2,456 research outputs found
A large sample of calibration stars for Gaia: log g from Kepler and CoRoT
Asteroseismic data can be used to determine surface gravities with precisions
of < 0.05 dex by using the global seismic quantities Deltanu and nu_max along
with Teff and [Fe/H]. Surface gravity is also one of the four stellar
properties to be derived by automatic analyses for 1 billion stars from Gaia
data (workpackage GSP_Phot). We explore seismic data from MS F, G, K stars
(solar-like stars) observed by Kepler as a potential calibration source for
methods that Gaia will use for object characterisation (log g). We calculate
log g for bright nearby stars for which radii and masses are known, and using
their global seismic quantities in a grid-based method, we determine an
asteroseismic log g to within 0.01 dex of the direct calculation, thus
validating the accuracy of our method. We find that errors in Teff and mainly
[Fe/H] can cause systematic errors of 0.02 dex. We then apply our method to a
list of 40 stars to deliver precise values of surface gravity, i.e. sigma <
0.02 dex, and we find agreement with recent literature values. Finally, we
explore the precision we expect in a sample of 400+ Kepler stars which have
their global seismic quantities measured. We find a mean uncertainty
(precision) on the order of <0.02 dex in log g over the full explored range 3.8
< log g < 4.6, with the mean value varying only with stellar magnitude (0.01 -
0.02 dex). We study sources of systematic errors in log g and find possible
biases on the order of 0.04 dex, independent of log g and magnitude, which
accounts for errors in the Teff and [Fe/H] measurements, as well as from using
a different grid-based method. We conclude that Kepler stars provide a wealth
of reliable information that can help to calibrate methods that Gaia will use,
in particular, for source characterisation with GSP_Phot where excellent
precision (small uncertainties) and accuracy in log g is obtained from seismic
data.Comment: Accepted MNRAS, 15 pages (10 figures and 3 tables), v2=some rewording
of two sentence
Produtividade e tempo de cocção de grãos de feijão-caupi de porte ereto e semiereto cultivados em Dourados, MS, ano 2011.
A indicação de cultivares de feijão-caupi com altas produtividades e de cozimento rápido proporciona estabilidade ao agricultor e economia de tempo no cozimento. Este trabalho teve como objetivo avaliar 20 genótipos de feijão-caupi de porte ereto e semi-ereto e identificar genótipos com melhor desempenho produtivo e menor tempo de cozimento para o cultivo na região de Dourados, MS. O delineamento experimental foi em blocos casualizados, com quatro repetições. Avaliou-se o período da emergência ao florescimento (DEF), a massa de cem grãos (MCG), a produtividade de grãos secos (PROD) e o tempo de cocção de grãos secos. A cultivar BRS Tumucumaque destacou-se para menor tempo de cozimento e produtividade de grãos e pode ser indicada para cultivo na região de Dourados, MS. As cultivares BRS Caumé e BRS Itaim destacaram-se para precocidade. A maioria dos genótipos apresentou tempo de cozimento abaixo de 26 minutos. A linhagem MCO2-675F-9-3 reuniu maior associação entre tamanho grande do grão e baixo tempo de cozimento. As linhagens MCO3-737F-5-4, MCO3-737F-5-9 e MCO3-737F-5-10 reuniram maior associação entre precocidade e baixo tempo de cozimento.CONAC 2012. Disponível em: http://www.conac2012.org/resumos/pdf/050f.pdf. Acesso em: 03 jul. 2013
Período de convivência das plantas daninhas com cultivares de feijão-caupi em várzea no Amazonas.
Este trabalho teve o objetivo de determinar o período de convivência das plantas daninhas com três cultivares de feijão-caupi (Vigna unguiculata) em solo de várzea no Estado do Amazonas. A semeadura do feijão-caupi foi em outubro de 2007 no sistema convencional
Rooting Pattern Distribution and Spatial Variability of Italian Ryegrass (Lolium Multiflorum Lam) in a Mediterranean Region
It is estimated that less than 10% of the studies on pastures and forages have evaluated the subterranean biomass production. The objective of this study was to evaluate for a Mediterranean region the rooting characteristics and spatial variability of Italian ryegrass (Lolium multiflorum Lam) under two different soil water status conditions
Trend-based analysis of a population model of the AKAP scaffold protein
We formalise a continuous-time Markov chain with multi-dimensional discrete state space model of the AKAP scaffold protein as a crosstalk mediator between two biochemical signalling pathways. The analysis by temporal properties of the AKAP model requires reasoning about whether the counts of individuals of the same type (species) are increasing or decreasing. For this purpose we propose the concept of stochastic trends based on formulating the probabilities of transitions that increase (resp. decrease) the counts of individuals of the same type, and express these probabilities as formulae such that the state space of the model is not altered. We define a number of stochastic trend formulae (e.g. weakly increasing, strictly increasing, weakly decreasing, etc.) and use them to extend the set of state formulae of Continuous Stochastic Logic. We show how stochastic trends can be implemented in a guarded-command style specification language for transition systems. We illustrate the application of stochastic trends with numerous small examples and then we analyse the AKAP model in order to characterise and show causality and pulsating behaviours in this biochemical system
Safety and effectiveness of Copaiba Oleoresin (C. reticulata Ducke) on inflammation and tissue repair of oral wounds in rats.
In traditional communities of the Brazilian Amazon, the copaiba oleoresin (C. reticulata Ducke) is widely known for its therapeutic activity, especially its wound healing and anti-inflammatory actions. Our study aimed to evaluate these effects in oral lesions and the safety of the dosage proposed. A punch biopsy wound was induced on the ventral surface of the tongue of forty-five male Wistar rats under anesthesia. Animals were randomly allocated to one of three groups based on the treatment: control, corticoid and copaiba. A daily dose of each treatment and vehicle was administrated by oral gavage for three consecutive days. Sample collections took place on the third, seventh and 15th days post-wounding for clinical and histopathological analyses. Blood was collected on the third and seventh days for kidneys and liver function tests. Semi-quantitative analyses were performed based on scores of inflammation and reepithelization. Tissue collagen deposition was detected by PicroSirius red staining. Copaiba-treated wounds revealed a smaller wound area, decreased of acute inflammatory reaction and enhanced reepithelization. The levels of kidney and liver function tests did not reveal presence of damage post-treatments. Our findings suggest that copaiba oleoresin is a safe and effective alternative therapy for inflammation and tissue repair of oral wounds in this animal model
Dynamics of levitated nanospheres: towards the strong coupling regime
The use of levitated nanospheres represents a new paradigm for the
optomechanical cooling of a small mechanical oscillator, with the prospect of
realising quantum oscillators with unprecedentedly high quality factors. We
investigate the dynamics of this system, especially in the so-called
self-trapping regimes, where one or more optical fields simultaneously trap and
cool the mechanical oscillator. The determining characteristic of this regime
is that both the mechanical frequency and single-photon
optomechanical coupling strength parameters are a function of the optical
field intensities, in contrast to usual set-ups where and are
constant for the given system. We also measure the characteristic transverse
and axial trapping frequencies of different sized silica nanospheres in a
simple optical standing wave potential, for spheres of radii \,nm,
illustrating a protocol for loading single nanospheres into a standing wave
optical trap that would be formed by an optical cavity. We use this data to
confirm the dependence of the effective optomechanical coupling strength on
sphere radius for levitated nanospheres in an optical cavity and discuss the
prospects for reaching regimes of strong light-matter coupling. Theoretical
semiclassical and quantum displacement noise spectra show that for larger
nanospheres with \,nm a range of interesting and novel dynamical
regimes can be accessed. These include simultaneous hybridization of the two
optical modes with the mechanical modes and parameter regimes where the system
is bistable. We show that here, in contrast to typical single-optical mode
optomechanical systems, bistabilities are independent of intracavity intensity
and can occur for very weak laser driving amplitudes
Fermion-Boson Interactions and Quantum Algebras
Quantum Algebras (q-algebras) are used to describe interactions between
fermions and bosons. Particularly, the concept of a su_q(2) dynamical symmetry
is invoked in order to reproduce the ground state properties of systems of
fermions and bosons interacting via schematic forces. The structure of the
proposed su_q(2) Hamiltonians, and the meaning of the corresponding deformation
parameters, are discussed.Comment: 20 pages, 10 figures. Physical Review C (in press
Haemonchus contortus control and performance of dairy goats vaccinated with Barbervax®: preliminary data.
The search for vaccines against worm parasites has been carried out for many decades but it?s especially important now that drench resistance compromised present control methods. Here we present preliminary results of a trial designed to evaluate Barbervax®, a vaccine derived from gut proteins of H. contortus in the control of this nematode in dairy goats. Female Saanen (n=20) and Anglo Nubian (n=20) goats aged six months were assigned by breed, body weight and fecal egg counts into four experimental groups (n=10) vaccinated or not, starting with three priming doses 21 days apart followed by boosts every 6 weeks. All animals grazed on the same bushland area and were subjected to natural plus artificial worm infection. Over the pregnancy and lactation we monitored FAMACHA©, egg counts, blood values and overall performance. Vaccinates of either breed had significant reductions in egg counts compared to controls, with 65.3% ± 10.7 for the Anglo Nubians and 67.6% ± 8.9 for Saanen but blood parameters and FAMACHA scores were positively affected by the vaccine only in the Saanens. Protection was maintained during per partum and lactation. Milk yield and other performance parameters were not affected by the vaccination regimen. Unlike anthelmintics, Barbervax® does not have a withdrawal period and so it could be useful in the management of Haemonchus infection during milk production.In conjunction with 53rd MSPTM Annual Conference
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