26,909 research outputs found
Conservativeness of non-symmetric diffusion processes generated by perturbed divergence forms
Let E be an unbounded open (or closed) domain in Euclidean space of dimension
greater or equal to two. We present conservativeness criteria for (possibly
reflected) diffusions with state space E that are associated to fairly general
perturbed divergence form operators. Our main tool is a recently extended
forward and backward martingale decomposition, which reduces to the well-known
Lyons-Zheng decomposition in the symmetric case.Comment: Corrected typos, minor modification
Proof-of-concept engineering workflow demonstrator
When Microsoft needed a proof-of-concept implementation of bespoke engineering workflow software for their customer,
BAE Systems, it called on the software engineering skills and
experience of the Microsoft Institute for High Performance
Computing.
BAE Systems was looking into converting their in-house SOLAR software suite to run on the MS Compute Cluster Server product with 64-bit MPI support in conjunction with an extended Windows Workflow environment for use by their engineer
On the correlation between metallicity and the presence of giant planets
The correlation between stellar metallicity and the presence of giant planets
is well established. It has been tentatively explained by the possible increase
of planet formation probability in stellar disks with enhanced amount of
metals. However, there are two caveats to this explanation. First, giant stars
with planets do not show a metallicity distribution skewed towards metal-rich
objects, as found for dwarfs. Second, the correlation with metallicity is not
valid at intermediate metallicities, for which it can be shown that giant
planets are preferentially found orbiting thick disk stars.
None of these two peculiarities is explained by the proposed scenarios of
giant planet formation. We contend that they are galactic in nature, and
probably not linked to the formation process of giant planets. It is suggested
that the same dynamical effect, namely the migration of stars in the galactic
disk, is at the origin of both features, with the important consequence that
most metal-rich stars hosting giant planets originate from the inner disk, a
property that has been largely neglected until now. We illustrate that a
planet-metallicity correlation similar to the observed one is easily obtained
if stars from the inner disk have a higher percentage of giant planets than
stars born at the solar radius, with no specific dependence on metallicity. We
propose that the density of molecular hydrogen in the inner galactic disk (the
molecular ring) could play a role in setting the high percentage of giant
planets that originate from this region.Comment: Accepted in ApJ
Estimation of Regional Evapotranspiration Using Remotely Sensed Land Surface Temperature. Part 1: Measurement of Evapotranspiration at the Environmental Research Center and Determination of Priestley-taylor Parameter
In order to study the distribution of evapotranspiration in the humid region using remote sensing technology, the parameter (alpha) in the Priestley-Taylor model was determined. The daily means of the parameter alpha = 1.14 can be available from summer to autumn and alpha = to approximately 2.0 in winter. The results of the satellite and the airborne sensing done on 21st and 22nd January, 1983, are described. Using the vegetation distribution in the Tsukuba Academic New Town, as well as the radiation temperature obtained by remote sensing and the radiation data observed at the ground surface, the evapotranspiration was calculated for each vegetation type by the Priestley-Taylor method. The daily mean evapotranspiration on 22nd January, 1983, was approximately 0.4 mm/day. The differences in evapotranspiration between the vegetation types were not detectable, because the magnitude of evapotranspiration is very little in winter
Estimation of Regional Evapotranspiration Using Remotely Sensed Land Surface Temperature. Part 2: Application of Equilibrium Evaporation Model to Estimate Evapotranspiration by Remote Sensing Technique
In a humid region like Japan, it seems that the radiation term in the energy balance equation plays a more important role for evapotranspiration then does the vapor pressure difference between the surface and lower atmospheric boundary layer. A Priestley-Taylor type equation (equilibrium evaporation model) is used to estimate evapotranspiration. Net radiation, soil heat flux, and surface temperature data are obtained. Only temperature data obtained by remotely sensed techniques are used
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