Elementary zeros of lie algebras of vector fields

WE CONSIDER a finite dimensional Lie algebra ℒ of ϐk (k ≥ 1) differentiable vector fields on a finite dimensional manifold M. A point p ∈ M is a zero for ℒ if X(p) = 0 for very X∈ ℒ. For the classical special case of (the Lie algebra spanned by) a single vector field X, the zero p is said to be elementary (or simple) if the derivative at p of the principal part of X is invertible. The equivalent coordinate-free formulation of this definition is that the vector field, regarded as a map X:M→TM, be transverse to the zero section at p [1]. From this point of view it can be seen that elementary zeros are stable, i.e. they persist under perturbation of X. In addition, such zeros can bc assipncd an index of + I or - I and, when all zeros arc elementary and M is compact, the vector field satisfies the Poincare-Hopf index formula. It is reasonable to ask how these notions should be formulated for zeros of an arbitrary Lie algebra. The correct definition turns out to involve the first Lit algebra cohomology of the linear part of ℒ at p. That the first cohomology is relevant is suggested by results of Hirsch [5, 6] and Stowe [14], which relate stability of stationary points of group actions with the group cohomology of the linear action, and the relationship between the cohomologies of Lit groups and Lie algebras [15]. Section I reviews basic results concerning cohomology of Lie algebras. Section 2 applies these results to the definition and description of elementary zeros for a Lie algebra of vector fields on a manifold. Section 3 contains examples and a result, concerning commuting vector fields on a compact surface, which illustrate limitations to defining an index for a zero of a Lie algebra of vector fields

Communications carrier assembly, model A-3C Final report

Design and fabrication of personal communication system for spacecrew

The Embedded Super Star Cluster of SBS0335-052

We analyze the infrared (6-100 micron) spectral energy distribution of the blue compact dwarf and metal-poor (Z=Z_solar/41) galaxy SBS0335-052. With the help of DUSTY (Ivezic et al. 1999), a program that solves the radiation transfer equations in a spherical environment, we evaluate that the infrared (IR) emission of SBS0335-052 is produced by an embedded super-star cluster (SSC) hidden under 10^5 M_solar of dust, causing 30 mag of visual extinction. This implies that one cannot detect any stellar emission from the 2x10^6 M_solar stellar cluster even at near-infrared (NIR) wavelengths. The derived grain size distribution departs markedly from the widely accepted size distribution inferred for dust in our galaxy (the so-called MRN distribution, Mathis et al. 1977), but resembles what is seen around AGNs, namely an absence of PAH and smaller grains, and grains that grow to larger sizes (around 1 micron). The fact that a significant amount of dust is present in such a low-metallicity galaxy, hiding from UV and optical view most of the star formation activity in the galaxy, and that the dust size distribution cannot be reproduced by a standard galactic law, should be borne in mind when interpreting the spectrum of primeval galaxies.Comment: 32 pages, 3 figures,accepted for publication in A

AF-algebras and topology of mapping tori

A covariant functor from the category of mapping tori to a category of AF-algebras is constructed; the functor takes continuous maps between such manifolds to stable homomorphisms between the corresponding AF-algebras. We use this functor to develop an obstruction theory for the torus bundles of dimension 2, 3 and 4.Comment: to appear Czechoslovak Math.

New Measurement of the Relative Scintillation Efficiency of Xenon Nuclear Recoils Below 10 keV

Liquid xenon is an important detection medium in direct dark matter experiments, which search for low-energy nuclear recoils produced by the elastic scattering of WIMPs with quarks. The two existing measurements of the relative scintillation efficiency of nuclear recoils below 20 keV lead to inconsistent extrapolations at lower energies. This results in a different energy scale and thus sensitivity reach of liquid xenon dark matter detectors. We report a new measurement of the relative scintillation efficiency below 10 keV performed with a liquid xenon scintillation detector, optimized for maximum light collection. Greater than 95% of the interior surface of this detector was instrumented with photomultiplier tubes, giving a scintillation yield of 19.6 photoelectrons/keV electron equivalent for 122 keV gamma rays. We find that the relative scintillation efficiency for nuclear recoils of 5 keV is 0.14, staying constant around this value up to 10 keV. For higher energy recoils we measure a value around 20%, consistent with previously reported data. In light of this new measurement, the XENON10 experiment's results on spin-independent WIMP-nucleon cross section, which were calculated assuming a constant 0.19 relative scintillation efficiency, change from $8.8\times10^{-44}$ cm$^2$ to $9.9\times10^{-44}$ cm$^2$ for WIMPs of mass 100 GeV/c$^2$, and from $4.4\times10^{-44}$ cm$^2$ to $5.6\times10^{-44}$ cm$^2$ for WIMPs of mass 30 GeV/c$^2$.Comment: 8 pages, 8 figure

Human interaction with the divine, the sacred, and the deceased: topics that warrant increased attention by psychologists

Humans have likely been attempting to communicate with entities believed to exist, such as the divine, sacred beings, and deceased people, since the dawn of time. Across cultures and countries, many believe that interaction with the immaterial world is not only possible but a frequent experience. Most religious traditions across the globe focus many rituals and activities around prayer to an entity deemed divine or sacred. Additionally, many people–religious, agnostic, and atheists alike–report communication with their departed loved ones. During highly stressful times associated with natural disasters, war, pandemics, and other threats to human life, the frequency and intensity of these activities and associated experiences substantially increase. Although this very human phenomenon seems to be universal, the empirical literature on the topic within psychology is thin. This paper discussed the topic and reviews what we know from the professional literature about how people perceive communication with these unseen entities. It highlights the perceptual and social cognition evidence and discussed the role of attribution theory, which might help us understand the beliefs, motivations, and practices of those engaged with communication with the unseen. Empirical laboratory research with mediums is discussed as well, examining the evidence for communication with the deceased. Final reflections and suggestions for future research are also offered

Performance of a cryogenic system prototype for the XENON1T Detector

We have developed an efficient cryogenic system with heat exchange and associated gas purification system, as a prototype for the XENON1T experiment. The XENON1T detector will use about 3 ton of liquid xenon (LXe) at a temperature of 175K as target and detection medium for a dark matter search. In this paper we report results on the cryogenic system performance focusing on the dynamics of the gas circulation-purification through a heated getter, at flow rates above 50 Standard Liter per Minute (SLPM). A maximum flow of 114 SLPM has been achieved, and using two heat exchangers in parallel, a heat exchange efficiency better than 96% has been measured

3D Position Sensitive XeTPC for Dark Matter Search

The technique to realize 3D position sensitivity in a two-phase xenon time projection chamber (XeTPC) for dark matter search is described. Results from a prototype detector (XENON3) are presented.Comment: Presented at the 7th UCLA Symposium on "Sources and Detection of Dark Matter and Dark Energy in the Universe

Religious faith and psychosocial adaptation among stroke patients in Kuwait: A mixed method study

This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ 2012 Springer Science+Business Media.Religious faith is central to life for Muslim patients in Kuwait, so it may influence adaptation and rehabilitation. This study explored quantitative associations among religious faith, self-efficacy, and life satisfaction in 40 female stroke patients and explored the influence of religion within stroke rehabilitation through qualitative interviews with 12 health professionals. The quantitative measure of religious faith did not relate to life satisfaction or self-efficacy in stroke patients. However, the health professionals described religious coping as influencing adaptation post-stroke. Fatalistic beliefs were thought to have mixed influences on rehabilitation. Measuring religious faith among Muslims through a standardized scale is debated. The qualitative accounts suggest that religious beliefs need to be acknowledged in stroke rehabilitation in Kuwait