579 research outputs found
Contributo para a melhoria do desempenho térmico das paredes de taipa
O uso da construção em terra remonta ao inĂcio da nossa civilização. Nas regiĂ”es do Alentejo e do Algarve existe ainda um grande nĂșmero de edifĂcios com paredes em taipa, mas esta tecnologia tem vindo a cair em desuso desde meados do sĂ©culo passado. A construção em terra Ă© altamente sustentĂĄvel, jĂĄ que a terra per si Ă© um material 100% reutilizĂĄvel e pode ser facilmente encontrado em quase todos os lugares do mundo. Os edifĂcios com paredes em taipa apresentam uma elevada inĂ©rcia tĂ©rmica o que, dadas as caracterĂsticas climĂĄticas de Portugal, beneficia o seu comportamento tĂ©rmico. No entanto, seria desejĂĄvel que a condutibilidade tĂ©rmica da taipa fosse menor. As preocupaçÔes ambientais relativas ao consumo energĂ©tico, associado ao conforto na habitação, e ao fabrico, transporte e aplicação dos materiais utilizados na construção, levou-nos a procurar novas soluçÔes de tipologias construtivas em terra. Atendendo a estes aspetos e Ă melhoria da eficiĂȘncia energĂ©tica das habitaçÔes, neste trabalho sĂŁo apresentados os resultados dos ensaios realizados em laboratĂłrio sobre novas soluçÔes de construção em terra. O local selecionado para a recolha de amostras de terra foi Serpa.
Foi feita a caracterização geotĂ©cnica do material terra e preparadas diversas composiçÔes com a incorporação de argila expandida e de regranulado de cortiça expandida. A argila expandida e o regranulado de cortiça expandida tambĂ©m foram escolhidos por serem isolantes tĂ©rmicos produzidos a partir de matĂ©rias primas disponĂveis nas regiĂ”es do Alentejo e do Algarve, regiĂ”es do nosso paĂs com maior aptĂȘncia para o uso da taipa.
De maneira a caracterizar as diferentes composiçÔes sob o ponto de vista mecĂąnico e do desempenho tĂ©rmico, foram fabricados cubos com 10 cm de aresta e ensaiados de modo a se calcular a sua resistĂȘncia Ă compressĂŁo e a sua condutibilidade tĂ©rmica. 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 possĂvel adaptar esta tipologia Ă s necessidades dos dias de hoje, nomeadamente Ă s exigĂȘncias estabelecidas pelo Regulamento das CaracterĂsticas de Comportamento TĂ©rmico dos EdifĂcios (RCCTE). Os resultados desta investigação tĂȘm aplicabilidade, com as devidas adaptaçÔes, tanto em construçÔes em taipa como em construçÔes em adobe
The effect of the inclusion of trunk-strengthening exercises to a multimodal exercise program on physical activity levels and psychological functioning in older adults: Secondary data analysis of a randomized controlled trial
Background
Engaging in multimodal exercise program helps mitigate age-related decrements by improving muscle size, muscle strength, balance, and physical function. The addition of trunk-strengthening within the exercise program has been shown to significantly improve physical functioning outcomes. Whether these improvements result in improved psychological outcomes associated with increased physical activity levels requires further investigation. We sought to explore whether the inclusion of trunk-strengthening exercises to a multimodal exercise program improves objectively measured physical activity levels and self-reported psychological functioning in older adults.
Method
We conducted a secondary analysis within a single-blinded parallel-group randomized controlled trial. Sixty-four healthy older (â„â60 years) adults were randomly allocated to a 12-week walking and balance exercise program with (nâ=â32) or without (nâ=â32) inclusion of trunk strengthening exercises. Each program involved 12 weeks of exercise training, followed by a 6-week walking-only program (identified as detraining). Primary outcome measures for this secondary analysis were physical activity (accelerometry), perceived fear-of-falling, and symptoms of anxiety and depression.
Results
Following the 12-week exercise program, no significant between-group differences were observed for physical activity, sedentary behaviour, fear-of-falling, or symptoms of anxiety or depression. Significant within-group improvements (adjusted mean difference [95%CI]; percentage) were observed in moderate-intensity physical activity (6.29 [1.58, 11.00] min/day;â+â26.3%) and total number of steps per min/day (0.81 [0.29 to 1.33] numbers orâ+â16.3%) in trunk-strengthening exercise group by week 12. With respect to within-group changes, participants in the walking-balance exercise group increased their moderate-to-vigorous physical activity (MVPA) (4.81 [0.06 to 9.56] min/day;â+â23.5%) and reported reduction in symptoms of depression (-0.26 [-0.49 to -0.04] points or -49%) after 12 weeks of the exercise program. The exercise-induced increases in physical activity levels in the trunk-strengthening exercise group were abolished 6-weeks post-program completion. While improvements in physical activity levels were sustained in the walking-balance exercise group after detraining phase (walking only).
Conclusions
The inclusion of trunk strengthening to a walking-balance exercise program did not lead to statistically significant between-group improvements in physical activity levels or psychological outcomes in this cohort following completion of the 12-week exercise program
Emergence of Anti-Cancer Drug Resistance: Exploring the Importance of the Microenvironmental Niche via a Spatial Model
Practically, all chemotherapeutic agents lead to drug resistance. Clinically,
it is a challenge to determine whether resistance arises prior to, or as a
result of, cancer therapy. Further, a number of different intracellular and
microenvironmental factors have been correlated with the emergence of drug
resistance. With the goal of better understanding drug resistance and its
connection with the tumor microenvironment, we have developed a hybrid
discrete-continuous mathematical model. In this model, cancer cells described
through a particle-spring approach respond to dynamically changing oxygen and
DNA damaging drug concentrations described through partial differential
equations. We thoroughly explored the behavior of our self-calibrated model
under the following common conditions: a fixed layout of the vasculature, an
identical initial configuration of cancer cells, the same mechanism of drug
action, and one mechanism of cellular response to the drug. We considered one
set of simulations in which drug resistance existed prior to the start of
treatment, and another set in which drug resistance is acquired in response to
treatment. This allows us to compare how both kinds of resistance influence the
spatial and temporal dynamics of the developing tumor, and its clonal
diversity. We show that both pre-existing and acquired resistance can give rise
to three biologically distinct parameter regimes: successful tumor eradication,
reduced effectiveness of drug during the course of treatment (resistance), and
complete treatment failure
Rede De Apoio Social, SaĂșde Mental E Qualidade De Vida: Um Estudo Transversal Na Atenção PrimĂĄria
Conselho Nacional de Desenvolvimento CientĂfico e TecnolĂłgico (CNPq)The objective of this study was to identify the association between emotional distress and social support networks with quality of life in primary care patients. This was a cross-sectional study involving 1,466 patients in the cities of SĂŁo Paulo and Rio de Janeiro, Brazil, in 2009/2010. The General Health Questionnaire, the Hospital Anxiety and Depression Scale and the brief version of the World Health Organization Quality of Life Instrument were used. The Social Support Network Index classified patients with the highest and lowest index as socially integrated or isolated. A bivariate analysis and four multiple linear regressions were conducted for each quality of life outcome. The means scores for the physical, psychological, social relations, and environment domains were, respectively, 64.7; 64.2; 68.5 and 49.1. In the multivariate analysis, the psychological domain was negatively associated with isolation, whereas the social relations and environment domains were positively associated with integration. Integration and isolation proved to be important factors for those in emotional distress as they minimize or maximize negative effects on quality of life. © 2016, Fundacao Oswaldo Cruz. All rights reserved.3212CNPq, Conselho Nacional de Desenvolvimento CientĂfico e TecnolĂłgicoConselho Nacional de Desenvolvimento CientĂfico e TecnolĂłgico (CNPq
Orbital structure of the GJ876 extrasolar planetary system, based on the latest Keck and HARPS radial velocity data
We use full available array of radial velocity data, including recently
published HARPS and Keck observatory sets, to characterize the orbital
configuration of the planetary system orbiting GJ876. First, we propose and
describe in detail a fast method to fit perturbed orbital configuration, based
on the integration of the sensitivity equations inferred by the equations of
the original -body problem. Further, we find that it is unsatisfactory to
treat the available radial velocity data for GJ876 in the traditional white
noise model, because the actual noise appears autocorrelated (and demonstrates
non-white frequency spectrum). The time scale of this correlation is about a
few days, and the contribution of the correlated noise is about 2 m/s (i.e.,
similar to the level of internal errors in the Keck data). We propose a
variation of the maximum-likelihood algorithm to estimate the orbital
configuration of the system, taking into account the red noise effects. We
show, in particular, that the non-zero orbital eccentricity of the innermost
planet \emph{d}, obtained in previous studies, is likely a result of
misinterpreted red noise in the data. In addition to offsets in some orbital
parameters, the red noise also makes the fit uncertainties systematically
underestimated (while they are treated in the traditional white noise model).
Also, we show that the orbital eccentricity of the outermost planet is actually
ill-determined, although bounded by . Finally, we investigate
possible orbital non-coplanarity of the system, and limit the mutual
inclination between the planets \emph{b} and \emph{c} orbits by
, depending on the angular position of the mutual orbital
nodes.Comment: 36 pages, 11 figures, 3 tables; Accepted to Celestial Mechanics and
Dynamical Astronom
Survival, Mortality, Causes and Places of Death in a European Huntington's Disease Prospective Cohort
Neurological Motor Disorder
Against all odds? Forming the planet of the HD196885 binary
HD196885Ab is the most "extreme" planet-in-a-binary discovered to date, whose
orbit places it at the limit for orbital stability. The presence of a planet in
such a highly perturbed region poses a clear challenge to planet-formation
scenarios. We investigate this issue by focusing on the planet-formation stage
that is arguably the most sensitive to binary perturbations: the mutual
accretion of kilometre-sized planetesimals. To this effect we numerically
estimate the impact velocities amongst a population of circumprimary
planetesimals. We find that most of the circumprimary disc is strongly hostile
to planetesimal accretion, especially the region around 2.6AU (the planet's
location) where binary perturbations induce planetesimal-shattering of
more than 1km/s. Possible solutions to the paradox of having a planet in such
accretion-hostile regions are 1) that initial planetesimals were very big, at
least 250km, 2) that the binary had an initial orbit at least twice the present
one, and was later compacted due to early stellar encounters, 3) that
planetesimals did not grow by mutual impacts but by sweeping of dust (the
"snowball" growth mode identified by Xie et al., 2010b), or 4) that HD196885Ab
was formed not by core-accretion but by the concurent disc instability
mechanism. All of these 4 scenarios remain however highly conjectural.Comment: accepted for publication by Celestial Mechanics and Dynamical
Astronomy (Special issue on EXOPLANETS
Density functional method for nonequilibrium electron transport
We describe an ab initio method for calculating the electronic structure,
electronic transport, and forces acting on the atoms, for atomic scale systems
connected to semi-infinite electrodes and with an applied voltage bias. Our
method is based on the density functional theory (DFT) as implemented in the
well tested Siesta approach (which uses non-local norm-conserving
pseudopotentials to describe the effect of the core electrons, and linear
combination of finite-range numerical atomic orbitals to describe the valence
states). We fully deal with the atomistic structure of the whole system,
treating both the contact and the electrodes on the same footing. The effect of
the finite bias (including selfconsistency and the solution of the
electrostatic problem) is taken into account using nonequilibrium Green's
functions. We relate the nonequilibrium Green's function expressions to the
more transparent scheme involving the scattering states. As an illustration,
the method is applied to three systems where we are able to compare our results
to earlier ab initio DFT calculations or experiments, and we point out
differences between this method and existing schemes. The systems considered
are: (1) single atom carbon wires connected to aluminum electrodes with
extended or finite cross section, (2) single atom gold wires, and finally (3)
large carbon nanotube systems with point defects.Comment: 18 pages, 23 figure
Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in âs = 7 TeV pp collisions with the ATLAS detector
A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fbâ1 of protonâproton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results
Jet size dependence of single jet suppression in lead-lead collisions at sqrt(s(NN)) = 2.76 TeV with the ATLAS detector at the LHC
Measurements of inclusive jet suppression in heavy ion collisions at the LHC
provide direct sensitivity to the physics of jet quenching. In a sample of
lead-lead collisions at sqrt(s) = 2.76 TeV corresponding to an integrated
luminosity of approximately 7 inverse microbarns, ATLAS has measured jets with
a calorimeter over the pseudorapidity interval |eta| < 2.1 and over the
transverse momentum range 38 < pT < 210 GeV. Jets were reconstructed using the
anti-kt algorithm with values for the distance parameter that determines the
nominal jet radius of R = 0.2, 0.3, 0.4 and 0.5. The centrality dependence of
the jet yield is characterized by the jet "central-to-peripheral ratio," Rcp.
Jet production is found to be suppressed by approximately a factor of two in
the 10% most central collisions relative to peripheral collisions. Rcp varies
smoothly with centrality as characterized by the number of participating
nucleons. The observed suppression is only weakly dependent on jet radius and
transverse momentum. These results provide the first direct measurement of
inclusive jet suppression in heavy ion collisions and complement previous
measurements of dijet transverse energy imbalance at the LHC.Comment: 15 pages plus author list (30 pages total), 8 figures, 2 tables,
submitted to Physics Letters B. All figures including auxiliary figures are
available at
http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HION-2011-02
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