Assessment of the environmental toxicity and carcinogenicity of tungsten-based shot.

The toxicity of elemental tungsten released from discharged shot was assessed against previous studies that established a 1% toxic threshold for soil organisms. Extremely heavy theoretical shot loadings of 69,000 shot/ha were used to generate estimated environmental concentrations (EEC) for two brands of tungsten-based shot containing 51% and 95% tungsten. The corresponding tungsten EEC values were 6.5–13.5 mg W/kg soil, far below the 1% toxic threshold. The same shot loading in water produced tungsten EEC values of 2.1–4.4 mg W/L, levels that are not toxic under experimental conditions. Pure tungsten has not been shown to exhibit carcinogenic properties when ingested or embedded in animal tissues, but nickel, with which it is often alloyed, has known carcinogenicity. Given the large number of waterfowl that carry shot embedded in their body, it is advisable to screen lead shot substitutes for their carcinogenic potential through intra-muscular implantation

Follow the Leader: Adoption Behavior in Food Retailers' Decision to Offer Fresh Irradiated Ground Beef

During the 14-month period from May 2002 to June 2003, approximately 10 percent of U.S. supermarkets began to offer fresh irradiated ground beef under the stores' own labels. Using a survey of supermarket store managers from this time period, this paper investigates the factors that influenced new product offerings and adoptions. Results from the adoption model show that factors associated with competition and structure in the food retailing industry play a strong role in the decision. Among other results, we find that variables relating to a competitor's adoption status and proximity significantly affect a store's decision to offer fresh irradiated ground beef.Marketing,

Adoption Behavior in Food Retailers' Decision to Offer Fresh Irradiated Ground Beef

During the 14-month period from May 2002 to June 2003, approximately 10 percent of U.S. supermarkets began to offer fresh irradiated ground beef under the stores' own labels. Using a survey of supermarket store managers from this time period, this paper investigates the factors that influenced stores' adoption of irradiated ground beef. Results from the adoption model show that factors associated with competition, merchandising philosophy, and structure in the food retailing industry play a strong role in the decision. Among other results, we find that variables relating to a competitor's adoption status and proximity can increase the likelihood of a store's adoption decision.Marketing,

Effect of conductive cooling pads on heat and moisture production of gilts in hot and thermoneutral environments

Swine productivity, reproductivity, and well-being are reduced during periods of high temperature and the most commonly used cooling method, evaporative cooling, is not very effective under high humidity conditions. Conductive cooling pads made from pipes with cool water passing through them have the potential to cool swine under both high temperature and high humidity conditions. A study was conducted to determine some responses of gilts to conductive cooling pads under heat stress conditions. Conductive cooling pads 15 cm wide by 127 cm long were made from 13 mm diameter copper pipe and were fastened to the slatted flooring of a standard sow stall. The size and placement of the pads was such that the gilts could lie on them completely, lie on them partially, or avoid contact with them. Cool water (18⁰C) was pumped through one of the pads at a flow rate of 4 L min-1 for the treatment gilts and the control gilts had no water flowing though the cool pads. Each gilt was acclimated to thermoneutral conditions (16⁰C), and then placed in the stall in a convective indirect calorimeter under heat stress conditions (35⁰C). The animal’s total heat production, respiration rate, and moisture production were determined. Results show that during the heat stress periods, the conductive cooling pads reduced the gilt’s heat production by around 10%, moisture production by 34%, and respiration rate by 22%. In most cases, the cool pads significantly reduced the onset of panting

Different hydrogen-bonded chains in the crystal structures of three alkyl N-[(E )-1-(2-benzylidene-1-methylhydrazinyl)-3- hydroxy-1-oxopropan-2-yl]carbamates

Peer reviewedPublisher PD

Emergent Universe from A Composition of Matter, Exotic Matter and Dark Energy

A specific class of flat Emergent Universe (EU) is considered and its viability is tested in view of the recent observations. Model parameters are constrained from Stern data for Hubble Parameter and Redshift ($H(z)$ vs. $z$) and from a model independent measurement of BAO peak parameter. It is noted that a composition of Exotic matter, dust and dark energy, capable of producing an EU, can not be ruled out with present data. Evolution of other relevant cosmological parameters, viz. density parameter ($\Omega$), effective equation of state (EOS) parameter ($\omega_{eff}$) are also shown.Comment: 5 pages, 5 figures (accepted in MNRAS

Towards automated design of quantum cascade lasers

We present an advanced technique for the design and optimization of GaAs/AlGaAs quantum cascade laser structures. It is based on the implementation of the simulated annealing algorithm with the purpose of determining a set of design parameters that satisfy predefined conditions, leading to an enhancement of the device output characteristics. Two important design aspects have been addressed: improved thermal behavior, achieved by the use of higher conduction band offset materials, and a more efficient extraction mechanism, realized via a ladder of three lower laser states, with subsequent pairs separated by the optical phonon energy. A detailed analysis of performance of the obtained structures is carried out within a full self-consistent rate equations model of the carrier dynamics. The latter uses wave functions calculated by the transfer matrix method, and evaluates all relevant carrier–phonon and carrier–carrier scattering rates from each quantized state to all others within the same and neighboring periods of the cascade. These values are then used to form a set of rate equations for the carrier density in each state, enabling further calculation of the current density and gain as a function of the applied field and temperature. This paper addresses the application of the described procedure to the design of lambda~9 µm GaAs-based mid-infrared quantum cascade lasers and presents the output characteristics of some of the designed optimized structures. © 2005 American Institute of Physic