1,408 research outputs found
Popularity functions, partisan effects, and support in parliament
This paper analyzes the popularity of the main political entities in Portugal. Estimation results of popularity functions validate the responsibility hypothesis, with unemployment, and to a lesser extent inflation, affecting popularity levels. There is also evidence of personality effects, of popularity erosion over consecutive terms and of honeymoon effects. Finally, we found that voters' evaluations of incumbents' performance regarding unemployment is affected by their support in Parliament when an incumbent faces more opposition in Parliament, voters are less likely to hold him responsible for unemployment increases.(undefined
Adrenal steroids modulate the immune response during Brucella abortus infection by a mechanism that depends on the regulation of cytokine production
Human brucellosis is a protean disease with a diversity of clinical signs and symptoms resulting from infection with Brucella species. Recent reports suggest a cross-regulation between adrenal steroids (cortisol and dehydroepiandrosterone [DHEA]) and the immune system. Monocytes and macrophages are the main replication niche for Brucella. Therefore, we investigated the role of adrenal hormones on the modulation of the immune response mediated by macrophages in B. abortus infection. Cortisol treatment during B. abortus infection significantly inhibits cytokine, chemokine, and MMP-9 secretion. In contrast, DHEA treatment had no effect. However, DHEA treatment increases the expression of costimulatory molecules (CD40, CD86), the adhesion molecule CD54, and major histocompatibility complex class I (MHC-I) and MHC-II expression on the surface of B. abortus-infected monocytes. It is known that B. abortus infection inhibits MHC-I and MHC-II expression induced by gamma interferon (IFN-Îł) treatment. DHEA reverses B. abortus downmodulation of the MHC-I and -II expression induced by IFN-Îł. Taken together, our data indicate that DHEA immune intervention may positively affect monocyte activity during B. abortus infection.Fil: Gentilini, Maria Virginia. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Houssay. Instituto de InmunologĂa, GenĂ©tica y Metabolismo. Universidad de Buenos Aires. Facultad de Medicina. Instituto de InmunologĂa, GenĂ©tica y Metabolismo; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Hospital de ClĂnicas General San MartĂn; ArgentinaFil: Velasquez, Lis Noelia. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Barrionuevo, Paula. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Instituto de Medicina Experimental. Academia Nacional de Medicina de Buenos Aires. Instituto de Medicina Experimental; ArgentinaFil: Arriola Benitez, Paula Constanza. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Houssay. Instituto de InmunologĂa, GenĂ©tica y Metabolismo. Universidad de Buenos Aires. Facultad de Medicina. Instituto de InmunologĂa, GenĂ©tica y Metabolismo; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Hospital de ClĂnicas General San MartĂn; ArgentinaFil: Giambartolomei, Guillermo Hernan. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Houssay. Instituto de InmunologĂa, GenĂ©tica y Metabolismo. Universidad de Buenos Aires. Facultad de Medicina. Instituto de InmunologĂa, GenĂ©tica y Metabolismo; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Hospital de ClĂnicas General San MartĂn; ArgentinaFil: Delpino, MarĂa Victoria. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Houssay. Instituto de InmunologĂa, GenĂ©tica y Metabolismo. Universidad de Buenos Aires. Facultad de Medicina. Instituto de InmunologĂa, GenĂ©tica y Metabolismo; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Hospital de ClĂnicas General San MartĂn; Argentin
Government Spending Cycles: Ideological or Opportunistic?
ands. The time series analysis, covering the period 1953–1993, allows for different types of government spending. In general, spending is inspired by ideological and opportunistic motives: all government expenditure categories show an upward drift during election times and the partisan motives behind government spending are clearly revealed: left-wing cabinets attach greater importance to social security and health care than right-wing cabinets and right-wing cabinets value expenditure on infrastructure and defense more than left-wing parties.
Constructive comments by Frans van Winden, Wilko Letterie, Peter Cornelisse, Arie Ros, André de Moor, Harry ter Rele and an anonymous referee are gratefully acknowledged
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Advanced proton-exchange materials for energy efficient fuel cells.
The ''Advanced Proton-Exchange Materials for Energy Efficient Fuel Cells'' Laboratory Directed Research and Development (LDRD) project began in October 2002 and ended in September 2005. This LDRD was funded by the Energy Efficiency and Renewable Energy strategic business unit. The purpose of this LDRD was to initiate the fundamental research necessary for the development of a novel proton-exchange membranes (PEM) to overcome the material and performance limitations of the ''state of the art'' Nafion that is used in both hydrogen and methanol fuel cells. An atomistic modeling effort was added to this LDRD in order to establish a frame work between predicted morphology and observed PEM morphology in order to relate it to fuel cell performance. Significant progress was made in the area of PEM material design, development, and demonstration during this LDRD. A fundamental understanding involving the role of the structure of the PEM material as a function of sulfonic acid content, polymer topology, chemical composition, molecular weight, and electrode electrolyte ink development was demonstrated during this LDRD. PEM materials based upon random and block polyimides, polybenzimidazoles, and polyphenylenes were created and evaluated for improvements in proton conductivity, reduced swelling, reduced O{sub 2} and H{sub 2} permeability, and increased thermal stability. Results from this work reveal that the family of polyphenylenes potentially solves several technical challenges associated with obtaining a high temperature PEM membrane. Fuel cell relevant properties such as high proton conductivity (>120 mS/cm), good thermal stability, and mechanical robustness were demonstrated during this LDRD. This report summarizes the technical accomplishments and results of this LDRD
Directing Experimental Biology: A Case Study in Mitochondrial Biogenesis
Computational approaches have promised to organize collections of functional genomics data into testable predictions of gene and protein involvement in biological processes and pathways. However, few such predictions have been experimentally validated on a large scale, leaving many bioinformatic methods unproven and underutilized in the biology community. Further, it remains unclear what biological concerns should be taken into account when using computational methods to drive real-world experimental efforts. To investigate these concerns and to establish the utility of computational predictions of gene function, we experimentally tested hundreds of predictions generated from an ensemble of three complementary methods for the process of mitochondrial organization and biogenesis in Saccharomyces cerevisiae. The biological data with respect to the mitochondria are presented in a companion manuscript published in PLoS Genetics (doi:10.1371/journal.pgen.1000407). Here we analyze and explore the results of this study that are broadly applicable for computationalists applying gene function prediction techniques, including a new experimental comparison with 48 genes representing the genomic background. Our study leads to several conclusions that are important to consider when driving laboratory investigations using computational prediction approaches. While most genes in yeast are already known to participate in at least one biological process, we confirm that genes with known functions can still be strong candidates for annotation of additional gene functions. We find that different analysis techniques and different underlying data can both greatly affect the types of functional predictions produced by computational methods. This diversity allows an ensemble of techniques to substantially broaden the biological scope and breadth of predictions. We also find that performing prediction and validation steps iteratively allows us to more completely characterize a biological area of interest. While this study focused on a specific functional area in yeast, many of these observations may be useful in the contexts of other processes and organisms
Thermal Resonance in Signal Transmission
We use temperature tuning to control signal propagation in simple
one-dimensional arrays of masses connected by hard anharmonic springs and with
no local potentials. In our numerical model a sustained signal is applied at
one site of a chain immersed in a thermal environment and the signal-to-noise
ratio is measured at each oscillator. We show that raising the temperature can
lead to enhanced signal propagation along the chain, resulting in thermal
resonance effects akin to the resonance observed in arrays of bistable systems.Comment: To appear in Phys. Rev.
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