Behavioral and Physiological Adaptations of Largemouth Bass (Micropterus Salmoides) to Low-Salinity Environments.

A study of the biology, movements, behavior, and physiology of largemouth bass (Micropterus salmoides) from a low-salinity marsh in Lafourche Parish, Louisiana was conducted from March 1985 to December 1987. Comparative data were also collected for freshwater largemouth bass from Ben Hur Lake and False River, Louisiana. Marsh largemouth bass were small compared to freshwater bass of similar age, although growth rates of older marsh bass equaled or exceeded those of freshwater fish. Marsh bass relative weight indicated excellent condition during all seasons, while freshwater bass exhibited reduced condition in early spring and fall. Characteristic body morphology and growth of marsh bass suggest an adaptation to low-salinity environments. Salinity did not influence daily movements of ultrasonically-tagged largemouth bass, although salinity increases in late summer may have induced large-scale seasonal movements. Though tagged fish could not be located after salinities reached 8 parts per thousand (ppt), largemouth bass smaller than tagged individuals were collected in the study area. The presence of large predators combined with potential stressful physicochemical conditions may influence movements of largemouth bass in low-salinity environments. Salinity preferences of adult and young-of-the-year (YOY) largemouth bass indicated YOY marsh and freshwater bass preferred 0 ppt. Although adult marsh and freshwater bass preferred 3 ppt, mean number of observations at 0 ppt was significantly greater for freshwater bass, while mean number of observations at 3 ppt was significantly greater for marsh bass. Differences in salinity selection by adult largemouth bass between collection sites may be the result of long-term exposure to salinity. Experiments in which marsh and freshwater largemouth bass were exposed to 0, 4, 8, and 12 ppt salinity indicated no significant differences in plasma osmolalities, electrolyte concentrations, or gill ATPase activities between marsh and freshwater fish exposed to 0, 4, or 12 ppt. Exposure to 12 ppt resulted in osmotic stress in largemouth bass from both collection sites. At 8 ppt, marsh bass had significantly higher plasma chemistry values and lower gill ATPase activities than freshwater fish. Marsh bass appear to have adapted to environments of variable salinity by reducing energetic expenditures related to osmoregulation

Handedness as a marker of cerebral lateralization in children with and without autism

We employed a multiple case studies approach to investigate lateralization of hand actions in typically and atypically developing children between 4 and 5 years of age. We report on a detailed set of over 1200 hand actions made by four typically developing boys and four boys with autism. Participants were assessed for unimanual hand actions to both objects and the self (self-directed behaviors). Individual and group analyses suggest that typically developing children have a right hand dominance for hand actions to objects and a left hand dominance for hand actions for self-directed behaviors, revealing a possible dissociation for functional specialization of the left and right hemispheres respectively. Children with autism demonstrated mixed-handedness for both target conditions, consistent with the hypothesis that there is reduced cerebral specialization in these children. The findings are consistent with the view that observed lateralized motor action can serve as an indirect behavioral marker for evidence of cerebral lateralization

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Self-Healing of Core–Shell Magnetic Polystyrene Nanocomposites

High heat generation is reported in core–shell magnetic nanoparticle polystyrene (PS) nanocomposites (3.5, 10 wt %) when they are placed in a high-frequency ac magnetic field. These magnetic nanoparticles with cobalt iron oxide core and manganese iron oxide shell were synthesized and characterized by wide-angle X-ray scattering (WAX), thermal gravimetric analysis (TGA), transmission electron microscopy (TEM), and ac field gradient magnetometery. When placed in a high-frequency ac magnetic field, the thermal energy generated in the magnetic polystyrene nanocomposites resulted in a surface temperature increase. The heat generation is attributed to the contribution of Néel relaxation and hysteresis of the core–shell magnetic nanoparticles in the solid state. The maximum surface temperature increased with increasing nanoparticle content and resulted in melting of the magnetic polystyrene nanocomposite