Dissertations / Theses on the topic 'Salt diapir'

Marginal zones of salt diapirs and canopies are complex geological environments, with rapid spatial variations in lithology, strain, and fluid-assisted alteration. These complex zones can contain economically attractive hydrocarbon accumulations. However, they are difficult to image seismically due to the irregular geometry of salt bodies and the large property contrast between salt and the surrounding sediments. I present an integrated and multiscale approach to build realistic models of salt margins that represent the geological heterogeneity and seismic anisotropy in such complex zones. Structural field data and petrophysical measurements are used to constrain such models. A suite of evaporite samples of various compositions are used to predict the seismic anisotropy from their crystal preferred orientations (CPOs) and elastic properties. Ultrasonic seismic velocities are measured to calculate the relative contribution of the shape preferred orientations to the seismic anisotropy of such samples. Calculation of the seismic anisotropy produced by thinly interlayered evaporites provides a link between small-scale compositional heterogeneity with large-scale seismic anisotropy. Integration of outcrop structural models, petrophysical measurements and the characterisation of seismic anisotropy of salt is possible through seismic modelling. My results suggest that the seismic anisotropy of these samples is strongly controlled by their CPOs, which ranges from 3 to 7% for halite, from 8 to 10% for anhydrite, and from 13 to 22% for gypsum. Predictions indicate that the contribution of a small amount (< 10 %) of anhydrite can moderately alter the seismic anisotropy of polycrystalline evaporite. A small amount of anhydrite interlayered with halite yields anisotropy parameters with magnitudes of = −0.014, = −0.044, and = −0.193, which agree with those parameters calculated for polycrystalline salt. Such calculations of seismic anisotropy at grain scale enable the study of the propagation of seismic waves through salt margins. Seismic images generated from outcrop models of salt diapir flanks show moderate image degradation if anisotropy of salt is neglected during seismic migration. This methodology provides a foundation for the characterisation of seismic anisotropy of salt with which models of salt margins can be improved.

The Onion Creek Diapir is one of many salt domes proximal to the Uncompahgre thrust front of the ancestral rockies in the Paradox Basin. It is comprised of Paradox Formation evaporites and large blocks of Honaker Trail Formation carbonates that were deformed by loading of Permian Cutler Formation progradational alluvial to fluvial fans. The history of salt movement in the Onion Creek Diapir is recorded in the near-salt strata. Large salt bodies and their adjacent mini-basins evolve conforming to a complex relationship between salt withdrawal, creating localized accommodation, and sediment deposition. Migrating mini-basin depo-centers, thinned and folded strata, and spatial facies trends reveal the relative rates of diapirism and sedimentation. The study area outcrop, north of the diapir, is divided by significant stratigraphic horizons that help define depositional periods. Six measured sections in the study area reveal higher preservation rates of fine grained floodplain deposits, typically destroyed in alluvial environments, than at locations correlating to stratigraphic levels high in the outcrop suggesting a low accommodation environment evolving into higher accommodation where stacked channel complexes are preserved. Preserved slump folding at the base of the outcrop reveals that although some salt emergence occurred in the earliest depositional period it was not significant enough to preclude sediment deposition or to divert the Cutler fluvial network and destroy floodplain facies. A 3-D digital outcrop, modeled from photogrammetric data, illustrates the development of localized accommodation, attracting fluvial channel in a near-salt, tight axial syncline during the later depositional period. These evidences suggest a greater emergence of the diapir and likely diversion of the Cutler channel complexes.

This thesis uses results of systematic numerical models to argue that externally inactive salt structures, which are potential targets for radioactive waste disposal, might be internally active due to the presence of dense layers or blocks within a salt layer.

The three papers that support this thesis use the Gorleben salt diapir (NW Germany), which was targeted as a future final repository for high-grade radioactive waste, as a general guideline.

The first two papers present systematic studies of the parameters that control the development of a salt diapir and how it entrains a dense anhydrite layer. Results from these numerical models show that the entrainment of a dense anhydrite layer within a salt diapir depends on four parameters: sedimentation rate, viscosity of salt, perturbation width and the stratigraphic location of the dense layer. The combined effect of these four parameters, which has a direct impact on the rate of salt supply (volume/area of the salt that is supplied to the diapir with time), shape a diapir and the mode of entrainment. Salt diapirs down-built with sedimentary units of high viscosity can potentially grow with an embedded anhydrite layer and deplete their source layer (salt supply ceases). However, when salt supply decreases dramatically or ceases entirely, the entrained anhydrite layer/segments start to sink within the diapir. In inactive diapirs, sinking of the entrained anhydrite layer is inevitable and strongly depends on the rheology of the salt, which is in direct contact with the anhydrite layer. During the post-depositional stage, if the effective viscosity of salt falls below the threshold value of around 10¹⁸-10¹⁹ Pa s, the mobility of anhydrite blocks might influence any repository within the diapir. However, the internal deformation of the salt diapir by the descending blocks decreases with increase in effective viscosity of salt.

The results presented in this thesis suggest that it is highly likely that salt structures where dense and viscous layer/blocks are present undergo an internal deformation processes when these dense blocks start sinking within the diapir. Depending on size and orientation of these blocks, deformation pattern is significantly different within the diapir. Furthermore, model results applied to the Gorleben diapir show that the rate of descent of the entrained anhydrite blocks differs on different sides of the diapir. This suggests that if the anhydrite blocks descent within the Gorleben diapir, they initiate an asymmetric internal flow within it.

Un des objectifs de la restauration structurale, sujet de cette thèse, est de mettre en évidence les défauts d'interprétation ou les zones potentiellement fracturées. L'extension de cette technique en volume nécessite la définition a priori des propriétés des matériaux utilisés, notamment lorsque ces propriétés sont définies à une échelle fine. Une première partie, ce travail propose une méthode de mise à l'échelle des propriétés mécaniques utilisées pour les calculs de restauration en volume. La principale hypothèse repose sur la loi de comportement utilisée pour les matériaux définis à l'échelle grossière, supposés isotropiques transverses élastiques. Le calcul des propriétés équivalentes se fait par identification, après simulation par Éléments Finis. Cette technique a l'avantage d'assurer la conservation de l'énergie pour le même type de chargement. Dans une dernière partie, ce travail traite la gestion de la tectonique salifère lors de la restauration structurale. Les diapirs de sel présentent des topologies, des rhéologies, et des séquences de dépôt très caractéristiques. Ce mémoire présente une méthodologie de restauration multi-cartes, dont la prise en compte des relations inter-horizons est respectée dans les séquences halocinétiques. Une application de cette méthode est présentée sur le bassin de La Popa (Mexique) où les différentes interprétations réalisées au travers de leurs restaurations sont comparées

This thesis focuses on calculation of finite and progressive deformation in different tectonic scales using 2D numerical models with application to natural cases. Essentially, two major tectonic areas have been covered: a) salt tectonics and b) upper mantle deformation due to interaction between the lithosphere and asthenosphere. The focus in salt tectonics lies on deformation within down-built diapirs consisting of a source layer feeding a vertical stem. Three deformation regimes have been identified within the salt: (I) a squeezing channel flow underneath the overburden, (II) a corner flow underneath the stem, and (III) a pure channel flow within the stem. The results of the model show that the deformation pattern within the stem of a diapir (e.g. symmetric or asymmetric) can reveal information on different rates of salt supplies from the source layer (e.g. observed in Klodowa-diapir, Poland). Composite rock salt rheology results in strong localization and amplification of the strain along the salt layer boundaries in comparison to Newtonian rock salt. Flow and fold structures of passive marker lines are directly correlated to natural folds within a salt diapir. In case of the upper mantle, focus lies on deformation and resulting lattice preferred orientation (LPO) underneath an oceanic plate. Sensitivity of deformation and seismic anisotropy on rheology, grain size (d), temperature (T), and kinematics (v) has been investigated. The results of the model show that the mechanical lithosphere-asthenosphere boundary is strongly controlled by T and less so by v or d. A higher strain concentration within the asthenosphere (e.g. for smaller potential mantle temperatures, higher plate velocities, or smaller d) indicates a weaker coupling between the plate and the underlying mantle, which becomes stronger with the age of the plate. A Poiseuille flow within the asthenosphere, significantly affects the deformation and LPO in the upper mantle. The results of the model show, that deformation in the upper mantle at a certain distance away from the ridge depends on the absolute velocity in the asthenosphere. However, only in cases of a driving upper mantle base does the seismic anisotropy and delay times reach values within the range of natural data.

Salt diapirs are some of the most dynamic geological structures in sedimentary basins and vertical rise through their overburdens leads to the development of complex fault systems. Polygonal fault systems constitute a major structural element of fine-grained sediments in sedimentary basins, forming without the requirement of tectonic extension during the early burial phase of sediment compaction and dewatering. These same fine-grained sedimentary overburdens are also deformed by salt diapirs and their associated fault systems in basins such as the Gulf of Mexico, the South Atlantic margins and the North Sea. The aim of this research was to investigate the interactions between salt diapirism and faulting in overburdens deformed by polygonal fault systems using 3D seismic data sets from the Central North Sea and the extensional domain of the Espírito Santo Basin on the SE continental margin of Brazil. In both case studies the regional isotropic planform arrangements of polygonal faults mapped in the post-salt overburden have preferred (radial) orientations around salt stocks, orthogonal alignments with tectonic faults and salt walls, and concentric arrangements in withdrawal basins. Radial faults around salt stocks are invariably layer-bound, conforming to the same discrete layer of stratigraphy as laterally equivalent to layer-bound polygonal fault systems. In the Espírito Santo Basin, the lateral distribution and stacking of polygonal faults is heavily influenced by the distribution of proximal and distal seismic facies. In the Central North Sea spacing, throw and fault length vary as a function of tier thickness. Polygonal and radial faults in the same tier have a similar range of maximum throws and spacing but differ in length and aspect ratios. Radial faults are classified as perturbed members of the basin-wide polygonal fault system which propagate primarily under the influence of compaction and contraction but in an anisotropic stress field. Stacked arrays of layer-bound radial and polygonal faults formed sequentially where upper tier boundaries date the cessation of fault activity. The radial fault zone is between 2-4 stock radii wide. The radial fault zone expanded as salt growth intensified or widened, and contracted as they slowed or became narrower. However, the width of the radial fault zone is not related to the hinge in the domed overburden discrediting arching as mechanism forming the radial faults. Instead, the transition boundary separating zones of radial and polygonal faults in a tier is interpreted to reflect the lateral-extent of hoop stress around salt stocks during faulting. An upward change in the regional polygonal planform and dip polarity of polygonal faults in the Espírito Santo Basin is attributed to a change in the regional stress field during the cessation of thin-skinned extension and gravity gliding and the onset of inversion. The results of this thesis highlight the sensitivity of polygonal fault system to local stress anisotropy and provide a potential route for reconstructing the palaeostate of stress around salt diapirs.

The eastern Willouran Ranges and northern Flinders Ranges, South Australia contain Neoproterozoic and Cambrian outcrop exposures of diapiric breccia contained in salt diapirs, salt sheets and associated growth strata that provide a natural laboratory for testing and refining models of salt-sediment interaction, specifically allochthonous salt initiation and emplacement and halokinetic deformation. Allochthonous salt, which is defined as a sheet-like diapir of mobile evaporite emplaced at younger stratigraphic levels above the autochthonous source, is emplaced due to the interplay between the rate of salt supply to the front of the sheet and the sediment-accumulation rate, and may be flanked by low- to high-angle stratal truncations to halokinetic folds. Halokinetic sequences (HS) are localized (<1000 m) unconformity-bound successions of growth strata adjacent to salt diapirs that form as drape folds due to the interplay between salt rise rate (R) and sediment accumulation rate (A). HS stack to form tabular and tapered composite halokinetic sequences (CHS), which have narrow and broad zones of thinning, respectively. The concepts of CHS formation are derived from outcrops in shallow water to subaerial depositional environments in La Popa Basin, Mexico and the Flinders Ranges, South Australia. Current models for allochthonous salt emplacement, including surficial glacial flow, advance above subsalt shear zones and emplacement along tip thrusts, do not address how salt transitions from steep feeders to low-angle sheets and the model for the formation of halokinetic sequences has yet to be fully applied or tested in a deepwater setting. Thus, this study integrates field data from South Australia with subsurface data from the northern Gulf of Mexico to test the following: (1) current models of allochthonous salt advance and subsalt deformation using structural analysis of stratal truncations adjacent to outcropping salt bodies, with a focus on the transition from steep diapirs to shallow salt sheets in South Australia; and (2) the outcrop-based halokinetic sequence model using seismic and well data from the Auger diapir, located in the deepwater northern Gulf of Mexico. Structural analysis of strata flanking steep diapirs and allochthonous salt in South Australia reveals the transition from steep diapirs to shallowly-dipping salt sheets to be abrupt and involves piston-like breakthrough of roof strata, freeing up salt to flow laterally. Two models explain this transition: 1) salt-top breakout, where salt rise occurs inboard of the salt flank, thereby preserving part of the roof beneath the sheet; and 2) salt-edge breakout, where rise occurs at the edge of the diapir with no roof preservation. Shear zones, fractured or mixed `rubble zones' and thrust imbricates are absent in strata beneath allochthonous salt and adjacent to steep diapirs. Rather, halokinetic drape folds, truncated roof strata and low- and high-angle bedding intersections are among the variety of stratal truncations adjacent to salt bodies in South Australia. Interpretation and analysis of subsurface data around the Auger diapir reveals similar CHS geometries, stacking patterns and ratios of salt rise and sediment accumulation rates, all of which generally corroborate the halokinetic sequence model. The results of this study have important implications for salt-sediment interaction, but are also critical to understanding and predicting combined structural-stratigraphic trap geometry, reservoir prediction and hydrocarbon containment in diapir-flank settings.

The modes in which faults can propagate and grow through subsurface rocks and strata are key to the establishment of fluid paths in sedimentary basins; faults are potential conduits for fluid in some regions, at the same time they are associated with fault-related traps in others. The classical fault propagation models addressed in the published literature have so-far considered isolated, linkage (lateral-tip linkage and dip-linkage), constant-length, and coherent models. However, the propagation histories of faults in regions dominated by salt tectonics are scarcely documented; rather, the existing fault propagation models lack critical thinking when applied to crestal faults, particularly due to the limited resolution of imaged strata in most publications, and the relatively small size of crestal faults (length < 2.3 km, maximum throw < 50 m). With the increasing use of high-resolution seismic data in recent decades, it is now possible to undertake research into the evolution of both crestal faults and fluid flow paths in regions dominated by salt tectonics. In parallel, the uniqueness of crestal faults in terms of their scales has brought up important questions about how data resolution and scale variance influence many a fault analysis, and the current fault propagation models, when based on seismic and outcrop information. This research uses high resolution seismic data from the Espírito Santo Basin, offshore SE Brazil, to investigate the growth histories of crestal faults, fluid flow in an area of significant salt tectonics, and how crestal faults are associated with traps in supra- salt successions. To answer the question, in a second stage, of how scale variance can influence the analysis of faults’ propagation histories, data from Somerset (Bristol Channel) and the Ierapetra Basin (Crete) were collected in the field to broaden the database in this thesis from the larger, rift-basin scale to the seismic and sub-seismic scales. Segment linkage is predominant in areas where crestal faults grow. Interpreted crestal faults in SE Brazil propagated vertically and horizontally. Horizontal propagation was often hindered by natural barriers such as an accommodation zone (Chapter 4), or oblique transfer zones (Chapter 5), onto which faults terminate. Vertical propagation stopped when the fault meets the sea floor or when vertical propagation was accommodated by blind faults or larger (adjacent) faults showing relatively large displacements. Hence, this thesis shows that the propagation of crestal faults does not follow a ‘coherent growth model’. Rather, the geometry and history of propagation of discrete faults segments are not comparable. In SE Brazil, large fault segments propagated to link with non-reactivated small fault segments on the crest of the salt ridge, and can show later ‘blind’ propagation towards the surface. In terms of how scale variance can potentially (negatively) influence fault growth models interpreted on seismic data and in the field, a new quantitative method and two new parameters (sampling interval and module error) are introduced in this thesis for faults of multiple scales - from a few meters to 10s of kilometers. Sampling interval has a significant influence on the interpretation of fault growth histories. By changing one’s sampling interval: 1) the interpretation of fault geometries is significantly changed; 2) maximum fault throw values are underestimated; 3) fault segments are underrepresented; 4) the geometry of fault linkage zones is changed; 5) the width of fault linkage zones is underestimated; 6) fault interaction zones are lost. Using the SE Brazil seismic data, the accuracy of Throw-Distance plots was shown to be quantitatively lost when sampling intervals were larger than 37.5 m (every 3 shot-points) for the ‘unique’ crestal fault families in this thesis. However, this thesis demonstrates that sampling intervals adopted by interpreters should differ depending on the resolution of seismic data used, and the total length of investigated structures. A practical sampling interval/fault length ratio is therefore proposed in this work to address the caveats behind using variable (and indiscriminate) sampling intervals when analysing faults. Supra-salt sequences capable of promoting episodic fluid flow in regions of salt tectonics are of vital economic importance. Following on the two latter themes (crestal faulting and fault scaling), the thesis addressed the episodic fluid flow documented in the Espírito Santo Basin in a third stage. The results of this section are proposed as a case study for supra-salt sequences. In detail, seal failure is systematically recorded in the study area, and is interpreted to have contributed to most of the supra-salt fluid flow events investigated in SE Brazil. Six types of traps are therefore widely identified in supra-salt successions of the Espírito Santo Basin – all forming examples of trapping geometries in sedimentary basins associated with salt tectonics. Regardless of a thermogenic or diagenetic origin for fluid off Espírito Santo, the results in this thesis demonstrate important (and focused) fluid flow above salt giants when, at least, two critical conditions are observed: 1) a certain thickness of overburden strata is deposited on top of the salt structures, 2) the generation of highly developed (i.e. large) crestal fault systems is observed over these same salt structures. It is therefore postulated that, if overburden strata is thinner than a certain value, or pressure imposed by growing salt increases significantly, active salt intrusion occurring together with fluid flow will replace more focused fluid flow features in salt giants.

En aquesta tesi en primer lloc s’ha dut a terme el desenvolupament d’una aplicació de diari miccional per a smart-phon (eDM3d), seguint l’estructura del diari miccional de tres dies validat en espanyol i amb un disseny intuïtiu per facilitar el compliment per part dels pacients. Els resultats del diari miccional electrònic són transmesos de forma automàtica a un servidor web que és capaç de calcular els valors mitjans i màxims del diari miccional. D’aquest diari miccional electrònic se n’ha valorat la factibilitat en primer lloc en un grup reduït de pacients. Posteriorment s’ha demostrat la factibilitat, fiabilitat, bona correlació amb el diari miccional en paper i validesa convergent d’aquesta aplicació electrònica de diari miccional en un grup de pacients amb síndrome de bufeta hiperactiva o nictúria que disposaven de smart-phone. La majoria dels pacients han manifestat que elegirien el diari miccional electrònic eDM3d front al diari miccional convencional en paper si haguessin de repetir un diari miccional.
In a first phase a 3 day bladder diary as an easy-to-use application for smart-phone (eDM3d) was developed following the structure of the Spanish validated 3 day bladder diary. The preliminary feasibility of the app was assessed in a reduced number of patients. In a second phase, the feasibility, reliability, correlation with paper bladder diary and convergent validity of the app was proved in a group of patients with nocturia or overactive bladder syndrome and who possessed a smart-phone. Most of patients referred they would choose the electronic bladder diary eDM3d if they had to repeat a bladder diary again.

Objetivo: Probar la utilidad de la dosis única semanal de hierro en el tratamiento y prevención de la anemia ferropénica en mujeres adolescentes.
Metodología: Se realizó un ensayo clínico aleatorizado en paralelo, en mujeres adolescentes de 15 telesecundarias del Estado de Morelos, México. Se formaron 3 grupos de estudio en cada telesecundaria, 2 recibieron esquemas diferentes de suplementación con hierro: 1) dosis diaria; 2) dosis semanal; el tercero, de no anémicas; no recibió suplementación y fue el control. Se tomaron muestras iniciales y finales de sangre venosa a las adolescentes, a fin de determinar los valores de hemoglobina, hematocrito y colesterol. Se suplementó durante 16 semanas. Se investigaron parasitosis en heces para ajustar por éstas como un posible confusor. Se midió peso, talla, circunferencia de cintura y cadera. Adicionalmente se aplicó un formulario que contempló: aspectos dietéticos (mediante encuesta de recordatorio de 24 horas); aspectos socioeconómicos; y preguntas respecto a las características clínicas y psicológicas de la menstruación, así como de la actividad física que realizan las adolescentes.
Resultados: Participaron en el estudio 511 alumnas de educación secundaria. El 31% realizan 3 tiempos de comida y el 56% 4 y más; el 59% de las mujeres refirieron haber aumentado la cantidad de su alimentación respecto a cuando iban a la primaria. El 62% no lleva nada de comer de su casa a la escuela y el 95% compran alimentos en la escuela. El 85% de las adolescentes tiene antecedentes hereditarios de obesidad. Los valores promedio basales de las mujeres fueron: peso, 46kg (DE 8.8); talla, 151cm (DE 5.5); hemoglobina, 12.5g/dl (DE 0.6); hematocrito, 41% (DE 2.9). Los valores de hemoglobina en el grupo de suplementación diaria pasaron de 12.2 (DE 0.7) a 13.2g/dl (DE 1.0); en el grupo de suplementación semanal, se encontraron valores muy similares, de 12.2 (DE 0.7) a 13.1g/dl (DE 1.0) y en el grupo control pasó de 13.3 (DE 0.4) a 13.6g/dl (DE 1.2). En los tres grupos las diferencias fueron estadísticamente significativas (p<0.05)
Conclusiones: Las características de la muestra estudiada, son adecuadas para extrapolar los resultados a poblaciones similares. Después de las 16 semanas de suplementación hubo un comportamiento similar en los dos grupos suplementados, lo que lleva a concluir que la dosis única semanal es tan efectiva como la dosis diaria de hierro en la prevención y corrección de la deficiencia de hierro en las mujeres adolescentes. Se avanzó en el conocimiento de la prevención de la deficiencia de hierro y de la anemia ferropriva de mujeres adolescentes, mediante la utilización de dosis única semanal que reduce costos, aumenta el apego al tratamiento y mejora la absorción de hierro.
Objective: To test the utility of a single, weekly dose of iron in the treatment and prevention of anemia caused by iron deficiency in adolescent girls.
Methodology: A randomized parallel clinical study was carried out with adolescent girls from 15 secondary schools in the state of Morelos, Mexico. Three study groups were formed in each secondary school: Two received different iron supplementation schemes: 1) a daily dose 2) a weekly dose; the third, the non-anememic group, did not receive any supplementation and was the control group. Initial and final samples of antecubital vein (venous blood) were taken, in order to establish the hemoglobin, hematocrit and cholesterol levels. The supplements were administered during a period of 16 weeks. Faeces were checked for parasitosis in order to make adjustments for same as possible confounding variables. Weight, height, waist and hip measurements were taken. Additionally, a survey was carried out which contemplated the following: dietary aspects (via a 24- hour dietary recall) socioeconomic aspects and questions relating to the clinical and psychological characteristics of menstruation, as well as the physical activity carried out by the adolescent girls.
Results: 511 female secondary school students participated in the study. 31% were given 3 meals and 56% four and more; 59% of the girls claimed to have increased their daily intake of food in comparison to what they ate at primary school. 62% do not take any food to school from their home and 95% buy food at the school. 85% of the girls have a hereditary predisposition to obesity. The average basal levels of the girls were: weight, 46kg (SD 8.8); height, 151cm (SD 5.5); hemoglobin, 12.5g/dl (SD 0.6); hematocrit, 41% (SD 2.9). The hemoglobin levels in the daily supplementation group rose from 12.2 (SD 0.7) to 13.2g/dl (SD 1.0); in the weekly supplementation group very similar levels were found, from 12.2 (0.7) to 13.1g/dl (SD 1.0) and in the control group there was a rise of 13.3 (SD 0.4) to 13.6g/dl (DE 1.2). In the three groups, the differences were statistically significant (P<0.5).
Conclusions: The characteristics of the sample make it possible for the results to be extrapolated to similar sectors of the population in other communities. After 16 weeks of supplementation, there was a similar type of behaviour in the two supplementation groups, which leads to the conclusion that the single weekly dose is as effective as the daily iron dose in the prevention and correction of iron deficiency in adolescent girls. Progress was made on knowing how to prevent iron deficiency and anemia caused by iron deficiency in adolescent girls, through the use of a single weekly dose which reduces costs, increases compliance to treatment and improves the absorption of iron.

El rápido incremento de la resistencia antibiótica, junto con la falta de nuevos antibióticos en desarrollo, representa un problema médico de primera magnitud. En este escenario, las polimixinas en general y la colistina en particular en nuestro medio, constituyen en muchas ocasiones la última opción terapéutica. Las polimixinas hicieron su aparición en la práctica clínica en los años 50. Sin embargo, pronto fueron relegadas a un segundo plano en favor de los “menos tóxicos” aminoglucósidos y otros antipseudomónicos no nefrotóxicos. Este hecho provocó que tanto su desarrollo pre-clínico como su posterior proceso regulador no se realizaran de acuerdo a los estándares actuales. Como consecuencia de esto, y a pesar de los muchos avances realizados en los últimos años en el campo de la farmacología preclínica y clínica de las polimixinas, la información disponible en el momento actual resulta insuficiente para dar recomendaciones firmes que guíen su uso en la práctica clínica diaria. Los objetivos del presente trabajo fueron: 1. Valorar mediante un trabajo prospectivo observacional, la posible relación entre los niveles plasmáticos de colistina y el desarrollo de nefrotoxicidad durante el tratamiento. 2. Valorar en una cohorte de pacientes con infecciones causadas por Pseudomonas aeruginosa extremadamente resistente, la posible relación entre los niveles plasmáticos de colistina y la curación clínica y la mortalidad cruda a día 30. 3. Valorar mediante un estudio multicéntrico, aleatorizado no enmascarado, el posible impacto de una monitorización terapéutica de colistina en la práctica clínica diaria. Las conclusiones del presente trabajo fueron: 1. La colistina es un fármaco con un estrecho margen terapéutico siendo la nefrotoxicidad el efecto secundario limitante más frecuente. 2. Los niveles plasmáticos de colistina se relacionan de forma independiente con la aparición de nefrotoxicidad durante el tratamiento. Los valores que mejor predicen la aparición de nefrotoxicidad a día 7 de tratamiento y al final del mismo fueron 3,33 mg/L y 2, 42 mg/L respectivamente. 3. Con las dosis utilizadas en la práctica clínica habitual, incluyendo aquellos regímenes que utilizan dosis máximas (9 millones de UI/día), y en pacientes sin insuficiencia renal, es difícil alcanzar concentraciones plasmáticas de colistina en la fase de equilibrio estacionario consideradas óptimas (2,5 mg/L). 4. Los niveles plasmáticos de colistina no se asociaron con la curación clínica ni con la mortalidad cruda a día 30 de los pacientes con infecciones por Pseudomonas aeruginosa extremadamente resistente. 5. La monitorización terapéutica de la colistina no tuvo impacto sobre la curación ni la mortalidad cruda a día 30. 6. La monitorización de los niveles plasmáticos de colistina podría ser útil en la prevención de la nefrotoxicidad durante el tratamiento de colistina.
In an era of increasing rates of multidrug resistance and a dry drug-development pipeline for new antimicrobial agents, the polymyxin antibiotics—colistin and polymyxin B—have had a substantial resurgence in their use for treatment of infections caused by Gram-negative bacteria. Polymyxins became clinically available in the 1950s, however, they soon fell out of favour in favor of “less toxic” aminoglycosides and other antipseudomonic drugs. For this reason, the polymyxins were not subjected to the drug development procedures and regulatory scrutiny needed for modern drugs. Despite substantial progress has been made in the study of preclinical and clinical pharmacology of polymyxins, information to guide their clinical use is scarce. In this scenario, the aims of this study were: 1. To determine in a cohort of patients treated with colistin, the incidence and the potential risk factors of colistin-associated nephrotoxicity including colistin plasma levels. 2. To assess the risk factors of 30-day all cause mortality including colistin plasma levels, in a cohort of patients infected by colistin-susceptible extremely drug-resistant (XDR) P. aeruginosa. 3. To assess the impact of colistin therapeutic drug monitoring (TDM) in daily clinical practice. A prospective, non-blinded multicenter study was designed to compare clinical outcomes in patients randomized to standard dosing vs. TDM (dose adjusted based on levels and renal function). The conclusions of the study were: 1. Colistin has a narrow therapeutic window being colistin-induced nephrotoxicity the major dose-limiting adverse effect. 2. Colistin plasma levels are predictive of acute kidney injury (AKI) during treatment. The breakpoints that better predicted AKI were 3.33 mg/L (P < 0.001) on day 7 and 2.42 mg/L (P < 0.001) at the end of treatment. 3. If we accept the target of colistin concentration is 2.5 mg/L, it becomes apparent that this is likely to be unachievable in certain patient populations, specifically in patients with a good renal function. 4. In XDR P. aeruginosa infections, colistin plasma levels were not related to 30-day all case mortality or clinical outcome. 5. Colistin TDM was not related to clinical cure or mortality. 6. In view of the narrow therapeutic window of polymyxins and the relationship between colistin plasma levels and the development of nephrotoxicity, there is a strong rationale for TDM in order to maximize clinical benefits while diminish adverse effects. However, the benefit of this approach should be evaluated in new appropriate prospective research studies.

Objetivo Los objetivos de esta tesis fueron: (I) investigar la aplicación de un tratamiento de rehabilitación cognitiva computerizada domiciliaria en pacientes de ictus con déficit cognitivo en fase crónica (II) investigar la influencia de la ejecución de actividades cognitivamente estimulantes en el rendimiento cognitivo de los pacientes en fase crónica. Método Se realizó un estudio de dos brazos, cruzado, doble ciego y aleatorizado. Treinta pacientes de ictus en fase crónica, entre 24 y 62 años. Los participantes reclutados era antiguos pacientes de Institut Guttmann, que habían realizado tratamiento intensivo en la fase post- aguda, y que desde el alta (t0) hasta el reclutamiento no habían mostrado cambios significativos a nivel cognitivo. En la fase I, el Grupo A recibió un tratamiento personalizado de telerehabilitación cognitiva (CCT-C) y el Grupo B realizó un tratamiento sham, una plataforma de ejercicios no personalizada (CCT-non-C) durante 6 semanas. Después de un periodo de descanso de 3 meses, cada grupo recibió el otro tratamiento (fase II). Los participantes fueron evaluados en el reclutamiento (20 meses después del alta, t1), después de la fase I (t2), después del descanso (t3), después de la fase II (t4), y en un seguimiento 6 meses después (t5). Las evaluaciones incluyeron test, y escalas funcionales para paciente y familiar y una escala de reserva cognitiva para evaluar la frecuencia de actividades cognitivamente estimulantes (CRS). Resultados Ambos grupos mostraron mejoras significativas después de los tratamientos (periodo t1 – t5). Después de la fase I, las comparaciones intergrupales revelaron que el Grupo A mostró un descenso significativo en quejas subjetivas (RSAB: p = 0.02, d = 0.8) y que el Grupo B mostró mejora en la puntuación de algunas pruebas. Después de ambos tratamientos (t4), continuó observándose un descenso en las quejas subjetivas del Grupo A (PRMQ: p = 0.03, d = 0.9; PCRS: p = 0.04, d = 0.4; BRIEF -A: p = 0.04, d = 0.6). Ambos grupos mostraron mejoras en pruebas de rendimiento óptimo (Grupo A en Clave de Números: p=0.01, d=1; Grupo B en RAVLT Reconocimiento p=0.02, d=0.6). En cuanto a la frecuencia de hábitos y rutinas, la CRS mostró diferencias significativas en la frecuencia de actividades cognitivamente estimulantes antes (CRS-Pre-stroke) y después del ictus (CRS-Post-stroke). Los subíndices de la CRS- Post stroke mostraron correlación positiva con las escalas funcionales (RSAB, BRIEF-A y PCRS). Conclusiones Los pacientes crónicos con déficits cognitivos derivados de un ictus se pueden beneficiar de un tratamiento de telerehabilitación cognitiva domiciliaria. Recibir un tratamiento basado en CCT-C y la frecuencia de actividades cognitivamente estimulantes, están relacionadas con un descenso de las quejas subjetivas.
Objective The objectives of this thesis were: (I) to investigate the application of a home computerized cognitive rehabilitation treatment in stroke patients with chronic pase cognitive deficits (II) to investigate the influence of the execution of cognitively stimulating activities on the cognitive performance of patients in chronic phase. Method A study of two arms, crossed, double blind and randomized, was carried out.Thirty stroke patients in chronic phase, between 24 and 62 years. The recruited participants were former patients of Institut Guttmann, who had undergone intensive treatment in the post-acute phase, and who since discharge (t0) to recruitment had not shown significant changes at the cognitive level. In phase I, Group A received a personalized cognitive telerehabilitation treatment (CCT-C) and Group B performed a sham treatment, a non-personalized exercise platform (CCT-non-C) for 6 weeks. After a 3-month washout period, each group received the other treatment (phase II). Participants were evaluated in recruitment (20 months after discharge, t1), after phase I (t2), after washout (t3), after phase II (t4), and at follow-up 6 months later (t5). The evaluations included tests, and functional scales for patient and family as well as a cognitive reserve scale to assess the frequency of cognitively stimulating activities (CRS). Results Both groups showed significant improvements after treatments (t1 - t5 period). After phase I, intergroup analyzes revealed that Group A showed a significant decrease in subjective complaints (RSAB: p = 0.02, d = 0.8). On the other hand, Group B showed improvement in some tests. After both treatments (t4), a decrease in the subjective complaints of Group A continued (PRMQ: p = 0.03, d = 0.9; PCRS: p = 0.04, d = 0.4; BRIEF -A: p = 0.04, d = 0.6). Both groups showed improvements in the tests (Group A in Symbol Digit: p = 0.01, d = 1; Group B in RAVLT Recognition p = 0.02, d = 0.6). The CRS showed significant differences in the frequency of cognitively stimulating activities before (CRS-Pre-stroke) and after stroke (CRS-Post-stroke). The sub indexes of the CRSPost-stroke showed a positive correlation with the functional scales (RSAB, BRIEF-A and PCRS). Conclusions Chronic stroke patients with cognitive deficits can benefit from a home based cognitive telerehabilitation treatment. Receiving a CCT-C treatment and the frequency of cognitively stimulating activities have positive correlation with a decrease in subjective complaints.

There is a new trend in organizational psychology to address the transient nature of constructs through intra-individual studies. This approach is mostly used to understand phenomena which are highly sensitive to changes in the environment and to internal states in workers, such as the intra-individual variation in well-being related concepts such as cognition, affect and motivational states. Traditionally the concept of work engagement has been considered and studied as a relatively stable-in-time concept, a great portion of research has been carried out with transactional designs and with self-report questionnaires. However, this methodology does not allow capturing the variability and fluctuations of the state and intra-individual transient cognitive and affective states of work engagement. Therefore, this dissertation aims to address the study of the intra-individual variables of cognition and affect that could be related to the daily state work engagement and explain how they are related. In order to capture the fluctuations of the cognitive, affective and motivational states, in this thesis diary experiences of 117 workers on 1170 work events were collected and analyzed with a longitudinal methodology and the diary technique. As a result, this dissertation proposes theoretical framework and reports three empirical studies to understand how the internal variables of the individual are related in a dynamic and transient process and which variables foster or inhibit work engagement. Upon the basis of the empirical studies, a model is proposed to explain how the antecedents of state work engagement function and which are some moderators of transient affect. The results highlight the importance of the temporary character of states such as affect, daily work engagement and cognitive appraisals about events at work. It proposes a multilevel approach to study the dynamics of the process that generates work engagement on a daily basis. To conclude, in the final chapter, practical managerial implication and future avenues of research are discussed.
El enfoque de abordar la naturaleza transitoria de algunos constructos de la psicología de las organizaciones a través del estudio intra-individual es novedoso y es la tendencia que existe actualmente para comprender fenómenos altamente sensitivos a los cambios del entorno y de la vida interna del trabajador, como son la cognición, el afecto y los estados motivacionales. Mayormente se ha estudiado el concepto del work engagement como un concepto estable en el tiempo y la mayor parte de la investigación se ha realizado con diseños transeccionales y con cuestionarios de auto-reporte, metodologías que no permiten captar la variabilidad y fluctuaciones del estado. En este contexto cobra relevancia el estudio intra-individual de la vida interna y estados transitorios de los trabajadores. La presente tesis tiene como objetivo abordar al estudio intra-individual de variables transitorias cognitivas y afectivas que pueden estar relacionadas con el work engagement diario y explicar cómo se relacionan. Con la intención de captar las fluctuaciones de los estados cognitivos, afectivos y motivacionales de los trabajadores se recogió y analizó experiencias diarias de 117 trabajadores del sector servicios, se usó una metodología longitudinal y con la técnica de diario (N = 1170 registros en el lugar de trabajo). En el presente trabajo se propone un marco teórico y se realizan tres estudios empíricos para entender cómo se relacionan las variables internas del individuo en un proceso dinámico y transitorio, y qué variables facilitan o inhiben el work engagement. A partir de los estudios empíricos se propone un modelo que explica cómo funcionan los antecedentes del state work engagement y moderadores del afecto transitorio. Los resultados de estos tres estudios destacan la importancia de la consideración temporal de estados como el afecto, el work engagement diario y las valoraciones cognitivas sobre los eventos en el trabajo y proponen un enfoque multinivel para estudiar la dinámica del proceso de generación del work engagement diario. Para finalizar se discuten las implicaciones prácticas y direcciones futuras de investigación en esta área de estudio.

Les modèles analogiques de formation des bassins en pull-apart considèrent l’existence de discontinuités basales qui transmettent le mouvement de décrochement dans la couverture sus-jacente. Nous présentons ici une série de modèles réalisés selon un mode opératoire innovant, qui permet la formation de ce type de bassins au-dessus d'une couche visqueuse, par le seul effet de coulissements latéraux dans la couverture, indépendamment du socle. Ce travail est inspiré d’un exemple naturel, le bassin d'El Hamma-Gabes, en Tunisie centrale. Ce bassin correspond à une zone de relais extensif entre deux Couloirs de Décrochements Principaux (CCP) de direction N100-110. Ces couloirs font partie de l’expression en surface de la zone de cisaillement crustale dite « Accident Sud Tunisien ». Ils sont marqués par des cinématiques transtensives dextres pendant l’extension N80 du Crétacé supérieur, et transpressives dextres pendant les compressions N140 au cours du Néogène. Ces mouvements ont assuré et maintenu l’extension de la zone de relais au cours des événements tectoniques aussi bien extensifs que compressifs. Dans cette zone de relais la couverture sédimentaire est adhérente au substratum anté-triasique dans sa partie méridionale, en l’absence du trias supérieur évaporitique. La structuration en subsurface montre un dispositif en horst et graben qui se branchent aux (CCP). Deux méga-grabens sont identifiés : celui d’El Hamma à l’Ouest et celui de Chenchou à l’Est, séparés par le Horst de Jebel Hallouga. Chacun de ces grabens est structuré à son échelle, en une succession de horsts et graben de second ordre. En sections sismiques, des structures en « sabliers » formées par l’interconnexion dans les couches du Crétacé supérieur, de grabens séparés dans des niveaux sous-jacents, se développent dans la partie septentrionale de la zone de relais. Ces structures témoignent d’une extension plus prononcée que dans la partie méridionale, favorisée par un découplage couverture/socle lié à une présence d’évaporites Triasiques dans cette partie de la zone de relais. Les modèles analogiques montrent que : 1- Dans le cas d’une couverture reposant sur une couche visqueuse (silicone) également répartie dans la zone de relais, le pull-apart initié comporte deux grabens chacun connecté à l’extrémité de l’un des (CCP). Les failles bordières de ces structures montrent des tracés courbes. Leur orientation est celle de failles de type R au niveau de leurs jonctions au (CCP), et évolue vers celle de R’, en s’en éloignant. Des percements « diapiriques » se produisent le long des axes des grabens. La restauration des étapes de déformation permet de distinguer les trois stades de mise en place de ces diapirs : stade réactif associé à l’ouverture du graben, actif puis passif syn-cinématiques. Un effondrement du toit de diapir se produit à un stade avancé de la déformation quand la couche de sel est amincie alors que l’extension continue. Les structures en "sablier" se développent dans les couches syntectoniques par propagation vers le haut des failles normales et leur interférence. 2- Dans les modèles à variation latérale de la densité de la couche de décollement, l’extension dans la zone de relais parait plus accentuée dans la zone où la densité est la plus faible. Le graben connecté aux (CCP) du côté de cette zone est plus structuré. Aussi, les structures en sabliers n’apparaissent que dans cette zone à forte extension. Un diapirisme peut se produire à la jonction entre le bassin en pull-apart et le (CCP) de ce même côté. Une analyse de Corrélation d’Images Numériques appliquée à des modèles où la densité de la couche varie latéralement, permet de renseigner de manière quantitative et illustrée, la distribution des champs de déplacement et des taux de déformation, l’évolution spatio-temporelle de la déformation ainsi que la relation entre cette évolution et la rhéologie du niveau de décollement
Analogue models for the formation of pull-apart basin have involved basal discontinuities that transmit upward the movements and stresses into the overlying cover. Here we present a series of models realized according to an innovative conceptual model that allows the formation of pull-apart basins above a viscous layer, under the sole effect of lateral movement in the cover, independently of the basement.. This work is inspired by a natural example, the El Hamma-Gabes basin, , in central Tunisia.This Basin is an extensional relay zone between two main strike-slip corridors (CCP) of a N100-110 trend. These corridors are the surface expression of the crustal shear zone called "South Tunisian Accident". They are marked by right-lateral transtensional slip during the N80 extensional episode during the Upper Cretaceous, and right-lateral transpressional kinematics during the N140 compression episode during the Neogene. These movements ensured and maintained the extension of the relay zone during both extensive and compressive tectonic events. In the relay zone the sedimentary cover is directly coupled with its pre-triassic basement, in its southern part in the absence of the upper Triassic evaporites.The sub-surface structures shows a horst-and-graben system that connect to the main strike-slip corridors (CCP). Two mega-grabens are identified: the El Hamma graben to the west and (2) the Chenchou graben to the east, separated by the J. Hallouga Horst. Each one of these grabens is internally structured into a sequence of smaller-scale horsts and grabens. In vertical sections, "hourglass" structures formed by the along-strike interconnection of grabens affecting the Upper Cretaceous series develop in the northern part of the relay zone. These structures have an amount of extension greater than that in the southern part, and seem to result from greater decoupling between the cover and basement related to the presence of U Triassic evaporitic deposits in this northern part of the relay zone.Analogue models show that: 1- When a basal viscous layer (silicone) is uniformly distributed across the entire relay zone, the pull-apart basin that forms comprises two grabens, each one connected to the frontal end of one of the (CCP). The boundary faults of these structures have curved traces. Their obliquity is that of Riedel-R-type faults at the junction to the (CCP), and becomes accentuated to take the orientation of Riedel-R'-type faults, away from it. Diapirs occur locally along the graben axes. Restoration of the deformation stages allows us to evidence three successive stages of diapirism: reactive stage associated with the opening of the graben, active and then passive synkinematics. Collapse of the diapir roof occurs at an advanced stage of deformation once the salt layer is depleted but extension continues. The "hourglass" structures develop in the syntectonic layers by upward propagation of normal faults and their interference.2 - In models with lateral density change in the décollement’s density and viscosity, the amount of extension in the relay zone appears to be greater in the area having the lowest density. The graben connected to the (CCP) on the side of this zone is more structured. Also, hourglass structures appear only in this high extension zone. There, diapirism may occur at the junction between the pull-apart basin and the (CCP) on this same side.A Digital Images Correlation analysis applied to models where the density of the layer varies, allowed us to highlight, in a quantitative and illustrated way, the distribution of the displacement fields and of the deformation rate, its spatio-temporal evolution as well as the relation between this evolution and the rheology of the detachment level

Internet facilita l'accés als ciutadans a un volum astronòmic de dades i d’intercanvis comunicatius, però la qualitat del que es publica és diversa i el rol dels intermediaris tradicionals s’ha alterat. En conseqüència, les bases epistèmiques del coneixement social s'estan transformant. Per aquest motiu esdevé necessari abordar els processos mitjançant els quals les audiències avaluen la informació digital. Aquest treball indaga en l'ús de la noció de credibilitat com a eina de cognició social que legitima la informació de segona mà i contribueix a transformar dades en coneixement. L'estudi de la credibilitat és complex perquè el seu significat és ambigu, polisèmic i incorpora una gran variabilitat en funció del tipus de coneixement on s'aplica i d'altres factors contextuals. Tot i això, un punt comú és que la idea de credibilitat està condicionada per allò que s'accepta com a veritat. Aquesta tesi analitza les pràctiques i les representacions discursives de les audiències entorn a tres àmbits temàtics –salut, economia i turisme– que se situen en una escala metafòrica de descripció del coneixement com a tancat, semi-obert i obert. Per fer-ho, ha emprat una metodologia qualitativa combinant les tècniques de l'entrevista semi-estructurada i l'observació a través del protocol de pensament en veu alta. Els resultats aporten itineraris de processament de la informació variats i condicionats pels discursos del coneixement hegemònic en els diferents camps temàtics. Alhora permeten copsar certes pràctiques comunes de l'avaluació de la informació que caminen cap a representacions d'autosuficiència informativa dels usuaris. L'aportació original del treball és una definició de credibilitat que supera els problemes d'ambigüitat teòrica associats al terme en la literatura científica i en la proposició d'un model teòric processual.
Internet facilita el acceso a los ciudadanos a un volumen astronómico de datos y de intercambios comunicativos, pero la calidad de lo que se publica es diversa y el rol de los intermediarios tradicionales se ha alterado. En consecuencia, las bases epistémicas del conocimiento social se están transformando. Por este motivo se hace necesario abordar los procesos mediante los cuales las audiencias evalúan la información digital. Este trabajo indaga en el uso de la noción de credibilidad como herramienta de cognición social que legitima la información de segunda mano y contribuye a transformar datos en conocimiento. El estudio de la credibilidad es complejo porque su significado es ambiguo, polisémico e incorpora una gran variabilidad en función del tipo de conocimiento donde se aplica y de otros factores contextuales. Sin embargo, un punto común es que la idea de credibilidad está condicionada por lo que se acepta como verdad. Esta tesis analiza las prácticas y las representaciones discursivas de las audiencias en torno a tres ámbitos temáticos -salud, economía y turismo- que se sitúan en una escala metafórica de descripción del conocimiento como cerrado, semi-abierto y abierto. Para ello, ha empleado una metodología cualitativa combinando las técnicas de la entrevista semi-estructurada y la observación a través del protocolo de pensamiento en voz alta. Los resultados aportan itinerarios de procesamiento de la información variados y condicionados por los discursos del conocimiento hegemónico en los diferentes campos temáticos. Asimismo permiten captar ciertas prácticas comunes de la evaluación de la información que caminan hacia representaciones de autosuficiencia informativa de los usuarios. La aportación original del trabajo es una definición de credibilidad que supera los problemas de ambigüedad teórica asociados al término en la literatura científica y en la proposición de un modelo teórico procesual.
Using the internet as a source of information is crucial to lots of people in contemporary societies. Its open and decentralized structure makes the access to data and communicative exchanges dramatically easy. The quality of what is published is diverse and the role of traditional intermediaries is altered. Consequently, the epistemic underpinnings of social cognition are changing. Therefore, addressing the processes by which audiences evaluate digital information has become a necessity. This work addresses the use of credibility as a tool for social cognition from a point of view beyond the deterministic sublimation of computers as symbolic objects of knowledge. Credibility legitimates second-hand information and it is essential for data to become knowledge. Researching credibility is very complex because its meaning is ambiguous, polysemic and includes a great variability according to the type of discipline where it is applied and other contextual factors. However, there is a consensus on the claim that credibility is conditioned by representations of what people accept as the truth. This dissertation analyses discursive representations of credibility assessments among a variety of internet audiences inside three topic domains: health, economy and tourism. This research design is influenced by a metaphoric description of knowledge in each domain as closed, semi-open and open, respectively. A qualitative methodology approach has been used, based on semi-structured interviews and observation. The last technique is a tailored adaptation of the think aloud protocol employed in usability research. Results provide a set of varied pathways of information processing that are influenced by discourses of hegemonic knowledge in the selected topic areas. Besides, they allow establishing some common habits that are close to representations of self-sufficiency in the evaluation of credibility. This self-sufficiency is built on access to primary information (raw data or testimonials) that is interpreted according to reliability criteria. The original contribution of this dissertation consists of: 1) a definition of credibility that overcomes the theoretical problems of ambiguity reported by scientific literature, 2) the proposition of a processual model for credibility assessment.

Introducción Aunque la Práctica Basada en la Evidencia mejora la calidad de los cuidados existe una falta de implementación de la misma en el ámbito de Atención Primaria (AP). El objetivo de este estudio es explorar los factores que influyen en el uso implementación de EBE en AP de Baleares. Contenido de la investigación En una primera fase se diseñó un estudio observacional transversal multicéntrico utilizando los cuestionarios PES-NWI, que valora el entorno para una PBE, y el EBPQ que valora los conocimientos, uso y actitudes de las enfermeras hacia la PBE. Posteriormente se realizó un estudio cualitativo en el que se realizaron cinco grupos de discusión desde una perspectiva fenomenológica. Conclusión La actitud de las enfermeras de AP hacia la EBE es muy positiva pero no se sienten apoyadas por la organización, por lo que sería importante que las instituciones realizasen una gestión más profesional y menos politizada que facilitara el uso e implementación de EBE. Bibliografía Brown, C.E., Wickline, M.A., Ecoff, L., Glaser, D., 2008. Nursing practice, knowledge, attitudes and perceived barriers to evidence-based practice at an academic medical center. Journal of Advanced Nursing 65 (2), 371-381. Fineout-Overholt, E., Williamson, K.M., Gallagher-Ford, L., Melnyk, B.M., Stillwell, S.B., 2011. Evidence-Based Practice, Step By Step: Following the Evidence: Planning for Sustainable Change. AJN The American Journal of Nursing 111 (1), 54. Thompson, D.S., Estabrooks, C.A., Scott-Findlay, S., Moore, K., Wallin, L., 2007. Interventions aimed at increasing research use in nursing: a systematic review. Implementation Science 2 (1), 15. Pericàs, J., González, S., De Pedro, J., Morales, J. M., & Bennasar, M. (2014). Perception of Spanish primary healthcare nurses about evidence-based clinical practice: a qualitative study. International Nursing Review, 61(1), 90-98. doi: 10.1111/inr.12075
Introducció Encara que la Pràctica Basada en l'Evidència millora la qualitat de les cures, hi ha una manca d'implementació de la mateixa en l'àmbit d'Atenció Primària (AP). L’objectiu d’aquest estudi és explorar els factors que influeixen en l’ús i l’ implementació d’EBE en AP de Balears. Contingut de la investigació En una primera fase es va dissenyar un estudi observacional transversal multicèntric utilitzant els qüestionaris PES-NWI, que valora l'entorn per a una PBE, i el EBPQ que valora els coneixements, ús i actituds de les infermeres cap a la PBE. Posteriorment es va realitzar un estudi qualitatiu en què es van realitzar cinc grups de discussió des d'una perspectiva fenomenològica. Conclusió L'actitud de les infermeres d'AP cap a l'EBE és molt positiva però no se senten recolzades per l'organització, pel que seria important que les institucions realitzessin una gestió més professional i menys polititzada que facilités l'ús i implementació d'EBE . Bibliografia Brown, C.E., Wickline, M.A., Ecoff, L., Glaser, D., 2008. Nursing practice, knowledge, attitudes and perceived barriers to evidence-based practice at an academic medical center. Journal of Advanced Nursing 65 (2), 371-381. Fineout-Overholt, E., Williamson, K.M., Gallagher-Ford, L., Melnyk, B.M., Stillwell, S.B., 2011. Evidence-Based Practice, Step By Step: Following the Evidence: Planning for Sustainable Change. AJN The American Journal of Nursing 111 (1), 54. Thompson, D.S., Estabrooks, C.A., Scott-Findlay, S., Moore, K., Wallin, L., 2007. Interventions aimed at increasing research use in nursing: a systematic review. Implementation Science 2 (1), 15. Pericàs, J., González, S., De Pedro, J., Morales, J. M., & Bennasar, M. (2014). Perception of Spanish primary healthcare nurses about evidence-based clinical practice: a qualitative study. International Nursing Review, 61(1), 90-98. doi: 10.1111/inr.12075
Introduction Although Evidence-Based Practice improves the quality of care there is a lack of implementation in Primary Health Care (PHC) services. The aim of this study is to explore the factors that influence on the use and EBN implementation in the Balearics PHC. Research content In the first phase a multicenter cross-sectional study was designed using two questionnaires, the PES-NWI which assessed the environment for EBN, and EBPQ that values knowledge, use and attitudes of nurses towards the EBN. Subsequently, a qualitative study in which five focus groups were conducted from a phenomenological perspective, was performed. Conclusion The attitude of PHC nurses towards the EBN is very positive but they don’t feel supported by the organization, it would be important that institutions should do a more professional and less politicized management to facilitate the use and implementation of EBN. Bibliography Brown, C.E., Wickline, M.A., Ecoff, L., Glaser, D., 2008. Nursing practice, knowledge, attitudes and perceived barriers to evidence-based practice at an academic medical center. Journal of Advanced Nursing 65 (2), 371-381. Fineout-Overholt, E., Williamson, K.M., Gallagher-Ford, L., Melnyk, B.M., Stillwell, S.B., 2011. Evidence-Based Practice, Step By Step: Following the Evidence: Planning for Sustainable Change. AJN The American Journal of Nursing 111 (1), 54. Thompson, D.S., Estabrooks, C.A., Scott-Findlay, S., Moore, K., Wallin, L., 2007. Interventions aimed at increasing research use in nursing: a systematic review. Implementation Science 2 (1), 15. Pericàs, J., González, S., De Pedro, J., Morales, J. M., & Bennasar, M. (2014). Perception of Spanish primary healthcare nurses about evidence-based clinical practice: a qualitative study. International Nursing Review, 61(1), 90-98. doi: 10.1111/inr.12075

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Stable drilling directions are directly affected by the in-situ stress orientations and magnitudes involved. For example, in the Gulf of Mexico delta top normal fault stress regime, where the maximum horizontal stress (σH) is margin-parallel, vertical wells are most stable. However, in-situ stress orientations are deflected around salt diapirs and have major implications for horizontal drilling risks. This study assesses the deflection of in-situ stress orientations and palaeostress orientations in close proximity to salt diapirs using 3D seismic data from the Gulf of Mexico and structural field observations from the Amadeus Basin, central Australia. Seismic interpretation of salt diapirs in the Ship Shoal seismic cube (Gulf of Mexico) reveals gravitational collapse on the flanks of the salt diapirs, implying net normal displacement. This is consistent with the hypothesis that σH becomes locally deflected sub-parallel to the salt-sediment interface. The salt diapir in the Amadeus Basin field area is within a more complex structural setting compared to the Gulf of Mexico and is associated with a large NW-SE striking thrust fault. This implies that it has reacted to north-south shortening from the Alice Springs Orogeny. Palaeostress analysis from conjugate fracture pairs in the field area reveals a large variation in orientations for σ1 and σ3. However, σ2 is consistently sub-perpendicular to bedding, thus σ1 and σ3 orientations are restricted to the plane of bedding. Evidence from both the 3D Ship Shoal seismic cube and the structural field data suggests that in-situ stress is deflected around salt diapirs. However, the results from the field structural analysis are dissimilar to seismic interpretation from the Gulf of Mexico. In-situ stress deflections along the flanks of salt diapirs are associated with complex perturbations. These deflections are dependent on the structural setting of each salt diapir and whether it is interpreted as active, passive or reactive.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Earth and Environmental Sciences, 2012

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This research is focused on the Northern Gulf of Mexico Mississippi Fan Delta. Deltas have a maximum horizontal stress margin parallel (extensional stress regime) at the delta top and a margin normal maximum horizontal stress (compressional stress regime) at the delta toe (King et al., 2010). The area of the delta with intrusive salt diapirs has significantly deflected maximum horizontal stresses around the salt diapirs. This is due to the contrasting geomechanical rock properties between the salt and the deltaic sediments (Zhang, 1994). A 3D seismic survey of the area with vertical salt diapirs was provided by Western Geoco. The seismic data was interpreted for the top salt-sediment contact and diapir related deformation of the sedimentary overburden. The interpretation identified six salt diapirs: four piercing by active diapirism and two piercing by reactive diapirism. 2D finite numerical models were built from representative sections of each salt diapir to predict the principal stress deflections within the sedimentary overburden adjacent the salt. The models of the reactive diapirs deflected the maximum principal stress parallel to the salt-sediment contact of the salt diapirs. The models of the active diapirs deflected the maximum principal stress normal to the salt-sediment contact of the salt diapirs. The stress orientations allowed for borehole stability diagrams to be produced for the stress orientation above the diapir crests, over the diapir flank and over the base salt for each diapiric style.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Earth and Environmental Sciences, 2011

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The current deformation style of active salt detachments beneath delta and deep-water fold-thrust belts in the Gulf of Mexico is poorly constrained. The combination of seismic interpretation and seismic attribute analysis provides greater resolution for identifying fault patterns that are otherwise unresolved in conventional seismic amplitude displays. These techniques are applied to the Ship Shoal and North-West Gulf Coast 3D seismic volumes, and used to investigate the geometry of low signal amplitudes within six interpreted salt diapirs. The ridge enhancement filter and similarity attributes display a strong correlation with faults and fractures observed over a range of magnitudes, and identify structural relationships between salt diapirs and the surrounding sedimentary overburden. Conventional seismic amplitude displays show salt diapirs as ductile and homogenous structures. However, this study concludes that diapirs are likely to contain interbedded resistive sequences facilitating brittle shear. Deformation styles exhibited by active salt diapirs are broadly comparable to those observed in outcrops within exhumed detachment systems. Future application of seismic attribute analysis is needed to improve the understanding of deformation styles exhibited by similar submarine structures.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 2014

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Salt basins are complex structural systems, showing genetic relationships between salt structures, faults, and variable sediment depositional patterns. The dynamics of salt-fault interaction, the role of shale deformation, and the influence of salt evacuation on surface features have been poorly understood. A link between all these processes is the throw history of faults adjacent to and within a salt basin. In this dissertation, I interpret industry well logs and 3D seismic data from the Terrebonne Salt Withdrawal Basin (TSWB) of southeastern Louisiana, to understand these processes. The methodology includes the use of fault throw maps, throw variations along strike and with depth, and sediment expansion indices to understand fault kinematics adjacent to sediment loads and mobile material, i.e., salt or shale. I address the histories of three faults along the northern margin of the TSWB: the Lake Boudreaux, Montegut, and Isle de Jean Charles faults. Each shows Miocene and Quaternary active phases correlated with sediment loading, separated by relative inactivity during the Pliocene. The pattern of Quaternary activity and the surface projections of these faults are consistent with a fault-controlled pattern of wetland loss, suggesting that faults in southeastern Louisiana are active. Isle de Jean Charles fault and the Lake Boudreaux fault interact with the Bully Camp and Lake Barre Salt stocks, respectively. Each stock is interpreted to have grown by a different diapiric mechanism, consistent with different spatial patterns of throw variation on the two faults, despite similar temporal histories. Throw on the Isle de Jean Charles fault increases towards the Bully Camp stock, suggesting deformation inside and outside the stock. In contrast, a decrease in the throw on the Lake Boudreaux fault and an increase in diameter of the Lake Barre stock indicate that deformation exists only within the stock. Additionally, this dissertation considers throw patterns along the southern margin of the TSWB, showing that faults linking the Dog Lake and Caillou Island salt stocks are affected by shale deformation adjacent to salt. These results show that studies of fault-related subsidence and wetland loss in coastal Louisiana need to include observations from nearby salt structures.
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Akinbobola Akintomide

Water flow and geochemical processes within the unsaturated zone (UZ) in two distinct types of karst environment were investigated using natural tracers (chemistry, stable isotopes 13 C, 18 O, 2 H, and 3 H, 14 C, 87 Sr/86 Sr). The extent of horizontal flow component and the response of drip water chemistry to recharge events were examined in the Moravian Karst (Czech Republic), while the character of water flow and its chemistry were studied in salt diapirs in southeastern part of the Zagros mountains (Iran). Under the conditions of well-developed epikarst, the horizontal flow component, defined as Hmax/T (Hmax = horizontal migration component, T - thickness of VZ) typically reaches values of 0.1 - 0.6 (Moravian and Slovenian Karst). However, in areas where epikarst was stripped off by glacial or human activity, the proportion of horizontal flow component is far greater (Hmax/T 1.6 - 24). This parameter is vital for the design of water source protection zones above caves. Nitrate mean residence time in 120 m thick VZ of the Moravian karst exceeded 16 years. The VZ above the Ochoz Cave (Moravian Karst) represents a semi-open to open system with respect to soil CO2. Under a high drip rate (high flow), the event water only made 5% of the total. During the year, water degassing and so called prior...