1,588 research outputs found
Agricultural Market Structure, Generic Advertising, and Welfare
This analysis begins with a definition and discussion of productive advertising. Then, following Dixit and Norman, persuasive advertising is used to study the welfare effects of generic advertising by marketing orders. The study first examines horizontal competition when the competing advertiser is a monopoly, and results show that the socially optimal level of advertising for a competitive marketing order is positive only if advertising raises monopoly output. Next, advertising choices of a marketing order which sells its output to a monopolistic distributor are considered. If the distributor is a monopolist, then marketing order advertising raises welfare. This finding is in marked contrast to the results for the horizontal case studied by Dixit and Norman.advertising, market structure, welfare, Marketing,
Resultados preliminares do projeto zoneamento do déficit hídrico do TSA utilizando técnicas de teledetecção espacial.
Definição do problema; Apresentação do organograma de trabalho a ser realizado; Dados tratados; Constituição do arquivo bruto.bitstream/item/143278/1/ID-31857.pdfNão publicado
Neighborhood perceptions moderate the association between the family environment and children\u27s objectively assessed physical activity
This study aimed to investigate whether parents\u27 perceptions of the neighborhood environment moderate associations between the family environment and children\u27s moderate- to vigorous-intensity physical activity (MVPA) outside of school hours. In total, 929 parents of 10-12 year-old children completed a questionnaire concerning the family environment, MVPA levels, and the neighborhood environment. Children wore an Actigraph (AM7164-2.2C) accelerometer. Compared with neighborhood environment factors, the family environment was more frequently associated with children\u27s MVPA. Parental MVPA was positively associated with children\u27s MVPA, but only among children whose parents reported a high presence of sporting venues. Having more restrictive physical activity rules was negatively associated with children\u27s weekday MVPA in neighborhoods with high perceived stranger danger
Introduction to a Biological Systems Science
Biological systems analysis and biodynamic modelling of physiological and biological interrelationships in human body and mammal
Objectively measured physical environmental neighbourhood factors are not associated with accelerometer-determined total sedentary time in adults
Background: The physical neighbourhood environment may influence adults' sedentary behaviour. Yet, most studies examining the association between the physical neighbourhood environment and sedentary behaviour rely on self-reported data of either the physical neighbourhood environment and/or sedentary behaviour. The aim of this study was to investigate the associations between objectively measured physical environmental neighbourhood factors and accelerometer-determined total sedentary time in adults.
Methods: In total, 219 Dutch and 128 Belgian adults (mean age +/- SD: 55.8 +/- 15.4 years) were recruited between March and August 2014 as part of the European SPOTLIGHT project. Physical environmental neighbourhood factors, grouped into eight domains, i.e. walking, cycling, public transport, aesthetics, land use mix, grocery stores, food outlets and recreational facilities, were assessed using the SPOTLIGHT Virtual Audit Tool. Sedentary time was collected using ActiGraph GT3X+ accelerometers. General linear mixed models were conducted to examine associations between physical environmental neighbourhood factors and total sedentary time.
Results: Participants were sedentary, on average, for 542.9 min/day (SD: 84.3), or 9.1 h/day. None of the examined physical environmental neighbourhood factors were significantly related to total sedentary time.
Conclusions: Our findings do not support associations of objectively measured physical environmental neighbourhood factors with adults' objectively sedentary time in Dutch and Belgian adults. More research on sedentary behaviours in settings such as the home and work setting is needed to examine the influence of more specific physical environmental factors on these context-specific sedentary behaviours
Effect of cyclosporine on hepatic cytosolic estrogen and androgen receptor levels before and after partial hepatectomy
Estrogen and androgen receptors within the liver have been reported to modulate the hepatic regenerative response to partial hepatectomy. Moreover, cyclosporine has several untoward effects that might occur as a consequence of alterations in sex hormone activity. To evaluate these questions the following experiments were performed. Estrogen and androgen receptors in cytosol were quantitated in livers of rats treated with cyclosporine or olive oil vehicle before and after partial hepatectomy or a sham operation. Ornithine decarboxylase activity and thymidine kinase activity were assessed as indices of hepatic regeneration. Preoperative levels of estrogen receptor activity in the hepatic cytosol were significantly greater in rats treated with cyclosporine as compared to vehicle treated controls (P<0.01). In contrast, preoperative levels of androgen receptor activity in the cyclosporine-treated and vehicle-treated animals were similar. Following partial hepatectomy, a reduction in the activity of both sex hormone receptors in the hepatic cytosol was observed and was compatible with results described previously in normal animals. Unexpectedly the preoperative levels of ornithine decarboxylase (P<0.01) and thymidine kinase activity (P<0.01) were significantly greater in the rats treated with cyclosporine as compared to the vehicle treated controls. As expected, ornithine decarboxylase activity (at 6 hr) and thymidine kinase activity (at 24 hr) rose and peaked in response to a partial hepatectomy but were significantly greater (P<0.05) in the rats treated with cyclosporine as compared to the vehicle. These results show that cyclosporine treatment causes an increase in the hepatic content of estrogen receptor activity that is associated with an enhanced potential for a regenerative response. These effects of cyclosporine treatment on the sex hormone receptor levels in liver may explain the mechanisms responsible for some of the untoward effects of treatment with this agent. © 1990 Plenum Publishing Corporation
Social Interactions vs Revisions, What is important for Promotion in Wikipedia?
In epistemic community, people are said to be selected on their knowledge
contribution to the project (articles, codes, etc.) However, the socialization
process is an important factor for inclusion, sustainability as a contributor,
and promotion. Finally, what does matter to be promoted? being a good
contributor? being a good animator? knowing the boss? We explore this question
looking at the process of election for administrator in the English Wikipedia
community. We modeled the candidates according to their revisions and/or social
attributes. These attributes are used to construct a predictive model of
promotion success, based on the candidates's past behavior, computed thanks to
a random forest algorithm.
Our model combining knowledge contribution variables and social networking
variables successfully explain 78% of the results which is better than the
former models. It also helps to refine the criterion for election. If the
number of knowledge contributions is the most important element, social
interactions come close second to explain the election. But being connected
with the future peers (the admins) can make the difference between success and
failure, making this epistemic community a very social community too
Perceived environmental factors related to adults’ leisure-time physical activity : findings from Europe, Australia and the USA
This journal suppl. entitled: Be Avtive 2012Session 204B - Environments and physical activity: Adults: paper no. 524INTRODUCTION: A growing body of evidence shows that objective and perceived built environment factors are positively associated with physical activity in adults. However, built environment correlates are behavior-specific and the factors associated with leisure-time physical activity are less understood than those associated with active transportation. Furthermore, most previous studies of associations of built environment attributes with physical activity have been conducted in single countries. Limited within-country variability in environmental attributes and physical activity levels can potentially contribute to an underestimation of the strength of the associations. Therefore, the purpose of this study was to examine the strength, direction and shape of the associations of neighborhood environmental perceptions with recreational walking and leisure-time moderate-to-vigorous physical activity, using pooled data from four study sites (Baltimore [USA], Seattle [USA], Adelaide [Australia] and Ghent [Belgium]) in culturally- and environmentally-diverse countries. Moreover, site- and gender-specificity of the associations were examined. METHODS: Data from the four study sites were pooled. In total, 6,014 adults (20–65 years, 55.7% women) were randomly recruited in high-/low-walkable and high-/low-income neighborhoods in the four sites. All participants completed the Neighborhood Environmental Walkability Scale (environmental perceptions) and the International Physical Activity Questionnaire. General additive mixed models were used to estimate the strength and shape of the associations between environmental perceptions and leisure-time activity (walking and moderate-to-vigorous physical activity). RESULTS: Perceived residential density, aesthetics and reporting few barriers to physical activity in the neighborhood were included in a ‘recreational walking-friendliness’ index. This index was linearly positively related to recreational walking in all study sites except Ghent. No gender-differences were observed. The ‘leisure-time activity friendliness’ index consisted of perceived residential density, proximity to recreation facilities, aesthetics and perceiving few barriers in the neighborhood. This index had a positive linear association with leisure-time moderate-to-vigorous physical activity that was significant in all sites but Ghent. Again, no gender-differences in the associations were found. DISCUSSION: Similar environmental attributes were related to both outcome measures in men and women, but the present findings were clearly site-specific, imposing possible challenges for built environment recommendations. In Europe, interventions to promote leisure-time activity may need to target promotion of existing opportunities rather than built environment improvements. In the USA and Australia, a focus on the factors identified in this study, may be of most relevance for promoting leisure-time physical activity
Genetic Covariance Structure of Reading, Intelligence and Memory in Children
This study investigates the genetic relationship among reading performance, IQ, verbal and visuospatial working memory (WM) and short-term memory (STM) in a sample of 112, 9-year-old twin pairs and their older siblings. The relationship between reading performance and the other traits was explained by a common genetic factor for reading performance, IQ, WM and STM and a genetic factor that only influenced reading performance and verbal memory. Genetic variation explained 83% of the variation in reading performance; most of this genetic variance was explained by variation in IQ and memory performance. We hypothesize, based on these results, that children with reading problems possibly can be divided into three groups: (1) children low in IQ and with reading problems; (2) children with average IQ but a STM deficit and with reading problems; (3) children with low IQ and STM deficits; this group may experience more reading problems than the other two
Physical activity to improve cognition in older adults: can physical activity programs enriched with cognitive challenges enhance the effects? A systematic review and meta-analysis
: EPHPP quality rating scores (DOCX 38 kb
- …
