4,901 research outputs found
Heat Capacity Effects Associated with the Hydrophobic Hydration and Interaction of Simple Solutes: A Detailed Structural and Energetical Analysis Based on MD Simulations
We examine the SPCE and TIP5P water models to study heat capacity effects
associated with the hydrophobic hydration and interaction of Xenon particles.
We calculate the excess chemical potential for Xenon employing the Widom
particle insertion technique. The solvation enthalpy and excess heat capacity
is obtained from the temperature dependence of the chemical potentials and,
alternatively, directly by Ewald summation, as well as a reaction field based
method. All three different approaches provide consistent results. The reaction
field method allows a separation of the individual components to the heat
capacity of solvation into solute/solvent and solvent/solvent parts, revealing
the solvent/solvent part as the dominating contribution. A detailed spacial
analysis of the heat capacity of the water molecules around a pair of Xenon
particles at different separations reveals that the enhanced heat capacity of
the water molecules in the bisector plane between two Xenon atoms is
responsible for the maximum of the heat capacity observed at the desolvation
barrier, recently reported by Shimizu and Chan ({\em J. Am. Chem. Soc.},{\bf
123}, 2083--2084 (2001)). The about 60% enlarged heat capacity of water in the
concave part of the joint Xenon-Xenon hydration shell is the result of a
counterplay of strengthened hydrogen bonds and an enhanced breaking of hydrogen
bonds with increasing temperature. Differences between the two models
concerning the heat capacity in the Xenon-Xenon contact state are attributed to
the different water model bulk heat capacities, and to the different spacial
extension of the structure effect introduced by the hydrophobic particles.
Similarities between the different states of water in the joint Xenon-Xenon
hydration shell and the properties of stretched water are discussed.Comment: 14 pages, 16 figures, twocolumn revte
Education for Growth in Sweden and the World
This paper tries to reconcile evidence on the effect of schooling on income and on GDP growth from the microeconometric and empirical macro growth literatures. Much microeconometric evidence suggests that education is an important causal determinant of income for individuals within countries as diverse as Sweden and the United States. At a national level, however, recent studies have found that increases in educational attainment are unrelated to economic growth. This finding is shown to be a spurious result of the extremely high rate of measurement error in first-differenced cross-country education data. After accounting for measurement error, the effect of changes in educational attainment on income growth in cross-country data is at least as great as microeconometric estimates of the rate of return to years of schooling. We also investigate another finding of the macro growth literature -- that economic growth depends positively on the initial stock of human capital. We find that the effect of the initial level of education on growth is sensitive to the econometric assumptions that are imposed on the data (e.g., constant-coefficient assumption), as well as to the other covariates included in the model. Perhaps most importantly, we find that the initial level of education does not appear to have a significant effect on economic growth among OECD countries. The conclusion comments on policy implications for Sweden based on the human capital literature.
Education for Growth: Why and For Whom?
This paper tries to reconcile evidence from the microeconometric and empirical macro growth literatures on the effect of schooling on income and GDP growth. Much microeconometric evidence suggest that education is an important causal determinant of income for individuals within countries. At a national level, however, recent studies have found that increases in educational attainment are unrelated to economic growth. This finding appears to be a spurious result of the extremely high rate of measurement error in first-differenced cross-country education data. After accounting for measurement error, the effect of changes in educational attainment on income growth in cross-country data is at least as great as microeconometric estimates of the rate of return to years of schooling. Another finding of the macro growth literature - that economic growth depends positively on the initial stock of human capital - is shown to result from imposing linearity and constant-coefficient assumptions on the estimates. These restrictions are often rejected by the data, and once either assumption is relaxed the initial level of education has little effect on economic growth for the average country.
Services and the new economic landscape
The growth of the service economy in advanced and developing economies has created what are now being referred to as New Economic Landscapes. These landscapes are not only built forms, they are job generators and new sources of economic power for the regions that house them. This service economy is variegated, with differing sources of demand, and varying geographies of supply. A dynamic element in this mileaux is the evolving producer service complex--an amalgum of financial, business, legal, and professional services, which have had rapid expansion in most parts of the global economy. Existing conceptual paradigms in regional science have not fully acknowledged the manifold importances of The New Economic Landscape--they have essentially danced around it. In this paper we zero in on the central role of services, as well as primary and secondary industries, in the current economic era, relating on the one hand the expansion of information-oriented producer services to patterns of evolution in goods producing primary and secondary industries, as well as placing these dynamic producer service sectors in context of the ongoing expansion of the larger service sector. The goal of this paper is to make clear the regional development implications of the complex processes of service industry development occuring globally, while simultaneously speaking to the implications of this transformation for regions and theory in regional science. In this regard we build on recent conceptualizations of the role of industrial and information networks, economic underpinnings of regional economies, new perspectives on entrepreneurial activity, and behaviors which we have documented are important to the success of service industries on the New Economic Landscape. In doing so, we take advantage of and extend conceptualizations which have been developed largely in management science as they bear on firm-level performance, and marry these ideas with the emerging literature on the importance of the vital position of regions in the so-called global economy.
Selection of the principal cause of death : studies on the basis of mortality statistics for rheumatoid arthritis
The official statistics of Sweden for 1971-75 show a 2.7-fold increase in mortality for men and a 3.0-fold increase for women attributed to rheumatoid arthritis (RA) as the underlying cause of death.
In order to investigate the basis of this observed increase, all
death certificates for 1971 and 1975 with a diagnosis of RA (N=1224)
were studied. All information was re-coded according to the original
entry on the death certificates.
The aims of the study were to seek an explanation of the observed
increase by investigating the National Central Bureau of Statistics ' (NCBS) registration procedure, and to identify inadequacies in
the completion of death certificates and major interpretation problems facing the certifiers and coders in the reporting and registration of the causes of death.
The investigation showed that the observed increase was due to
changes in the NCBS' registration procedure: An increased tendency by
the NCBS to favour RA in the registration of the underlying cause of
death even when RA was not reported as the underlying cause on the
death certificates. Physicians had reported a slight decrease for men
and practically no change at all for women between the years when RA
was considered the underlying cause of death.
The major inadequacies identified on the certificates were (1) an
inadequate causal sequence, (2) diagnoses making the conditions
difficult or impossible to code, (3) more than one diagnosis for each
link in the causal sequence leading to death, and (4) an underlying
condition not stated in accordance with other provisions of the
official WHO instructions. The NCBS was found to have registered RA
as the underlying cause instead of physicians' stated underlying
condition (i) when RA was likely to have caused the stated underlying
condition, (ii) when the non-RA diagnosis was the only entry in part
I of the certificate and rendered an incomplete description of the
fatal course of events, (iii) when the non-RA condition could only be
classified by a rest-category code of the International Classification of Diseases (ICD) , and (iv) when the non-RA condition was
considered 'trivial'.
The NCBS' increased registration of RA as the underlying cause of
death in the period examined could not be explained by inadequately
made out death certificates, nor by a strict application of the rules
for coders on selection of the underlying cause of death issued in
the ICD.
Several interpretation problems were identified of significance to
cause-of-death statistics in general and different interpretations
were discussed. Some of these problems were caused by inadequacies on the certificates. Others concerned incompleteness, ambiguities, and
manifold meanings of the basic concepts and rules governing the
reporting and registration of causes of death
TB168: Time-Series Analysis of Maine Stumpage Prices
The authors of this bulletin analyze price series for stumpage in Maine. For each available species and product group (sawlogs, pulpwood), they test for stationarity and fit autoregressive integrated moving average (ARIMA ) models to the data based on preliminary diagnostics. They then perform in-sample and out-of-sample price forecasts. The central objective or this work is to characterize the processes for Maine stumpage prices in order to identify opportunities for using reservation price policies to increase timber and land values. These results are of particular value to nonindustrial timber growers for use in scheduling harvests.https://digitalcommons.library.umaine.edu/aes_techbulletin/1044/thumbnail.jp
Metastability of life
The physical idea of the natural origin of diseases and deaths has been
presented. The fundamental microscopical reason is the destruction of any
metastable state by thermal activation of a nucleus of a nonreversable change.
On the basis of this idea the quantitative theory of age dependence of death
probability has been constructed. The obtained simple Death Laws are very
accurately fulfilled almost for all known diseases.Comment: 3 pages, 4 figure
Corrfunc: Blazing fast correlation functions with AVX512F SIMD Intrinsics
Correlation functions are widely used in extra-galactic astrophysics to
extract insights into how galaxies occupy dark matter halos and in cosmology to
place stringent constraints on cosmological parameters. A correlation function
fundamentally requires computing pair-wise separations between two sets of
points and then computing a histogram of the separations. Corrfunc is an
existing open-source, high-performance software package for efficiently
computing a multitude of correlation functions. In this paper, we will discuss
the SIMD AVX512F kernels within Corrfunc, capable of processing 16 floats or 8
doubles at a time. The latest manually implemented Corrfunc AVX512F kernels
show a speedup of up to relative to compiler-generated code for
double-precision calculations. The AVX512F kernels show
speedup relative to the AVX kernels and compare favorably to a theoretical
maximum of . In addition, by pruning pairs with too large of a minimum
possible separation, we achieve a speedup across all the SIMD
kernels. Such speedups highlight the importance of programming explicitly with
SIMD vector intrinsics for complex calculations that can not be efficiently
vectorized by compilers. Corrfunc is publicly available at
https://github.com/manodeep/Corrfunc/.Comment: Paper II for the Corrfunc software package, paper I is on arXiv here:
arXiv:1911.03545. Appeared in the refereed proceedings for the "Second
Workshop on Software Challenges to Exascale Computing
- …