8,170 research outputs found
Caracterização de latossolo: um estudo prévio para a realização de ensaios de sorção de antimicrobianos promotores do crescimento.
Tail docking in pigs: a review on its short- and long-term consequences and effectiveness in preventing tail biting
In spite of European legislation attempting to limit this practice, tail docking is nowadays the only preventive measure against tail biting which is widely adopted by farmers. Docking consists in amputating, usually without anaesthesia or analgesia, the distal part of the tail, in order to reduce its attractiveness and to sensitize it, increasing avoidance behaviour in the bitten pig. Tail docking results in both acute and chronic effects on pig welfare, and its effectiveness in preventing tail biting is limited, since it reduces the symptoms of a behavioural disorder, but does not address the underlying causes. The aim of the present paper is to review the available literature on the effects of tail docking on swine welfare. Although from a practical standpoint the welfare risks arising from tail docking may appear to be negligible compared to those arising during and after tail biting outbreaks, it should be considered that, apart from acute physiological and behavioural responses, tail docking may also elicit long-term effects on weight gain, tail stump sensitivity and animal freedom to express their normal behaviour. Such chronic effects have been poorly investigated so far. Besides, studies evaluating the effectiveness of anaesthetics or analgesic treatments are often conflicting. Within this framework, further research is recommended in order to reduce the acute and chronic pain and discomfort experienced by the animals, until preventive measures (e.g., environmental enrichment, stocking densities) are broadly adopted to prevent tail biting
Avaliação do grau de humidificação da matéria orgânica de solo irrigado com efluente por espectroscopia de fluorescência na região do UV/Vis e determinação de carbono via úmida.
The GAB2 signaling scaffold promotes anchorage independence and drives a transcriptional response associated with metastatic progression of breast cancer.
Avaliação espectroscópica de ácidos húmicos extraídos de solos sob adição de diferentes compostos orgânicos.
A crescente produção de resíduos agrícolas vem provocando significativos impactos ambientais, pois sua taxa de geração é muito maior do que a sua taxa de degradação. Neste contexto a compostagem mostra-se como uma alternativa de reaproveitamento, reciclagem e redução destes resíduos gerados pelo homem. No processo de compostagem ocorrem reações bioquímicas para a estabilização do material, estando diretamente associadas à humificação da matéria orgânica, sendo as substancias húmicas seu principal componente. O objetivo do estudo foi analisar os ácidos húmicos extraídos de solos sob disposição de distintos compostos orgânicos por Espectroscopia de Infravermelho com Transformada de Fourier (FTIR). Os resultados sugerem possíveis reações químicas decorrentes da aplicação de diferentes compostos no solo.Disponível também em: Cadernos de Agroecologia, V. 5, n.1, 2010
GaAs:Mn nanowires grown by molecular beam epitaxy of (Ga,Mn)As at MnAs segregation conditions
GaAs:Mn nanowires were obtained on GaAs(001) and GaAs(111)B substrates by
molecular beam epitaxial growth of (Ga,Mn)As at conditions leading to MnAs
phase separation. Their density is proportional to the density of catalyzing
MnAs nanoislands, which can be controlled by the Mn flux and/or the substrate
temperature. Being rooted in the ferromagnetic semiconductor (Ga,Mn)As, the
nanowires combine one-dimensional properties with the magnetic properties of
(Ga,Mn)As and provide natural, self assembled structures for nanospintronics.Comment: 13 pages, 6 figure
Estudo do potencial de sequestro de carbono do solo sob a adição de biossólido em cultura de eucalipto grandis utilizando espectroscopia de fluorescência induzida por laser (FIL).
All supersymmetric solutions of minimal supergravity in six dimensions
A general form for all supersymmetric solutions of minimal supergravity in
six dimensions is obtained. Examples of new supersymmetric solutions are
presented. It is proven that the only maximally supersymmetric solutions are
flat space, AdS_3 x S^3 and a plane wave. As an application of the general
solution, it is shown that any supersymmetric solution with a compact horizon
must have near-horizon geometry R^{1,1} x T^4, R^{1,1} x K3 or identified AdS_3
x S^3.Comment: 40 pages. v2: two references adde
Espectroscopia na região do infravermelho próximo (NIRS): uma ferramenta para estimar o teor de carbono em amostras de solo.
Holographic renormalization and supersymmetry
Holographic renormalization is a systematic procedure for regulating
divergences in observables in asymptotically locally AdS spacetimes. For dual
boundary field theories which are supersymmetric it is natural to ask whether
this defines a supersymmetric renormalization scheme. Recent results in
localization have brought this question into sharp focus: rigid supersymmetry
on a curved boundary requires specific geometric structures, and general
arguments imply that BPS observables, such as the partition function, are
invariant under certain deformations of these structures. One can then ask if
the dual holographic observables are similarly invariant. We study this
question in minimal N = 2 gauged supergravity in four and five dimensions. In
four dimensions we show that holographic renormalization precisely reproduces
the expected field theory results. In five dimensions we find that no choice of
standard holographic counterterms is compatible with supersymmetry, which leads
us to introduce novel finite boundary terms. For a class of solutions
satisfying certain topological assumptions we provide some independent tests of
these new boundary terms, in particular showing that they reproduce the
expected VEVs of conserved charges.Comment: 70 pages; corrected typo
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