Complex pattern of genetic structuring in the Atlantic salmon (Salmo salar L.) of the River Foyle system in northwest Ireland: disentangling the evolutionary signal from population stochasticity

Little is known about the microevolutionary processes shaping within river population genetic structure of aquatic organisms characterized by high levels of homing and spawning site fidelity. Using a microsatellite panel, we observed complex and highly significant levels of intrariver population genetic substructure and Isolation-by-Distance, in the Atlantic salmon stock of a large river system. Two evolutionary models have been considered explaining mechanisms promoting genetic substructuring in Atlantic salmon, the member-vagrant and metapopulation models. We show that both models can be simultaneously used to explain patterns and levels of population structuring within the Foyle system. We show that anthropogenic factors have had a large influence on contemporary population structure observed. In an analytical development, we found that the frequently used estimator of genetic differentiation, F-ST, routinely underestimated genetic differentiation by a factor three to four compared to the equivalent statistic Jost's D-est (Jost 2008). These statistics also showed a near-perfect correlation. Despite ongoing discussions regarding the usefulness of "adjusted" F-ST statistics, we argue that these could be useful to identify and quantify qualitative differences between populations, which are important from management and conservation perspectives as an indicator of existence of biologically significant variation among tributary populations or a warning of critical environmental damage.

Suppression of the high affinity phosphate uptake system:A mechanism of arsenate tolerance in Holcus lanatus L.

In Holcus lanatus L. phosphate and arsenate are taken up by the same transport system. Short-term uptake kinetics of the high affinity arsenate transport system were determined in excised roots of arsenate-tolerant and non-tolerant genotypes. In tolerant plants the V_max of ion uptake in plants grown in phosphate-free media was decreased compared to non-tolerant plants, and the affinity of the uptake system was lower than in the non-tolerant plants. Both the reduction in V_max and the increase in K_m led to reduced arsenate influx into tolerant roots. When the two genotypes were grown in nutrient solution containing high levels of phosphate, there was little change in the uptake kinetics in tolerant plants. In non-tolerant plants, however, there was a marked decrease in the V_max to the level of the tolerant plants but with little change in the K_m. This suggests that the low rate of arsenate uptake over a wide range of differing root phosphate status is due to loss of induction of the synthesis of the arsenate (phosphate) carrier. © 1992 Oxford University Press.

Learning outcomes tracking system (L.O.T.S):seeing student progress as term progresses

At QUB we have constructed a system that allows students to self-assess their capability on the fine grained learning outcomes for a module and to update their record as the term progresses. In the system each of the learning outcomes are linked to the relevant teaching session (lectures and labs) and to [online] resources that students can access at any time. Students can structure their own learning experience to their needs to attain the learning outcomes. The system keeps a history of the student’s record, allowing the lecturer to observe how the students’ abilities progress over the term and to compare it to assessment results. The system also keeps of any of the resource links that student has clicked on.

An Evaluation of the Impact of the Prospective Payment System on Antidepressant Use in Nursing Home Residents

Objectives: To determine the impact of the prospective payment system (PPS) for skilled nursing facilities on the pharmacologic treatment of depression.

Methods: We used a quasi-experimental study comparing the pharmacological treatment rates for depression in the pre-PPS period (1997) to the post-PPS period (2000) in 8149 residents with documented depression living in over 500 nursing facilities in Ohio. Logistic regression models adjusting for clustering effects of residents residing in homes using generalized estimating equations provided estimates of the PPS effect on use of any antidepressant and the use of selective serotonin reuptake inhibitors (SSRIs). We evaluated the extent to which the PPS effect was modified by organizational characteristics, including structural characteristics, resource characteristics, and staff resources available in the homes.

Results: Overall, there was no difference in the likelihood of any antidepressant [odds ratio (OR), 1.05; 95% confidence interval (CI), 0.93 to 1.18, resident-adjusted model] or an SSRI being used (OR, 0.98; 95% CI, 0.86 to 1.12, resident-adjusted model) after the introduction of PPS compared with 1997 when this reimbursement system was not in place (referent group). These trends did not appear to be modified substantially by organizational characteristics.

Conclusion: Although PPS did not appear to have influenced the treatment of depression in nursing homes, systems that provide checks and balances in relation to PPS are warranted.

Differential expression of components of the cardiomyocyte adrenomedullin/intermedin receptor system following blood pressure reduction in nitric oxide-deficient hypertension.

Adrenomedullin (AM) and intermedin (IMD; adrenomedulln-2) are vasodilator peptides related to calcitonin gene-related peptide (CGRP). The actions of these peptides are mediated by the calcitonin receptor-like receptor (CLR) in association with one of three receptor activity-modifying proteins. CGRP is selective for CLR/receptor activity modifying protein (RAMP)1, AM for CLR/RAMP2 and -3, and IMD acts at both CGRP and AM receptors. In a model of pressure overload induced by inhibition of nitric-oxide synthase, up-regulation of AM was observed previously in cardiomyocytes demonstrating a hypertrophic phenotype. The current objective was to examine the effects of blood pressure reduction on cardiomyocyte expression of AM and IMD and their receptor components. Nomega-nitro-L-arginine methyl ester (L-NAME) (35 mg/kg/day) was administered to rats for 8 weeks, with or without concurrent administration of hydralazine (50 mg/kg/day) and hydrochlorothiazide (7.5 mg/kg/day). In left ventricular cardiomyocytes from L-NAME-treated rats, increases (-fold) in mRNA expression were 1.6 (preproAM), 8.4 (preproIMD), 3.4 (CLR), 4.1 (RAMP1), 2.8 (RAMP2), and 4.4 (RAMP3). Hydralazine/hydrochlorothiazide normalized systolic blood pressure (BP) and abolished mRNA up-regulation of hypertrophic markers sk-alpha-actin and BNP and of preproAM, CLR, RAMP2, and RAMP3 but did not normalize cardiomyocyte width nor preproIMD or RAMP1 mRNA expression. The robust increase in IMD expression indicates an important role for this peptide in the cardiac pathology of this model but, unlike AM, IMD is not associated with pressure overload upon the myocardium. The concordance of IMD and RAMP1 up-regulation indicates a CGRP-type receptor action; considering also a lack of response to BP reduction, IMD may, like CGRP, have an anti-ischemic function.