5,859 research outputs found
Recommended from our members
Temporary Programs to Extend Unemployment Compensation
[From Summary] The federal/state unemployment compensation (UC) system is designed to provide temporary and partial wage replacement to workers who have become involuntarily unemployed. UC also helps to stabilize the economy by providing unemployed workers with additional purchasing power, which serves as an economic stimulus when unemployment rises during recessions. The UC system generally provides sufficient duration of benefits during periods of economic prosperity, as most UC beneficiaries experience fewer weeks of unemployment than their maximum entitlements and return to work before their benefit rights are exhausted. However, during periods of economic decline, people tend to remain unemployed longer because of the greater difficulty in finding new jobs, and a rising proportion of jobless workers exhaust UC benefits without finding new work. Thus, programs have been established to increase the number of weeks of assistance during periods of high unemployment
Sudden future singularities in FLRW cosmologies
The standard energy conditions of classical general relativity are applied to
FLRW cosmologies containing sudden future singularities. Here we show, in a
model independent way, that although such cosmologies can satisfy the null,
weak and strong energy conditions, they always fail to satisfy the dominant
energy condition. They require a divergent spacelike energy flux in all but the
comoving frame.Comment: revtex4. Added references and a definition. To appear in CQ
Galactic Potentials
The information contained in galactic rotation curves is examined under a
minimal set of assumptions. If emission occurs from stable circular geodesic
orbits of a static spherically symmetric field, with information propagated to
us along null geodesics, observed rotation curves determine galactic potentials
without specific reference to any metric theory of gravity. Given the
potential, the gravitational mass can be obtained by way of an anisotropy
function of this field. The gravitational mass and anisotropy function can be
solved for simultaneously in a Newtonian limit without specifying any specific
source. This procedure, based on a minimal set of assumptions, puts very strong
constraints on any model of the "dark matter".Comment: A somewhat longer form of the final version to appear in Physical
Review Letters.Clarification and further reference
Enhancing the thermal performance of temporary fabric structures for the advanced energy efficient shelter system
The focus of this research is to characterize the thermal load on temporary fabric shelters deployed in the Middle East in order to establish realistic contract specification for the thermal performance of future shelters. Three different testing methods were utilized to evaluate shelter thermal performance. Small-scale tests allowed for economical comparisons of different shelter materials and configurations
Optomechanically induced transparency and cooling in thermally stable diamond microcavities
Diamond cavity optomechanical devices hold great promise for quantum
technology based on coherent coupling between photons, phonons and spins. These
devices benefit from the exceptional physical properties of diamond, including
its low mechanical dissipation and optical absorption. However the nanoscale
dimensions and mechanical isolation of these devices can make them susceptible
to thermo-optic instability when operating at the high intracavity field
strengths needed to realize coherent photon--phonon coupling. In this work, we
overcome these effects through engineering of the device geometry, enabling
operation with large photon numbers in a previously thermally unstable regime
of red-detuning. We demonstrate optomechanically induced transparency with
cooperativity > 1 and normal mode cooling from 300 K to 60 K, and predict that
these device will enable coherent optomechanical manipulation of diamond spin
systems
Detection of zeptojoule microwave pulses using electrothermal feedback in proximity-induced Josephson junctions
We experimentally investigate and utilize electrothermal feedback in a
microwave nanobolometer based on a normal-metal
(\mbox{Au}_{x}\mbox{Pd}_{1-x}) nanowire with proximity-induced
superconductivity. The feedback couples the temperature and the electrical
degrees of freedom in the nanowire, which both absorbs the incoming microwave
radiation, and transduces the temperature change into a radio-frequency
electrical signal. We tune the feedback in situ and access both positive and
negative feedback regimes with rich nonlinear dynamics. In particular, strong
positive feedback leads to the emergence of two metastable electron temperature
states in the millikelvin range. We use these states for efficient threshold
detection of coherent 8.4 GHz microwave pulses containing approximately 200
photons on average, corresponding to 1.1 \mbox{ zJ} \approx 7.0 \mbox{ meV}
of energy
- …