Mapping the stability field of Jupiter Trojans

Jupiter Trojans are a remnant of outer solar system planetesimals captured into stable or quasistable libration about the 1:1 resonance with the mean motion of Jupiter. The observed swarms of Trojans may provide insight into the original mass of condensed solids in the zone from which the Jovian planets accumulated, provided that the mechanisms of capture can be understood. As the first step toward this understanding, the stability field of Trojans were mapped in the coordinate proper eccentricity, e(sub p), and libration amplitude, D. To accomplish this mapping, the orbits of 100 particles with e(sub p) in the range of 0 to 0.8 and D in the range 0 to 140 deg were numerically integrated. Orbits of the Sun, the four Jovian planets, and the massless particles were integrated as a full N-body system, in a barycentric frame using fourth order symplectic scheme

Fatigue in celiac disease: A review of the literature

Fatigue is increasingly recognized as a significant problem in patients with chronic inflammatory and autoimmune diseases. In celiac disease, a chronic immune‐mediated disease triggered by dietary gluten, conflicting opinions exist regarding both the size of the problem and the effect of a gluten‐free diet (GFD) on fatigue. We reviewed the existing literature regarding fatigue in celiac disease. We conducted a systematic search in the Embase, Ovid Medline, and Cochrane databases using subject terms from controlled vocabularies. Articles were reviewed based on language, type of article, title, and abstract or full text. Eighteen articles were finally selected for review. Fatigue was significantly greater in patients with celiac disease compared to healthy control subjects. Fatigue prevalence ranged from 8 to 100%. Fatigue severity was assessed in six studies. The fatigue visual analogue scale was the most frequently used fatigue instrument with scores from 57 to 79 prior to starting a GFD and from 39 to 59 in patients on a GFD. Seven studies investigated the effect of a GFD on fatigue, including five studies that reported less fatigue while on the diet and two studies that showed no significant difference. This review concludes that fatigue is a substantial complaint in patients with celiac disease. A GFD seems to reduce fatigue, but existing data are limited.publishedVersio

Housing flexibility effects on rotor stability

Preliminary rotordynamic evaluations are performed with a housing stiffness assumption that is typically determined only after the hardware is built. In addressing rotor stability, a rigid housing assumption was shown to predict an instability at a lower spin speed than a comparable flexible housing analysis. This rigid housing assumption therefore provides a conservative estimate of the stability threshold speed. A flexible housing appears to act as an energy absorber and dissipated some of the destabilizing force. The fact that a flexible housing is usually asymmetric and considerably heavier than the rotor was related to this apparent increase in rotor stability. Rigid housing analysis is proposed as a valuable screening criteria and may save time and money in construction of elaborate housing finite element models for linear stability analyses

Synthesis of aromatic secondary diamines

A series of N-methyl substituted aromatic polyamides derived from the secondary aromatic diamines, 4,4'-bis(methylamino)diphenylmethane, 3,3'-bis(methylamino) diphenylmethane, 4,4'-bis(methylamino)benzophenone or 3,3'-bis(methylamino)benzophenone and isophthaloyl dichloride, terphthaloyl dichloride or 3,3'diphenylmethane dicarboxylic acid dichloride was prepared by high temperature solution polymerization in s-tetrachloroethane. Compared to analogous unsubstituted and partially N-methylated aromatic polyamides, the full N-methylated polyamides exhibited significantly lower glass transition temperatures, reduced crystallinity, improved thermal stability and good solubility in chlorinated solvents

Asteroid flux and impact cratering rate on Venus

By the end of 1990, 65 Venus-crossing asteroids were recognized; these represent 59 percent of the known Earth-crossing asteroids. Further studies, chiefly numerical integrations of orbit evolution, may reveal one or two more Venus crossers among the set of discovered asteroids. A Venus crosser was defined as an asteroid whose orbit can intersect the orbit of Venus as a result of secular (long range) perturbations. Venus crossers revolving on orbits that currently overlap the orbit of Venus are called Venapol asteroids, and those on orbit that don't overlap are called Venamor asteroids; 42 Venapols and 23 Venamors were recognized. Collision probabilities with Venus for 60 of the known Venus crossers were determined

The Evolution of Luminous Compact Blue Galaxies: Disks or Spheroids?

Luminous compact blue galaxies (LCBGs) are a diverse class of galaxies characterized by high luminosities, blue colors, and high surface brightnesses. Residing at the high luminosity, high mass end of the blue sequence, LCBGs sit at the critical juncture of galaxies that are evolving from the blue to the red sequence. Yet we do not understand what drives the evolution of LCBGs, nor how they will evolve. Based on single-dish HI observations, we know that they have a diverse range of properties. LCBGs are HI-rich with M(HI)=10^{9-10.5} M(sun), have moderate M(dyn)=10^{10-12} M(sun), and 80% have gas depletion timescales less than 3 Gyr. These properties are consistent with LCBGs evolving into low-mass spirals or high mass dwarf ellipticals or dwarf irregulars. However, LCBGs do not follow the Tully-Fisher relation, nor can most evolve onto it, implying that many LCBGs are not smoothly rotating, virialized systems. GMRT and VLA HI maps confirm this conclusion revealing signatures of recent interactions and dynamically hot components in some local LCBGs, consistent with the formation of a thick disk or spheroid. Such signatures and the high incidence of close companions around LCBGs suggest that star formation in local LCBGs is likely triggered by interactions. The dynamical masses and apparent spheroid formation in LCBGs combined with previous results from optical spectroscopy are consistent with virial heating being the primary mechanism for quenching star formation in these galaxies.Comment: 4 pages, 1 figure, to appear in "Hunting for the Dark: The Hidden Side of Galaxy Formation", Malta, 19-23 Oct. 2009, eds. V.P. Debattista & C.C. Popescu, AIP Conf. Se

The kinetic temperature in a damped Lyman-alpha absorption system in Q2206-199 - an example of the warm neutral medium

By comparing the widths of absorption lines from OI, SiII and FeII in the redshift z=2.076 single-component damped Lyman alpha absorption system in the spectrum of Q2206-199 we establish that these absorption lines arise in Warm Neutral Medium gas at ~12000 +/- 3000K. This is consistent with thermal equilibrium model estimates of ~ 8000K for the Warm Neutral Medium in galaxies, but not with the presence of a significant cold component. It is also consistent with, but not required by, the absence of CII* fine structure absorption in this system. Some possible implications concerning abundance estimates in narrow-line WNM absorbers are discussed.Comment: 9 pages, 3 figures. MNRAS accepte

New Quantum Bounds for Inequalities involving Marginal Expectations

We review, correct, and develop an algorithm which determines arbitrary Quantum Bounds, based on the seminal work of Tsirelson [Lett. Math. Phys. 4, 93 (1980)]. The potential of this algorithm is demonstrated by deriving both new number-valued Quantum Bounds, as well as identifying a new class of function-valued Quantum Bounds. Those results facilitate an 8-dimensional Volume Analysis of Quantum Mechanics which extends the work of Cabello [PRA 72 (2005)]. We contrast the Quantum Volume defined be these new bounds to that of Macroscopic Locality, defined by the inequalities corresponding to the first level of the hierarchy of Navascues et al [NJP 10 (2008)], proving our function-valued Quantum Bounds to be more complete.Comment: 6 pages. Now includes appendices containing a pseudo-code formulation of the algorithm as well as a discussion of general physical symmetries. A new lower bound to the quantum volume has been derived, and an error in the mapping of physical observables to variational parameters has been correcte