16,686 research outputs found
The Local Environments of Core-Collapse SNe within Host Galaxies
We present constraints on core-collapse supernova progenitors through
observations of their environments within host galaxies. This is achieved
through 2 routes. Firstly, we investigate the spatial correlation of supernovae
with host galaxy star formation using pixel statistics. We find that the main
supernova types form a sequence of increasing association to star formation.
The most logical interpretation is that this implies an increasing progenitor
mass sequence going from the supernova type Ia arising from the lowest mass,
through the type II, type Ib, and the supernova type Ic arising from the
highest mass progenitors. We find the surprising result that the supernova type
IIn show a lower association to star formation than type IIPs, implying lower
mass progenitors. Secondly, we use host HII region spectroscopy to investigate
differences in environment metallicity between different core-collapse types.
We find that supernovae of types Ibc arise in slightly higher metallicity
environments than type II events. However, this difference is not significant,
implying that progenitor metallicity does not play a dominant role in deciding
supernova type.Comment: to appear in Proceedings of IAU 279 "Death of Massive Stars:
Supernovae and Gamma-ray Bursts
A hybrid perturbation-Galerkin technique for partial differential equations
A two-step hybrid perturbation-Galerkin technique for improving the usefulness of perturbation solutions to partial differential equations which contain a parameter is presented and discussed. In the first step of the method, the leading terms in the asymptotic expansion(s) of the solution about one or more values of the perturbation parameter are obtained using standard perturbation methods. In the second step, the perturbation functions obtained in the first step are used as trial functions in a Bubnov-Galerkin approximation. This semi-analytical, semi-numerical hybrid technique appears to overcome some of the drawbacks of the perturbation and Galerkin methods when they are applied by themselves, while combining some of the good features of each. The technique is illustrated first by a simple example. It is then applied to the problem of determining the flow of a slightly compressible fluid past a circular cylinder and to the problem of determining the shape of a free surface due to a sink above the surface. Solutions obtained by the hybrid method are compared with other approximate solutions, and its possible application to certain problems associated with domain decomposition is discussed
Cyber-pseudepigraphy: A New Challenge for Higher Education Policy and Management
There is no lack of critical literature dealing with cyber-plagiarism and the implications for assessment in higher education. The practice of the selling of academic papers through the Internet is generally included under the category of plagiarism, although it is suggested that this ought to be considered under the separate category of cyber-pseudepigraphy. Pseudepigraphy is defined in this essay as the deliberate ascription of false authorship to a piece of writing, and cyber-pseudepigraphy is defined as using the Internet to have another person write an academic essay or paper, without this authorship being acknowledged. It is suggested that cyber-pseudepigraphy has widespread implications, and five critical issues are discussed. The essay finally raises the prospect of a return to some form of unseen examination as a method of student assessment as a way of dealing with this problem
The Missing Theory of Variable Selection in the Economic Analysis of Tort Law
The Article argues that the economic analysis of tort law has yet to satisfactorily answer a critical threshold question: which of the many inputs that lead to an accident should be included in a court’s liability analysis? As a result of this missing theory, the economic analysis of tort law provides indeterminate prescriptions. The Article shows how three separate areas of the literature can be seen as being about the general problem of which variables to include in the liability test and the tension between short- and long-run optima. The Article proposes an analytical framework—a continuum from short to long run—to understand the problem and show the way in which courts have crafted tort law doctrines to address the issue. Finally, the Article concludes that no satisfactory general theory is possible and that the optimal combination of liability rules will depend upon empirical questions about specific accident contexts
Solid-state conformation of copolymers of ß-benzyl-L-aspartate with L-alanine, L-leucine, L-valine, γ-benzyl-L-glutamate, or ε-carbobenzoxy-L-lysine
The solid-state conformation of copolymers of ß-benzyl-L-aspartate [L-Asp(OBzl)] with L-leucine (L-Leu), L-alanine (L-Ala), L-valine (L-Val), γ-benzyl-L-glutamate [L-Glu(OBzl)], or ε-carbobenzoxy-L-lysine (Cbz-L-Lys) has been studied by ir spectroscopy and circular dichroism (CD). The ir spectra in the region of the amide I and II bands and in the region of 700-250 cm-1 have been determined. The results from the ir studies are in good agreement with data obtained by CD experiments. Incorporation of the amino acid residues mentioned above into poly[L-Asp(OBzl)] induces a change from the left-handed into the right-handed α-helix. This conformational change for the poly[L-Asp(OBzl)] copolymers was observed in the following composition ranges: L-Leu, 0-15 mol %; L-Ala, 0-32 mol %; L-Val, 0-8 mol %; L-Glu(OBzl), 3-10 mol %; and Cbz-L-Lys, 0-9 mol %
Rights and Obligations in the Mutual Fund: A Source of Law
The proposals of this note, the thrust of statutory regulation, the trend of the case law and the direction of recent developments are all consistent. In a practical sense, the suggestions here attempt to provide a reasonable source of law for the men of the industry and for the courts in search of an authoritative system of behavioral standards. If, for example, a mutual fund has enjoyed such vigorous growth that the percentage fee now charged by the advisers has lost its relevance to the actual cost of management, the disgruntled shareholder or the apprehensive director would seek information on potential law suits. They would first turn, no doubt, to the Investment Company Act to determine whether the statute specifically imposed any duties that might be violated. Finding none, the interested party would, under the proposals of this paper, then turn to duties created by implication under the Investment Company Act or duties created by trust law. Having determined that such duties arguably exist, the party, to establish the scope of these duties, would then look to trust standards in the absence of controlling case law under the statute. Utilizing the principles of trust law under the theories set forth in this note, the shareholder might then build his brief, or the director govern his actions, on the basis of such law to the extent that it provides reasonable solutions. Suit could then be brought in conformity with the procedural requirements of standard corporation law. This technique, derived from rational analysis of the participants,emphasizes the best aspects of both predictability and fairness, and as such is worthy and capable of bracing the newly developing mutual fund law until such time as it has the strength to stand on its own. Once this point is reached, there will no longer be a need to borrow halfway relevant law from other sources or to run the risk of misdirection implicit in the utilization of law in an area for which it was not promulgated. But, until that time, it is senseless not to apply all the relevant learning possible to problems analogous to those about which substantial law already has been developed. It has been the purpose of this note to demonstrate the utility of this device for the mutual fund
Four methods of developing bulls to approximately 20 months of age
In the southeastern region of the United States there is an abundance of rainfall with warm temperatures for much of the year. These climatic conditions are favorable for the production of large amounts of forages and grains. However, much of the soil in the South east cannot compete with that of other areas of the country in the production of grain. The most logical method of producing meat products in this area would appear to be to make maximum use of roughages, provided these roughages could be utilized efficiently.
Making maximum use of large quantities of roughages is right down the alley for beef cattle because they have the ability, with the aid of rumen microorganisms, to convert these roughages into a usable product. Most post-weaning performance tests of beef cattle have embraced the idea that the best way to test the gain and feed utilization ability of an animal and his ability to pass these qualities on to his offspring is to feed the maximum amount of grain for 140 days, or some similar feeding period, and use his performance during this time as one of the criteria for selection of breeding stock. The justification for feeding a high-concentrate ration is based on the hypothesis that the performance of individual animals will be spread further apart on a high energy ration than on a low energy ration, and in so doing more information will be obtained on the potential production ability of the animals. There is no doubt that the 140-day test has been very instrumental in improving the production ability of beef cattle. However, in addition to being able to do a good job of converting concentrates to beef, cattle need to be bred that can ingest large quantities of low-cost roughages and convert these economically into usable products. Beef cattle, when fed primarily grain rations, are in direct competition with other species which have markedly lower feed conversion ratios. Therefore, the ideal performance testing scheme for beef cattle should identify differences in the ability of individual animals to produce high rates of gain on high-roughage, low-cost rations that the competing species cannot utilize as efficiently. Steers need to possess the ability to gain in the feedlot on high-concentrate rations. Yet, if maximum use is made of roughages, the feedlot period needed to produce steers with the amount of finish that most consumers prefer may only be a very small part of the steer\u27s total life span.
Both high-concentrate rations and high-roughage rations have some advantages as the ration to use in measuring post-weaning performance of prospective breeding bulls. Could a combination of these be used, effectively, to performance test beef cattle and to take advantage of the environmental assets of the Southeast? In absence of experimental data of this nature, a Record of Performance Test was designed by members of the Animal Husbandry-Veterinary Science Department at the University of Tennessee with the following objectives in mind:
1. To test the performance of the progeny of various sires.
2. To determine the level of feeding that would do the best job of developing and evaluating bulls to breeding age of approximately 20 months.
This thesis will be concerned with objective two only
TRIG-STAR
A TRIG-STAR is a mathematics student who has demonstrated in competition that he or she is the most skilled among classmates in the practical application of trigonometry. The competition for the honor is a timed exercise which is the solving of a trigonometry problem that incorporates the use of right triangle formulas, circle formulas, the law of sines, and the law of cosines. The contest helps to promote careers in surveying and mapping to students at the High Schools across the country. The award is sponsored by the National Society of Professional Surveyors and cosponsored locally. State winners also have the opportunity to participate in the National TRIG-STAR competition for awards. Visit the Trig-Star website at www.trig-star.info
Perception & Use of Magnetic Field Information in Navigation Behaviors in Elasmobranch Fishes.
Ph.D. Thesis. University of Hawaiʻi at Mānoa 2018
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