7,018 research outputs found
Photon lifetime in a cavity containing a slow-light medium
We investigate experimentally the lifetime of the photons in a cavity
containing a medium exhibiting strong positive dispersion. This intracavity
positive dispersion is provided by a metastable helium gas at room temperature
in the electromagnetically induced transparency (EIT) regime, in which light
propagates at a group velocity of the order of 10000 m/s. The results
definitely prove that the lifetime of the cavity photons is governed by the
group velocity of light in the cavity, and not its phase velocity.Comment: Accepted for publication in Optics Letter
The Phase-Out and Sunset of Travel Restrictions in the International Health Regulations
Whether and to what extent travel restriction should be implemented during international infectious disease epidemics became a controversial issue, most recently, during the 2014 Ebola outbreak. The primary authority on the manner in which to respond to such epidemics is the International Health Regulations (IHR). The IHR is a treaty, established by the World Health Organization (WHO), which governs and coordinates international responses to international infectious disease epidemics. Despite the WHO\u27s strong advisement to the contrary, many countries who were signatories to the IHR implemented travel bans and other types of travel restrictions to prevent the transmission of the disease to their respective territories. Therefore, as evidenced by this outcome, the IHR has fallen short in regulating this use of travel restrictions by the international community. As a solution to this shortcoming, this Note proposes a framework of sunsetting phase-out provisions that will cause the IHR to more effectively and precisely regulate the use of travel restrictions by signatories to the IHR, while also preserving the aspects of the IHR that strongly aim to both protect and preserve elements of human rights, the international economy, international public health, and state sovereignty
Head and Neck Manifestations of Eosinophilic Granulomatosis with Polyangiitis: A Systematic Review.
OBJECTIVE: To conduct the first and only systematic review of the existing literature on head and neck manifestations of eosinophilic granulomatosis with polyangiitis to guide clinical decision making for the otolaryngologist.
DATA SOURCES: PubMed, Cochrane Library, Scopus, and LILACS.
REVIEW METHODS: A systematic review of the aforementioned sources was conducted per the PRISMA guidelines.
RESULTS: From an initial 574 studies, 28 trials and reports were included, accounting for a total of 1175 patients with eosinophilic granulomatosis with polyangiitis. Among clinical and cohort studies, 48.0% to 96.0% of all included patients presented with head and neck manifestations. In a distinct group of patients detailed in case reports describing patients presenting with head and neck manifestations, patients on average fulfilled 4.6 diagnostic criteria per the American College of Rheumatology. Furthermore, 95.8% of reported cases were responsive to steroids, and 60% required additional therapy.
CONCLUSION: Otolaryngologists are in a unique position for the early diagnosis and prevention of late complications of eosinophilic granulomatosis with polyangiitis. The American College of Rheumatology criteria should be relied on in the diagnostic workup. Close surveillance of these patients in a multidisciplinary fashion and with baseline complete blood counts, chest radiographs, and autoimmune laboratory tests is often necessary. Such patients with head and neck manifestations of the disease are nearly always responsive to steroids and often require additional immunosuppressive therapy or surgical intervention in cases of cranial neuropathies, temporal bone involvement, and refractory symptoms
Interacting double dark resonances in a hot atomic vapor of helium
We experimentally and theoretically study two different tripod configurations
using metastable helium (He*), with the probe field polarization
perpendicular and parallel to the quantization axis, defined by an applied weak
magnetic field. In the first case, the two dark resonances interact
incoherently and merge together into a single EIT peak with increasing coupling
power. In the second case, we observe destructive interference between the two
dark resonances inducing an extra absorption peak at the line center.Comment: 7 pages, 7 figure
Recommended from our members
Access to Care for VA Dialysis Patients During Superstorm Sandy.
Introduction: This study examines the use of dialysis services by end-stage renal disease (ESRD) patients following the Superstorm Sandy-related, months-long closure of the New York campus of the US Department of Veterans Affairs (VA) New York Harbor VA Healthcare System (NYHHS, Manhattan VAMC). Methods: Outpatient visits, dialysis care, emergency department visits, and hospitalizations at VA and non-VA facilities for 47 Manhattan VAMC ESRD patients were examined 12 months pre- and post-Sandy using VA administrative and clinical data. Results: The Brooklyn campus of NYHHS, which is within ten miles of Manhattan VAMC, experienced the largest increase in the number of dialysis encounters after the closure. Dialysis encounters for VA patients also increased at non-VA facilities, rising on average, to 106 per month. For the James J Peters Bronx VAMC, the number of total dialysis encounters for Manhattan VAMC patients fluctuated between 39 and 43 per month, dropping to less than 30 after the Manhattan VAMC dialysis unit reopened. Conclusion: Manhattan VAMC ESRD patients used nearby alternate VA sites and non-VA clinics for their care during the closure of the Manhattan VAMC dialysis unit. The VA electronic health records played an important role in ensuring continuity of care for patients who exclusively used VAMC facilities post-Sandy because patient information was immediately accessible at other VA facilities. The events related to Superstorm Sandy highlight the need for dialysis providers to have a comprehensive disaster plan, including nearby alternate care sites that can increase service capacity when a dialysis facility is closed because of a disaster
Interference in Bohmian Mechanics with Complex Action
In recent years, intensive effort has gone into developing numerical tools
for exact quantum mechanical calculations that are based on Bohmian mechanics.
As part of this effort we have recently developed as alternative formulation of
Bohmian mechanics in which the quantum action, S, is taken to be complex [JCP
{125}, 231103 (2006)]. In the alternative formulation there is a significant
reduction in the magnitude of the quantum force as compared with the
conventional Bohmian formulation, at the price of propagating complex
trajectories. In this paper we show that Bohmian mechanics with complex action
is able to overcome the main computational limitation of conventional Bohmian
methods -- the propagation of wavefunctions once nodes set in. In the vicinity
of nodes, the quantum force in conventional Bohmian formulations exhibits rapid
oscillations that pose severe difficulties for existing numerical schemes. We
show that within complex Bohmian mechanics, multiple complex initial conditions
can lead to the same real final position, allowing for the description of nodes
as a sum of the contribution from two or more crossing trajectories. The idea
is illustrated on the reflection amplitude from a one-dimensional Eckart
barrier. We believe that trajectory crossing, although in contradiction to the
conventional Bohmian trajectory interpretation, provides an important new tool
for dealing with the nodal problem in Bohmian methods
- âŠ