5,339 research outputs found

    Empirical Evidence for Collusion in the U.S. Auto Market?

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    A supergame theoretic price-setting model of collusion is calibrated to data from the North American passenger car market before, during, and after the voluntary restraint arrangements (VRAs) with Japan. Conclusions about whether the model is consistent with the bans from the various regimes depend on assumptions about market structure, demand elasticities, and discount factors. If one believes that the price elasticity of auto demand is about one, for example, then the calibrations suggest that in, the pre-VRA and VRA regimes, only General Motors and Ford could conceivably have colluded, and even this limited potential broke down in the post-VRA regime.

    The mass of the black hole in LMC X-3

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    New high resolution, optical spectroscopy of the high mass X-ray binary LMC X-3, shows the spectral type of the donor star changes with phase due to irradition by the X-ray source. We find the spectral type is likely to be B5V, and only appears as B3V when viewing the heated side of the donor. Combining our measurements with those previously published, and taking into account the effects of X-ray irradiation, results in a value for the donor star radial velocity semi-amplitude of Ko=256.7±4.9K_{o} = 256.7 \pm 4.9~km~s−1^{-1}. We find the mass of the black hole lies in the range 9.5M⊙≤Mx≤13.6M⊙9.5M_{\odot} \leq M_{\rm x} \leq 13.6M_{\odot}

    Being a researcher with intellectual disabilities:The hallmarks of inclusive research in action

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    The current chapter stems principally from work done at Norah Fry Research Centre at the University of Bristol in the UK, where inclusive research has been one of the hallmarks, and where from the outset, it has been acknowledged that there are many different models and approaches … However, all of these approaches aim … to introduce the voices of people with intellectual disabilities, as active agents in shaping their own lives and their own knowledge. This chapter therefore aims to showcase some of those voices, and to show how we can learn more about what constitutes inclusive research by analysing the fine detail of the interactions that take place during the conduct of research studies. … [The author] will focus here on a couple of points only. First … [he has] come to the conclusion that this link between the personal and political is one of the hallmarks of inclusive research ... Much depends therefore on the relationship between the disabled person and those around them, and how that plays itself out in everyday interactions. That point is also directly relevant for inclusive research contexts, and is one that [he hopes] to illustrate through data taken from two projects. The first study was carried out by and with a small group of people with ID in 1998 .... The second project … was a fully funded, national research study carried out in partnership with a self-advocacy organisation, looking at the interactions between support workers (personal assistants) and people with ID. … For the purposes of the current chapter, [the author focuses] on the study as an example of inclusive research, showing how it contrasted and added to the interactional knowledge from the earlier study in 1998. (DIPF/Orig.

    Vinton Street: Evolution of an ethnic retail ribbon, 1889-1989

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    Geographers and others have researched the structure, functional relationships and ethnicity along a retail ribbon for a moment in time. Very little, if any attention has been given to their complex relationships over a period of time. Thus, the primary objectives of the study were to examine and determine if Vinton Street in Omaha, Nebraska, is a historic and present-day ethnic retail ribbon, and, furthermore, should time or the evolutionary process be considered as a significant and integral dimension for understanding the city\u27s overall urban retail structure. This study analyzed the historical development of Vinton Street and its adjacent, area, land use classification, location and changes, the ethnic situation of the region and proprietors, plus the mean distance traveled to work by proprietors along Vinton Street for a one hundred year period (1889 to 1989). Each variable served as a chapter that was divided into five time-based stages, Infant through Post Maximal, so comparisons and transitions could be documented for each stage. Then, these stages served as a mechanism to combine this analysis in the final chapter for the conclusion. The results of this geographical analysis indicate that Vinton Street was a historic, ethnic neighborhood retail ribbon that co-exists today as a principal urban arterial ribbon and an ethnic neighborhood retail ribbon. This conclusion was based on such factors as: 1) the direct correlation between the ethnic composition of the study region and the proprietors who operated businesses on the ribbon; 2) the overall ethnic stability of the region and proprietors; 3) the rapid decrease in the number of work-residences found on the artery, as well as within the study region, after its first seventy-years; 4) the consistent increase in the mean distance the proprietor traveled to work; 5) the land use changes from single-function (food and barber/beauty) to urban arterial businesses (furniture, real estate and antique/ variety stores) that are dependent on passing traffic; 6) a larger foreign-population as compared to Omaha throughout the study; and 7) the location and structure of businesses along the principal retail ribbon section of the artery. As a result, the structure and function of an ethnic or urban retail artery evolves or changes through time. A temporal and ethnic focus is indeed a significant dimension that furthers the understanding of the city\u27s overall urban retail structure. Thus, the evolutionary process should be considered an important and integral element in studying the urban retail ribbon, as clearly shown in the Vinton Street study in Omaha, Nebraska

    Quantum effects on Higgs-strahlung events at Linear Colliders within the general 2HDM

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    The associated production of neutral Higgs bosons with the Z gauge boson is investigated in the context of the future linear colliders, such as the ILC and CLIC, within the general two-Higgs-doublet model (2HDM). We compute the corresponding production cross-sections at one-loop, in full consistency with the available theoretical and phenomenological constraints. We find that the wave-function renormalization corrections to the external Higgs fields are the dominant source of the quantum effects, which turn out to be large and negative, and located predominantly in the region around \tan\beta=1 and moderate values of the parameter \lambda_5 (being \lambda_5 < 0). This behavior can be ultimately traced back to the enhancement potential of the triple Higgs boson self-couplings, a trademark feature of the 2HDM with no counterpart in the Higgs sector of the Minimal Supersymmetric Standard Model. The predicted Higgs-strahlung rates comfortably reach a few tens of femtobarn, which means barely 10^3 - 10^4 events per 500 inverse femtobarn of integrated luminosity. Due to their great complementarity, we argue that the combined analysis of the Higgs-strahlung events and the previously computed one-loop Higgs-pair production processes could be instrumental to probe the structure of the Higgs sector at future linac facilities.Comment: LaTeX, 16 pages, 9 Figures, 2 Tables. Extended discussion, references added, matches published version in Phys. Rev.

    Efficient processing of an antigenic sequence for presentation by MHC class I molecules depends on its neighboring residues in the protein

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    Processing of endogenously synthesized proteins generates short peptides that are presented by MHC class I molecules to CD8 T lymphocytes. Here it is documented that not only the sequence of the presented peptide but also the residues by which it is flanked in the protein determine the efficiency of processing and presentation. This became evident when a viral sequence of proven antigenicity was inserted at different positions into an unrelated carrier protein. Not different peptides, but different amounts of the antigenic insert itself were retrieved by isolation of naturally processed peptides from cells expressing the different chimeric proteins. Low yield of antigenic peptide from an unfavorable integration site could be overcome by flanking the insert with oligo-alanine to space it from disruptive neighboring sequences. Notably, the degree of protection against lethal virus disease related directly to the amount of naturally processed antigenic peptide

    Comment on "Deuterium--tritium fusion reactors without external fusion breeding" by Eliezer et al

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    Inclusion of inverse Compton effects in the calculation of deuterium-deuterium burn under the extreme conditions considered by Eliezer et al. [Phys. Lett. A 243 (1998) 298] are shown to decrease the maximum burn temperature from about 300 keV to only 100--150 keV. This decrease is such that tritium breeding by the DD --> T + p reaction is not sufficient to replace the small amount of tritium that is initially added to the deuterium plasma in order to trigger ignition at less than 10 keV.Comment: 6 pages, 1 tabl
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