The modelling of soil plasticity

The modeling of the soil plasticity was discussed and it was shown that the grain breakage is an important factor of the plastic soil behaviour. A reduction of internal coefficient of friction was observed when stress-level was increased. The yield paths of all stress path tests determined by curve fitting were presented.

Discrete dislocation plasticity analysis of crack-tip fields in polycrystalline materials

Small scale yielding around a mode I crack is analysed using polycrystalline discrete dislocation plasticity. Plane strain analyses are carried out with the dislocations all of edge character and modelled as line singularities in a linear elastic material. The lattice resistance to dislocation motion, nucleation, interaction with obstacles and annihilation are incorporated through a set of constitutive rules. Grain boundaries are modelled as impenetrable to dislocations. The polycrystalline material is taken to consist of two types of square grains, one of which has a bcc-like orientation and the other an fcc-like orientation. For both orientations there are three active slip systems. Alternating rows, alternating columns and a checker-board-like arrangement of the grains is used to construct the polycrystalline materials. Consistent with the increasing yield strength of the polycrystalline material with decreasing grain size, the calculations predict a decrease in both the plastic zone size and the crack-tip opening displacement for a given applied mode I stress intensity factor. Furthermore, slip-band and kink-band formation is inhibited by all grain arrangements and, with decreasing grain size, the stress and strain distributions more closely resemble the HRR fields with the crack-tip opening approximately inversely proportional to the yield strength of the polycrystalline materials. The calculations predict a reduction in fracture toughness with decreasing grain size associated with the grain boundaries acting as effective barriers to dislocation motion.

Cross-species chromosome painting in the Perissodactyla: delimitation of homologous regions in Burchell's zebra (Equus burchellii) and the white (Ceratotherium simum) and black rhinoceros (Diceros bicornis)

Conserved chromosomal segments in the black rhinoceros, Diceros bicornis (DB1, 2n = 84), and its African sister-species the white rhinoceros, Ceratotherim simum (CSI, 2n = 82), were detected using Burchell's zebra (Equus burchellii, EBU, 2n = 44) chromosome-specific painting probes supplemented by a subset of those developed for the horse (Equus caballus, ECA, 2n = 64). In total 41 and 42 conserved autosomal segments were identified in C simum and D. bicornis respectively. Only 21 rearrangements (20 fissions and I fusion) are necessary to convert the Burchell's zebra karyotype into that of the white rhinoceros. One fission distinguishes the D. bicornis and C simum karyotypes which, excluding hetero- chromatic differences, are identical in all respects at this level of resolution. Most Burchell's zebra chromosomes correspond to two rhinoceros chromosomes although in four instances (EBU 18, 19, 20 and 21) whole chromosome synteny has been retained among these species. In contrast, one rhinoceros chromosome (DBI1, CSI1) comprises two separate Burchell's zebra chromosomes (EBU11 and EBU17). In spite of the high diploid numbers of the two rhinoceros species their karyotypes are surprisingly conserved offering a glimpse of the putative ancestral perissodactyl condition and a broader understanding of genome organization in mammals. Copyright (C) 2003 S. Karger AG, Base

Contrast features of CpG islands in the promoter and other regions in the dog genome

The recent release of the domestic dog genome provides us with an ideal opportunity to investigate dog-specific genomic features. In this study, we performed a systematic analysis of CpG islands (CGIs), which are often considered gene markers, in the dog

CpG islands or CpG clusters: how to identify functional GC-rich regions in a genome?

Background: CpG islands (CGIs), clusters of CpG dinucleotides in GC-rich regions, are often located in the 5' end of genes and considered gene markers. Hackenberg et al. ( 2006) recently developed a new algorithm, CpGcluster, which uses a completely diffe

Comparison of Pax1/9 locus reveals 500-Myr-old syntenic block and evolutionary conserved noncoding regions

Identification of conserved genomic regions within and between different genomes is crucial when studying genome evolution. Here, we described regions of strong synteny conservation between vertebrate deuterostomes (tetrapods and teleosts) and invertebrat

Water quality parameters of coastal shrimp farms from southwest and southeast regions of Bangladesh

The impacts of shrimp farming on water quality and effluent loading of shrimp farms in southwest (Khulna) and southeast (Cox's Bazar) regions of Bangladesh was investigated during March-August and August-October season, respectively. Water salinity fluctuated from 3.0 to 15.0 ppt in the southwest, whereas it was between 2.5 to 20.0 ppt. in southeast region. Total ammonia nitrogen as recorded in most farms of Cox's Bazar region was higher (0. 1160.438 mg/L) than the recommended level of shrimp farming. Mean values of total ammonia nitrogen and total nitrogen at the outlet of shrimp farms were higher than those of inlet in both regions. Mean values of phosphate phosphorus and total phosphorus at outlet were lower than inlet except in harvest time of Penaeus monodon. Total suspended solids were deposited on the bottom of shrimp farms in both regions, which resulted in higher concentration in inlets than outlets in both regions.

Some biochemical constituents and the calorific values of different regions of the body musculature of pond murrel Channa punctatus Bloch

A study of the distribution of some chemical constituents in the musculature of Channa punctatus Bloch showed it to be fairly heterogeneous. The increase in the levels of protein, fat, ash, total carbohydrates, glycogen, RNA, DNA and cholesterol towards the posterior region of the fillet was the result of increase in the number of cells per unit weight of the sample and in the concentration of myocommata. The distribution of water in the musculature was inversely related to that of the fat. The concentration of protein appeared to be associated with the RNA level. The posterior region of the fillet exhibited more calorific value than the anterior region.

Phylogenetic relationships of Drosophila melanogaster species group deduced from spacer regions of histone gene H2A-H2B

Nucleotide sequences of the spacer region of the histone gene H2A-H2B from 36 species of Drosophila melanogaster species group were determined. The phylogenetic trees were reconstructed with maximum parsimony, maximum likelihood, and Bayesian methods by u

A framework for analysing business performance, firm innovation and related contextual factors: Perceptions of managers and policy makers in two European regions

The aim of this paper is to propose a novel reference framework that can be used to study how different kinds of innovation can result in better business performance and how external factors can influence both the firm's capacity to innovate and innovation itself. The value of the framework is demonstrated as it is applied in an exploratory study of the perceptions of public policy makers and managers from two European regions - the Veneto Region in Italy and the East of England in the UK. Amongst other things, the data gathered suggest that managers are generally less convinced than public policy makers, that the innovativeness of a firm is affected by factors over which policy makers have some control. This finding poses the question "what, if any, role can public policy makers play in enhancing a company's competitiveness by enabling it to become more innovative?".

Secondary structural analysis of the mRNA regions encoding the hemagglutinin cleavage site basic amino acids of the avian influenza virus H5N1 subtype samples

Here we report the codon bias and the mRNA secondary structural features of the hemagglutinin (HA) cleavage site basic amino acid regions of avian influenza virus H5N1 subtypes. We have developed a dynamic extended folding strategy to predict RNA secondar

Culture potential of Amblypharyngodon mola with carps in polyculture in farmers' pond of northern regions of Bangladesh

To assess the culture potential of mola (Amblypharyngodon mola) along with carps in polyculture systems, an experiment consisted of three treatments each with five replications was conducted for 4 months in two villages of Parbatipur upazilla under Dinajpur district. In the first treatment (SS), catla, rohu, mrigal, grass carp, Thai punti, common carp and a higher density of silver carp (8 per 40m²) were stocked. In the second treatment (SM), stocking density of silver carp was reduced to half and mola was added at a stocking density of 12,500/ha with all other fishes used in SS. In the third treatment (MM), no silver carp was stocked and mola was added at a stocking density of 25,000/ha with all other fishes used in SS. All treatments were subjected to the same regime of feed and fertilizers. The yields of large carps were 2035 kg/ha, 1757 kg/ha and 1326 kg/ha for treatments SS, SM and MM, respectively. Catla, grass carp and carpio showed better growth and production performance in presence of mola at a higher density, while rohu, Thai punti and mrigal showed better performance when stocking density of mola was relatively low. Mola yield was almost two times higher (184 kg/ha) in absence of silver carp (MM) than (62 kg/ha) in presence of silver carp (SM). The result showed that there was a significantly (p<0.01) lower total fish production in treatment MM. But there were no significant difference in total production between treatment SS and SM.