The observable effects of tidally induced warps in protostellar discs

We consider the response of a protostellar disc to a tidally induced warp and the resultant changes in the spectral energy distribution (SED). We argue that for typical protostellar disc parameters the warp is communicated through the disc in a wave-like fashion. We find that the main effects of the warp tend to be at large radii (greater than 30 AU) and, for sufficiently small viscosity, can be quite long-lived. This can result in non-uniform illumination of the disc at these radii and can induce significant changes to the SED at wavelengths greater than 100 microns.Comment: 7 pages, 9 figures. Accepted by MNRA

Ectoparasites of Isle Royale, Michigan

Isle Royale National Park is a rocky archipelago of approximately 200 islands and islets in northwestern Lake Superior. Politically it belongs to the State of Michigan situated 50 miles to the southeast. The main island lies parallel to the Canadian shore, which is from 12 to 15 miles to the northwest. It is 45 miles long, and 9 miles wide at its broadest point. A review of the climatological, vegetational, and geological features of the island is given by Mech (1966). Most of the material included in this paper was collected incidently by Johnson during a three-year study (1966-68) of the food habits of the red fox (Vulpes vulpes (Linnaeus)), and population dynamics of three of its principal prey species--the snowshoe rabbit (Lepus americanus), red squirrel (Tamiasciurus hudsonicus), and deer mouse (Peromyscus maniculatus) (see Johnson, 1969). The remaining material (196061) was collected by L. D. Mech during his studies of gray wolf (Canis lupus Linnaeus)-moose (Alces alces) relationships (see Mech, 1966)

An Annotated List of Phytophagous Insects Collected on Immature Black Walnut Trees in Southern Illinois

An annotated list of phytophagous insects on immature black walnut in southern Illinois was compiled between 26 April, 1974, and 9 October, 1975. Approximately 300 species, in 10 orders, were collected by hand-picking and sweeping. Notes taken on the various species included types of feeding damage, instars present, predators and parasites, and distribution in southern Illinois. Lepidoptera (about 80 species collected) were responsible for the majority of damage observed

A functional video-based anthropometric measuring system

A high-speed anthropometric three dimensional measurement system using the Selcom Selspot motion tracking instrument for visual data acquisition is discussed. A three-dimensional scanning system was created which collects video, audio, and performance data on a single standard video cassette recorder. Recording rates of 1 megabit per second for periods of up to two hours are possible with the system design. A high-speed off-the-shelf motion analysis system for collecting optical information as used. The video recording adapter (VRA) is interfaced to the Selspot data acquisition system

HOW MUCH DO FARMERS PAY IN TAXES?

A variety of federal, state, and local taxes are levied on farming operations in the United States. To date, there has been no attempt to systematically estimate what the total tax burden is on U.S. farms and how that burden varies from state to state. Based on the results of this analysis, the total farmer tax burden in 1994 was estimated at nearly $17 billion, most of which was in the form of real property tax (44%) and federal personal income tax (26%).farms, income taxes, property taxes, tax burdens, Agricultural Finance, Public Economics,

PRODUCER'S PREFERENCE FOR A COTTON FARMER OWNED RESERVE: AN APPLICATION OF SIMULATION AND STOCHASTIC DOMINANCE

The benefits to a typical High Plains cotton farmer from a cotton farmer owned reserve were estimated using a firm-level, income tax and farm policy simulation model. Eighteen farm programs were simulated including twelve variations of a farmer owned reserve using different entry prices and trigger prices. The after-tax net present value distributions for the different farm programs were compared using stochastic dominance. The results indicate that risk averse cotton producers should prefer the 1977 farm program to either a cotton farmer owned reserve or the farm program proposed by Secretary of Agriculture Block.Crop Production/Industries,

Rigidity of Frameworks Supported on Surfaces

A theorem of Laman gives a combinatorial characterisation of the graphs that admit a realisation as a minimally rigid generic bar-joint framework in \bR^2. A more general theory is developed for frameworks in \bR^3 whose vertices are constrained to move on a two-dimensional smooth submanifold \M. Furthermore, when \M is a union of concentric spheres, or a union of parallel planes or a union of concentric cylinders, necessary and sufficient combinatorial conditions are obtained for the minimal rigidity of generic frameworks.Comment: Final version, 28 pages, with new figure

The UK NHS Economic Evaluation Database : Economic issues in evaluations of health technology

Objective: The U.K. NHS Economic Evaluation Database (EED) project is commissioned to identify papers on economic evaluations of health technologies and to disseminate their findings to NHS decision makers by means of structured abstracts that are available through a public database and the Cochrane Library. This paper discusses current issues relating to the economic aspects of producing NHS EED abstracts. Methods: A review of NHS EED was undertaken between 1994 and 1999 to determine the methodologies adopted and issues that influence the usefulness of economic evaluations. Methods adopted to improve the quality of NHS EED abstracts are also reported. Results: Eighty-five percent of NHS EED abstracts are cost-effectiveness analyses (CEAs), 9.3% are cost-utility analyses (CUAs), and only 1.4% are cost-benefit analyses (CBAs). Of the total abstracts, 65.9% are based on single studies, 19.5% on reviews, 3.9% on estimates of effectiveness, and 10.7% on combinations of these sources. Models are utilized in 16.7% of CEAs, 60.2% of CUAs, and 20% of CBAs. Analyses of CBA studies reveal a degree of misuse of well-established definitions. NHS EED internal control mechanisms are reported that provide a means of ensuring that abstracts are based on sound academic principles. Conclusions: Most economic evaluations are conducted by means of CEA, followed by CUA, while CBA accounts for an extreme minority of cases. Single studies form the principal source of effectiveness data, although models are widely used, principally in CUA. The structure of NHS EED abstracts provides decision makers with the principal results and an interpretation of the relative strengths and weaknesses of economic evaluations

Retrograde Accretion and Merging Supermassive Black Holes

We investigate whether a circumbinary gas disc can coalesce a supermassive black hole binary system in the centre of a galaxy. This is known to be problematic for a prograde disc. We show that in contrast, interaction with a retrograde circumbinary disc is considerably more effective in shrinking the binary because there are no orbital resonances. The binary directly absorbs negative angular momentum from the circumbinary disc by capturing gas into a disc around the secondary black hole, or discs around both holes if the binary mass ratio is close to unity. In many cases the binary orbit becomes eccentric, shortening the pericentre distance as the eccentricity grows. In all cases the binary coalesces once it has absorbed the angular momentum of a gas mass comparable to that of the secondary black hole. Importantly, this conclusion is unaffected even if the gas inflow rate through the disc is formally super--Eddington for either hole. The coalescence timescale is therefore always $\sim M_2/\dot M$, where $M_2$ is the secondary black hole mass and $\dot M$ the inflow rate through the circumbinary disc.Comment: 8 pages, 4 figures. Accepted for publication in MNRAS. Movies of the simulations can be found at: http://www.astro.le.ac.uk/users/cjn12/RetroBinaryMovies.htm

Measuring the Economic Impact of High Speed Rail Construction for California and the Central Valley Region

The nation’s first high-speed rail project is under construction in California’s Central Valley as of the date of this report. This research analyzes the immediate economic impacts, focused on employment and spending generated by California High-Speed Rail (HSR) Construction Package 1 (CP1) in the Central Valley and the rest of California. The authors use a two-pronged approach that combines original economic analysis and modeling with case study vignettes that explore the economic impacts through the lens of a sample of businesses and individuals directly impacted by this phase of HSR development. Overall, the economic analysis suggests that CP1-related spending (forecasted through to 2019) will lead to more than 31,500 additional jobs (both part-time and full-time) by the year 2029. Growth is concentrated in Fresno County, with the number of additional jobs estimated at more than 15,500. The analysis considers job growth across a number of alternative scenarios, converting the raw jobs estimates to full-time equivalent job-years. Under the most conservative HSR spending scenario considered, over the 15-year period evaluated, more than 25,000 full-time equivalent job-years are created. This amount to 14,900 jobs per billion (real) dollars of spending, or a cost of approximately $67,200 per job-year