4,592 research outputs found
A new analysis of the GJ581 extrasolar planetary system
We have done a new analysis of the available observations for the GJ581
exoplanetary system. Today this system is controversial due to choices that can
be done in the orbital determination. The main ones are the ocurrence of
aliases and the additional bodies - the planets f and g - announced in Vogt et
al. 2010. Any dynamical study of exoplanets requires the good knowledge of the
orbital elements and the investigations involving the planet g are particularly
interesting, since this body would lie in the Habitable Zone (HZ) of the star
GJ581. This region,for this system, is very attractive of the dynamical point
of view due to several resonances of two and three bodies present there. In
this work, we investigate the conditions under which the planet g may exist. We
stress the fact that the planet g is intimately related with the orbital
elements of the planet d; more precisely, we conclude that it is not possible
to disconnect its existence from the determination of the eccentricity of the
planet d. Concerning the planet f, we have found one solution with period
days, but we are judicious about any affirmation concernig this
body because its signal is in the threshold of detection and the high period is
in a spectral region where the ocorruence of aliases is very common. Besides,
we outline some dynamical features of the habitable zone with the dynamical map
and point out the role played by some resonances laying there.Comment: 12 pages, 9 figure
Design and construction of a low-cost remotely piloted aircraft for precision agriculture applications
ArticleThis study aimed to construct a low cost RPA capable of recording georeferenced
images. For the construction of the prototype of a quadcopter type RPA, only essential materials
were used to allow stable flight. A maximum total weight of 2 kg was stipulated, including frame
weight, electronic components, motors and cameras. The aircraft was programmed using a
low-cost microcontroller widely used in prototyping and automation research. An electronic
circuit board is designed to facilitate the connection of the microcontroller with the other
components of the design. Specific software was used for flight control. The prototype was built
successfully, being able to lift stable and controllable flight. However, we still need to acquire
equipment and programming components capable of enabling autonomous images and flights.
The final cost of the RPA was on average 772.81 to $ 1,288.00
Espacialização da soja nos biomas Amazônia, Cerrado, Mata Atlântica e Pampa entre os anos de 2007 e 2012.
Uma das culturas agrícolas que está em maior ascensão no Brasil nas últimas três décadas é a soja, que ocupa 49% da área plantada de grãos no país. A soja é cultivada principalmente nas regiões Sul e Centro-Oeste. A pesquisa feita objetivou demonstrar a distribuição espacial da produção de soja no Brasil em quatro biomas, Amazônia, Cerrado, Mata Atlântica e Pampa, nos anos de 2007 a 2012. A análise de cluster revelou as similaridades entre os biomas Amazônia e Cerrado quanto à produtividade média anual (kg/ha/ano). Os biomas Amazônia e Pampa apresentaram similaridades quanto à área plantada (ha). Mato Grosso, inserido nos biomas Amazônia e Cerrado, foi o estado que apresentou os maiores valores de produção média total e área média plantada
Experimental Observation of Quantum Correlations in Modular Variables
We experimentally detect entanglement in modular position and momentum
variables of photon pairs which have passed through -slit apertures. We
first employ an entanglement criteria recently proposed in [Phys. Rev. Lett.
{\bf 106}, 210501 (2011)], using variances of the modular variables. We then
propose an entanglement witness for modular variables based on the Shannon
entropy, and test it experimentally. Finally, we derive criteria for
Einstein-Podolsky-Rosen-Steering correlations using variances and entropy
functions. In both cases, the entropic criteria are more successful at
identifying quantum correlations in our data.Comment: 7 pages, 4 figures, comments welcom
Behavioural and physiological responses of rabbits
ArticleThe profitability of a rabbit farming system must consider the thermal environment
that the animal will be exposed during the productive period. The goal of this study was to
evaluate the physiological responses and behaviours of 26 New Zealand rabbits during seven
days of their lives at three times a day. The experiment was carried out in rabbit house in the
Federal University of Lavras at Lavras, Brazil. To characterize the thermal environment sensors
were used to measure the dry bulb temperature and relative humidity at 48 points inside the rabbit
house, at 6:00 a.m., 12:00 a.m. and 6:00 p.m. In addition, the temperature and humidity index
(THI) was calculated. The respiratory rate and the superficial temperature of the rabbits' ears were
measured. Behaviour evaluations were monitored in punctual record, with duration of two
min/cage. Later an ethogram was made with the main behaviours identified. Similar data of
behaviour and data of physiological responses were identified by using Ward’s method of cluster
analysis. It was observed the period of 6 a.m. showed more comfortable conditions of THI values
than the others analysed. Besides, physiological responses presented better values at 6:00 a.m. in
comparison to 12:00 and 6:00 p.m. Furthermore, in general, a similar behaviour was observed in
the rabbits at 12:00 and 6:00 p.m., while at 6:00 a.m. was different. But rabbits demonstrated to
be more comfortable at 6 a.m. maybe because at this time environment conditions were better
than the rest of the day. Besides, it can be observed that rabbits were more active in sunrise and
sunset than in the rest of the day
Geostatistics applied to evaluation of thermal conditions and noise in compost dairy barns with different ventilation systems
ArticleThe objective of this work was to evaluate the spatial distribution of thermal
conditions and bed variables in compost dairy barns with different ventilation systems, through
the technique of geostatistics. The experiment was conducted in April 2017, in farms located in
Madre de Deus, Minas Gerais, Brazil. Three facilities were evaluated with different ventilation
systems: natural (NV); mechanical of low volume and high speed (LVHS); and mechanical of
high volume and low speed (HVLS). The interior of the premises was divided into 40 meshes
equidistant points, in which air temperature, relative humidity and air speed were manually
collected. Geostatistics technique was used to assess the spatial dependence of the variables.
The results showed the occurrence of dependence and spatial variability of the variables
evaluated. Based on thermal comfort indexes, it was concluded that dairy cows were under
stress conditions during the hottest hours of the day in the three animal facilities evaluated. The
results obtained allow us to understand that the thermal environment is more influenced by the
ventilation system adopted
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