545 research outputs found
Casimir-Polder intermolecular forces in minimal length theories
Generalized uncertainty relations are known to provide a minimal length
. The effect of such minimal length in the Casimir-Polder
interactions between neutral atoms (molecules) is studied. The first order
correction term in the minimal uncertainty parameter is derived and found to
describe an attractive potential scaling as as opposed to the well
known long range retarded potential.Comment: 1 Figure. Version published by Physical Review D. Few references
added, typos correcte
The Southern Flying Squirrel (\u3ci\u3eGlaucomys volans\u3c/i\u3e) in Lincoln, Nebraska
The southern flying squirrel (Glaucomys volans) is considered a species of greatest conservation need in Nebraska and listed as threatened in the state. Historically, the geographic range of the southern flying squirrel in Nebraska has been restricted to five eastern counties from a northern suburb of Omaha, Douglas Co., southward in the four counties of Sarpy, Otoe, Nemaha, and Richardson, all bordering the Missouri River on the east. In late November of 2018, a resident of Lincoln, Lancaster Co., Nebraska, contacted the Nebraska Game and Parks Commission about an animal found dead in his yard. This animal proved to be a southern flying squirrel, which was 50 [80 km] to 70 [112 km] miles west of the known geographic range of the species. Two additional individuals were subsequently observed at the original residence as were individuals in at least eight separate neighborhoods throughout the city of Lincoln. Clearly, a population of the southern flying squirrels is established and reproducing in Lincoln, but their origin is unknown. The source of this city-dwelling population may be from released/escaped pets, a natural dispersal from the Missouri River via the Platte River and Salt Creek, or inadvertent translocation when moving timber or fire wood
Scattering of Woods-Saxon Potential in Schrodinger Equation
The scattering solutions of the one-dimensional Schrodinger equation for the
Woods-Saxon potential are obtained within the position-dependent mass
formalism. The wave functions, transmission and reflection coefficients are
calculated in terms of Heun's function. These results are also studied for the
constant mass case in detail.Comment: 14 page
Sneutrino-induced like sign dilepton signal with conserved R-parity
Lepton number violation could be manifest in the sneutrino sector of
supersymmetric extensions of the standard model with conserved R-parity. Then
sneutrinos decay partly into the ``wrong sign charged lepton'' final state, if
kinematically accessible. In sneutrino pair production or associated single
sneutrino production, the signal then is a like sign dilepton final state.
Under favourable circumstances, such a signal could be visible at the LHC or a
next generation linear collider for a relative sneutrino mass-splitting of
order and sneutrino width of order (1 GeV). On the
other hand, the like sign dilepton event rate at the TEVATRON is probably too
small to be observable.Comment: 19 pages, 14 Figures. Section about LSD at LHC and TEVATRON added.
Previous Title "Single sneutrino production and the wrong charged lepton
signal
Thermal conductivity measurements of proton-heated warm dense aluminum.
Thermal conductivity is one of the most crucial physical properties of matter when it comes to understanding heat transport, hydrodynamic evolution, and energy balance in systems ranging from astrophysical objects to fusion plasmas. In the warm dense matter regime, experimental data are very scarce so that many theoretical models remain untested. Here we present the first thermal conductivity measurements of aluminum at 0.5-2.7 g/cc and 2-10 eV, using a recently developed platform of differential heating. A temperature gradient is induced in a Au/Al dual-layer target by proton heating, and subsequent heat flow from the hotter Au to the Al rear surface is detected by two simultaneous time-resolved diagnostics. A systematic data set allows for constraining both thermal conductivity and equation-of-state models. Simulations using Purgatorio model or Sesame S27314 for Al thermal conductivity and LEOS for Au/Al release equation-of-state show good agreement with data after 15 ps. Discrepancy still exists at early time 0-15 ps, likely due to non-equilibrium conditions
Mixing in the Presence of Isosinglet Quarks
We analyse transitions in the framework of a minimal extension
of the Standard Model where either a or a isosinglet quark is
added to the standard quark spectrum. In the case of a isosinglet
quark, it is shown that there is a significant region of parameter space where
mixing is sufficiently enhanced to be observed at the next
round of experiments. On the contrary, in the case of a isosinglet
quark, it is pointed out that obtaining a substancial enhancement of mixing, while complying with the experimental constraints on rare
kaon decays, requires a contrived choice of parameters.Comment: 10 pages plus four figures. The figures are not included but are
available upon reques
The Casimir Effect in Minimal Length Theories based on a Generalized Uncertainity Principle
We study the corrections to the Casimir effect in the classical geometry of
two parallel metallic plates, separated by a distance , due to the presence
of a minimal length () arising from quantum mechanical
models based on a Generalized Uncertainty Principle (GUP). The approach for the
quantization of the electromagnetic field is based on projecting onto the
maximally localized states of a few specific GUP models and was previously
developed to study the Casimir-Polder effect. For each model we compute the
lowest order correction in the minimal length to the Casimir energy and find
that it scales with the fifth power of the distance between the plates
as opposed to the well known QED result which scales as and, contrary
to previous claims, we find that it is always attractive. The various GUP
models can be in principle differentiated by the strength of the correction to
the Casimir energy as every model is characterized by a specific multiplicative
numerical constant.Comment: 19 pages, 1 figur
The impact of care pathways for exacerbation of Chronic Obstructive Pulmonary Disease: rationale and design of a cluster randomized controlled trial
<p>Abstract</p> <p>Background</p> <p>Hospital treatment of chronic obstructive pulmonary disease (COPD) frequently does not follow published evidences. This lack of adherence can contribute to the high morbidity, mortality and readmissions rates. The European Quality of Care Pathway (EQCP) study on acute exacerbations of COPD (NTC00962468) is undertaken to determine how care pathways (CP) as complex intervention for hospital treatment of COPD affects care variability, adherence to evidence based key interventions and clinical outcomes.</p> <p>Methods</p> <p>An international cluster Randomized Controlled Trial (cRCT) will be performed in Belgium, Italy, Ireland and Portugal. Based on the power analysis, a sample of 40 hospital teams and 398 patients will be included in the study. In the control arm of the study, usual care will be provided. The experimental teams will implement a CP as complex intervention which will include three active components: a formative evaluation of the quality and organization of care, a set of evidence based key interventions, and support on the development and implementation of the CP. The main outcome will be six-month readmission rate. As a secondary endpoint a set of clinical outcome and performance indicators (including care process evaluation and team functioning indicators) will be measured in both groups.</p> <p>Discussion</p> <p>The EQCP study is the first international cRCT on care pathways. The design of the EQCP project is both a research study and a quality improvement project and will include a realistic evaluation framework including process analysis to further understand why and when CP can really work.</p> <p>Trial Registration number</p> <p><b>NCT00962468</b></p
Adsorption Isotherms of Hydrogen: The Role of Thermal Fluctuations
It is shown that experimentally obtained isotherms of adsorption on solid
substrates may be completely reconciled with Lifshitz theory when thermal
fluctuations are taken into account. This is achieved within the framework of a
solid-on-solid model which is solved numerically. Analysis of the fluctuation
contributions observed for hydrogen adsorption onto gold substrates allows to
determine the surface tension of the free hydrogen film as a function of film
thickness. It is found to decrease sharply for film thicknesses below seven
atomic layers.Comment: RevTeX manuscript (3 pages output), 3 figure
Quantum Gravitational Corrections to the Real Klein-Gordon Field in the Presence of a Minimal Length
The (D+1)-dimensional -two-parameter Lorentz-covariant
deformed algebra introduced by Quesne and Tkachuk [C. Quesne and V. M. Tkachuk,
J. Phys. A: Math. Gen. \textbf {39}, 10909 (2006).], leads to a nonzero minimal
uncertainty in position (minimal length). The Klein-Gordon equation in a
(3+1)-dimensional space-time described by Quesne-Tkachuk Lorentz-covariant
deformed algebra is studied in the case where up to first order
over deformation parameter . It is shown that the modified Klein-Gordon
equation which contains fourth-order derivative of the wave function describes
two massive particles with different masses. We have shown that physically
acceptable mass states can only exist for which
leads to an isotropic minimal length in the interval . Finally, we have shown that the above estimation of
minimal length is in good agreement with the results obtained in previous
investigations.Comment: 10 pages, no figur
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