5,698 research outputs found
Proper definition and evolution of generalized transverse momentum distributions
We consider one of the most fundamental sets of hadronic matrix elements,
namely the generalized transverse momentum distributions (GTMDs), and argue
that their existing definitions lack proper evolution properties. By exploiting
the similarity of GTMDs with the much better understood transverse momentum
distributions, we argue that the existing definitions of GTMDs have to include
an additional dependence on soft gluon radiation in order to render them
properly defined. With this, we manage to obtain the evolution kernel of all
(un)polarized quark and gluon GTMDs, which turns out to be spin independent. As
a byproduct, all large logarithms can be resummed up to
next-to-next-to-leading-logarithmic accuracy with the currently known
perturbative ingredients.Comment: v2: typo in eq.(19) corrected. Matches published version in PLB. v1:
9 pages, 2 figure
Extrapolation of Galactic Dust Emission at 100 Microns to CMBR Frequencies Using FIRAS
We present predicted full-sky maps of submillimeter and microwave emission
from the diffuse interstellar dust in the Galaxy. These maps are extrapolated
from the 100 micron emission and 100/240 micron flux ratio maps that Schlegel,
Finkbeiner, & Davis (1998; SFD98) generated from IRAS and COBE/DIRBE data.
Results are presented for a number of physically plausible emissivity models.
We find that no power law emissivity function fits the FIRAS data from 200 -
2100 GHz. In this paper we provide a formalism for a multi-component model for
the dust emission. A two-component model with a mixture of silicate and
carbon-dominated grains (motivated by Pollack et al., 1994}) provides a fit to
an accuracy of about 15% to all the FIRAS data over the entire high-latitude
sky. Small systematic differences are found between the atomic and molecular
phases of the ISM.
Our predictions for the thermal (vibrational) emission from Galactic dust at
\nu < 3000 GHz are available for general use. These full-sky predictions can be
made at the DIRBE resolution of 40' or at the higher resolution of 6.1 arcmin
from the SFD98 DIRBE-corrected IRAS maps.Comment: 48 pages, AAS LaTeX, 6 figures, ApJ (accepted). Data described in the
text, as well as 4 additional figures, are available at
http://astro.berkeley.edu/dus
Non-Invasive Ventilation of the Neonate
The use of mechanical ventilation in the past few decades has greatly contributed to the survival of critically ill neonates, both preterm and term. With this, however, has come an accompanied rise in certain complications and neonatal co-morbidities. Avoiding mechanical ventilation, or at least minimizing the time a neonate is intubated, is considered a critical goal in the care of these patients. Different modes of non-invasive ventilation have developed over the course of the time to help address these issues
Evaluating the quality of selective emitter structures by imaging the emitter saturation current density
A method to derive the emitter saturation current density J0e with lateral resolution is applied to investigate selective emitter structures. The method uses PL lifetime imaging at several injection densities to laterally evaluate J0e by applying the method of Kane and Swanson [1] pixel by pixel. Samples with two-sided diffused emitters on lowlydoped Cz wafers were used to produce selective emitter structures by laser doping of the phosphorus-rich glass (LDSE). By comparison of experimental and numerical simulation results of J0e linescans, a limited resolution of a feature size of an inhomogeneous emitter is determined to be theoretically between 0.5-1.0 mm and experimentally about 2 mm. The method was successfully applied to investigate the dependence of J0e on the laser power of a selective emitter structure. The expected behaviour of a maximum J0e for medium laser intensities is observed. The method is suitable to evaluate the selective emitter process and its optimization.BMU/032520
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