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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.
51

Avaliação da correlação da recidiva da sobremordida e da sobressaliência com a recidiva do apinhamento anterior em casos tratados sem extrações / Evaluation of the correlation of the relapse of overbite and overjet with the relapse of anterior crowding in cases treated nonextraction

Renata Cristina Gobbi de Oliveira 28 June 2011 (has links)
O presente estudo retrospectivo objetivou correlacionar a recidiva da sobremordida e da sobressaliência com a recidiva do apinhamento dos incisivos ântero-superiores e ântero-inferiores. A amostra consistiu de 34 pacientes (17 de cada gênero),apresentando más oclusões iniciais de Classe I e II,tratados sem extração e mecânica Edgewise.O tempo médio de duração do tratamento foi de 2,19 anos e os tempos de contenção e pós-contenção foram de 1,46 e 5,31 anos respectivamente. Todos os pacientes apresentavam, pelo menos, 3 mm de sobremordida e 4 mm de sobressaliência e apinhamento superior e inferior, de suave a severo. Foram medidos nos modelos de estudo das fases pré (T1), pós-tratamento (T2) e pós-contenção (T3) a sobremordida, a sobressaliência e o índice de irregularidade de Little superior e inferior. Após a obtenção dos dados, passou-se à análise estatística. A comparação intergrupos foi realizada por meio do teste t independente. Os testes ANOVA e Tukey foram apl icados para verificar se houve recidiva da sobremordida, da sobressaliência e dos apinhamentos ântero-superior e ântero-inferior. Para verificação da presença de correlação entre a recidiva da sobremordida, da sobressaliência e do apinhamento anterior, utilizou-se o teste de correlação de Pearson. Os resultados evidenciaram recidiva estat ist icamente signi ficante para o apinhamento ântero-super ior e ântero- infer ior . Houve correlação entre a recidiva da sobremordida e da sobressaliência, no entanto, não houve relação entre essas duas recidivas e o apinhamento anterior. / The present study aimed to correlate, by means of a retrospective analysis, the postretention stability of the overbite and overjet with the relapse of the crowding of maxillary and mandibular anterior teeth. The sample comprised 34 subjects (17 of each gender), at a mean initial age of 12.89 years, presenting Class I and II malocclusions, treated nonextraction and Edgewise mechanics.All patients presented at least 3mm of overbite and 4mm of overjet and maxillary and mandibular crowding from slight to severe. It was measured, in the dental casts from the stages pretreatment (T1), posttreatment (T2) and postretention (T3), the overbite, overjet and the maxillary and mandibular Little irregularity index. After data were obtained, the statistical analysis was performed. The intergroup comparison was performed by independent t tests. The ANOVA and Tukey tests were applied to verify the relapse of the overbite, overjet and maxillary and mandibular anterior crowding. To verify the presence of correlation among the relapse of the overbite, overjet and the anterior crowding, the Pearsons correlation test was used. Results did not show statistically significant difference between Angles Class I and Class II patients. There was correlation of the relapse of overbite with the relapse of overjet, however, there was no relationship among the relapse of overbite and overjet with the relapse of anterior crowding.
52

Population biology and aspects of the socio-spatial organisation of the woodland dormouse Graphiurus Murinus (Desmaret, 1822) in the Great Fish River Reserve, South Africa

Madikiza, Zimkitha Josephine Kimberly January 2010 (has links)
The population biology and socio-spatial organisation of the woodland dormouse, Graphiurus murinus (Desmarest, 1822), was investigated in a riverine forest at the Great Fish River Reserve (GFRR), South Africa. Data were collected by means of a monthly live trapping and nestbox monitoring programme. Between February 2006 and June 2007, 75 woodland dormice were trapped and/or found in nestboxes and marked: these were 39 adults (13 males, 21 females, five undetermined) and 36 juveniles (five males, 14 females, 17 undetermined). The population showed a steady increase from June 2006–November 2006 and a peak in December 2006–January 2007 as a result of the influx of juveniles. The minimum number of dormice known to be alive (MNA) varied between 40 in December 2006– January 2007 (summer), and a low of three in June 2007 (winter). The range in population density was therefore between 1.2 and 16 dormice per ha. Winter mortality and/or spring dispersal accounted for the disappearance of 55 percent of juveniles. The overall annual adult:juvenile ratio was 1.08. The overall sex ratio was 1.94 female per one male. In females, reproductive activity was observed from September 2006 to end January 2007. The pattern observed in males was similar, as dormice with descended testes were exclusively found from October to end January. Females gave birth during the second half of October to beginning of February. Litters (n = 11) consisted of an average (± SD) 3.73 ± 0.47 young. Over the study period, 27 dormice were trapped or found in nestboxes more than eight times, thus allowing me to estimate their home range size and the spatial overlap between these individuals. On average, dormouse home range size was 2,514 m2 (range: 319 – 4,863 m2). No difference was recorded between one-year old adults and older adults, or between all adults and juveniles. However, adult male dormice (3,989 m2, n = 5) had home ranges almost twice as large as females (2,091 m2, n = 9). No similar trend was found in juveniles. Intrasexual home range overlap was on average 62 percent in adult males, and 26 percent in adult females. However, females overlapped with more neighbouring female home ranges than did males with neighbouring male home ranges, so that, as for males, only small parts of female home ranges were really exclusive. On average, males overlapped a larger Abstract Ecology of woodland dormice M.Sc. Thesis 16 proportion (48 percent) of female home ranges than did females with neighbouring male home ranges (27 percent). In addition, males overlapped with significantly more female home ranges (7.8) than did females with male home ranges (4.9). Trapping success and nestbox data agree with the socio-ecological model. Females showed increased mobility during summer, more likely to find suitable nesting sites, and food for milk production during the reproductive season. The use of nestboxes, however, was constant throughout the year. In males, both the trapping success and nestbox use were higher during the mating season (spring), when an increased mobility and occupation of nestboxes probably increased the chances to locate and mate with (a) receptive female(s). Hence, food and (artificial) nest sites may constitute an important resource for females, whereas females seem to represent the main resource for males. Although food availability was not determined, a comparison of female and male distribution patterns provided interesting information on the mating system of woodland dormice. In GFRR, the dispersion pattern of female woodland dormice was “rather” clumped, i.e. females were non-territorial. As some females showed a dyadic intrasexual overlap of up to 90 percent, and population density was very high at the study site, this may indicate that food was very abundant and/or renewed rapidly. Based on the wide range of birth dates observed during the study period, females clearly come into oestrus at different times. In such circumstances (asynchronous sexual receptivity in females), the Female in Space and Time Hypothesis (Ims 1987a) predicts that males will be non-territorial and promiscuous. Live-trapping, nestbox use and home range data indeed suggested that male woodland dormice do not defend territories, but search for and aggregate around receptive females during the mating season.
53

A quantitative investigation of the experience of household crowding in South African hostels : the case of Kwesine hostel

Payze, Catherine January 2003 (has links)
Submitted in partial fulfilment of the requirements for the Degree of Master of Arts (Clinical Psychology) at the University of Zululand, 2003. / The problems associated with the relationship between humans and their environment are especially marked within the remains of a political system enforced on millions in South Africa. One of the complications of the Apartheid regime was the practice of migrant labour. Migrant labour in itself led to other complications such as disrupted family life, the disintegration of existing social structures and crowding in low-cost housing compounds, commonly known as hostels. It is obvious that the removal of Apartheid from the Statute Books has not resolved the practical problems stemming from its practice. South African hostels are generally characterised by high levels of both social and spatial density. Research (for example Oliver-Evans, 1992; Payze & Keith, 1993; Ramphele, 1993) indicates that several people often share the same bed in one hostel, while a minimum of four beds are usually found in a room of about 3m x 3m. This is usually accompanied by an insufficient infrastructure resulting in for example 16 families sharing one toilet. Other factors also seem to exacerbate the subjective experience of crowding, such as the lack of privacy which frequently accompanies inadequate infrastructure, and a lack of services such as garbage removal, sewerage maintenance, and water and electricity supply. The above research illustrates several discrepancies between the needs of hostel residents and the realities of their physical environment. Within this context the current study qualitatively investigates the subjective experience of household crowding at Kwesine Hostel on the Reef.
54

Överbeläggning på akutmottagningen — åverkan på patientsäkerheten : en litteraturstudie / Crowding at the emergency department : Consequenses for patient safety

Behrbohm, Christian, Borén, Ida January 2023 (has links)
Akutmottagningens uppgift är att omhänderta den akut sjuka patienten, stabilisera, behandla och erbjuda en patientsäker vård av god kvalitet vid oförutsägbara och akuta händelser. Sedan längre tid ses en global trend med ett ökande inflöde till akutmottagningarna, även i Sverige. Detta belastar i allt högre grad en redan pressad organisation och orsakar överbeläggning (“Crowding”), en situation där patientflödet på akutmottagningen överstiger kapaciteten som verksamheten är dimensionerad för. Inte bara inflöde påverkar, utan även vårdtyngd och möjlighet att förflytta patienternavidare i vårdkedjan. Crowding kan leda till försämrat patientflöde, längre vänte- och vårdtider på akutmottagningen, högre arbetsbelastning för personalen och negativa konsekvenser för patienterna. Syftet med detta examensarbete var att belysa hur crowding på akutmottagningen kan påverka patientsäkerheten. För att besvara syftet gjordes en systematisk, integrativ litteraturstudie inkluderande 18 vetenskapliga studier publicerade mellan 2013-2022. Inkluderade studier hämtades från databaserna PubMed, CINAHL och Scopus och kvalitetsgranskades enligt granskningsmallar från Joanna Briggs Institute. En tematisk analys genomfördes, där tre huvudteman identifierades: “Organisatoriska brister”, “Upplevelser av crowding” samt “Vårdskador orsakade av crowding”. Resultatet påvisade att crowding har negativ påverkan på patientsäkerheten, med ökning av både mortalitet och morbiditet. Det tycks däremot inte vara någon proportionell samstämmighet, utan andra faktorer tycks påverka i hög grad. Crowding och otillräckliga resurser medför ett ökat lidande för patienter, anhöriga och personal. Slutsatsen är att crowding på akutmottagningen är ett komplext problem som påverkar hela sjukvården. Med växande och åldrande befolkning kommer problemet troligen fortsätta öka och åtgärder i hela vårdkedjan blir nödvändiga för att inte äventyra patientsäkerheten.
55

Public Issues or Private Concerns: Assessing the Impact of Charitable Choice on Private Donations to Faith-based Organizations

Colon-Mollfulleda, Wanda I. 12 May 2008 (has links)
No description available.
56

The Effects of a Cytoskeletal Drug Swinholide A on Actin Filament Dissembly in a Crowded Environment

Um, Tevin 01 January 2020 (has links)
Actin cytoskeleton reorganization plays essential roles in many cellular processes such as cell structure maintenance, cell motility, and force generation. Cytoskeletal drugs are small molecules that act on cytoskeletal components by either stabilizing or destabilizing them. Swinholide A is an actin-binding drug derived from the marine sponge. Swinholide A binds actin dimers as well as severs filaments. The main objective of this project is to determine how Swinholide A modulates actin filament assembly dynamics in the presence of macromolecular crowding. We utilize total internal reflection fluorescence (TIRF) microscopy imaging to directly visualize Swinholide A-mediated actin filament disassembly and severing. Filament disassembly and severing are evaluated by calculating actin filament lengths and length distribution controlled by Swinholide A. This study helps us better understand the fundamental mechanism by which Swinholide A affects actin assembly and disassembly dynamics. Further studies will allow for investigating new methods of treatment for a range of different diseases that have pathogenetically high levels of filamentous actin, such as cystic fibrosis, as well as a drug to combat the explosive expansion of cancers.
57

The effect of aging on crowded letter recognition in the peripheral visual field

Astle, A.T., Blighe, Alan J., Webb, B.S., McGraw, Paul V. 08 1900 (has links)
Yes / Purpose.: Crowding describes the increased difficulty in identifying a target object when it is surrounded by nearby objects (flankers). A recent study investigated the effect of age on visual crowding and found equivocal results: Although crowded visual acuity was worse in older participants, crowding expressed as a ratio did not change with age. However, the spatial extent of crowding is a better index of crowding effects and remains unknown. In the present study, we used established psychophysical methods to characterize the effect of age on visual crowding (magnitude and extent) in a letter recognition task. Methods.: Letter recognition thresholds were determined for three different flanker separations in 54 adults (aged 18–76 years) with normal vision. Additionally, the spatial extent of crowding was established by measuring spacing thresholds: the flanker-to-target separation required to produce a given reduction in performance. Uncrowded visual acuity, crowded visual acuity, and spacing thresholds were expressed as a function of age, avoiding arbitrary categorization of young and old participants. Results.: Our results showed that uncrowded and crowded visual acuities do not change significantly as a function of age. Furthermore, spacing thresholds did not change with age and approximated Bouma's law (half eccentricity). Conclusions.: These data show that crowding in adults is unaffected by senescence and provide additional evidence for distinct neural mechanisms mediating surround suppression and visual crowding, since the former shows a significant age effect. Finally, our data suggest that the well-documented age-related decline in peripheral reading ability is not due to age-related changes in visual crowding. / Supported by an Age UK Scholarship (AJB); a National Institute of Health Research (NIHR) Postdoctoral Fellowship (ATA); and a Wellcome Trust Career Development Fellowship (BSW).
58

Willingness to Pay for Alternative Programs to Improve Water Quality in the Chesapeake Bay

Harris, Anna Maynard 02 September 2009 (has links)
Over the last century the Chesapeake Bay has been plagued by pollution, disease and overharvesting of its resources. As a result, the Bay has been the focus of substantial research and the beneficiary of numerous environmental programs. Previous work has suggested that people are willing to pay for improved water quality in the Chesapeake Bay. For policymakers, the key challenge is to determine how to allocate scarce funds across alternative regulatory and subsidy programs. This thesis investigates three new research questions that relate to the policymaker's problem. First, does WTP for a given water quality improvement depend on the process used to obtain that improvement? Second, does introducing a publicly funded program to improve water quality crowd out private donations to charitable organizations? Third, could oysters in the Chesapeake Bay be successfully marketed as a "green" good? The results from an attribute based choice experiment survey indicate that individuals value process and that they have a higher value for water quality improvement processes that include positive externalities such as increasing oyster populations and planting acres of tall grasses. The results also imply that the new water quality program will crowd out a small portion of private donations to charitable organizations. For example, a $1 tax increase for a new water quality program would crowd out approximately $0.02 of private donations to Chesapeake Bay organizations. Finally, results from a contingent valuation exercise suggest that oyster consumers are willing to pay a significant premium for ecolabeled oysters. Specifically, consumers are willing to pay a 58% premium for half-shell oysters. / Master of Science
59

Large crowding zones in peripheral vision for briefly presented stimuli

Tripathy, Srimant P., Cavanagh, P., Bedell, H.E. 12 1900 (has links)
Yes / When a target is flanked by distractors, it becomes more difficult to identify. In the periphery, this crowding effect extends over a wide range of target-flanker separations, called the spatial extent of interaction (EoI). A recent study showed that the EoI dramatically increases in size for short presentation durations (Chung & Mansfield, 2009). Here we investigate this duration-EoI relation in greater detail and show that (a) it holds even when visibility of the unflanked target is equated for different durations, (b) the function saturates for durations shorter than 30 to 80 ms, and (c) the largest EoIs represent a critical spacing greater than 50% of eccentricity. We also investigated the effect of same or different polarity for targets and flankers across different presentation durations. We found that EoIs for target and flankers having opposite polarity (one white, the other black) show the same temporal pattern as for same polarity stimuli, but are smaller at all durations by 29% to 44%. The observed saturation of the EoI for shortduration stimuli suggests that crowding follows the locus of temporal integration. Overall, the results constrain theories that map crowding zones to fixed spatial extents or to lateral connections of fixed length in the cortex. / This study was supported by the ERC POSITION 324070 (PC) and a visiting professorship to Anglia Ruskin University from the Leverhulme Trust (HEB).
60

Processus de diffusion et réaction dans des milieux complexes et encombrés / Diffusion-reaction processes in complex and crowded environments

Galanti, Marta 12 February 2016 (has links)
L'objectif général de cette thèse est d'analyser les processus de diffusion et les processus de réaction-diffusion dans plusieurs types de conditions non-idéales, et d'identifier dans quelle mesure ces conditions non idéales influencent la mobilité des particules et les réactions entre les molécules. Dans la première partie de la thèse, nous nous concentrons sur les effets de l'encombrement macromoléculaire sur la mobilité, ainsi élaborant une description des processus de diffusion dans des milieux densément peuplés. Tous les processus sont analysés à partir de la description microscopique du mouvement des agents individuels sous forme de marche aléatoire, tenant compte de l'espace occupé par les particules voisines. La deuxième partie de la thèse vise à caractériser le rôle de la géométrie de l'environnement et de la réactivité des corps qui y sont contenus sur la réaction entre des molécules sélectionnées. La théorie classique de Smoluchowski, formulée pour les réactions contrôlées par la diffusion dans un milieu dilué, est ainsi adaptée à des domaines arbitrairement décorés par des obstacles, dont certains réactifs, et l'équation stationnaire de diffusion est résolue avec des techniques d’analyse harmonique. Finalement, le calcul explicit de la constante de réaction et la dérivation des formules approximées sont utilisés pour étudier des applications biologiques et nano-technologiques. / The overall purpose of this thesis is to analyze diffusion processes and diffusion-reaction processes in different types of non-ideal conditions, and to identify to which extent these non-ideal conditions influence the mobility of particles and the rate of the reactions occurring between molecules. In the first part of the thesis we concentrate on the effects of macromolecular crowding on the mobility of the agents, providing therefore a description of various diffusion processes in densely populated media. All the processes are analyzed by modeling the dynamics of the single agents as microscopic stochastic processes that keep track of the macromolecular crowding. The second part of the thesis aims at characterizing the role of the environment’s geometry (obstacles, compartmentalization) and distributed reactivity (competitive reactants, traps) on the reaction between selected molecules. The Smoluchowski theory for diffusion influenced reactions is thus adapted to domains arbitrarily decorated with obstacles and reactive boundaries, and the stationary diffusion equation is explicitly solved through harmonic-based techniques. The explicit calculation of the reaction rate constant and the derivation of simple approximated formulas are used for investigating nano-technological applications and naturally occurring reactions.

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