Applications of radio interferometry to navigation

Radio astronomy experiments have demonstrated the feasibility of making precise position measurements using interferometry techniques. The application of this method to navigation and marine geodesy is discussed, and comparisons are made with existing navigation systems. The very long baseline technique, with a master station, can use either an artificial satellite or natural sources as position references; a high-speed data link is required. A completely ship-borne system is shown to be feasible, at the cost of poorer sensitivity for natural sources. A comparison of Doppler, delay and phase-track modes of operating a very long baseline configuration is made, as that between instantaneous measurements and those where a source can be tracked from horizon to transit. Geometric limitations in latitude and longitude coverage are discussed. The characteristics of natural radio sources, their flux, distribution on the sky, and apparent size are shown to provide a limit on position measurements precision. The atmosphere and frequency standard used both contribute to position measurement uncertainty by affecting interferometric phase

Capabilities of GRO/OSSE for observing solar flares

The launch of the Gamma Ray Observatory (GRO) near solar maximum makes solar flare studies early in the mission particularly advantageous. The Oriented Scintillation Spectrometer Experiment (OSSE) on GRO, covering the energy range 0.05 to 150 MeV, has some significant advantages over the previous generation of satellite-borne gamma-ray detectors for solar observations. The OSSE detectors will have about 10 times the effective area of the Gamma-Ray Spectrometer (GRS) on Solar Maximum Mission (SMM) for both photons and high-energy neutrons. The OSSE also has the added capability of distinguishing between high-energy neutrons and photons directly. The OSSE spectral accumulation time (approx. 4s) is four times faster than that of the SMM/GRS; much better time resolution is available in selected energy ranges. These characteristics will allow the investigation of particle acceleration in flares based on the evolution of the continuum and nuclear line components of flare spectra, nuclear emission in small flares, the anisotropy of continuum emission in small flares, and the relative intensities of different nuclear lines. The OSSE observational program will be devoted primarily to non-solar sources. Therefore, solar observations require planning and special configurations. The instrumental and operational characteristics of OSSE are discussed in the context of undertaking solar observations. The opportunities for guest investigators to participate in solar flare studies with OSSE is also presented

The Effect of Dance and Team Sports on Mental Health

This study uses the World Health Organization model of physical, social, and mental health to examine the effect of participating in dance and team sports during childhood on mental health in adulthood. Prior research has suggested that physical activity is strongly integrated with mental and social health and therefore is a protective factor among mental illness. However, there is not sufficient research comparing the differences among dance and team sports on mental health. This study hypothesized that dancers would experience more positive mental health in adulthood than team sports due to the basis of physical activity in dance, but the distinguishing factors of dance that are not experienced in team sports such as emotional expression, creativity, and performance. This study was completed through an anonymous survey 16 item survey administered to women’s sports and dance teams in Massachusetts colleges. The results of this study indicate that dance and team sports display no statistically significant evidence of protecting against stress. Instead, this study suggests that stressors from college such as increased responsibility, independence, and physical separation from an individual\u27s support system may be increasing stress

The diversity of phytoplanktonic populations in oceanic, coastal, and estuarine regions

In the deep ocean north of Bermuda, during spring and summer, conditions for growth are poor, but physical conditions, such as high salinity and great depth, are favorable to the marine phytoplankton. The dominant species in a sample constitute a modest proportion of the cells counted, and a considerable diversity of species is observed...

Magnetic and Natural Rotatory Dispersion in Absorbing Media

A theoretical discussion based on the electron theory of H. A. Lorentz yielded formulas for the magnetic rotatory dispersion in isotropic absorbing media and for the natural rotatory dispersion in optically active absorbing media. In a few instances where sufficient data enabled calculation, the new magnetic rotation formula has given accurate agreement with experimental values, thereby accounting for the discrepancy previously noted between the observed Verdet angles and those calculated from a theory which neglected absorption

The application of set theory to ecology

Sets and membership are part of the structure of the world. Sets and membership hold nature together

Equity Carve-Outs And Changes In Corporate Control

This study proposes a corporate control hypothesis in which equity carve-outs facilitate changes in corporate control by providing an economical means to transfer control of corporate assets to bidders who will potentially create greater value.  Consistent with this hypothesis, a statistically significant 16% of the equity carve-outs in this study's sample are taken over within six years.  Those equity carve-outs subsequently taken over appear to be economically different from those motivated by other reasons.  Parent firms of equity carve-outs subsequently taken over display a significantly greater share price reaction to the announcement of an equity carve-out than do parent firms of equity carve-outs not subsequently taken over.  For those carve-outs subsequently taken over, an important factor contributing to parent firm gains is the relative size of the carve-out IPO.  There appears to be an optimal retention level of 10-50% for carve-outs motivated by the intent to facilitate a change in corporate control. &nbsp

Logical and set theory models for gastropod larvae, North American birds and seals of the world

Two logically valid models are used to compare the gastropod (snail) larvae of Atlantic and Pacific equatorial oceans with birds of North America. One model is this: if there is an environment that supports many species, then there are many species that are supported by one or more environments. This model says that the many species are supported by one environment in the ocean but are supported both by one environment and each species by its own environment among birds on land. A second model is this: if one environment is suited to many species then the many species are suited (adapted) to the one environment – this of course can be reversed, if species are suited to environment then environment is suited to species; so environment and species are suited to each other. This model is applicable to gastropod larvae of the ocean and the birds of North America. A set theory model is applied to the 32 species of seals (and sea lions) of the world. A set theory model is this: a bijective relation between each species and its environment or locale is such that there is a one-to-one correspondence between each species and its unique area or environment; whereas a surjective relation allows overlap of several species occupying the same area in a non one-to-one correspondence. There are 19 bijective seal species and 13 surjective seal species. Bijective cases are the North American birds interpreted as each being supported by and suited to its own area or environment. Surjective cases are many gastropod larvae supported by or suited to one ocean environment

Modelling ecology from logic

Submitted to Ecological ModellingThe thesis of this essay is that logically valid formulations guarantee correct and coherent summaries of scientific data. Several studies are presented that can be shown to be inadequate or simply wrong by logical procedures. But large and small aspects of nature are described and then summarized correctly by logically valid formulations