5,241 research outputs found
The Poisson Bracket for Poisson Forms in Multisymplectic Field Theory
We present a general definition of the Poisson bracket between differential
forms on the extended multiphase space appearing in the geometric formulation
of first order classical field theories and, more generally, on exact
multisymplectic manifolds. It is well defined for a certain class of
differential forms that we propose to call Poisson forms and turns the space of
Poisson forms into a Lie superalgebra.Comment: 40 pages LaTe
Investigation of Driver License Issuance Alternatives
This study develops an alternative model for issuing driver licenses and personal identifications in Kentucky. Under the current model, most licenses are distributed by circuit court clerks at 142 offices across the state while the Kentucky Transportation Cabinet (KYTC) provides central and regional support for specific license types. Given the cumbersome administrative structure and impending REAL ID requirements, both circuit clerks and KYTC administrators would like to explore an alternative distribution model. Researchers at the Kentucky Transportation Center (KTC) projected the costs of transitioning from the current issuance model to a centralized DMV model where licenses are distributed at 18 to 24 regional field offices. In FY 2020, the cost for having circuit clerks distribute licenses was roughly 10.4 and $16.4 million depending on the number of offices and employee compensation levels. If switching from a 4-year to 8-year license renewal cycle, the ensuing revenues would more than cover costs, although the License Fund allocation from each license sale should be adjusted so that all costs are covered and do not require additional Road Fund supplements. Optimizing the centralized issuance model will depend on transitioning from 4-year to 8-year license renewal intervals, completely transitioning issuance to KYTC and avoiding a hybrid distribution system and duplication of infrastructure, increasing allocations to the License Fund, implementing an online driver license renewal system in the near future, and transitioning away from the dated mainframe driver licensing database to a newer, more dynamic system
Radiation reaction on charged particles in three-dimensional motion in classical and quantum electrodynamics
We extend our previous work (see arXiv:quant-ph/0501026), which compared the
predictions of quantum electrodynamics concerning radiation reaction with those
of the Abraham-Lorentz-Dirac theory for a charged particle in linear motion.
Specifically, we calculate the predictions for the change in position of a
charged scalar particle, moving in three-dimensional space, due to the effect
of radiation reaction in the one-photon-emission process in quantum
electrodynamics. The scalar particle is assumed to be accelerated for a finite
period of time by a three-dimensional electromagnetic potential dependent only
on one of the spacetime coordinates. We perform this calculation in the
limit and show that the change in position agrees with that
obtained in classical electrodynamics with the Lorentz-Dirac force treated as a
perturbation. We also show for a time-dependent but space-independent
electromagnetic potential that the forward-scattering amplitude at order
does not contribute to the position change in the limit after the
mass renormalization is taken into account.Comment: Latex, 20page
Розробка нейромережевої інтелектуальної системи для прогнозування енергетичних центрів плямових зображень у процесах профілювання лазерного променя
Здійснено розробку нейромережевої інтелектуальної системи для прогнозування енергетичних центрів (ЕЦ) плямових зображень у процесах профілювання лазерного променя (ЛП). Обґрунтовано актуальність задачі прогнозування координат ЕЦ профілю ЛП. Розглянуто методи прогнозування та обґрунтовано доцільність застосування нейромережевої моделі. Здійснено комп’ютерне моделювання системи прогнозування, а також на основі отриманих результатів сформульовано вимоги та здійснено програмну реалізацію інтелектуальної системи.Выполнено разработку нейросетевой интеллектуальной системы для прогнозирования энергетических центров (ЭЦ) пятенных зображений в процесах профилирования лазерного луча (ЛЛ). Обоснована актуальность задачи прогнозирования координат ЭЦ профиля ЛЛ. Рассмотрены методы прогнозирования и обоснована целесообразность применения нейросетевой модели. Выполнено компьютерное моделирование системы прогнозирования, а также на основе полученных результатов сформулированы требования и выполнено программную реализацию интеллектуальной системы.The development of a neural net intellectual system for energy centers (EC) spot images forecasting in the processes of laser beam profiling (LB) is done. Actuality of the problem of coordinates forecasting of EC of laser beam profile is proved. Methods of forecasting are considered and the appropriateness of usage the neural net model is justified. Computer simulation of forecasting system is carried out and also on the basis of the obtained results the requirements are formulated and software implementation of intelligent system is performed
The potential role of T-cells and their interaction with antigen-presenting cells in mediating immunosuppression following trauma-hemorrhage
Objective: Trauma-hemorrhage results in depressed immune responses of antigen-presenting cells (APCs) and T-cells. Recent studies suggest a key role of depressed T-cell derived interferon (IFN)-g in this complex immune cell interaction. The aim of this study was to elucidate further the underlying mechanisms responsible for dysfunctional T-cells and their interaction with APCs following trauma-hemorrhage.
Design: Adult C3H/HeN male mice were subjected to trauma-hemorrhage (3-cm midline laparotomy) followed by hemorrhage (blood pressure of 35�5mmHg for 90 min and resuscitation) or sham operation. At 24 h thereafter, spleens were harvested and T-cells (by Microbeads) and APCs (via adherence) were Isolated. Co-cultures of T-cells and APCs were established for 48 h and stimulated with concanavalin A and lipopolysaccharide. T-Cell specific cytokines known to affect APC function (i.e. interleukin(IL)-2, IL-4 and granulocyte-macrophage colony-stimulating factor (GM-CSF)) were measured in culture supernatants by Multiplex assay. The expression of MHC class II as well as co-stimulatory surface molecules on T-cells and APCs was determined by flow cytometry.
Results: The release of IL-4 and GM-CSF by T-cells was suppressed following trauma-hemorrhage, irrespective of whether sham or trauma-hemorrhage APCs were present. Antigen-presenting cells from animals subjected to trauma-hemorrhage did not affect T-cell derived cytokine release by sham T-cells. In contrast, T-cells from traumahemorrhage animals depressed MHC class II expression of CD11c(þ) cells, irrespective of whether APCs underwent sham or trauma-hemorrhage procedure. Surprisingly, co-stimulatory molecules on APCs (CD80, CD86) were not affected by trauma-hemorrhage.
Conclusions: These results suggest that beside IFN-g other T-cell derived cytokines contribute to immunosuppression following trauma-hemorrhage causing diminished MHC II expression on APCs. Thus, T-cells appear to play an important role in this interaction at the time-point examined. Therapeutic approaches should aim at maintenance of T-cell function and their interaction with APCs to prevent extended immunosuppression following trauma-hemorrhage
Comparing Galaxy Morphology at Ultraviolet and Optical Wavelengths
We have undertaken an imaging survey of 34 nearby galaxies in far-ultraviolet
(FUV, ~1500A) and optical (UBVRI) passbands to characterize galaxy morphology
as a function of wavelength. This sample, which includes a range of classical
Hubble types from elliptical to irregular with emphasis on spirals at low
inclination angle, provides a valuable database for comparison with images of
high-z galaxies whose FUV light is redshifted into the optical and near-
infrared bands. Ultraviolet data are from the UIT Astro-2 mission. We present
images and surface brightness profiles for each galaxy, and we discuss the
wavelength-dependence of morphology for different Hubble types in the context
of understanding high-z objects. In general, the dominance of young stars in
the FUV produces the patchy appearance of a morphological type later than that
inferred from optical images. Prominent rings and circumnuclear star formation
regions are clearly evident in FUV images of spirals, while bulges, bars, and
old, red stellar disks are faint to invisible at these short wavelengths.
However, the magnitude of the change in apparent morphology ranges from
dramatic in early--type spirals with prominent optical bulges to slight in
late-type spirals and irregulars, in which young stars dominate both the UV and
optical emission. Starburst galaxies with centrally concentrated, symmetric
bursts display an apparent ``E/S0'' structure in the FUV, while starbursts
associated with rings or mergers produce a peculiar morphology. We briefly
discuss the inadequacy of the optically-defined Hubble sequence to describe FUV
galaxy images and estimate morphological k-corrections, and we suggest some
directions for future research with this dataset.Comment: Accepted for publication in the ApJS. 15 pages, 17 JPEG figures, 10
GIF figures. Paper and full resolution figures available at
http://nedwww.ipac.caltech.edu/level5/Kuchinski/frames.htm
Manipulation and removal of defects in spontaneous optical patterns
Defects play an important role in a number of fields dealing with ordered
structures. They are often described in terms of their topology, mutual
interaction and their statistical characteristics. We demonstrate theoretically
and experimentally the possibility of an active manipulation and removal of
defects. We focus on the spontaneous formation of two-dimensional spatial
structures in a nonlinear optical system, a liquid crystal light valve under
single optical feedback. With increasing distance from threshold, the
spontaneously formed hexagonal pattern becomes disordered and contains several
defects. A scheme based on Fourier filtering allows us to remove defects and to
restore spatial order. Starting without control, the controlled area is
progressively expanded, such that defects are swept out of the active area.Comment: 4 pages, 4 figure
The Kiloparsec-Scale Kinematics of High-Redshift Star-Forming Galaxies
We present the results of a spectroscopic survey of the kinematic structure
of star-forming galaxies at redshift z ~ 2 - 3 using Keck/OSIRIS integral field
spectroscopy. Our sample is comprised of 12 galaxies between redshifts z ~ 2.0
and 2.5 and one galaxy at z ~ 3.3 which are well detected in either HAlpha or
[O III] emission. These observations were obtained in conjunction with the Keck
laser guide star adaptive optics system, with a typical angular resolution
after spatial smoothing ~ 0.15" (approximately 1 kpc at the redshift of the
target sample). At most five of these 13 galaxies have spatially resolved
velocity gradients consistent with rotation while the remaining galaxies have
relatively featureless or irregular velocity fields. All of our galaxies show
local velocity dispersions ~ 60 - 100 km/s, suggesting that (particularly for
those galaxies with featureless velocity fields) rotation about a preferred
axis may not be the dominant mechanism of physical support. While some galaxies
show evidence for major mergers such evidence is unrelated to the kinematics of
individual components (one of our strongest merger candidates also exhibits
unambiguous rotational structure), refuting a simple bimodal disk/merger
classification scheme. We discuss these data in light of complementary surveys
and extant UV-IR spectroscopy and photometry, concluding that the dynamical
importance of cold gas may be the primary factor governing the observed
kinematics of z ~ 2 galaxies. We conclude by speculating on the importance of
mechanisms for accreting low angular-momentum gas and the early formation of
quasi-spheroidal systems in the young universe.(abridged)Comment: 34 pages, 13 figures. Revised version accepted for publication in the
Astrophysical Journal. Version with full-resolution figures is available at
http://www.astro.ucla.edu/~drlaw/Papers/OSIRIS_data2.pd
Effect of QRS duration and morphology on cardiac resynchronization therapy outcomes in mild heart failure: results from the Resynchronization Reverses Remodeling in Systolic Left Ventricular Dysfunction (REVERSE) study.
International audienceBACKGROUND: Cardiac resynchronization therapy (CRT) decreases mortality, improves functional status, and induces reverse left ventricular remodeling in selected populations with heart failure. We aimed to assess the impact of baseline QRS duration and morphology and the change in QRS duration with pacing on CRT outcomes in mild heart failure. METHODS AND RESULTS: Resynchronization Reverses Remodeling in Systolic Left Ventricular Dysfunction (REVERSE) was a multicenter randomized trial of CRT among 610 patients with mild heart failure. Baseline and CRT-paced QRS durations and baseline QRS morphology were evaluated by blinded core laboratories. The mean baseline QRS duration was 151±23 milliseconds, and 60.5% of subjects had left bundle-branch block (LBBB). Patients with LBBB experienced a 25.3-mL/m(2) mean reduction in left ventricular end-systolic volume index (P<0.0001), whereas non-LBBB patients had smaller decreases (6.7 mL/m(2); P=0.18). Baseline QRS duration was also a strong predictor of change in left ventricular end-systolic volume index with monotonic increases as QRS duration prolonged. Similarly, the clinical composite score improved with CRT for LBBB subjects (odds ratio, 0.530; P=0.0034) but not for non-LBBB subjects (odds ratio, 0.724; P=0.21). The association between clinical composite score and QRS duration was highly significant (odds ratio, 0.831 for each 10-millisecond increase in QRS duration; P<0.0001), with improved response at longer QRS durations. The change in QRS duration with CRT pacing was not an independent predictor of any outcomes after correction for baseline variables. CONCLUSION: REVERSE demonstrated that LBBB and QRS prolongation are markers of reverse remodeling and clinical benefit with CRT in mild heart failure. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT00271154
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