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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.
521

Den ena boplatsvallen är den andra lik? : Miljöarkeologisk intra-site studie av boplatsvallar vid Lillsjön, Anundsjö sn., Ångermanland

Sjölander, Mattias January 2014 (has links)
Boplatsvallar, often translated as semi-subterranean settlements, is an ancient monument with a diffuse definition. Defined as –embankments that partially or completely surround a often lowered/dug down surface- this category of ancient monuments is also made up of a former category which traditionally was interpreted as winter settlements from the late Stone age in Sweden. This view of the ancient monuments carried over, to a certain extent, to this new definition. Should this be the case, that this category of ancient monuments are remains of winter settlements,  used recurringly over an extended period of time, then they should exhibit similar signals in regards to the distribution of the anthropogenically altered soil chemical and soil physical properties at the sites.The area around Lillsjön, Anundsjö parish in Ångermanland, have four boplatsvallar located separately in the regional area. This means that they can be considered single contexts suitable to test the aforementioned hypothesis.The result of the intra-site study indicates that the sites have been used differently. Two of the sites exhibit a more local distribution of the heightened values of phosphates and magnetic susceptibility, distributed close around the ancient monument itself. The other two sites have a distribution of heightened values spread over a larger area around the ancient monuments, where one of the ancient monuments shows no particular difference from the background values at the site.This results thus suggests that there is a difference in how these boplatsvallar have been used prehistorically.
522

School Travel Mode Choice Behaviour in Toronto, Canada

Mitra, Raktim 19 March 2013 (has links)
Interest in school transportation has emerged in response to concern over the reduced levels of physical activity among children and youth. Recent Canadian policies emphasize population health intervention to encourage active travel among this younger population; urban planners and public health professionals have also highlighted the importance of the neighbourhood built environment. However, this “child-youth friendly” turn in policy and planning practice, particularly in Canada, has arguably occurred in advance of conclusive and generalizable knowledge about the relationship between the built environment and children’s travel. Within this context, this thesis is the first quantitative research that examines school transportation mode choice behaviour in the largest Canadian city, the City of Toronto. At first, a Behavioural Model of School Transportation was outlined. This exercise was followed by three empirical studies that explored school travel by children and youth, using travel data from Transportation Tomorrow Survey. The first of these three studies investigated the association between the built environment and the likelihood of walking or being driven, for journeys to and from school. The next study focused on a measurement issue; the potential influence of the modifiable areal unit problem on statistical modelling of the built environment - mode choice relationship was examined. Lastly, the potential influence of travel interactions among household members, the built environment, and unobservable spatial dependency (i.e., spatial auto-correlation), on school travel outcome of children and youth, were examined. The results indicated that caregiver availability may influence travel mode choice. The built environment near both home and school locations was associated with the likelihood of walking. In addition, the correlates of mode choice were different between children and youth, which perhaps, reflects a child’s cognitive development with age as an independent traveller. These findings suggest the need for neighbourhood-wide improvement in the built environment, and age-specific population health interventions at schools and in the communities.
523

An Event-related Potential Investigation on Associative Encoding and the Effects of Intra-list Semantic Similarity

Kim, Alice Sun-Nam 14 July 2009 (has links)
Event-related potentials were recorded as subjects were presented with pairs of words, one word at a time, to examine the electrocortical manifestations of association formation and the effect of intra-list semantic similarity. Two types of lists were presented: Same – all pairs belonged to the same semantic category; Different – all pairs belonged to a different semantic category. Subjects were told to memorize the pairs for a following paired associate recall test. Recall was better for the Different than Same lists. Subsequent recall was predicted by the amplitudes of a potential lasting throughout the epoch and the P555 to each word of a pair (likely reflecting state- and item-related encoding activity, respectively), as well as a late positive wave that occurred after the offset of the second word, which is thought to reflect association formation. A larger N425 was elicited by pairs in the Different than Same lists, likely reflecting semantic integration.
524

Improvement of Cotton Fiber Maturity and Assessment of Intra-Plant Fiber Variability

Kothari, Neha 2012 August 1900 (has links)
The temporal system of fruiting on the cotton plant lends itself to bolls at different fruiting sites developing under different environmental conditions and with varied source-sink relationships. To investigate this, intra-plant fiber quality was assessed in four upland cultivars at College Station, Texas for three years and at Lubbock, Texas for two years. It was concluded that fiber quality steadily declines from the bottom sympodial branches towards the upper branches. 'FiberMax 832' had the best fiber quality among all cultivars but it also had the highest degree of variability within the plants. 'Half and Half' and 'Acala 1517-99' appear to have the least amount of intra-plant variability of fiber quality. Bolls from the bottom region of the plant have higher trash content compared to the upper region. To test the impact of fiber quality variability on boll sampling techniques employed, ten sampling protocols were compared against each other for three years in College Station, Texas, for two upland cultivars. Results suggest that randomized boll samples containing 50 bolls worked well to estimate inherent fiber quality for most fiber traits while estimation of trash and lint percent was not predictable based on boll samples. One of the problems associated with intra-plant fiber variability was the presence of immature fibers. In order to determine the potential for improvement of fiber maturity and standard fineness, five upland cotton (Gossypium hirsutum L.) genotypes were subjected to a diallel analysis at College Station, Texas, in 2011. Four cultivars that tend to produce fine and mature fibers and one cultivar that tends to produce coarse fibers were intermated in all combinations, without reciprocals. Estimates of general (GCA) and specific combining ability (SCA) for fiber maturity ratio and standard fineness based on Griffing's diallel Model I, Method 4 were calculated for AFIS and fiber micronaire, length and strength measurements for High Volume Instrument (HVI). Four parents had significant GCA effects and Acala 1517-99 was found to be the best parent for improving standard fineness followed by FiberMax 832 and 'Tamcot HQ-95'. Tamcot HQ-95 was the best parent to improve fiber maturity ratio while 'Deltapine 90' was the best parent to reduce fiber maturity ratio. The specific cross between Acala 1517-99 and Tamcot HQ-95 had the best performance. Diallel analysis indicated that fiber maturity ratio was influenced by non-additive gene effects more than additive gene effects while fiber standard fineness was highly influenced by additive gene effects. Developing cultivars with optimal fiber standard fineness and maturity should be prioritized to address problems associated with neps and short fiber content and improve spinning performance of US cotton.
525

Family Size and Relative Need

Bradbury, Bruce William, Economics, Australian School of Business, UNSW January 1997 (has links)
This thesis examines three questions concerned with the relative income needs of families of different sizes - often summarised by indices known as ???equivalence scales???. The first is the extent to which researchers and policy makers should offset the costs of family composition (eg the expenditure costs of children) with the benefits associated with demographic choice (eg the ???joys of parenthood???). Chapter 2 concludes that there are demographic and financial market constraints that will often make a narrow focus on expenditure costs appropriate for distributional research and tax/transfer policies. However, this will not always be the case. One implication of this result is that it may be reasonable for distributional research to use different equivalence scales for adults and children in the same household. Part 2 of the thesis introduces a new method for the estimation of the within-household income distribution and expenditure costs of different family types. This is based upon the household welfare model of Samuelson together with Lau???s method for modelling the joint consumption of household goods. In Chapter 4, this method is applied to the estimation of equivalence scales for older singles and married couples. The estimation is based upon a detailed set of assumptions about the extent of joint consumption for 17 different commodity groups. The main conclusions are that: the theoretical model fits the observed behaviour well (with the exception of some home production effects); that aged couples share their income relatively evenly; and that the relative rate of pension for aged singles in Australia is probably too low. In Part 3, the thesis examines how changes in poverty can be estimated when there is uncertainty about the equivalence scale. The thesis proposes a new method which permits a set of upper and lower bounds for the equivalence scale to be assumed, which in turn determine upper and lower bounds for the increase in poverty. This method is applied to measure the change in poverty in Australia during the 1980s. Equivalence scales can be found that imply either an increase or a decrease in poverty.
526

Elucidating the fear - maintaining properties of the Ventral Tegmental Area

Taylor, Amanda Lee January 2008 (has links)
The ventral tegmental area (VTA) and its dopaminergic (DA) mesocorticolimbic projections are thought to be essential in the brain’s reward neurocircuitry. In humans and animal experimental subjects, mild electrical VTA stimulation increases dopamine levels and can induce euphoria. Paradoxically, aversive stimuli activate VTA neurons and forebrain DA activity, and excessive electrical stimulation of the VTA exaggerates fearfulness. Research suggests that experimental manipulation of either the amygdala or the VTA has similar effects on the acquisition and expression of Pavlovian conditioned fear. Recently it was demonstrated that electrical stimulation of the amygdala produced fear extinction deficits in rats. Fear extinction involves the progressive dissipation of conditioned fear responses by repeated non-reinforced exposure to a conditioned stimulus (CS). Maladaptive states of fear in fear-related anxiety disorders, such as post-traumatic stress disorders (PTSD) or specific phobias are thought to reflect fear extinction learning deficits. The primary purpose of the present study was to examine the effects of intra-VTA stimulation on fear extinction learning. Using fear-potentiated startle as a behavioural index of conditioned fear, it was found that 120 VTA stimulations paired or unpaired with non-reinforced CS presentations impaired the extinction of conditioned fear. This effect was not apparent in rats that received electrical stimulation of the substantia nigra (SN), suggesting that not all midbrain regions respond similarly. Electrical stimulation parameters did not have aversive affects because rats failed to show fear conditioning when electrical VTA stimulation was used as the unconditioned stimulus. Also, VTA stimulation did not alter conditioned fear expression in non-extinguished animals. Based on the results it is suggested that VTA activation disinhibited conditioned fear responding. Therefore, VTA neuronal excitation by aversive stimuli may play a role in fear-related anxiety disorders thought to reflect extinction learning deficits.
527

On the importance of fat cell size, location and signaling in insulin resistance /

Franck, Niclas, January 2009 (has links) (PDF)
Diss. (sammanfattning) Linköping : Linköpings universitet, 2009. / Härtill 4 uppsatser.
528

The psychological dynamics of group-based considerations on partisanship a case study of Christian conservatives and conflict in the Republican Party /

McAdams, Erin Stamatia, January 2009 (has links)
Thesis (Ph. D.)--Ohio State University, 2009. / Title from first page of PDF file. Includes vita. Includes bibliographical references (p. 196-207).
529

South Africa-US intra-industry trade in services

Sichei, Moses Muse. January 2005 (has links)
Thesis (Ph.D. (Economics))-University of Pretoria, 2005. / Includes summary. Includes bibliographical references. Available on the Internet via the World Wide Web.
530

Novel chemically selective rapid magnetic resonance imaging techniques and the clinical applications

Peng, Qi. January 2005 (has links)
Thesis (Ph.D.) -- University of Texas Southwestern Medical Center at Dallas, 2005. / Embargoed. Vita. Bibliography: 149-156.

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