On the error of calculation of heat gains through walls by methods using constant decrement factor and time lag values

A transient heat transfer model was developed to numerically predict the thermal behaviour of the external walls of a room under realistic outdoor conditions. The excitation is not simply sinusoidal even though it is considered to have daily periodicity. The numerical model is based on the finite difference method and handles one-dimensional heat conduction through multilayered walls. The boundary condition at the outer surface of the wall is described with the sol-air temperature concept. The temperatures of indoor air and of other internal surfaces in the room are assumed to be equal and constant. The numerical results were used to calculate values of the decrement factor and time lag of several walls. The calculation followed two methods found in literature, in which these parameters are assumed constant, distinguished by the temperature evolution used: the sol-air or the wall's outer surface. Additionally, the inner surface temperature is used in both methods. The walls investigated range from low to high mass construction, face towards various directions and have light or dark coloured sunlit outer surfaces. The heat fluxes at the inner surface of the walls predicted by numerical modelling and estimated by the simplified methods are compared in detail to conclude on the validity of these simplified methods. As a by-product it is also possible to conclude on the dependence of the decrement factor and of the time lag on the outer surface colour and on the orientation of different types of walls. The results show that both simplified methods have poor accuracy in a significant number of cases. Also, it was found that the wall's azimuth significantly affects the time lag

Two photon decay of π0\pi^0 and η\eta at finite temperature and density

A comparative study of the anomalous decays $\pi^0, \eta \to\gamma\gamma$, at finite temperature and at finite density, is performed in the framework of the three--flavor Nambu--Jona-Lasinio. The similarities and differences between both scenarios are discussed. In both cases the lifetimes of these mesons decrease significantly at the critical point, although this might not be sufficient to observe enhancement of these decays in heavy-ion collisions.Comment: 5 pages, 1 figure. Talk given at Strange Quark Matter 2004, Cape Town, South Africa, 15-20 September, 200

The QCD critical end point in the PNJL model

We investigate the role played by the Polyakov loop in the dynamics of the chiral phase transition in the framework of the so-called PNJL model in the SU(2)sector. We present the phase diagram where the inclusion of the Polyakov loop moves the critical points to higher temperatures, compared with the NJL model results. The critical properties of physical observables, such as the baryon number susceptibility and the specific heat, are analyzed in the vicinity of the critical end point, with special focus on their critical exponents. The results with the PNJL model are closer to lattice results and we also recover the universal behavior of the critical exponents of both the baryon susceptibility and the specific heat.Comment: 12 pages, 3 figures, EPL versio

Left atrial deformation analysis by speckle tracking echocardiography to predict exercise capacity after myocardial infarction

Introduction: Left atrial (LA) size and function are associated with outcome after myocardial infarction (MI). In this study we aimed to assess the impact of LA function as a predictor of exercise capacity through speckle tracking echocardiography. Methods: A total of 94 patients (mean age 54.8 +/- 11.0 years; 82% male) were enrolled one month after MI. Echocardiography was used to assess LA volumes and various indices of LA conduit, contraction and reservoir function. LA deformation was assessed by two-dimensional speckle tracking to calculate strain and strain rate at different phases of the cardiac cycle. Exercise capacity was assessed by oxygen uptake (VO2) on cardiopulmonary exercise testing. Results: Increased LA volumes, especially LA volume before atrial contraction, were correlated with reduced peak VO2 and reduced VO2 at anaerobic threshold. Decreased peak VO2 was associated with reduced LA conduit function (p=0.24; p=0.02), but not with LA booster function (p=-0.07; p=0.53). Lower peak atrial longitudinal strain was associated with worse exercise capacity (p=0.24; p=0.02). Conclusions: After MI, increased LA volumes were markers of decreased functional capacity that was associated with decreased LA conduit function, but not with LA contractile function. In these patients, LA longitudinal strain analysis may be useful to predict reduced exercise capacity. (C) 2018 Sociedade Portuguesa de Cardiologia. Published by Elsevier Espana, S.L.U.This work was supported by the Portuguese Foundation for Science and Technology grants PEst-C/SAU/UI0051/2011 and EXCL/BIM-MEC/0055/2012 through the Cardiovascular R&D Unit and by European Commission grant FP7-Health-2010; MEDIA-261409

Caracterização dos argissolos amarelos com adição de resíduos de madeira: uma alternativa de uso como cobertura em solos da Amazônia paraense.

Em solos altamente intemperizados, como ocorre nos trópicos, a razão de seu empobrecimento está relacionada à lixiviação dos nutrientes das camadas superficiais. Uma alternativa para minimizar esta perda de nutrientes seria a utilização de coberturas orgânicas verdes ou mortas (mulch) nestes solos. Nesse sentido, com o intuito de caracterizar os aspectos morfológicos, físicos e químicos dos solos com e sem adição de resíduos de madeira como cobertura, sob as culturas de paricá (Schizolobium amazonicum) e pupunha (Bactris gasipaes), foram selecionados e coletados 32 amostras de 4 perfis de solo das áreas de plantio de paricá e pupunha com e sem adição de resíduos de madeira. A utilização de resíduos de madeira como cobertura favoreceu a diminuição da densidade, com valores entre 1,19 a 1,33 kg.dm-3 para os solos com adição de resíduos, e de 1,19 a 1,67 kg.dm-3 para os solos sem adição. A mesma influência pode ser percebida no aumento da porosidade nos solos com adição de material, com valores de 0,48 a 0,46 m3.m-3 nos horizontes superficiais, enquanto que os solos sem resíduos demonstraram resultados de 0,35 a 0,38 m3.m-3. Os resultados de pH em água, nos solos com cobertura de resíduos de madeira, variaram de 4,6 a 6 e, os solos sem adição, de 4,6 a 5,2, podendo ser verificado que a adição de resíduos de madeira favoreceu o aumento do pH no solo. Os valores mais elevados para a saturação de bases foram observados também para os solos com utilização de resíduos de madeira como cobertura, cujos valores variaram entre 26% a 54%, enquanto que os perfis sem adição de material orgânico apresentaram variação entre 26% a 39%. O uso adequado de resíduos de madeira no solo desempenhou papel importante na disponibilidade de alguns nutrientes, como o cálcio e o magnésio, e diminuiu a acidez dos solos. Assim, a utilização de resíduos de madeira como cobertura no solo em sistemas agroflorestais é satisfatória por permitir uma destinação adequada para estes materiais, além de melhorar as condições ambientais dos solos amazônicos

Determination of the neutron star mass-radii relation using narrow-band gravitational wave detector

The direct detection of gravitational waves will provide valuable astrophysical information about many celestial objects. The most promising sources of gravitational waves are neutron stars and black holes. These objects emit waves in a very wide spectrum of frequencies determined by their quasi-normal modes oscillations. In this work we are concerned with the information we can extract from f and p$_I$-modes when a candidate leaves its signature in the resonant mass detectors ALLEGRO, EXPLORER, NAUTILUS, MiniGrail and SCHENBERG. Using the empirical equations, that relate the gravitational wave frequency and damping time with the mass and radii of the source, we have calculated the radii of the stars for a given interval of masses $M$ in the range of frequencies that include the bandwidth of all resonant mass detectors. With these values we obtain diagrams of mass-radii for different frequencies that allowed to determine the better candidates to future detection taking in account the compactness of the source. Finally, to determine which are the models of compact stars that emit gravitational waves in the frequency band of the mass resonant detectors, we compare the mass-radii diagrams obtained by different neutron stars sequences from several relativistic hadronic equations of state (GM1, GM3, TM1, NL3) and quark matter equations of state (NJL, MTI bag model). We verify that quark stars obtained from MIT bag model with bag constant equal to 170 MeV and quark of matter in color-superconductivity phase are the best candidates for mass resonant detectors.Comment: 10 pages and 3 figure

Major histocompatibility complex class I associations in iron overload: evidence for a new link between the HFE H63D mutation, HLA‐A29, and non‐classical forms of hemochromatosis.

Immunogenetics. 1998 Apr;47(5):404-10. Major histocompatibility complex class I associations in iron overload: evidence for a new link between the HFE H63D mutation, HLA-A29, and non-classical forms of hemochromatosis. Porto G, Alves H, Rodrigues P, Cabeda JM, Portal C, Ruivo A, Justiça B, Wolff R, De Sousa M. Santo António General Hospital, Largo do Prof. Abel Salazar, no.1, P-4050 Porto, Portugal. Abstract The present study is an analysis of the frequencies of HFE mutations in patients with different forms of iron overload compared with the frequencies found in healthy subjects from the same region. The frequencies of HLA-A and -B antigens and HLA haplotypes were also analyzed in the same subjects. The study population included: 71 healthy individuals; 39 genetically and clinically well-characterized patients with genetic hemochromatosis (HH); and 25 patients with non-classical forms of iron overload (NCH), excluding secondary hemochromatosis. All subjects were HLA-typed and HFE-genotyped by the oligonucleotide ligation assay (OLA). The gene frequencies found for the C282Y and H63D mutations of HFE were respectively: 0.03 and 0.23 in healthy individuals, 0.86 and 0.04 in HH patients, and 0.08 and 0.48 in NCH patients. An expected significant association between HH and HLA-A3 was observed, which was found to be in linkage disequilibrium with the C282Y mutation. A new association was seen, however, between HLA-A29 and NCH, in linkage disequilibrium with the H63D mutation. Again as expected, the HLA-B antigen B7 was associated with HH in linkage disequilibrium with HLA-A3. In addition, the HLA-B antigen B44 was found to be associated with NCH but not in linkage disequilibrium with either A29 or the H63D mutation. In conclusion, a new association of the HFE H63D mutation with forms of hemochromatosis other than HH and a new association between the HLA phenotype A29 and the HFE H63D mutation were found in the same patients. These findings reinforce evidence for the involvement of the major histocompatibility class I in iron metabolism, supporting the notion of a physiological role for the immunological system in the regulation of iron load. PMID: 9510559 [PubMed - indexed for MEDLINE

Características químicas de um gleissolo sob diferentes sistemas de uso, nas margens do rio Guamá, Belém, Pará.

Foram estudados os efeitos do uso do solo sobre a fertilidade, em Gleissolo sob três diferentes sistemas de manejo. As coletas foram feitas antes do período chuvoso nos seguintes sistemas de manejo: área cultivada com arroz (Oriza sativa L.) há aproximadamente 40 anos, com algumas interrupções ao longo deste período, com o cultivo algumas vezes mecanizado e uso de aração e gradagem; área sob pastagem de canarana erecta lisa (Echinochloa pyramidalis Hitch.), formada há cerca de 20 anos sem uso de adubações ou calagens; e área sob vegetação natural de floresta típica das áreas de várzea alta. As amostras de solo foram coletadas em dez pontos a partir de um transecto nas áreas, em quatro profundidades 0-10, 10-20, 20-30 e 30-40 cm. Os resultados demonstraram que o solo em condições naturais, de modo geral, apresentou atributos químicos que variaram de bons a muito bons, o que demonstra um grande potencial para o uso agrícola. O cultivo agrícola dos solos das várzeas do rio Guamá provocou uma redução da concentração de P e de K. O sistema de uso com pastagem apresentou maior sustentabilidade da fertilidade do que o sistema sob cultivo com arroz, visto que, além da melhoria das características químicas, a matéria orgânica elevou-se, também, em relação ao sistema natural