816 research outputs found

    A comparative analysis of different future weather data for building energy performance simulation

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    The building energy performance pattern is predicted to be shifted in the future due to climate change. To analyze this phenomenon, there is an urgent need for reliable and robust future weather datasets. Several ways for estimating future climate projection and creating weather files exist. This paper attempts to comparatively analyze three tools for generating future weather datasets based on statistical downscaling (WeatherShift, Meteonorm, and CCWorldWeatherGen) with one based on dynamical downscaling (a future-typical meteorological year, created using a high-quality reginal climate model). Four weather datasets for the city of Rome are generated and applied to the energy simulation of a mono family house and an apartment block as representative building types of Italian residential building stock. The results show that morphed weather files have a relatively similar operation in predicting the future comfort and energy performance of the buildings. In addition, discrepancy between them and the dynamical downscaled weather file is revealed. The analysis shows that this comes not only from using different approaches for creating future weather datasets but also by the building type. Therefore, for finding climate resilient solutions for buildings, care should be taken in using different methods for developing future weather datasets, and regional and localized analysis becomes vital

    Trend-based analysis of a population model of the AKAP scaffold protein

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    We formalise a continuous-time Markov chain with multi-dimensional discrete state space model of the AKAP scaffold protein as a crosstalk mediator between two biochemical signalling pathways. The analysis by temporal properties of the AKAP model requires reasoning about whether the counts of individuals of the same type (species) are increasing or decreasing. For this purpose we propose the concept of stochastic trends based on formulating the probabilities of transitions that increase (resp. decrease) the counts of individuals of the same type, and express these probabilities as formulae such that the state space of the model is not altered. We define a number of stochastic trend formulae (e.g. weakly increasing, strictly increasing, weakly decreasing, etc.) and use them to extend the set of state formulae of Continuous Stochastic Logic. We show how stochastic trends can be implemented in a guarded-command style specification language for transition systems. We illustrate the application of stochastic trends with numerous small examples and then we analyse the AKAP model in order to characterise and show causality and pulsating behaviours in this biochemical system

    Observation of long-lived polariton states in semiconductor microcavities across the parametric threshold

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    The excitation spectrum around the pump-only stationary state of a polariton optical parametric oscillator (OPO) in semiconductor microcavities is investigated by time-resolved photoluminescence. The response to a weak pulsed perturbation in the vicinity of the idler mode is directly related to the lifetime of the elementary excitations. A dramatic increase of the lifetime is observed for a pump intensity approaching and exceeding the OPO threshold. The observations can be explained in terms of a critical slowing down of the dynamics upon approaching the threshold and the following onset of the soft Goldstone mode

    A Ordem de Cristo no contexto de uma economia de mercês. Critérios de provimento de cargos e ofícios nos séculos XVII e XVIII: o caso da capitania do Espírito Santo

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    Neste trabalho, partimos do conceito original de ordem religioso-militar e dissertamos sobre a história da Ordem de Cristo, a qual identificamos e descrevemos as origens medievais como ordem religioso-militar e a sua criação ou fundação por necessidade estratégica da monarquia portuguesa para proteger e manter o patrimônio templário no território português. Seguimos para a descrição de um panorama do Brasil colonial inserido no Império ultramarino português, as suas estruturas e práticas político-administrativas com ênfase no sistema de capitanias hereditárias e do governo-geral criados pela monarquia portuguesa. Apresentamos a discussão da dualidade MetrópoleColônia e a busca do controle político e administrativo periférico pelo centro do poder português. Em continuação, abordamos a consolidação de uma economia de mercês, que atuava na seleção de servidores para a burocracia no reino e nas conquistas ultramarinas portuguesas. Assim, na época moderna desenha-se um novo modelo de cavaleiro das ordens militares que se definia como servidor destacado do rei, limpo de sangue e com cabedal que lhe permitisse não sujar as mãos com trabalho e então o interesse nas ordens militares, em particular pelo hábito da Ordem de Cristo, generaliza-se por toda a sociedade portuguesa. Concluindo o trabalho, caracterizamos a formação da capitania do Espírito Santo e a partir de fontes manuscritas e impressas que abarcam os séculos XVII e XVIII dissertamos sobre as inflexões de uma economia de mercês que se consolidava e sobre a presença da Ordem de Cristo em um contexto regional de provimento de cargos e ofícios na capitania do Espírito Santo

    subtee: An R Package for Subgroup Treatment Effect Estimation in Clinical Trials

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    The investigation of subgroups is an integral part of randomized clinical trials. Exploration of treatment effect heterogeneity is typically performed by covariate-adjusted analyses including treatment-by-covariate interactions. Several statistical techniques, such as model averaging and bagging, were proposed recently to address the problem of selection bias in treatment effect estimates for subgroups. In this paper, we describe the subtee R package for subgroup treatment effect estimation. The package can be used for all commonly encountered type of outcomes in clinical trials (continuous, binary, survival, count). We also provide additional functions to build the subgroup variables to be used and to plot the results using forest plots. The functions are demonstrated using data from a clinical trial investigating a treatment for prostate cancer with a survival endpoint

    Vortex and half-vortex dynamics in a spinor quantum fluid of interacting polaritons

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    Spinorial or multi-component Bose-Einstein condensates may sustain fractional quanta of circulation, vorticant topological excitations with half integer windings of phase and polarization. Matter-light quantum fluids, such as microcavity polaritons, represent a unique test bed for realising strongly interacting and out-of-equilibrium condensates. The direct access to the phase of their wavefunction enables us to pursue the quest of whether half vortices ---rather than full integer vortices--- are the fundamental topological excitations of a spinor polariton fluid. Here, we are able to directly generate by resonant pulsed excitations, a polariton fluid carrying either the half or full vortex states as initial condition, and to follow their coherent evolution using ultrafast holography. Surprisingly we observe a rich phenomenology that shows a stable evolution of a phase singularity in a single component as well as in the full vortex state, spiraling, splitting and branching of the initial cores under different regimes and the proliferation of many vortex anti-vortex pairs in self generated circular ripples. This allows us to devise the interplay of nonlinearity and sample disorder in shaping the fluid and driving the phase singularities dynamicsComment: New version complete with revised modelization, discussion and added material. 8 pages, 7 figures. Supplementary videos: https://drive.google.com/folderview?id=0B0QCllnLqdyBfmc2ai0yVF9fa2g2VnZodGUwemVkLThBb3BoOVRKRDJMS2dUdjlZdkRTQk

    Modelling the influence of shielding on physical and biological organ doses.

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    Distributions of "physical" and "biological" dose in different organs were calculated by coupling the FLUKA MC transport code with a geometrical human phantom inserted into a shielding box of variable shape, thickness and material. While the expression "physical dose" refers to the amount of deposited energy per unit mass (in Gy), "biological dose" was modelled with "Complex Lesions" (CL), clustered DNA strand breaks calculated in a previous work based on "event-by-event" track-structure simulations. The yields of complex lesions per cell and per unit dose were calculated for different radiation types and energies, and integrated into a version of FLUKA modified for this purpose, allowing us to estimate the effects of mixed fields. As an initial test simulation, the phantom was inserted into an aluminium parallelepiped and was isotropically irradiated with 500 MeV protons. Dose distributions were calculated for different values of the shielding thickness. The results were found to be organ-dependent. In most organs, with increasing shielding thickness the contribution of primary protons showed an initial flat region followed by a gradual decrease, whereas secondary particles showed an initial increase followed by a decrease at large thickness values. Secondary particles were found to provide a substantial contribution, especially to the biological dose. In particular, the decrease of their contribution occurred at larger depths than for primary protons. In addition, their contribution to biological dose was generally greater than that of primary protons

    Efficient Parallel Statistical Model Checking of Biochemical Networks

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    We consider the problem of verifying stochastic models of biochemical networks against behavioral properties expressed in temporal logic terms. Exact probabilistic verification approaches such as, for example, CSL/PCTL model checking, are undermined by a huge computational demand which rule them out for most real case studies. Less demanding approaches, such as statistical model checking, estimate the likelihood that a property is satisfied by sampling executions out of the stochastic model. We propose a methodology for efficiently estimating the likelihood that a LTL property P holds of a stochastic model of a biochemical network. As with other statistical verification techniques, the methodology we propose uses a stochastic simulation algorithm for generating execution samples, however there are three key aspects that improve the efficiency: first, the sample generation is driven by on-the-fly verification of P which results in optimal overall simulation time. Second, the confidence interval estimation for the probability of P to hold is based on an efficient variant of the Wilson method which ensures a faster convergence. Third, the whole methodology is designed according to a parallel fashion and a prototype software tool has been implemented that performs the sampling/verification process in parallel over an HPC architecture
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