1,658 research outputs found
S-matrices for spinor particles on Reissner-Nordstr\"{o}m black holes
The scattering problems arising when considering the contribution of the
topologically inequivalent configurations of the spinors on
Reissner-Nordstr\"{o}m black holes to the Hawking radiation are correctly
stated. The corresponding -matrices are described and presented in the form
convenient to numerical computations.Comment: 11 pages, LaTe
"Effects of Information Technology and Aging Work Force on Labor Demand and Technological Progress in Japanese Industries: 1980-1998"
The purpose of this paper is two-folds. First, we examine the direction and the magnitude of substitutability or complementarity between information- and communication-related capital stock and various labor inputs to know about differential impacts of information and com-munication technology on labor demand. In this way, we can obtain information about what segments of workers information and communication technology can effectively substu-tute for. Second, we estimate contribution of information- and communication-related capital stock and various labor inputs on the value-added growth of the Japanese economy in the recent turbulent era (1980s and 1990s) and explore factors determining technological progress. In particular, we investigate whether rapid accumulation of information-related capital stock has a positive effect on technological progress, examining IT externality. We also discern the effect of compositional changes in labor inputs on technological progress, examining the inflexibility issue and IT-induced technological obsolescence issue. Three remarkable facts emerge from our result with respect to substitutability/complementarity issues. First, IT capital stocks are shown to be significant substitutes for young workers with a low education level, whereas old workers with a low education level are consistently quasi-fixed in all industries under investigation. Second, IT capital stocks have complemen-tary relationship with workers with a high education level in many industries. Third, workers with a high education level and those with a low education level are substitutes. These all suggest that IT investment and human capital accumulation are of utmost importance to overcome possible shortage (in relative terms) of young workers with a low education level caused by rapidly aging population. As for IT externality, we find at first positive correlation between IT stocks and techno-logical progress in manufacturing, suggesting a strong externality effect of IT capital stocks. In the first glance it is very promising, since this suggests that this IT externality can be used for boosting productivity growth. However, the correlation is not robust. First, if non-manufacturing industries are included, the correlation vanishes. Second, if "Electrical Machinery" is excluded from the sample of manufacturing, the correlation also vanishes. Thus, we fail to discern clear-cut evidence for IT externality. Thus, the proposition that IT "revolution"can pop up productivity growth and can counter the pressure of aging population is not supported by our data, although investment in IT-producing industries is surely an important driving force for economic growth through substitution effects. As for the effect of labor force composition on the rate of technological progress, the results do not support that the "inflexible old worker" hypothesis of productivity slowdown. There is no correlation between the rate of technological progress and the ratio of old workers with low education in the total labor inputs. However, the results suggest that information technology development in the 1990s has a negative impact on the past strength of the Japanese economy: productivity increase through high-education workers' learning by doing. In manufacturing industries where Japan has been strong, the rate of technological progress in the 1980s has positive (though weak) correlation with "maturing" high-education labor force. That is, the ratio of old well-educated workers in the total labor inputs has a positive (though weak) effect on technological progress. This suggests that the increased average skill among well-educated workers due to longer experience has a positive effect to improve productivity. However, the relationship changes significantly in the 1990s, and we have rather negative relationship. The nature of technological progress apparently changed adversely.
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Linking Northern Hemisphere blocking and storm track biases in the CMIP5 climate models
The relationship between biases in Northern Hemisphere (NH) atmospheric blocking frequency and extratropical cyclone track density is investigated in 12 CMIP5 climate models to identify mechanisms underlying climate model biases and inform future model development. Biases in the Greenland blocking and summer Pacific blocking frequencies are associated with biases in the storm track latitudes while biases in winter European blocking frequency are related to the North Atlantic storm track tilt and Mediterranean cyclone density. However, biases in summer European and winter Pacific blocking appear less related with cyclone track density. Furthermore, the models with smaller biases in winter European blocking frequency have smaller biases in the cyclone density in Europe, which suggests that they are different aspects of the same bias. This is not found elsewhere in the NH. The summer North Atlantic and the North Pacific mean CMIP5 track density and blocking biases might therefore have different origins
Vsop2/Astro-G Project
We introduce a new space VLBI project, the Second VLBI Space Observatory
Program (VSOP2), following the success of the VLBI Space Observatory Program
(VSOP1). VSOP2 has 10 times higher angular resolution, up to about 40 micro
arcseconds, 10 times higher frequency up to 43 GHz, and 10 times higher
sensitivity compared to VSOP1. Then VSOP2 should become a most powerful tool to
observe innermost regions of AGN and astronomical masers. ASTRO-G is a
spacecraft for VSOP2 project constructing in ISAS/JAXA since July 2007. ASTRO-G
will be launched by JAXA H-IIA rocket in fiscal year 2012. ASTRO-G and
ground-based facilities are combined as VSOP2. To achieve the good observation
performances, we must realize new technologies. They are large precision
antenna, fast-position switching capability, new LNAs, and ultra wide-band down
link, etc.. VSOP2 is a huge observation system involving ASTRO-G, ground radio
telescopes, tracking stations, and correlators, one institute can not prepare a
whole system of VSOP2. Then we must need close international collaboration to
get sufficient quality of resultant maps and to give a sufficient quantity of
observation time for astronomical community. We formed a new international
council to provide guidance on scientific aspects related of VSOP2, currently
called the VSOP2 International Science Council (VISC2).Comment: 10 pages, 9 figures, proceedings of The Universe under the Microscope
Astrophysics at High Angular Resolutio
Correlated Binomial Models and Correlation Structures
We discuss a general method to construct correlated binomial distributions by
imposing several consistent relations on the joint probability function. We
obtain self-consistency relations for the conditional correlations and
conditional probabilities. The beta-binomial distribution is derived by a
strong symmetric assumption on the conditional correlations. Our derivation
clarifies the 'correlation' structure of the beta-binomial distribution. It is
also possible to study the correlation structures of other probability
distributions of exchangeable (homogeneous) correlated Bernoulli random
variables. We study some distribution functions and discuss their behaviors in
terms of their correlation structures.Comment: 12 pages, 7 figure
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Associations between stratospheric variability and tropospheric blocking
There is widely believed to be a link between stratospheric flow variability and stationary, persistent “blocking” weather systems, but the precise nature of this link has proved elusive. Using data from the ERA-40 Reanalysis and an atmospheric general circulation model (GCM) with a well-resolved stratosphere (HadGAM), it is shown that there are in fact several different highly significant associations, with blocking in different regions being related to different patterns of stratospheric variability. This is true in both hemispheres and in both data sets. The associations in HadGAM are shown to be very similar to those in ERA-40, although the model has a tendency to underestimate both European blocking and the wave number 2 stratospheric variability to which this is related. Although the focus is on stratospheric variability in general, several of the blocking links are seen to occur in association with the major stratospheric sudden warmings. In general, the direction of influence appears to be upward, as blocking anomalies are shown to modify the planetary stationary waves, leading to an upward propagation of wave activity into the stratosphere. However, significant correlations are also apparent with the zonal mean flow in the stratosphere leading the occurrence of blocking at high latitudes. Finally, the underestimation of blocking is an enduring problem in GCMs, and an example has recently been given in which improving the resolution of the stratosphere improved the representation of blocking. Here, however, another example is given, in which increasing the stratospheric resolution unfortunately does not lead to an improvement in blocking
Vaccum solutions of five-dimensional Einstein equations generated by inverse scattering method II : Production of black ring solution
We study vacuum solutions of five-dimensional Einstein equations generated by
the inverse scattering method. We reproduce the black ring solution which was
found by Emparan and Reall by taking the Euclidean Levi-Civita metric plus
one-dimensional flat space as a seed. This transformation consists of two
successive processes; the first step is to perform the three-solitonic
transformation of the Euclidean Levi-Civita metric with one-dimensional flat
space as a seed. The resulting metric is the Euclidean C-metric with extra
one-dimensional flat space. The second is to perform the two-solitonic
transformation by taking it as a new seed. Our result may serve as a stepping
stone to find new exact solutions in higher dimensions.Comment: 12 pages, to be published in PR
A simple environment-dependent overlap potential and Cauchy violation in solid argon
We develop an analytic and environment-dependent interatomic potential for
the overlap repulsion in solid argon, based on an approximate treatment of the
non-orthogonal Tight-Binding theory for the closed-shell systems. The present
model can well reproduce the observed elastic properties of solid argon
including Cauchy violation at high pressures, yet very simple. A useful and
novel analysis is given to show how the elastic properties are related to the
environment-dependence incorporated into a generic pairwise potential. The
present study has a close link to the broad field of computational materials
science, in which the inclusion of environment dependence in short-ranged
repulsive part of a potential model is sometimes crucial in predicting the
elastic properties correctly.Comment: 10 pages, 3 figure
Electrodynamics of Media
Contains reports on four research projects.Joint Services Electronics Program (Contract DAAB07-74-C-0630)California Institute of Technology (Contract 953524
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