Large-scale unit commitment under uncertainty: an updated literature survey

The Unit Commitment problem in energy management aims at finding the optimal production schedule of a set of generation units, while meeting various system-wide constraints. It has always been a large-scale, non-convex, difficult problem, especially in view of the fact that, due to operational requirements, it has to be solved in an unreasonably small time for its size. Recently, growing renewable energy shares have strongly increased the level of uncertainty in the system, making the (ideal) Unit Commitment model a large-scale, non-convex and uncertain (stochastic, robust, chance-constrained) program. We provide a survey of the literature on methods for the Uncertain Unit Commitment problem, in all its variants. We start with a review of the main contributions on solution methods for the deterministic versions of the problem, focussing on those based on mathematical programming techniques that are more relevant for the uncertain versions of the problem. We then present and categorize the approaches to the latter, while providing entry points to the relevant literature on optimization under uncertainty. This is an updated version of the paper "Large-scale Unit Commitment under uncertainty: a literature survey" that appeared in 4OR 13(2), 115--171 (2015); this version has over 170 more citations, most of which appeared in the last three years, proving how fast the literature on uncertain Unit Commitment evolves, and therefore the interest in this subject

Pregnancy in Obese Mice Protects Selectively against Visceral Adiposity and Is Associated with Increased Adipocyte Estrogen Signalling

Maternal obesity is linked with increased adverse pregnancy outcomes for both mother and child. The metabolic impact of excessive fat within the context of pregnancy is not fully understood. We used a mouse model of high fat (HF) feeding to induce maternal obesity to identify adipose tissue-mediated mechanisms driving metabolic dysfunction in pregnant and non-pregnant obese mice. As expected, chronic HF-feeding for 12 weeks preceding pregnancy increased peripheral (subcutaneous) and visceral (mesenteric) fat mass. However, unexpectedly at late gestation (E18.5) HF-fed mice exhibited a remarkable normalization of visceral but not peripheral adiposity, with a 53% reduction in non-pregnant visceral fat mass expressed as a proportion of body weight (P<0.001). In contrast, in control animals, pregnancy had no effect on visceral fat mass proportion. Obesity exaggerated glucose intolerance at mid-pregnancy (E14.5). However by E18.5, there were no differences, in glucose tolerance between obese and control mice. Transcriptomic analysis of visceral fat from HF-fed dams at E18.5 revealed reduced expression of genes involved in de novo lipogenesis (diacylglycerol O-acyltransferase 2--Dgat2) and inflammation (chemokine C-C motif ligand 20--Ccl2) and upregulation of estrogen receptor α (ERα) compared to HF non pregnant. Attenuation of adipose inflammation was functionally confirmed by a 45% reduction of CD11b+CD11c+ adipose tissue macrophages (expressed as a proportion of all stromal vascular fraction cells) in HF pregnant compared to HF non pregnant animals (P<0.001). An ERα selective agonist suppressed both de novo lipogenesis and expression of lipogenic genes in adipocytes in vitro. These data show that, in a HF model of maternal obesity, late gestation is associated with amelioration of visceral fat hypertrophy, inflammation and glucose intolerance, and suggest that these effects are mediated in part by elevated visceral adipocyte ERα signaling

EFFECTS OF CORN-STARCH AND DEXTROSE ON OYSTERS

Volume: 20Start Page: 352End Page: 35

Representative bureaucracy in Canada: multiculturalism in the public service

As the population in many western democracies becomes increasingly diverse as a result of global migration, national governments are challenged with settling and integrating minority groups into mainstream society. Yet accomplishing sustainable integration is difficult and issue-laden, as anti-immigrant sentiments, discrimination and barriers to employment, tokenism, and a lack of opportunities continue to affect minority participation in the host society. In that respect, Canada has adopted Multiculturalism as a public policy instrument to nation-building. In order to meet the needs of its diverse population, Canada has also implemented Employment Equity in its civil service as a measure to achieve representative bureaucracy among its cadre of civil servants. To date, the Canadian Multiculturalism policy has been met with a relative degree of success in comparison to other countries with strong immigrant receiving traditions. This comparative level of success is due in part to Canada’s emphasis on immigrant integration (vis-a-vis assimilation) where both host group members and minority group members adopt and adapt to each other’s cultures. This chapter details how Canada’s unique English and French roots, immigration history, and pluralist view of citizenship have allowed Multiculturalism to be deployed as a public policy tool to successfully integrate minorities and citizens with immigrant backgrounds in comparison to other countries. We also discuss how Multiculturalism has been used to mitigate some of the issues which arise from diverse workforces. We close with a review on how Canada has engaged its civil service to help achieve its ideals as a multicultural nation