906 resultados para Determinants and SIGIC
Dimensions and determinants of upward mobility : a study based on longitudinal data from Delhi slums
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This study based on two primary surveys of the same households in two different years (2007/08 and 2012) assesses the extent of inter-temporal change in income of the individual workers and makes an attempt to identify the factors which explain upward mobility in alternate econometric framework, envisaging endogeneity problem. It also encompasses a host of indicators of wellbeing and constructs the transition matrix to capture the extent of change over time at the household level. The findings are indicative of a rise in the income of workers across a sizeable percentage of households though many of them remained below the poverty line notwithstanding this increase. In fact, there is a wide spread deterioration in the wellbeing index constructed at the household level. Among several determinants of income rise two important policy prescriptions can be elicited. Inadequate education reduces the probability of upward mobility while education above a threshold level raises it. Savings are crucial for upward mobility impinging on the importance of asset creation. Views that entail neighbourhood spill-over effects also received validation. Besides, investment in housing and basic amenities turns out to be crucial for improvement in wellbeing levels.
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La comprensión actual de la heterogeneidad de las empresas académico rendimiento en el entorno entra industria necesita un mayor desarrollo. Gestión estratégica y el discurso sobre la literatura empresarial necesita mayor explicación de por qué los modelos de negocio aparentemente similares en el mismo sector actúan de forma diferente. También qué factores del entorno sectorial y operativo determina el surgimiento y funcionamiento de los modelos de negocio sostenibles e innovadoras permanecen sin explorar. Un marco se conceptualiza acompañado de estudios de caso sobre la compañía aérea y las industrias de energía renovable. El estudio lleva a una visión basada en los recursos de los modelos de negocio que las empresas alcancen posiciones heterogéneas de recursos. Una explicación para la heterogeneidad firme desempeño que se busca por intermediación conocimiento que genera valor a partir de la utilización eficaz de los recursos de conocimientos adquiridos a entornos entra y inter-empresa. Un marco para la aparición de nuevos modelos de negocios verdes se conceptualiza y deducciones se obtienen mediante un estudio de caso sobre la base de la industria de biocombustibles de energías renovables para explicar la dinámica de los mercados verdes y cómo se puede crear valor sostenible y capturó e innovadora de los modelos de negocios verdes. El marco desarrollado proporciona una visión cíclica de la flexibilidad del modelo de negocio en la que se propaga la acumulación de recursos basada en el conocimiento del modelo de negocio a través de los ambientes dentro y inter-empresa. Estrategias de conocimiento de corretaje del resultado ambientes inter e dentro-firma en un mejor desempeño del modelo de negocio. La flexibilidad del modelo de negocio que adquiere está determinada por la eficiencia con la acumulación de recursos está alineado con su ambiente externo. Las características de la que el modelo de negocio alcanza ventajas competitivas, como la innovación y la flexibilidad se atribuyen a la heterogeneidad de los recursos. La investigación se extiende a la literatura orientación de servicio al conceptualizar y medir la orientación a servicios como un requisito clave para la innovación del modelo de negocio, mientras que aboga por la necesidad de identificar correctamente las competencias básicas de la empresa, especialmente relevante en el contexto de la empresa orientada a los servicios, donde la creación de valor requiere recursos y la prestación eficiente de los servicios. La investigación trata de llegar a una descripción de los modelos de negocio sostenibles verdes y argumenta que la innovación, la flexibilidad y la sostenibilidad son los tres habilitadores básicos de los cuales el concepto de modelo de negocio verde puede evolucionar la explotación de nuevos mecanismos de mercado y los mercados para crear y capturar valor en el mantenimiento de su innovadora ambiente externo. La investigación integra efectivamente los conceptos de corretaje de conocimientos y modelos de negocio a partir de un recurso basado en la acumulación de vista y al mismo tiempo llega a la heterogeneidad rendimiento de los modelos de negocio aparentemente similares dentro de la misma industria. La investigación indica cómo se producen perturbaciones del mercado en una industria como resultado de modelos de negocio innovador y flexible, y cómo los nuevos modelos de negocio evolucionan en base a estos trastornos. Avanza la comprensión de cómo la estrategia de núcleo competencia y la innovación del modelo de negocio construcciones se comportan en el esfuerzo de la empresa de servicios para obtener una ventaja competitiva sostenible. Los resultados tienen implicaciones en el rendimiento de las empresas que empiezan sin recursos distintos de los suyos, o que utilizan un modelo de negocio imitado, para lograr un mejor rendimiento a través de la evolución del modelo de negocio alineado con las exitosas estrategias de conocimiento de corretaje. Dicho marco puede permitir a las empresas a evaluar y elegir un modelo de negocio basado en la innovación, la flexibilidad, la sostenibilidad y las opciones para el cambio. La investigación se suma a la literatura acumulación de recursos, explicando cómo los recursos pueden ser efectivamente adquirida para crear valor. La investigación también se suma a la literatura empresarial verde, explicando cómo las empresas crear y capturar valor en los nuevos mecanismos dinámicos de mercado.
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Virus emergence is a complex phenomenon, which generally involves spread to a new host from a wild host, followed by adaptation to the new host. Although viruses account for the largest fraction of emerging crop pathogens, knowledge about their emergence is incomplete. We address here the question of whether Pepino mosaic virus (PepMV) emergence as a major tomato pathogen worldwide could have involved spread from wild to cultivated plant species and host adaptation. For this, we surveyed natural populations of wild tomatoes in southern Peru for PepMV infection. PepMV incidence, genetic variation, population structure, and accumulation in various hosts were analyzed. PepMV incidence in wild tomatoes was high, and a strain not yet reported in domestic tomato was characterized. This strain had a wide host range within the Solanaceae, multiplying efficiently in most assayed Solanum species and being adapted to wild tomato hosts. Conversely, PepMV isolates from tomato crops showed evidence of adaptation to domestic tomato, possibly traded against adaptation to wild tomatoes. Phylogenetic reconstructions indicated that the most probable ancestral sequence came from a wild Solanum species. A high incidence of PepMV in wild tomato relatives would favor virus spread to crops and its efficient multiplication in different Solanum species, including tomato, allowing its establishment as an epidemic pathogen. Later, adaptation to tomato, traded off against adaptation to other Solanum species, would isolate tomato populations from those in other hosts.
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Sigma 54 is a required factor for bacterial RNA polymerase to respond to enhancers and directs a mechanism that is a hybrid between bacterial and eukaryotic transcription. Three pathways were found that bypass the enhancer requirement in vitro. These rely on either deletion of the sigma 54 N terminus or destruction of the DNA consensus −12 promoter recognition element or altering solution conditions to favor transient DNA melting. Each of these allows unstable heparin-sensitive pre-initiation complexes to form that can be driven to transcribe in the absence of both enhancer protein and ATP β–γ hydrolysis. These disparate pathways are proposed to have a common basis in that multiple N-terminal contacts may mediate the interactions between the polymerase and the DNA region where melting originates. The results raise possibilities for common features of open complex formation by different RNA polymerases.
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Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2015. For permissions please email: journals.permissions@oup.com.
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Peer reviewed
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T cells recognizing poorly displayed self determinants escape tolerance mechanisms and persist in the adult repertoire. The process by which these T cells are primed is not clear, but once activated, they can cause autoimmunity. Here, we show that dendritic cells treated with interleukin 6 (IL-6) process and present determinants from a model native antigen in a qualitatively altered hierarchy, activating T cells in vitro and in vivo against determinants that were previously cryptic because of poor display. IL-6 does not induce conventional maturation of dendritic cells but alters the pH of peripheral, early endosomal compartments and renders the cells more susceptible to killing by chloroquine. Acidification of endosomes by ouabain mimics the effect of IL-6 and allows processing of the same cryptic determinant. These results suggest that cytokines such as IL-6 could initiate and help to propagate an autoimmune disease process by differentiating dendritic cells into a state distinct from that induced by normal maturation.
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Modulation of the N-methyl-d-aspartate (NMDA)-selective glutamate receptors by extracellular protons and Zn2+ may play important roles during ischemia in the brain and during seizures. Recombinant NR1/NR2A receptors exhibit a much higher apparent affinity for voltage-independent Zn2+ inhibition than receptors with other subunit combinations. Here, we show that the mechanism of this apparent high-affinity, voltage-independent Zn2+ inhibition for NR2A-containing receptors results from the enhancement of proton inhibition. We also show that the N-terminal leucine/isoleucine/valine binding protein (LIVBP)-like domain of the NR2A subunit contains critical determinants of the apparent high-affinity, voltage-independent Zn2+ inhibition. Mutations H42A, H44G, or H128A greatly increase the Zn2+ IC50 (by up to ≈700-fold) with no effect on the potencies of glutamate and glycine or on voltage-dependent block by Mg2+. Furthermore, the amino acid residue substitution H128A, which mediates the largest effect on the apparent high-affinity Zn2+ inhibition among all histidine substitutions we tested, is also critical to the pH-dependency of Zn2+ inhibition. Our data revealed a unique interaction between two important extracellular modulators of NMDA receptors.
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Objectives: To determine the demands on healthcare resources caused by different types of illnesses and variation with age and sex.
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Ribosomal protein S7 from Escherichia coli binds to the lower half of the 3′ major domain of 16S rRNA and initiates its folding. It also binds to its own mRNA, the str mRNA, and represses its translation. Using filter binding assays, we show in this study that the same mutations that interfere with S7 binding to 16S rRNA also weaken its affinity for its mRNA. This suggests that the same protein regions are responsible for mRNA and rRNA binding affinities, and that S7 recognizes identical sequence elements within the two RNA targets, although they have dissimilar secondary structures. Overexpression of S7 is known to inhibit bacterial growth. This phenotypic growth defect was relieved in cells overexpressing S7 mutants that bind poorly the str mRNA, confirming that growth impairment is controlled by the binding of S7 to its mRNA. Interestingly, a mutant with a short deletion at the C-terminus of S7 was more detrimental to cell growth than wild-type S7. This suggests that the C-terminal portion of S7 plays an important role in ribosome function, which is perturbed by the deletion.
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In skeletal muscle, transcription of the gene encoding the mouse type Iα (RIα) subunit of the cAMP-dependent protein kinase is initiated from the alternative noncoding first exons 1a and 1b. Here, we report that activity of the promoter upstream of exon 1a (Pa) depends on two adjacent E boxes (E1 and E2) in NIH 3T3-transfected fibroblasts as well as in intact muscle. Both basal activity and MyoD transactivation of the Pa promoter require binding of the upstream stimulating factors (USF) to E1. E2 binds either an unknown protein in a USF/E1 complex-dependent manner or MyoD. Both E2-bound proteins seem to function as repressors, but with different strengths, of the USF transactivation potential. Previous work has shown localization of the RIα protein at the neuromuscular junction. Using DNA injection into muscle of plasmids encoding segments of RIα or RIIα fused to green fluorescent protein, we demonstrate that anchoring at the neuromuscular junction is specific to RIα subunits and requires the amino-terminal residues 1–81. Mutagenesis of Phe-54 to Ala in the full-length RIα–green fluorescent protein template abolishes localization, indicating that dimerization of RIα is essential for anchoring. Moreover, two other hydrophobic residues, Val-22 and Ile-27, are crucial for localization of RIα at the neuromuscular junction. These amino acids are involved in the interaction of the Caenorhabditis elegans type Iα homologue RCE with AKAPCE and for in vitro binding of RIα to dual A-kinase anchoring protein 1. We also show enrichment of dual A-kinase anchoring protein 1 at the neuromuscular junction, suggesting that it could be responsible for RIα tethering at this site.
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Escherichia coli RNA polymerase (RNAP) alpha subunit serves as the initiator for RNAP assembly, which proceeds according to the pathway 2 alpha-->alpha 2-->alpha 2 beta-->alpha 2 beta beta'-->alpha 2 beta beta' sigma. In this work, we have used hydroxyl-radical protein footprinting to define determinants of alpha for interaction with beta, beta', and sigma. Our results indicate that amino acids 30-75 of alpha are protected from hydroxyl-radical-mediated proteolysis upon interaction with beta (i.e., in alpha 2 beta, alpha 2 beta beta', and alpha 2 beta beta' sigma), and amino acids 175-210 of alpha are protected from hydroxyl-radical-mediated proteolysis upon interaction with beta' (i.e., in alpha 2 beta beta' and alpha 2 beta beta' sigma). The protected regions are conserved in the alpha homologs of prokaryotic, eukaryotic, archaeal, and chloroplast RNAPs and contain sites of substitutions that affect RNAP assembly. We conclude that the protected regions define determinants of alpha for direct functional interaction with beta and beta'. The observed maximal magnitude of protection upon interaction with beta and the observed maximal magnitude of protection upon interaction with beta' both correspond to the expected value for complete protection of one of the two alpha protomers of RNAP (i.e., 50% protection). We propose that only one of the two alpha protomers of RNAP interacts with beta and that only one of the two alpha protomers of RNAP interacts with beta'.
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Voltage-gated Na+ channels are the molecular targets of local anesthetics, class I antiarrhythmic drugs, and some anticonvulsants. These chemically diverse drugs inhibit Na+ channels with complex voltage- and frequency-dependent properties that reflect preferential drug binding to open and inactivated channel states. The site-directed mutations F1764A and Y1771A in transmembrane segment IVS6 of type IIA Na+ channel alpha subunits dramatically reduce the affinity of inactivated channels for the local anesthetic etidocaine. In this study, we show that these mutations also greatly reduce the sensitivity of Na+ channels to state-dependent block by the class Ib antiarrhythmic drug lidocaine and the anticonvulsant phenytoin and, to a lesser extent, reduce the sensitivity to block by the class Ia and Ic antiarrhythmic drugs quinidine and flecainide. For lidocaine and phenytoin, which bind preferentially to inactivated Na+ channels, the mutation F1764A reduced the affinity for binding to the inactivated state 24.5-fold and 8.3-fold, respectively, while Y1771A had smaller effects. For quinidine and flecainide, which bind preferentially to the open Na+ channels, the mutations F1764A and Y1771A reduced the affinity for binding to the open state 2- to 3-fold. Thus, F1764 and Y1771 are common molecular determinants of state-dependent binding of diverse drugs including lidocaine, phenytoin, flecainide, and quinidine, suggesting that these drugs interact with a common receptor site. However, the different magnitude of the effects of these mutations on binding of the individual drugs indicates that they interact in an overlapping, but nonidentical, manner with a common receptor site. These results further define the contributions of F1764 and Y1771 to a complex drug receptor site in the pore of Na+ channels.