Abstract
Despite the large number of studies on the phenomenon of imposex, the mechanism underlying the abnormal growth of male sexual characters onto females in numerous gastropod species is yet to be fully elucidated. Although several hypotheses have been raised over the years, a convincing body of evidence indicates that tributyltin-induced imposex involves the abnormal modulation of the retinoid X receptor (RXR). Here, we investigate the RXR gene transcription at different timings and tissues upon exposure to environmentally relevant concentrations of tributyltin (TOT) (100 ng Sn/L TBT) in both genders of the imposex susceptible gastropod Nucella lapillus. RXR gene transcription was determined at two time-points (i.e., before and after imposex initiation) by quantitative Real Time PCR in potential target tissues: the central nervous system (CNS), penis/penis forming area (PFA), gonads and digestive gland. TBT-exposure altered transcription of RXR gene in a tissue and sex specific manner. In the CNS, a significant down-regulation was observed in females both before and after imposex initiation (P <= 0.01 and P <= 0.05, respectively). A similar trend was observed in male CNS at the first time-point, although differences between control and the TBT-exposed group were just above significance (P=0.059). The penis/PFA showed no differences in transcription of RXR gene between control and TBT exposed female snails before imposex induction, or before and after imposex initiation for males. However, male penis showed higher transcription of RXR gene in comparison to the PFA of females. After imposex has been induced, a significant (P <= 0.001) increase in transcription of RXR gene was observed in penis of females with vas deference sequence index (VDS) levels of 3-4 in comparison with the PFA of both control and imposex females with VDS 1-2. At advanced stages of imposex, females displayed RXR transcription patterns in penis identical to those of males, which points to a functional role of RXR in the penis of both genders. In the other tissues, gonads and digestive gland. RXR gene transcription was not affected by TBT, at any of the analysed time-points. These patterns of RXR gene transcription upon TOT exposure highlight the pivotal involvement of the CNS in the mechanism of imposex induction. We integrate the results in a conceptual model, and discuss the central role of RXR and the retinoic acid signalling pathways in imposex and male genitalia formation in gastropods.

Abstract
In this paper, Emission Controlled Security Constrained Unit Commitment (ECSCUC) model is proposed in power system. This model consists of a closed-loop modified Unit Commitment (UC) and Security-constrained Optimal Power Flow (SCOPF). An emission controlled formulation is developed to improve the economic-environment conditions of operation of power system. The objective of this ECSCUC model is to obtain the maximum social welfarebased system operating cost while maintaining the system security also considering the environmental impacts. This paper proposed a multi-stage multi-objective mixed-integer nonlinear programming (MINLP) to minimize system operation cost. In this paper, multi-reservoir cascaded hydro plant with time delay and thermal plants are considered for maintaining the demand. The presented formulation treats emission controlled security constrained unit commitment of hydrothermal power system which attempts to optimize both cost and emission simultaneously. The numerical examples exhibit the effectiveness of the proposed model in recent competitive electricity markets.

Abstract
In large scale power systems, PSS is not sufficient to damp inter-area oscillations; therefore, FACTS devices, such as SVC, which is one of the most important these devices, are typically used with PSSs. In this paper, the parameters of a power system stabiliser (PSS) and static VAR compensator (SVC) with help of a combination of a Differential Evolution algorithm (DE) and Local Search Algorithm (called the DELSA (Memetic DE algorithm)) are introduced, which are designed independently, converge to the correct and optimal solution in a small number of iterations and are attuned to damping low frequency oscillations, such as local mode oscillations, inter-area mode oscillations, other controllers modes, and modes of the generator excitation system. Suppose that the DE algorithm searches in a wide-ranging area, whereas the local search focuses on the attraction area, which probably has the optimal solution. We studied the three-area power system that was simulated in the time domain by MATLAB. © 2011 Praise Worthy Prize S.r.l. - All righs reserved.

Abstract
In this paper, economic analysis of gas-fired generator, biomass unit and wind turbine is carried out in different scenarios based on gas price, energy selling price, and load factor in Iran and the payback period and rate of return are determined. Then, the participation of the Distributed Generations (DGs) in a day-ahead energy and reserve market is simulated for scheduling from the view point of ISO. The ISO target in this model is minimizing total system producing cost considering system security constraints and technical limitation of all units. Finally, the simulation results demonstrate the reserve market as an apt place for DGs.

Abstract
This paper describes the methodology and results obtained in the studies developed for deriving loss profiles for the Portuguese electricity market. For each voltage level (LV, MV, HV and VHV) the losses were distributed by the corresponding global load diagram, proportionally to the square of the hourly consumption. Transformer losses are assigned to the consumers of voltage levels equal or smaller to the secondary voltage. Loss profiles (like load profiles) were developed for each specific year, with its calendar particularities, and the global energy balance expected for that year. A subsequent product of the adopted methodology is the set of loss factors, which are directly driven from these profiles. The methodology was developed in a project with EDP (the Portuguese distribution system operator) and the result was approved by the regulatory authority that adopted the proposed loss profiles for market use.

Abstract
Wind power forecasting is becoming an important tool in electricity markets, but the use of these forecasts in market operations and among market participants is still at an early stage. The authors discuss the current use of wind power forecasting in U.S. ISO/RTO markets, and offer recommendations for how to make efficient use of the information in state-of-the-art forecasts. © 2010 Elsevier Inc.