Overfishing Trends and the Global Food Crisis

Fish are a vital source of nourishment, especially to people in the world's poorest nations. Widespread over?shing has led to a decline in catch globally; however, the links between over?shing and food security have not been well-understood. The authors of scientific article "Food security implications of globalmarine catch losses due to overfishing." assessed potential losses, globally and regionally, in ?sheries catch and revenue resulting from over?shing. They found a third to a half of commercial marine species had been over?shed during the past half-century, with billions in potential revenue lost. By placing country-level catch loss trends in the context of undernourishment levels in many of the world's poorest countries, the authors estimated that in 2000 the additional catch from sustainable ?shing could have helped 20 million people cover their food de?cit and avert undernourishment. This Pew Ocean Science Series report is a summary of the scientists' ?ndings

Is the subharmonic threshold always lower than the fundamental one in plane Poiseuille flow.

We revisit the secondary instability of a Tollmein-Schlichting wave in plane Poiseuille flow at Re = 5000 and find that the fundamental threshold can be lower than the subharmonic one in the wavenumber space, in contrast to the prevalent view in the literature that only instability of subharmonic modes occurs at very low disturbance amplitudes and fundamental modes need a higher disturbance amplitude to become unstable. This is because of overlooking the even class of fundamental modes, which happen to produce the lower threshold at those wavenumbers. Published by AIP Publishing

Frequency Dependence of Magnetoelectric Interactions in Layered Structures of Ferromagnetic Alloys and Piezoelectric Oxides

Magnetoelectric (ME) interactions in layered structures of magnetostrictive and piezoelectric phases are mediated by mechanical deformation. Here we discuss the frequency dependence of ME coupling in bilayers and trilayers of Permendur, a ferromagnetic alloy, and lead zirconate titanate. Data on ME voltage coefficient versus frequency profiles reveal a giant ME coupling at electromechanical resonance. The maximum voltage coefficient of 90 V/cm Oe is three orders of magnitude higher than low-frequency values. The ME interactions for transverse fields is an order of magnitude stronger than for longitudinal fields. These results are in agreement with theory. The resonance ME effect, therefore, is a novel tool for enhancing the magnetic-to-electric field conversion efficiency in the composites.Comment: accepted for publication as rapid communication in Applied Physics

A Novel High-Cell-Density Protein Expression System Based on Ralstonia eutropha

We describe the development of a novel protein expression system based on the industrial fermentation organism Ralstonia eutropha (formerly known as Alcaligenes eutrophus) NCIMB 40124. This new system over- comes some of the shortcomings of traditional Escherichia coli-based protein expression systems, particularly the propensity of such systems to form inclusion bodies during high-level expression. Using a proteomics approach, we identified promoters that can be induced by simple process parameters or medium compositions in high-density cell culture or shake flasks, respectively. By combining newly developed molecular biological tools with a high-cell-density fermentation process, we were able to produce high levels (\u3e1 g/liter) of soluble, active organophosphohydrolase, a model enzyme prone to inclusion body formation in E. coli

Comparison of Measured and Predicted Performance and the Emission Characteristics of Single Cylinder CI Engine using Pongamia Pinnata based Bio-Diesel

Diesel being the main transport fuel, developing countries like India spends a lot of money to import petroleum and the use of petroleum based fuels increased in the recent years is the main contributor to the urban air pollution. Finding a suitable alternative to diesel is an urgent need. Biofuels are renewable, can supplement petroleum based fuels. Due to pressure on edible oils, non-edible oils of Pongamia Pinnata (karanja) and Jatropa Curcas are evaluated as diesel fuel extender. Pongamia pinnata based bio-diesel (PBD) is receiving increasing attention in India because of its potential to increase the rural employment and relatively low impact on environment. Diesel engines running on PBD are found to emit higher oxides of nitrogen. In this work a single cylinder constant speed water cooled four stroke direct injection diesel engine is selected for the experimental investigations to model the performance and emission characteristics fueled with plain Diesel and Pongamia Bio-diesel blends PBD10 (10% Pongamia Bio-diesel and 90% Diesel) and PBD20 (20% Pongamia Bio-diesel and 80% Diesel) with different cooled EGR rates (0%, 5%, 10%, 15% and 20%). The performance parameters are analyzed include specific fuel consumption and brake thermal efficiency whereas exhaust emissions include nitric oxide (NO), carbon monoxide (CO) and smoke opacity. The results of the experiments in each case were used to model the performance and emission parameters. Multivariate non linear regression analysis is carried out in Minitab software to model the performance and emission parameters. The predicted values were compared with experimental data

Synthesis and structure characterization of [Co(H2O)2(DMSO)2(4-nba)]4-nba (DMSO = dimethylsulfoxide; 4-nba = 4-nitrobenzoate)

51-56Dissolution of a fine powder obtained by mechanochemical grinding of cobaltous carbonate with 4-nitrobenzoic acid (4-nbaH) in hot dimethylsulfoxide (DMSO) followed by slow evaporation of the solvent resulted in the formation of cis-diaquabis(dimethylsul-foxide)4-nitrobenzoatocobalt(II) 4-nitrobenzoate 1 in good yield. The title compound [Co(H2O)2(DMSO)2(4-nba)]4-nba 1 crystallizes in the centrosymmetric monoclinic P21/c space group. The structure of 1 consists of two crystallographically independent Co(II) ions. Each unique cobalt exhibits octahedral geometry and is bonded to a pair of terminal aqua ligands situated cis to each other and a bidentate 4-nba ligand which form the square base of the octahedron. A pair of DMSO ligands disposed trans to each other complete the hexa coordination around the central metal. The [Co(H2O)2(DMSO)2 (4-nba)]+ cations and the 4-nba anions are interlinked with the aid of several weak H-bonding interactions. A comparative study of several 4-nitrobenzoate compounds of cobalt is described

Flux Expulsion - Field Evolution in Neutron Stars

Models for the evolution of magnetic fields of neutron stars are constructed, assuming the field is embedded in the proton superconducting core of the star. The rate of expulsion of the magnetic flux out of the core, or equivalently the velocity of outward motion of flux-carrying proton-vortices is determined from a solution of the Magnus equation of motion for these vortices. A force due to the pinning interaction between the proton-vortices and the neutron-superfluid vortices is also taken into account in addition to the other more conventional forces acting on the proton-vortices. Alternative models for the field evolution are considered based on the different possibilities discussed for the effective values of the various forces. The coupled spin and magnetic evolution of single pulsars as well as those processed in low-mass binary systems are computed, for each of the models. The predicted lifetimes of active pulsars, field strengths of the very old neutron stars, and distribution of the magnetic fields versus orbital periods in low-mass binary pulsars are used to test the adopted field decay models. Contrary to the earlier claims, the buoyancy is argued to be the dominant driving cause of the flux expulsion, for the single as well as the binary neutron stars. However, the pinning is also found to play a crucial role which is necessary to account for the observed low field binary and millisecond pulsars.Comment: 23 pages, + 7 figures, accepted for publication in Ap