66,335 research outputs found

    Execution: the Critical “What’s Next?” in Strategic Human Resource Management

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    The Human Resource Planning Society’s 1999 State of the Art/Practice (SOTA/P) study was conducted by a virtual team of researchers who interviewed and surveyed 232 human resource and line executives, consultants, and academics worldwide. Looking three to five years ahead, the study probed four basic topics: (1) major emerging trends in external environments, (2) essential organizational capabilities, (3) critical people issues, and (4) the evolving role of the human resource function. This article briefly reports some of the study’s major findings, along with an implied action agenda – the “gotta do’s for the leading edge. Cutting through the complexity, the general tone is one of urgency emanating from the intersection of several underlying themes: the increasing fierceness of competition, the rapid and unrelenting pace of change, the imperatives of marketplace and thus organizational agility, and the corresponding need to buck prevailing trends by attracting and, especially, retaining and capturing the commitment of world-class talent. While it all adds up to a golden opportunity for human resource functions, there is a clear need to get to get on with it – to get better, faster, and smarter – or run the risk of being left in the proverbial dust. Execute or be executed

    People and guns involved in denied and completed handgun sales

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    Objective: Denial of handgun purchases by prohibited people and knowledge of the structure of gun commerce have helped to deter and prevent firearm violence. The authors hypothesize that handguns involved in a denied purchase would more closely resemble those used in crime compared with handguns sold. Design: Cross sectional. Setting: Denied and completed handgun sales in California, 1998 -- 2000. Main outcome measures: Handgun and purchaser characteristics of denied and completed sales were compared. In particular, handgun characteristics most closely associated with crime guns (type, caliber, barrel length, price) were examined. Results: Compared with handguns sold, handguns in denied sales were somewhat more likely to be semiautomatic pistols (74.6% v 69.4%), to have short barrels (25.9% v 22.2%), and be of medium caliber (48.9% v 37.3%). Ten percent of the handguns in denied sales and 3.4% of handguns sold were identified as inexpensive. Conclusions: The characteristics of denied handguns are similar to those seen among crime guns. Both groups of guns may reflect the desirability for criminal purposes of pistols, which have larger ammunition capacities than other handguns, and short barrels, which increase their ability to be concealed

    Directional genetic differentiation and asymmetric migration

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    Understanding the population structure and patterns of gene flow within species is of fundamental importance to the study of evolution. In the fields of population and evolutionary genetics, measures of genetic differentiation are commonly used to gather this information. One potential caveat is that these measures assume gene flow to be symmetric. However, asymmetric gene flow is common in nature, especially in systems driven by physical processes such as wind or water currents. Since information about levels of asymmetric gene flow among populations is essential for the correct interpretation of the distribution of contemporary genetic diversity within species, this should not be overlooked. To obtain information on asymmetric migration patterns from genetic data, complex models based on maximum likelihood or Bayesian approaches generally need to be employed, often at great computational cost. Here, a new simpler and more efficient approach for understanding gene flow patterns is presented. This approach allows the estimation of directional components of genetic divergence between pairs of populations at low computational effort, using any of the classical or modern measures of genetic differentiation. These directional measures of genetic differentiation can further be used to calculate directional relative migration and to detect asymmetries in gene flow patterns. This can be done in a user-friendly web application called divMigrate-online introduced in this paper. Using simulated data sets with known gene flow regimes, we demonstrate that the method is capable of resolving complex migration patterns under a range of study designs.Comment: 25 pages, 8 (+3) figures, 1 tabl

    Control of unstable steady states by time-delayed feedback methods

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    We show that time-delayed feedback methods, which have successfully been used to control unstable periodic ortbits, provide a tool to stabilize unstable steady states. We present an analytical investigation of the feedback scheme using the Lambert function and discuss effects of both a low-pass filter included in the control loop and non-zero latency times associated with the generation and injection of the feedback signal.Comment: 8 pages, 11 figure

    Infrared Emission from the Radio Supernebula in NGC 5253: A Proto-Globular Cluster?

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    Hidden from optical view in the starburst region of the dwarf galaxy NGC 5253 lies an intense radio source with an unusual spectrum which could be interpreted variously as nebular gas ionized by a young stellar cluster or nonthermal emission from a radio supernova or an AGN. We have obtained 11.7 and 18.7 micron images of this region at the Keck Telescope and find that it is an extremely strong mid-infrared emitter. The infrared to radio flux ratio rules out a supernova and is consistent with an HII region excited by a dense cluster of young stars. This "super nebula" provides at least 15% of the total bolometric luminosity of the galaxy. Its excitation requires 10^5-10^6 stars, giving it the total mass and size (1-2 pc diameter) of a globular cluster. However, its high obscuration, small size, and high gas density all argue that it is very young, no more than a few hundred thousand years old. This may be the youngest globular cluster yet observed.Comment: 6 pages, 2 color figures, Submitted to the ApJL, Revised 4/6/01 based on referee's comment

    Environmental protection of titanium alloys at high temperatures

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    Various concepts were evaluated for protecting titanium alloys from oxygen contamination at 922 K (1200 F) and from hot-salt stress-corrosion at 755 K (900 F). It is indicated that oxygen-contamination resistance can be provided by a number of systems, but for hot-salt stress-corrosion resistance, factors such as coating integrity become very important. Titanium aluminides resist oxygen ingress at 922 K through the formation of alumina (on TiAl3) or modified TiO2 (on Ti3Al, TiAl) scales. TiAl has some resistance to attack by hot salt, but has limited ductility. Ductile Ti-Ni and Ti-Nb-Cr-Al alloys provide limited resistance to oxygen ingress, but are not greatly susceptible to hot-salt stress-corrosion cracking

    Development of high-emittance scales on thoriated nickel-chromium-aluminum-base alloys

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    The surface regions of a DSNiCrAl alloy have been doped, by a pack diffusion process, with small amounts of Mn, Fe, or Co, and the effect of these dopants on the total normal emissivity of the scales produced by subsequent high temperature oxidation has been measured. While all three elements lead to a modest increase in emissivity, (up to 23% greater than the undoped alloy) only the change caused by manganese is thermally stable. However, this increased emissivity is within 85 percent of that of TDNiCr oxidized to form a chromia scale. The maganese-doped alloy is some 50 percent weaker than undoped DSNiCrAl after the doping treatment, and approximately 30 percent weaker after oxidation

    Rocket ozone sounding network data

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    During the period December 1976 through February 1977, three regular monthly ozone profiles were measured at Wallops Flight Center, two special soundings were taken at Antigua, West Indies, and at the Churchill Research Range, monthly activities were initiated to establish stratospheric ozone climatology. This report presents the data results and flight profiles for the period covered

    A formal soundness proof of region-based memory management for object-oriented paradigm.

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    Region-based memory management has been proposed as a viable alternative to garbage collection for real-time applications and embedded software. In our previous work we have developed a region type inference algorithm that provides an automatic compile-time region-based memory management for object-oriented paradigm. In this work we present a formal soundness proof of the region type system that is the target of our region inference. More precisely, we prove that the object-oriented programs accepted by our region type system achieve region-based memory management in a safe way. That means, the regions follow a stack-of-regions discipline and regions deallocation never create dangling references in the store and on the program stack. Our contribution is to provide a simple syntactic proof that is based on induction and follows the standard steps of a type safety proof. In contrast the previous safety proofs provided for other region type systems employ quite elaborate techniques
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