On Source Density Evolution of Gamma-ray Bursts

Recent optical afterglow observations of gamma-ray bursts indicate a setting and distance scale that many relate to star-formation regions. In this paper, we use $$ and a set of artificial trigger thresholds to probe several potential GRB source density evolutionary scenarios. In particular, we compare a uniform subset of BATSE 4B data to cosmological scenarios where GRBs evolve as the comoving density, the star formation rate, the QSO rate, and the SN Type Ic rate. Standard candle bursts with power-law spectra and a universe without vacuum energy were assumed. Our results significantly favor a comoving density model, implying that GRB source density evolution is weaker than expected in these evolutionary scenarios. GRB density might still follow star-formation rates given proper concurrent GRB luminosity evolution, significant beaming, significant error in standard candle assumptions, or were a significant modification of star formation rate estimates to occur.Comment: 12 pages, 4 figures, accepted by Ap

Fisheries Instrument Choice under Uncertainty

This paper uses data from an actual fishery to construct a tractable and dynamic model to compare expected profit and its variance, optimal stock size, optimal harvest rate and optimal fishing effort under different management regimes under uncertainty. The results provide a comparison of instrument choice between a total harvests control and a total effort control under uncertainty, an original method to evaluate the tradeoffs between profits and other criteria in a dynamic context, and provide guidance as to the relative merits of catch and effort controls in fisheries management.fisheries management, uncertainty

The mediation between participative leadership and employee exploratory innovation: Examining intermediate knowledge mechanisms

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.We examine mediation effects of coworker knowledge sharing and absorptive capacity on the participative leadership–employee exploratory innovation relationship in R&D units of Taiwanese technology firms. Deploying a time-lagged questionnaire method implemented over four business quarters, data is generated from 1600 paired samples (managers and employees) in R&D units of Taiwanese technology firms. The structural equation modeling results reveal that (1) participative leadership is positively related to employee exploratory innovation; (2) coworker knowledge and (3) absorptive capacity partially mediate the relationship between participative leadership and employee exploratory innovation independently; and, (4) coworker knowledge sharing in combination with absorptive capacity partially mediates this relationship. The results extend previous research on participative leadership and innovation by demonstrating that participative leadership is related to employee exploratory innovation (Lee and Meyer-Doyle, 2017; Mom et al., 2009).Results also confirm that participative leadership drives employee exploratory innovation through employee absorptive capacity. This reinforces the need highlighted by Lane et al. (2006) to investigate the role of absorptive capacity at the individual-level. Collectively, while participative leadership is important for employee exploratory innovation it is the knowledge mechanisms existing and interacting at the employee-level that are central to generating increased employee exploratory innovation from this leadership approach

Carbon nanomaterials as drug transporter for cancer therapy

There is a vigorous and growing research effort developing carbon nanotubes (CNTs) for medical applications. It is now known that nanocomposites of Single Wall Nanotubes (SWNTs) can be used to deliver anti-cancer drugs to cells. Also, SWNTs are efficient at converting near infrared (NIR) light to heat, and can do so in a cell, and so cancer cells can be targeted for destruction by NIR radiation, once the cells have taken up SWNTs. SWNTs are highly insoluble in water, but can be functionalized via physical or covalent attachment of solubilizing molecules and drugs of interest. Once this is done, they are readily taken up by cells. We found evidence that our CNT nanocomposites were found to enter cells via endocytosis (the mechanism cells use to take up nutrients); this agrees with earlier work by Dai and coworkers. Herein, we perform systematic study of the internalization, delivery and subcellular localization and possible adverse effects of SWNTs dispersed in culture media and SWNTs wrapped with different fluorescently labelled peptide (FLP-SWNTs) on Chinese hamster ovary (CHO) cells and SWNTs attached with anti-cancer drug on two common cancerous cell lines, human epithelial carcinoma cell line (HeLa) and colorectal cancer cell lines (WiDr)

Capacity Reduction and Productivity: The Case of Fishery

The paper presents the first ex-post analysis of profit and productivity of individual vessels following a vessel or licence buyback in a fishery. Using individual firm-level data for the period 1997-2000, the paper analyzes a "natural experiment" of the effects of a 1997 scheme to reduce fishing capacity in the South East trawl fishery of Australia. The scheme was unique in the sense that the buyback was implemented in a fishery managed by individual vessel tradeable harvesting rights rather than input controls. Using an innovative index method that decomposes the contributions of output prices, input prices, vessel size and productivity to relative profits, the economic performance of vessels is analyzed in the year of the buyback and for three years afterwards. Profits for all vessel classes rose over the period 1997-2000 following the 1997 buyback of 27 fishing licenses, but some of the gains were due to a rise in output prices that were independent of the adjustment program. All vessel classes (small and large) also experienced substantial productivity gains immediately following the 1997 license buyback with an average increase over all vessels of 39%. This increase, coincident with a decline in catch per unit of effort for key species, provides strong support that the buyback was successful at improving economic performance. Ongoing productivity improvements for small vessels over the period 1998-2000 following the buyback is attributed to the existence of individual tradeable harvesting rights in the fishery.productivity, capacity reduction, fishery

Technical Efficiency Effects of Input Controls: Evidence from Australia's Banana Prawn Fishery

The paper provides the first ex-post estimates of the effects on technical efficiency of input controls in a fishery. Using individual vessel data from the northern prawn fishery of Australia for the years 1990–1996 and 1994–2000, a stochastic production frontier is estimated to analyse the efficiency impacts of input controls on engine and vessel size. The results indicate that technical efficiency is increasing in a measure of vessel size and engine capacity that was controlled by the regulator from 1985 to 2001, and decreasing in an unregulated input, gear headrope length. The study shows that fishers have substituted from regulated to unregulated inputs over the period 1990-2000 and technical efficiency has declined coincident with increasing restrictions on vessel size and engine capacity. The decline in technical efficiency indicates that the goal of the regulator to increase economic efficiency has not been realised.input controls, efficiency, fishery

Correlations among superconductivity, structural instability, and band filling in Nb1-xB2 at the critical point x=0.2

We performed an extensive investigation on the correlations among superconductivity, structural instability and band filling in Nb1-xB2 materials. Structural measurements reveal that a notable phase transformation occurs at x=0.2, corresponding to the Fermi level (EF) in the pseudogap with the minimum total density of states (DOS) as demonstrated by the first-principles calculations. Superconductivity in Nb1-xB2 generally becomes visible in the Nb-deficient materials with x=0.2. Electron energy-loss spectroscopy (EELS) measurements on B K-edge directly demonstrated the presence of a chemical shift arising from the structural transformation. Our systematical experimental results in combination with theoretical analysis suggest that the emergence of hole states in the sigma-bands plays an important role for understanding the superconductivity and structural transition in Nb1-xB2.Comment: 16 pages, 4 figure