Daily rhythm of cerebral blood flow velocity

Background  

CBFV (cerebral blood flow velocity) is lower in the morning than in the afternoon and evening. Two hypotheses have been proposed to explain the time of day changes in CBFV: 1) CBFV changes are due to sleep-associated processes or 2) time of day changes in CBFV are due to an endogenous circadian rhythm independent of sleep. The aim of this study was to examine CBFV over 30 hours of sustained wakefulness to determine whether CBFV exhibits fluctuations associated with time of day.     

Value-added sampling for fishery independent surveys: Don’t stop after you’re done counting and measuring

Most fishery independent surveys count, weigh, and measure the majority of species caught. Many surveys also collect selected body structures for in-lab age determinations for selected species. We provide examples from the Northeast Fisheries Science Center's (NEFSC) bottom trawl survey that detail the development of at-sea sampling to elucidate age, growth, maturity, fecundity, spawning season, stomach contents, diet composition, condition, habitat types and prey preferences, basic oceanography (or limnology), and bioenergetics for a suite of diverse species. We show how the development of new methodologies and technologies has decreased both deck-time and time in the lab for processing many of the samples required to provide information on the topics listed above. As new technologies develop to make our trawl catch processing more efficient, we assert that we can notably increase the amount of information collected from trawl surveys with little additional effort. We show that with marginally additional catch processing time on the deck, at-sea sampling can provide a significant return on the knowledge of aquatic and marine resource species, non-resource species, habitats, food webs, and the ecosystems within which they occur. As observing systems continue to expand their remit to provide ecosystem management advice, the need for increased efficiencies on fisheries surveys will remain.     

Ages for the Middle Stone Age of southern Africa: implications for human behavior and dispersal

The expansion of modern human populations in Africa 80,000 to 60,000 years ago and their initial exodus out of Africa have been tentatively linked to two phases of technological and behavioral innovation within the Middle Stone Age of southern Africa-the Still Bay and Howieson's Poort industries-that are associated with early evidence for symbols and personal ornaments. Establishing the correct sequence of events, however, has been hampered by inadequate chronologies. We report ages for nine sites from varied climatic and ecological zones across southern Africa that show that both industries were short-lived (5000 years or less), separated by about 7000 years, and coeval with genetic estimates of population expansion and exit times. Comparison with climatic records shows that these bursts of innovative behavior cannot be explained by environmental factors alone.     

In vitro fermentation of bacterial cellulose composites as model dietary fibers

Plant cell walls within the human diet are compositionally heterogeneous, so defining the basis of nutritive properties is difficult. Using a pig fecal inoculum, in vitro fermentations of soluble forms of arabinoxylan, mixed-linkage glucan, and xyloglucan were compared with the same polymers incorporated into bacterial cellulose composites. Fermentation rates were highest and similar for the soluble polysaccharides. Cellulose composites incorporating those polysaccharides fermented more slowly and at similar rates to wheat bran. Bacterial cellulose and cotton fermented most slowly. Cellulose composite fermentation resulted in a different short-chain fatty acid profile, compared with soluble polysaccharides, with more butyrate and less propionate. The results suggest that physical form is more relevant than the chemistry of plant cell wall polysaccharides in determining both rate and end-products of fermentation using fecal bacteria. This work also establishes bacterial cellulose composites as a useful model system for the fermentation of complex cell wall dietary fiber.     

Comparison of freshwater and marine performances of all‐female diploid and triploid Atlantic salmon (Salmo salar L.)

The performance of all‐female diploid (AF2N) and triploid (AF3N) Atlantic salmon were compared in fresh water, under commercial production conditions in 1995 and 1996 year classes. The performance of the 1996 year class was also assessed for 14 months in a commercial sea farm. Freshwater mortality was higher in the triploid groups. The majority of losses occurred in the early stages of egg development and during the first feeding period, when the incidence of non‐feeding fry was consistently higher. In growth studies, although diploid fry were significantly heavier during first feeding there were no significant differences in weight between groups some 8 months after fertilization or in presmolt growth periods from February to April in 1996 and 1997. Smolting rates were high (range 93.5–95.3%) and the incidence of deformities was low (< 1%) in both groups. Marine survival was lower in the triploid group, largely as a consequence of higher losses sustained during a period of chronic stress, when triploid losses were 9% higher. Growth patterns were similar for the first 11 months in sea water. Although graded triploid salmon were heavier in January 1998 (AF3N 1.62 ± 0.033 kg, AF2N 1.46 ± 0.36 kg, P < 0.05), when the fish were harvested in May 1998 diploid salmon were significantly heavier than triploid salmon although there was no significant difference in weights after evisceration (AF3N 2.40 kg ± 0.04 AF2N 2.49 kg ±0.03). The increase in weight of the diploids between winter and harvest reflects the growth spurt that occurs in maturing fish in the spring. Overall yields of triploid salmon in salt water were lower as a result of inferior survival.     

Improvement of the nutritive value of soybean meal by protease and alpha-galactosidase treatment in broiler cockerels and broiler chicks

1. Tube-fed broiler cockerels were used in three experiments to measure the effect of different enzyme treatments on true metabolisable energy (TME) and true nitrogen digestibility (TND) of commercial solvent-extracted, heat-treated soybean meal (SBM). 2. In experiment 1, proteases P2 and P3 (from Aspergillus niger) and alpha-galactosidase (from A. oryzae) improved TME and TND while protease P1 (from Bacillus subtilis) had little effect. The effects of enzyme treatment were similar whether treatment was applied by pre-incubation of enzymes (proteases P1, P2 and P3, 1.0 g/kg; alpha-galactosidase, 0.1 g/kg) with SBM for 2 h at 50 degrees C or by simple mixing of enzymes (proteases P1, P2 and P3, 0.25 g/kg; alpha-galactosidase, 0.1 g/kg) with SBM prior to feeding. 3. In experiment 2, the effects of mixing SBM with each of protease P1 (0 or 0.25 g/kg), protease P3 (0 or 0.25 g/kg) or alpha-galactosidase (0 or 0.1 g/kg) alone or in all possible combinations were studied. Effects of protease P1 were limited, but protease P3 and alpha-galactosidase improved TME and TND. There were significant interactions between protease P3 and alpha-galactosidase for both TME and TND; the response when enzymes were applied together was less than that expected from application of the enzyme preparations individually. 4. In experiment 3, the effect of varying the concentration of protease P3 (0, 0.1, 0.25 and 1.0 g/kg SBM dry matter) and alpha-galactosidase (0, 0.025, 0.0625 and 0.25 g/kg SBM dry matter) mixed with SBM alone or in all possible combinations of protease P3 and alpha-galactosidase were assessed. Increases in TME and TND for both enzymes were non-linear with the greatest response occurring at the lowest concentration of each enzyme. There were also interactions between the two enzyme preparations. 5. Finally, either protease P3 (0, 0.1 and 1.0 g/kg SBM dry matter) or alpha-galactosidase (0, 0.025 and 0.25 g/kg SBM dry matter) were mixed with SBM alone or in all possible combinations and treated SBMs incorporated into semi-purified diets containing 450 g SBM/kg as the sole source of dietary N and offered to growing broiler chicks for 21 d. Similar patterns of increases in chick growth rate and diet digestibility to those recorded in experiment 3 were obtained when protease P3 and alpha-galactosidase where included in the diets. 6. It is concluded that responses measured by tube-feeding SBM treated with protease P3 and alpha-galactosidase were similar to responses obtained with growing broiler chicks. Further, these responses were obtained by simple addition of enzymes to diets and nutritive value of SBM was improved by both protease and alpha-galactosidase treatment.     

Serum thromboxane generation by platelets in several domestic animal species

Blood collected from calves, sheep, goats, pigs, dogs, horses, ponies and donkeys, was allowed to clot under standard conditions. Thromboxane B2 generated during the clotting process was measured by radioimmunoassay in serum harvested from each sample. Highly significant differences were found between species and also between genera within a species. Highest concentrations of thromboxane B2 were detected in the dog samples (887.7 +/- 123.7 ng/ml) and lowest concentrations in samples from sheep (2.7 +/- 0.2 ng/ml). The amount of thromboxane produced per unit number of circulating platelets or per unit volume of platelets in each species was not the same and it would appear that platelets from each species have different inherent ability to produce thromboxane under the stimulus applied, or that some species generate thromboxane from other sources during the clotting process.