system is used because of its good reputation in combining fuzzy sets with no distinct boundaries. The best-obtained model from the fuzzy system provides 73%, 87% and 71% accuracies in identifying the birch, spruce and pine trees, respectively. The overall obtained accuracy in species categorization of trees is 77%, and this percentage is increased dealing with only coniferous and deciduous types classification. Classifying spruce and pine as coniferous versus birch as deciduous species, yielded to 84% accuracy.

The detection and identification of bio-threat agents and study of host-pathogen interactions require a high-resolution detection platform capable of discerning closely related species. This dissertation addresses the completion of the development of an array based platform and provides a robust pipeline for the discovery of unique bio-signatures for pathogens and their host. Our collection (library) of host and pathogen signatures has been greatly expanded to improve robustness and identification accuracy of an 'unknown' sample. The library containing measured bio-signatures for each species/isolate is complemented with computational methodologies to resolve the identity of the unknown sample as well as a mixture of organisms or a pathogen in a host background. Current approaches for pathogen detection rely on prior genomic sequence information. This research targets use of a broad based platform for identification of pathogens from field or laboratory samples on a high density Universal Bio-signature Detection Array (UBDA). This array is genome independent and contains all possible (49 combinations) 9-mer probes which are mathematically computed and genome independent. It works by comparing signal intensity readout to a library of readouts established by interrogating a wide spectrum of organisms. Each genome has a unique pattern of signal intensities corresponding to each of these probes. These signal intensities were used to generate un-biased cluster analysis patterns that can easily distinguish organisms into accepted and known phylogenomic relationships. Classification methods such as hierarchical clustering, Pearsonâ s correlation matrix, principal component analysis and curve fitting regression methods were tested for pathogen specific use cases. Hierarchical clustering and Pearsonâ s correlation matrix methods can establish phylogenomic relationships between highly diverse genomes. However, in order to assign a given sample to one or more groups, such as a pure isolate of a single species or composite mixture of multiple species, principal component analysis (PCA) was used. The test cases included identification of mixed samples, case study of field samples from state diagnostic labs and finally a surveillance method for viral and parasite carrying insect host vectors. Completion of these application challenges is meant to demonstrate the power and confirm confidence in the Universal Bio-signature Detection Array.
Ph. D.

Les activités anthropiques causent des invasions biologiques qui sont devenues un problème mondial susceptible de causer des dommages écologiques (p. ex., sur la biodiversité et l’habitat), économiques (sur les industries) et sociaux (sur le bien-être humain). La prévention et la détection précoce des nouvelles invasions sont des éléments essentiels pour la gestion des risques et des impacts sur les écosystèmes et les économies. Bien sûr, la prévention est préférable, mais la détection précoce est une étape cruciale pour enrayer la propagation ultérieure des espèces envahissantes, car elle offre la possibilité de les éradiquer avant les phases d’établissement de la population et de propagation. Bien qu’il s’agisse d’une option de gestion efficace en matière de coût et de temps, la détection précoce exige un effort d’échantillonnage considérable pour détecter les populations envahissantes aux tout premiers stades de leur invasion. En utilisant le système benthique marin comme modèle, quatre études interdépendantes ont été menées pour identifier des stratégies d’échantillonnage susceptibles d’améliorer notre capacité à détecter des populations envahissantes rares et à comprendre les patrons et processus écologiques de recrutement benthique à multiples échelles spatiales et temporelles. Plus précisément, ces études expérimentales sur le terrain visaient à (1) évaluer la relation entre l’approvisionnement en larves et la fixation dans une population envahissante isolée, (2) déterminer la durée de l’échantillonnage et de la fréquence à l’aide de plaques de fixation pour la détection d’espèces rares, (3) déterminer l’importance relative aux sources de variations spatiales et temporelles du recrutement benthique, et (4) examiner l’effet de l’échelle spatiale de l’échantillonnage sur la détection des espèces en analysant les patrons de recrutement à de multiples échelles sur quatre ordres de grandeur allant de la dizaine de mètres à la dizaine de kilomètres. Première étude : contrairement à l’hypothèse originale d’une relation étroite entre l’approvisionnement et la fixation initiale, l’approvisionnement en larves était plutôt un facteur déterminant de la fixation aux échelles moyennes. Ces résultats suggèrent que la force de cette relation s’affaiblit avec l’augmentation de l’échelle spatiale des observations de terrain. Néanmoins, un quart de la variation de la fixation à moyenne échelle peut encore être expliqué par l’approvisionnement sur des courtes échelles de temps (une semaine). Par conséquent, cette relation confirme l’utilité des plaques de fixation en tant qu’outil efficace pour la détection précoce aux échelles moyennes dans une marina, car une faible densité de recrutement sur les plaques correspond à une faible abondance de propagules envahissantes dans la colonne d’eau...
Les activités anthropiques causent des invasions biologiques qui sont devenues un problème mondial susceptible de causer des dommages écologiques (p. ex., sur la biodiversité et l’habitat), économiques (sur les industries) et sociaux (sur le bien-être humain). La prévention et la détection précoce des nouvelles invasions sont des éléments essentiels pour la gestion des risques et des impacts sur les écosystèmes et les économies. Bien sûr, la prévention est préférable, mais la détection précoce est une étape cruciale pour enrayer la propagation ultérieure des espèces envahissantes, car elle offre la possibilité de les éradiquer avant les phases d’établissement de la population et de propagation. Bien qu’il s’agisse d’une option de gestion efficace en matière de coût et de temps, la détection précoce exige un effort d’échantillonnage considérable pour détecter les populations envahissantes aux tout premiers stades de leur invasion. En utilisant le système benthique marin comme modèle, quatre études interdépendantes ont été menées pour identifier des stratégies d’échantillonnage susceptibles d’améliorer notre capacité à détecter des populations envahissantes rares et à comprendre les patrons et processus écologiques de recrutement benthique à multiples échelles spatiales et temporelles. Plus précisément, ces études expérimentales sur le terrain visaient à (1) évaluer la relation entre l’approvisionnement en larves et la fixation dans une population envahissante isolée, (2) déterminer la durée de l’échantillonnage et de la fréquence à l’aide de plaques de fixation pour la détection d’espèces rares, (3) déterminer l’importance relative aux sources de variations spatiales et temporelles du recrutement benthique, et (4) examiner l’effet de l’échelle spatiale de l’échantillonnage sur la détection des espèces en analysant les patrons de recrutement à de multiples échelles sur quatre ordres de grandeur allant de la dizaine de mètres à la dizaine de kilomètres. Première étude : contrairement à l’hypothèse originale d’une relation étroite entre l’approvisionnement et la fixation initiale, l’approvisionnement en larves était plutôt un facteur déterminant de la fixation aux échelles moyennes. Ces résultats suggèrent que la force de cette relation s’affaiblit avec l’augmentation de l’échelle spatiale des observations de terrain. Néanmoins, un quart de la variation de la fixation à moyenne échelle peut encore être expliqué par l’approvisionnement sur des courtes échelles de temps (une semaine). Par conséquent, cette relation confirme l’utilité des plaques de fixation en tant qu’outil efficace pour la détection précoce aux échelles moyennes dans une marina, car une faible densité de recrutement sur les plaques correspond à une faible abondance de propagules envahissantes dans la colonne d’eau...
Les activités anthropiques causent des invasions biologiques qui sont devenues un problème mondial susceptible de causer des dommages écologiques (p. ex., sur la biodiversité et l’habitat), économiques (sur les industries) et sociaux (sur le bien-être humain). La prévention et la détection précoce des nouvelles invasions sont des éléments essentiels pour la gestion des risques et des impacts sur les écosystèmes et les économies. Bien sûr, la prévention est préférable, mais la détection précoce est une étape cruciale pour enrayer la propagation ultérieure des espèces envahissantes, car elle offre la possibilité de les éradiquer avant les phases d’établissement de la population et de propagation. Bien qu’il s’agisse d’une option de gestion efficace en matière de coût et de temps, la détection précoce exige un effort d’échantillonnage considérable pour détecter les populations envahissantes aux tout premiers stades de leur invasion. En utilisant le système benthique marin comme modèle, quatre études interdépendantes ont été menées pour identifier des stratégies d’échantillonnage susceptibles d’améliorer notre capacité à détecter des populations envahissantes rares et à comprendre les patrons et processus écologiques de recrutement benthique à multiples échelles spatiales et temporelles. Plus précisément, ces études expérimentales sur le terrain visaient à (1) évaluer la relation entre l’approvisionnement en larves et la fixation dans une population envahissante isolée, (2) déterminer la durée de l’échantillonnage et de la fréquence à l’aide de plaques de fixation pour la détection d’espèces rares, (3) déterminer l’importance relative aux sources de variations spatiales et temporelles du recrutement benthique, et (4) examiner l’effet de l’échelle spatiale de l’échantillonnage sur la détection des espèces en analysant les patrons de recrutement à de multiples échelles sur quatre ordres de grandeur allant de la dizaine de mètres à la dizaine de kilomètres. Première étude : contrairement à l’hypothèse originale d’une relation étroite entre l’approvisionnement et la fixation initiale, l’approvisionnement en larves était plutôt un facteur déterminant de la fixation aux échelles moyennes. Ces résultats suggèrent que la force de cette relation s’affaiblit avec l’augmentation de l’échelle spatiale des observations de terrain. Néanmoins, un quart de la variation de la fixation à moyenne échelle peut encore être expliqué par l’approvisionnement sur des courtes échelles de temps (une semaine). Par conséquent, cette relation confirme l’utilité des plaques de fixation en tant qu’outil efficace pour la détection précoce aux échelles moyennes dans une marina, car une faible densité de recrutement sur les plaques correspond à une faible abondance de propagules envahissantes dans la colonne d’eau. Deuxième étude : des durées d’échantillonnage intermédiaires d’une à deux semaines (l’échelle des traitements allant d’un jour à un mois) étaient la durée optimale de déploiement de la plaque de fixation pour la détection des espèces « rares » (c’est-à-dire, des le début du recrutement). Une analyse au niveau de l’assemblage montre toutefois que l’augmentation de la durée et de la fréquence de l’échantillonnage augmentait logarithmiquement le nombre total d’espèces rares observées. Ces résultats espèce par espèce et au niveau de l’assemblage démontrent que la modification des éléments temporels de l’échantillonnage, tels que la durée et la fréquence, peut affecter considérablement la détection d’espèces. Troisième étude : après avoir évalué plusieurs sources spatiales et temporelles (le site, la région, la saison, et l’année), le moment choisi pour le déploiement des plaques est apparu comme étant la plus grande source de variabilité du recrutement benthique d’espèces rares. En particulier, le moment optimal pour la détection précoce serait en automne (a) lorsque le recrutement saisonnier d’espèces envahissantes établies tend à atteindre un pic et (b) lorsque la détection au niveau du site d’espèces envahissantes rares tend à se produire. Quatrième étude : l’échelle spatiale dominante dans le recrutement d’espèces rares est la plus petite (centaine de mètres). Cette échelle dominante peut être interprétée comme étant la bonne échelle spatiale pour la détection d’espèces rares. Une analyse plus poussée a montré que si l’échantillonnage a été structuré de manière aléatoire, l’échantillonnage à des échelles intermédiaires (millier de mètres) devient l’échelle optimale pour la détection d’espèces rares. Ces résultats élucident les différences de variabilité naturelle de la population benthique entre multiples échelles d’espace et de temps pour des espèces rares et communes. Ces études écologiques font partie d’une boîte à outils de détection précoce nécessaire à la gestion des espèces envahissantes marines en renseignant sur la manière dont l’échantillonnage des espèces rares doit être faite à multiples échelles spatio-temporelles. Des expériences de terrain similaires optimisant la détection d’espèces rares (au-delà de l’utilisation de plaques de fixation pour détecter les organismes benthiques dans les provinces Maritimes canadiennes) devraient être réalisées pour d’autres taxons, régions, t outils d’échantillonnage—en particulier, les envahisseurs à haut risque prévus, les invasions futures, et les outils récemment développés.
Les activités anthropiques causent des invasions biologiques qui sont devenues un problème mondial susceptible de causer des dommages écologiques (p. ex., sur la biodiversité et l’habitat), économiques (sur les industries) et sociaux (sur le bien-être humain). La prévention et la détection précoce des nouvelles invasions sont des éléments essentiels pour la gestion des risques et des impacts sur les écosystèmes et les économies. Bien sûr, la prévention est préférable, mais la détection précoce est une étape cruciale pour enrayer la propagation ultérieure des espèces envahissantes, car elle offre la possibilité de les éradiquer avant les phases d’établissement de la population et de propagation. Bien qu’il s’agisse d’une option de gestion efficace en matière de coût et de temps, la détection précoce exige un effort d’échantillonnage considérable pour détecter les populations envahissantes aux tout premiers stades de leur invasion. En utilisant le système benthique marin comme modèle, quatre études interdépendantes ont été menées pour identifier des stratégies d’échantillonnage susceptibles d’améliorer notre capacité à détecter des populations envahissantes rares et à comprendre les patrons et processus écologiques de recrutement benthique à multiples échelles spatiales et temporelles. Plus précisément, ces études expérimentales sur le terrain visaient à (1) évaluer la relation entre l’approvisionnement en larves et la fixation dans une population envahissante isolée, (2) déterminer la durée de l’échantillonnage et de la fréquence à l’aide de plaques de fixation pour la détection d’espèces rares, (3) déterminer l’importance relative aux sources de variations spatiales et temporelles du recrutement benthique, et (4) examiner l’effet de l’échelle spatiale de l’échantillonnage sur la détection des espèces en analysant les patrons de recrutement à de multiples échelles sur quatre ordres de grandeur allant de la dizaine de mètres à la dizaine de kilomètres. Première étude : contrairement à l’hypothèse originale d’une relation étroite entre l’approvisionnement et la fixation initiale, l’approvisionnement en larves était plutôt un facteur déterminant de la fixation aux échelles moyennes. Ces résultats suggèrent que la force de cette relation s’affaiblit avec l’augmentation de l’échelle spatiale des observations de terrain. Néanmoins, un quart de la variation de la fixation à moyenne échelle peut encore être expliqué par l’approvisionnement sur des courtes échelles de temps (une semaine). Par conséquent, cette relation confirme l’utilité des plaques de fixation en tant qu’outil efficace pour la détection précoce aux échelles moyennes dans une marina, car une faible densité de recrutement sur les plaques correspond à une faible abondance de propagules envahissantes dans la colonne d’eau. Deuxième étude : des durées d’échantillonnage intermédiaires d’une à deux semaines (l’échelle des traitements allant d’un jour à un mois) étaient la durée optimale de déploiement de la plaque de fixation pour la détection des espèces « rares » (c’est-à-dire, des le début du recrutement). Une analyse au niveau de l’assemblage montre toutefois que l’augmentation de la durée et de la fréquence de l’échantillonnage augmentait logarithmiquement le nombre total d’espèces rares observées. Ces résultats espèce par espèce et au niveau de l’assemblage démontrent que la modification des éléments temporels de l’échantillonnage, tels que la durée et la fréquence, peut affecter considérablement la détection d’espèces. Troisième étude : après avoir évalué plusieurs sources spatiales et temporelles (le site, la région, la saison, et l’année), le moment choisi pour le déploiement des plaques est apparu comme étant la plus grande source de variabilité du recrutement benthique d’espèces rares. En particulier, le moment optimal pour la détection précoce serait en automne (a) lorsque le recrutement saisonnier d’espèces envahissantes établies tend à atteindre un pic et (b) lorsque la détection au niveau du site d’espèces envahissantes rares tend à se produire. Quatrième étude : l’échelle spatiale dominante dans le recrutement d’espèces rares est la plus petite (centaine de mètres). Cette échelle dominante peut être interprétée comme étant la bonne échelle spatiale pour la détection d’espèces rares. Une analyse plus poussée a montré que si l’échantillonnage a été structuré de manière aléatoire, l’échantillonnage à des échelles intermédiaires (millier de mètres) devient l’échelle optimale pour la détection d’espèces rares. Ces résultats élucident les différences de variabilité naturelle de la population benthique entre multiples échelles d’espace et de temps pour des espèces rares et communes. Ces études écologiques font partie d’une boîte à outils de détection précoce nécessaire à la gestion des espèces envahissantes marines en renseignant sur la manière dont l’échantillonnage des espèces rares doit être faite à multiples échelles spatio-temporelles. Des expériences de terrain similaires optimisant la détection d’espèces rares (au-delà de l’utilisation de plaques de fixation pour détecter les organismes benthiques dans les provinces Maritimes canadiennes) devraient être réalisées pour d’autres taxons, régions, t outils d’échantillonnage—en particulier, les envahisseurs à haut risque prévus, les invasions futures, et les outils récemment développés.
As a consequence of anthropogenic activities, biological invasions have become a global problem that can cause ecological (e.g., biodiversity and habitat), economic (industries), and social (human wellbeing) harm. Prevention and early detection of new invasions are vital components of managing risks and impacts to ecosystems and economies. Prevention is, of course, preferred but early detection is a critical step that can ultimately stop future spread of invasive species because it provides an opportunity for eradication before population growth and spread. Despite being a cost- and time-effective management option, early detection requires considerably high sampling effort to detect incipient invasive populations at the early stages of their invasion. Using the marine benthic system as a model, four inter-related studies were carried out to identify sampling strategies that could enhance our ability to detect rare invasive populations and to understand ecological patterns and processes of benthic recruitment across multiple scales of space and time. Specifically, these experimental field studies aimed to (1) evaluate the relationship between propagule supply and settlement in a closed invasive population, (2) determine the optimal sampling duration and frequency using settlement plates to detect rare species, (3) ascertain the relative importance of spatial and temporal sources of variation in benthic recruitment, and (4) examine how the spatial scale of sampling affects species detection by analyzing recruitment patterns at multiple scales across four orders of magnitudes ranging from tens of metres to tens of kilometres. First study: Contrary to the expectation of a strong relationship between supply and initial settlement, larval supply was instead a limited determinant of settlement at mesoscales. This finding suggests that the strength of this relationship weakens as the spatial scale increased from previously reported small-scale field observations to mesoscales of the present study. Nonetheless, a quarter of the variation in settlement can still be explained by supply over short timescales (one week). Therefore, this relationship supports the utility of settlement plates as an effective tool for early detection at mesoscales within a marina because low densities of recruitment on plates correspond to low abundances of invasive propagules in the water column...
As a consequence of anthropogenic activities, biological invasions have become a global problem that can cause ecological (e.g., biodiversity and habitat), economic (industries), and social (human wellbeing) harm. Prevention and early detection of new invasions are vital components of managing risks and impacts to ecosystems and economies. Prevention is, of course, preferred but early detection is a critical step that can ultimately stop future spread of invasive species because it provides an opportunity for eradication before population growth and spread. Despite being a cost- and time-effective management option, early detection requires considerably high sampling effort to detect incipient invasive populations at the early stages of their invasion. Using the marine benthic system as a model, four inter-related studies were carried out to identify sampling strategies that could enhance our ability to detect rare invasive populations and to understand ecological patterns and processes of benthic recruitment across multiple scales of space and time. Specifically, these experimental field studies aimed to (1) evaluate the relationship between propagule supply and settlement in a closed invasive population, (2) determine the optimal sampling duration and frequency using settlement plates to detect rare species, (3) ascertain the relative importance of spatial and temporal sources of variation in benthic recruitment, and (4) examine how the spatial scale of sampling affects species detection by analyzing recruitment patterns at multiple scales across four orders of magnitudes ranging from tens of metres to tens of kilometres. First study: Contrary to the expectation of a strong relationship between supply and initial settlement, larval supply was instead a limited determinant of settlement at mesoscales. This finding suggests that the strength of this relationship weakens as the spatial scale increased from previously reported small-scale field observations to mesoscales of the present study. Nonetheless, a quarter of the variation in settlement can still be explained by supply over short timescales (one week). Therefore, this relationship supports the utility of settlement plates as an effective tool for early detection at mesoscales within a marina because low densities of recruitment on plates correspond to low abundances of invasive propagules in the water column...

Phytophthora diseases have caused worldwide economic, social and environmental impacts for decades. Once their presence is confirmed, they are difficult to eradicate. To reduce and manage the damage inflicted by the pathogen, fast and reliable disease management protocols are required. Tests that enable the rapid and reliable identification of the pathogen assist greatly in disease management. Phytophthora species are traditionally not only detected by baiting but also by plating of symptomatic tissue on selective media. Species can be identified by the characteristics of the mycelium growing out of the bait. However, the method is low throughput, labour intensive, and prone to false negatives. An alternative approach would be to detect the pathogen by the presence of its DNA. This involves amplification of the pathogen DNA using Polymerase Chain Reaction (PCR) and detection of the amplification product. Detection is usually by agarose gel electrophoresis. However, this is also a labour intensive process involving pouring, loading, running, and staining of the gels. The aim of this thesis is to explore the use of Matrix Assisted Laser Desorption/ Ionisation Time-of-Flight (MALDI-TOF) mass spectrometry for detection of PCR products. This procedure enables the analysis of large numbers of samples within a very short time-frame as the average time for analysis of each sample is in the order of milliseconds. The assay involves annealing an extension (genotyping) primer to the PCR product and its extension by a single nucleotide. The nature of the nucleotide added differentiates species as does the site to which the primer anneals. Multiple extension (genotyping) primers can be used together in a single reaction for detection of multiple species. In this project four genotyping primers (GPs) were designed from the ITS regions of Phytophthora palmivora, Phytophthora cinnamomi, Phytophthora citricola, and Phytophthora cambivora. The extension primers were tested for their specificity on the DNA of the target species. The four primers designed were specific for their intended targets except for GPpalm3 which in addition to being extended by ddT when tested with DNA from P. palmivora, was also extended by ddC when tested with DNA from other species of Phytophthora or Pythium. These primers were also tested for their ability to detect multiple Phytophthora species in a single reaction (multiplexing). Mixtures of primers were added to mixed DNA templates and the primer extension reaction carried out. The primers were designed so that their masses were sufficiently different for them to be identified from a mixture. Six replicates were analysed for each reaction. In general only about 1-3 of the six replicates gave a positive reaction. This indicates that there may be some interference between primers, or that the presence of all four nucleotides interfered with the primer extension reaction. Increasing either the amount of enzyme, the amount of nucleotides or both did not improve the results. The sensitivity of detection was tested by the addition of different amounts of mycelium to soil. The detection sensitivity depended on the primer pair used for PCR amplification. The ITS1/2 primer pair was more sensitive than the ITS1/4 pair. The limit of detection was 1 ìg mycelium g soil-1. However using nested PCR, levels of sensitivity comparable to those obtained using the ITS1/2 primer pair could be achieved. Primers to other regions of the genome such as the beta cinnamomin elicitin gene gave very low levels of sensitivity compared to the ITS primers. In comparison with DNA detection we found that the limit of detection using baiting was 4 ìg mycelium g soil-1. Results below this limit were unreliable. The method suffered from the additional disadvantage that it took a long time in comparison to DNA detection. DNA detection methods do not distinguish between living and dead organisms in the soil. However it can be hypothesised that DNA is unlikely to persist for any significant length of time in soil. To test this, we added plasmid DNA to soil and tested the persistence of this DNA using a variety of methods such as precipitation of labelled DNA, southern blotting and PCR amplification. It was found that in general, in soils from different ecosystems, the bulk of the DNA was undetectable after 24 hours. The rate of DNA breakdown differed with the soil type. In some soils, the added DNA was not detected even after 2 hours, whereas in others it could be observed after 10 hours. The detection depended on the method. Southern blotting showed that although DNA could be observed at 10 hours, by 24 hours it was completely degraded. In contrast a PCR product could be obtained from the soil extracts up to 24 hours. In a separate experiment, plasmid DNA was detectable over a 24 hour incubation period in 5 soil samples from 5 different sites. The results suggest that DNA is degraded rapidly in soil and is unlikely to persist longer than 24 hours. The results in this thesis demonstrate that MALDI-TOF MS is a suitable alternative to agarose gel electrophoresis for analysis of PCR products. The technique is rapid, differentiates species from mixtures, is high-throughput and amenable to automation. Implementation will require further research to automate the primer extension assay to reduce the sensitivity to impurities in the DNA and to design parameters for sampling asymptomatic material.

Phytophthora diseases have caused worldwide economic, social and environmental impacts for decades. Once their presence is confirmed, they are difficult to eradicate. To reduce and manage the damage inflicted by the pathogen, fast and reliable disease management protocols are required. Tests that enable the rapid and reliable identification of the pathogen assist greatly in disease management. Phytophthora species are traditionally not only detected by baiting but also by plating of symptomatic tissue on selective media. Species can be identified by the characteristics of the mycelium growing out of the bait. However, the method is low throughput, labour intensive, and prone to false negatives. An alternative approach would be to detect the pathogen by the presence of its DNA. This involves amplification of the pathogen DNA using Polymerase Chain Reaction (PCR) and detection of the amplification product. Detection is usually by agarose gel electrophoresis. However, this is also a labour intensive process involving pouring, loading, running, and staining of the gels. The aim of this thesis is to explore the use of Matrix Assisted Laser Desorption/ Ionisation Time-of-Flight (MALDI-TOF) mass spectrometry for detection of PCR products. This procedure enables the analysis of large numbers of samples within a very short time-frame as the average time for analysis of each sample is in the order of milliseconds. The assay involves annealing an extension (genotyping) primer to the PCR product and its extension by a single nucleotide. The nature of the nucleotide added differentiates species as does the site to which the primer anneals. Multiple extension (genotyping) primers can be used together in a single reaction for detection of multiple species. In this project four genotyping primers (GPs) were designed from the ITS regions of Phytophthora palmivora, Phytophthora cinnamomi, Phytophthora citricola, and Phytophthora cambivora. The extension primers were tested for their specificity on the DNA of the target species. The four primers designed were specific for their intended targets except for GPpalm3 which in addition to being extended by ddT when tested with DNA from P. palmivora, was also extended by ddC when tested with DNA from other species of Phytophthora or Pythium. These primers were also tested for their ability to detect multiple Phytophthora species in a single reaction (multiplexing). Mixtures of primers were added to mixed DNA templates and the primer extension reaction carried out. The primers were designed so that their masses were sufficiently different for them to be identified from a mixture. Six replicates were analysed for each reaction. In general only about 1-3 of the six replicates gave a positive reaction. This indicates that there may be some interference between primers, or that the presence of all four nucleotides interfered with the primer extension reaction. Increasing either the amount of enzyme, the amount of nucleotides or both did not improve the results. The sensitivity of detection was tested by the addition of different amounts of mycelium to soil. The detection sensitivity depended on the primer pair used for PCR amplification. The ITS1/2 primer pair was more sensitive than the ITS1/4 pair. The limit of detection was 1 mcg mycelium g soil-1. However using nested PCR, levels of sensitivity comparable to those obtained using the ITS1/2 primer pair could be achieved. Primers to other regions of the genome such as the beta cinnamomin elicitin gene gave very low levels of sensitivity compared to the ITS primers. In comparison with DNA detection we found that the limit of detection using baiting was 4 mcg mycelium g soil-1. Results below this limit were unreliable. The method suffered from the additional disadvantage that it took a long time in comparison to DNA detection. DNA detection methods do not distinguish between living and dead organisms in the soil. However it can be hypothesised that DNA is unlikely to persist for any significant length of time in soil. To test this, we added plasmid DNA to soil and tested the persistence of this DNA using a variety of methods such as precipitation of labelled DNA, southern blotting and PCR amplification. It was found that in general, in soils from different ecosystems, the bulk of the DNA was undetectable after 24 hours. The rate of DNA breakdown differed with the soil type. In some soils, the added DNA was not detected even after 2 hours, whereas in others it could be observed after 10 hours. The detection depended on the method. Southern blotting showed that although DNA could be observed at 10 hours, by 24 hours it was completely degraded. In contrast a PCR product could be obtained from the soil extracts up to 24 hours. In a separate experiment, plasmid DNA was detectable over a 24 hour incubation period in 5 soil samples from 5 different sites. The results suggest that DNA is degraded rapidly in soil and is unlikely to persist longer than 24 hours. The results in this thesis demonstrate that MALDI-TOF MS is a suitable alternative to agarose gel electrophoresis for analysis of PCR products. The technique is rapid, differentiates species from mixtures, is high-throughput and amenable to automation. Implementation will require further research to automate the primer extension assay to reduce the sensitivity to impurities in the DNA and to design parameters for sampling asymptomatic material.

AbstractGamma radiation detection finds many applications in different fields, including astrophysics, nuclear physics and medical diagnostics. Nowadays large Lanthanum Bromide crystals coupled to Photomultiplier Tubes (PMTs) represent the state of the art for gamma detection modules, in particular for spectroscopic measurements. Nevertheless, there is an interest in substituting photomultiplier tubes with solid state photodetectors like Silicon Photomultipliers (SiPMs), owing to the latter’s significant advantages. These include insensitivity to magnetic fields, low bias voltage, compactness, fast response and mechanical robustness. The aim of this thesis work, which was carried out within the context of the GAMMA project supported by IstitutoNazionale di FisicaNucleare (INFN), is the design, development and experimental characterization of a -ray spectrometer based on large Lanthanum Bromide scintillator crystals coupled with Silicon Photomultipliers. This detector specifications are compliant with nuclear physics experiments with energies ranging from 100 keV to 20 MeV, characterized by state-of-the-art energy resolution and imaging capability, in a compact, modular and robust structure. In order to perform the readout of large scintillator crystals, a matrix of 144 Silicon Photomultipliers was designed using NUV-HD SiPMs from Fondazione Bruno Kessler (FBK). These were chosen due to their high Photon Detection Efficiency in correspondence with the peak emission wavelength of the crystal, the high cell density and low Dark Count Rate.

AbstractManaging invasive species becomes increasingly difficult and expensive as populations of new pathogens, plants, insects, and other animals (i.e., pests) spread and reach high densities. Research over the past decade confirms the value of early intervention strategies intended to (1) prevent invasive species from arriving within an endangered area or (2) detect and respond quickly to new species incursions (Baker et al. 2009; Ewel et al. 1999; Holden et al. 2016; Leung et al. 2014). The goal of such biosecurity approaches is to keep or return the density of invasive species to zero so that damages from those pests might be prevented or to confine populations to localized areas so that damage from those species might be limited (Magarey et al. 2009). Prediction, prevention, early detection, eradication, and other rapid responses, all components of proactive management, are less costly and more effective than reactive tactics (Epanchin-Niell and Liebhold 2015; Leung et al. 2002; Lodge et al. 2006; Rout et al. 2014) (Fig. 6.1). Prediction is achieved through risk assessment (a process to forecast the likelihood and consequence of an invasion) and pathway analysis (a process to evaluate the means by which invasive species might be brought into an area of concern). Prevention is achieved through a variety of measures including regulations and quarantine treatments. Indeed, pathway analyses and subsequent regulation of those pathways are considered “the frontline in the prevention of biological invasions” (Hulme 2009) and cost-effective approaches (Essl et al. 2015; Keller et al. 2007; Leung et al. 2002; Tidbury et al. 2016). Surveillance is fundamental to early detection, and if a target species is detected, the primary rapid responses are eradication, containment, or suppression (reviewed in Beric and MacIsaac 2015). Early intervention strategies often operate at spatial scales that are much greater than the scale at which most land managers operate. Success thus requires effective coordination among researchers, regulators, and managers at international, national, sub-national, and local levels.

AbstractThe spread of invasive alien species (IAS) is recognized as the most severe threat to biodiversity outside of climate change and anthropogenic habitat destruction. IAS negatively impact ecosystems, local economies, and residents. They are especially problematic because once established, they give rise to positive feedbacks, increasing the likelihood of further invasions and spread. The integration of remote sensing (RS) to the study of invasion, in addition to contributing to our understanding of invasion processes and impacts to biodiversity, has enabled managers to monitor invasions and predict the spread of IAS, thus supporting biodiversity conservation and management action. This chapter focuses on RS capabilities to detect and monitor invasive plant species across terrestrial, riparian, aquatic, and human-modified ecosystems. All of these environments have unique species assemblages and their own optimal methodology for effective detection and mapping, which we discuss in detail.

Abstract This chapter includes information on: authentic identification; geographical distribution; risk of introduction; host ranges; symptoms; biology and ecology; planting material liable to carry the nematode; chance of establishment; likely impact; phytosanitary measures; and a detailed account of diagnosis procedures, such as sampling, isolation/detection and identification with morphological and molecular characterization, of invasive plant-parasitic Meloidogyne species.

Abstract This chapter includes information on: authentic identification; geographical distribution; risk of introduction; host ranges; symptoms; biology and ecology; planting material liable to carry the nematode; chance of establishment; likely impact; phytosanitary measures; and a detailed account of diagnosis procedures, such as sampling, isolation/detection and identification with morphological and molecular characterization, of the species of the invasive plant-parasitic sheath nematode Hemicycliophora.

A low-background gamma spectrometer consists of a high-performance gamma detector and a low-background chamber. It is widely used to monitor the radiation level of the environment and to identify the species of the radiological source. It is especially important for the analysis of the nuclear accident. Usually a high purity Germanium detector (HPGe) is used as a gamma ray detector. In order to enhance the detecting accuracy and sensitivity, it is essential to improve the performance of the gamma detector. In recent years, a clover detector composed of four coaxial HPGe crystals appear and is widely utilized in nuclear physics experimental research. Because of the larger dimensions and segmented structure, it displays outstanding characteristics different from traditional HPGe detectors. With a clover detector as the main detector and the HPLBS1 chamber of ORTEC as the lead chamber, the low-background gamma spectrometer is simulated by the Monte Carlo toolkit GEANT4, where the interaction processes of gamma ray provided by the GEANT4 physics list is used. The detecting performance of the low-background gamma spectrometer such as detecting efficiency and peak-total ratio are given. The results indicate that low-background gamma spectrometer with a clover as the main detector has better characteristic than that with HPGe as a main detector traditionally.

An undiluted exhaust hydrocarbon (HC) speciation method, using flame ionization detector (FID) gas chromatographs (GC), is developed to investigate HC species from conventional and low-temperature premixed charge compression ignition (PCI) combustion, from pre- and post-diesel oxidation catalyst (DOC) exhaust. This paper expands on previously reported work by describing in detail the method and effectiveness of undiluted diesel exhaust speciation and providing a more detailed analysis of individual HC species for conventional and PCI diesel combustion processes. The details provided regarding the effectiveness of the undiluted diesel exhaust speciation method include the use of a fuel response factor (RF) for HC species quantification and demonstration of its linearity, detection limit, accuracy and precision. The listing of individual HC species provides not only the information needed to design surrogate exhaust mixtures used in reactor tests and modeling studies, but also sheds light on PCI combustion and DOC characteristics. Significantly increased engine-out concentrations of acetylene, benzene and toluene support the theory that net soot reduction associated with PCI combustion occurs due to the reduction of soot formation from soot precursors. DOC oxidation behavior differs depending on the combustion characteristics, which change exhaust species and temperature.

In this study, the difference of temperature and the component of chemical species on soot formation in CH4/air fuel-rich diffusion flames were investigated. Furthermore, for decreasing soot formation in fuel-rich diffusion flames, we added H2 in CH4, investigated the property of combustion, and compared with methane/air fuel-rich flames. We have paid much attention to the influence of the equivalence ratio of methane (+H2)/air, the swirl strength of combustion air and the concentration of C2H2 on the soot formation. The experimental combustor for CH4(+H2)/air combustion was designed, and the soot resulting from the exhaust gas collected with a silica filter and its weight was measured. The microstructure of the soot particles were analyzed with a Scanning Electron Microscopy (SEM). The temperature profiles in the combustor were measured by thermocouples, and the concentrations of the species O2, CO2, H2, CH4 and C2H2 were determined by a TCD (thermal conductivity detector) gas chromatograph (GC) and FID (flame ionization detector) GC. The soot yields diminished with increasing swirl strength and the C2H2 concentration. When H2 was added to the fuel, combustion was promoted and C2H2 concentration in the exhaust gas was diminished. But using strong swirl, fuel and air were mixed quickly, the effect of H2 addition was decreased.

Tension metastable fluid states offer unique potential for radical transformation in radiation detection capabilities. States of tension metastability may be obtained in tailored resonant acoustic systems such as the acoustic tension metastable fluid detector (ATMFD) system or via centrifugal force based systems such as the centrifugal tension metastable fluid detector (CTMFD) system; both under development at Purdue University. Tension metastable fluid detector (TMFD) systems take advantage of the weakened intermolecular bonds of liquids in sub-vacuum states. Nuclear particles incident onto sufficiently tensioned fluids can nucleate critical size vapor bubbles which grow from nanoscales and are then possible to see, hear and record with unprecedented efficiency and capability [1]. Previous work by our group has shown the ability of TMFD systems to detect neutrons with energies spanning eight orders of magnitude with 95%+ intrinsic efficiency [2] while remaining insensitive to gamma photons and also giving directional information [3] on the source of the radiation. In this paper we describe research results with CTMFD systems for use in the detection of key actinide isotopes constituting special nuclear materials (SNMs) in spent fuel. Tests in a CTMFD system demonstrate the ability to detect alpha activity (at ∼100% efficiency) of U-isotopes at concentrations of ∼100 ppb (which is unprecedented and about x100–1000 more sensitive than from conventional liquid scintillation spectroscopy). An inherent capability of TMFD systems concerns on demand tailoring of fluid tension levels allowing for energy discrimination and spectroscopy. This appears especially useful to detect the key isotopes of U and other transuranic isotopes of Pu, Np, Am, and Cm that are at different stages of nuclear fuel reprocessing (i.e. UREX+).

Construction of Prototype Fast Breeder Reactor (PFBR) a 500 MWe pool type sodium cooled breeder reactor with MOX fuel has started at Kalpakkam. Instrumentation & Control (I&C) of PFBR is designed for safe, reliable and economic operation of the plant. Special feature of breeder reactors is sodium instrumentation. Leaks in sodium systems have the possibility of being exceptionally hazardous due to the reaction of liquid sodium with oxygen and water vapour in the air. In addition, leakage from primary systems can cause radioactive contamination. Potential regions of leakage are near welds and high stress areas. Sodium also reacts with concrete releasing hydrogen and leading to damage and loss of strength of concrete structures. Leaking sodium catches fire depending on its temperature. Sodium temperature in the plant ranges from 423 K at filling condition to 820 K at reactor nominal power operating condition. Leak detectors are provided on pipelines, tanks and other capacities. Sodium leak detection systems are designed to meet requirements of ASME section XI- division 3 which specifies that sodium leak at the rate of 100 g/h are to be detected in 20 h for air filled vaults and 250 h for inert vaults. Diverse leak detection methods are employed for active and non-active sodium equipment and pipes. For detection of water leaks into Sodium in steam generators, Hydrogen in Sodium Detectors (HSD) are used. Hydrogen in Argon Detectors (HAD) are used for sodium temperatures below 623 K as HSD is not effective below this temperature due to non-dissolution of hydrogen formed. Choice and challenges posed in implementation of above leak detection requirements are discussed in this paper.

Advancements in tension metastable fluid detector (TMFD) technology have led to an extension in detector sensitivity to now also detect and distinguish thermal energy (∼.02 eV) neutrons in addition to fast neutrons — spanning 109 orders of magnitude. The unique nature of detector operation and inherent detection mechanism in TMFDs offers a distinct advantage over conventional systems. TMFDs now posses the capabilities for simultaneous sensitivity to fast and thermal neutrons with high intrinsic efficiency, ascertaining directional and spectroscopic source information, all while remaining completely blind to background gamma and beta irradiation. The additional of thermal energy sensitivity was enabled via inclusion of boron in the detection fluid mixture; a compound composed of decaflouropentane (DFP), trimethyl borate (TMB) and methanol. Experimental benchmarking studies were conducted using the spontaneous fission based neutron source 252Cf, in conjunction with theoretical assessments using the nuclear particle transport package MCNP. Source neutron thermalization was accomplished through submersion of the source in a block of ice, such that the moderated spectrum contained an approximate 1:1 ratio between the fast and thermal flux magnitudes. Experimental results show that borated detection fluids yielded up to 6x improvements in the detection rate over their non-borated counterparts. Implications of the current results in regards to the applicability of TMFDs in the field of special nuclear material (SNM) interrogation and detection are discussed.

Extensively released hydrogen due to zirconium-water reaction during severe accidents in containment of pressurized water reactor raises explosion crisis. Since the containment is the last barrier for fatal irradiation species, efficient measures should be implemented to restrain the hydrogen. Hence, hydrogen elimination and monitor devices are wildly applied to address this issue. Detection of hydrogen once has been conducted by a traditional hydrogen concentration measuring system with sampling devices and hydrogen sensors that located outside the containment. This arrangement, however, is a compromise between actual requirements for hydrogen measuring device and absence of favorable hydrogen sensors which could be applied in the harsh environment under severe accidents. Most recently, R&D of hydrogen concentration measuring system with in-situ hydrogen sensor has attracted increasing attention. Mitsubishi Heavy Industries, Ltd is focusing their job on an electrochemical hydrogen sensor based on solid state electrolyte. Besides, AREVA has developed a system depending on thermal conductivity detector associated with catalytic combustion sensor which requires external power supply to heat the assembly. In PERIC, we have developed a hydrogen concentration measuring system with in-situ hydrogen sensor which can be set in accident confident area. The hydrogen sensor is originally based on catalytic recombination of hydrogen and oxygen. Generally, catalyst prepared using noble metals such as platinum and palladium is scientifically loaded in the hydrogen sensor to serve as hydrogen sensitive material. On the event of severe accidents, mixture of hydrogen and air can spontaneously diffuse into the hydrogen sensor, where, part of the mixture is involved in a chemical exothermic reaction on the catalyst to generate water and heat. Generally, an increased concentration of hydrogen will raise relatively higher reaction temperature of the hydrogen sensor. The hydrogen concentration related temperature of the hydrogen sensor is detected using steel armored thermocouple. Besides, environmental temperature and pressure in the containment are also acquired to assist calculation. All the data are transferred to a signal processing cabinet, which, performs the calculation and indication functions using programmable logic controller and digital display device, respectively. There is no organic material, mechanical moving and power consumption part in the hydrogen sensor and thermocouple. The system indicated reliable performance in simulated containment under condition of high temperature, pressure, steam, and etc. The hydrogen concentration measuring system illustrated excellent endurance to poisoning species such as iodine and aerosol. Furthermore, the hydrogen sensor also suggested high resistance to irradiation. The system can survive a severe earthquake, and its seismic certification toward to safety shutdown earthquake is class I. Over 80 systems so far have be applied in pressurized water reactor in China and or Pakistan. The latest model is designed according to requirements of CAP1400.

Invasive exotic plant (IEP) species are a significant threat to natural ecosystem integrity and biodiversity, and controlling them is a high priority for the National Park Service. The North-ern Colorado Plateau Network (NCPN) selected the early detection of IEPs as one of 11 monitoring protocols to be implemented as part of its long-term monitoring program. This report represents work completed at Colorado National Monument during 2019. During monitoring conducted June 12–19, a total of 20 IEP species were detected on monitoring routes and transects. Of these, 12 were priority species that accounted for 791 separate IEP patches. IEPs were most prevalent along riparian areas. Yellow sweetclover (Melilotis officinale) and yellow salsify (Tragopogon dubius) were the most commonly detected priority IEPs along monitoring routes, representing 73% of all priority patches. Patches of less than 40 m2 were typical of nearly all priority IEP species except yellow sweetclover. A patch management index (PMI) was created by combining patch size class and percent cover for each patch. In 2019, a large majority of priority IEP patches were assigned a PMI score of low (46%) or very low (50%), indicating small and/or sparse patches where control is generally still feasible. This is similar to the numbers for 2017, when 99% of patches scored low or very low in PMI. Seventy-eight percent of tree patches were classified as seedlings or saplings, which require less effort to control than mature trees. Cheatgrass (Anisantha tectorum) was the most common IEP recorded in transects, found in 30–77% of transects across the different routes. It was the only species found in transects on all monitoring routes. When treated and untreated extra areas near the West Entrance were compared, the treated area had comparable or higher lev-els of IEPs than the untreated area. When segments of monitoring routes conducted between 2003 and 2019 were compared, results were mixed, due to the different species monitored in different time periods. But in general, the number of IEPs per 100 meters is increasing or remaining constant over time. There were notable increases in IEP patches per 100 meters on several routes in 2019: field bindweed (Convolvulus arvensis) along East Glade Park Road; Siberian elm (Ulmus pumila) in Red Canyon; yellow salsify along East Glade Park Road, No Thoroughfare Canyon, No Thoroughfare Trail, and Red Canyon; and yellow sweetclover in No Thoroughfare Canyon and Red Canyon. Network staff will return to re-sample monitoring routes in 2021.

Invasive exotic plant (IEP) species are a significant threat to natural ecosystem integrity and biodiversity, and controlling them is a high priority for the National Park Service. The North-ern Colorado Plateau Network (NCPN) selected the early detection of IEPs as one of 11 monitoring protocols to be implemented as part of its long-term monitoring program. From May 30 to June 1, 2019, network staff conducted surveys for priority IEP species along the Scenic Drive and Cathedral Valley Road monitoring routes at Capitol Reef National Park. We detected 119 patches of six priority IEP species along 34 kilometers of the two monitor-ing routes. There were more patches of IEPs, and a higher percentage of large patches, than in previous years. This indicates that previously identified infestations have expanded and grown. The most common (47.1%) patch size among priority species was 1,000–2,000 m2 (0.25–0.5 acre). The vast majority (93.2%) of priority patches ranked either low (58.8%) or very low (34.4%) on the patch management index scale. Tamarisk (Tamarix sp., 72 patches) was the most prevalent priority IEP species. African mustard (Malcolmia africana, 32 patch-es), field bindweed (Convolvulus arvensis, 9 patches), and Russian olive (Elaeagnus angusti-folia, 3 patches) occurred less commonly. Together, these four species represented 97.5% of all patches recorded in 2019. Four IEP species were found on the monitored routes for the first time: Russian olive (Elaeagnus angustifolia), quackgrass (Elymus repens), Siberian elm (Ulmus pumila), and African mustard (Malcolmia africana, not on the priority species list before 2019). Cathedral Valley Road had higher IEP priority patches per kilometer (5.68) than the Scenic Drive (2.05). IEP species were found on 37.9% (25 of 66) of monitored transects. Almost all these detections were Russian thistle (Salsola sp.). Russian thistle was widespread, present in 33.3% of transects, with an estimated cover of 0.2% across all transects sampled. Across routes monitored in all three rotations (2012, 2015, and 2019), Russian thistle has increased in frequency. However, its frequency remained about the same from 2015 to 2019, and percent cover remains low. Tamarisk and field bindweed have both increased in preva-lence since monitoring began, with tamarisk showing a dramatic increase in the number and size of patches. Immediate control of tamarisk and these other species is recommended to reduce their numbers on these routes. The NCPN plans to Capitol Reef in 2020 to monitor Oak and Pleasant creeks, completing the third rotation of invasive plant monitoring.