• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 1061
  • 508
  • 180
  • 120
  • 76
  • 75
  • 58
  • 34
  • 28
  • 19
  • 18
  • 17
  • 15
  • 9
  • 9
  • Tagged with
  • 2599
  • 568
  • 472
  • 457
  • 418
  • 412
  • 305
  • 280
  • 280
  • 224
  • 211
  • 206
  • 193
  • 180
  • 174
  • 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.
241

Bi-directional flow in the Social Force Model

Johansson, Anton January 2016 (has links)
We use the social force model to study the behaviour of two crowds of pedestrians in a bi-directional flow. There are two main goals of the project. The first goal is to study the effects of perception anisotropy on lane formation of the two crowds. The perception anisotropy models the fact that people actually do not perceive their surroundings equally well in all directions, i.e they have a field of vision. The second goal is to develop pedestrian viscosity indices to characterize the motion of the crowds. Our concepts of viscosity indices estimate how fluid the motion of the crowds are. We develop two viscosity indices. A lane viscosity index which gives information of the flow on large timescales, and a space-dependent viscosity index which can pinpoint where in space the motion is less fluid. Our results indicate that there is a small correlation between the perception anisotropy and the lane formation of the two crowds. The two viscosity indices work as intended but more refinement is needed to cope with simultaneous space-time changes.
242

似藝術-art-like : problems and contradictions in developing an artistic research

Lee, James Ming-Hsueh January 2013 (has links)
The main purpose of this research is to examine artistic thinking processes from my practical experience as an artist. This thinking process is discussed through my term: 似藝術-art-like in the context of 'practice-based research'. '似藝術-art-like' is an amalgamated form of Mandarin characters with English words; it is both a picture and a word that serves as a temporary conceptual framework that aims to keep possibility open and meaning mobile.' Significantly,似藝術-art-like is addressed through language and artworks together with an attempt to reinterpret the relation between thinking, outcomes of thinking, and the complexity of meaning in relation to art. 似藝術-art-like operates as a temporary conceptual framework for discussing the thinking process and demonstrating the problems and contradictions in art research. This is a practice-based study so that visual and written elements and the structure of the thesis are each approached as a form of 'practice'. In addressing 似藝術-art-like in the written elements of the thesis, a series of stratagems or gambits are employed that attempt to explain or find formulation for the developing thinking process in art research. Each gambit is a form of artifice that serves to demonstrate the pursuit of addressing thinking through language as an impossible task, and functions as a manoeuvre for opening a conversation in understanding the thinking process in art. To facilitate my understanding, I explore my questioning of thinking in relation to Jacques Derrida's supplement and différance, Gilles Deleuze and Félix Guattari's rhizome, Mieke Bal's, framing, Susanne Langer's distinction between art and language, and Immanuel Kant's disinterestedness and aesthetic idea. It becomes apparent that no one theory satisfactorily explains what happens; it is too complex. Presentation of the inadequateness and contradictions in my developing process provides an examination of there being no specific answer. As a result, I conclude that utilising written words and artworks in my thinking processes and demonstrating them as physical outcomes is a process of constant confrontation with contradictions. It is a provocation that makes an artist-based researcher/research-based artist, re-think, re-disturb, re-articulate, and re-consider the conceptual frameworks in relation to developing artistic research. Ultimately, this research responds to the problems surrounding the relationship between thinking and the outcomes of thinking and meaning in relation to art. It demonstrates the difficulties and complications for seeking mobile thinking and for exploring the possibilities of artistic research. As a whole, the research points out the complexity of the process in terms of employing thinking through artworks and written words together. This invites a suspension of preconceived concepts and questions what knowledge mightbe in the context of an art enquiry.
243

Insulin-like growth factor I and linear growth at birth to five days in rats

Chan, Yue-sin. January 2002 (has links)
published_or_final_version / abstract / Medical Sciences / Master / Master of Medical Sciences
244

Study of the StpA protein from Salmonella typhimurium and Escherichia coli

Sonnenfield, Jean Marie January 1997 (has links)
No description available.
245

The oestrogen receptor in porcine granulosa cells

Bains, Harvinder January 2002 (has links)
No description available.
246

Elucidation of Jasmonate-Responsive Promoter Elements in the Calmodulin-Like Gene CML39 in Arabidopsis

Maj, DAVID 27 September 2013 (has links)
All organisms require rapid and flexible signaling mechanisms in order to effectively respond to biotic and abiotic stress. Calcium ions (Ca2+) have proven to be important components of signaling networks. Observations of stimulus-specific oscillations of cytosolic Ca2+ during signal transduction suggest that Ca2+ signals directly encode information. These stimulus-specific oscillations, known as Ca2+ signatures, can be interpreted by an array of Ca2+-binding sensors and effectors, which subsequently regulate appropriate cellular responses. While progress has been made regarding the classic Ca2+-sensor calmodulin (CaM), less research has been directed towards the CaM-like family of Ca2+-sensors (CMLs). This family – unique to plants – is suspected to regulate a multitude of stress and developmental pathways; however, to date very few members of this family have had their functions elucidated by the identification of downstream targets and upstream regulators. In the present study, I investigate the regulation of CML39, which has previously been shown to strongly respond to the stress hormone jasmonic acid (JA) in Arabidopsis. Bioinformatic tools predict a large number of putative JA-responsive cis-elements within the CML39 promoter. Deletion analysis of CML39 promoter fragments in planta reveals that some cis-elements respond in a tissue-specific manner. Analysis of transgenic MYC2 loss-of-function (myc2) mutants demonstrates that MYC2 – the preeminent JA-responsive transcription factor – is not necessary for CML39 promoter activity. Collectively, these data reveal a complex tissue-specific pattern of CML39 regulation and provide a foundation for the future identification of relevant transcription factors. / Thesis (Master, Biology) -- Queen's University, 2013-09-24 21:06:30.592
247

The influence of a simple shear deformation on a long wave motion in a pre-stressed incompressible elastic layer

Amirova, Svetlana R. January 2008 (has links)
No description available.
248

Exploring individual differences in deductive reasoning as a function of 'autistic'-like traits

Fugard, Andrew J. B. January 2009 (has links)
From a logical viewpoint, people must reason to as well as from interpretations in deductive reasoning tasks. There are two main interpretative stances (e.g., Stenning & van Lambalgen, 2004, 2005, 2008): credulous, the act of trying to infer the speaker's intended model; and sceptical, an adversarial strategy. A range of contextual factors in uence interpretation, but there are also differences between individuals across situations. Taking an individual differences approach, this thesis focuses on reasoning in relation to milder variants of the autism spectrum condition (ASC) phenotype in a typically developing (TD) population. Earlier work on discourse processing in ASC using the `suppression' task (van Lambalgen & Smid, 2004; Pijnacker et al., In press) shows that some aspects of reasoning to interpretations are different in the ASC population. Given that autistic traits involve impairment, e.g., in pragmatic language, and peaks of ability, e.g., in perceptual tasks, it was hypothesised that autistic traits would predict features of the inferences people in the TD population draw. Data were collected from university students on a range of reasoning tasks making it possible to investigate the extent to which interpretation is consistent across task within individuals. Tasks chosen were: conditional reasoning using the `suppression' task and Wason's selection task; one and two-premise Aristotelian quantifer reasoning; the Linda problem; and Raven's Advanced Progressive Matrices. Autistic traits were assessed using the Autism Spectrum Quotient (Baron-Cohen et al., 2001), used previously to study autistic traits in TD individuals, and the Broad Autism Phenotype Questionnaire (Hurley et al., 2007). Autistic traits predicted patterns of inference in many of the tasks. The earlier suppression task result in ASC was replicated and extended in our TD population. Different dimensions of autistic trait related differentially to features of the inferences drawn. Some of the inferences drawn were recognisably related to the credulous versus sceptical distinction and correlated cross-task whilst others were seemingly related to more general topdown versus bottom-up processing preferences. These results provide further evidence of the existence of qualitative individual differences in deductive reasoning. They also show the importance of seeking cross-task correlates to move beyond studies of individual tasks and study reasoning to and from interpretations in the same individual.
249

Nanostructured carbon-based thin films : prediction and design

Goyenola, Cecilia January 2015 (has links)
Carbon-based thin films are a vast group of materials of great technological importance. Thanks to the different bonding options for carbon, a large variety of structures (from amorphous to nanostructured) can be achieved in the process of film synthesis. The structural diversity increases even more if carbon is combined with relatively small quantities of atoms of other elements. This results in a set of materials with many different interesting properties for a wide range of technological applications. This doctoral thesis is about nanostructured carbon-based thin films. In particular, the focus is set on theoretical modeling, prediction of structural features and design of sulfo carbide (CSx) and carbon fluoride (CFx) thin films. The theoretical approach follows the synthetic growth concept (SGC) which is based on the density functional theory. The SGC departure point is the fact that the nanostructured films of interest can be modeled as assemblies of low dimensional units (e.g., finite graphene-like model systems), similarly to modeling graphite as stacks of graphene sheets. Moreover, the SGC includes a description of the groups of atoms that act as building blocks (i.e., precursors) during film deposition, as well as their interaction with the growing film. This thesis consists of two main parts: Prediction: In this work, I show that nanostructured CSx thin films can be expected for sulfur contents up to 20 atomic % with structural characteristics that go from graphite-like to fullerene-like (FL). In the case of CFx thin films, a diversity of structures are predicted depending on the fluorine concentration. Short range ordered structures, such as FL structure, can be expected for low concentrations (up to 5 atomic %). For increasing fluorine concentration, diamond-like and polymeric structures should predominate. As a special case, I also studied the ternary system CSxFy. The calculations show that CSxFy thin films with nanostructured features should be possible to synthesize at low sulfur and fluorine concentrations and the structural characteristics can be described and explained in terms of the binaries CSx and CFx. Design: The carbon-based thin films predicted in this thesis were synthesized by magnetron sputtering. The results from my calculations regarding structure and composition, and analysis of precursors (availability and role during deposition process) were successfully combined with the experimental techniques in the quest of obtaining films with desired structural features and understanding their properties.
250

SEX DIFFERENCES IN MORPHINE ANALGESIA AND THE ROLE OF MICROGLIA IN THE PERIAQUEDUCTAL GRAY OF THE RAT

Doyle, Hillary 08 August 2017 (has links)
Morphine has been and continues to be one of the most potent and widely used drugs for the treatment of pain. Clinical and animal models investigating sex differences in pain and analgesia demonstrate that morphine is a more potent analgesic in males than in females; indeed, we report the effective dose of morphine for female rats is twice that of male rats. In addition to binding to the neuronal mu opioid receptor, morphine binds to the innate immune receptor toll-like receptor 4 (TLR4) on microglia. Morphine action at TLR4 initiates a neuroinflammatory response and directly opposes morphine analgesia. Our recent studies demonstrate that administration of chronic morphine activates microglia within the ventrolateral periaqueductal gray (vlPAG), a critical brain region for the antinociceptive effects of morphine, while blockade of vlPAG microglia increases morphine analgesia and suppresses the development of tolerance in male rats. Despite increasing evidence of the involvement of microglia in altering morphine efficacy, no studies have examined sex differences in microglia within the PAG. The present experiments seek to characterize the distribution and activity of vlPAG microglia in males and females using behavioral, immunohistochemical and molecular techniques, while demonstrating the sufficiency and necessity of vlPAG microglia to produce sex differences in morphine analgesia using site-specific pharmacological manipulation of TLR4. We also investigate a novel pharmacokinetic mechanism underlying the sexually dimorphic effects of morphine administration on microglial activity. Here, we address a fundamental gap in our current understanding of sex differences in morphine analgesia and establish a mechanistic understanding of how the activation of vlPAG microglia sex-specifically influences morphine analgesia.

Page generated in 0.051 seconds