1,268 research outputs found
Thermodielectric radiometer
Radiometer measures microsecond pulses of radiant flux in the presence of electromagnetic noise. It consists of a charged capacitor that delivers a voltage pulse proportional to the thermally induced depolarization of its polymeric dielectric
Visual attitude orientation and alignment system
Active vehicle optical alignment aid and a passive vehicle three-dimensional alignment target ensure proper orientation and alignment plus control of the closure range and rate between two bodies, one in controlled motion and one at rest
Universal vortex-state Hall conductivity of YBa2Cu3O7 single crystals with differing correlated disorder
The vortex-state Hall conductivity ([sigma][sub]xy) of YBa2Cu3O7 single crystals in the anomalous-sign-reversal region is found to be independent of the density and orientation of the correlated disorder. After the anisotropic-to-isotropic scaling transformation is carried out, a universal scaled Hall conductivity [sigma][bar][sub]xy is obtained as a function of the reduced temperature (T/T[sub]c) and scaled magnetic field strength (H[bar]) for five samples with different densities and orientation of controlled defects. The transport scattering times {tau], derived from applying the model given by Feigel'man et al (Feigel'man M V, Geshkenbein V B, Larkin A I and Vinokur V M 1995 Pis. Zh. Eksp. Teor. Fiz. 62 811 (Engl. Transl. 1995 JETP Lett. 62 835)) to the universal Hall conductivity [sigma bar](T/T[sub]c, H[bar]), are consistent in magnitude with those derived from other measurements for quasiparticle scattering, and are much smaller than the thermal relaxation time of vortex displacement and than the vortex–defect interaction time. Our experimental results and analyses therefore suggest that the anomalous sign reversal in the vortex-state Hall conductivity is associated with the intrinsic properties of type-II superconductors, rather than extrinsic disorder effects
Laser beam hydrocarbon detector
Portable instrument passes light from helium-neon laser at a wavelength of 3.39 microns through the atmosphere being monitored and measures attenuation of the laser beam. Since beam attenuation is due almost exclusively to absorption of radiation by hydrocarbons, a quantitative measure of their concentration is available
Effects of lattice distortion and Jahn–Teller coupling on the magnetoresistance of La0.7Ca0.3MnO3 and La0.5Ca0.5CoO3 epitaxial films
Studies of La0.7Ca0.3MnO3 epitaxial films on substrates with a range of lattice constants reveal two dominant contributions to the occurrence of colossal negative magnetoresistance (CMR) in these manganites: at high temperatures (T → TC, TC being the Curie temperature), the magnetotransport properties are predominantly determined by the conduction of lattice polarons, while at low temperatures (T ≪ TC/, the residual negative magnetoresistance is correlated with the substrate-induced lattice distortion which incurs excess magnetic domain wall scattering. The importance of lattice polaron conduction associated with the presence of Jahn–Teller coupling in the manganites is further verified by comparing the manganites with epitaxial films of another ferromagnetic perovskite, La0.5Ca0.5CoO3. Regardless of the differences in the substrate-induced lattice distortion, the cobaltite films exhibit much smaller negative magnetoresistance, which may be attributed to the absence of Jahn–Teller coupling and the high electron mobility that prevents the formation of lattice polarons. We therefore suggest that lattice polaron conduction associated with the Jahn–Teller coupling is essential for the occurrence of CMR, and that lattice distortion further enhances the CMR effects in the manganites
Composite absorbing potentials
The multiple scattering interferences due to the addition of several
contiguous potential units are used to construct composite absorbing potentials
that absorb at an arbitrary set of incident momenta or for a broad momentum
interval.Comment: 9 pages, Revtex, 2 postscript figures. Accepted in Phys. Rev. Let
Independent evaluation of a simple clinical prediction rule to identify right ventricular dysfunction in patients with shortness of breath
BACKGROUND:
Many patients have unexplained persistent dyspnea after negative computed tomographic pulmonary angiography (CTPA). We hypothesized that many of these patients have isolated right ventricular (RV) dysfunction from treatable causes. We previously derived a clinical decision rule (CDR) for predicting RV dysfunction consisting of persistent dyspnea and normal CTPA, finding that 53% of CDR-positive patients had isolated RV dysfunction. Our goal is to validate this previously derived CDR by measuring the prevalence of RV dysfunction and outcomes in dyspneic emergency department patients.
METHODS:
A secondary analysis of a prospective observational multicenter study that enrolled patients presenting with suspected PE was performed. We included patients with persistent dyspnea, a nonsignificant CTPA, and formal echo performed. Right ventricular dysfunction was defined as RV hypokinesis and/or dilation with or without moderate to severe tricuspid regurgitation.
RESULTS:
A total of 7940 patients were enrolled. Two thousand six hundred sixteen patients were analyzed after excluding patients without persistent dyspnea and those with a significant finding on CTPA. One hundred ninety eight patients had echocardiography performed as standard care. Of those, 19% (95% confidence interval [CI], 14%-25%) and 33% (95% CI, 25%-42%) exhibited RV dysfunction and isolated RV dysfunction, respectively. Patients with isolated RV dysfunction or overload were more likely than those without RV dysfunction to have a return visit to the emergency department within 45 days for the same complaint (39% vs 18%; 95% CI of the difference, 4%-38%).
CONCLUSION:
This simple clinical prediction rule predicted a 33% prevalence of isolated RV dysfunction or overload. Patients with isolated RV dysfunction had higher recidivism rates and a trend toward worse outcomes
Civilians on the Battlefield: Creating a Realistic Training Aid for the United States Military
The United States and our allies and partners have adopted a humane approach to warfare based on established principle of the laws of war centered on the principles of Military Necessity, Humanity, Proportionality, Distinction, and Honor. These principles dictate that US Military forces conduct warfare with a careful consideration of our impact on civilian populations with a special duty to protect and limit harm as much as possible given the accomplishment of a mission. Likewise, the US Military has developed a sound counterinsurgency and unified action military model that recognizes that warfare is not fought simply with kinetic force, but rather is conducted across an array of areas, including the battle for “hearts and minds” of civilian populations to assist with military actions and legitimize lawful governments. These two factors contribute to a steady requirement to train military forces to respond properly when confronted with civilians on the battlefield. Unfortunately, the only viable method to provide this training is to employ large numbers of role-players – either in a live training setting or controlling entities in a wargame. These role-players must either be hired or be tasked from other military units. There are currently no viable autonomous solutions. The result is that commanders often choose to forego this training as too costly – which could have serious long-term ramifications for military forces confronting civilians in the real world.
Can agent based modelling accurately represent civilians confronted with military operations to provide realistic training for military leaders and Soldiers? This thesis investigates this question and develops an agent-based model to explore the answer
Book Review: The Soviet Union in World Affairs, A Documented Analysis, 1964-1972. By Professor W. W. Kulski. Syracuse: Syracuse University Press, 1972. Pp. 526. $17.50.
A Survey of Selected National Leaders in the Areas of Shorthand and Typewriting from 1956-1976
A thesis presented to the Business Education Graduate Committee at Morehead State University in partial fulfillment of the requirements for the Degree of Master of Business Education by Carolyn D. Beam on July 11, 1978
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