8,867 research outputs found

    Rethinking care for the sick elderly

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    It is well established that Geriatrics and Gerontology are specialties in their own right meriting separate tertiary and primary care training.1 Health Care for the elderly also forms a newly added subject to the field of biomedical ethics.2 Demographic studies are consistently predicting the increasing proportion of "aged" members in our global population.3 Positive conceptions of 'healthy aging' are rightly displacing negative ageist perceptions that indiscriminately cast the elderly as weak, vulnerable, or incapable of self-determination.4 When, through the natural course of aging or due to illness or injury, body or mind begin to fail, a legitimate need for intervention - and care - will arise. In this article we discuss what is morally justified for the elderly population and recommend changes necessary in Malta especially in view of the established postwar rise in the elderly population. 5 to which Malta has been no exception. The President of the Malta College of Family Doctors is of the opinion that, "As medical technology continues to develop and new treatments and health care costs escalate, governments all over the world must devise more morally explicit principles whereby health care resources are allocated". He also points out that there exist dilemmas at sectorial levels where different groups of people, with different special needs, may feel disadvantaged. The elderly, for example, he says have less priority than the young in getting `life-saving cardiac treatment', whilst benefiting from other services helping them to remain active members of society.6 No one doubts that the institutions that were available in Malta for the elderly until a few years ago left much to be desired. The phrase "Tax-Xjuh" for the elderly was associated with either "tal-Frankuni" (Mount Carmel Hospital) for the psychiatrically ill or with "L-Imgieret" (St. Vincent De Paul Residence) and many were the elderly who shied away from wanting to spend the last few years of their life in such institutions. Although changes have been recently implemented to improve the quality of care and the quality of the environment in these institutions, much still needs to be done.peer-reviewe

    Parallel resampling in the particle filter

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    Modern parallel computing devices, such as the graphics processing unit (GPU), have gained significant traction in scientific and statistical computing. They are particularly well-suited to data-parallel algorithms such as the particle filter, or more generally Sequential Monte Carlo (SMC), which are increasingly used in statistical inference. SMC methods carry a set of weighted particles through repeated propagation, weighting and resampling steps. The propagation and weighting steps are straightforward to parallelise, as they require only independent operations on each particle. The resampling step is more difficult, as standard schemes require a collective operation, such as a sum, across particle weights. Focusing on this resampling step, we analyse two alternative schemes that do not involve a collective operation (Metropolis and rejection resamplers), and compare them to standard schemes (multinomial, stratified and systematic resamplers). We find that, in certain circumstances, the alternative resamplers can perform significantly faster on a GPU, and to a lesser extent on a CPU, than the standard approaches. Moreover, in single precision, the standard approaches are numerically biased for upwards of hundreds of thousands of particles, while the alternatives are not. This is particularly important given greater single- than double-precision throughput on modern devices, and the consequent temptation to use single precision with a greater number of particles. Finally, we provide auxiliary functions useful for implementation, such as for the permutation of ancestry vectors to enable in-place propagation.Comment: 21 pages, 6 figure

    Product complexity, quality of institutions and the pro-trade effect of immigrants

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    The paper assesses the trade-creating impact of foreign-born residents on the international imports and exports of the French regions where they are settled. The pro-trade effect of immigrants is investigated along two intertwined dimensions: the complexity of traded goods and the quality of institutions in partner countries. The trade-enhancing impact of immigrants is, on average, more salient when they come from a country with weak institutions. However, this positive impact is especially large on the imports of simple products. When we turn to complex goods, for which the information channel conveyed by immigrants is the most valuable, immigration enhances imports regardless of the quality of institutions in the partner country. Regarding exports, immigrants substitute for weak institutions on both simple and complex goods.trade ; immigration ; quality of institutions ; product complexity ; gravity

    PRODUCT COMPLEXITY, QUALITY OF INSTITUTIONS AND THE PRO-TRADE EFFECT OF IMMIGRANTS

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    The paper assesses the trade-creating impact of foreign-born residents on the international imports and exports of the French regions where they are settled. The pro-trade effect of immigrants is investigated along two intertwined dimensions: the complexity of traded goods and the quality of institutions in partner countries. The trade-enhancing impact of immigrants is, on average, more salient when they come from a country with weak institutions. However, this positive impact is especially large on the imports of simple products. When we turn to complex goods, for which the information channel conveyed by immigrants is the most valuable, immigration enhances imports regardless of the quality of institutions in the partner country. Regarding exports, immigrants substitute for weak institutions on both simple and complex goods.MAUP; concentration; agglomeration; wage equations; gravity

    Deterministic construction of nodal surfaces within quantum Monte Carlo: the case of FeS

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    In diffusion Monte Carlo (DMC) methods, the nodes (or zeroes) of the trial wave function dictate the magnitude of the fixed-node (FN) error. Within standard DMC implementations, they emanate from short multideterminant expansions, \textit{stochastically} optimized in the presence of a Jastrow factor. Here, following a recent proposal, we follow an alternative route by considering the nodes of selected configuration interaction (sCI) expansions built with the CIPSI (Configuration Interaction using a Perturbative Selection made Iteratively) algorithm. In contrast to standard implementations, these nodes can be \textit{systematically} and \textit{deterministically} improved by increasing the size of the sCI expansion. The present methodology is used to investigate the properties of the transition metal sulfide molecule FeS. This apparently simple molecule has been shown to be particularly challenging for electronic structure theory methods due to the proximity of two low-energy quintet electronic states of different spatial symmetry. In particular, we show that, at the triple-zeta basis set level, all sCI results --- including those extrapolated at the full CI (FCI) limit --- disagree with experiment, yielding an electronic ground state of 5Σ+^{5}\Sigma^+ symmetry. Performing FN-DMC simulation with sCI nodes, we show that the correct 5Δ^{5}\Delta ground state is obtained if sufficiently large expansions are used. Moreover, we show that one can systematically get accurate potential energy surfaces and reproduce the experimental dissociation energy as well as other spectroscopic constants.Comment: 8 pages, 2 figure and 4 table

    Hybrid stochastic-deterministic calculation of the second-order perturbative contribution of multireference perturbation theory

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    A hybrid stochastic-deterministic approach for computing the second-order perturbative contribution E(2)E^{(2)} within multireference perturbation theory (MRPT) is presented. The idea at the heart of our hybrid scheme --- based on a reformulation of E(2)E^{(2)} as a sum of elementary contributions associated with each determinant of the MR wave function --- is to split E(2)E^{(2)} into a stochastic and a deterministic part. During the simulation, the stochastic part is gradually reduced by dynamically increasing the deterministic part until one reaches the desired accuracy. In sharp contrast with a purely stochastic MC scheme where the error decreases indefinitely as t−1/2t^{-1/2} (where tt is the computational time), the statistical error in our hybrid algorithm displays a polynomial decay ∌t−n\sim t^{-n} with n=3−4n=3-4 in the examples considered here. If desired, the calculation can be carried on until the stochastic part entirely vanishes. In that case, the exact result is obtained with no error bar and no noticeable computational overhead compared to the fully-deterministic calculation. The method is illustrated on the F2_2 and Cr2_2 molecules. Even for the largest case corresponding to the Cr2_2 molecule treated with the cc-pVQZ basis set, very accurate results are obtained for E(2)E^{(2)} for an active space of (28e,176o) and a MR wave function including up to 2×1072 \times 10^7 determinants.Comment: 8 pages, 5 figure

    Dots to boxes: Do the size and shape of spatial units jeopardize economic geography estimations?

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    This paper evaluates, in the context of economic geography estimates, the magnitude of the distortions arising from the choice of zoning system, which is also known as the Modifiable Areal Unit Problem (MAUP). We consider three standard economic geography exercises (the analysis of spatial concentration, agglomeration economies, and trade determinants), using various French zoning systems differentiated according to the size and shape of spatial units, which are the two main determinants of the MAUP. While size matters a little, shape does so much less. Both dimensions seem to be of secondary importance compared to specification issues.MAUP ; concentration ;agglomeration ;wage equations ;gravity

    DOTS TO BOXES: DO THE SIZE AND SHAPE OF SPATIAL UNITS JEOPARDIZE ECONOMIC GEOGRAPHY ESTIMATIONS?

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    This paper evaluates, in the context of economic geography estimates, the magnitude of the distortions arising from the choice of zoning system, which is also known as the Modifiable Areal Unit Problem (MAUP). We consider three standard economic geography exercises (the analysis of spatial concentration, agglomeration economies, and trade determinants), using various French zoning systems differentiated according to the size and shape of spatial units, which are the two main determinants of the MAUP. While size matters a little, shape does so much less. Both dimensions seem to be of secondary importance compared to specification issues.MAUP, concentration, agglomeration, wage equations, gravity

    Direct Numerical Simulation of structural vacillation in the transition to geostrophic turbulence

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    The onset of small-scale fluctuations around a steady convection pattern in a rotating baroclinic annulus filled with air is investigated using Direct Numerical Simulation. In previous laboratory experiments of baroclinic waves, such fluctuations have been associated with a flow regime termed Structural Vacillation which is regarded as the first step in the transition to fully-developed geostrophic turbulence.Comment: 6 page
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