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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
171

Cognitive Variability in High-functioning Individuals & its Implications for the Practice of Clinical Neuropsychology

Jeffay, Eliyas 01 January 2011 (has links)
Knowledge of the literature pertaining to patterns of performance in normal individuals is essential if we are to understand intraindividual variability in neurocognitive test performance in neuropsychiatric disorders. Twenty-five healthy individuals with a high-level of education were evaluated on a short neuropsychological battery which spanned several cognitive domains. ---Results indicated that cognitive abilities are not equally distributed within a sample of healthy, high-level functioning individuals. This may be of interest to neuropsychologists who might base clinical inference about the presence of cerebral dysfunction, at least in part, on marked variation in a patient’s level of cognitive test performance. The practice of deductive reasoning in clinical neuropsychology may be prone to false-positive conclusions about cognitive functioning in neuropsychiatric disorders where base-rates of cognitive impairments are low and pre-existing educational achievements are high.
172

Response of Benthic Microalgal Community Composition at East Beach, Galveston Bay, Texas to Changes in Salinity and Nutrients

Lee, Alyce R. 2009 May 1900 (has links)
Benthic microalgal community composition on an ephemerally submerged sandflat at East Beach, Galveston Island, Texas was studied to determine the spatial and temporal variability of total biomass and community composition and its responses to experimental manipulations of two environmental factors (salinity and nutrients). Four field studies were conducted between August 2004 and February 2005. The community consisted of two major algal groups, diatoms, and cyanobacteria with two less abundant groups, green algae, and phototrophic bacteria. Spatial variability showed that patch sizes of 12 - 25 m were detected over larger scales with smaller scale (cm) patches of approximately 28 - 201 cm^-2 contained within the larger patches. The second study examined the spatio-temporal variability of BMA over a 21-month period in a 1,000 m^2 area. Sampling location and date explained a significant amount of the variability in the abundances of algal groups, which were positively correlated with the water content of the sediments and negatively correlated with temperature (sediment and water). All of the algal groups showed a seasonal pattern with higher abundances measured in the winter months and lower abundances found during the summer. BMA biomass (100 mg Chl a m^-2 or greater) maxima occurred at temperatures less than 22 degrees C and sediment water content greater than 15% (g water g sediment^-1). BMA response to different salinities and nutrient (N+P) amended sediments was assessed in four bioassays conducted over a 6-month period (Aug. 2004, Oct. 2004, Dec. 2004, and Feb. 2005). In the salinity study, the treatments that were either 100% or partially diluted with deionized water had the lowest BMA biomass over all. Chlorophyll a and fucoxanthin were significantly affected by salinity with higher abundances found in salinities that averaged 15 with a preference for salinities greater than 22. Chlorophyll b was affected by salinity with higher abundances measured in the treatments with lowest salinity (DL and DI); and was affected by the time of year. This would suggest that this algal group prefers an environment with salinity less than 2 but can easily adapt to environments with higher salinities. BMA abundances were not significantly affected by the nutrient amended sediment, but were significantly affected by stations with higher water content, and during the cooler months (Dec. 2004 and Feb. 2005).
173

Variabilitätsextraktion aus makrobasierten Software-Generatoren

Baum, David 19 March 2014 (has links) (PDF)
Die vorliegende Arbeit beschäftigt sich mit der Frage, wie Variabilitätsinformationen aus den Quelltext von Generatoren extrahiert werden können. Zu diesem Zweck wurde eine Klassifizierung von Variablen entwickelt, die im Vergleich zu bestehenden Ansätzen eine genauere Identifikation von Merkmalen ermöglicht. Zudem bildet die Unterteilung die Basis der Erkennung von Merkmalinteraktionen und Cross-tree-Constraints. Weiterhin wird gezeigt, wie die gewonnenen Informationen durch Merkmalmodelle dargestellt werden können. Da diese auf dem Generator-Quelltext basieren, liefern sie Erkenntnisse über den Lösungsraum der Domäne. Es wird sichtbar, aus welchen Implementierungskomponenten ein Merkmal besteht und welche Beziehungen es zwischen Merkmalen gibt. Allerdings liefert ein automatisch generiertes Merkmalmodell nur wenig Erkenntnisse über den Lösungsraum. Außerdem wurde ein Prototyp entwickelt, der eine Automatisierung des beschriebenen Extraktionsprozesses ermöglicht.
174

Statistical methodologies for modelling the impact of process variability in ultra-deep-submicron SRAMs / Méthodologie statistique de modélisation pour l'optimisation de l'offre SRAM 'basse puissance'

Akyel, Kaya Can 17 December 2014 (has links)
La miniaturisation des transistors vers ses ultimes limites physiques a exacerbé les effets négatifs qui sont liées à la granularité de la matière. Plusieurs nouvelles sources de variabilités affectent les transistors qui, bien qu'identiquement dessinés, montrent des caractéristiques électriques qui sont variables entre eux et entre différents moments de leur utilisation. Les circuits de mémoire SRAM, qui sont conçues avec des règles de dessin parmi le plus agressives et contiennent un nombre de transistors très élevé, sont menacés en particulier par ce phéomène de variabilité qui représente le plus grand obstacle non seulement pour la réduction de la surface d'un point mémoire SRAM, mais aussi pour la réduction de son tension d'alimentation. L'optimisation des circuits SRAM est devenue une tache cruciale afin de répondre à la fois aux demandes d'augmentation de densité et de la réduction de la consommation, donc une méthodologie statistique permettant de modéliser an amont l'impact de la variabilité à travers des simulations SPICE est devenue un besoin obligatoire. Les travaux de recherches présentés se concentrent sur le développement des nouvelles méthodologies pour la simulation des points mémoires sous l'impact de la variabilité, dans le but d'accomplir une modélisation précise de la tension d'alimentation minimale d'un SRAM quelques soit les conditions d'opérations. La variabilité dynamique liée au bruit RTS qui cause le changement des caractéristiques électrique des transistors au cours de leurs opérations est également étudiée avec un effort particulier de modélisation. Ce travail a donné lieu à de nombreuses publications internationales et à un brevet. Aujourd'hui cette méthodologie est retenue par STMicroelectronics et est utilisé dans la phase d'optimisation des plans mémoires SRAM. / The downscaling of device geometry towards its physical limits exacerbates the impact of the inevitable atomistic phenomena tied to matter granularity. In this context, many different variability sources raise and affect the electrical characteristics of the manufactured devices. The variability-aware design methodology has therefore become a popular research topic in the field of digital circuit design, since the increased number of transistors in the modern integrated circuits had led to a large statistical variability affecting dramatically circuit functionality. Static Random Access Memory (SRAM) circuits which are manufactured with the most aggressive design rules in a given technology node and contain billions of transistor, are severely impacted by the process variability which stands as the main obstacle for the further reduction of the bitcell area and of its minimum operating voltage. The reduction of the latter is a very important parameter for Low-Power design, which is one of the most popular research fields of our era. The optimization of SRAM bitcell design therefore has become a crucial task to guarantee the good functionality of the design at an industrial manufacturing level, in the same time answering to the high density and low power demands. However, the long time required by each new technology node process development means a long waiting time before obtaining silicon results, which is in cruel contrast with the fact that the design optimization has to be started as early as possible. An efficient SPICE characterization methodology for the minimum operating voltage of SRAM circuits is therefore a mandatory requirement for design optimization. This research work concentrates on the development of the new simulation methodologies for the modeling of the process variability in ultra-deep-submicron SRAMs, with the ultimate goal of a significantly accurate modeling of the minimum operating voltage Vmin. A particular interest is also carried on the time-dependent sub-class of the process variability, which appears as a change in the electrical characteristics of a given transistor during its operation and during its life-time. This research work has led to many publications and one patent application. The majority of findings are retained by STMicroelectronics SRAM development team for a further use in their design optimization flow.
175

An investigation of the diagnostic utility of intraindividual variability in attention deficit/hyperactivity disorder: an ex-Gaussian approach.

Ali, Sheliza 23 July 2020 (has links)
This dissertation aimed to investigate the utility of the ex-Gaussian approach to estimating intraindividual variability (IIV) of response times (RT) in diagnosing attention deficit/hyperactivity disorder (ADHD) in children ages 6 to 13 years old. Higher IIV is consistently noted in children with ADHD, but also with other disorders commonly associated with impairments in attention. Firstly, the relationship between IIV and attention abilities was investigated both in relation to parent ratings and participants’ objective performance. Secondly, IIVs utility as an objective measure for supplementing behavioural ratings in the diagnosis of ADHD, a diagnosis which is currently primarily assigned based on informant interviews and ratings of attention, was assessed. Participants included 46 children with ADHD and 58 children without ADHD. Children completed computerized tasks to estimate IIV and assess inattention and hyperactivity/impulsivity. Parents completed questionnaires aimed at assessing attention and hyperactive/impulsive behaviours of participants. Analyses revealed that IIV was predictive of parent ratings of inattention and hyperactivity/impulsivity as well as the number of omission errors made by participants. Regarding diagnostic utility, IIV significantly predicted group membership (ADHD vs Control). However, IIV did not improve diagnostic accuracy when parent ratings were used, such that parent ratings were superior at determining diagnosis. Overall, current results support the use of IIV, based on the ex-Gaussian approach, as an objective measure of attention problems such that it appears to be superior to omission errors on sustained attention CPT-type tasks. Additionally, while parent ratings of attention impairment remain the best predictor of ADHD diagnostic status, IIV may be helpful in determining when further assessment is required in the absence of those ratings. / Graduate / 2021-06-17
176

Variability in the Natural World: An Analysis of Variability in Preschool Play

Armshaw, Jared T 08 1900 (has links)
Children acquire many skills through play. These range from fine and gross motor skills, social skills, problem-solving, to even creativity. Creativity or creative engagement is frequently a component in early preschool curricula. A pivotal repertoire to engage in behaviors deemed creative, such as art, storytelling, problem-solving, and the like, is the ability to vary one's responses regardless of the specific repertoire. Researchers have developed methods to produce response variability. However, notwithstanding the significant contributions from the literature for prompting response variability, it remains unclear how much variation in responding is socially appropriate. To fill this research gap, the purpose of this study is to characterize and understand the different ways preschool children commonly interact with the activities and materials present in a preschool classroom. In our study, we assessed children's repeat item interactions, novel item interactions, and time allocation across seven concurrently available activity centers. A multifarious pattern for item interactions emerged across children. Some children had restricted levels of novel item and center interactions, while other children had more varied novel item and center interactions. However, the variance in interactions was predominantly controlled by the center type. This study bolsters our understanding of variability and creativity within a school setting, but more importantly, it informs the task of selecting goals for applied practice with children who have restricted play or interests.
177

Morfološka varijabilnost vrsta roda Anacamptis Rich. (Orchidoideae, Orchidaceae) na području Balkanskog poluostrva i Panonske nizije / Morphological variability of species of the genusAnacamptis Rich. (Orchidoideae, Orchidaceae) in the Balkan Peninsula and the Pannonian Plain

Radak Boris 04 November 2019 (has links)
<p>Pored rodova evropskih orhideja koji se odlikuju velikim stepenom diverzifikacije, kao i značajnim brojem novoopisanih vrsta, kao &scaron;to su <em>Ophrys </em>ili<em> Epipactis,</em> rod<em> Anacamptis </em>je ostao poprilično zapostavljen u orhidolo&scaron;kim istraživanjima. Na predstavnicima ovog roda uglavnom su vr&scaron;ena molekularna istraživanja, u kojima je bio uključen i veći broj drugih rodova.Takođe, urađene su i opsežne studije, ali samo na pojedinim vrstama. Morfolo&scaron;ka istraživanja su bila veoma retka i uz par uzuzetaka, ograničena na geografski mala područja i na jednu ili nekoliko morfolo&scaron;ki sličnih vrsta. Analiza morfolo&scaron;ke varijabilnosti ovolikog broja taksona roda<em> Anacamptis</em> na geografski relativno velikom području kakvo je Balkansko poluostrvo, kao i deo Panonske nizije koji se oslanja na njega, do&nbsp; sada nije bilo sprovedeno. Morfolo&scaron;kim analizama bili su podvrgnuti gotovo svi predstavnici ovog roda u rangu vrste i podvrste, a koji se javljaju na području kopnenog dela Balkanskog poluostrva, kao i južnog oboda Panonske nizije. Sprovedene su jednostrane i uporedne morfolo&scaron;ke analize sa detaljnomobradom podataka metodama bazične, univarijantne i multivarijantne statistike. Do sada najvećim istraživanjem taksona roda<em> Anacamptis</em>, po broju obrađenih jedinki i području na kom je sprovedeno, bila je obuhvaćena 2001 jedinka iz 185&nbsp; populacija. Analizirane su prirodne populacije, ali i materijal iz Herbarijuma BUNS. Ukupno je definisano 69 morfolo&scaron;kih karaktera, kvantitativnih i kvalitativnih, a među njima su traženi oni koji imaju potencijalno diferencijalni karakter između opisanih vrsta i infraspecijskih taksona. Analize su obuhvatile i interpopulacionu morfolo&scaron;ku varijabilnost u okviru svakog taksona, a u cilju uočavanja postojanja određenih geografskih obrazaca njenih promena. Morfolo&scaron;ki karakteri koji su se u sprovedenim analizama pokazali kao taksonomski informativni, iskori&scaron;ćeni su za formiranje dihotomog ključa za determinaciju taksona roda <em>Anacamptis</em> prisutnih na istraživanom području. Analizama je utvrđen veliki broj karaktera koji su statistički značajno različiti između analiziranih populacija, podvrsta i vrsta. Većina karaktera je pokazala umerenu ili nisku varijabilnost, a u retkim slučajevima i povećanu. Karakteri cveta međusobno su statistički značajno korelisani,većina slabo do umereno, dok su oni na listićima kacige, kao i između labeluma i drugih delova cveta jako do izrazito jako povezani. Jedini takson koji nije pokazao nikakvu infraspecijsku diferencijaciju, a koji se odlikuje velikom unutari interpopulacionom varijabilno&scaron;ću je<em> A. pyramidalis</em>. Iz istog razloga je pokazano kao neosnovano izdvajanje jedinki iz različitih delova njegovog areala u do sada opisane infraspecijske oblike. Potvrđena je niska morfolo&scaron;ka varijabilnost uskorasprostranjene vrste <em>A. boryi.</em> Kod svih preostalih istraživanih taksona utvrđeno je postojanje određenih obrazaca geografske interpopulacione varijabilnosti i infraspecijske struktuiranosti.Populacije <em>A. laxiflora</em> subsp. <em>laxiflora </em>mogu se podeliti na jadranske i kontinentalne, pri čemu najzapadnije pokazuju i najmanje vrednosti analiziranih karaktera. <em>A. coriophora </em>subsp.<em> fragrans </em>se pokazala kao manje varijabilnom od tipske podvrste, ali je u okviru nje kao zaseban takson izdvojen var. <em>hermae </em>kao fenolo&scaron;ki, ekolo&scaron;ki i morfolo&scaron;ki odvojen u odnosu na ostaleispitivane populacije. Tipska podvrsta pokazuje obrazac variranja ukupne morfolo&scaron;ke varijabilnosti u pravcu zapad-istok. Kao karakteri koji su najznačajniji za diferencijaciju podvrsta vrste<em> A. palustris</em> izdvojeni su dužina i &scaron;irina brakteje, stepen diferenciranosti labeluma na režnjeve, kao i dubina sinusa koja ih razdvaja. Populacije<em> A. palustris</em> subsp. <em>elegans</em> moguće je podeliti na tri geografski i morfolo&scaron;ki definisane grupe &ndash; istočnobalkansku, zapadnobalkansku i periferne populacije sa severa Srbije i iz Slovenije. Kao diferencijalni karakteri između taksona sekcije <em>Laxiflorae</em> pokazali su se odnos između dužine plodnika i brakteje, kao i dužina srednjeg režnja labeluma. Vrsta<em> A. morio </em>je po prvi put jasno morfolo&scaron;ki i arealno podeljena na dve podvrste na istraživanom području. Podvrste pokazuju velika preklapanja vrednosti morfolo&scaron;kih karaktera, ali se obe odlikuju specifičnim karakteristikama cveta, pre svega labeluma na osnovu kojih ih je moguće razlikovati. Definisani su areali podvrsta<em> A.morio </em>na istraživanom području &ndash; tipska podvrsta je prevashodno severnija i zapadnija, dok je subsp.<em> caucasica </em>južnija i istočnija. Prvu odlikuju krupniji cvetovi, bubrežastih labeluma sa srednjim režnjem koji ne prevazilazi značajno dužinu bočnih, dok je druga sa sitnijim cvetovima i snažno isturenim srednjim režnjem. Obe podvrste mogu se podeliti na grupe populacija sa jasno definisanim geografskim raspostranjenjem. Vrsta <em>A. papilionacea </em>je po prvi put morfolo&scaron;ki istaživana na većem broju primeraka, a ne prostim poređenjem pojedinačnih primeraka iz različitih delova areala. Pokazana je morfolo&scaron;ka diferenciranost na dve podvrste &ndash; tipsku i subsp. aegaea, koje se jasno morfolo&scaron;ki razlikuju i zauzimaju različite delove areala vrste. U okviru subsp. <em>papilionacea</em> registrovan je klinalni raspored morfolo&scaron;ke varijabilnosti u pravcu sever-jug. Registrovana su i tri hibrida, nova za područje pojedinih zemalja &ndash; A. <em>&times; gennarii</em> (Severna Makedonija),A. <em>&times; parvifolia</em> (Crna Gora) i A. &times; <em>timbali</em> (Srbija). Hibridi pokazuju generalnu morfolo&scaron;ku intermedijarnost u odnosu na roditelje, ali se odlikuju i novim stanjima karaktera, nezabeleženim kod roditeljskih taksona. Slični obrasci morfolo&scaron;ke varijabilnosti, kako na interpopulacionom nivou pojedinih vrsta, ali iizmeđu podvrsta svake istraživane vrste, pokazuju jasnu vezu između istraživanih taksona i jo&scaron; jednom opravdavaju njihovo zajedničko grupisanje u rod<em> Anacamptis.</em></p> / <p>Unlike the highly diversified and species-rich genera of European orchids, such as<em> Ophrys </em>or <em>Epipac</em>tis, the genus <em>Anacamptis </em>has remained quite neglected in orchidological research. Representatives of this genus, together with many others genera, were investigated mainly by molecular methods. Also, extensive studies have been done, but only on specific species. Morphological studies were very rare, and with a few exceptions, limited to geographically small areas and one or more morphologically similar species. Analysis of the morphological variability of so many taxa of the genus <em>Anacamptis</em>, in a is, in a geographically relatively large area such as the Balkan Peninsula, as geographically relatively large area such as the Balkan Peninsula, as well as the southern part of the Pannonian Plain, has not been conducted so far. Morphological analyses were<br />performed on almost all representatives of this genus,in the species and subspecies rank , occurring in the Balkan Peninsula mainland, as well as in the southern perimeter of the Pannonian Plain. Comparativemorphological analyses were conducted using the methods of basic, univariate and multivariate statistics.So far, the largest study of the genus&nbsp; nacamptis, by the number of processed individuals and the area in which it was conducted, included 2001 individuals from 185 populations. Natural populations and&nbsp; material from the BUNS Herbarium were analyzed. A total of 69 morphological characters, quantitative and&nbsp; qualitative, were defined, and those that have a potentially differential character among analyzed species and infraspecific taxa were selected. The analyzes also included interpopulation morphological variability within each taxon, to identify the existence of specific geographic patterns of its changes. The morphological characters that proved to be taxonomically informative, were used to form the dichotomous key for the determination of the genus Anacamptis members, presented in the study area. The analyzes identified a large number of characters that were statistically significantly different between the analyzed populations, subspecies, and species. Most of the characters showed moderate or low variability, and in rare cases increased variability. Flower&rsquo;s characters were statistically significantly correlated with each other, most of them weakly to moderately, while those of the sepals and petals, as well as between the&nbsp; labellum and other parts of the flower, were very strongly correlated. The only taxon that has not shown any infraspecific differentiation (except <em>A. boryi</em>), and which is characterized by high intra- and interpopulation variability, is A. pyramidalis. For the same reason, it has been shown as unjustified to separate individuals from different parts of species range into infraspecific forms. The low morphological variability of the narrowly distributed A. boryi was confirmed. In all other taxa studied, the existence of certain patterns of geographical interpopulation variability and infraspecific structuring was detected. <em>A. laxiflora</em> subsp. <em>laxiflora</em> populations can be divided into two groups &ndash; Adriatic and Continental, with the lowest characters values measured among the westernmost populations. <em>A. coriophora s</em>ubsp. <em>fragrans</em> proved to be less variable than the type subspecies, but within it, a new variety (var. hermae) as phenological, ecological and morphologically distinct from other studied populations was described. The typesubspecies has a transition of morphological variability in a west-east direction. The characters that are the most important for differentiation of A. palustris subspecies are the&nbsp; bract length and width, the degree of labellum differentiation into lobes, and the depth of the sinuses that separate them. Populations of A. palustris subsp. elegan<em>s </em>can be divided into three geographically and morphologically defined groups &ndash; Eastern Balkan, Western Balkan and peripheral populations from the North Serbia and Slovenia. Differential characters&nbsp; among the Laxiflorae section taxa are ration between the ovary length and bract length, as well as the labellum middle lobe length. For the first time, species <em>A. morio </em>is morphologically and geographically divided into two subspecies, in the&nbsp; study area. Analyzed subspecies have great overlapping values for many morphological characters, but both are characterized by specific flower&rsquo;s characteristics, above all labellum shape. On this basis, it is possible to distinguish them. Areals of <em>A</em>. <em>morio </em>subspecies were defined &ndash; the type subspecies is predominantly northern and western,while subsp. caucasica is southern and eastern. The first is characterized by larger flowers, renal shape labellum with a median lobe that does not exceed significantly the length of the lateral ones, while the second subspecies has smaller flowers and strongly projecting the median lobe. Both subspecies can be divided into groups of populations that have clearly defined geographical distribution. For the first time, A. papilionacea was morphologically investigated on a larger number of specimens, unlike previous&nbsp;&nbsp; researches in which individual specimens from different parts of the range were simply compared. Morphological differentiation into two subspecies was shown &ndash; type and subsp. aegaea. They are morphologically distinct and occupy different parts of the species range. Within the subsp. papilionacea a clinal distribution of morphological variability in the north-south direction was recorded. Three taxa of hybrid origin, new for the area of North Macedonia (A.<em> &times; gennari</em>i), Montenegro (A. <em>&times; parvifolia</em>) and Serbia (A. &times; t<em>imbali</em>) were registered. Hybrids exhibit a general morphological intermediacy between parents but are also distinguished by new character states that were not observed in<br />parental taxa. Similar patterns of morphological variability, both at the interpopulation level ofindividual species and between the subspecies of each species studied, show a clear relationship between the studied taxa and once again justify their grouping into the genus <em>Anacamptis.</em></p>
178

Morfologická variabilita kamerunských strdimilů / Morphological variation of Cameroonian sunbirds

Bovšková, Denisa January 2017 (has links)
5 Abstract Morphological traits give information about the adaptations of the studied species, the resources, which it uses, and they can generally tell us about the use of ecological space. Intraspecific morphological variability reflects various adaptations of local populations thus variability reflect different way of life. The subject of this thesis is an ecologically interesting group of specialized tropical songbirds - Sunbirds (Nectarinidae). The taxon exhibits number of adaptations to specific food collecting a combination of nectarivory and insect hunting. I focused here on the intraspecific variability of three species (Cyanomitra oritis, Cinnyris reichenowi and C. bouwieri) living in different habitats in Cameroon. The aim of this work was to find out in what morphological characters are this species sexually dimorphic. Furthermore, if their populations living in remote locations differ? Finally, if all studied species show similar trend of intraspecific variability of the traits, which could have common ecological causes. The following traits were measured: wing and tail feather length, beak dimensions, total body weight and other characters. The analysis is based on field data collected between 2003 and 2015 and museum collections. Overall, we collect information about ca. 1200 individuals for...
179

ASSESSING THE SIGNIFICANCE OF CLIMATE VARIABILITY ON GROUNDWATER RISE AND SEA LEVEL CHANGES

Joshi, Neekita 01 June 2021 (has links)
Climate variability is important to understand as its effects on groundwater are complex than surface water. Climate association between Groundwater Storage (GWS) and sea level changes have been missing from the Intergovernmental Panel on Climate Change, demanding a requisite study of their linkage and responses. The current dissertation is primarily focused on the ongoing issues that have not been focused on the previous literatures. Firstly, the study evaluated the effects of short-term persistence and abrupt shifts in sea level records along the US coast by utilizing popular robust statistical techniques. Secondly, the study evaluated the variability in groundwater due to variability in hydroclimatic variables like sea surface temperature (SST), precipitation, sea level, and terrestrial water storage. Moreover, a lagged correlation was also analyzed to obtain their teleconnection patterns. Lastly, the relationship between the groundwater rise and one of the most common short-term climate variability, ENSO was obtained. To accomplish the research goals the current dissertation was subdivided into three research tasks.The first task attempted to answer a major question, Is sea level change affected by the presence of autocorrelation and abrupt shift? This question reflects the importance of trend and shift detection analysis in sea level. The primary factor driving the global sea level rise is often related to climate change. The current study investigates the changes in sea level along the US coast. The sea level records of 59 tide gauge data were used to evaluate the trend, shift, and persistence using non-parametric statistical tests. Mann-Kendall and Pettitt’s tests were utilized to estimate gradual trends and abrupt shifts, respectively. The study also assessed the presence of autocorrelation in sea level records and its effect on both trend and shift was examined along the US coast. The presence of short-term persistence was found in 57 stations and the trend significance of most stations was not changed at a 95% confidence level. Total of 25 stations showed increasing shift between 1990–2000 that was evaluated from annual sea level records. Results from the current study may contribute to understanding sea level variability across the contiguous US. The second task dealt with variability in the Hydrologic Unit Code—03 region. It is one of the major U.S. watersheds in the southeast in which most of the variability is caused by Sea Surface Temperature (SST) variability in the Pacific and Atlantic Ocean, was identified. Furthermore, the SST regions were identified to assess its relationship with GWS, sea level, precipitation, and terrestrial water storage. Temporal and spatial variability were obtained utilizing the singular value decomposition statistical method. A gridded GWS anomaly from the Gravity Recovery and Climate Experiment (GRACE) was used to understand the relationship with sea level and SST. The negative pockets of SST were negatively linked with GWS. The identification of teleconnections with groundwater may substantiate temporal patterns of groundwater variability. The results confirmed that the SST regions exhibited El Niño Southern Oscillation patterns, resulting in GWS changes. Moreover, a positive correlation between GWS and sea level was observed on the east coast in contrast to the southwestern United States. The findings highlight the importance of climate-driven changes in groundwater attributing changes in sea level. Therefore, SST could be a good predictor, possibly utilized for prior assessment of variabilities plus groundwater forecasting. The primary goal of the third task is to better understand the effects of ENSO climate patterns on GWS in the South Atlantic-Gulf region. Groundwater issues are complex and different studies focused on groundwater depletion while few emphasized, “groundwater rise”. The current research is designed to develop an outline for assessing how climate patterns can affect groundwater fluctuation, which might lead to groundwater rise. The study assessed the effect of ENSO phases on spatiotemporal variability of groundwater using Spearman Rank Correlation. A significant positive correlation between ENSO and GWS was observed. An increasing trend was detected in GWS where most grids were observed in Florida by utilizing the non-parametric Mann-Kendall. A positive magnitude of the trend was also detected by utilizing Theil-Sen’s Slope method with high magnitude in the mid-Florida region. The highest GWS anomalies were observed in the peak of El Niño events and the lowermost GWS was observed during La Niña events. Furthermore, most of the stations were above normal groundwater conditions. This study provides a better understanding of the research gap between groundwater rise and ENSO.
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Taxonomy of short-term within-person variability in job performance Review and Empirical Assessment

Stuti Thapa Magar (9183089) 05 August 2023 (has links)
<p>Recent theoretical works and methodological advancements in organizational psychology have highlighted the necessity of a within-person perspective on organizational constructs. Past research suggests that focusing on within-person variation as an outcome can inform us of organizational processes that would not be possible with a static or mean-level approach. As such, the study of performance, on both intra- and inter-individual levels, is incomplete without addressing the nature of intraindividual variations and predictors of their short-term changes (i.e., dynamics). To address this, I first compiled a list of dynamic features from affective, personality, and cognitive dynamics and used it to develop a taxonomy of short-term performance variations (e.g., variability, inertia, stability, diurnal variation) and then conducted a systematic review of empirical works on performance variability to understand its associated theoretical constructs and their predictors. In the second part of my dissertation, I empirically examined the different forms of short-term performance dynamics (mean, maximum, minimum, variability, stability, inertia, week trends, day trends) using two weeks-long experience sampling data from working adults and a) investigated the extent to which they are distinct constructs and whether they have test-retest reliability, and b) tested what situational, time-specific, individual variables are most predictive of each form. I collected ESM data from 237 full-time working participants four times a day for two weeks with a week break in the middle (total observations = 10,315, average response rate = 48.3). I found that there was a high test-retest reliability for specific dynamic features, particularly those of OCB. In addition, I found that there were unique predictors for the same performance domain depending on how their variations were operationalized. </p>

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