386 research outputs found
Evaluation of different aspects of maximum entropy for niche-based modeling
AbstractBiodiversity conservation is a world challenge that needs attention and efficient strategies for its success. Modeling of geographic distributions of species is used in assorted applications related to biodiversity conservation. Maximum entropy (maxent) is a technique recently applied to modeling of geographic distributions of species and is being largely used by biologists. The aim is to evaluate different viewpoints of this technique. The first evaluation is concerned with the performance of the algorithm. A parallel version of the maxent-based algorithm available in openModeller is presented. openModeller is a set of tools provided for researchers interested in modeling of geographic distributions of species. The second evaluation is focused on tuning the regularization parameter, since it can severely affect the performance of the algorithm and can take a long time to be adjusted. In addition, the algorithm was evaluated without the use of a regularization parameter and with an adaptive maximum entropy approach. This approach was evaluated as a replacement of the regularization parameter. The validation of the assessments was based on a dataset with 20 species. The results show: an improvement in the algorithm performance using parallelism, considering only the running time; the regularization parameter does not depend on the number of samples, or on the number of iterations in training; species with the same number of samples fit better with different values of the regularization parameter (different magnitude order); the adaptive approach cannot replace the regularization parameter
Hypothalamic Endoplasmic Reticulum Stress Of Overtrained Mice After Recovery
knowing the relationship between endoplasmic reticulum (ER) stress and inflammation and based on the fact that downhill running-based overtraining (OT) model increases hypothalamus levels of some pro-inflammatory cytokines, we verified the effects of three OT protocols on the levels of BiP, pIRE-1 (Ser734), pPERK (Thr981), pelF2alpha (Ser52), ATF-6 and GRP-94 proteins in the mouse hypothalamus after two weeks of recovery. Methods: the mice were randomized into control (CT), overtrained by downhill running (OTR/down), overtrained by uphill running (OTR/up) and overtrained by running without inclination (OTR) groups. After 2-week total recovery period (i.e., week 10), hypothalamus was removed and used for immunoblotting. Results: The OTR/down group exhibited high levels of BiP and ATF6. The other OT protocols showed higher levels of pPERK (Th981) and pelf-2alpha (Ser52) when compared with the CT group. Conclusion: The current results suggest that after a 2-week total recovery period, the overtrained groups increased partially their ER stress protein levels, but without hypothalamic inflammation, which characterizes a physiological condition related to an adaptation mechanism.2
Invariant Natural Killer T-cells and their subtypes may play a role in the pathogenesis of endometriosis
Objective: To evaluate the frequencies of iNKT cells and their subsets in patients with deep endometriosis.
Methods: A case-control study was conducted between 2013 and 2015, with 73 patients distributed into two groups: 47 women with a histological diagnosis of endometriosis and 26 controls. Peripheral blood, endometriosis lesions, and healthy peritoneal samples were collected on the day of surgery to determine the frequencies of iNKT cells and subtypes via flow cytometry analysis.
Results: The authors observed a lower number of iNKT (p = 0.01) and Double-Negative (DN) iNKT cells (p = 0.02) in the blood of patients with endometriosis than in the control group. The number of DN iNKT IL-17+ cells in the secretory phase was lower in the endometriosis group (p = 0.049). There was an increase in the secretion of IL-17 by CD4+ iNKT cells in the blood of patients with endometriosis and severe dysmenorrhea (p = 0.038), and severe acyclic pelvic pain (p = 0.048). Patients with severe dysmenorrhea also had a decreased number of CD4+ CCR7+ cells (p = 0.022).
Conclusion: The decreased number of total iNKT and DN iNKT cells in patients with endometriosis suggests that iNKT cells play a role in the pathogenesis of endometriosis and can be used to develop new diagnostic and therapeutic agents
EstĂmulo no crescimento e na hidrĂłlise de atp em raĂzes de alface tratadas com humatos de vermicomposto: ii - efeito da fonte de vermicomposto.
Um dos fatores mais limitantes para a produção de vermicomposto Ă© a disponibilidade de esterco. Neste trabalho, foi avaliado o efeito da substituição parcial do esterco por bagaço de cana e por resĂduos de leguminosa (Gliricidia sepium) na vermicompostagem sobre a qualidade do vermicomposto e sobre a bioatividade dos humatos, avaliadas por meio da anĂĄlise do crescimento radicular e da atividade das bombas de H+ isoladas de raĂzes de alface. A substituição do esterco por bagaço de cana e por resĂduos de leguminosas nĂŁo acarretou prejuĂzo Ă s caracterĂsticas quĂmicas dos vermicompostos. No entanto, os humatos isolados
dos diferentes vermicompostos apresentaram caracterĂsticas quĂmicas distintas,tais como: acidez e propriedades Ăłticas distintas. Os humatos produzidos a partir de esterco de bovino e da mistura esterco bovino + bagaço proporcionaram maiores estĂmulos no crescimento radicular das plantas de alface, sendo os mais indicados para uso na forma solĂșvel. A inclusĂŁo de resĂduos de leguminosas no processo de vermicompostagem produziu humatos sem efeito sobre o desenvolvimento das raĂzes de alface
Theory and simulation of quantum photovoltaic devices based on the non-equilibrium Green's function formalism
This article reviews the application of the non-equilibrium Green's function
formalism to the simulation of novel photovoltaic devices utilizing quantum
confinement effects in low dimensional absorber structures. It covers
well-known aspects of the fundamental NEGF theory for a system of interacting
electrons, photons and phonons with relevance for the simulation of
optoelectronic devices and introduces at the same time new approaches to the
theoretical description of the elementary processes of photovoltaic device
operation, such as photogeneration via coherent excitonic absorption,
phonon-mediated indirect optical transitions or non-radiative recombination via
defect states. While the description of the theoretical framework is kept as
general as possible, two specific prototypical quantum photovoltaic devices, a
single quantum well photodiode and a silicon-oxide based superlattice absorber,
are used to illustrated the kind of unique insight that numerical simulations
based on the theory are able to provide.Comment: 20 pages, 10 figures; invited review pape
EstĂmulo no crescimento e na hidrĂłlise de ATP em raĂzes de alface tratadas com humatos de vermicomposto: i - efeito da concentração.
O vermicomposto contĂ©m uma concentração elevada de substĂąncias hĂșmicas e jĂĄ Ă© bem conhecido o efeito do seu uso sobre as propriedades do solo. No entanto,a ação direta das substĂąncias hĂșmicas sobre o metabolismo das plantas Ă© menos conhecida. O objetivo deste trabalho foi avaliar o uso de humatos extraĂdos de vermicomposto de esterco de curral com KOH 0,1 mol L-1 sobre o desenvolvimento e metabolismo de ATP em plĂąntulas de alface. ApĂłs a germinação, plĂąntulas de alface foram tratadas com os humatos em concentraçÔes que variaram de 0 a 100 mg L-1 de C, durante quinze dias. Foram avaliados o crescimento da raiz e a atividade das bombas de H+ isoladas da fração microssomal do sistema radicular. Foi observado aumento na matĂ©ria fresca e seca do sistema radicular, bem como no nĂșmero de sĂtios de mitose, raĂzes emergidas do eixo principal, na ĂĄrea e no comprimento radiculares, com o uso do humato na concentração de 25 mg L-1 de C. TambĂ©m foi observado, nessa concentração, aumento significativo na hidrĂłlise de ATP pelas bombas de H+, responsĂĄveis pela geração de energia necessĂĄria Ă absorção de Ăons e pelo crescimento celular
Measurement of the polarisation of W bosons produced with large transverse momentum in pp collisions at sqrt(s) = 7 TeV with the ATLAS experiment
This paper describes an analysis of the angular distribution of W->enu and
W->munu decays, using data from pp collisions at sqrt(s) = 7 TeV recorded with
the ATLAS detector at the LHC in 2010, corresponding to an integrated
luminosity of about 35 pb^-1. Using the decay lepton transverse momentum and
the missing transverse energy, the W decay angular distribution projected onto
the transverse plane is obtained and analysed in terms of helicity fractions
f0, fL and fR over two ranges of W transverse momentum (ptw): 35 < ptw < 50 GeV
and ptw > 50 GeV. Good agreement is found with theoretical predictions. For ptw
> 50 GeV, the values of f0 and fL-fR, averaged over charge and lepton flavour,
are measured to be : f0 = 0.127 +/- 0.030 +/- 0.108 and fL-fR = 0.252 +/- 0.017
+/- 0.030, where the first uncertainties are statistical, and the second
include all systematic effects.Comment: 19 pages plus author list (34 pages total), 9 figures, 11 tables,
revised author list, matches European Journal of Physics C versio
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