30,357 research outputs found
Narrow Technihadron Production at the First Muon Collider
In modern technicolor models, there exist very narrow spin-zero and spin-one
neutral technihadrons---, and ---with masses of a
few 100 GeV. The large coupling of to , the direct
coupling of and to the photon and , and the superb
energy resolution of the First Muon Collider may make it possible to resolve
these technihadrons and produce them at extraordinarily large rates.Comment: 11 pages, latex, including 2 postscript figure
Estimation of Apollo lunar dust transport using optical extinction measurements
A technique to estimate mass erosion rate of surface soil during landing of
the Apollo Lunar Module (LM) and total mass ejected due to the rocket plume
interaction is proposed and tested. The erosion rate is proportional to the
product of the second moment of the lofted particle size distribution N(D), and
third moment of the normalized soil size distribution S(D), divided by the
integral of S(D)D^2/v(D), where D is particle diameter and v(D) is the vertical
component of particle velocity. The second moment of N(D) is estimated by
optical extinction analysis of the Apollo cockpit video. Because of the
similarity between mass erosion rate of soil as measured by optical extinction
and rainfall rate as measured by radar reflectivity, traditional NWS
radar/rainfall correlation methodology can be applied to the lunar soil case
where various S(D) models are assumed corresponding to specific lunar sites.Comment: Acta Geophysica 201
FTY720 (fingolimod) modulates the severity of viral-induced encephalomyelitis and demyelination.
BackgroundFTY720 (fingolimod) is the first oral drug approved by the Food and Drug Administration for treatment of patients with the relapsing-remitting form of the human demyelinating disease multiple sclerosis. Evidence suggests that the therapeutic benefit of FTY720 occurs by preventing the egress of lymphocytes from lymph nodes thereby inhibiting the infiltration of disease-causing lymphocytes into the central nervous system (CNS). We hypothesized that FTY720 treatment would affect lymphocyte migration to the CNS and influence disease severity in a mouse model of viral-induced neurologic disease.MethodsMice were infected intracranially with the neurotropic JHM strain of mouse hepatitis virus. Infected animals were treated with increasing doses (1, 3 and 10 mg/kg) of FTY720 and morbidity and mortality recorded. Infiltration of inflammatory virus-specific T cells (tetramer staining) into the CNS of FTY720-treated mice was determined using flow cytometry. The effects of FTY720 treatment on virus-specific T cell proliferation, cytokine production and cytolytic activity were also determined. The severity of neuroinflammation and demyelination in FTY720-treated mice was examined by flow cytometry and histopathologically, respectively, in the spinal cords of the mice.ResultsAdministration of FTY720 to JHMV-infected mice resulted in increased clinical disease severity and mortality. These results correlated with impaired ability to control viral replication (P < 0.05) within the CNS at days 7 and 14 post-infection, which was associated with diminished accumulation of virus-specific CD4+ and CD8+ T cells (P < 0.05) into the CNS. Reduced neuroinflammation in FTY720-treated mice correlated with increased retention of T lymphocytes within draining cervical lymph nodes (P < 0.05). Treatment with FTY720 did not affect virus-specific T cell proliferation, expression of IFN-γ, TNF-α or cytolytic activity. FTY720-treated mice exhibited a reduction in the severity of demyelination associated with dampened neuroinflammation.ConclusionThese findings indicate that FTY720 mutes effective anti-viral immune responses through impacting migration and accumulation of virus-specific T cells within the CNS during acute viral-induced encephalomyelitis. FTY720 treatment reduces the severity of neuroinflammatory-mediated demyelination by restricting the access of disease-causing lymphocytes into the CNS but is not associated with viral recrudescence in this model
WWII and Long Run Convergence in the OECD
Existing evidence for unconditional convergence in the OECD is mixed, and depends largely on whether time series or cross sectional methods are used. In this paper we reconsider the evidence for unconditional convergence by dividing the long run data into several subperiods. We use a two stage approach in this work. We first model the growth rate of output directly and use this model to estimate the long-run growth rate for the countries in our sample. We then use the estimates of long-run growth in output to test for unconditional convergence and to test for equality of long-run growth across countries. GLS is used to explicitly take into account the sampling uncertainty inherent in our estimates of the long-run growth rate we found in the first stage of the process. The results show strong evidence for unconditional convergence in the post WWII period 1951-1974, but no evidence of convergence in the periods preceding or following this period. Moreover, it is di±cult to reject the hypothesis that most of the countries in our sample had the same growth rate outside of this period. Thus find little evidence to suggest that absolute convergence has been a continuous long run process, and some evidence for the view that national policies mainly affect income levels rather than growth rateGrowth, Convergence, Technological Change
Users manual for the Automated Performance Test System (APTS)
The characteristics of and the user information for the Essex Automated Performance Test System (APTS) computer-based portable performance assessment battery are given. The battery was developed to provide a menu of performance test tapping the widest possible variety of human cognitive and motor functions, implemented on a portable computer system suitable for use in both laboratory and field settings for studying the effects of toxic agents and other stressors. The manual gives guidance in selecting, administering and scoring tests from the battery, and reviews the data and studies underlying the development of the battery. Its main emphasis is on the users of the battery - the scientists, researchers and technicians who wish to examine changes in human performance across time or as a function of changes in the conditions under which test data are obtained. First the how to information needed to make decisions about where and how to use the battery is given, followed by the research background supporting the battery development. Further, the development history of the battery focuses largely on the logical framework within which tests were evaluated
Issues in development, evaluation, and use of the NASA Preflight Adaptation Trainer (PAT)
The Preflight Adaptation Trainer (PAT) is intended to reduce or alleviate space adaptation syndrome by providing opportunities for portions of that adaptation to occur under normal gravity conditions prior to space flight. Since the adaptation aspects of the PAT objectives involve modification not only of the behavior of the trainee, but also of sensiomotor skills which underly the behavioral generation, the defining of training objectives of the PAT utilizes four mechanisms: familiarization, demonstration, training and adaptation. These mechanisms serve as structural reference points for evaluation, drive the content and organization of the training procedures, and help to define the roles of the PAT instructors and operators. It was determined that three psychomotor properties are most critical for PAT evaluation: reliability; sensitivity; and relevance. It is cause for concern that the number of measures available to examine PAT effects exceed those that can be properly studied with the available sample sizes; special attention will be required in selection of the candidate measure set. The issues in PAT use and application within a training system context are addressed through linking the three training related mechanisms of familiarization, demonstration and training to the fourth mechanism, adaptation
Vacuum Alignment in Technicolor Theories-I. The Technifermion Sector
We have carried out numerical studies of vacuum alignment in technicolor
models of electroweak and flavor symmetry breaking. The goal is to understand
alignment's implications for strong and weak CP nonconservation in quark
interactions. In this first part, we restrict our attention to the
technifermion sector of simple models. We find several interesting phenomena,
including (1) the possibility that all observable phases in the technifermions'
unitary vacuum-alignment matrix are integer multiples of \pi/N' where N' \le N,
the number of technifermion doublets, and (2) the possibility of exceptionally
light pseudoGoldstone technipions.Comment: 19 pages, Latex with one postscript figur
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