981 resultados para H. Stern
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Thesis (doctoral)--
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Mode of access: Internet.
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Mode of access: Internet.
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Mode of access: Internet.
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En las últimas décadas se observa un creciente deterioro del medio ambiente y una intensificación de los fenómenos climáticos asociados al cambio climático. Es posible, desde el ámbito económico, entender a este deterioro ambiental y el problema del cambio climático como la consecuencia lógica de diversas externalidades negativas (Stern, 2007). En este contexto, la polÃtica fiscal es un instrumento fundamental para reducir o eliminar las externalidades negativas asociadas al medio ambiente y al mismo tiempo fomentar el crecimiento económico, el empleo y en general el bienestar de la población. En América Latina existen pocas experiencias, la mayor parte recientes, de uso de la polÃtica fiscal ambiental para enfrentar los problemas ambientales, como la contaminación atmosférica, el cambio climático, entre otros. En este contexto, el objetivo del presente documento es sistematizar las iniciativas ejecutadas por el Gobierno de Ecuador en materia de fiscalidad e iniciativas ambientales, analizando los avances logrados en los últimos años asà como los desafÃos y recomendaciones para avanzar hacia un desarrollo más sustentable.
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There is considerable evidence that environmental variables can substantially influence consumer behavior in service settings (cf. Turley and Milliman, 2000). However, research to date has focused on the effects of the physical elements (‘atmospherics’), with the social aspects (customers and service providers) of the environment largely ignored. First, we provide a review of the extant literature drawing on four major streams of research from (1) previous marketing (servicescapes); (2) environmental psychology (approach–avoidance theory, behavior setting theory); (3) social psychology (social facilitation theory); and (4) organizational behavior (affective events theory). Second, we present a new conceptual model, the ‘Social-servicescape’. In this paper we argue that the social environment and purchase occasion dictates the desired social density which influences customers’ affective and cognitive responses, including repurchase intentions. Furthermore, we argue that customers play a key role in influencing the emotions of others either positively or negatively, and this largely determines whether they intend to return to the service setting. Implications of this conceptual model for theory and practice are discussed.
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The synthesis, structural characterization, and photophysical behavior of a 14-membered tetraazamacrocycle with pendant 4-dimethylaminobenzyl (DMAB) and 9-anthracenylmethyl groups is reported (L-3, 6-((9-anthracenylmethyl)amino)-trans-6,13-dimethyl-13-((4-dimethylaminobenzyl)amino)-1,4,8,11-tetraaza-cyclotetradecane). In its free base form, this compound displays rapid intramolecular photoinduced electron transfer (PET) quenching of the anthracene emission, with both the secondary amines and the DMAB group capable of acting as electron donors. When complexed with Zn(II), the characteristic fluorescence of the anthracene chromophore is restored as the former of these pathways is deactivated by coordination. Importantly, it is shown that the DMAB group, which remains uncoordinated and PET active, acts only very weakly to quench emission, by comparison to the behavior of a model Zn complex lacking the pendant DMAB group, [ZnL2](2+) (Chart 1). By contrast, Stern-Volmer analysis of intermolecular quenching of [ZnL2](2+) by N,N-dimethylaniline (DMA) has shown that this reaction is diffusion limited. Hence, the pivotal role of the bridge in influencing intramolecular PET is highlighted.
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In many instances, kidney dysgenesis results as a secondary consequence to defects in the development of the ureter. Through the use of mouse genetics a number of genes associated with such malformations have been identified, however, the cause of many other abnormalities remain unknown. In order to identify novel genes involved in ureter development we compared gene expression in embryonic day (E) 12.5, E15.5 and postnatal day (P) 75 ureters using the Compugen mouse long oligo microarrays. A total of 248 genes were dynamically upregulated and 208 downregulated between E12.5 and P75. At E12.5, when the mouse ureter is comprised of a simple cuboidal epithelium surrounded by ureteric mesenchyme, genes previously reported to be expressed in the ureteric mesenchyme, foxC1 and foxC2 were upregulated. By E15.5 the epithelial layer develops into urothelium, impermeable to urine, and smooth muscle develops for the peristaltic movement of urine towards the bladder. The development of these two cell types coincided with the upregulation of UPIIIa, RAB27b and PPAR gamma reported to be expressed in the urothelium, and several muscle genes, Acta1, Tnnt2, Myocd, and Tpm2. In situ hybridization identified several novel genes with spatial expression within the smooth muscle, Acta1; ureteric mesenchyme and smooth muscle, Thbs2 and Co15a2; and urothelium, Kcnj8 and Adh1. This study marks the first known report defining global gene expression of the developing mouse ureter and will provide insight into the molecular mechanisms underlying kidney and lower urinary tract malformations. (c) 2005 Elsevier B.V. All rights reserved.
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The Crim1 gene encodes a transmembrane protein containing six cysteine-rich repeats similar to those found in the BMP antagonist, chordin (chd). To investigate its physiological role, zebrafish crim1 was cloned and shown to be both maternally and zygotically expressed during zebrafish development in sites including the vasculature, intermediate cell mass. notochord, and otic vesicle. Bent or hooked tails with U-shaped somites were observed in 85% of morphants from 12 hpf. This was accompanied by a loss of muscle pioneer cells. While morpholino knockdown of crim1 showed some evidence of ventralisation, including expansion of the intermediate cell mass (ICM), reduction in head size bent tails and disruption to the somites and notochord, this did not mimic the classically ventralised phenotype, as assessed by the pattern of expression of the dorsal markers chordin, otx2 and the ventral markers eve1, pax2.1, tall and gata1 between 75% epiboly and six-somites. From 24 hpf, morphants displayed an expansion of the ventral mesoderm-derived ICM, as evidenced by expansion of tall. Imo2 and crim1 itself. Analysis of the crim1 morphant phenotype in Tg(fli:EGFP) fish showed a clear reduction in the endothelial cells forming the intersegmental vessels and a loss of the dorsal longitudinal anastomotic vessel (DLAV). Hence, the primary role of zebrafish crim1 is likely to be the regulation of somitic and vascular development. (c) 2006 Elsevier Ireland Ltd. All rights reserved.
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Spatial gradients in mangrove tree height in barrier islands of Belize are associated with nutrient deficiency and sustained flooding in the absence of a salinity gradient. While nutrient deficiency is likely to affect many parameters, here we show that addition of phosphorus (P) to dwarf mangroves stimulated increases in diameters of xylem vessels, area of conductive xylem tissue and leaf area index (LAI) of the canopy. These changes in structure were consistent with related changes in function, as addition of P also increased hydraulic conductivity (K-s), stomatal conductance and photosynthetic assimilation rates to the same levels measured in taller trees fringing the seaward margin of the mangrove. Increased xylem vessel size and corresponding enhancements in stern hydraulic conductivity in P fertilized dwarf trees came at the cost of enhanced midday loss of hydraulic conductivity and was associated with decreased assimilation rates in the afternoon. Analysis of trait plasticity identifies hydraulic properties of trees as more plastic than those of leaf structural and physiological characteristics, implying that hydraulic properties are key in controlling growth in mangroves. Alleviation of P deficiency, which released trees from hydraulic limitations, reduced the structural and functional distinctions between dwarf and taller fringing tree forms of Rhizophora mangle.
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The E11.5 mouse metanephros is comprised of a T-stage ureteric epithelial tubule sub-divided into tip and trunk cells surrounded by metanephric mesenchyme (MM). Tip cells are induced to undergo branching morphogenesis by the MM. In contrast, signals within the mesenchyme surrounding the trunk prevent ectopic branching of this region. In order to identify novel genes involved in the molecular regulation of branching morphogenesis we compared the gene expression profiles of isolated tip, trunk and MM cells using Compugen mouse long oligo microarrays. We identified genes enriched in the tip epithelium, sim-1, Arg2, Tacstd1, Crlf-1 and BMP7; genes enriched in the trunk epithelium, Innp1, Itm2b, Mkrn1, SPARC, Emu2 and Gsta3 and genes spatially restricted to the mesenchyme surrounding the trunk, CSPG2 and CV-2, with overlapping and complimentary expression to BMP4, respectively. This study has identified genes spatially expressed in regions of the developing kidney involved in branching morphogenesis, nephrogenesis and the development of the collecting duct system, calyces, renal pelvis and ureter. (c) 2006 Elsevier B.V. All rights reserved.
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In this paper I develop a version of universalism that is non-mereological. Broadly speaking, non-mereological universalism is the thesis that for any arbitrary set of objects and times, there is a persisting object which, at each of those times, will be constituted by those of the objects that exist at that time. I consider two general versions of non-mereological universalism, one which takes basic simples to be enduring objects, and the other which takes simples to be instantaneous objects. This yields three versions of endurantism, of which I ultimately defend the version I call universalist endurantism. Universalist endurantism is the thesis that (i) for any arbitrary set S of instantaneous simples that exist at the same instant, there exists a fusion of the members of S, and (ii) for any arbitrary set S* of instantaneous fusions each of which exist at a different instant, there exists an enduring object O that is constituted by those fusions at those instants. Universalist endurantism is ‘non-mereological’ in that the relation that holds between instantaneous fusions and persisting objects is not the part/whole relation, but rather, is the relation of constitution, thus allowing that the persisting objects are three rather than four dimensional. I argue that universalist endurantism not only has the various benefits of mereological universalism in allowing vagueness to be explicated as semantic indeterminacy, but in addition allows the endurantist to hold that some properties are genuinely intrinsic and are exemplified simpliciter.
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In this article we describe and evaluate the process of conducting online survey research about the legal recognition of same-sex relationships (key findings from which we have reported elsewhere, see Harding and Peel, 2006). Our aim in so doing is to contribute to the growing generic literature on internet-based research methods (Nosek et al., 2002; Rhodes et al., 2003; Stern, 2003; Strickland et al., 2003; Thomas et al., 2000) to the research methods literature within lesbian, gay, bisexual, trans and queer (LGBTQ) psychologies (Fish, 2000; Morris and Rothblum, 1999; Meezan and Martin, 2003; Mustanski, 2001) and also to extend the germinal literature focusing on internet research with non-heterosexual groups (Elford et al., 2004; Ellis et al., 2003; Ross et al., 2000). We begin by discussing the process of developing the online survey tool, before outlining the experience of the survey ‘going live’ and providing details of who completed the survey. We conclude by exploring some of the positives and pitfalls of this type of research methodology.