Matching the Local and Cosmic Star Formation Histories

Given the many recent advances in our understanding of the star formation history (SFH) of the Local Group and other nearby galaxies, and in the evolution of star formation with redshift, we present a new comparison of the comoving space density of the star formation rate as a function of look-back time for the Local and Distant Universe. We update the Local SFH derived from the analysis of resolved stellar populations (``fossil records'') in individual nearby galaxies, based on our own estimations as well as available in the literature. While the preliminary comparison of SFHs is found to be broadly consistent, some discrepancies still remain, including an excess of the Local SFR density in the most recent epoch.Comment: 4 pages, slightly revised version from a contribution to 'Galaxies in the Local Volume', Sydney, 8 - 13 July 2007, B. Koribalski and H. Jerjen, ed

Precalving Distribution and Abundance of Barren-Ground Caribou on the Northeastern Mainland of the Northwest Territories

An aerial survey with about 5% coverage of the northeastern mainland, Northwest Territories (342,000 sq. km.) was conducted 5-10 May 1983. We estimated there were 120,000 ± 13,900 caribou (0.35 ± 0.041 caribou/sq km) in the study area. Mean caribou group size ranged from 6 to 11 among nine strata and was correlated (r = 0.81) with stratum caribou density. We found four regions of high caribou density. Three regions coincided with the calving grounds of previously defined herds, the Melville, Wager, and Lorillard, and the fourth suggests a discrete population in the previously unsurveyed area south of the Queen Maud Gulf.Key words: caribou, aerial survey, Rangifer, distribution, abundance, northeastern Northwest TerritoriesMots clés: caribou, inventaire aérien, Rangifer, distribution, abondance, nord-est des Territoires du Nord-Oues

Service operations, the question of productivity and quality

This paper discusses service operations, the question of productivity and quality. It was presented at the 1st joint conference of the production and operation management society and the European operations management association, in 2003

Developments in perfect simulation of Gibbs measures through a new result for the extinction of Galton-Watson-like processes

This paper deals with the problem of perfect sampling from a Gibbs measure with infinite range interactions. We present some sufficient conditions for the extinction of processes which are like supermartingales when large values are taken. This result has deep consequences on perfect simulation, showing that local modifications on the interactions of a model do not affect simulability. We also pose the question to optimize over a class of sequences of sets that influence the sufficient condition for the perfect simulation of the Gibbs measure. We completely solve this question both for the long range Ising models and for the spin models with finite range interactions.Comment: 28 page

Availability and utilization of drug information center, drugs and therapeutic committee and standard treatment guidelines in the management of HIV/AIDS patients at public hospitals in a north-central state, Nigeria

Introduction: Nigerian National Drug Policy has targets with regards to institutionalization of Drug Information Center (DIC), Drugs and Therapeutic Committee (DTC) and Standard Treatment Guidelines (STGs). Inadequate availability and utilization of these supporting policies/documents affect quality of healthcare.Objective: This study examined the availability and utilization of DIC, DTC and STGs in the management of HIV/AIDS patients at public hospitals in a North-Central State, Nigeria.Methods: This qualitative multi-center study involved in-depth interviews of eligible 10 prescribers and 7 dispensers who provided healthcare to HIV/AIDS patients in eligible public hospitals with the aid of structured interview guide. The interviews were audio-taped, verbally transcribed, analyzed and developed into ethnographic summary.Results: Among the prescribers, STGs was the most available and utilized supporting policy/document. Less than 50% of the prescribers had DTC and DIC available in their institutions, less than 50% utilized DTC while only one prescriber utilized the available DIC. Only 10% of the prescribers had and utilized all three (STGs, DTC and DIC). Also, STGs was available to and utilized by all the dispensers. However, only 14.3% of the dispensers had DTC and DIC available in his institution and utilized them. Reasons for utilization/non-utilization of DIC, DTC, and STGs were awareness of availability, patient workload and documentation workload.Conclusion: Availability and utilization of STGs are optimal. However, availability and utilization of DIC and DTC in the management of HIV/AIDS patients in Public Hospitals are below optimal. There is need for improved availability and institutional mechanisms to ensure their utilization.Keywords: Availability, Utilization, Drug Information Center, Drugs and Therapeutic Committee Standard Treatment Guidelines, HIV/AIDS Patient

Synthesis, structural and physical properties of δ′\delta'-FeSe1−x_{1-x}

We report on synthesis, structural characterization, resistivity, magnetic and thermal expansion measurements on the as yet unexplored $\delta'$-phase of FeSe$_{1-x}$, here synthesized under ambient- (AP) and high-pressure (HP) conditions. We show that in contrast to $\beta$-FeSe$_{1-x}$, monophasic superconducting $\delta'$-FeSe$_{1-x}$ can be obtained in off-stoichiometric samples with excess Fe atoms preferentially residing in the van der Waals gap between the FeSe layers. The AP $\delta'$-FeSe$_{1-x}$ sample studied here ($T_c$ $\simeq$ 8.5\,K) possesses an unprecedented residual resistivity ratio RRR $\simeq$ 16. Thermal expansion data reveal a small feature around $\sim$90\,K, which resembles the anomaly observed at the structural and magnetic transitions for other Fe-based superconductors, suggesting that some kind of "magnetic state" is formed also in FeSe. %indicative of a fluctuating magnetic ordering. For HP samples (RRR $\simeq$ 3), the disorder within the FeSe layers is enhanced through the introduction of vacancies, the saturated magnetic moment of Fe is reduced and only spurious superconductivity is observed.Comment: 7 pages, 8 figures, published versio

On Convergence Properties of Shannon Entropy

Convergence properties of Shannon Entropy are studied. In the differential setting, it is shown that weak convergence of probability measures, or convergence in distribution, is not enough for convergence of the associated differential entropies. A general result for the desired differential entropy convergence is provided, taking into account both compactly and uncompactly supported densities. Convergence of differential entropy is also characterized in terms of the Kullback-Liebler discriminant for densities with fairly general supports, and it is shown that convergence in variation of probability measures guarantees such convergence under an appropriate boundedness condition on the densities involved. Results for the discrete setting are also provided, allowing for infinitely supported probability measures, by taking advantage of the equivalence between weak convergence and convergence in variation in this setting.Comment: Submitted to IEEE Transactions on Information Theor

Cartan subalgebras in C*-algebras of Hausdorff etale groupoids

The reduced $C^*$-algebra of the interior of the isotropy in any Hausdorff \'etale groupoid $G$ embeds as a $C^*$-subalgebra $M$ of the reduced $C^*$-algebra of $G$. We prove that the set of pure states of $M$ with unique extension is dense, and deduce that any representation of the reduced $C^*$-algebra of $G$ that is injective on $M$ is faithful. We prove that there is a conditional expectation from the reduced $C^*$-algebra of $G$ onto $M$ if and only if the interior of the isotropy in $G$ is closed. Using this, we prove that when the interior of the isotropy is abelian and closed, $M$ is a Cartan subalgebra. We prove that for a large class of groupoids $G$ with abelian isotropy---including all Deaconu--Renault groupoids associated to discrete abelian groups---$M$ is a maximal abelian subalgebra. In the specific case of $k$-graph groupoids, we deduce that $M$ is always maximal abelian, but show by example that it is not always Cartan.Comment: 14 pages. v2: Theorem 3.1 in v1 incorrect (thanks to A. Kumjain for pointing out the error); v2 shows there is a conditional expectation onto $M$ iff the interior of the isotropy is closed. v3: Material (including some theorem statements) rearranged and shortened. Lemma~3.5 of v2 removed. This version published in Integral Equations and Operator Theor