Stability Analysis of Wholesale Electricity Markets under Dynamic Consumption Models and Real-Time Pricing

This paper analyzes stability conditions for wholesale electricity markets under real-time retail pricing and realistic consumption models with memory, which explicitly take into account previous electricity prices and consumption levels. By passing on the current retail price of electricity from supplier to consumer and feeding the observed consumption back to the supplier, a closed-loop dynamical system for electricity prices and consumption arises whose stability is to be investigated. Under mild assumptions on the generation cost of electricity and consumers' backlog disutility functions, we show that, for consumer models with price memory only, market stability is achieved if the ratio between the consumers' marginal backlog disutility and the suppliers' marginal cost of supply remains below a fixed threshold. Further, consumer models with price and consumption memory can result in greater stability regions and faster convergence to the equilibrium compared to models with price memory alone, if consumption deviations from nominal demand are adequately penalized.Comment: 8 pages, 7 Figures, accepted to the 2017 American Control Conferenc

Lassa fever: A case report

Objective: Severe Lassa fever with high mortality among health care providers is usually a human to human infection that requires high index of suspicion to diagnose. This case report is to describe a peculiar case of Lassa fever among health worker.Result: A severe form of Lassa fever was diagnosed early in a healthcare provider and patient recovered fully.Conclusion: Fatality can be greatly reduced if early diagnosis as well as prompt specific treatment is instituted.Keywords: Lassa fever, Jo

Cryptosporidium Infection in Undernourished Children with HIV/AIDS in Jos, Nigeria

Background: AIDS and Protein energy malnutrition (PEM) severely impair the immune system Cryptosporidium has over the last two decades emerged as a life threatening disease. The study attempts to determine the prevalence of Cryptosporidium infection in malnourished children with HIV/AIDS. Method: Blood and stool samples of 52 HIV-seropositive children and another 52 HIV-sero-negative children aged 0-5 years were collected and screened for HIV and Cryptosporidium oocysts respectively. The sera were screened by double ELISA and the stool by the modified Ziehl-Neelsen method. Results: Out of the 52 HIV-seropositive undernourished, under-five children, none (0%) excreted Cryptosporidium oocyst in their stools while 2 (3.8%) of the control group excreted the oocyst. Conclusion: Cryptosporidium infection seems to be uncommon among undernourished under five children with HIV/AIDS in Jos

Lysophosphatidic Acid Induces MDA-MB-231 Breast Cancer Cells Migration through Activation of PI3K/PAK1/ERK Signaling

Enhanced motility of cancer cells is a critical step in promoting tumor metastasis. Lysophosphatidic acid (LPA), representing the major mitogenic activity in serum, stimulates migration in various types of cancer cells. However, the underlying signaling mechanisms for LPA-induced motility of cancer cells remain to be elucidated.In this study, we found that LPA dose-dependently stimulated migration of MDA-MB-231 breast cancer cells, with 10 µM being the most effective. LPA also increased ERK activity and the MEK inhibitor U0126 could block LPA-induced ERK activity and cell migration. In addition, LPA induced PAK1 activation while ERK activation and cell migration were inhibited by ectopic expression of an inactive mutant form of PAK1 in MDA-MB-231 cells. Furthermore, LPA increased PI3K activity, and the PI3K inhibitor LY294002 inhibited both LPA-induced PAK1/ERK activation and cell migration. Moreover, in the breast cancer cell, LPA treatment resulted in remarkable production of reactive oxygen species (ROS), while LPA-induced ROS generation, PI3K/PAK1/ERK activation and cell migration could be inhibited by N-acetyl-L-Cysteine, a scavenger of ROS.Taken together, this study identifies a PI3K/PAK1/ERK signaling pathway for LPA-stimulated breast cancer cell migration. These data also suggest that ROS generation plays an essential role in the activation of LPA-stimulated PI3K/PAK1/ERK signaling and breast cancer cell migration. These findings may provide a basis for designing future therapeutic strategy for blocking breast cancer metastasis

Hedging strategies for load-serving entities in wholesale electricity markets

© 2017 IEEE. Load-serving entities which procure electricity from the wholesale electricity market to service end-users face significant quantity and price risks due to the volatile nature of electricity demand and quasi-fixed residential tariffs at which electricity is sold. This paper investigates strategies for load serving entities to hedge against such price risks. Specifically, we compute profit-maximizing portfolios of forward contract and call options as a function of uncertain aggregate user demand and wholesale electricity prices. We compare the profit to the case of Demand Response, where users are offered monetary incentives to temporarily reduce their consumption during periods of supply shortages. Using smart meter data of residential customers in California, we simulate optimal portfolios and derive conditions under which Demand Response outperforms call options and forward contracts. Our analysis suggests that Demand Response becomes more competitive as wholesale electricity prices increase