897 research outputs found
Unique somato-dendritic distribution pattern of Kv4.2 channels on hippocampal CA1 pyramidal cells
A-type K(+) current (I(A) ) plays a critical role in controlling the excitability of pyramidal cell (PC) dendrites. In vitro dendritic patch-pipette recordings have demonstrated a prominent, sixfold increase in I(A) density along the main apical dendrites of rat hippocampal CA1 PCs. In these cells, I(A) is mediated by Kv4.2 subunits, whose precise subcellular distribution and densities in small-diameter oblique dendrites and dendritic spines are still unknown. Here we examined the densities of the Kv4.2 subunit in 13 axo-somato-dendritic compartments of CA1 PCs using a highly sensitive, high-resolution quantitative immunogold localization method (sodium dodecyl sulphate-digested freeze-fracture replica-labelling). Only an approximately 70% increase in Kv4.2 immunogold density was observed along the proximo-distal axis of main apical dendrites in the stratum radiatum with a slight decrease in density in stratum lacunosum-moleculare. A similar pattern was detected for all dendritic compartments, including main apical dendrites, small-diameter oblique dendrites and dendritic spines. The specificity of the somato-dendritic labelling was confirmed in Kv4.2(-/-) tissue. No specific immunolabelling for the Kv4.2 subunit was found in SNAP-25-containing presynaptic axons. Our results demonstrate a novel distribution pattern of a voltage-gated ion channel along the somato-dendritic surface of CA1 PCs, and suggest that the increase in the I(A) along the proximo-distal axis of PC dendrites cannot be solely explained by a corresponding increase in Kv4.2 channel number
Dipolar-controlled spin tunneling and relaxation in molecular magnets
Spin tunneling in molecular magnets controlled by dipole-dipole interactions
(DDI) in the disordered state has been considered numerically on the basis of
the microscopic model using the quantum mean-field approximation. In the actual
case of a strong DDI spin coherence is completely lost and there is a slow
relaxation of magnetization, described by t^{3/4} at short times. Fast
precessing nuclear spins, included in the model microscopically, only
moderately speed up the relaxation.Comment: 10 pages, 9 figures, to be published in EPJ
A microscopic model for a class of mixed-spin quantum antiferromagnets
We propose a microscopic model that describes the magnetic behavior of the
mixed-spin quantum systems RBaNiO (R= magnetic rare earth). An
evaluation of the properties of this model by Quantum Monte Carlo simulations
shows remarkable good agreement with the experimental data and provides new
insight into the physics of mixed-spin quantum magnets.Comment: revised version to be published in Phys. Rev.
Method for estimating potential recognition capacity of texture-based biometrics
When adopting an image-based biometric system, an important factor for consideration is its potential recognition capacity, since it not only defines the potential number of individuals likely to be identifiable, but also serves as a useful figure-of-merit for performance. Based on block transform coding commonly used for image compression, this study presents a method to enable coarse estimation of potential recognition capacity for texture-based biometrics. Essentially, each image block is treated as a constituent biometric component, and image texture contained in each block is binary coded to represent the corresponding texture class. The statistical variability among the binary values assigned to corresponding blocks is then exploited for estimation of potential recognition capacity. In particular, methodologies are proposed to determine appropriate image partition based on separation between texture classes and informativeness of an image block based on statistical randomness. By applying the proposed method to a commercial fingerprint system and a bespoke hand vein system, the potential recognition capacity is estimated to around 10^36 for a fingerprint area of 25 â
mm^2 which is in good agreement with the estimates reported, and around 10^15 for a hand vein area of 2268 â
mm^2 which has not been reported before
LA ACUAPONĂA, DIVERSIFICACIĂN PRODUCTIVA SUSTENTABLE
An aquaponics system was evaluated as a model for diversification of food production with a completely randomized experimental design through the variables of water temperature (20-31.5 °C), pH (5.7-7.6) and oxygen (4.0-5.3 mg L-1), applied to parsley (Petroselinum crispum), serrano pepper (Capsicum annuum) and ornamental pepper (Capsicum sp.) with controls grown in traditional cultivation with a 2:1 soil-tezontle substrate, during a 4-month period, along with white tilapia, var. Rocky Mountain (Oreochromis niloticusxO. aureus). Results indicated that the effluent derived was too salty (C4). The tilapia had a weight gain of 206 g in 120 days and a survival of 91%. Serrano pepper grown in aquaponics (11 cm) did not show statistically significant differences in terms of plant growth (P>0.05), compared to traditional cultivation (70 cm). Parsley did not develop in aquaponics due to the salinity. The ornamental pepper had a limited development with a height lower than the control grown in traditional cultivation, so the conclusion is that the effluent limits the selection of species to be cultivated, although the potential for species that tolerate salinity can be seen.Se evaluĂł un sistema acuapĂłnico como modelo de diversificaciĂłn productiva de alimentos en un diseño experimental completamente al azar mediante las variables temperatura del agua (20-31.5 °C), pH (5.7-7.6) y oxĂgeno (4.0-5.3 mg L-1), aplicados a perejil (Petroselinum crispum), chile serrano (Capsicum annuum) y chile de ornato (Capsicum sp.) con testigos en siembra tradicional con sustrato tierra-tezontle 2:1, en un periodo de 4 meses, ademĂĄs de tilapia blanca var. Rocky mountain (Oreochromis niloticusxO. aureus). Los resultados indicaron que el efluente derivado fue muy salino (C4). La tilapia tuvo una ganancia de peso de 206 g en 120 dĂas y sobrevivencia de 91%. El chile serrano cultivado en acuaponĂa (11 cm) no mostrĂł diferencias estadĂsticamente significativas en crecimiento de la planta (P>0.05), en comparaciĂłn con la siembra tradicional (70 cm). El perejil no se desarrollĂł en acuaponĂa atribuido a la salinidad. El chile de ornato tuvo un desarrollo limitado con altura menor al testigo bajo siembra tradicional, concluyendo que el efluente delimita la selecciĂłn de las especies a cultivar, apreciando potencial para especies tolerantes a salinidad
Autoantibodies against EPCR are found in antiphospholipid syndrome and are a risk factor for fetal death
The antiphospholipid syndrome (APS) is associated with thrombosis and fetal death but the pathologic mechanisms are poorly understood. Since endothelial protein C receptor (EPCR) plays a role in the anticoagulant system and in placental development, we hypothesized that anti-EPCR autoantibodies may be involved in clinical manifestations of APS and in fetal loss. The levels of immunoglobulin M (IgM) and IgG anti-EPCR autoantibodies were analyzed by enzyme-linked immunosorbent assay (ELISA) in 43 patients with APS and 43 controls. Anti-EPCR levels were higher in APS patients than in controls. Interestingly, one of the IgM anti-EPCR autoantibodies inhibited the generation of activated protein C on endothelium. Since markedly high anti-EPCR levels were found in women with fetal death, 87 patients with a first episode of unexplained fetal death were subsequently analyzed and their anti-EPCR levels were compared with 87 matched controls. We found that anti-EPCR autoantibodies constitute an independent risk factor for a first fetal death episode: the adjusted odds ratios (ORs) for anti-EPCR autoantibodies above the 95th percentile were 23.0 (95% confidence interval [CI], 2.0-266.3) for IgM and 6.8 (95% CI, 1.2-38.4) for IgG. Anti-EPCR autoantibodies can be detected in APS patients and are independent risk factors for fetal death
Probing exotic phenomena at the interface of nuclear and particle physics with the electric dipole moments of diamagnetic atoms: A unique window to hadronic and semi-leptonic CP violation
The current status of electric dipole moments of diamagnetic atoms which
involves the synergy between atomic experiments and three different theoretical
areas -- particle, nuclear and atomic is reviewed. Various models of particle
physics that predict CP violation, which is necessary for the existence of such
electric dipole moments, are presented. These include the standard model of
particle physics and various extensions of it. Effective hadron level combined
charge conjugation (C) and parity (P) symmetry violating interactions are
derived taking into consideration different ways in which a nucleon interacts
with other nucleons as well as with electrons. Nuclear structure calculations
of the CP-odd nuclear Schiff moment are discussed using the shell model and
other theoretical approaches. Results of the calculations of atomic electric
dipole moments due to the interaction of the nuclear Schiff moment with the
electrons and the P and time-reversal (T) symmetry violating
tensor-pseudotensor electron-nucleus are elucidated using different
relativistic many-body theories. The principles of the measurement of the
electric dipole moments of diamagnetic atoms are outlined. Upper limits for the
nuclear Schiff moment and tensor-pseudotensor coupling constant are obtained
combining the results of atomic experiments and relativistic many-body
theories. The coefficients for the different sources of CP violation have been
estimated at the elementary particle level for all the diamagnetic atoms of
current experimental interest and their implications for physics beyond the
standard model is discussed. Possible improvements of the current results of
the measurements as well as quantum chromodynamics, nuclear and atomic
calculations are suggested.Comment: 46 pages, 19 tables and 16 figures. A review article accepted for
EPJ
The Brazilian Developments On The Regional Atmospheric Modeling System (brams 5.2): An Integrated Environmental Model Tuned For Tropical Areas
Fundação de Amparo Ă Pesquisa do Estado de SĂŁo Paulo (FAPESP)Fundação de Amparo Ă Pesquisa do Estado de SĂŁo Paulo (FAPESP)Fundação de Amparo Ă Pesquisa do Estado de SĂŁo Paulo (FAPESP)Conselho Nacional de Desenvolvimento CientĂfico e TecnolĂłgico (CNPq)We present a new version of the Brazilian developments on the Regional Atmospheric Modeling System (BRAMS), in which different previous versions for weather, chemistry, and carbon cycle were unified in a single integrated modeling system software. This new version also has a new set of state-of-the-art physical parameterizations and greater computational parallel and memory usage efficiency. The description of the main model features includes several examples illustrating the quality of the transport scheme for scalars, radiative fluxes on surface, and model simulation of rainfall systems over South America at different spatial resolutions using a scale aware convective parameterization. Additionally, the simulation of the diurnal cycle of the convection and carbon dioxide concentration over the Amazon Basin, as well as carbon dioxide fluxes from biogenic processes over a large portion of South America, are shown. Atmospheric chemistry examples show the model performance in simulating near-surface carbon monoxide and ozone in the Amazon Basin and the megacity of Rio de Janeiro. For tracer transport and dispersion, the model capabilities to simulate the volcanic ash 3-D redistribution associated with the eruption of a Chilean volcano are demonstrated. The gain of computational efficiency is described in some detail. BRAMS has been applied for research and operational forecasting mainly in South America. Model results from the operational weather forecast of BRAMS on 5km grid spacing in the Center for Weather Forecasting and Climate Studies, INPE/Brazil, since 2013 are used to quantify the model skill of near-surface variables and rainfall. The scores show the reliability of BRAMS for the tropical and subtropical areas of South America. Requirements for keeping this modeling system competitive regarding both its functionalities and skills are discussed. Finally, we highlight the relevant contribution of this work to building a South American community of model developers. © Author(s) 2017.1011892222014/01563-1, FAPESP, Fundação de Amparo Ă Pesquisa do Estado de SĂŁo Paulo2014/01564-8, FAPESP, Fundação de Amparo Ă Pesquisa do Estado de SĂŁo Paulo2015/10206-0, FAPESP, Fundação de Amparo Ă Pesquisa do Estado de SĂŁo Paulo306340/2011-9, Conselho Nacional de Desenvolvimento CientĂfico e TecnolĂłgicoFundação de Amparo Ă Pesquisa do Estado de SĂŁo Paulo (FAPESP)Fundação de Amparo Ă Pesquisa do Estado de SĂŁo Paulo (FAPESP)Fundação de Amparo Ă Pesquisa do Estado de SĂŁo Paulo (FAPESP)Conselho Nacional de Desenvolvimento CientĂfico e TecnolĂłgico (CNPq
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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