Maximizing the value of thermally integrated hydroelectric generating facilities

This paper presents a demonstration of a phenomenon known as hydro-shifting, which relates to the provision of two sources of electric power to customers. The extent that these resources are used in each period is shown to depend partly on the time of day in which the power is provided. Although the dispatcher could combine thermal resales with hydro power in equal proportions for its customers in both periods, a rationalization is presented that justifies the withholding of some water until the peak period, with the balance of off-peak demand satisfied in larger proportions by resales of thermal power. Value is optimized for electrical generation, and environmental externalities are incorporated as minimum or maximum flow limitations. This paper also presents evidence that the optimal degree of hydro-shifting depends on the size of the reservoir adjacent to the dam, with this shifting behavior being more pronounced for larger reservoirs

Efficacy and Safety of Mipomersen, an Antisense Inhibitor of Apolipoprotein B, in Hypercholesterolemic Subjects Receiving Stable Statin Therapy

Objectives The aim of this study was to evaluate the efficacy and safety of mipomersen in hypercholesterolemic subjects taking stable statin therapy. Background Mipomersen is an apolipoprotein (apo) B synthesis inhibitor that has demonstrated significant reductions in apo B and low-density lipoprotein (LDL) cholesterol in Phase 1 clinical trials in healthy volunteers. Methods A randomized, placebo-controlled, dose-escalation Phase 2 study was designed to evaluate the effects of mipomersen in hypercholesterolemic subjects taking stable statin therapy. Seventy-four subjects were enrolled sequentially into 1 of 6 dose cohorts at a 4:1 (active/placebo) ratio. Subjects received 7 doses of 30 to 400 mg over 5 weeks in the first 5 cohorts and 15 doses of 200 mg over 13 weeks in the sixth cohort. Pre-specified end points included percentage change from baseline in apo B and LDL cholesterol. Safety was assessed with laboratory test results and by the incidence and severity of adverse events. Results The apo B and LDL cholesterol were reduced by 19% to 54% and 21% to 52%, respectively, at doses of 100 mg/week mipomersen and higher in the 5-week treatment cohorts. Efficacy seemed to increase upon treatment for 13 weeks at a dose of 200 mg/week. Injection site reactions (mild to moderate erythema [90%]) and hepatic transaminase increases (17%) were the most common adverse events, leading to discontinuation in 2 subjects and 1 subject, respectively. In the 13-week treatment cohort, 5 of 10 subjects (50%) had elevations >= 3x the upper limit of normal, 4 of which persisted on 2 consecutive occasions. Conclusions Mipomersen might hold promise for treatment of patients not reaching target LDL cholesterol levels on stable statin therapy. Further studies are needed to address the mechanisms and clinical relevance of transaminase changes after mipomersen administration. (Dose-Escalating Safety Study in Subjects on Stable Statin Therapy; NCT00231569) (J Am Coll Cardiol 2010;55:1611-8) (C) 2010 by the American College of Cardiology FoundationVascular Biology and Interventio

The unique methodological challenges of winter limnology

Winter is an important season for many limnological processes, which can range from biogeochemical transformations to ecological interactions. Interest in the structure and function of lake ecosystems under ice is on the rise. Although limnologists working at polar latitudes have a long history of winter work, the required knowledge to successfully sample under winter conditions is not widely available and relatively few limnologists receive formal training. In particular, the deployment and operation of equipment in below 0 C temperatures pose considerable logistical and methodological challenges, as do the safety risks of sampling during the ice covered period. Here, we consolidate information on winter lake sampling and describe effective methods to measure physical, chemical, and biological variables in and under ice. We describe variation in snow and ice conditions and discuss implications for sampling logistics and safety. We outline commonly encountered methodological challenges and make recommendations for best practices to maximize safety and efficiency when sampling through ice or deploying instruments in ice-covered lakes. Application of such practices over a broad range of ice-covered lakes will contribute to a better understanding of the factors that regulate lakes during winter and how winter conditions affect the subsequent ice-free period