Tree-ring reconstructions of winter climate and circulation indices for the southwestern United States

A key to understanding the causes for climate variability lies in understanding how atmospheric circulation influences regional climate. The goal of this research is to investigate the long-term relationships between atmospheric circulation and winter climate in the southwestern United States. Patterns of atmospheric circulation are described by circulation indices, and winter climate is defined as number of days with precipitation and mean maximum temperature for the winter wet season, November through March. Records of both circulation indices and climate variables were reconstructed with tree-ring chronologies for the period 1702-1983. The years of the highest and lowest values of circulation indices and climate variables were compared in order to investigate possible spatial and temporal relationships between extremes in circulation and climate.

Morphometric studies in Penaeus merguiensis from Ratnagiri waters for selection of the brood stock in genetic improvement programmes

Studies on genetic improvement of penaeid prawns for the character higher tail weight using methods of selective breeding were undertaken. Prior to the actual breeding experiments it was necessary to find out the quantum of available variability in the character tail weight amongst the natural populations of Penaeus merguiensis from the Indian waters. Thirteen morphometric variables were measured and various statistical analyses were carried out. The tail weight showed almost double values of coefficient of variation in the females than the males (C.V. 20.37 and 11.08 respectively). The combination of the characters viz. sixth segment length (SSL), sixth segment depth (SSD) and posterior abdominal circumference (PAC) gave the highest R super(2) values. These variables were easy to measure and gave maximum variation in the character tail weight without sacrificing the breeders in the brood stock. The quantitative character tail weight was influenced by both genetic and environmental factors was statistically ascertained by applying 2-Factor analysis.

Indices and fecundity of a threatened freshwater catfish Mystus montanus

Fecundity of threatened catfish Mystus montanus was estimated from a collection of gravid females, which ranged from 290 to 27,972 according to body length and weight. The relationship between fecundity and BL, BW, GL and GW was analyzed by linear regression, which showed both positive and negative correlation. Gonado-somatic index (GSI), hepato-somatic index (HSI) and spleen-somatic index (SSI) ranged from 0.135 to 21.28, 0.358 to 21.33 and 0.126 to 1.08 in females and the corresponding values for males were 0.17 to 10.68, 0.619 to 3.25 and 1.25 to 2.33 respectively.

Detecting positive darwinian selection in brain-expressed genes during human evolution

To understand the genetic basis that underlies the phenotypic divergence between human and non-human primates, we screened a total of 7176 protein-coding genes expressed in the human brain and compared them with the chimpanzee orthologs to identity genes

Design-phase-specific selection of user research methods

For increasing the usability of a medical device the usability engineering standards IEC 60601-1-6 and IEC 62366 suggest incorporating user information in the design and development process. However, practice shows that integrating user information and the related investigation of users, called user research, is difficult in the field of medical devices. In particular, identifying the most appropriate user research methods is a difficult process. This difficulty results from the complexity of the medical device industry, especially with respect to regulations and standards, the characteristics of this market and the broad range of potential user research methods available from various research disciplines. Against this background, this study aimed at guiding designers and engineers in selecting effective user research methods according to their stage in the design process. Two approaches are described which reduce the complexity of method selection by summarizing the high number of methods into homogenous method classes. These approaches are closely connected to the medical device industry characteristic design phases and therefore provide the possibility of selecting design-phase- specific user research methods. In the first approach potential user research methods are classified after their characteristics in the design process. The second approach suggests a method summarization according to their similarity in the data collection techniques and provides an additional linkage to design phase characteristics. Both approaches have been tested in practice and the results show that both approaches facilitate user research method selection. © 2009 Springer-Verlag.

Size related feeding patterns and electivity indices of silver barb (Barbodes gonionotus Bleeker) from a pond, Bangladesh

The feeding patterns with respect to quality and quantity of food of silver barb, Barbodes gonionotus varied with their size and development. The results indicated that the fish in the size group I (7-25 mm TL) were fairly omnivore with particular liking for rotifera, green and blue-green algae while the size group II (25.1-44 mm TL) and III (44.1-55 mm TL) were omnivore with higher tendency of feeding on debris, aquatic plants, green algae, blue-green algae and rotifera. However, the fish of the size group IV (55.1-80 mm TL) were found to be herbivore with feeding preference for aquatic plants, green and blue-green algae. In all the size groups, debris was the most dominant food item. Feeding preference of the fish showed clear ontogenetic shift. The electivity indices revealed that the fish were selective feeder.

Selection of freshwater pearl mussel species for mantle transplantation in Bangladesh

Allograft mantle transplantations were studied in six species of freshwater mussels~ Lamellidens marginalis, L. corrianus~ L. jenkinsianus_, L. phenchooganjensis~ Parreysia corrugata and P. favidens by transplanting foreign mantle tissue into the mantle tissue of a host mussel. After three months of rearing, maximum survivability and pearl formation were observed in L. marginalis and L. jenkinsianus followed by L. corrianus and L. phenchooganjensis. Very poor results were observed in case of Parreysia corrugata and P. favidens. In addition to the natural pearl producing capacity of individual species, survivability and pearl production were related to the size of the mussel species. L. marginalis has been identified as the best species for mantle transplantation in Bangladesh.