Raytheon

About: Raytheon is a company organization based out in Waltham, Massachusetts, United States. It is known for research contribution in the topics: Signal & Antenna (radio). The organization has 15290 authors who have published 18973 publications receiving 300052 citations.

System and method for adaptive path planning

Abstract: A path planning system and method for an object, such as a vehicle, provides a randomized adaptive path planning from starting position (RN) to a goal posotion (202) that handles real-time path planning for a vehicle operating under kinodynamic constraints in dynamically changing and uncertain environments with probabilistic knowledge of vehicle and obstacle (204a-f) movement

Increased salivary cortisol concentrations during chronic alcohol intoxication in a naturalistic clinical sample of men

Abstract: Background: Cortisol, the primary glucocorticoid in humans, is intimately involved in the regulation of such varied and critical biological processes as emotion, cognition, reward, immune functioning, and energy utilization. A persistent increase in cortisol concentration as a result of chronic intoxication could therefore result in alcohol-related disorders such as sleep disruption, cognitive deficits, diabetes, and mood disturbances. Although moderate levels of acute alcohol ingestion are reported to produce an increase in cortisol levels, it is uncertain whether cortisol remains persistently increased during long-term chronic intoxication. Methods: Salivary cortisol and breath alcohol concentrations (BAC) were obtained on 73 subjects with primary alcohol dependence on initial presentation for treatment and 22 alcohol-dependent subjects participating in a residential treatment program. Results: Both intoxicated alcohol-dependent subjects (n= 38) and nonintoxicated subjects in acute alcohol withdrawal (n= 30) demonstrated significantly increased salivary cortisol concentrations compared with abstinent subjects (n= 27; p 100 mg/dl) but were similar to subjects with lower levels of intoxication (BAC, 10–100 mg/dl). Conclusions: Chronic alcohol-dependent subjects experience continuously increased concentrations of cortisol during both intoxication and withdrawal. Increased levels of cortisol during chronic intoxication seem to progressively increase with the onset of withdrawal. This suggests a daily cycle of hypercortisolemia during the active drinking phase, with further increases on the cessation of drinking and the emergence of withdrawal symptoms. Persistently increased levels of cortisol may extract a costly allostatic load, resulting in significant central nervous system and peripheral organ morbidity.

Electron paramagnetic resonance of trivalent gadolinium ions in strontium and barium titanates

Abstract: This paper reports electron paramagnetic resonance data of substitutional ${\mathrm{Gd}}^{3+}$ impurities in the cubic and tetragonal phases of barium and strontium titanates. The pertinent spin Hamiltonian parameters are determined as a function of temperature in these two mentioned phases of both crystals. The temperature for the cubic-to-tetragonal phase transition in SrTi${\mathrm{O}}_{3}$ is determined from these data to be 110\ifmmode\pm\else\textpm\fi{}2.5\ifmmode^\circ\else\textdegree\fi{}K, a result that has been checked by the observation of the temperature dependence of the birefringence pattern of pure (undoped) crystals. This experiment is also briefly described. In the latter crystal we find a smooth transition, contrary to the corresponding case in BaTi${\mathrm{O}}_{3}$. The ${\mathrm{Gd}}^{3+}$ resonance results are compared with previous data on electron paramagnetic resonance of iron-group impurities, and some comments and conjectures are offered as to possible correlation of these results with the temperature dependence of certain properties of the host crystals in the neighborhood of the phase transition.

Correlations between Kilohertz Quasi-periodic Oscillations and Low-Frequency Features Attributed to Radial Oscillations and Diffusive Propagation in the Viscous Boundary Layer around a Neutron Star

Abstract: We present a dimensional analysis of two characteristic timescales in the boundary layer where the disk adjusts to the rotating neutron star (NS). The boundary layer is treated as a transition region between the NS surface and the first Keplerian orbit. The radial transport of the angular momentum in this layer is controlled by a viscous force defined by the Reynolds number, which in turn is related to the mass accretion rate. We show that the observed low-Lorentzian frequency is associated with radial oscillations in the boundary layer, where the observed break frequency is determined by the characteristic diffusion time of the inward motion of the matter in the accretion flow. Predictions of our model regarding relations between those two frequencies and the frequencies of kilohertz quasi-periodic oscillations (kHz QPOs) compare favorably with recent observations of the source 4U 1728-34. This Letter contains a theoretical classification of kHz QPOs in NS binaries and the related low-frequency features. Thus, results concerning the relationship between the low-Lorentzian frequency of viscous oscillations and the break frequency are presented in the framework of our model of kHz QPOs viewed as Keplerian oscillations in a rotating frame of reference.

Micro-electro-mechanical switch, and methods of making and using it.

Abstract: A micro-electro-mechanical (MEMS) switch (10, 110) has an electrode (22, 122) covered by a dielectric layer (23, 123), and has a flexible conductive membrane (31, 131) which moves between positions spaced from and engaging the dielectric layer. At least one of the membrane and dielectric layer has a textured surface (138) that engages the other thereof in the actuated position. The textured surface reduces the area of physical contact through which electric charge from the membrane can tunnel into and become trapped within the dielectric layer. This reduce the amount of trapped charge that could act to latch the membrane in its actuated position, which in turn effects a significant increase in the operational lifetime of the switch.