Intraspecific Variation in Taxonomic Characteristics of the Mayfly \u3ci\u3ePotamanthus Myops\u3c/i\u3e (Walsh)

Data collected from an ecological study of the mayfly Potamanthus rnyops (Walsh) in Michigan showed intraspecific variability in taxonomic characteristics that have been employed by previous investigators for species separation. Nymphal dorsal maculation patterns varied considerably within a single population. Also, the ratio of mandibular tusk length to head length increased with successive nymphal instars. Certain adult taxonomic characteristics, particularly relative male imago eye size and distance of separation, were either too poorly defined or too variable to be conclusive in species identification

Gender Composition of Occupations and Earnings: Why Enter a Female Dominated Occupation?

Given the inverse relationship between the proportion of females employed in an occupation and earnings, why enter a female-dominated occupation? It has been argued that an individual’s total compensation from work is a combination of wage compensation plus non-pecuniary compensation associated with job characteristics, and when choosing an occupation, one selects the utility-maximizing combination of wages and job characteristics. Our findings support the theory that employee and job characteristics are rewarded differently in non-female dominated (NFD) and female dominated (FD) occupations, and that people choose occupations that reward their attributes more or penalize them less. Comparison of the variables significantly related to salary among FD occupations, NFD occupations and the full sample reveals that 9 of 13 variables significantly related to salary among NFD occupations are also significantly related to salary, with the same sign, among the full sample. However, none of these 13 variables is related to salary among FD occupations. This suggests that an individual’s labor force attributes are rewarded differently in FD occupations compared to NFD occupations and therefore any individual with a particular set of attributes can expect to be rewarded differently in a NFD occupation than in a FD occupation

Energy storage in the UK electrical network : estimation of the scale and review of technology options

This paper aims to clarify the difference between stores of energy in the form of non-rechargeable stores of energy such as fossil-fuels, and the storage of electricity by devices that are rechargeable. The existing scale of these two distinct types of storage is considered in the UK context, followed by a review of rechargeable technology options. The storage is found to be overwhelmingly contained within the fossil-fuel stores of conventional generators, but their scale is thought to be determined by the risks associated with long supply chains and price variability. The paper also aims to add to the debate regarding the need to have more flexible supply and demand available within the UK electrical network in order to balance the expected increase of wind derived generation. We conclude that the decarbonisation challenge facing the UK electricity sector should be seen not only as a supply and demand challenge but also as a storage challenge. (c) 2010 Elsevier Ltd. All rights reserved

The X-ray eclipse of OY Car resolved with XMM-Newton: X-ray emission from the polar regions of the white dwarf

We present the XMM-Newton X-ray eclipse lightcurve of the dwarf nova OY Car. The eclipse ingress and egress are well resolved for the first time in any dwarf nova placing strong constraints on the size and location of the X-ray emitting region. We find good fits to a simple linear eclipse model, giving ingress/egress durations of 30+/-3 sec. Remarkably this is shorter than the ingress/egress duration of the sharp eclipse in the optical as measured by Wood et al. (1989) and ascribed to the white dwarf (43+/-2 sec). We also find that the X-ray eclipse is narrower than the optical eclipse by 14+/-2 sec, which is precisely the difference required to align the second and third contact points of the X-ray and optical eclipses. We discuss these results and conclude that X-ray emission in OY Car most likely arises from the polar regions of the white dwarf. Our data were originally reported by Ramsay et al (2001), but they did not make a quantitative measurement of eclipse parameters. We have also corrected important timing anomalies present in the data available at that time.Comment: 6 pages, 5 figures; accepted for publication in MNRA

International price discovery in the presence of microstructure noise

This paper addresses and resolves the issue of microstructure noise when measuring the relative importance of home and U.S. market in the price discovery process of Canadian interlisted stocks. In order to avoid large bounds for information shares, previous studies applying the Cholesky decomposition within the Hasbrouck (1995) framework had to rely on high frequency data. However, due to the considerable amount of microstructure noise inherent in return data at very high frequencies, these estimators are distorted. We offer a modified approach that identifies unique information shares based on distributional assumptions and thereby enables us to control for microstructure noise. Our results indicate that the role of the U.S. market in the price discovery process of Canadian interlisted stocks has been underestimated so far. Moreover, we suggest that rather than stock specific factors, market characteristics determine information shares

Law Reform in Estonia: The Role of Georgetown University Law Center

On June 19, 1992, we and seven other members of the Georgetown University Law Center community landed in Tallinn, the capital of Estonia, to help the Estonian government draft laws to support a market economy. Our group consisted of six students, two professors, and an alumnus. The country to which we had come had declared its independence from the Soviet Union less than one year before. After fifty years of imposed communism, the Estonian leaders wanted to understand and adopt the basic foundations for a Western legal system that would support democratic and market institutions

The 1995 NRC Ratings of Doctoral Programs: A Hedonic Model

We describe how one can use multivariate regression models and data collected by the National Research Council as part of its recent ranking of doctoral programs (Research-Doctorate Programs in the United States: Continuity and Change) to analyze how measures of program size, faculty seniority, faculty research productivity, and faculty productivity in producing doctoral degrees influence subjective ratings of doctoral programs in 35 academic fields. Using data for one of the fields, economics, we illustrate how university administrators can use the models to compute the impact of changing the number of faculty positions they allocate to the field on the ranking of their programs. Finally, we illustrate how administrators can decompose the differences between a department\u27s rating and the ratings of a group of higher ranked departments in the field into difference due to faculty size, faculty seniority, faculty research productivity, and faculty productivity in producing doctoral students. This decomposition suggests the types of questions that a department and a university should be addressing if they are serious about wanting to improve the department\u27s ranking