The genetics of a managed Atlantic salmon stock and implications for conservation.

Numerous populations of wild Atlantic salmon have declined in recent years. The Atlantic salmon in Girnock Burn, an upland spate tributary of the River Dee, Scotland have been monitored intensely by government scientists since 1966. The burn is equipped with upstream and downstream traps, which have enabled monitoring of juveniles leaving the burn and adults returning to it since 1966. Recently, due to a decline in numbers of female returns, a supportive breeding program was instigated. Using microsatellite-based DNA profiling, this study exploited existing and novel tissue samples to investigate aspects of Atlantic salmon biology and conservation. A panel of up to 12, mainly highly polymorphic, microsatellite loci were employed to derive allele frequency data and to resolve parentage in egg, parr, smolt and anadromous adult samples taken between 1991 and 2004. Genotyping error was investigated and rectified where possible. Overall, the detected error was low (c.0.5%), providing confidence in subsequent population and parentage analyses. The error rate involved in estimating the age of salmon in Girnock Burn from scale readings was also estimated (c.2-8%). A study of the dynamics of natural spawning, based on the parentage of parr, confirmed that multiple matings by anadromous returns of both sexes were prevalent. Not all anadromous returns were apparently successful spawners; data from parr and existing redd samples failed to detect a contribution from 35% of males and 29% of females. An important aspect of the work was to determine the success of the supportive breeding program. Results showed that, in comparison to natural spawning, the program gave a more complete and even representation of adult spawners in offspring. In addition, there was no detectable difference in the output (number of smolts) of the two schemes when the number of eggs used in each was taken into account. The distribution of juvenile kin (parr aged 1+) within the burn was determined, which revealed clustering of full and half sib groups. This was found to impact on standard population genetic analyses. Adjacent samples (n = 50), each sampled over a c.1.5 km stretch of river were shown to exhibit significant allelic differentiation, while samples from individuals selected at random over a 7.5km stretch did not. Parentage analysis of adult returns showed that the number of returns likely to be philopatric was higher than would be predicted solely from physical tagging data. This was attributed to ‘leakage’ of the downstream parr/smolt trap. An initial investigation into the role of mature parr in adaptation of populations to the environment was made, although sire type (i.e. anadromous male or mature parr) was not found to affect survival in the freshwater environment in this case. More research into this aspect is warranted, particularly with the possible impact of predicted climate change on male parr maturity. A comparison of genetic diversity through time (measured by allelic richness) revealed no detectable change between 1991 and 2004. Estimates of the effective population size using different genetic (temporal) methods were associated with a large degree of uncertainty, and were surprisingly high (ranging from 595 to 1992) c.f. demographic based estimates (ranging from 95 to 144), which was likely to be due in part to violation of assumptions made in the calculations. These findings have highlighted a range of avenues for future lines of research, should aid in the management of Atlantic salmon within Girnock Burn and assist in the design of sampling regimes.NERC, University of Stirlin

Computer simulation of coronary blood flow

A computer model to simulate coronary fluid dynamics has been developed which can give some insight into the role of hemodynamics in health and disease. Although this study focuses mainly on coronary blood flow, the complete model consists of all major branches of the systemic circulation as well as the left epicardial coronary circulation;The flow equations are obtained by integrating the one-dimensional continuity and momentum equations over the cross-section of the artery to give a relationship between the primary variables of interest, the pressure and flowrate. An arctangent model was used as a constitutive equation to describe the pressure-area relationship for the arterial wall. The distal point of each terminal branch is modeled using a lumped parameter impedance to account for all the cumulative effects of the distal vasculature. The systemic circulation terminal impedances each contain a simple constant property modified windkessel. The coronary terminal impedances are modeled using similar lumped parameter models. The first model employed was based on the waterfall concept of collapsible tube dynamics. The second model was slightly more sophisticated and was based on the intramyocardial pump concept. Unlike the systemic terminal impedances, the coronary terminal resistance and compliance values are allowed to vary throughout the cardiac cycle according to the extravascular compressive pressure created by the contracting myocardium. The above system of nonlinear partial differential equations was discretized using a finite difference formulation and solved numerically;Both coronary models developed could predict realistic flow patterns in the epicardial arteries. The computer model is also capable of investigating the effects of coronary stenoses with vascular bypasses on epicardial blood flow. The limitations of the model are mainly related to the assumptions needed to obtain the simplified form of the governing equations and the extensive amount of parameter data that are required. Overall, this type of model offers a useful tool for studying the fluid dynamics of the human circulation

Yoshinori Ohsumi's Nobel Prize for mechanisms of autophagy: from basic yeast biology to therapeutic potential.

On 3 October 2016, Japanese cell biologist Yoshinori Ohsumi was awarded the Nobel Prize in Physiology or Medicine 'for his discoveries of mechanisms for autophagy'; autophagy being an intracellular degradation pathway that helps maintain cytoplasmic homeostasis. This commentary discusses Ohsumi's Nobel prize-winning work in context, before explaining the clinical relevance of autophagy

Reimagining the 4M Framework in Educational Development for SoTL

In this paper, we seek to contextualize our work in SoTL-focused educational development and those who work to support others in SoTL, as interstitially spaced across the 4M Framework, re-envisioned as a flexible but formalized professional continua. The establishment of a model for educational development SoTL-related activity allows for the opportunity to explore how this work is done in a systematic manner. We offer our ideas and visions through, what we term, the 4M Continua for Educational Development as a possible understanding of the work that SoTL-focused educational developers do, as well as those who engage in educational development more broadly. While the 4M Framework provides a guide through four interrelated organizational lenses: micro; meso; macro; and mega, we have adapted a model to situate educational development work using the 4M Framework to inform the ways in which we do, contribute to, consume, advocate, and support SoTL broadly, including at local, provincial, national, and international levels. The 4M Continua can be an avenue for those who do educational development to describe their work, where the work is situated, and how support can be offered throughout the community

Reimagining the 4M Framework in Educational Development for SoTL

In this paper, we seek to contextualize our work in SoTL-focused educational development and those who work to support others in SoTL, as interstitially spaced across the 4M Framework, re-envisioned as a flexible but formalized professional continua. The establishment of a model for educational development SoTL-related activity allows for the opportunity to explore how this work is done in a systematic manner. We offer our ideas and visions through, what we term, the 4M Continua for Educational Development as a possible understanding of the work that SoTL-focused educational developers do, as well as those who engage in educational development more broadly. While the 4M Framework provides a guide through four interrelated organizational lenses: micro; meso; macro; and mega, we have adapted a model to situate educational development work using the 4M Framework to inform the ways in which we do, contribute to, consume, advocate, and support SoTL broadly, including at local, provincial, national, and international levels. The 4M Continua can be an avenue for those who do educational development to describe their work, where the work is situated, and how support can be offered throughout the community. Click here to read the corresponding ISSOTL blog post

OCC Letter from Ronald H Frake to Geoffrey O Coley Re Citibank Derivatives Examination Findings

This letter is addressed to Geoffrey O Cole

OCC Letter from Michael Sullivan and Ron Frake to John Lyons Re Subprime CDO Valuation and Oversight Review Conculsion Memorandum

This letter is addressed to John Lyon