1,033 research outputs found
Kepler Exoplanet Candidate Host Stars are Preferentially Metal Rich
We find that Kepler exoplanet candidate (EC) host stars are preferentially
metal-rich, including the low-mass stellar hosts of small-radius ECs. The last
observation confirms a tentative hint that there is a correlation between the
metallicity of low-mass stars and the presence of low-mass and small-radius
exoplanets. In particular, we compare the J-H--g-r color-color distribution of
Kepler EC host stars with a control sample of dwarf stars selected from the
~150,000 stars observed during Q1 and Q2 of the Kepler mission but with no
detected planets. We find that at J-H = 0.30 characteristic of solar-type
stars, the average g-r color of stars that host giant ECs is 4-sigma redder
than the average color of the stars in the control sample. At the same time,
the average g-r color of solar-type stars that host small-radius ECs is
indistinguishable from the average color of the stars in the control sample. In
addition, we find that at J-H = 0.62 indicative of late K dwarfs, the average
g-r color of stars that host small-radius ECs is 4-sigma redder than the
average color of the stars in the control sample. These offsets are unlikely to
be caused by differential reddening, age differences between the two
populations, or the presence of giant stars in the control sample. Stellar
models suggest that the first color offset is due to a 0.2 dex enhancement in
[Fe/H] of the giant EC host population at M_star = 1 M_Sun, while Sloan
photometry of M 67 and NGC 6791 suggests that the second color offset is due to
a similar [Fe/H] enhancement of the small-radius EC host population at M_star =
0.7 M_Sun. These correlations are a natural consequence of the core-accretion
model of planet formation.Comment: 15 pages, 8 figures, and 1 table in emulateapj format; accepted for
publication in Ap
Adaptive Optics Images of Kepler Objects of Interest
All transiting planets are at risk of contamination by blends with nearby,
unresolved stars. Blends dilute the transit signal, causing the planet to
appear smaller than it really is, or produce a false positive detection when
the target star is blended with eclipsing binary stars. This paper reports on
high spatial-resolution adaptive optics images of 90 Kepler planetary
candidates. Companion stars are detected as close as 0.1 arcsec from the target
star. Images were taken in the near-infrared (J and Ks bands) with ARIES on the
MMT and PHARO on the Palomar Hale 200-inch. Most objects (60%) have at least
one star within 6 arcsec separation and a magnitude difference of 9. Eighteen
objects (20%) have at least one companion within 2 arcsec of the target star; 6
companions (7%) are closer than 0.5 arcsec. Most of these companions were
previously unknown, and the associated planetary candidates should receive
additional scrutiny. Limits are placed on the presence of additional companions
for every system observed, which can be used to validate planets statistically
using the BLENDER method. Validation is particularly critical for low-mass,
potentially Earth-like worlds, which are not detectable with current-generation
radial velocity techniques. High-resolution images are thus a crucial component
of any transit follow-up program.Comment: 9 pages, 4 figures, accepted to A
Accretion-Induced Lithium Line Enhancements in Classical T Tauri Stars: RW Aur
It is widely accepted that much of the stochastic variability of T Tauri
stars is due to accretion by a circumstellar disk. The emission line spectrum
as well as the excess continuum emission are common probes of this process. In
this communication, we present additional probes of the circumstellar
environment in the form of resonance lines of low ionization potential
elements. Using a set of 14 high resolution echelle observations of the
classical T Tauri star (CTTS), RW Aur, taken between 1986 and 1996, we
carefully measure the continuum veiling at each epoch by comparing more than
500 absorption lines with those of an appropriate template. This allows us to
accurately subtract out the continuum emission and to recover the underlying
photospheric spectrum. In doing so, we find that selected photospheric lines
are enhanced by the accretion process, namely the resonance lines of LiI and
KI. A resonance line of TiI and a low excitation potential line of CaI also
show weak enhancements. Simple slab models and computed line bisectors lead us
to propose that these line enhancements are markers of cool gas at the
beginning of the accretion flow which provides an additional source of line
opacity. These results suggest that published values of surface lithium
abundances of classical T Tauri stars are likely to be overestimated. This
would account for the various reports of surface lithium abundances in excess
of meteoritic values among the extreme CTTS. Computing LTE lithium abundances
of RW Aur in a low and then high accretion state yields abundances which vary
by one order of magnitude. The low accretion state lithium abundance is
consistent with theoretical predictions for a star of this age and mass while
the high accretion state spectrum yields a super-meteoritic lithium abundance.Comment: 28 pages, 8 figures, accepted by Ap
Uso de ninhos de cupin como fonte de matéria orgânica em sistemas de produção agrosilviculturais na Amazônia
The growth of two annual crops, okra (Abelmoschus escutentus) and egg-plant (Solatium melongena) and one perennial crop, andiroba (Carapa guianensis, a native forest tree of Amazonia) under different treatments with organic manure derived from termite nest material of wood-feeding Nasutitermes species was tested (randomized block design). The use of 25-100 g of nest material gave no significant increase in okra productivity, and 25-200 g gave no significant response in andiroba. The combined use of NPK with 200 g of nest material gave a significant higher production in egg-plant (total number and total fresh weight of fruits) when compared to the control (without fertilizer) and to the treatment with NPK only.The results suggest the possibility to use termite nest material to enhance crop production in Amazonia, particularly in combination with low amounts of mineral fertilizer. Research lines for further investigations are outlined.Foi avaliado crescimento de duas espécies agriculturais anuais, quiabo (Abelmoschus esculentus) e berinjela (Solatium melongena), e de uma espécie perene, andiroba (Carapa guianensis, uma árvore nativa da Amazônia) sob diferentes tratamentos com matéria orgânica derivada de material de cupinzeiro de espécies xilófagas de Nasutitermes (desenho de bloco randomizado). O uso de 25-100 g de material de termiteiro não levou a um incremento significativo da produtividade em quiabo, e 25-200 g não resultou numa resposta significativa em andiroba. O uso combinado de NPK com 200 g de ninho de cupim resultou numa produção significantemente maior em S. melongena (número total e peso fresco total de frutos) se comparado com o controle (sem fertilizante nenhum) e com o tratamento de NPK apenas. Os resultados sugerem a possibilidade de usar material de cupinzeiro para melhorara produção agrossilvicultural na Amazônia, especialmente em combinação com pequenas quantidades de fertilizante mineral Linhas de pesquisa para futuras investigações são apresentadas
Evaluation of Microencapsulation of The UFV-AREG1 Bacteriophage in Alginate-Ca Microcapsules using Microfluidic Devices
The indiscriminate use of antibiotics and the emergence of resistant
microorganisms have become a major challenge for the food industry. The purpose
of this work was to microencapsulate the bacteriophage UFV-AREG1 in a calcium
alginate matrix using microfluidic devices and to study the viability and
efficiency of retention. The microcapsules were added to gel of propylene
glycol for use as an antimicrobial in the food industry. The technique showed
the number of the phage encapsulation, yielding drops with an average 100-250
m of diameter, 82.1 2% retention efficiency and stability in the gel
matrix for 21 days. The gel added to the microencapsulated phage showed
efficiency (not detectable on the surface) in reducing bacterial contamination
on the surface at a similar level to antimicrobial chemicals (alcohol 70%).
Therefore, it was possible to microencapsulate bacteriophages in alginate-Ca
and apply the microcapsules in gels for use as sanitizers in the food industry.Comment: 8 pages, 5 figure
Isokinetics strength relation with fear of fall, falls and physical activity level in elderly women
Introduction: Low levels of physical activity (PA) in elderly has been related with the decline in physical and psychological functions, affecting the ability in the performance of activities of daily living (ADLs) and contributing to the occurrence of walking-related fall (Metz, Lee, Sui, Powell, Blair, 2010). The purpose of this study was to relate strength levels with fear of fall (FF), falls occurrence as well as with PA level on elderly women.
Methods: One hundred not institutionalized post-menopausal women (aged 66.17 ± 8.21 years) volunteered to participate on this research. The peak torque (PT) at 60º.s-1 ( 3 rep) and 180º.s-1 (20 rep) angular speeds in knee extension and flexion concentric actions were measured using an isokinetic dynamometer (Biodex System 3). Muscular fatigue was also estimated at 180º.s-1. To achieve the occurrence of falls during last year as well FF score, we applied a standardized Questionnaire that included socio-demographic, health and falls parameters. PA level was accessed by interview with Yale Physical Activity Questionnaire.
Descriptive statistics was performed using means and standard deviations. The Spearman correlation coefficient was used to investigate associations among quantitative independent variables.
Results: PT at 60º.s-1 in knee extension and flexion and PT at 180º.s-1 in knee flexion showed a positive association with vigorous index (r=,205 p=,041; r=,249 p=,013; r=,218 p=,029 respectively). Standing index presented also a positive correlation with PT at 60º.s-1 and PT 180º.s-1 in knee extension (r=,205 p=,041 and r=,314 p=,004).
FF registered a positive association with body mass (BM) and body mass index (BMI) (r=,205 p=,041 and r=,201 p=,045), and a negative association with PT in extension action on both angular velocities (r=-,241 p=,016 and r=-,203 p=,043).
Muscular fatigue showed a positive correlation with the number of falls during the last year (r=,201 p=,036).
Conclusions: Decreases of strength on lower limb is an important factor that contributes to falls occurrence once we registered a negative relation between PT on extension action and the FF.
Our data related higher values of BM and BMI with higher fear of falling confirming that overweight are common associated to disturb on gait function and mobility that represents also a risk factor for falls.
Present results suggest that more time of PA is needed to increase lower limb strength in the elderly
Efeito de um treino de força em seco no desempenho em jovens nadadores
Em natação a performance depende da força e potência muscular (Newton et al., 2002)
e a capacidade de exercer força na água é fundamental, especialmente em distâncias
curtas (Morouço et al., 2011). Assim, os programas de treino de força em seco são
comuns em natação ainda que o consenso sobre os benefícios específicos para o
nadador ainda não tenha sido alcançado (Tanaka et al., 1993; Trappe and Pearson, 1994;
Girold et al., 2007). Por um lado, várias investigações apresentaram melhorias na
performance de nado após um programa de treino de força em seco (Strass, 1988;
Girold et al., 2007; Aspenes et al., 2009; Girold et al., 2012). Por outro lado, várias
investigações não apresentaram melhorias na performance de nado após um programa
de treino de força em seco (Tanaka et al., 1993; Trappe and Pearson, 1994; Garrido et
al., 2010; Sadowski et al., 2012). As razões para os resultados menos positivos podem
dever-se a falhas nos protocolos de intervenção, tais como: especificidade do meio
aquático (incapacidade de replicar os movimentos aquáticos em meio terrestre e a falta
da resistência da água); escolha de exercícios pouco específicos ou que não solicitem os
mesmos grupos musculares que o nado; velocidade de execução e cargas dos exercícios;
amostra e os momentos das avaliações. As investigações com jovens nadadores são
ainda mais escassas do que com adultos, o que revela alguma necessidade de
investigação em torno deste assunto.
Assim, os objetivos deste estudo foram examinar os efeitos de um programa de treino
de força em seco: (i) na performance de nado e (ii) produção de força na água
Accidents in Children and Adolescents: What Context and What Approach? A Nine-Month Experience at the Emergency Department of a Level II Hospital
Introdução: Os acidentes constituem uma importante causa de morbimortalidade infantil e de recurso ao serviço de urgência pediátrica. A nível nacional conhecem-se apenas alguns dados epidemiológicos.
Métodos: Estudo observacional transversal com análise da coorte das crianças observadas no serviço de urgência pediátrica de um hospital nível II por motivo de acidente, durante um período de nove meses, com dados obtidos através de um inquérito e submetidos a análise estatística.
Resultados: Das 22502 admissões de crianças até aos 14 anos registadas, 1746 (7,8%) foram por acidentes. A maioria era do sexo masculino e tinha mais de 5 anos. Os acidentes ocorreram maioritariamente no exterior da escola (29,1%) e interior de casa (25%), predominando a queda como tipo de acidente (55,5%) e a contusão como mecanismo de lesão (54,2%). A maioria das crianças (77,3%) foi submetida a exames complementares de diagnóstico destacando-se os radiológicos. Os diagnósticos
mais frequentes foram os traumatismos superficiais (47,9%) e os ferimentos (24,8%). Em 6,6% (115) dos casos os acidentes foram considerados graves. Estas admissões por acidentes associaram-se a uma despesa imediata estimada de 124 mil euros.
Discussão: A frequência elevada e o local de ocorrência dos acidentes coincidiram com a literatura. Apesar do predomínio das lesões minor superficiais (47,9%) verificou-se um número significativo de crianças com necessidade de cuidados hospitalares. Não foram registados óbitos. Os autores concluem que os acidentes em crianças foram um motivo frequente de ida ao serviço de urgência pediátrica com importante consumo de recursos. A sensibilização dos cuidadores é essencial na prevenção dos acidentes
In situ magnetic separation of antibody fragments from Escherichia coli in complex media.
BACKGROUND: In situ magnetic separation (ISMS) has emerged as a powerful tool to overcome process constraints such as product degradation or inhibition of target production. In the present work, an integrated ISMS process was established for the production of his-tagged single chain fragment variable (scFv) D1.3 antibodies ("D1.3") produced by E. coli in complex media. This study investigates the impact of ISMS on the overall product yield as well as its biocompatibility with the bioprocess when metal-chelate and triazine-functionalized magnetic beads were used. RESULTS: Both particle systems are well suited for separation of D1.3 during cultivation. While the triazine beads did not negatively impact the bioprocess, the application of metal-chelate particles caused leakage of divalent copper ions in the medium. After the ISMS step, elevated copper concentrations above 120 mg/L in the medium negatively influenced D1.3 production. Due to the stable nature of the model protein scFv D1.3 in the biosuspension, the application of ISMS could not increase the overall D1.3 yield as was shown by simulation and experiments. CONCLUSIONS: We could demonstrate that triazine-functionalized beads are a suitable low-cost alternative to selectively adsorb D1.3 fragments, and measured maximum loads of 0.08 g D1.3 per g of beads. Although copper-loaded metal-chelate beads did adsorb his-tagged D1.3 well during cultivation, this particle system must be optimized by minimizing metal leakage from the beads in order to avoid negative inhibitory effects on growth of the microorganisms and target production. Hereby, other types of metal chelate complexes should be tested to demonstrate biocompatibility. Such optimized particle systems can be regarded as ISMS platform technology, especially for the production of antibodies and their fragments with low stability in the medium. The proposed model can be applied to design future ISMS experiments in order to maximize the overall product yield while the amount of particles being used is minimized as well as the number of required ISMS steps
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