Non-universal behavior for aperiodic interactions within a mean-field approximation

We study the spin-1/2 Ising model on a Bethe lattice in the mean-field limit, with the interaction constants following two deterministic aperiodic sequences: Fibonacci or period-doubling ones. New algorithms of sequence generation were implemented, which were fundamental in obtaining long sequences and, therefore, precise results. We calculate the exact critical temperature for both sequences, as well as the critical exponent $\beta$, $\gamma$ and $\delta$. For the Fibonacci sequence, the exponents are classical, while for the period-doubling one they depend on the ratio between the two exchange constants. The usual relations between critical exponents are satisfied, within error bars, for the period-doubling sequence. Therefore, we show that mean-field-like procedures may lead to nonclassical critical exponents.Comment: 6 pages, 7 figures, to be published in Phys. Rev.

Heat conduction in the hollow sphere with a power-law variation of the external heat transfer coefficient

The conduction phenomenon in an insulated sphere is re-worked through a dimensionless approach, where the heat transfer coefficient dependence on the external radius and on the surface temperature, as in the case of forced and free convection, is taken into account. Assuming a power law variation of the convection coefficient [1, 2], and using the results of Sparrow [3], equations and graphs for the most important dimensionless parameters are presented. The developed equations show, for example, that as the insulation thickness increases the heat transfer rate tends to a positive value, independent of the considered case: constant convection coefficient, forced or free convection.http://www.sciencedirect.com/science/article/B6V3J-42MP1M2-3/1/6228c6d77bbaac53e7833e6cd67d8ef

Heat conduction in the hollow sphere with a power-law variation of the external heat transfer coefficient

The conduction phenomenon in an insulated sphere is re-worked through a dimensionless approach, where the heat transfer coefficient dependence on the external radius and on the surface temperature, as in the case of forced and free convection, is taken into account. Assuming a power law variation of the convection coefficient [1, 2], and using the results of Sparrow [3], equations and graphs for the most important dimensionless parameters are presented. The developed equations show, for example, that as the insulation thickness increases the heat transfer rate tends to a positive value, independent of the considered case: constant convection coefficient, forced or free convection.http://www.sciencedirect.com/science/article/B6V3J-42MP1M2-3/1/6228c6d77bbaac53e7833e6cd67d8ef

Hierarchy plus anarchy in quark masses and mixings

We introduce a new parameterisation of the effect of unknown corrections from new physics on quark and lepton mass matrices. This parameterisation is used in order to study how the hierarchies of quark masses and mixing angles are modified by random perturbations of the Yukawa matrices. We discuss several examples of flavour relations predicted by different textures, analysing how these relations are influenced by the random perturbations. We also comment on the unlikely possibility that unknown corrections contribute significantly to the hierarchy of masses and mixings.Comment: LaTeX, 18 pages, 16 PS figure

Characterization of magnetron co-sputtered W-doped C-based films

In this paper, W-doped C-based coatings were deposited on steel and silicon substrates by RF magnetron sputtering, using W and C targets, varying the cathode power applied to the W target and the substrate bias. The chemical composition was varied by placing the substrates in a row facing the C and W targets. W content in the films increased from 1 to 2 at.% over the C target to ~ 73 at.% over the W target. The coatings with W content lower than ~ 12 at.% and ~ 23 at.%, for biased and unbiased conditions, respectively, showed X-ray amorphous structures, although carbide nanocrystals must exist as shown by the detection of the WC1-x phase in films with higher W content. C-rich films were very dense and developed a columnar morphology with increasing W content. An improvement in the hardness (from 10 GPa, up to 25 GPa) of the films was achieved either when negative substrate bias was used in the deposition, or when the WC1-x phase was detected by X-ray diffraction. The adhesion of the coatings is very low with spontaneous spallation of those deposited with negative substrate bias higher than 45 V. Varieties in cathode power (90 W or 120 W) applied to the W target showed no observable influence on the characteristics of the films.http://www.sciencedirect.com/science/article/B6TW0-4KXVCT6-6/1/a285b093ad366f2b40c4eb884a4442c

Experimental Adhesion Prevention Studies: A Comparative Study in a Rabbit Model

Background: Adhesions formation after abdominal surgery is a problem that causes many complications in the patient’s future life. In this study we compare the possible individual effects of Ringer ́s lactate, Adept® and Mesofol® and the combined effects of Adept® and Mesofol® in the prevention of post surgical adhesions formation in a standardised rabbit model.Materials and Methods: 90 rabbits were divided into 9 groups. The same experimental method was used in all rabbits to produce adhesions, consisting of cecal and sigmoid abrasion and excision of parietal peritoneum. The rabbits were operated after 2 weeks to assess the adhesions occurring. The results were analysed using the chi-square test and the Fisher exact test when needed.Results: Comparison of adhesion stages demonstrated a significant difference between the control group and the Adept® groups (p<0.05) in both branches. The adhesion grade of the combined treatment groups (G5 and G9) was not statistically significant (p>0.05). In the Mesofol® group and the combined group, four and two rabbits, respectively, developed granulomas. Conclusions: Adept® used individually reduced the adhesion grade. The Adept® and Mesofol® combination was less effective in reducing adhesion formation in comparison to the Adept® group by itself. On the other hand, in our experimental study, the usage of Mesofol®, alone or in combination, caused foreign body granulomas in 6 animals. Although the literature is very sufficient in comparison several materials for decreasing adhesion formation, we believe that our study provides more valuable evidence in this area. Due to the appearance of six cases of foreign body granulomas, detailed studies focused on this matter are needed in the future. Keywords: Post-operative adhesions; comparative study; prevention; rabbit model. Introdução: A formação de aderências após a cirurgia abdominal é um problema que causa muitas complicações na vida futura do doente. Neste estudo, comparamos os possíveis efeitos individuais do Ringer lactato, Adept® e do Mesofol®, e os efeitos combinados do Adept® e do Mesofol® na prevenção da formação de aderências pós-cirúrgicas num modelo padronizado de coelhos.Materiais e Métodos: 90 coelhos foram divididos em nove grupos. O mesmo método experimental foi utilizado em todos os coelhos para favorecer a produção de aderências, realizando abrasão do cego e da sigmoideia e excisão do peritoneu parietal. Os coelhos foram operados após duas semanas para avaliar a ocorrência de aderências. Os resultados foram analisados por meio do teste do qui-quadrado e do teste exacto de Fisher, quando necessário.Resultados: A comparação em estadios de aderência demonstrou uma diferença significativa entre o grupo controlo e os grupos Adept® (p <0,05) em ambos os ramos. O grau de aderências dos grupos de tratamento combinado (G5 e G9) não foi estatisticamente significativo (p <0,05). No grupo do Mesofol® e no grupo combinado, quatro e dois coelhos, respectivamente, desenvolveram granulomas. Conclusões: Adept® utilizado individualmente reduziu o grau de aderências. O Adept® combinado com o Mesofol® foi menos eficaz na redução da formação de aderências em comparação com o grupo do Adept®, por si só. Por outro lado, o uso de Mesofol® isoladamente ou em conjunto podem aumentar o risco de granulomas. Estudos mais detalhados são necessários, e futuros estudos sobre a eficácia de um material para diminuir a formação de aderências deve incluir uma comparação de controle de diversos materiais num mesmo modelo.Palavras-Chave: aderências pós-operatórias; estudo comparativo; prevenção; modelo animal em coelhos

A three-parameter model for the neutrino mass matrix

Using the type-II seesaw mechanism with three Higgs doublets phi_alpha (alpha = e, mu, tau) and four Higgs triplets, we build a model for lepton mixing based on a 384-element horizontal symmetry group, generated by the permutation group S_3 and by six Z_2 transformations. The charged-lepton mass matrix is diagonal; the symmetries of the model would require all the three masses m_alpha to be equal, but different vacuum expectation values of the phi_alpha allow the m_alpha to split. The number of parameters in the Majorana neutrino mass matrix m_nu depends on two options: full breaking of the permutation group S_3, or leaving a mu--tau interchange symmetry intact; and hard or spontaneous violation of CP. We discuss in detail the case with the minimal number of three parameters, wherein m_nu is real, symmetric under mu--tau interchange, and has equal diagonal elements. In that case, CP is conserved in lepton mixing, atmospheric neutrino mixing is maximal, and theta_{13} = 0; moreover, the type of neutrino mass spectrum and the absolute neutrino mass scale are sensitive functions of the solar mixing angle.Comment: 16 pages, one eps figure; some clarifications added, contains new section 5, version accepted for publication in J. Phys.

Political connections and corporate social responsibility reporting in Portugal

This paper examines the relation between firms’ political connections and corporate social responsibility (CSR) reporting in Portugal. We argue that in settings where the existence of political connections are viewed as damaging collective interests of stakeholders, political connected firms can deal with legitimacy issues from such connections by resorting to CSR practices and the reporting thereof. Using archival data from a panel sample of 36 firms from Portugal between 2009 and 2012, we examine the relation between political connections and CSR reporting by way of regression analysis. We find a positive relation between political connections and CSR reporting. This study draws on legitimacy theory to highlight that CSR can be used to deal with stakeholder activism and vigilance pertaining to suspicion related to the existence of political connections.info:eu-repo/semantics/acceptedVersio

Hepatite C em toxicodependentes: acompanhamento e acesso à terapêutica

A hepatite C constitui, actualmente, um grave problema de saúde pública. Estima-se que existam, em todo o mundo, 180 milhões de pessoas com infecção crónica por vírus da hepatite C (VHC) e que a sua prevalência na população portuguesa varie entre 1 e 1,5%. Em Portugal, não existem normas de orientação actualizadas de tratamento, nem recomendações para o diagnóstico e acompanhamento dos doentes com VHC e, em particular, para os UDEVs. O presente artigo reúne informação de consenso relativa à de prática clínica e propõe algumas orientações para o acompanhamento e acessibilidade ao tratamento dos doentes toxicodependentes com infecção crónica por VHC, em Portugal

Large Neutrino Mixing with Universal Strength of Yukawa Couplings

We analyse, within the framework of universal strength for Yukawa couplings (USY), various structures for the Dirac and Majorana neutrino mass matrices giving rise, through the see-saw mechanism, to a degenerate mass spectrum. A specific USY ansatz is presented for the charged lepton and neutrino effective mass matrix, leading to quasi-degenerate neutrinos and a leptonic mixing matrix which provides a large angle solution for both the atmospheric and solar neutrino problems.Comment: 7 pages, ReVTeX, small comments adde