2,793 research outputs found
Bose-Einstein condensation in random directed networks
We consider the phenomenon of Bose-Einstein condensation in a random growing directed net-
work. The network grows by the addition of vertices and edges. At each time step the network
gains a vertex with probabilty p and an edge with probability 1 − p. The new vertex has a fitness
(a, b) with probability f(a, b). A vertex with fitness (a, b), in-degree i and out-degree j gains a new incoming edge with rate a(i + 1) and an outgoing edge with rate b(j + 1). The Bose-Einstein condensation occurs as a function of fitness distribution f(a, b)
Frontline Managers\u27 Perceptions and Lived Experiences in the Execution of Diversity Management Programs
For over 30 years, organizations have engaged in programs to address the growing presence of diverse populations in their ranks, and researchers have attempted to identify and quantify a link between diversity and enterprise performance. The problem was a lack of understanding of how organizations benefit from increased diversity and the role of frontline managers in that process. The purpose of this phenomenological study was to address the research question aimed at the perceptions and lived experiences of frontline managers and to gain insights about how they are navigating the challenges of increased diversity to enhance their ability to produce high-performance outcomes. The three conceptual frames used were (a) diversity management, (b) managing people, and (c) team performance. The data collection process involved interviewing 12 frontline managers from a variety of industry sectors using a semistructured, conversational interviewing protocol. The open hand-coded analysis revealed patterns of thought and behaviors relating to managing individuals, managing the complexity of diversity, and managing diverse teams for high performance. The original concept of diversity management was in response to the growing diversity in the workplace and was intended to develop the capacity among managers to manage the resulting diversity mix. The study findings indicated that a common definition of diversity management is possible, that managing diversity requires a competence with all dimensions of diversity, and that there are a set of management skills that can yield better performance with teams of diverse composition. The results of my study can have positive impact on theory, practice, and general social acceptance of diversity
Two-photon laser-induced fluorescence detection of OH
The TP-LIF OH sensor is based on the principle that a molecule having multiple energy states, all of which are bonding, can be pumped into the highest state with the resulting fluorescence being blue-shifted relative to all pumping wavelengths. In this way, one can successfully discriminate against virtually all noise sources in the system using long wavelength blocking filters in conjunction with solar-blind photomultiplier tubes. Thus, these systems tend to be signal limited rather than signal-to-noise limited as is true of the SP-LIF technique as well as other conventional analytical methods. The trick to achieving the above sampling scheme, with high efficiency, is in the use of high photon fluxes of short time duration. Obviously, the latter type of light source is fulfilled nicely by available pulsed lasers. From an operational point of view, however, this laser source needs to be tunable. The latter characteristic permits extremely high selectivity for the detection of a diatomic or simple polyatomic molecule by taking advantage of the high-resolution spectroscopic features of these type species
A non extensive approach for DNA breaking by ionizing radiation
Tsallis entropy and a maximum entropy principle allows to reproduce experimental data of DNA double strand breaking by electron and neutron radiation. Analytic results for the probability of finding a DNA segment of length l are obtained reproducing quite well the fragment distribution function experimentally obtained
Transport on complex networks: Flow, jamming and optimization
Many transport processes on networks depend crucially on the underlying network geometry, although the exact relationship between the structure of the network and the properties of transport processes remain elusive. In this paper we address this question by using numerical models in which both structure and dynamics are controlled systematically. We consider the traffic of information packets that include driving, searching and queuing. We present the results of extensive simulations on two classes of networks; a correlated cyclic scale-free network and an uncorrelated homogeneous weakly clustered network. By measuring different dynamical variables in the free flow regime we show how the global statistical properties of the transport are related to the temporal fluctuations at individual nodes (the traffic noise) and the links (the traffic flow). We then demonstrate that these two network classes appear as representative topologies for optimal traffic flow in the regimes of low density and high density traffic, respectively. We also determine statistical indicators of the pre-jamming regime on different network geometries and discuss the role of queuing and dynamical betweenness for the traffic congestion. The transition to the jammed traffic regime at a critical posting rate on different network topologies is studied as a phase transition with an appropriate order parameter. We also address several open theoretical problems related to the network dynamics
Processing plant location studies II: Policy alternatives for New Zealand wool selling centres
The nature of the general facility location problem has been discussed previously by McCarthy, Rodgers & Higham and a method of solution outlined. The present paper aims to extend the solution technique so that a number of low cost solutions with differing spatial characteristics are generated. This permits entrepreneurs or policy makers to choose among the alternatives.
The facility location problem can be stated as the determination of the number, size and location of a certain type of facility in order to satisfy the demand for the services provided; the "goodness" of any solution, relative to others, is measured in terms of some effectiveness criterion. For example one problem reported extensively in the agricultural economics literature is the determination of the number, size and location of agricultural commodity processing plants (freezing works, wool selling centres, grain storage depots), so that the sum of total transport (assembly plus distribution) costs and total processing costs are minimised.
Another general type of problem receiving attention in applied operations research relates to the number, size and location of public emergency services (for example ambulance and hospital services). Here, some measure of cost effectiveness is optimised Empirical studies include those of Fitzsimmons, Savas and Volz.
This paper is concerned primarily with processing and has two major sections. The first section outlines methodology and discusses Monte Carlo and "forcing" extensions of standard solutions. The second section applies such procedures to the New Zealand wool selling centres' location problem
Estimated validity and reliability of on-board diagnostics for older vehicles: comparison with remote sensing observations
Based on requirements under the Clean Air Act Amendments of 1990, most state vehicle inspection and maintenance (I/M) programs have, since 2002, replaced the tailpipe emission testing with the on-board diagnostic (OBD) II testing for 1996 model and newer vehicles. This test relies on the OBD II system to give the pass or fail result, depending on certain conditions that might cause the vehicle to emit pollution 1.5 times higher than the regulated standard. The OBD II system is a computer and sensors installed in the vehicle to monitor the emission control units and signal if there is any malfunction. As a vehicle ages, its engine, pollution control units, and OBD II system deteriorate. Because the OBD II system's durability directly influences the test outcome, it is important to examine the fleetwide trend in the OBD II test results in comparison with an alternative measure of identifying high emitting vehicles. This study investigates whether the validity and reliability of the OBD II test is related to the age of the OBD II system installed in the fleet. Using Atlanta's I/M testing records and remote sensing device (RSD) data collected during 2002-2005, this research establishes the convergent validity and interobserver reliability criteria for the OBD II test based on on-road emissions measured by RSDs. The study results show that older vehicles exhibit significantly lower RSD-OBD II outcome agreement than newer vehicles. This suggests that the validity and reliability of the OBD II test may decline in the older vehicle fleets. Explanations and possible confounding factors for these findings are discussed
On high moments of strongly diluted large Wigner random matrices
We consider a dilute version of the Wigner ensemble of nxn random matrices
and study the asymptotic behavior of their moments in the limit of
infinite , and , where is the dilution parameter. We show
that in the asymptotic regime of the strong dilution, the moments with
depend on the second and the fourth moments of the random entries
and do not depend on other even moments of . This fact can be
regarded as an evidence of a new type of the universal behavior of the local
eigenvalue distribution of strongly dilute random matrices at the border of the
limiting spectrum. As a by-product of the proof, we describe a new kind of
Catalan-type numbers related with the tree-type walks.Comment: 43 pages (version four: misprints corrected, discussion added, other
minor modifications
Assessment and Mitigation of Nutrients Losses from Forest Harvesting on Upland Blanket Peat - A Case Study in the Burrishoole Catchment
A survey about postoperative delirium in older patients among nurses and anaesthetists:Implications for future practice and policy
Background Postoperative delirium is a major complication associated with anaesthesia and surgery, more commonly seen in older people. Aims The aims of this study were to explore the knowledge and understanding of anaesthetists and nurses involved in anaesthesia through their responses to two case scenarios of postoperative delirium experienced by older people. Methods A 30-item online survey was sent to 500 potential respondents. Results Two hundred and twenty-six practitioners from Australia, New Zealand and Scotland responded. Most had no workplace protocols for anaesthesia planning in older people. There was substantial variability in practice in relation to postoperative delirium screening, detection, prevention and management. Conclusions Improvements in education and awareness, together with a more coherent approach, for example, as recommended in the European Society of Anaesthesiology Guidelines, could help to reduce the impact of postoperative delirium in older people. This should be combined with ongoing research into perioperative optimisation of detection, prevention and management of postoperative delirium
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