Biochemical‐genetic variation in a wild and a cultured population of the greenshell mussel,Perna canaliculus

A wild and a cultured greenshell mussel (Perna canaliculus) population were compared for biochemical genetic variation at seven polymorphic and four monomorphic allozyme loci. Significant heterozygote deficiencies were observed for all polymorphic loci (La—1, La—2, Lap, Lgg—1, Lgg— 2, Pgi, and Pgm) for both populations (except the Pgi locus of the wild mussel population). Genotypic disequilibrium was calculated for both populations: genotypic frequencies were significantly non‐random at three pairs of loci among the wild mussels, and significantly non‐random at three different pairs of loci among the cultured mussels. All six pairs of loci which exhibited significant genotypic disequilibrium involved amino‐peptidases, suggesting that these loci form a linkage group, and that neither the Pgi nor the Pgm loci are associated with this group. Exact tests for population differentiation based upon population‐specific allele distributions indicated that four of the polymorphic loci were significantly heterogeneous among the two populations, whereas the remaining three polymorphic loci were not. Based upon the private allele system, the number of migrants (N _m) between the populations was estimated to be 2.009, which, according to the private allele system, represents a high level of gene flow. These findings are discussed with regard to the population biology and genetic structure of this species.     

Lamprey (Geotria australis; Agnatha) reddening syndrome in Southland rivers,New Zealand 2011–2013: laboratory findings and epidemiology,including the incidental detection of an atypical Aeromonas salmonicida

From 2011, lamprey (Geotria australis) populations in Southland, New Zealand have been affected by reddening along the length of the body and increased mortalities, termed lamprey reddening syndrome (LRS). Molecular testing, bacteriology, histopathology and epidemiology were used to determine if an infectious agent was present and to increase the understanding of this syndrome. An atypical Aeromonas salmonicida was detected from affected lamprey in 2011. This organism has not previously been reported from New Zealand. Investigative molecular testing indicated the organism was an uncharacterised, unculturable, atypical A. salmonicida and a likely incidental finding. Histopathology did not indicate an infectious process was involved, but suggested the reddening may be due to blunt trauma. Epidemiological investigation found the Mokoreta River had a significantly higher prevalence of LRS than others in the Southland region, but there was no clear reason why. To date, no infectious aetiology for this syndrome has been identified.     

The dependence of facula-photosphere contrast in molecular lines on dissociation energy

Assuming local thermodynamic equilibrium and the same relative abundances to prevail both in photosphere and faculae, the concentration-optical depth curves for molecules CH, NH, OH, C₂, CN and CO have been obtained for the four combinations of two photospheric and two facular models and the relative excesses of these molecules in the photosphere over those in faculae have been calculated. The change of photospheric model significantly affects the relationship, for a given facular model, between and D ₀, the dissociation energy of the molecule concerned. Besides, the average depth of formation in the facular models and photospheric models shows a relationship with D ₀.     

Irrotational motion in quiescent prominences

On the basis of Kippenhahn and Schlüter's magnetohydrostatic model of a quiescent prominence, an attempt has been made to study the effect of irrotational motion existing in the prominences on the magnetic field pattern in it, introducing an irrotational velocity field. It is found that, under such a condition, the magnetic field geometry in the model does not change.     

Linking Coastal Disasters and Migration: A Case Study of Kutubdia Island,Bangladesh

On 4 August 2012, the southeastern part of Kutubdia Island, Bangladesh, experienced coastal erosion and flooding associated with tidal waves, storms, and continuous heavy rainfall for two days. This provided a unique opportunity to study the relationship between rapid-onset disasters and migration decisions of individual households perpetually living under environmental risk. Using Kutubdia Island as a case study, this article examines the migration decisions of respondents in the immediate aftermath of two extreme natural events. Relevant data were primarily collected from a questionnaire survey conducted nearly two months after the occurrence of the event. The study's findings support the view that both environmental and nonenvironmental factors lead to migration. The article outlines several areas for further research on the links between migration and environmental stress.     

Factors Affecting Evacuation Behavior: The Case of 2007 Cyclone Sidr,Bangladesh

Cyclone Sidr, a Category 4 storm, struck the southwestern coast of Bangladesh on 15 November 2007. Despite early cyclone warnings and emergency evacuation orders for coastal residents, thousands of individuals stayed in their homes. This study examines Sidr victims’ responses to cyclone warnings and evacuation orders, and explores the factors that would explain why the victims did or did not comply with the orders. Based on survey data collected from 277 Sidr survivors living in the four most severely impacted coastal districts, this study found that more than 75 percent of all respondents were aware of the cyclone warnings and evacuation orders before Sidr's landfall. Despite the efforts of the Bangladesh government, there were lapses in cyclone warnings and evacuation procedures. Field data also reveal several reasons cited by respondents for not complying with evacuation orders. Multivariate analyses of survey data show that trust in warning messages was the most important determinant in the decision to seek refuge in safer shelters, followed by distance to nearest shelter and annual level of education. Several recommendations have been made to improve cyclone warnings and the use of public shelters for similar future events.     

LOCAL SCOUR AROUND BRIDGE ABUTMENTS

1 INTRODUCTION The protrusion of a bridge abutment or a spur dike into the main channel creates a disturbance and obstruction to the otherwise equilibrium state of sediment transportation in an alluvial river. The flow accelerates and separates at the upstream face of the abutment as it moves past the obstacle, creating a vortex trail that moves downstream in a direction approximately perpendicular to the structure. The result is that the bed around the structure is eroded locally. The l…     

The assessment of potential land use in the proposed irrigation command using Remote Sensing and GIS

Standard false colour composites (Std. FCC) on 1:50,000 scale was visually interpreted in conjunction with soil survey to prepare physiographic-soil map. Thirteen mapping units were delineated indicating soil association at family-level. Soil and land resource was evaluated for their land capability and irrigation suitability for its sustained use under irrigation. Land capability and land irrigability maps were generated as attribute map. These maps were integrated to suggest potential land use map. Current land use/land cover map prepared by visual analysis was spatially analysed in relation to potential land use to study potential changes in land use / land cover using GIS. The study reveals that 14.66% area has no limitation and can be brought to intensive agriculture by double cropping.     

Soil-Physiography relationship in Mahanadi Delta (Part) using Landsat Imagery

Visual Interpretation of Landsat Imagery (TM-FCC) on 1∶250,000 scale covering 2410 sq km in a part of Mahandi Delta, Kataka district, Orissa was carried out for delineating the physiographic units. The major physiographic units identified and delineated were ‘Delta plain’ and ‘Coastal plain’. These units were further subdivided on the basis of image elements. The abstraction level attained was ‘Family’ based on Soil Taxonomy. The soils of the beach were classified as Typic Ustipsamments; old coastal plain as fine, Typic Haplaquept and coarse loamy Aquic Ustifluvent; Tidal flat as fine Typic Haplaquept and fine loamy Aquic Ustifluvent; mud flat as fine Typic Haplaquept; Levee-plain complex as Typic Ustipsamment and fine loamy Typic Ustorthent; old Delta plain as fine Udic Ustochrept and Aeric Haplaquept and recent delta plain as fine loamy and coarse loamy Typic Ustorthent. The soils are mixed in mineralogy and Isohyperthermic in temperature regime.