63,239 research outputs found
Holographic Superconductors from Einstein-Maxwell-Dilaton Gravity
We construct holographic superconductors from Einstein-Maxwell-dilaton
gravity in 3+1 dimensions with two adjustable couplings and the charge
carried by the scalar field. For the values of and we
consider, there is always a critical temperature at which a second order phase
transition occurs between a hairy black hole and the AdS RN black hole in the
canonical ensemble, which can be identified with the superconducting phase
transition of the dual field theory. We calculate the electric conductivity of
the dual superconductor and find that for the values of and where
is small the dual superconductor has similar properties to the
minimal model, while for the values of and where is
large enough, the electric conductivity of the dual superconductor exhibits
novel properties at low frequencies where it shows a "Drude Peak" in the real
part of the conductivity.Comment: 25 pages, 13 figures; v2, typos corrected; v3, refs added, to appear
in JHE
Pharmacokinetic Studies on Metoprolol - Eudragit Matrix Tablets and Bioequivalence Consideration with MepressorÂź
Purpose: To investigate the pharmacokinetics of of a developed metoprolol and a reference standard (Mepressor®).Methods: Metoprolol tartrate-loaded Eudragit® FS microparticles were formulated and compressed into tablets. The tablets were tested for their physicochemical properties according to United States Pharmacopoeia (USP) criteria. In vivo studies of the formulations were carried out in 28 young healthy fasting male volunteers based on a randomized open label 4×4 crossover study design with a washout period of 7 days.Results: In vitro tests showed that the developed and reference standard of metoprolol tablets met compendia (USP) requirements. Zero order release of drug was observed from all the tablets. In vivo data demonstrated that there were significant (p < 0.05) differences in tmax, Cmax, MRT, AUC0−t, and AUC0–∞ between the reference and test (developed) formulations. However, the 90 % class interval for the mean ratios of the ln-transformed Cmax, AUC0-t and AUC0-α for the reference, T1, T2, and T3 lied in the bioequivalence range (80 to 125 %) indicating bioequivalence between the compared formulations. Conclusion: It can be concluded from this single-dose study that the reference and test (developed) formulations met the predetermined criteria for bioequivalence in young healthy fasting male human subjects as the bioequivalence factor lie in the pre-determined limits for bioequivalence. Thus, the two formulations can be considered bioequivalent.Keywords: Metoprolol tartrate, Eudragit® FS, Microparticles, Bioavailability, Pharmacokinetics
Cordyla pinnata améliore les propriétés du sol et la productivité des cultures
Dans les systèmes agroforestiers, les cultures sous le couvert des arbres (SC) bénéficient de plus de nutriments, après décomposition et minéralisation des litières, que celles hors de leur couvert (HC). La fertilité des sols et la productivité du mil et de l’arachide ont été évaluées sur des sols prélevés à différentes distances de Cordyla pinnata, une légumineuse arborée qui forme un parc agroforestier au Sénégal. Les analyses de sols ont montré des valeurs plus élevées pour N total, Ca échangeable et CEC sous le couvert de l’espèce. Pour le mil, la hauteur, les biomasses aérienne et racinaire ont également été plus élevées sur les sols SC. Par conséquent, la biomasse totale du mil a fortement augmenté (+ 90%) sur les sols SC. Pour l’arachide, la longueur totale, les biomasses (tiges, feuilles, gousses, racines) ont été supérieures sur les sols SC. Comme pour le mil, la biomasse totale de l’arachide a augmenté (+ 94%) sur les sols SC par rapport au découvert. La plupart des variables des cultures ont été plus élevées sur les sols SC, probablement à cause de leur meilleur statut nutritif. L’introduction des arbres dans les systèmes de production au Sahel pourrait ainsi constituer une bonne stratégie pour améliorer la fertilité des sols et contribuer au développement d’une agriculture durable.Mots clés: Arachide, Fertilité des sols, Mil, Parc agroforestier, Sénéga
Plasticity facilitates sustainable growth in the commons
In the commons, communities whose growth depends on public goods, individuals
often rely on surprisingly simple strategies, or heuristics, to decide whether
to contribute to the common good (at risk of exploitation by free-riders).
Although this appears a limitation, here we show how four heuristics lead to
sustainable growth by exploiting specific environmental constraints. The two
simplest ones --contribute permanently or switch stochastically between
contributing or not-- are first shown to bring sustainability when the public
good efficiently promotes growth. If efficiency declines and the commons is
structured in small groups, the most effective strategy resides in contributing
only when a majority of individuals are also contributors. In contrast, when
group size becomes large, the most effective behavior follows a minimal-effort
rule: contribute only when it is strictly necessary. Both plastic strategies
are observed in natural systems what presents them as fundamental social motifs
to successfully manage sustainability
Eficiencia comparativa dos tratamentos intra-uterinos para endometrite bovina.
bitstream/item/143037/1/2057.pd
Deformation of Codimension-2 Surface and Horizon Thermodynamics
The deformation equation of a spacelike submanifold with an arbitrary
codimension is given by a general construction without using local frames. In
the case of codimension-1, this equation reduces to the evolution equation of
the extrinsic curvature of a spacelike hypersurface. In the more interesting
case of codimension-2, after selecting a local null frame, this deformation
equation reduces to the well known (cross) focusing equations. We show how the
thermodynamics of trapping horizons is related to these deformation equations
in two different formalisms: with and without introducing quasilocal energy. In
the formalism with the quasilocal energy, the Hawking mass in four dimension is
generalized to higher dimension, and it is found that the deformation of this
energy inside a marginal surface can be also decomposed into the contributions
from matter fields and gravitational radiation as in the four dimension. In the
formalism without the quasilocal energy, we generalize the definition of slowly
evolving future outer trapping horizons proposed by Booth to past trapping
horizons. The dynamics of the trapping horizons in FLRW universe is given as an
example. Especially, the slowly evolving past trapping horizon in the FLRW
universe has close relation to the scenario of slow-roll inflation. Up to the
second order of the slowly evolving parameter in this generalization, the
temperature (surface gravity) associated with the slowly evolving trapping
horizon in the FLRW universe is essentially the same as the one defined by
using the quasilocal energy.Comment: Latex, 61 pages, no figures; v2, type errors corrected; v3,
references and comments are added, English is improved, to appear in JHE
Metodologia de criação do percevejo bronzeado Thaumastocoris peregrinus (Hemiptera: Thaumastocoridae) em condição controlada de quarentena.
Cytotoxic activity of fungal metabolites from the Pathogenic Fungus Beauveria bassiana: an intraspecific evaluation of beauvericin production.
A matter of words: NLP for quality evaluation of Wikipedia medical articles
Automatic quality evaluation of Web information is a task with many fields of
applications and of great relevance, especially in critical domains like the
medical one. We move from the intuition that the quality of content of medical
Web documents is affected by features related with the specific domain. First,
the usage of a specific vocabulary (Domain Informativeness); then, the adoption
of specific codes (like those used in the infoboxes of Wikipedia articles) and
the type of document (e.g., historical and technical ones). In this paper, we
propose to leverage specific domain features to improve the results of the
evaluation of Wikipedia medical articles. In particular, we evaluate the
articles adopting an "actionable" model, whose features are related to the
content of the articles, so that the model can also directly suggest strategies
for improving a given article quality. We rely on Natural Language Processing
(NLP) and dictionaries-based techniques in order to extract the bio-medical
concepts in a text. We prove the effectiveness of our approach by classifying
the medical articles of the Wikipedia Medicine Portal, which have been
previously manually labeled by the Wiki Project team. The results of our
experiments confirm that, by considering domain-oriented features, it is
possible to obtain sensible improvements with respect to existing solutions,
mainly for those articles that other approaches have less correctly classified.
Other than being interesting by their own, the results call for further
research in the area of domain specific features suitable for Web data quality
assessment
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