1,661 research outputs found
Quantum radiation in a plane cavity with moving mirrors
We consider the electromagnetic vacuum field inside a perfect plane cavity
with moving mirrors, in the nonrelativistic approximation. We show that low
frequency photons are generated in pairs that satisfy simple properties
associated to the plane geometry. We calculate the photon generation rates for
each polarization as functions of the mechanical frequency by two independent
methods: on one hand from the analysis of the boundary conditions for moving
mirrors and with the aid of Green functions; and on the other hand by an
effective Hamiltonian approach. The angular and frequency spectra are discrete,
and emission rates for each allowed angular direction are obtained. We discuss
the dependence of the generation rates on the cavity length and show that the
effect is enhanced for short cavity lengths. We also compute the dissipative
force on the moving mirrors and show that it is related to the total radiated
energy as predicted by energy conservation.Comment: 17 pages, 1 figure, published in Physical Review
The morphological discrimination of microfilariae of Onchocerca volvulus from Mansonella ozzardi.
There is no published account which allows the morphological discrimination of microfilariae of Onchocerca volvulus and M. ozzardi from each other. However, they occur together in parts of Brazil and Venezuela, and presumably there is always the possibility that migration could establish new sympatric populations in the future. The objective of this study was to evaluate simple morphological characters that might be used for species-diagnosis of microfilariae. The conclusions were that the location of microfilariae in the blood or skin, the body size and the nucleation of the nerve ring are expected to be useful first indications of species identity, but cannot be used for confident diagnosis. The structure of the cephalic armature (stained with alcian blue) seems to be species specific, but is of limited application because it is often difficult to see. However, the pattern of nucleation of the tail (as expressed by the ratio of the length of the terminal nucleus compared with the length of the tail space) is distinctive and is expected to be diagnostic
Optical computing of quantum revivals
Interference is the mechanism through which waves can be structured into the
most fascinating patterns. While for sensing, imaging, trapping, or in
fundamental investigations, structured waves play nowadays an important role
and are becoming subject of many interesting studies. Using a coherent optical
field as a probe, we show how to structure light into distributions presenting
collapse and revival structures in its wavefront. These distributions are
obtained from the Fourier spectrum of an arrangement of aperiodic diffracting
structures. Interestingly, the resulting interference may present quasiperiodic
structures of diffraction peaks on a number of distance scales, even though the
diffracting structure is not periodic. We establish an analogy with revival
phenomena in the evolution of quantum mechanical systems and illustrate this
computation numerically and experimentally, obtaining excellent agreement with
the proposed theory.Comment: 10 pages, 4 figure
What is the topology of a Schwarzschild black hole?
We investigate the topology of Schwarzschild's black hole through the
immersion of this space-time in spaces of higher dimension. Through the
immersions of Kasner and Fronsdal we calculate the extension of the
Schwarzschild's black hole.Comment: 7 pages. arXiv admin note: substantial text overlap with
arXiv:1102.446
Envisioning health equity for American Indian/Alaska Natives: a unique HIT opportunity
The Indian Health Service provides care to remote and under-resourced communities in the United States. American Indian/Alaska Native patients have some of the highest morbidity and mortality among any ethnic group in the United States. Starting in the 1980s, the IHS implemented the Resource and Patient Management System health information technology (HIT) platform to improve efficiency and quality to address these disparities. The IHS is currently assessing the Resource and Patient Management System to ensure that changing health information needs are met. HIT assessments have traditionally focused on cost, reimbursement opportunities, infrastructure, required or desired functionality, and the ability to meet provider needs. Little information exists on frameworks that assess HIT legacy systems to determine solutions for an integrated rural healthcare system whose end goal is health equity. This search for a next-generation HIT solution for a historically underserved population presents a unique opportunity to envision and redefine HIT that supports health equity as its core mission
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