1,726 research outputs found

    Incidence of Auroras and Their North-South Motions in the Northern Auroral Zone

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    Studies of the incidence of auroral forms and their north and south motions are made by using a close-spaced array of all-sky cameras located in the northern auroral zone at the approximate geomagnetic longitude 250°E. It is found that during the observing season 1957-58 the peak of the average auroral zone occurred at 66-67° geomagnetic latitude. Although the southern extent of auroras retreats northward after local magnetic midnight, the southward motion of the individual forms, observed at the southern edge of the auroral zone, predominates over the northward motion throughout most of the night. The data indicate the existence on any given night of a latitude position near which many auroral forms occur. The first motion of auroras incident north of this position tends to be northward, and the first motion of auroras incident south of this position tends to be southward. A curve showing the occurrence of auroral forms peaks at, and is nearly symmetrical about, local geographic midnight, but the intensity of auroral emissions measured over the celestial hemisphere remains at a high level after midnight.NSP Grant No. Y/22.6/327Ye

    Accretion and evolution of solar system bodies

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    We use a combination of analytical and numerical methods to study dynamical processes involved in the formation of planets and smaller bodies in the solar system. Our goal was to identify and understand critical processes and to link them in a numerical model of planetesimal accretion. We study effects of these processes by applying them in the context of the standard model of solar system formation, which involves accretion of the terrestrial planets and cores of the giant planet from small planetesimals. The principal focus of our research effort is the numerical simulation of accretion of a swarm of planetesimals into bodies of planetary size. Our computer code uses a Monte Carlo method to determine collisional interactions within the swarm. These interactions are not determined simply by a relative velocity, but rather by explicit distributions of keplerian orbital elements. The planetesimal swarm is divided into a number of zones in semimajor axis, which are allowed to interact. The present version of our code has the capability of following detailed distributions of size, eccentricity, and inclination in each zone

    Understanding asteroid collisional history through experimental and numerical studies

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    Asteroids can lose angular momentum due to so called splash effect, the analog to the drain effect for cratering impacts. Numerical code with the splash effect incorporated was applied to study the simultaneous evolution of asteroid sized and spins. Results are presented on the spin changes of asteroids due to various physical effects that are incorporated in the described model. The goal was to understand the interplay between the evolution of sizes and spins over a wide and plausible range of model parameters. A single starting population was used both for size distribution and the spin distribution of asteroids and the changes in the spins were calculated over solar system history for different model parameters. It is shown that there is a strong coupling between the size and spin evolution, that the observed relative spindown of asteroids approximately 100 km diameter is likely to be the result of the angular momentum splash effect

    CONFLICT OF LAWS-SUIT BY FOREIGN ADMINISTRATOR UNDER WRONGFUL DEATH ACT OF HIS STATE

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    Plaintiff, an administrator appointed by a Michigan court, brought action in New York to recover for the wrongful death in Michigan of his infant daughter. Defendant moved to dismiss on the ground that a foreign administrator had no standing to sue in New York without first obtaining ancillary letters. Held, motion denied. A foreign administrator, suing as a statutory trustee, is entitled to maintain action in New York on the strength of his original letters. Wiener v. Specific Pharmaceuticals, Inc., 298 N.Y. 346, 83 N.E. (2d) 673 (1949)

    Sensory Aids Research

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    Contains reports on three research projects.National Institutes of Health (Grant MH-04737-02)National Science Foundation (Grant G-16526)United States Air Force, Electronic Systems Division (Contract AF19(628)-258

    Lunar and Martian hardware commonality

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    A number of different hardware elements were examined for possible Moon/Mars program commonality. These include manned landers; cargo landers, a trans-Mars injection (TMI) stage, traverse vehicles, unmanned surface rovers, habitation modules, and power supplies. Preliminary analysis indicates that it is possible to build a common two-stage manned lander. A single-stage, reusable lander may be practical for the lunar cast, but much less so for the Martian case, and commonality may therefore exist only at the subsystem level. A modified orbit transfer vehicle was examined as a potential cargo lander. Potential cargoes to various destinations were calculated for a Shuttle external tank sized TMI stage. A nuclear powered, long range traverse vehicle was conceptually designed and commonality is considered feasible. Short range, unmanned rovers can be made common without great effort. A surface habitation module may be difficult to make common due to difficulties in landing certain shapes on the Martian surface with aerobraking landers. Common nuclear power sources appear feasible. High temperature radiators appear easy to make common. Low temperature radiators may be difficult to make common. In most of these cases, Martian requirements determine the design

    Role of Leukotriene Receptor Antagonists in the Treatment of Exercise-Induced Bronchoconstriction: A Review

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    Asthma is a very common disorder that still causes significant morbidity and mortality. A high percentage of individuals with asthma also experience exercise-induced bronchoconstriction (EIB). This article reviews the current literature and updates the reader on the safety, efficacy, and clinical applications of leukotriene modifiers in the treatment of EIB

    Ranges and Movements of Montezuma Quail in Southeast Arizona

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    Historical assumptions about Montezuma quail movements and home ranges at the population level are limited due to the lack of markrecapture studies on this species from which solid conclusions can be derived. Such information is crucial for estimating population sizes, densities, and rate of emigration and immigration throughout the landscape. Our study examined home range size of 29 Montezuma quail and movements of 65 quail in southeast Arizona from 2008–2010. We used radio telemetry to follow radio-tagged birds in 3 study sites that varied in vegetation composition and topography. Mean home range size (MCP) was about was similar (51 ha) to the largest use area (50 ha) described in the literature for this species. The largest MCP home range estimate (206.7 ha) was far larger than what has been reported in the literature. Within a season, the largest mean maximum distance moved between 2 locations was 1,128.4 ± 619.5 m and the largest maximum linear distance between 2 locations for an individual was 2,375.5 m. Results from our research should help to address knowledge gaps about Montezuma quail home ranges and movements and provide a baseline to assist management of this species in the future

    Survival Demographics of Montezuma Quail in Southeast Arizona

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    Many facets of Montezuma quail (Cyrtonyx montezumae mearnsi) population dynamics, such as survival and causes of mortality, are unknown because of limited or lack of mark–recapture studies on wild populations of this species. Much of what is known about this species comes from casual observations in the field or from dog-assisted flush-count surveys. Further insight into rate and causes of mortality for this species is necessary to ensure proper conservation measures. We evaluated survival and causes of mortality of Montezuma quail in southeastern Arizona from winter 2007 to spring 2010. Survival was determined from quail captured, radiotagged, and monitored among 3 separate study sites. In 2 of these sites hunting was permitted; and in 1 site (the control) hunting was not permitted. Estimation of accurate mortality rates in hunted sites was complicated by large quantities of censored data, some of which was attributable to lack of reported mortalities from hunting. Mortality in the control site may have been compounded by a combination of stochastic events (i.e., wildfire, freezing) occurring during the study. Mortality rate for all sites were higher than any estimates reported or hypothesized in known scientific literature. The estimated rate of survival, combined among the 3 sites, was 21.9% from autumn 2008 to autumn 2009
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