Faint blue objects on the Hubble Deep Field North & South as possible nearby old halo white dwarfs

Using data derived from the deepest and finest angular resolution images of the universe yet acquired by astronomers at optical wavelengths using the Hubble Space Telescope (HST) in two postage-stamp sections of the sky (Williams et al. 1996a,b), plus simple geometrical and scaling arguments, we demonstrate that the faint blue population of point-source objects detected on those two fields (M\'endez et al. 1996) could actually be ancient halo white dwarfs at distances closer than about 2 kpc from the Sun. This finding has profound implications, as the mass density of the detected objects would account for about half of the missing dark matter in the Milky-Way (Bahcall and Soneira 1980), thus solving one of the most controversial issues of modern astrophysics (Trimble 1987, Ashman 1992). The existence of these faint blue objects points to a very large mass locked into ancient halo white dwarfs. Our estimate indicates that they could account for as much as half of the dark matter in our Galaxy, confirming the suggestions of the MACHO microlensing experiment (Alcock et al. 1997). Because of the importance of this discovery, deep follow-up observations with HST within the next two years would be needed to determine more accurately the kinematics (tangential motions) for these faint blue old white dwarfs.Comment: Accepted for publication on The Astrophysical Journal, Part 1. 8 pages (AAS Latex macros V4.0), 1 B&W postscript figure, 2 color postscript figure

The Probabilistic Representative Values

In this paper we define a new family of solutions for the class of cooperative games with transferable utility, in which the set of players exhibits a structure of a priori unions.This family is deeply connected with the Shapley value for games with transferable utility but, moreover, we assume a solidarity strong connection among all the components of each union.As a consequence of this, they are disposed to delegate one coalition of members of the union to negotiate with the other unions, and, therefore, each union will have a representative coalition.Furthermore, three interesting solutions that belong to this family of values are studied, as well as the non cooperative selection of the best representative coalition for each union.TU-games with unions;Shapley value;representative coalition

A conformational RNA zipper promotes intron ejection during non-conventional XBP1 mRNA splicing.

The kinase/endonuclease IRE1 is the most conserved signal transducer of the unfolded protein response (UPR), an intracellular signaling network that monitors and regulates the protein folding capacity of the endoplasmic reticulum (ER). Upon sensing protein folding perturbations in the ER, IRE1 initiates the unconventional splicing of XBP1 mRNA culminating in the production of the transcription factor XBP1s, which expands the ER's protein folding capacity. We show that an RNA-intrinsic conformational change causes the intron of XBP1 mRNA to be ejected and the exons to zipper up into an extended stem, juxtaposing the RNA ends for ligation. These conformational rearrangements are important for XBP1 mRNA splicing in vivo. The features that point to such active participation of XBP1 mRNA in the splicing reaction are highly conserved throughout metazoan evolution, supporting their importance in orchestrating XBP1 mRNA processing with efficiency and fidelity

The Two-stage Constrained Equal Awards and Losses Rules for Multi-Issue Allocation Situation

This paper considers two-stage solutions for multi-issue allocation situations.Characterisations are provided for the two-stage constrained equal awards and constrained equal losses rules, based on the properties of composition and path independence.multi-issue allocation situations;constrained equal awards;constrained equal losses;two-stage solutions

Litigation and Settlement: New Evidence from Labor Courts in Mexico

Using a newly assembled data set on procedures filed in Mexican labor tribunals, we study the determinants of final awards to workers. On average, workers recover less than 30% of their claim. Our strongest result is that workers receive higher percentages of their claims in settlements than in trial judgments. We also find that cases with multiple claimants against a single firm are less likely to be settled, which partially explains why workers involved in these procedures receive lower percentages of their claims. Finally, we find evidence that a worker who exaggerates her claim is less likely to settle.

Litigation and settlement : new evidence from labor courts in Mexico

Using a newly assembled data set on procedures filed in Mexican labor tribunals, the authors of this paper study the determinants of final awards to workers. On average, workers recover less than 30 percent of their claim. The strongest result is that workers receive higher percentages of their claims in settlements than in trial judgments. It is also found that cases with multiple claimants against a single firm are less likely to be settled, which partially explains why workers involved in these procedures receive lower percentages of their claims. Finally, the authors find evidence that a worker who exaggerates his or her claim is less likely to settle.Bankruptcy and Resolution of Financial Distress,Arbitration,Information Security&Privacy,Labor Markets,Judicial System Reform

Implementing a Patient Hand-Hygiene Protocol to Decrease \u3cem\u3eClostridium Difficile\u3c/em\u3e Infections in the Acute Care Setting

PURPOSE: The purpose of this study was to develop and implement a patient hand hygiene protocol (PHHP) to improve patient outcomes, specifically to decrease the rates of clostridium difficile infections (CDI) at Norton Hospital (NH) and Norton Audubon Hospital (NAH) in Louisville, Kentucky. METHODS: This was a multi-center, quasi-experimental study that implemented a PHHP on three units at two hospitals in the Norton Healthcare system. The sample consisted of 159 patients in the pre-intervention period and 18 patients in the intervention period. A retrospective records review was performed to analyze specific demographic variables. RESULTS: No differences in age and gender were found between the pre-intervention and intervention groups. The groups showed no difference in gastric antacid and antibiotic usage, prior to and during admission. A control chart illustrated CDI rates between NH and NAH for a 21-month time period. Both facilities demonstrated common cause variation with no significant trends. CONCLUSION: CDI development is multifaceted; Risks include age, diagnoses, comorbidities, and need for antibiotics. CDI rates at NH and NAH were variable and unpredictable, indicating a need for extensive research into additional preventative measures. Engaging patients and families in hand hygiene can strengthen knowledge and attitudes about hospital acquired infection prevention

Does bisphenol-A, an estrogen-like environmental toxin, disrupt expression of the neuronal chloride exporter protein during early brain development?

Bisphenol A (BPA), a manufactured compound found in consumer products, is known to adversely affect early brain development by disrupting normal estrogen signaling. Recently, BPA was reported to suppress expression of a gene encoding the neuron-specific chloride ion transporter, KCC2. Human and animal studies show suppressing KCC2 can cause neuronal and behavioral hyperactivity. Therefore, some adverse effects of BPA may be due to KCC2 suppression and consequent neuronal hyperactivity. This study aimed to determine whether BPA exposure during brain development alters KCC2 expression. A secondary purpose was to evaluate whether a new transgenic zebrafish line, KCC2:mCitrine,could be used to track changes in KCC2 expression in vivo by fluorescence imaging. Zebrafish embryos treated with 2.5µM BPA during days 0-5 post-fertilization were tested for (1) KCC2:mCitrine fluorescence brightness; (2) KCC2 gene expression using RT qPCR as an external validation for fluorescence; (3) Behavioral activity level, and; (4) estrogen signaling, as a BPA manipulation check. Results showed that BPA produced expected estrogenic effects in the developing brain and decreased KCC2 expression at specific developmental time points. However, BPA did not produce expected behavioral hyperactivity. Lastly, RT-qPCR data were uninterpretable so fluorescence brightness could not be externally validated as a measure of gene expression. This pattern of results supports the conclusion that estrogenic effects of BPA can suppress KCC2 expression in developing zebrafish brains, consistent with previous research implicating BPA as a teratogen, and KCC2 expression as a mechanism -- and potential treatment target -- in human developmental disorders

The Circumstellar Extinction of Planetary Nebulae

We analyze the dependence of circumstellar extinction on core mass for the brightest planetary nebulae (PNe) in the Magellanic Clouds and M31. We show that in all three galaxies, a statistically significant correlation exists between the two quantities, such that high core mass objects have greater extinction. We model this behavior, and show that the relation is a simple consequence of the greater mass loss and faster evolution times of high mass stars. The relation is important because it provides a natural explanation for the invariance of the [O III] 5007 planetary nebula luminosity function (PNLF) with population age: bright Population I PNe are extinguished below the cutoff of the PNLF. It also explains the counter-intuitive observation that intrinsically luminous Population I PNe often appear fainter than PNe from older, low-mass progenitors.Comment: 12 pages, 2 figures, accepted for ApJ, April 10, 199