661 research outputs found
A photometric and spectroscopic survey of solar twin stars within 50 parsecs of the Sun: I. Atmospheric parameters and color similarity to the Sun
Solar twins and analogs are fundamental in the characterization of the Sun's
place in the context of stellar measurements, as they are in understanding how
typical the solar properties are in its neighborhood. They are also important
for representing sunlight observable in the night sky for diverse photometric
and spectroscopic tasks, besides being natural candidates for harboring
planetary systems similar to ours and possibly even life-bearing environments.
We report a photometric and spectroscopic survey of solar twin stars within 50
pc of the Sun. Hipparcos absolute magnitudes and (B-V)_Tycho colors were used
to define a 2 sigma box around the solar values, where 133 stars were
considered. Additional stars resembling the solar UBV colors in a broad sense,
plus stars present in the lists of Hardorp, were also selected. All objects
were ranked by a color-similarity index with respect to the Sun, defined by
uvby and BV photometry. Moderately high-resolution, high-S/N spectra were used
for a subsample of equatorial-southern stars to derive Teff, log g, and [Fe/H]
with average internal errors better than 50 K, 0.20 dex, and 0.08 dex,
respectively. Ages and masses were estimated from theoretical HR diagrams. The
color-similarity index proved very successful. We identify and rank new
excellent solar analogs, which are fit to represent the Sun in the night sky.
Some of them are faint enough to be of interest for moderately large
telescopes. We also identify two stars with near-UV spectra indistinguishable
from the Sun's. We present five new "probable" solar twin stars, besides five
new "possible" twins. Masses and ages for the best solar twin candidates lie
very close to the solar values, but chromospheric activity levels range
somewhat. We propose that the solar twins be emphasized in the ongoing searches
for extra-solar planets and SETI searches.Comment: 25 pages, 15 figures, 14 table
Metabolic and transcriptomic analysis of Huntington's disease model reveal changes in intracellular glucose levels and related genes.
Huntington's Disease (HD) is a neurodegenerative disorder caused by an expansion in a CAG-tri-nucleotide repeat that introduces a poly-glutamine stretch into the huntingtin protein (mHTT). Mutant huntingtin (mHTT) has been associated with several phenotypes including mood disorders and depression. Additionally, HD patients are known to be more susceptible to type II diabetes mellitus (T2DM), and HD mice model develops diabetes. However, the mechanism and pathways that link Huntington's disease and diabetes have not been well established. Understanding the underlying mechanisms can reveal potential targets for drug development in HD. In this study, we investigated the transcriptome of mHTT cell populations alongside intracellular glucose measurements using a functionalized nanopipette. Several genes related to glucose uptake and glucose homeostasis are affected. We observed changes in intracellular glucose concentrations and identified altered transcript levels of certain genes including Sorcs1, Hh-II and Vldlr. Our data suggest that these can be used as markers for HD progression. Sorcs1 may not only have a role in glucose metabolism and trafficking but also in glutamatergic pathways affecting trafficking of synaptic components
Denoising Opponents Position in Partial Observation Environment
The RoboCup competitions hold various leagues, and the Soccer Simulation 2D
League is a major among them. Soccer Simulation 2D (SS2D) match involves two
teams, including 11 players and a coach for each team, competing against each
other. The players can only communicate with the Soccer Simulation Server
during the game. Several code bases are released publicly to simplify team
development. So researchers can easily focus on decision-making and
implementing machine learning methods. SS2D actions and behaviors are only
partially accurate due to different challenges, such as noise and partial
observation. Therefore, one strategy is to implement alternative denoising
methods to tackle observation inaccuracy. Our idea is to predict opponent
positions while they have yet to be seen in a finite number of cycles using
machine learning methods to make more accurate actions such as pass. We will
explain our position prediction idea powered by Long Short-Term Memory models
(LSTM) and Deep Neural Networks (DNN). The results show that the LSTM and DNN
predict the opponents' position more accurately than the standard algorithm,
such as the last-seen method
Treatment priorities in oncology: do we want to live longer or better?
OBJECTIVES: Despite the progress achieved in the fight against cancer over the past several years, assessing the needs, goals and preferences of patients with cancer is of the utmost importance for the delivery of health care. We sought to assess priorities regarding quantity versus quality of life among Brazilian patients, comparing them with individuals without cancer. METHODS: Using a questionnaire presenting four hypothetical cancer cases, we interviewed cancer patients, oncology health-care professionals and laypersons, most of whom had administrative functions in our hospital. RESULTS: A total of 214 individuals participated: 101 patients, 44 health-care professionals and 69 laypersons. The mean ages in the three groups were 56, 34 and 31 years old, respectively (
Social entrepreneurship in the interface between public communication and social capital
This article, which is based on socio-psychological theory and critical theory, addresses the social entrepreneurship from the perspective of public communication and social capital. The purpose is to analyze how the correlation between those concepts can present an option for social development, since, in the context of democracy, a conception of development cannot be tied only to the logic of the market that privileges the private gains to the detriment of the public interest. The notion of a social entrepreneur becomes relevant by the perspective of the feasibility of actions aimed at the sustainability of the third sector and other perspectives of social action, which, although using management processes, oppose the view of competition with the view of cooperation; it values social capital rather than evidencing the economic capital; it creates a new meaning for the capitalist logic to a more human side, in which the economic topic serves the social development.Este artigo, que tem por base a teoria sociopsicológica e a teoria crítica, trata do empreendedorismo social sob a perspectiva da comunicação pública e do capital social. O objetivo é analisar como a correlação desses conceitos é capaz de apresentar uma opção para o desenvolvimento social, já que, no contexto de democracia, uma concepção de desenvolvimento não pode estar atrelada apenas à lógica do mercado que privilegia os ganhos particulares em detrimento do interesse público. A noção de empreendedor social passa a ser útil sob o ponto de vista da viabilidade de ações que visem à sustentabilidade do terceiro setor e de outras perspectivas de atuação social, que, mesmo se valendo de processos de gestão, contrapõem a visão de competição com a visão de cooperação; valoriza o capital social ao invés de evidenciar o capital econômico; ressignifica a lógica capitalista para uma vertente mais humana, em que a questão econômica sirva ao desenvolvimento social.Este artículo, que se basa en la teoría sociopsicológica y la teoría crítica, trata del emprendedorismo social desde la perspectiva de la comunicación pública y del capital social. El objetivo es analizar cómo la correlación de estos conceptos es capaz de presentar una opción para el desarrollo social, ya que, en el contexto de la democracia, una concepción de desarrollo no puede estar ligada sólo a la lógica del mercado que privilegia las ganancias particulares en detrimento del interés público. La noción de emprendedor social pasa a ser útil desde el punto de vista de la viabilidad de acciones que apunte a la sostenibilidad del tercer sector y de otras perspectivas de actuación social, que, aun valiéndose de procesos de gestión, contrapone la visión de competencia con la visión de cooperación; valoriza el capital social en lugar de evidenciar el capital económico; resignifica la lógica capitalista hacia una vertiente más humana, en que la cuestión económica sirva al desarrollo social
Glycosaminoglycans affect the interaction of human plasma kallikrein with plasminogen, factor XII and inhibitors
Human plasma kallikrein, a serine proteinase, plays a key role in intrinsic blood clotting, in the kallikrein-kinin system, and in fibrinolysis. The proteolytic enzymes involved in these processes are usually controlled by specific inhibitors and may be influenced by several factors including glycosaminoglycans, as recently demonstrated by our group. The aim of the present study was to investigate the effect of glycosaminoglycans (30 to 250 µg/ml) on kallikrein activity on plasminogen and factor XII and on the inhibition of kallikrein by the plasma proteins C1-inhibitor and antithrombin. Almost all available glycosaminoglycans (heparin, heparan sulfate, bovine and tuna dermatan sulfate, chondroitin 4- and 6-sulfates) reduced (1.2 to 3.0 times) the catalytic efficiency of kallikrein (in a nanomolar range) on the hydrolysis of plasminogen (0.3 to 1.8 µM) and increased (1.9 to 7.7 times) the enzyme efficiency in factor XII (0.1 to 10 µM) activation. On the other hand, heparin, heparan sulfate, and bovine and tuna dermatan sulfate improved (1.2 to 3.4 times) kallikrein inhibition by antithrombin (1.4 µM), while chondroitin 4- and 6-sulfates reduced it (1.3 times). Heparin and heparan sulfate increased (1.4 times) the enzyme inhibition by the C1-inhibitor (150 nM).Universidade Federal de São Paulo (UNIFESP) Escola Paulista de Medicina Departamento de BioquímicaUniversidade Federal de São Paulo (UNIFESP) Escola Paulista de Medicina Departamento de BiofísicaUNIFESP, EPM, Depto. de BioquímicaUNIFESP, EPM, Depto. de BiofísicaSciEL
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