Implicaciones sociales de la política tributaria en México en la década de los setenta

Tesina (Licenciatura en Sociología) -- Universidad Autónoma Metropolitana, Unidad Azcapotzalco, División de Ciencias Sociales y Humanidades, Departamento de Sociología, 1981. UAMADCSHDS. 1 archivo PDF (121 páginas

Modelling the impact of women’s education on fertility in Malawi

Many studies have suggested that there is an inverse relationship between education and number of children among women from sub-Saharan Africa countries, including Malawi. However, a crucial limitation of these analyses is that they do not control for the potential endogeneity of education. The aim of our study is to estimate the role of women’s education on their number of children in Malawi, accounting for the possible presence of endogeneity and for nonlinear effects of continuous observed confounders. Our analysis is based on micro data from the 2010 Malawi Demographic Health Survey, and uses a flexible instrumental variable regression approach. The results suggest that the relationship of interest is affected by endogeneity and exhibits an inverted U-shape among women living in rural areas of Malawi, whereas it exhibits an inverse (nonlinear) relationship for women living in urban areas

Ultrastructural and functional fate of recycled vesicles in hippocampal synapses

Efficient recycling of synaptic vesicles is thought to be critical for sustained information transfer at central terminals. However, the specific contribution that retrieved vesicles make to future transmission events remains unclear. Here we exploit fluorescence and time-stamped electron microscopy to track the functional and positional fate of vesicles endocytosed after readily releasable pool (RRP) stimulation in rat hippocampal synapses. We show that most vesicles are recovered near the active zone but subsequently take up random positions in the cluster, without preferential bias for future use. These vesicles non-selectively queue, advancing towards the release site with further stimulation in an actin-dependent manner. Nonetheless, the small subset of vesicles retrieved recently in the stimulus train persist nearer the active zone and exhibit more privileged use in the next RRP. Our findings reveal heterogeneity in vesicle fate based on nanoscale position and timing rules, providing new insights into the origins of future pool constitution

Chronic unpredictable stress regulates visceral adipocyte-mediated glucose metabolism and inflammatory circuits in male rats

Chronic psychological stress is a prominent risk factor involved in the pathogenesis of many complex diseases, including major depression, obesity, and type II diabetes. Visceral adipose tissue is a key endocrine organ involved in the regulation of insulin action and an important component in the development of insulin resistance. Here, we examined for the first time the changes on visceral adipose tissue physiology and on adipocyte-associated insulin sensitivity and function after chronic unpredictable stress in rats. Male rats were subjected to chronic unpredictable stress for 35 days. Total body and visceral fat was measured. Cytokines and activated intracellular kinase levels were determined using high-throughput multiplex assays. Adipocyte function was assessed via tritiated glucose uptake assay. Stressed rats showed no weight gain, and their fat/lean mass ratio increased dramatically compared to control animals. Stressed rats had significantly higher mesenteric fat content and epididymal fat pad weight and demonstrated reduced serum glucose clearing capacity following glucose challenge. Alterations in fat depot size were mainly due to changes in adipocyte numbers and not size. High-throughput molecular screening in adipocytes isolated from stressed rats revealed activation of intracellular inflammatory, glucose metabolism, and MAPK networks compared to controls, as well as significantly reduced glucose uptake capacity in response to insulin stimulation. Our study identifies the adipocyte as a key regulator of the effects of chronic stress on insulin resistance, and glucose metabolism, with important ramifications in the pathophysiology of several stress-related disease states

Energy spread of ultracold electron bunches extracted from a laser cooled gas

Ultrashort and ultracold electron bunches created by near-threshold femtosecond photoionization of a laser-cooled gas hold great promise for single-shot ultrafast diffraction experiments. In previous publications the transverse beam quality and the bunch length have been determined. Here the longitudinal energy spread of the generated bunches is measured for the first time, using a specially developed Wien filter. The Wien filter has been calibrated by determining the average deflection of the electron bunch as a function of magnetic field. The measured relative energy spread $\frac{\sigma_{U}}{U} = 0.64 \pm 0.09\%$ agrees well with the theoretical model which states that it is governed by the width of the ionization laser and the acceleration length

An assessment of validity and responsiveness of generic measures of health-related quality of life in hearing impairment

This article is made available through the Brunel Open Access Publishing Fund. This article is distributed under the terms of the Creative Commons Attribution License which permits any use, distribution, and reproduction in any medium, provided the original author(s) and the source are credited.Purpose: This review examines psychometric performance of three widely used generic preference-based measures, that is, EuroQol 5 dimensions (EQ-5D), Health Utility Index 3 (HUI3) and Short-form 6 dimensions (SF-6D) in patients with hearing impairments. Methods: A systematic search was undertaken to identify studies of patients with hearing impairments where health state utility values were measured and reported. Data were extracted and analysed to assess the reliability, validity (known group differences and convergent validity) and responsiveness of the measures across hearing impairments. Results: Fourteen studies (18 papers) were included in the review. HUI3 was the most commonly used utility measures in hearing impairment. In all six studies, the HUI3 detected difference between groups defined by the severity of impairment, and four out of five studies detected statistically significant changes as a result of intervention. The only study available suggested that EQ-5D only had weak ability to discriminate difference between severity groups, and in four out of five studies, EQ-5D failed to detected changes. Only one study involved the SF-6D; thus, the information is too limited to conclude on its performance. Also evidence for the reliability of these measures was not found. Conclusion: Overall, the validity and responsiveness of the HUI3 in hearing impairment was good. The responsiveness of EQ-5D was relatively poor and weak validity was suggested by limited evidence. The evidence on SF-6D was too limited to make any judgment. More head-to-head comparisons of these and other preference measures of health are required.Medical Research Counci

High-precision optical-frequency dissemination on branching optical-fiber networks

We present a technique for the simultaneous dissemination of high-precision optical-frequency signals to multiple independent remote sites on a branching optical-fiber network. The technique corrects optical-fiber length fluctuations at the output of the link, rather than at the input as is conventional. As the transmitted optical signal remains unaltered until it reaches the remote site, it can be transmitted simultaneously to multiple remote sites on an arbitrarily complex branching network. This technique maintains the same servo-loop bandwidth limit as in conventional techniques and is compatible with active telecommunication links.Sascha W. Schediwy, David Gozzard, Kenneth G. H. Baldwin, Brian J. Orr, R. Bruce Warrington, Guido Aben and Andre N. Luite

Estimations of the cosmological parameters from the observational variation of the fine structure constant

We present the constraints on the Quintessence scalar field model from the observational data of the variation of the fine structure constant obtained from Keck and VLT telescopes. Within the theoretical frame proposed by Bekenstein, the constraints on the parameters of the Quintessence scalar field model are obtained. By the consideration of the prior of $\Omega_{m0}$ as WMAP 7 suggests, we obtain various results of the different samples. Based on these results, we also calculate the probability density function of the coupling constant $\zeta$. The best-fit values show a consistent relationship between $\zeta$ and the different experimental results. In our work, we test two different potential models, namely, the inverse power law potential and the exponential potential. The results show that both the large value of the parameters in the potential and the strong coupling can cause the variation of fine structure constant.Comment: 17 pages, 10 figures, 1 table. Joint constraints added, a few comments added. Accepted for publication in RAA. Updated to match the accepted versio

Interpreting cerebrospinal fluid pleocytosis in HIV in the era of potent antiretroviral therapy

Background: Cerebrospinal fluid (CSF) pleocytosis may be seen in asymptomatic HIV-infected individuals. This finding complicates interpretation of CSF abnormalities when such individuals are evaluated for other central nervous system infections. The goal of this study was to determine the relationship between CSF pleocytosis, central nervous system (CNS) antiretroviral penetration, adherence to antiretroviral medication regimens, neurological symptoms and performance on neuropsychological tests. Methods: Clinically stable HIV-infected individuals at any peripheral blood CD4+ T cell count or any plasma viral load were asked to attend study visits at entry and every 6 months thereafter for at least one year. At each visit, they underwent a standardized neurological and medication history; neurological examination; a brief neuropsychological test battery: venipuncture; lumbar puncture; and assessment of medication adherence. Generalized estimating equations (GEE) were used to assess the relationships between CSF pleocytosis and other variables. Results: CSF pleocytosis was independently and significantly related to lack of current antiretroviral use (OR 5.9, 95% CI 1.8-18.6, p = 0.003), CD4 count >200/ul (OR 23.4, 95% CI 3.1-177.3, p = 0.002) and detectable plasma HIV RNA (OR 3.3, 95% CI 1.1-9.4, p = 0.03). At visits where antiretrovirals were used, and taking into account detectable plasma HIV RNA, an antiretroviral regimen that contained two or more agents with good CNS penetration conferred a trend toward lower odds of CSF pleocytosis (OR 0.45, 95% CI 0.18-1.12, p = 0.087). Conclusion: CSF pleocytosis is a characteristic of HIV disease that varies significantly with easily identifiable clinical and laboratory features. Use of antiretroviral agents decreases the odds of pleocytosis. This association may be stronger when the regimen contains two or more agents with good CNS penetration.This work was supported by National Institutes of Health grant U54 NS 39406 (AI and CMM)

Pyruvate Kinase Inhibits Proliferation during Postnatal Cerebellar Neurogenesis and Suppresses Medulloblastoma Formation

Aerobic glycolysis supports proliferation through unresolved mechanisms. We have previously shown that aerobic glycolysis is required for the regulated proliferation of cerebellar granule neuron progenitors (CGNP) and for the growth of CGNP-derived medulloblastoma. Blocking the initiation of glycolysis via deletion of hexokinase-2 (Hk2) disrupts CGNP proliferation and restricts medulloblastoma growth. Here, we assessed whether disrupting pyruvate kinase-M (Pkm), an enzyme that acts in the terminal steps of glycolysis, would alter CGNP metabolism, proliferation, and tumorigenesis. We observed a dichotomous pattern of PKM expression, in which postmitotic neurons throughout the brain expressed the constitutively active PKM1 isoform, while neural progenitors and medulloblastomas exclusively expressed the less active PKM2. Isoform-specific Pkm2 deletion in CGNPs blocked all Pkm expression. Pkm2-deleted CGNPs showed reduced lactate production and increased SHH-driven proliferation.13C-flux analysis showed that Pkm2 deletion reduced the flow of glucose carbons into lactate and glutamate without markedly increasing glucose-to-ribose flux. Pkm2 deletion accelerated tumor formation in medulloblastoma- prone ND2:SmoA1 mice, indicating the disrupting PKM releases CGNPs from a tumor-suppressive effect. These findings show that distal and proximal disruptions of glycolysis have opposite effects on proliferation, and that efforts to block the oncogenic effect of aerobic glycolysis must target reactions upstream of PKM