54,424 research outputs found
Design of a monitor and simulation terminal (master) for space station telerobotics and telescience
Based on Space Station and planetary spacecraft communication time delays and bandwidth limitations, it will be necessary to develop an intelligent, general purpose ground monitor terminal capable of sophisticated data display and control of on-orbit facilities and remote spacecraft. The basic elements that make up a Monitor and Simulation Terminal (MASTER) include computer overlay video, data compression, forward simulation, mission resource optimization and high level robotic control. Hardware and software elements of a MASTER are being assembled for testbed use. Applications of Neural Networks (NNs) to some key functions of a MASTER are also discussed. These functions are overlay graphics adjustment, object correlation and kinematic-dynamic characterization of the manipulator
Understanding Hope: A Review of Measurement and Construct Validity Research
Hope has been discussed by philosophers, theologians, educators, and scientists, to name but a few groups of people, over the preceding two millennia. During the last 15 years, C. R. Snyder and his colleagues at the University of Kansas have developed a theory and associated measures of the hope construct that have received extensive, detailed attention both within and outside the field of psychology. In this chapter, we describe Snyder\u27s hope model and some of the research findings that have supported the validity of this construct. Beginning with a conceptual definition of hope, we move to relevant findings about the usefulness of hope in the lives of individuals in various life arenas. We describe measures developed for assessing hope in children and adults, as well as current issues associated with the validity of hope measurement. Finally, we discuss future directions for further investigation of hope
SUSY signals at HERA in the no-scale flipped SU(5) supergravity model
Sparticle production and detection at HERA are studied within the recently
proposed no-scale flipped supergravity model. Among the various
reaction channels that could lead to sparticle production at HERA, only the
following are within its limit of sensitivity in this model: , where are the
two lightest neutralinos and is the lightest chargino. We study the
elastic and deep-inelastic contributions to the cross sections using the
Weizs\"acker-Williams approximation. We find that the most promising
supersymmetric production channel is right-handed selectron ()
plus first neutralino (), with one hard electron and missing energy
signature. The channel leads to comparable rates but also
allows jet final states. A right-handedly polarized electron beam at HERA would
shut off the latter channel and allow preferentially the former one. With an
integrated luminosity of {\cal L}=100\ipb, HERA can extend the present LEPI
lower bounds on by
\approx25\GeV, while {\cal L}=1000\ipb will make HERA competitive with
LEPII. We also show that the Leading Proton Spectrometer (LPS) at HERA is an
excellent supersymmetry detector which can provide indirect information about
the sparticle masses by measuring the leading proton longitudinal momentum
distribution.Comment: 11 pages, 8 figures (available upon request as uuencoded file or
separate ps files), tex (harvmac) CTP-TAMU-15/93, CERN/LAA/93-1
Disk stars in the Milky Way detected beyond 25 kpc from its center
CONTEXT. The maximum size of the Galactic stellar disk is not yet known. Some
studies have suggested an abrupt drop-off of the stellar density of the disk at
Galactocentric distances kpc, which means that in practice no
disk stars or only very few of them should be found beyond this limit. However,
stars in the Milky Way plane are detected at larger distances. In addition to
the halo component, star counts have placed the end of the disk beyond 20 kpc,
although this has not been spectroscopically confirmed so far.
AIMS. Here, we aim to spectroscopically confirm the presence of the disk
stars up to much larger distances.
METHODS. With data from the LAMOST and SDSS-APOGEE spectroscopic surveys, we
statistically derived the maximum distance at which the metallicity
distribution of stars in the Galactic plane is distinct from that of the halo
populations.
RESULTS. Our analysis reveals the presence of disk stars at R>26 kpc (99.7%
C.L.) and even at R>31 kpc (95.4% C.L.).Comment: 4 pages, accepted to be published in A&A-Letter
Topological Correlations in a Layer Adsorbed on a Crystal Surface
The incoherent scattering of electrons by a layer adsorbed at a single crystal surface is
determined by the topological correlations of elements forming the adsorbed layer. The model for the
description of atoms or molecules adsorbed on the surface is formulated in terms of occupation
operators which are expressed in terms of pseudospin operators with a given spin value. The
correlations can be determined by the fluctuation dissipation theorem in connection with the
susceptibility or given directly by means of the Green functions properly chosen. An example of the
topological or chemical disorder of two components is considered in detail. The calculations of the
topological correlations allow us to find the incoherent scattering amplitude as a function of the
surface coverage which can be experimentally detected.Zadanie pt. „Digitalizacja i udostępnienie w Cyfrowym Repozytorium Uniwersytetu Łódzkiego kolekcji czasopism naukowych wydawanych przez Uniwersytet Łódzki” nr 885/P-DUN/2014 zostało dofinansowane ze środków MNiSW w ramach działalności upowszechniającej naukę
Olfactory variation in mouse husbandry and its implications for refinement and standardisation: UK survey of non-animal scents
With their highly sensitive olfactory system, the behaviour and physiology of mice are not only influenced by the scents of conspecifics and other species, but also by many other chemicals in the environment. The constraints of laboratory housing limit a mouse’s capacity to avoid aversive odours that could be present in the environment. Potentially odorous items routinely used for husbandry procedures, such as sanitizing products and gloves, could be perceived by mice as aversive or attractive, and affect their behaviour, physiology and experimental results. A survey was sent to research institutions in the UK to enquire about husbandry practices that could impact on the olfactory environment of the mouse. Responses were obtained from 80 individuals working in 51 institutions. Husbandry practices varied considerably. Seventy percent of respondents reported always wearing gloves for handling mice, with nitrile being the most common glove material (94%) followed by latex (23%) and vinyl (14%). Over six different products were listed for cleaning surfaces, floors, anaesthesia and euthanasia chambers and behavioural apparatus. In all cases Trigene™ (now called Anistel™) was the most common cleaning product used (43, 41, 40 and 49%, respectively). Depending on the attribute considered, between 7 and 19% of respondents thought that cleaning products definitely, or were likely to, have strong effects on standardization, mouse health, physiology or behaviour. Understanding whether and how these odours affect mouse welfare will help to refine mouse husbandry and experimental procedures through practical recommendations, to improve the quality of life of laboratory animals and the experimental data obtained
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