8,144 research outputs found
Spurious Eccentricities of Distorted Binary Components
I discuss the effect of physical distortion on the velocities of close binary
components and how we may use the resulting distortion of velocity curves to
constrain some properties of binary systems, such as inclination and mass
ratio. Precise new velocities for 5 Cet convincingly detect these distortions
with their theoretically predicted phase dependence. We can even use such
distortions of velocity curves to test Lucy's theory of convective gravity
darkening. The observed distortions for TT Hya and 5 Cet require the contact
components of those systems to be gravity darkened, probably somewhat more than
predicted by Lucy's theory but clearly not as much as expected for a radiative
star. These results imply there is no credible evidence for eccentric orbits in
binaries with contact components. I also present some speculative analyses of
the observed properties of a binary encased in a non-rotating common envelope,
if such an object could actually exist, and discuss how the limb darkening of
some recently calculated model atmospheres for giant stars may bias my resuts
for velocity-curve distortions, as well as other results from a wide range of
analyses of binary stars.Comment: 14 pp, 2 tables, 12 fig; under review by Ap
Report of the Georgia Governorâs Wokersâ Compensation Review Commission
The Commission appointed by Governor Barnes consists of fourteen members, three ex officio members, and seven advisory members. This group includes academics, members of the legislature, claimants attorneys, defense attorneys, representatives from the insurance industry, organized labor, the textile industry, and government agencies. It was charged by the Governor to review and evaluate Georgiaâs laws and procedures affecting workersâ compensation. The Commissionâs primary goal was to prepare an accurate description of the current workersâ compensation system in Georgia. More specifically, this Report provides detailed information regarding the number of claims, benefits paid to employees, employer costs, and insurance profitability. It also compares workersâ compensation costs and benefits in Georgia with those in other states, particularly our Southeastern neighbors. Our purpose is to determine whether workersâ compensation costs place Georgia employers at a competitive disadvantage in regional and national markets. In preparing this Report, the Commission relied on the most recent available reports and data collected by organizations such as the National Academy of Social Insurance, the National Council on Compensation Insurance, the Workers Compensation Research Institute, the United States Department of Labor, and the Georgia State Board of Workersâ Compensation.Workers' Compemsation, wages, unemployment, disability, indemnity
Existence Advertising, Price Competition, and Asymmetric Market Structure
We examine a two stage duopoly game in which firms advertise their existence to consumers in stage 1 and compete in prices in stage 2. Whenever the advertising technology generates positive overlap in customer bases the equilib- rium for the stage 1 game is asymmetric in that one firm chooses to remain small in comparison to its competitor. For a specific random advertising technology we show that one firm will always be half as large as the other. No equilibrium in pure price strategies exists in the stage 2 game and as long as there is some overlap in customer bases the mixed strategy equilibrium is far from the Bertrand equilibrium.Existence advertising; price dispersion; Bertrand paradox; information; duopoly
Spam - solutions and their problems
We analyze the success of filtering as a solution to the spam problem when used alone or concurrently with sender and/or receiver pricing. We find that filters alone may exacerbate the spam problem if the spammer attempts to evade them by sending multiple variants of the message to each consumer. Sender and receiver prices can effectively reduce or eliminating spam, either on their own or when used together with filtering. Finally, we discuss the impli- cations for social welfare of using the different spam controls.Spam; filtering; email; receiver pricing; sender pricing
Punitive Damages and the Processing of Tort Claims
Punitive damages are one of the most controversial aspects of tort litigation and have been the subject of various theoretical, empirical, and experimental studies. One criticism of punitive damages refers to the effect that they have on civil litigation processes. In particular, Polinsky (1997) argues that the uncertainty and unpredictability that punitive damage claims inject into a case may increase both the rate and amount of settlements, thus implying that punitive damages carry systemic consequences for the general processing of tort claims. This paper represents the first, empirical examination of this implication. With one of the largest and most comprehensive data sets of tort litigation (over 25,000 cases filed from 1994 through 1997 in several counties in Georgia), we examine the effect of the decision to seek punitive damages on several major decision points in the tort litigation process in a series of logit regression models. With extensive control variables for type of case, the presence or absence of caps on damages, and other potentially important variables, we find that seeking punitive damages has no statistically significant effect on most phases of the tort litigation process.Torts, Litigation, Punitive Damages, Settlement Rates
Stereoisomerism in pentaerythritol-bridged cyclotriphosphazene tri-spiranes: spiro and ansa 1,3-propanediyldioxy disubstituted derivatives
Four isomeric products were isolated and purified from the reaction of 1,3-propanediol with the tetra-spirane cyclophosphazene-organophosphate compound (1): viz. the di-monospiro (2a), di-monoansa (2b) and two monospiro-monoansa derivatives (2c) and (2d). It is shown by 31P NMR spectroscopy on addition of a chiral solvating agent (CSA) that both the di-monospiro (2a) and di-monoansa (2b) derivatives are racemates, as expected, whereas no splitting of NMR signals occurred on addition of CSA to solutions of (2c) and (2d). It is found by X-ray crystallography that the two monospiro-monoansa spirane derivatives, (2c) and (2d), are meso diastereoisomers, which represent a new case of the stereochemistry of bis di-substituted cyclophosphazene derivatives of (1). It is also observed from the 31P NMR spectrum of the reaction mixture, supported by the yields of pure compounds, that formation of a spiro group is about 4.5 times more likely than that of an ansa moiety under the conditions of the reaction
Competitive formation of spiro and ansa derivatives in the reactions of tetrafluorobutane-1,4-diol with hexachlorocyclotriphosphazene: a comparison with butane-1,4-diol
Reaction of hexachlorocyclotriphosphazene, N3P3Cl6 (1), in two stoichiometries (1:1.2 and 1:3) with the sodium derivative of the fluorinated diol, 2,2,3,3-tetrafluorobutane-1,4-diol, (2), in THF solution at room temperature afforded six products, whose structures have been characterized by X-ray crystallography and 1H, 19F and 31P NMR spectroscopy: the mono-spiro compound, N3P3Cl4(OCH2CF2CF2CH2O), (3), its ansa isomer, (4), a di-spiro derivative N3P3Cl2(OCH2CF2CF2CH2O)2, (5), its spiro-ansa (6) and non-gem cis bis-ansa (7) isomers and a tri-spiro compound N3P3(OCH2CF2CF2CH2O)3, (8). The tri-spiro derivative (8) was also formed in the reaction of the ansa compound (4) with diol (2) in a 1:3 ratio in THF at room temperature. The reactions of (1) with step-wise additions of (2) were also investigated at low temperature (-780C) to give the same range of products as at room temperature. The results of all reactions are compared with previous work on the reactions of (1) with butane-1,4-diol/pyridine mixtures and with the reaction of hexafluorocyclotriphosphazene, N3P3F6 (9), with the silyl derivative of the diol (2), (Me3SiOCH2CF2)2, in a 1:0.4 mole ratio in the same solvent, THF
Spam: solutions and their problems
We analyze the success of filtering as a solution to the spam problem
when used alone or concurrently with sender and/or receiver pricing. We find
that filters alone may exacerbate the spam problem if the spammer attempts
to evade them by sending multiple variants of the message to each consumer.
Sender and receiver prices can effectively reduce or eliminating spam, either on
their own or when used together with filtering. Finally, we discuss the implications for social welfare of using the different spam controls
The Hudson Bay Lithospheric Experiment (HuBLE) : Insights into Precambrian Plate Tectonics and the Development of Mantle Keels
The UK component of HuBLE was supported by Natural Environment Research Council (NERC) grant NE/F007337/1, with financial and logistical support from the Geological Survey of Canada, CanadaâNunavut Geoscience Office, SEIS-UK (the seismic node of NERC), and First Nations communities of Nunavut. J. Beauchesne and J. Kendall provided invaluable assistance in the field. Discussions with M. St-Onge, T. Skulski, D. Corrigan and M. Sanborne-Barrie were helpful for interpretation of the data. D. Eaton and F. A. Darbyshire acknowledge the Natural Sciences and Engineering Research Council. Four stations on the Belcher Islands and northern Quebec were installed by the University of Western Ontario and funded through a grant to D. Eaton (UWO Academic Development Fund). I. Bastow is funded by the Leverhulme Trust. This is Natural Resources Canada Contribution 20130084 to its Geomapping for Energy and Minerals Program. This work has received funding from the European Research Council under the European Unions Seventh Framework Programme (FP7/2007-2013)/ERC Grant agreement no. 240473 âCoMITACâ.Peer reviewedPublisher PD
The nature of the faint galaxies in the Hubble Deep Field
We present a study of the galaxies found in the Hubble Deep Field. A high
proportion of HDF galaxies are undergoing a strong episode of star formation,
as evidenced by their very blue colours. A wide range of morphological types is
found, with a high proportion of peculiar and merger morphologies. Fitting the
multiband spectra with redshifted SEDs of galaxy types E to HII, we predict the
spectral types and redshifts of galaxies detected in the HDF. We find a median
redshift of 1.6, with having and with . The I-band
absolute magnitude distributions as a function of galaxy types show a plausible
trend of decreasing luminosity towards later types. The derived I-band
luminosity function agrees well with that from the Canada-France survey (Lilly
et al 1996) for and shows strong luminosity evolution at
for , comparable to the rate seen in quasars and starburst galaxies.
We have predicted infrared and submillimetre fluxes assuming most of the
galaxies are undergoing a strong starburst. Several planned space-borne and
ground-based deep surveys are capable of detecting interesting numbers of HDF
galaxies.Comment: 10 Pages, including diagram
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