Graded identities of block-triangular matrices

Let $F$ be an infinite field and $UT(d_1,\dots, d_n)$ be the algebra of upper block-triangular matrices over $F$. In this paper we describe a basis for the $G$-graded polynomial identities of $UT(d_1,\dots, d_n)$, with an elementary grading induced by an $n$-tuple of elements of a group $G$ such that the neutral component corresponds to the diagonal of $UT(d_1,\dots,d_n)$. In particular, we prove that the monomial identities of such algebra follow from the ones of degree up to $2n-1$. Our results generalize for infinite fields of arbitrary characteristic, previous results in the literature which were obtained for fields of characteristic zero and for particular $G$-gradings. In the characteristic zero case we also generalize results for the algebra $UT(d_1,\dots, d_n)\otimes C$ with a tensor product grading, where $C$ is a color commutative algebra generating the variety of all color commutative algebras.Comment: 24 pages and 39 references. We have added section 5 in the text about tensor products by color commutative superalgebra

In vitroandin vivoassessment of the effect ofLaurus novocanariensisoil and essential oil in human skin

Laurus novocanariensis is an endemic plant from the Madeira Island forest that derives a fatty oil, with a strong spicy odour, from its berries that has been used for centuries in traditional medicine to treat skin ailments. This work aimed to investigate the effect of the application of both the oil and its essential oil on normal skin, to assess their safety and potential benefits. Diffusion studies with Franz cells using human epidermal membranes were conducted. The steady-state fluxes of two model molecules through untreated skin were compared with those obtained after a 2-h pre-treatment with either the oil or the essential oil. Additionally, eleven volunteers participated in the in vivo study that was conducted on the forearm and involved daily application of the oil for 5 days. Measurements were performed every day in the treated site with bioengineering methods that measure erythema, irritation and loss of barrier function. Slightly higher steady-state fluxes were observed for both the lipophilic and the hydrophilic molecule when the epidermal membranes were pre-treated. Nevertheless, such differences had no statistical significance, which seems to confirm that neither the oil nor the essential oil impaired the epidermal barrier. Results collected with the Chromameter, the Laser Doppler Flowmeter and the visual scoring are in agreement with those established in the in vitro study. They indicate that the repeated application of the oil did not cause erythema, because the results observed in the first day of the study were maintained throughout the week. Application of the oil did not affect the skin barrier function, because the transepidermal water loss remained constant throughout the study. The stratum corneum hydration was slightly reduced on days 4 and 5. This work shows that both the oil and the essential oil were well tolerated by the skin and did not cause significant barrier impairment or irritation.info:eu-repo/semantics/publishedVersio

Three Li-rich K giants: IRAS 12327-6523, IRAS 13539-4153, and IRAS 17596-3952

We report on spectroscopic analyses of three K giants previously suggested to be Li-rich: IRAS 12327-6523, IRAS 13539-4153, and IRAS 17596-3952. High-resolution optical spectra and the LTE model atmospheres are used to derive the stellar parameters: ($T_{\rm eff}$, log $g$, [Fe/H]), elemental abundances, and the isotopic ratio $^{12}$C/$^{13}$C. IRAS 13539-4153 shows an extremely high Li abundance of $\log\epsilon$(Li) $\approx$ 4.2, a value ten times more than the present Li abundance in the local interstellar medium. This is the third highest Li abundance yet reported for a K giant. IRAS 12327-6523 shows a Li abundances of $\log\epsilon$(Li)$\approx$ 1.4. IRAS 17596-3952 is a rapidly rotating ($V{\sin i}$ $\approx$ 35 km s$^{-1}$) K giant with $\log\epsilon$(Li) $\approx$ 2.2. Infrared photometry which shows the presence of an IR excess suggesting mass-loss. A comparison is made between these three stars and previously recognized Li-rich giants.Comment: 17 pages, 6 figures, accepted for A

As aulas de campo na educação em geologia : uma proposta para a região da mina da panasqueira, Portugal central

Este estudo desenvolveu-se no âmbito das actividades de campo como uma estratégia importante no ensino da Geologia, também numa perspectiva ambiental. O objectivo principal relaciona-se com o valor atribuído à formulação e resolução de questões-problema de âmbito ambiental (local/regional) na Educação em Ciências da Terra. Para isso, com base na avaliação efectuada através da aplicação de um questionário a professores do ensino básico e secundário (N= 52), a leccionar Ciências Naturais e Biologia e Geologia em escolas dos concelhos do Fundão e da Covilhã (Portugal Central), e tendo em conta a dinâmica pretendida com a implementação das Orientações Curriculares actuais, construiu-se uma proposta de modelo de aula de campo para o ensino e aprendizagem das Ciências da Terra, numa perspectiva do Ensino Experimental das Ciências

High Susceptibility Of Activated Lymphocytes To Oxidative Stress-induced Cell Death.

The present study provides evidence that activated spleen lymphocytes from Walker 256 tumor bearing rats are more susceptible than controls to tert-butyl hydroperoxide (t-BOOH)-induced necrotic cell death in vitro. The iron chelator and antioxidant deferoxamine, the intracellular Ca2+ chelator BAPTA, the L-type Ca2+ channel antagonist nifedipine or the mitochondrial permeability transition inhibitor cyclosporin A, but not the calcineurin inhibitor FK-506, render control and activated lymphocytes equally resistant to the toxic effects of t-BOOH. Incubation of activated lymphocytes in the presence of t-BOOH resulted in a cyclosporin A-sensitive decrease in mitochondrial membrane potential. These results indicate that the higher cytosolic Ca2+ level in activated lymphocytes increases their susceptibility to oxidative stress-induced cell death in a mechanism involving the participation of mitochondrial permeability transition.80137-4

Avaliação do estado nutricional e perfil alimentar de alunos do ensino fundamental de uma escola municipal, localizada na região leste da cidade de Foz do Iguaçu –PR

Introdução. A Educação Alimentar Nutricional dispõe-se a influenciar positivamente na formação de hábitos saudáveis de qualquer pessoa, em qualquer faixa etária, visado o reconhecimento de benefícios de uma alimentação sadia na Pré-escola, como forma de melhoria nas práticas alimentares dos escolares. Objetivo. Avaliar o perfil nutricional estudantes de uma escola da rede pública na cidade de Foz do Iguaçu – PR. Metodologia. Foram avaliadas 157 crianças do Ensino Fundamental I de uma escola municipal do município de Foz do Iguaçu (PR). Para as variáveis antropométricas foi aferido (peso e altura) e aplicado um questionário de 3 perguntas para avaliar o conhecimento dos alunos. A classificação do Índice de Massa Corporal (IMC) foi realizada a partir do cálculo do IMC por idade pela calculadora Antro Plus e a tabela de classificação da Organização Mundial de Saúde. Resultados. Das crianças avaliadas, 45,8% eram do sexo masculino e 54,2% do sexo feminino. A prevalência de obesidade entre os meninos foi maior do que das meninas (16,7% nos meninos e 3,52% nas meninas). As meninas apresentaram maior prevalência de eutrofia (67,05%) do que os meninos (54%). Independentemente do sexo, os alunos com maior índice de baixo peso se encontraram entre o 1° e 3° anos, e os alunos mais obesos se encontraram no 5° ano. Sobre o questionário, o percentual de crianças que conheciam os alimentos mais saudáveis foi de 54,4% e 45,6% não conheciam os alimentos. Conclusão. Conclui-se que a maioria dos alunos avaliados apresentaram eutrofia, porém devido casos de obesidade e baixo peso, é necessário que a escola realize ações de educação nutricional para melhorar esses índices

Models of Metal Poor Stars with Gravitational Settling and Radiative Accelerations: I. Evolution and Abundance Anomalies

Evolutionary models have been calculated for Pop II stars of 0.5 to 1.0$M_\odot$ from the pre-main-sequence to the lower part of the giant branch. Rosseland opacities and radiative accelerations were calculated taking into account the concentration variations of 28 chemical species, including all species contributing to Rosseland opacities in the OPAL tables. The effects of radiative accelerations, thermal diffusion and gravitational settling are included. While models were calculated both for Z=0.00017 and 0.0017, we concentrate on models with Z=0.00017 in this paper. These are the first Pop II models calculated taking radiative acceleration into account. It is shown that, at least in a 0.8$M_\odot$ star, it is a better approximation not to let Fe diffuse than to calculate its gravitational settling without including the effects of $g_{rad}(Fe)$. In the absence of any turbulence outside of convection zones, the effects of atomic diffusion are large mainly for stars more massive than 0.7$M_\odot$. Overabundances are expected in some stars with \teff \ge 6000K. Most chemical species heavier than CNO are affected. At 12 Gyr, overabundance factors may reach 10 in some cases (e.g. for Al or Ni) while others are limited to 3 (e.g. for Fe). The calculated surface abundances are compared to recent observations of abundances in globular clusters as well as to observations of Li in halo stars. It is shown that, as in the case of Pop I stars, additional turbulence appears to be present.Comment: 40 pages, 17 color figures, to appear in The Astrophysical Journal, April 2002 (paper with original high resolution figures can be found at http://www.cerca.umontreal.ca/~richer/Fichiersps/popII_1.ps