834 resultados para Age factors in disease.
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Most proteins that activate RNA polymerase II-mediated transcription in eukaryotic cells contain sequence-specific DNA-binding domains and "activation" regions. The latter bind general transcription factors and/or coactivators and are required for high-level transcription. Their function in vivo is unknown. Since several activation domains bind the TATA-binding protein (TBP), TBP-associated factors, or other general factors in vitro, one role of the activation domain may be to facilitate promoter occupancy by supporting cooperative binding of the activator and general transcription factors. Using the GAL4 system of yeast, we have tested this model in vivo. It is demonstrated that the presence of a TATA box (the TBP binding site) facilitates binding of GAL4 protein to low- and moderate-affinity sites and that the activation domain modulates these effects. These results support the cooperative binding model for activation domain function in vivo.
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Early neurogenesis progresses by an initial massive proliferation of neuroepithelial cells followed by a sequential differentiation of the various mature neural cell types. The regulation of these processes by growth factors is poorly understood. We intend to understand, in a well-defined biological system, the embryonic chicken retina, the role of the insulin-related growth factors in neurogenesis. We demonstrate the local presence of signaling elements together with a biological response to the factors. Neuroretina at days 6-8 of embryonic development (E6-E8) expressed proinsulin/insulin and insulin-like growth factor I (IGF-I) mRNAs as well as insulin receptor and IGF type I receptor mRNAs. In parallel with this in vivo gene expression, E5 cultured neuroretinas synthesized and released to the medium a metabolically radiolabeled immunoprecipitable insulin-related peptide. Furthermore, insulin-related immunoreactive material with a HPLC mobility close to that of proinsulin was found in the E6-E8 vitreous humor. Exogenous chicken IGF-I, human insulin, and human proinsulin added to E6 cultured neuroretinas showed relatively close potencies stimulating proliferation, as determined by [methyl-3H]thymidine incorporation, with a plateau reached at 10(-8) M. These factors also stimulated neuronal differentiation, indicated by the expression of the neuron-specific antigen G4. Thus, insulin-related growth factors, interestingly including proinsulin, are present in the developing chicken retina and appear to play an autocrine/paracrine stimulatory role in the progression of neurogenesis.
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This paper presents evidence from a psychosocial framework about the relationship among youth, work, and identity construction. The aims of this research were twofold. The first one was to analyze the working conditions of Spanish youth and their impact on individuals' biographies. The second one was to examine the effect of labor-related variables on construction / change of identity elements in Spanish youth. For this purpose, two research techniques were used: the Delphi method (103 experts sample from several entities and organizations closely related to our topic) and deep interviews (15 interviews with youths classified according to their relationship with the work market). Copyright 2007 by The Spanish Journal of Psychology.
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Business organization executives today are routinely challenged to attract and retain key talent and employ innovative techniques to expand their consumer-base. Moreover, these executives have advanced their business initiatives to include workplace equality initiatives with a motivation to attract and retain key talent. In this research the author examined the contributing factors that lead executives in corporate America to implement Gay, Lesbian, Bisexual, and Transgender (GLBT) initiatives as business strategies. The case study methodology applied in this examination illustrated that the implementation of GLBT initiatives can increase a business organization's ability to attract and retain key talent, and increase employee work productivity while expanding the consumer base. Therefore, the business organization's competitive advantage in the marketplace is increased.
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Background: Intimate partner violence (IPV) against women occurs in all countries, all cultures and at every level of society; however, some populations may be at greater risk than others. The aim of this study was to explore IPV prevalence among Ecuadorian, Moroccan and Romanian immigrant women living in Spain and its possible association with their personal, family, social support and immigration status characteristics. Methods: Cross-sectional study of 1607 adult immigrant women residing in Barcelona, Madrid and Valencia (2011). Prevalence rates and adjusted odds ratios (AORs) were calculated, with current IPV being the outcome. Different women’s personal (demographic), family, social support and immigration status characteristics were considered as explicative and control variables. All analyses were separated by women’s country of origin. Results: Current IPV prevalence was 15.57% in Ecuadorians, 10.91% in Moroccans and 8.58% in Romanians. Some common IPV factors were found, such as being separated and/or divorced. In Romanians, IPV was also associated with lack of social support [AOR 5.96 (1.39–25.62)] and low religious involvement [AOR 2.17 (1.06–4.43)]. The likelihood of current IPV was lower among women without children or other dependants in this subgroup [AOR 0.29 (0.093–0.92)]. Conclusion: The IPV prevalence rates obtained for Moroccan, Romanian and Ecuadorian women residing in Spain were similar. Whereas the likelihood of IPV appeared to be relatively evenly distributed among Moroccan and Ecuadorian women, it was higher among Romanian women in socially vulnerable situations related to family responsibilities and the lack of support networks. The importance of intervention in the process of separation and divorce was common to all women.
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Team handball is an Olympic sport played professionally in many European countries. Nevertheless, a scientific knowledge regarding women's elite team handball demands is limited. Thus, the purpose of this article was to review a series of studies (n = 33) on physical characteristics, physiological attributes, physical attributes, throwing velocity, and on-court performances of women's team handball players. Such empirical and practical information is essential to design and implement successful short-term and long-term training programs for women's team handball players. Our review revealed that (a) players that have a higher skill level are taller and have a higher fat-free mass; (b) players who are more aerobically resistant are at an advantage in international level women team handball; (c) strength and power exercises should be emphasized in conditioning programs, because they are associated with both sprint performance and throwing velocity; (d) speed drills should also be implemented in conditioning programs but after a decrease in physical training volume; (e) a time-motion analysis is an effective method of quantifying the demands of team handball and provides a conceptual framework for the specific physical preparation of players. According to our results, there are only few studies on on-court performance and time-motion analysis for women's team handball players, especially concerning acceleration profiles. More studies are needed to examine the effectiveness of different training programs of women's team handball players' physiological and physical attributes.
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In order to evaluate taxonomic and environmental control on the preservation pattern of brachiopod accumulations, sedimentologic and taphonomic data have been integrated with those inferred from the structure of brachiopod accumulations from the easternmost Lower Jurassic Subbetic deposits in Spain. Two brachiopod communities (Praesphaeroidothyris and Securina communities) were distinguished showing a mainly free-lying way of life in soft-bottom habitats. Three taphofacies are discriminated based on proportion of disarticulation, fragmentation, packing, and shell filling. Taphofacies 1 is represented by thinly fragmented, dispersed brachiopod shells in wackestone beds. Taphofacies 2 is spatially restricted to small lenses where shells are poorly fragmented, rarely disarticulated, usually void filled, and highly packed. Taphofacies 3 is represented by mud or cement filled, loosely packed, articulated brachiopods forming large pocket-like structures. Temporal and spatial averaging were minimally involved in taphofacies 2 and 3. It is interpreted that patchy preservation implies preservation of primary original patchiness of brachiopod communities on the seafloor. The origin of shell-rich taphofacies (2 and 3) is related to rapid burial due to episodic storm activity, while shell-poor taphofacies 1 records background conditions. The nature and comparative diversity of these taphofacies underscores the importance of rapid burial for shell beds preservation. Differences in preservation between taphofacies 2 and 3 are mainly related to environmental criteria, most importantly storm energy and water depth. In contrast, the taxonomic-specific pattern of the communities is a subordinate element of control, controlling only minor within-taphofacies differences in preservation.
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Because millions of youth are involved in sport, the sport context is important to consider in advancing the growth experiences of young people (Cˆot´e et al., 2007; Fraser-Thomas et al., 2005). Furthermore, research in developmental psychology has highlighted the value of structured programs, including sport, in helping to promote positive youth development (Fredricks & Eccles, 2006). Youth sport involvement has been linked to high levels of enjoyment (Scanlan et al., 1989), however, negative outcomes, such as burnout, have also been reported (Gould et al., 1996). In the present study, the Developmental Assets Profile (Search Institute, 2004) was used to explore personal (internal assets) and contextual (external assets) outcomes associated with youth sport. Results suggest that three particular assets (positive identity, empowerment, and support) are important to focus on in youth sport programs to decrease burnout symptoms and enhance enjoyment. Path analyses were also conducted to test a proposed model and exploratory results confirmed links of particular assets to sport outcomes. The results are discussed in terms of integration with Bronfenbrenner’s ecological theory (1999) and recommendations are suggested for sport programmers to consider to develop these assets within youth sport.
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Mode of access: Internet.
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Federal Highway Administration, Structures and Applied Mechanics Division, Washington, D.C.
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Federal Highway Administration, Structures and Applied Mechanics Division, Washington, D.C.
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Federal Highway Administration, Structures and Applied Mechanics Division, Washington, D.C.