1,654 research outputs found
Hormones and Their Actions, Part II Edited by B.A. Cooke, R.J.B. King and H.J. van der Molen; Elsevier; Amsterdam, 1988; xv + 366 pages; $123.75; Dfl.235.00
Wage/Tenure Contracts with Heterogeneous Firms
This paper investigates equilibria in a labor market where heterogeneous firms post wage/tenure contracts and risk-averse workers, both employed and unemployed, search for new job opportunities. Different firms, even those with the same productivity, typically offer different contracts. Equilibrium finds workers never quit from higher productivity firms to lower productivity firms, but turnover is inefficiently low as employees with large tenures at low productivity firms may reject job offers from more productive firms. A worker who quits to a more productive firm may take a wage cut in anticipation of better wage promotion prospects. Wages within a firm might also increase by a discrete amount at the end of an initial 'probationary' spell
Electronic structure and the glass transition in pnictide and chalcogenide semiconductor alloys. Part II: The intrinsic electronic midgap states
We propose a structural model that treats in a unified fashion both the
atomic motions and electronic excitations in quenched melts of pnictide and
chalcogenide semiconductors. In Part I (submitted to J. Chem. Phys.), we argued
these quenched melts represent aperiodic -networks that are highly
stable and, at the same time, structurally degenerate. These networks are
characterized by a continuous range of coordination. Here we present a
systematic way to classify these types of coordination in terms of discrete
coordination defects in a parent structure defined on a simple cubic lattice.
We identify the lowest energy coordination defects with the intrinsic midgap
electronic states in semiconductor glasses, which were argued earlier to cause
many of the unique optoelectronic anomalies in these materials. In addition,
these coordination defects are mobile and correspond to the transition state
configurations during the activated transport above the glass transition. The
presence of the coordination defects may account for the puzzling discrepancy
between the kinetic and thermodynamic fragility in chalcogenides. Finally, the
proposed model recovers as limiting cases several popular types of bonding
patterns proposed earlier, including: valence-alternation pairs, hypervalent
configurations, and homopolar bonds in heteropolar compounds.Comment: 17 pages, 15 figures, revised version, final version to appear in J.
Chem. Phy
OntoCAT - a simpler way to access ontology resources
OntoCAT is an open source package developed to simplify the task of querying heterogeneous ontology resources. It supports local ontologies in OBO and OWL format as well as public repositories NCBO BioPortal and EBI Ontology Lookup Service (OLS). It is available from "http://ontocat.sourceforge.net":http://ontocat.sourceforge.ne
The Method of Moments and the Energy Levels of Molecules and Solids
The method of moments is used to derive the energy levels
of a representative series of molecules, crystalline and noncrysta-1-
line solids. It provides a direct link between the density of states
of the eigenvalue spectrum and the connectivity and topology of
the molecular or solid state network
Is Hot IT a False Economy? An Analysis of Server and Data Center Energy Efficiency as Temperatures Rise
As demand for digital services grows, there is need to improve efficiency and reduce the environmental impact of data centers. The largest energy consumer in any data center is the IT, followed by the systems dedicated to cooling. Aiming to improve efficiency, and driven by metrics like PUE, there is a trend towards running data centers hotter to reduce the cooling energy. There is little research investigating the effect this will have on the IT beyond failure rates. To ensure overall efficiency is improving, we must view the data center as a system of systems, taking a holistic view rather than focusing on individual sub-systems. In this paper we use industry standard benchmarks and a wind-tunnel to profile typical enterprise IT. We analyze the effect of environmental conditions on IT efficiency, showing minor increases in temperature or pressure impact the efficiency of servers. Using an idealized, simulated data center case study we show that the interaction between cooling systems, server behaviour and local climate are non-trivial and increasing temperatures has potential to worsen efficiency
Assessment of the feasibility of an ultra-low power, wireless digital patch for the continuous ambulatory monitoring of vital signs.
BACKGROUND AND OBJECTIVES: Vital signs are usually recorded at 4–8 h intervals in hospital patients, and deterioration between measurements can have serious consequences. The primary study objective was to assess agreement between a new ultra-low power, wireless and wearable surveillance system for continuous ambulatory monitoring of vital signs and a widely used clinical vital signs monitor. The secondary objective was to examine the system's ability to automatically identify and reject invalid physiological data. SETTING: Single hospital centre. PARTICIPANTS: Heart and respiratory rate were recorded over 2 h in 20 patients undergoing elective surgery and a second group of 41 patients with comorbid conditions, in the general ward. OUTCOME MEASURES: Primary outcome measures were limits of agreement and bias. The secondary outcome measure was proportion of data rejected. RESULTS: The digital patch provided reliable heart rate values in the majority of patients (about 80%) with normal sinus rhythm, and in the presence of abnormal ECG recordings (excluding aperiodic arrhythmias such as atrial fibrillation). The mean difference between systems was less than ±1 bpm in all patient groups studied. Although respiratory data were more frequently rejected as invalid because of the high sensitivity of impedance pneumography to motion artefacts, valid rates were reported for 50% of recordings with a mean difference of less than ±1 brpm compared with the bedside monitor. Correlation between systems was statistically significant (p<0.0001) for heart and respiratory rate, apart from respiratory rate in patients with atrial fibrillation (p=0.02). CONCLUSIONS: Overall agreement between digital patch and clinical monitor was satisfactory, as was the efficacy of the system for automatic rejection of invalid data. Wireless monitoring technologies, such as the one tested, may offer clinical value when implemented as part of wider hospital systems that integrate and support existing clinical protocols and workflows
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