49 research outputs found
Nanostructuring as a procedure to control the field dependence of the magnetocaloric effect
In this work, the field dependence of the magnetocaloric effect of Gd bulk samples has been enhanced through
nanostructuring of the material. Nanostructuring consists in multilayers preparation by alternative rf-sputtering
deposition of Gd layers and Ti spacers onto glass substrates. The results obtained for the multilayers were compared to those obtained for the Gd bulk. Assuming a power law for the field dependence of the magnetic entropy
change (ΔSM ∝ Hn
), higher field dependences close to the transition in a wider temperature range are obtained for
the multilayer material (n = 1.0) with respect to the bulk counterpart (n = 0.78). The effect of a Curie temperature distribution in the multilayer material (due to variations of the layer thickness) has been studied through
numerical simulations to explain the observed field dependence of the magnetocaloric effect, obtaining a remarkable agreement between experiments and results.Ministerio de Economía y Competitividad español y EU-FEDER. MAT2013-45165-P y MAT2016-77265-RMinistry of Education and Science of the Russian Federation. Project No. 258
Parametric Polyhedra with at least Lattice Points: Their Semigroup Structure and the k-Frobenius Problem
Given an integral matrix , the well-studied affine semigroup
\mbox{ Sg} (A)=\{ b : Ax=b, \ x \in {\mathbb Z}^n, x \geq 0\} can be
stratified by the number of lattice points inside the parametric polyhedra
. Such families of parametric polyhedra appear in
many areas of combinatorics, convex geometry, algebra and number theory. The
key themes of this paper are: (1) A structure theory that characterizes
precisely the subset \mbox{ Sg}_{\geq k}(A) of all vectors b \in \mbox{
Sg}(A) such that has at least solutions. We
demonstrate that this set is finitely generated, it is a union of translated
copies of a semigroup which can be computed explicitly via Hilbert bases
computations. Related results can be derived for those right-hand-side vectors
for which has exactly solutions or fewer
than solutions. (2) A computational complexity theory. We show that, when
, are fixed natural numbers, one can compute in polynomial time an
encoding of \mbox{ Sg}_{\geq k}(A) as a multivariate generating function,
using a short sum of rational functions. As a consequence, one can identify all
right-hand-side vectors of bounded norm that have at least solutions. (3)
Applications and computation for the -Frobenius numbers. Using Generating
functions we prove that for fixed the -Frobenius number can be
computed in polynomial time. This generalizes a well-known result for by
R. Kannan. Using some adaptation of dynamic programming we show some practical
computations of -Frobenius numbers and their relatives
Extended WKB method, resonances and supersymmetric radial barriers
Semiclassical approximations are implemented in the calculation of position
and width of low energy resonances for radial barriers. The numerical
integrations are delimited by t/T<<8, with t the period of a classical particle
in the barrier trap and T the resonance lifetime. These energies are used in
the construction of `haired' short range potentials as the supersymmetric
partners of a given radial barrier. The new potentials could be useful in the
study of the transient phenomena which give rise to the Moshinsky's diffraction
in time.Comment: 12 pages, 4 figures, 3 table
GBA and APOE ε4 associate with sporadic dementia with Lewy bodies in European genome wide association study
Dementia with Lewy Bodies (DLB) is a common neurodegenerative disorder with poor prognosis and mainly unknown pathophysiology. Heritability estimates exceed 30% but few genetic risk variants have been identified. Here we investigated common genetic variants associated with DLB in a large European multisite sample. We performed a genome wide association study in Norwegian and European cohorts of 720 DLB cases and 6490 controls and included 19 top-associated single-nucleotide polymorphisms in an additional cohort of 108 DLB cases and 75545 controls from Iceland. Overall the study included 828 DLB cases and 82035 controls. Variants in the ASH1L/GBA (Chr1q22) and APOE ε4 (Chr19) loci were associated with DLB surpassing the genome-wide significance threshold (p < 5 × 10). One additional genetic locus previously linked to psychosis in Alzheimer's disease, ZFPM1 (Chr16q24.2), showed suggestive association with DLB at p-value < 1 × 10. We report two susceptibility loci for DLB at genome-wide significance, providing insight into etiological factors. These findings highlight the complex relationship between the genetic architecture of DLB and other neurodegenerative disorders
International nosocomial infection control consortium (INICC) report, data summary of 36 countries, for 2004-2009
The results of a surveillance study conducted by the International Nosocomial Infection Control Consortium (INICC) from January 2004 through December 2009 in 422 intensive care units (ICUs) of 36 countries in Latin America, Asia, Africa, and Europe are reported. During the 6-year study period, using Centers for Disease Control and Prevention (CDC) National Healthcare Safety Network (NHSN; formerly the National Nosocomial Infection Surveillance system [NNIS]) definitions for device-associated health care-associated infections, we gathered prospective data from 313,008 patients hospitalized in the consortium's ICUs for an aggregate of 2,194,897 ICU bed-days. Despite the fact that the use of devices in the developing countries' ICUs was remarkably similar to that reported in US ICUs in the CDC's NHSN, rates of device-associated nosocomial infection were significantly higher in the ICUs of the INICC hospitals; the pooled rate of central line-associated bloodstream infection in the INICC ICUs of 6.8 per 1,000 central line-days was more than 3-fold higher than the 2.0 per 1,000 central line-days reported in comparable US ICUs. The overall rate of ventilator-associated pneumonia also was far higher (15.8 vs 3.3 per 1,000 ventilator-days), as was the rate of catheter-associated urinary tract infection (6.3 vs. 3.3 per 1,000 catheter-days). Notably, the frequencies of resistance of Pseudomonas aeruginosa isolates to imipenem (47.2% vs 23.0%), Klebsiella pneumoniae isolates to ceftazidime (76.3% vs 27.1%), Escherichia coli isolates to ceftazidime (66.7% vs 8.1%), Staphylococcus aureus isolates to methicillin (84.4% vs 56.8%), were also higher in the consortium's ICUs, and the crude unadjusted excess mortalities of device-related infections ranged from 7.3% (for catheter-associated urinary tract infection) to 15.2% (for ventilator-associated pneumonia). Copyright © 2012 by the Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved
Aspectos microbiológicos e físico-químicos da parte interna da paleta suína curada, maturada e fermentada durante a etapa de processamento e armazenamento Microbiological and physical chemical aspects in the internal parts pig palette cured, matured and fermented during processing and storage
Utilizou-se como matéria-prima a paleta suína e elaborou-se um produto cárneo similar ao presunto curado espanhol. Acompanhou-se a evolução de alguns parâmetros físico-químicos (pH, a w, NO2, umidade, cloretos) e microbiológicos (bactérias mesófilos, lácticas, Micrococcacea, Staphylococcus xylosus), na parte interna da paleta suína, e relacionou-os com as ações que os mesmos exercem nos produtos cárneos fermentados e curados, nas diferentes fases de processamento e armazenamento, tendo em vista que o produto elaborado com a paleta suína é similar a esses produtos cárneos. Os resultados mostraram que as concentrações de cloretos do quinto ponto de coleta (20° dia) em diante apresentaram ação bacteriostática frente às bactérias que alteram o produto, e que os valores de a w menores do que 0,93 e de umidade inferiores a 64%, durante o período de armazenamento, agiram como obstáculos frente ao desenvolvimento das bactérias da família Enterobacteriaceae. Representantes da família Microccocaceae e do grupo das bactérias ácido lácticas desenvolveram-se em baixos valores de a w e em alta concentração de cloreto.<br>Pig palette was used as ra w material, and a meat product similar to the Spanish cured ham was produced. Some physical and chemical parameters (pH, a w, NO2, moisture and sodium chloride), as well as microbiological countings (mesophilic bacteria, lactic acid bacteria, Micrococcaceae, Staphylococcus xylosus) were assessed in the internal part pig palette, during the steps of processing and storage. These parameters were correlated with the actions that they exert in fermented and cured meat products. The results showed that the concentration of sodium chloride after the 20th day presented bacteriostatic action on the bacteria that modify the product. The values of a w lower than 0.93 and moisture lower than 64%, during the storage period, acted as obstacles to the development of bacteria of the Entreobacteriaceae family. Representatives of the Microccocaceae family and of the lactic acid bacteria grew at low a w and at high concentration of sodium chloride