Bangladesh Food Price Report 2012: Eating in a Time of Food Price Volatility

DFI

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

Substituting Wood with Nonwood Fibers in Papermaking: A Win-Win Solution for Bangladesh

Bangladesh is facing an acute shortage of fibrous raw materials for the production of pulp and paper. On the other hand, the demand for paper and paper products is increasing day by day. This study reviews the availability and suitability of nonwood raw materials for pulp production in Bangladesh. It shows that Bangladesh has a huge amount of unused jute fiber, which is highly suitable for papermaking in Bangladesh. Other agricultural wastes like rice straw, dhaincha, golpata fronds, cotton stalks, corn stalks, and kash are also available and may be used for some pulp production. Given the different properties of these different nonwood fibers, jute pulp can be used as a reinforcing agent with other nonwood pulps for the production of high quality paper in Bangladesh.Bangladesh, natural fibers, jute, paper making, pulp

Life in a Time of Food Price Volatility: Bangladesh Country Synthesis Report 2012-2014

DFI

A Short Review on the Development of Salt Tolerant Cultivars in Rice

Rice is staple food for half of the world. With a population of almost 9.6 billion by the year 2050, there is a dire need of developing techniques to improve the crop plants, not only in terms of better yield but also to withstand harsh environmental conditions and stresses like drought, temperature, flood and salinity. Salinity is second to drought stress and hence it is very important to develop crops tolerant to salinity stress. This review discusses the mechanisms of salt tolerance and the recent developments in understanding the complex tolerance phenomena. One way to address the salinity issue is to develop tolerant rice varieties using conventional and modern breeding techniques for which screening the rice germplasm for the varieties with desired traits is critical. Conventional methods to develop tolerant rice varieties are discussed along with modern biotechnology techniques are also discussed. Quantitative Trait Loci (QTL) and Marker Assisted Selection (MAS) are promising techniques. In addition to these modern techniques, some recent developments in the fields of transgenic plants, haploid breeding and Somaclonal variations have also been discussed. The limited knowledge about molecular and genetic mechanisms to tolerate abiotic stresses, however is a barrier to efficiently develop tolerant cultivars. A combination of conventional and modern biotechnology techniques could possibly open up the new ways

Evaluation of growth of Chlorella ellipsoidea in different culture media

An experiment was conducted to evaluate the growth of Chlorella ellipsoidea in three different media viz,. medium I (pulse bran), medium II (soil extract) and medium III (inorganic) under the natural environmental conditions. The alga, C. ellipsoidea, reached maximum cell density of 56.32 × 106 cells ml-1 in 10 days in medium I (pulse bran), maximum cell density of 102.99 × 106 cells ml-1 in 11 days in medium II (soil extract) and maximum cell density of 64.23 × 106 cells ml-1 in 12 days in medium III (inorganic medium). The ranges of water temperature, air temperature and light intensity were 22 to 32ºC, 22 to 34ºC and 2.11 to 4.31 (× 103) lux, respectively during the culture period. The average sunshine period was 7.65 ± 1.57 hours. Total alkalinity, free CO2, pH, NO3-N, PO4- P of algal culture medium I, medium II and medium III were 220, 200 and 150 mg L-1 ; 26, 9 and 19 mg L-1; 7.9, 7.6 and 7.5; 45, 45 and 133.33 mg L-1; 10.9, 15.1 and 37.06 mg L-1, respectively. Cell densities of cultures of C. ellipsoidea under three treatments I, II and III, it can be concluded that cell densities under 3 treatments are significantly different (F=39.78) and treatment II (soil extract medium) is the best for algal (C. ellipsoidea) culture among three treatments. DOI: http://dx.doi.org/10.3329/ijarit.v4i2.22636 Int. J. Agril. Res. Innov. & Tech. 4 (2): 6-10, December, 201

piRNAs and Aubergine cooperate with Wispy poly(A) polymerase to stabilize mRNAs in the germ plasm

Piwi-interacting RNAs (piRNAs) and PIWI proteins play a crucial role in germ cells by repressing transposable elements and regulating gene expression. In Drosophila, maternal piRNAs are loaded into the embryo mostly bound to the PIWI protein Aubergine (Aub). Aub targets maternal mRNAs through incomplete base-pairing with piRNAs and can induce their destabilization in the somatic part of the embryo. Paradoxically, these Aub-dependent unstable mRNAs encode germ cell determinants that are selectively stabilized in the germ plasm. Here we show that piRNAs and Aub actively protect germ cell mRNAs in the germ plasm. Aub directly interacts with the germline-specific poly(A) polymerase Wispy, thus leading to mRNA polyadenylation and stabilization in the germ plasm. These results reveal a role for piRNAs in mRNA stabilization and identify Aub as an interactor of Wispy for mRNA polyadenylation. They further highlight the role of Aub and piRNAs in embryonic patterning through two opposite functions

Prolonged heating of honey increases its antioxidant potential but decreases its antimicrobial activity

Background: Honey is renowned for its antioxidant, antimicrobial and medicinal properties. It is typically heated and filtered during processing to avoid crystallization. However, few studies have reported its heating effect and the antioxidant and antimicrobial activities of honey.Materials and Methods: In this study, honey samples were collected from eight different honey-producing sites in Bangladesh and heated to 50ºC, 70ºC and 90ºC for 12 hours, while the antioxidant potentials and antimicrobial properties of the heated samples were compared with those of the unheated samples. Antimicrobial properties were investigated against one Gram-positive and eight Gram-negative bacteria. Other physicochemical and biochemical properties were also determined.Results: Interestingly, there was a proportionate increase in the amount of antioxidant compounds (phenolics and flavonoids) as well as antioxidant potentials proportional with the amount of heat introduced, whereas the antimicrobial properties of the honey samples were reduced with increasing heat.Conclusion: In conclusion, though prolonged heat treatment of honey can increase its antioxidant potential, antimicrobial activities are compromised.Keywords: Honey, heat, antioxidant, antimicrobial