30,243 research outputs found
Outbreak of tropical rat mite (Ornithonyssus bacoti) dermatitis in a home for disabled persons
Five mentally handicapped individuals living in a home for disabled persons in Southern Germany were seen in our outpatient department with pruritic, red papules predominantly located in groups on the upper extremities, neck, upper trunk and face. Over several weeks 40 inhabitants and 5 caretakers were affected by the same rash. Inspection of their home and the sheds nearby disclosed infestation with rat populations and mites. Finally the diagnosis of tropical rat mite dermatitis was made by the identification of the arthropod Ornithonyssus bacoti or so-called tropical rat mite. The patients were treated with topical corticosteroids and antihistamines. After elimination of the rats and disinfection of the rooms by a professional exterminator no new cases of rat mite dermatitis occurred. The tropical rat mite is an external parasite occurring on rats, mice, gerbils, hamsters and various other small mammals. When the principal animal host is not available, human beings can become the victim of mite infestation. Copyright (c) 2007 S. Karger AG, Base
Experimental determination of cosmic ray charged particle intensity profiles in the atmosphere
Absolute cosmic-ray free air ionization and charged particle fluxes and dose rates throughout the atmosphere were measured on a series of balloon flights that commenced in 1968. Argon-filled ionization chambers equipped with solid-state electrometers, with different gas pressures and steel wall thicknesses, and a pair of aluminum-wall Gm counters have provided the basic data. These data are supplemented by measurements with air-filled and tissue equivalent ionization chambers and a scintillation spectrometer. Laboratory experiments together with analyses of the theoretical aspects of the detector responses to cosmic radiation indicate that these profiles can be determined to an overall accuracy of + or - 5 percent
Money in monetary policy design: monetary cross-checking in the New-Keynesian model
In the New-Keynesian model, optimal interest rate policy under uncertainty is formulated without reference to monetary aggregates as long as certain standard assumptions on the distributions of unobservables are satisfied. The model has been criticized for failing to explain common trends in money growth and inflation, and that therefore money should be used as a cross-check in policy formulation (see Lucas (2007)). We show that the New-Keynesian model can explain such trends if one allows for the possibility of persistent central bank misperceptions. Such misperceptions motivate the search for policies that include additional robustness checks. In earlier work, we proposed an interest rate rule that is near-optimal in normal times but includes a cross-check with monetary information. In case of unusual monetary trends, interest rates are adjusted. In this paper, we show in detail how to derive the appropriate magnitude of the interest rate adjustment following a significant cross-check with monetary information, when the New-Keynesian model is the central bank’s preferred model. The cross-check is shown to be effective in offsetting persistent deviations of inflation due to central bank misperceptions. Keywords: Monetary Policy, New-Keynesian Model, Money, Quantity Theory, European Central Bank, Policy Under Uncertaint
Comparative placental morphology and function.
The distinction between histiotrophic nutrition (in which local macromolecules are chiefly responsible for the maintenance of the embryo) and hemotrophic nutrition (which results from a transfer of material between the maternal and fetal circulations) is made. Placentation in a number of commonly used laboratory animals and in man is described, and it is shown that dependence upon histiotroph and hemotroph varies greatly, not only between species but also at different stages of gestation in a single species. These facts are likely to be reflected in considerably differences in response to certain teratogens; they must be carefully considered when experimental results are extrapolated between species. The significance to man of an agent which has been shown to be teratogenic in a single species of experimental animals should be evaluated in terms of possible differences in placental function between man and that species. This is particularly so if there is a suspicion that the potential teratogen may affect the fetal membranes
Underground nuclear power plant siting
This study is part of a larger evaluation of the problems associated with siting nuclear power plants in the next few decades. This evaluation is being undertaken by the Environmental Quality Laboratory of the California Institute of Technology in conjunction with The Aerospace Corporation and several other organizations. Current efforts are directed toward novel approaches to siting plants within the State of California. This report contains the results of efforts performed by The Aerospace Corporation to provide input information to the larger evaluation relative to underground siting of large central station nuclear power plants.
Projections of electric power demand in California and the country as a whole suggest that a major increase in generating capacity will be required. The problem is complicated beyond that of a large but straightforward extension of capital investment by increased emphasis on environmental factors combined with the early stage of commercial application and regulation of nuclear power sources. Hydroelectric power generation is limited by the availability of suitable sites, and fossil fueled plants are constrained by the availability of high quality fuels and the adverse environmental and/or economic impact from the use of more plentiful fuels. A substantial increase in the number of nuclear power plants is now under way. This source of power is expected to provide the maj or portion of increased capacity. Other power sources such as geothermal and nuclear fusion are unlikely to satisfy the national needs due to technical problems and the lack of a comprehensive development program.
There are several problems associated with meeting the projected power demand. Chief among these is the location of acceptable and economic plant sites. Indeed a sufficient number of sites may not be found unless changes occur in the procedures for selecting sites, the criteria for accepting sites, or the type of site required. Placement of a nuclear plant underground has been suggested as an alternative to present siting practices. It is postulated that the advantages of underground siting in some situations may more than compensate for added costs so that such facilities could be preferred even where surface sites are available. By virtue of greater safety, reduced surface area requirements, and improved aesthetics, underground sites might also be found where acceptable surface sites are not available.
Four small European reactors have been constructed partially underground but plans for large size commercial plants have not progressed. Consequently, the features of underground power plant siting are not well understood. Gross physical features such as depth of burial, number and size of excavated galleries, equipment layout, and access or exit shafts/tunnels must be specified. Structural design features of the gallery liners, containment structure, foundations, and gallery interconnections must also be identified. Identification of the nuclear, electrical, and support equipment appropriate to underground operation is needed. Operational features must be defined for normal operations, refueling, and construction. Several magazine articles have been published addressing underground concepts. but adequate engineering data is not available to support an evaluation of the underground concept.
There also remain several unresolved questions relative to the advantages of underground siting as well as the costs and other possible penalties associated with this novel approach to siting. These include the degree of increased safety through improved containment; the extent and value of isolation from falling objects, e. g. aircraft; the value of isolation from surface storms and tidal waves; the value of protection from vandalism or sabotage; the extent by which siting constraints are relieved through reduced population-distance requirements or aggravated by underground construction requirements; and the value to be placed upon the aesthetic differences of a less visible facility.
The study described in this report has been directed toward some of these questions and uncertainties. Within the study an effort has been made to identify viable configurations and structural liners for typical light water reactor nuclear power plants. Three configurations are summarized in Section 3. A discussion of the underground gallery liner design and associated structural analyses is presented in Section 4. Also addressed in the study and discussed in Section 5 are some aspects of containment for underground plants. There it is suggested that the need for large separations between the plant and population centers may be significantly reduced, or perhaps eliminated.
Section 6 contains a brief discussion of operational considerations for underground plants. The costs associated with excavation and lining of the underground galleries have been estimated in Section 7. These estimates include an assessment of variations implied by different seismic loading assumptions and differences in geologic media. It is shown that these costs are a small percentage of the total cost of comparable surface plants. Finally, the parameters characterizing an acceptable underground site are discussed in Section 8. Material is also included in the appendices pertaining to foreign underground plants, span limits of underground excavations, potential siting areas for underground plants in the State of California, pertinent data from the Underground Nuclear Test Program, and other supporting technical discussions
Statistics of unstable periodic orbits of a chaotic dynamical system with a large number of degrees of freedom
For a simple model of chaotic dynamical systems with a large number of
degrees of freedom, we find that there is an ensemble of unstable periodic
orbits (UPOs) with the special property that the expectation values of
macroscopic quantities can be calculated using only one UPO sampled from the
ensemble. Evidence to support this conclusion is obtained by generating the
ensemble by Monte Carlo calculation for a statistical mechanical model
described by a space-time Hamiltonian that is expressed in terms of Floquet
exponents of UPOs. This result allows us to interpret the recent interesting
discovery that statistical properties of turbulence can be obtained from only
one UPO [G. Kawahara and S. Kida, J. Fluid Mech. {\bf 449}, 291 (2001); S. Kato
and M. Yamada, Phys. Rev. E {\bf 68}, 025302(R)(2003)].Comment: 4 pages, 1 figure. In order to clarify generality of our result and
the role of a large number of degrees of freedom, a brief subsection was
adde
Computer model calibration with large non-stationary spatial outputs: application to the calibration of a climate model
Bayesian calibration of computer models tunes unknown input parameters by
comparing outputs with observations. For model outputs that are distributed
over space, this becomes computationally expensive because of the output size.
To overcome this challenge, we employ a basis representation of the model
outputs and observations: we match these decompositions to carry out the
calibration efficiently. In the second step, we incorporate the non-stationary
behaviour, in terms of spatial variations of both variance and correlations, in
the calibration. We insert two integrated nested Laplace
approximation-stochastic partial differential equation parameters into the
calibration. A synthetic example and a climate model illustration highlight the
benefits of our approach
Integrated technology wing design study
The technology development costs and associated benefits in applying advanced technology associated with the design of a new wing for a new or derivative trijet with a capacity for 350 passengers and maximum range of 8519 km, entering service in 1990 were studied. The areas of technology are: (1) airfoil technology; (2) planform parameters; (3) high lift; (4) pitch active control system; (5) all electric systems; (6) E to 3rd power propulsion; (7) airframe/propulsion integration; (8) graphite/epoxy composites; (9) advanced aluminum alloys; (10) titanium alloys; and (11) silicon carbide/aluminum composites. These technologies were applied to the reference aircraft configuration. Payoffs were determined for block fuel reductions and net value of technology. These technologies are ranked for the ratio of net value of technology (NVT) to technology development costs
Generalising the logistic map through the -product
We investigate a generalisation of the logistic map as (, )
where stands for a generalisation of the ordinary product, known as
-product [Borges, E.P. Physica A {\bf 340}, 95 (2004)]. The usual product,
and consequently the usual logistic map, is recovered in the limit ,
The tent map is also a particular case for . The
generalisation of this (and others) algebraic operator has been widely used
within nonextensive statistical mechanics context (see C. Tsallis, {\em
Introduction to Nonextensive Statistical Mechanics}, Springer, NY, 2009). We
focus the analysis for at the edge of chaos, particularly at the
first critical point , that depends on the value of . Bifurcation
diagrams, sensitivity to initial conditions, fractal dimension and rate of
entropy growth are evaluated at , and connections with
nonextensive statistical mechanics are explored.Comment: 12 pages, 23 figures, Dynamics Days South America. To be published in
Journal of Physics: Conference Series (JPCS - IOP
Exciton condensation driving the periodic lattice distortion of 1T-TiSe2
We address the lattice instability of 1T-TiSe2 in the framework of the
exciton condensate phase. We show that, at low temperature, condensed excitons
influence the lattice through electron-phonon interaction. It is found that at
zero temperature, in the exciton condensate phase of 1T-TiSe2, this exciton
condensate exerts a force on the lattice generating ionic displacements
comparable in amplitude to what is measured in experiment. This is thus the
first quantitative estimation of the amplitude of the periodic lattice
distortion observed in 1T-TiSe2 as a consequence of the exciton condensate
phase.Comment: 5 pages, 3 figures and 1 tabl
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