A comparison of new in-pond grading technology to live-car grading for food-sized channel catfish (Ictalurus punctatus)

Grading trials were performed in experimental and commercial catfish ponds to compare an in-pond horizontal floating bar grader to current live-car grading. Three replicate trials were conducted in experimental ponds at three different temperature ranges (warm, >26 °C; cool, 13–26 °C; cold, <13 °C) with catfish size groups stocked in ratios of either 75:25, 50:50, or 25:75 sub-marketable (<0.57 kg) to marketable fish (≥0.57 kg). Commercial pond trials were replicated three times at each temperature range with a fish size range typical of ponds ready to harvest. Stress experienced by fish during harvest and grading was measured by mean serum glucose and cortisol levels. Grading speed was greater (P < 0.05) with the UAPB grader (105–449 kg/min) than the traditional live-car grader (0.5–0.6 kg/min). The UAPB grader decreased (P < 0.05) the proportion of sub-marketable fish during all trials. In contrast, the live car did not reduce the proportion of sub-marketable fish with the experimental methods used in this study during commercial trials or in the 25:75 distributions during warm and cold temperature trials in experimental ponds. The UAPB grader returned an average two to four times (range of 2–52) more sub-marketable fish by weight to the pond than the traditional live car method. Glucose and cortisol levels in fish graded with the two technologies were not significantly different. The UAPB grader sorted fish more accurately, consistently, and quickly than the live car at all temperatures in both experimental and commercial trials.     

Genetic variability and heritability estimates for hardseededness and flowering in balansa clover (Trifolium michelianum Savi) populations

Suitability of annual pasture legume species like balansa clover (Trifolium michelianum Savi) in southern Australian farming systems depends on their hardseededness and time to flowering. Late maturing varieties with increased rate of hardseed breakdown, particularly in the late summer—early autumn period are desirable to ensure reliable regeneration in permanent pastures. Two half-sib family balansa clover populations were used to estimate heritability for the rate of breakdown of hardseededness and time to flowering. High narrow-sense heritability estimates (90.5–96.1%, rate of hardseed breakdown; 85.9–94.5%, time to flowering) were obtained, and were mainly attributed to additive gene effects. There was no relationship between rate of hardseed breakdown and time to flowering in Group1 half-sib family, which indicated that selection for both traits could be undertaken independently. In half-sib family Group 2 the relationship between the two traits suggested the possibility of selecting late maturing cultivars with increased rate of hardseed breakdown. Significant differences in time to flowering and rate of hardseed breakdown both within and between the two half-sib family groups suggested that phenotypic recurrent selection would be effective in improving the traits in these populations.     

Age-dependent patterns of bovine tuberculosis in cattle

Bovine tuberculosis (BTB) is an important livestock disease, seriously impacting cattle industries in both industrialised and pre-industrialised countries. Like TB in other mammals, infection is life long and, if undiagnosed, may progress to disease years after exposure. The risk of disease in humans is highly age-dependent, however in cattle, age-dependent risks have yet to be quantified, largely due to insufficient data and limited diagnostics. Here, we estimate age-specific reactor rates in Great Britain by combining herd-level testing data with spatial movement data from the Cattle Tracing System (CTS). Using a catalytic model, we find strong age dependencies in infection risk and that the probability of detecting infection increases with age. Between 2004 and 2009, infection incidence in cattle fluctuated around 1%. Age-specific incidence increased monotonically until 24–36 months, with cattle aged between 12 and 36 months experiencing the highest rates of infection. Beef and dairy cattle under 24 months experienced similar infection risks, however major differences occurred in older ages. The average reproductive number in cattle was greater than 1 for the years 2004–2009. These methods reveal a consistent pattern of BTB rates with age, across different population structures and testing patterns. The results provide practical insights into BTB epidemiology and control, suggesting that targeting a mass control programme at cattle between 12 and 36 months could be beneficial.     

Efficient bipedal robots based on passive-dynamic walkers

Passive-dynamic walkers are simple mechanical devices, composed of solid parts connected by joints, that walk stably down a slope. They have no motors or controllers, yet can have remarkably humanlike motions. This suggests that these machines are useful models of human locomotion; however, they cannot walk on level ground. Here we present three robots based on passive-dynamics, with small active power sources substituted for gravity, which can walk on level ground. These robots use less control and less energy than other powered robots, yet walk more naturally, further suggesting the importance of passive-dynamics in human locomotion.     

Interplay between changing climate and species' ecology drives macroevolutionary dynamics

Ecological change provokes speciation and extinction, but our knowledge of the interplay among the biotic and abiotic drivers of macroevolution remains limited. Using the unparalleled fossil record of Cenozoic macroperforate planktonic foraminifera, we demonstrate that macroevolutionary dynamics depend on the interaction between species' ecology and the changing climate. This interplay drives diversification but differs between speciation probability and extinction risk: Speciation was more strongly shaped by diversity dependence than by climate change, whereas the reverse was true for extinction. Crucially, no single ecology was optimal in all environments, and species with distinct ecologies had significantly different probabilities of speciation and extinction. The ensuing macroevolutionary dynamics depend fundamentally on the ecological structure of species' assemblages.     

Lack of correlation between the levels of soluble cytotoxic T-lymphocyte associated antigen-4 (CTLA-4) and the CT-60 genotypes

Background

Cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) plays a critical role in downregulation of antigen-activated immune response and polymorphisms at the CTLA-4 gene have been shown to be associated with several autoimmune diseases including type-1 diabetes (T1D). The etiological mutation was mapped to the CT60-A/G single nucleotide polymorphism (SNP) that is believed to control the processing and production of soluble CTLA-4 (sCTLA-4).

Methods

We therefore determined sCTLA-4 protein levels in the sera from 82 T1D patients and 19 autoantibody positive (AbP) subjects and 117 autoantibody negative (AbN) controls using ELISA. The CT-60 SNP was genotyped for these samples by using PCR and restriction enzyme digestion of a 268 bp DNA segment containing the SNP. Genotyping of CT-60 SNP was confirmed by dye terminating sequencing reaction.

Results

Higher levels of sCTLA-4 were observed in T1D (2.24 ng/ml) and AbP (mean = 2.17 ng/ml) subjects compared to AbN controls (mean = 1.69 ng/ml) with the differences between these subjects becoming significant with age (p = 0.02). However, we found no correlation between sCTLA-4 levels and the CTLA-4 CT-60 SNP genotypes.

Conclusion

Consistent with the higher serum sCTLA-4 levels observed in other autoimmune diseases, our results suggest that sCTLA-4 may be a risk factor for T1D. However, our results do not support the conclusion that the CT-60 SNP controls the expression of sCTLA-4.