Contributo para a melhoria do desempenho térmico das paredes de taipa

O uso da construção em terra remonta ao início da nossa civilização. Nas regiões do Alentejo e do Algarve existe ainda um grande número de edifícios com paredes em taipa, mas esta tecnologia tem vindo a cair em desuso desde meados do século passado. A construção em terra é altamente sustentável, já que a terra per si é um material 100% reutilizável e pode ser facilmente encontrado em quase todos os lugares do mundo. Os edifícios com paredes em taipa apresentam uma elevada inércia térmica o que, dadas as características climáticas de Portugal, beneficia o seu comportamento térmico. No entanto, seria desejável que a condutibilidade térmica da taipa fosse menor. As preocupações ambientais relativas ao consumo energético, associado ao conforto na habitação, e ao fabrico, transporte e aplicação dos materiais utilizados na construção, levou-nos a procurar novas soluções de tipologias construtivas em terra. Atendendo a estes aspetos e à melhoria da eficiência energética das habitações, neste trabalho são apresentados os resultados dos ensaios realizados em laboratório sobre novas soluções de construção em terra. O local selecionado para a recolha de amostras de terra foi Serpa. Foi feita a caracterização geotécnica do material terra e preparadas diversas composições com a incorporação de argila expandida e de regranulado de cortiça expandida. A argila expandida e o regranulado de cortiça expandida também foram escolhidos por serem isolantes térmicos produzidos a partir de matérias primas disponíveis nas regiões do Alentejo e do Algarve, regiões do nosso país com maior aptência para o uso da taipa. De maneira a caracterizar as diferentes composições sob o ponto de vista mecânico e do desempenho térmico, foram fabricados cubos com 10 cm de aresta e ensaiados de modo a se calcular a sua resistência à compressão e a sua condutibilidade térmica. Os resultados obtidos mostraram que a utilização deste tipo de tipologias construtivas em terra com a incorporação de argila expandida e de regranulado de cortiça expandida permite aumentar o seu desempenho, fazendo que seja possível adaptar esta tipologia às necessidades dos dias de hoje, nomeadamente às exigências estabelecidas pelo Regulamento das Características de Comportamento Térmico dos Edifícios (RCCTE). Os resultados desta investigação têm aplicabilidade, com as devidas adaptações, tanto em construções em taipa como em construções em adobe

Passage and freshwater habitat requirements of anadromous lampreys: Considerations for conservation and control

Understanding the relationship between a species and its habitats is important for both conservation of imperiled species and control of invasive species. For migratory species, we hypothesize that maintaining connectivity between segregated habitats is more important than improving the quality of each habitat. In the case of anadromous lampreys of conservation concern, we posit that restoring passage routes between spawning, rearing and feeding habitats will result in higher larval abundance upstream from barriers than efforts to improve quality of these freshwater habitats. To explore this hypothesis, we reviewed conservation actions for native anadromous lampreys in freshwater and found that: i) improving passage between habitats results in immediate and quantifiable increases in larval abundance, ii) anadromous lampreys are capable of existing in suboptimal habitats, and iii) small reservoirs of production drive rapid expansion when anadromous lampreys are released from passage constraints. Hence, maintaining habitat connectivity is clearly crucial for conservation of anadromous lampreys. There are fewer examples of improvements to freshwater habitat that increased larval lamprey abundance, perhaps because lampreys are rarely the focus of these efforts. However, habitat limitations such as stream de-watering, chemical pollution, and scour occur and will likely be exacerbated by climate change. Documenting habitat actions that reverse these problems may provide evidence for the merits of lamprey-specific habitat improvement. Our observations are relevant to sea lamprey control in the Great Lakes because barriers and chemical treatment are key instruments of population regulation, and can be strategically deployed to limit production

Bounds on Relativistic Deformed Kinematics from the Physics of the Universe Transparency

We analyze the kinematics of electron-positron production in a photon-photon interaction when one has a modification of the special relativistic kinematics as a power expansion in the inverse of a new high-energy scale. We derive the equation for the threshold energy of this reaction to first order in this expansion, including the effects due to a modification of the energy-momentum conservation equation. In contrast with the Lorentz invariance violation case, a scale of the order of a few TeV is found to be compatible with the observations of very high-energy cosmic gamma rays in the case of a modification compatible with the relativity principle

Physics of the universe transparency in a deformed kinematics

We present a first study of the possible effects of a relativistic deformation of special relativity in the recent observations of very high-energy gamma rays by the LHAASO experiment, which has opened a new phenomenological window to study deformations in the kinematics of special relativity. Our analysis of the interaction of high-energy photons with the CMB background complements theoretical studies based on Lorentz invariance violation scenarios, while making predictions that would allow one to distinguish between a violation and a deformation of the symmetries of special relativity

A study on wear evaluation of railway wheels based on multibody dynamics and wear computation

The wear evolution of railway wheels is a very important issue in railway engineering. In the past, the reprofiling intervals of railway vehicle steel wheels have been scheduled according to designers' experience. Today, more reliable and accurate tools in predicting wheel wear evolution and wheelset lifetime can be used in order to achieve economical and safety benefits. In this work, a computational tool that is able to predict the evolution of the wheel profiles for a given railway system, as a function of the distance run, is presented. The strategy adopted consists of using a commercial multibody software to study the railway dynamic problem and a purpose-built code for managing its pre- and post-processing data in order to compute the wear. The tool is applied here to realistic operation scenarios in order to assess the effect of some service conditions on the wheel wear progression

Gravitational anomaly and fundamental forces

I present an argument, based on the topology of the universe, why there are three generations of fermions. The argument implies a preferred gauge group of SU(5), but with SO(10) representations of the fermions. The breaking pattern SU(5) to SU(3)xSU(2)xU(1) is preferred over the pattern SU(5) to SU(4)xU(1). On the basis of the argument one expects an asymmetry in the early universe microwave data, which might have been detected already.Comment: Contribution to the 2nd School and Workshop on Quantum Gravity and Quantum Geometry. Corfu, september 13-20 2009. 10 page

Factors Affecting Embryo Recovery Rate, Quality, and Diameter in Andalusian Donkey Jennies

Embryo transfer and the vitrification of embryos could be used for the conservation and recovery of endangered donkey breeds. It is important to develop techniques that optimize recovery rates and the cryotolerance of donkey embryos. This study evaluates factors affecting the recovery rate, quality, and diameter of embryos obtained from donor jennies as a starting point for the use of vitrification and embryo transfer in the conservation of the Andalusian donkey. A total of 100 embryos were recovered out of 124 estrous cycles (80.6%). The donor jenny affected the rates of positive flushings (PFR; p = 0.040) and embryo recovery (ERR; p < 0.05) as well as embryo quality (p = 0.004). ERR was also affected by the number of flushings (p < 0.001), donor age (p < 0.05), successive cycle within donor (p < 0.001), and jacks (p < 0.05). Number of flushings (p < 0.001) and jack (p < 0.05) had a significant effect on PFR, whereas the day of flushing influenced the developmental stage (p < 0.001), embryo quality (p < 0.05), and diameter of embryos (p < 0.001). The number of flushings significantly influenced the diameter (p = 0.038) and embryo developmental stage (p = 0.001), whereas the developmental stage was statistically different between herds (p = 0.020). The factors influencing the success of this assisted reproductive technique were donor jenny, donor age, successive cycle within donor, day of flushing, number of flushings, and jack. The identification of these key points is crucial to achieve a higher efficiency of embryo transfer and vitrification processes, before considering their application in the conservation of endangered donkey breeds

Associação independente da variante rs1333049, no locus 9p21, com a doença coronária, numa população portuguesa

Funding: This study was supported by the European Regional Development Fund’s Operational Programme for the Enhancement of Economic Potential and Territorial Cohesion for the Autonomous Region of Madeira (INTERVIR+).Introduction: Recent genome-wide association studies have identified single-nucleotide polymorphisms (SNPs) at the 9p21 locus as risk factors for coronary artery disease (CAD). Among them, the SNP rs1333049 has demonstrated a consistent association with CAD, which has been successfully replicated in several populations. Aim: To investigate whether the SNP rsl333049 located on the 9p21 chromosome is an independent risk factor for CAD in a Portuguese population. Methods: We performed a case-control study which included 1406 individuals, 723 consecutive coronary patients (mean age 53.7±8.9 years, 79.9% male) and 683 controls without coronary disease (mean age 53.3±10.5 years, 73.9% male). Cases and controls were selected so as not to be significantly different in terms of gender and age. We studied the SNP rs1333049 at the 9p21 locus in all individuals, using standard PCR combined with the TaqMan technique (Applied Biosystems). The allelic and genotype distribution (C/G), odds ratios and corresponding confidence intervals for CAD risk were determined. A forward Wald logistic regression analysis model was constructed, adjusted for age, gender, conventional risk factors, biochemical markers and the genotypes under study, in order to determine which variables were linked significantly and independently with CAD. Results: The C allele was found in 60% of the CAD patients and 53% of the controls, with OR=1.33; p=0.0002. The CC genotype appeared in 35.7% of CAD patients, with OR=1.34, p=0.010. The heterozygous CG genotype was present in 48.1% of the CAD patients and 47% of the controls, and did not present vascular risk (OR=1.05, p=0.670). After logistic regression analysis, the CC genotype remained in the equation with 0R=1.7; p=0.018 and CG with OR=I.5, p=0.048. Conclusion: In the present study we replicated the coronary risk linked to the recently discovered variant rs1333049 on the 9p21 chromosome in a Portuguese population. Although the mechanism underlying the risk is still unknown, the robustness of this risk allele in risk stratification for CAD has been consistent, even in very different populations. The presence of the CC or CG genotype may thus prove to be useful for predicting the risk of developing CAD in the Portuguese population.publishersversionpublishe

Effect of oral ingestion of an extract of the herb Uncaria tomentosa on the biodistribution of sodium pertechnetate in rats

The aim of the present study was to determine the effect of the oral ingestion of an extract of the herb Uncaria tomentosa (cat's claw) on the biodistribution of the radiobiocomplex sodium pertechnetate (Na99mTcO4) in rats. The animals (male Wistar rats, 2 months old, 180-220 g), were treated (1 mL) with an U. tomentosa extract (32 mg/mL, N = 5) or 0.9% NaCl solution (control, N = 5) for 7 days. After this period, Na99mTcO4 (3.7 MBq, 0.3 mL) was injected through the ocular plexus and after 10 min the rats were killed, the organs isolated and counted in a well-gamma counter. A significant (P < 0.05) alteration in Na99mTcO4 uptake i) from 0.57 +/- 0.008 to 0.39 +/- 0.06 %ATI/organ (P < 0.05) and from 0.57 +/- 0.17 to 0.39 +/- 0.14 %ATI/g (P < 0.05) was observed in the heart, ii) from 0.07 +/- 0.02 to 0.19 +/- 0.07 %ATI/g in the pancreas, and iii) from 0.07 +/- 0.01 to 0.18 +/- 0.07 %ATI/g (P < 0.05) in muscle after treatment with this extract. Although these results were obtained with animals, caution is advisable in the interpretation of the nuclear medicine examination when the patient is using this herb. This finding is probably an example of drug interaction with a radiopharmaceutical, a fact that could lead to misdiagnosis of the examination in clinical practice with unexpected consequences for the patient

Spectral method for the time-dependent Gross-Pitaevskii equation with a harmonic trap

We study the numerical resolution of the time-dependent Gross-Pitaevskii equation, a non-linear Schroedinger equation used to simulate the dynamics of Bose-Einstein condensates. Considering condensates trapped in harmonic potentials, we present an efficient algorithm by making use of a spectral Galerkin method, using a basis set of harmonic oscillator functions, and the Gauss-Hermite quadrature. We apply this algorithm to the simulation of condensate breathing and scissors modes.Comment: 23 pages, 5 figure