109 research outputs found
The Goldstone solar system radar: A science instrument for planetary research
The Goldstone Solar System Radar (GSSR) station at NASA's Deep Space Communications Complex in California's Mojave Desert is described. A short chronological account of the GSSR's technical development and scientific discoveries is given. This is followed by a basic discussion of how information is derived from the radar echo and how the raw information can be used to increase understanding of the solar system. A moderately detailed description of the radar system is given, and the engineering performance of the radar is discussed. The operating characteristics of the Arcibo Observatory in Puerto Rico are briefly described and compared with those of the GSSR. Planned and in-process improvements to the existing radar, as well as the performance of a hypothetical 128-m diameter antenna radar station, are described. A comprehensive bibliography of referred scientific and engineering articles presenting results that depended on data gathered by the instrument is provided
Notes on Stein-Sahi representations and some problems of non harmonic analysis
We discuss one natural class of kernels on pseudo-Riemannian symmetric
spaces.Comment: 40p
Neurocognitive profiles in help-seeking individuals: comparison of risk for psychosis and bipolar disorder criteria
Background. Neurocognitive deficits are important aspects of the schizophrenic disorders because they have a strong impact on social and vocational outcomes. We expanded on previous research by focusing on the neurocognitive profiles of persons at high risk (HR) or ultra-high risk (UHR) for schizophrenic and affective psychoses. Our main aim was to determine whether neurocognitive measures are sufficiently sensitive to predict a group affiliation based on deficits in functional domains. Method. This study included 207 help-seeking individuals identified as HR (n=75), UHR (n=102) or at high risk for bipolar disorder (HRBip; n=30), who were compared with persons comprising a matched, healthy control group (CG; n=50). Neuropsychological variables were sorted according to their load in a factor analysis and were compared among groups. In addition, the likelihood of group membership was estimated using logistic regression analyses. Results. The performance of HR and HRBip participants was comparable, and intermediate between the controls and UHR. The domain of processing speed was most sensitive in discriminating HR and UHR [odds ratio (OR) 0.48, 95% confidence interval (CI) 0.28-0.78, p=0.004] whereas learning and memory deficits predicted a conversion to schizophrenic psychosis (OR 0.47, 95% CI 0.25-0.87, p=0.01). Conclusions. Performances on neurocognitive tests differed among our three at-risk groups and may therefore be useful in predicting psychosis. Overall, cognition had a profound effect on the extent of general functioning and satisfaction with life for subjects at risk of psychosis. Thus, this factor should become a treatment target in itsel
Stein--Sahi complementary series and their degenerations
The aim of the paper is an introduction to Stein--Sahi complementary series,
holomorphic series, and 'unipotent representations'. We also discuss some open
problems related to these objects. For the sake of simplicity, we consider only
the groups U(n,n).Comment: 40pp, 7fig, revised versio
Selective inhibition of IL-6 trans-signaling by a miniaturized, optimized chimeric soluble gp130 inhibits TH17 cell expansion
The cytokine interleukin-6 (IL-6) signals through three mechanisms called classic signaling, trans-signaling, and trans-presentation. IL-6 trans-signaling is distinctly mediated through a soluble form of its transmembrane receptor IL-6R (sIL-6R) and the coreceptor gp130 and is implicated in multiple autoimmune diseases. Although a soluble form of gp130 (sgp130) inhibits only IL-6 trans-signaling, it also blocks an analogous trans-signaling mechanism of IL-11 and its soluble receptor sIL-11R. Here, we report miniaturized chimeric soluble gp130 variants that efficiently trap IL-6:sIL-6R but not IL-11:sIL-11R complexes. We designed a novel IL-6 trans-signaling trap by fusing a miniaturized sgp130 variant to an IL-6:sIL-6R complex–binding nanobody and the Fc portion of immunoglobulin G (IgG). This trap, called cs-130Fc, exhibited improved inhibition of as well as increased selectivity for IL-6 trans-signaling compared to the conventional fusion protein sgp130Fc. We introduced affinity-enhancing mutations in cs-130Fc and sgp130Fc that further improved selectivity toward IL-6 trans-signaling. Moreover, cs-130Fc efficiently inhibited the expansion of T helper 17 (TH17) cells in cultures of mouse CD4+ T cells treated with IL-6:sIL-6R. Thus, these variants may provide or lead to the development of more precisely targeted therapeutics for inflammatory disorders associated with IL-6 trans-signaling
Structure of a highly conserved domain of rock1 required for shroom-mediated regulation of cell morphology
Rho-associated coiled coil containing protein kinase (Rho-kinase or Rock) is a well-defined determinant of actin organization and dynamics in most animal cells characterized to date. One of the primary effectors of Rock is non-muscle myosin II. Activation of Rock results in increased contractility of myosin II and subsequent changes in actin architecture and cell morphology. The regulation of Rock is thought to occur via autoinhibition of the kinase domain via intramolecular interactions between the N-terminus and the C-terminus of the kinase. This autoinhibited state can be relieved via proteolytic cleavage, binding of lipids to a Pleckstrin Homology domain near the C-terminus, or binding of GTP-bound RhoA to the central coiled-coil region of Rock. Recent work has identified the Shroom family of proteins as an additional regulator of Rock either at the level of cellular distribution or catalytic activity or both. The Shroom-Rock complex is conserved in most animals and is essential for the formation of the neural tube, eye, and gut in vertebrates. To address the mechanism by which Shroom and Rock interact, we have solved the structure of the coiled-coil region of Rock that binds to Shroom proteins. Consistent with other observations, the Shroom binding domain is a parallel coiled-coil dimer. Using biochemical approaches, we have identified a large patch of residues that contribute to Shrm binding. Their orientation suggests that there may be two independent Shrm binding sites on opposing faces of the coiled-coil region of Rock. Finally, we show that the binding surface is essential for Rock colocalization with Shroom and for Shroom-mediated changes in cell morphology. © 2013 Mohan et al
The diversity and evolution of pollination systems in large plant clades: Apocynaceae as a case study
Background and Aims Large clades of angiosperms are often characterized by diverse interactions with pollinators, but how these pollination systems are structured phylogenetically and biogeographically is still uncertain for most families. Apocynaceae is a clade of >5300 species with a worldwide distribution. A database representing >10 % of species in the family was used to explore the diversity of pollinators and evolutionary shifts in pollination systems across major clades and regions. Methods The database was compiled from published and unpublished reports. Plants were categorized into broad pollination systems and then subdivided to include bimodal systems. These were mapped against the five major divisions of the family, and against the smaller clades. Finally, pollination systems were mapped onto a phylogenetic reconstruction that included those species for which sequence data are available, and transition rates between pollination systems were calculated. Key Results Most Apocynaceae are insect pollinated with few records of bird pollination. Almost three-quarters of species are pollinated by a single higher taxon (e.g. flies or moths); 7 % have bimodal pollination systems, whilst the remaining approx. 20 % are insect generalists. The less phenotypically specialized flowers of the Rauvolfioids are pollinated by a more restricted set of pollinators than are more complex flowers within the Apocynoids + Periplocoideae + Secamonoideae + Asclepiadoideae (APSA) clade. Certain combinations of bimodal pollination systems are more common than others. Some pollination systems are missing from particular regions, whilst others are over-represented. Conclusions Within Apocynaceae, interactions with pollinators are highly structured both phylogenetically and biogeographically. Variation in transition rates between pollination systems suggest constraints on their evolution, whereas regional differences point to environmental effects such as filtering of certain pollinators from habitats. This is the most extensive analysis of its type so far attempted and gives important insights into the diversity and evolution of pollination systems in large clades
Dominância fiscal : uma investigação empÃrica sobre o caso brasileiro no perÃodo de 2003 a 2014
A estabilização econômica dos anos de 1990 e a adoção do tripé econômico, a partir de
1999, marcam o fim de um capÃtulo delicado da história brasileira; a partir de então, era
necessária a existência de certa sintonia de polÃticas monetária e fiscal para a
manutenção do controle dos diversos indicadores econômicos. Contudo, com essa
reciprocidade na polÃtica econômica, são incitadas discussões sobre a orientação do
governo na hora de definir suas prioridades nesse campo: as variáveis fiscais são
priorizadas e, por conseguinte, determinadas, forçando as monetárias a se ajustarem –
ou o contrário? A resposta para esse questionamento leva à discussão sobre a
dominância fiscal. Assim, esse trabalho visa verificar empiricamente, usando das
modelagens econométricas VAR e estudo de eventos, se há dominância fiscal ou
monetária na economia brasileira e se a eficácia da polÃtica monetária mudou na
transição do governo Lula para o governo Dilma. O resultado foi inconclusivo para o
governo Lula e indicou dominância fiscal no governo Dilma. Ainda verificou-se não
haver modificação na eficácia da polÃtica monetária.Economic stabilization, in the 1990s, and utilization of an economic tripod, after 1999,
represents the end of a delicate chapter in Brazilian history. Ever since, it was necessary
the existence of a certain agreement between monetary and fiscal politic, in order to
maintain under control a variety of economic indicators. However, this reciprocity (in
economic politic) starts discussions about the real government orientations when it
comes to define its priority on this subject: are the fiscal variables priorized, and then,
determined, forcing monetary variables to adjust themselves, or the opposite? The
answer to these questions emerge from the fiscal dominance discussion. This paper
intends to empiric verify, using econometric modeling VAR and event study, if there is
fiscal dominance or monetary in Brazilian economy and whether the effectiveness of
monetary politic has changed in the transition from Lula's government to the Dilma
government. The result was inconclusive for the Lula government and indicated fiscal
dominance in the Dilma government. There was still no change in the efficiency of the
monetary politic.CAPE
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