Base-load cycling on a system with significant wind penetration

Certain developments in the electricity sector may result in suboptimal operation of base-load generating units in countries worldwide. Despite the fact they were not designed to operate in a flexible manner, increasing penetration of variable power sources coupled with the deregulation of the electricity sector could lead to these base-load units being shut down or operated at part-load levels more often. This cycling operation would have onerous effects on the components of these units and potentially lead to increased outages and significant costs. This paper shows the serious impact increasing levels of wind power will have on the operation of base-load units. Those base-load units which are not large contributors of primary reserve to the system and have relatively shorter start-up times were found to be the most impacted as wind penetration increases. A sensitivity analysis shows the presence of storage or interconnection on a power system actually exacerbates base-load cycling until very high levels of wind power are reached. Finally, it is shown that if the total cycling costs of the individual base-load units are taken into consideration in the scheduling model, subsequent cycling operation can be reduced.Thermal Power Generation; Wind Power Generation; Pumped Storage Power Generation; Interconnected Power Systems; Power System Modeling; Costs

Unit commitment for systems with significant wind penetration

The stochastic nature of wind alters the unit commitment and dispatch problem. By accounting for this uncertainty when scheduling the system, more robust schedules are produced, which should, on average, reduce expected costs. In this paper, the effects of stochastic wind and load on the unit commitment and dispatch of power systems with high levels of wind power are examined. By comparing the costs, planned operation and performance of the schedules produced, it is shown that stochastic optimization results in less costly, of the order of 0.25%, and better performing schedules than deterministic optimization. The impact of planning the system more frequently to account for updated wind and load forecasts is then examined. More frequent planning means more up to date forecasts are used, which reduces the need for reserve and increases performance of the schedules. It is shown that mid merit and peaking units and the interconnection are the most affected parts of the system where uncertainty of wind is concernedpower generation dispatch; power system economics; stochastic systems; wind power generation

Do prerecorded lecture VODcasts affect lecture attendance of first-year pre-clinical Graduate Entry to Medicine students?

Background: There is increasing concern amongst educators that the provision of recorded lectures may reduce student attendance of live lectures. We therefore sought to determine if the provision of prerecorded lecture video podcasts (VODcasts) to first-year Graduate Entry to Medicine (GEM) students, affected attendance at 21 Physiology lectures within three separate pre-clinical modules.: Methods: Data on lecture attendance, utilization of VODcasts, and whether VODcasts should replace live lectures were drawn from three surveys conducted in academic years 2014–2015 and 2015–2016 on all first-year GEM students in two first-year pre-clinical modules where prerecorded Physiology VODcasts were available for viewing or downloading prior to scheduled live lectures. Results: A total of 191/214 (89%) students responded to the three surveys, with 84.3% of students attending all 21 lectures in the study. Only 4% of students missed more than one lecture in each of the three lecture series, with 79% indicating that VODcasts should not replace lectures. Conclusion: Therefore, we conclude that the attendance of pre-clinical GEM students at live lectures is not significantly impacted upon by the provision of lecture VODcasts, with most students viewing them as useful revision tools rather than as a replacement for live lectures

Optimal interconnection and renewable targets in North-West Europe. ESRI WP416, December 2011

We present a mixed-integer, linear programming model for determining optimal interconnection locations using a cost minimisation approach. Optimal interconnection and capacity investment decisions are determined under various targets for renewable penetration. The model is applied to a test system for eight countries in Northern Europe. It is found that considerations on the supply side dominate demand side considerations when determining optimal interconnection investment. Interconnection is found to be most valuable when targets for renewable electricity are set for the whole system, rather than for different regions within the system

The effect of Demand Response and wind generation on electricity investment and operation. ESRI WP577, December 2017

We present a novel method of determining the contribution of load-shifting Demand Response (DR) to energy and reserve markets. We model DR in an Mixed Complementarity Problem (MCP) framework with high levels of wind penetration. Investment, exit and operational decisions are optimised simultaneously. We examine the potential for DR to participate in both energy and reserve markets. DR participation in the energy market reduces costs and prices but the impact of DR participation in reserve markets is limited. DR and wind generation are strongly complementary, due to the ability of DR to mitigate against the variability of wind generation, with the highest impacts of DR seen at high levels of wind penetration. DR participation in the energy market gives rise to lower equilibrium levels of investment in conventional generation and induces a Pareto improvement versus a market with no DR participation. The total impact of DR is highly dependent on specific system characteristics

Optimal interconnection and renewable targets in North-West Europe

We present a mixed-integer, linear programming model for determining optimal interconnection locations using a cost minimisation approach. Optimal interconnection and capacity investment decisions are determined under various targets for renewable penetration. The model is applied to a test system for eight countries in Northern Europe. It is found that considerations on the supply side dominate demand side considerations when determining optimal interconnection investment. Interconnection is found to be most valuable when targets for renewable electricity are set for the whole system, rather than for different regions within the system

Homeobox gene Rhox5 is regulated by epigenetic mechanisms in cancer and stem cells and promotes cancer growth

<p>Abstract</p> <p>Background</p> <p>Homeobox genes murine <it>Rhox5 </it>and human <it>RHOXF1 </it>are expressed in early embryonic stages and then mostly restricted to germline tissues in normal adult, yet they are aberrantly expressed in cancer cells <it>in vitro </it>and <it>in vivo </it>. Here we study the epigenetic regulation and potential functions of <it>Rhox5 </it>gene.</p> <p>Findings</p> <p>In <it>Rhox5 </it>-silenced or extremely low expresser cells, we observed low levels of active histone epigenetic marks (H3ac, H4ac and H3K4me2) and high levels of repressive mark H3K9me2 along with DNA hypermethylation in the promoter. In <it>Rhox5 </it>low expresser cells, we typically observed modest levels of both active and repressive histone marks along with moderate DNA methylation. In <it>Rhox5 </it>highly expressed CT26 cancer cells, we observed DNA hypomethylation along with high levels of both active and repressive histone marks. Epigenetic drugs (retinoic acid and MS-275) induced F9 cell differentiation with enhanced <it>Rhox5 </it>expression and dynamic changes of epigenetic marks. Finally, <it>Rhox5 </it>knockdown by small hairpin RNA (shRNA) in CT26 colon cancer decreased cell proliferation and migration <it>in vitro </it>and tumor growth <it>in vivo </it>.</p> <p>Conclusions</p> <p>Both DNA methylation and histone methylation/acetylation play key roles in modulating <it>Rhox5 </it>expression in various cell types. The stem cell-like "bivalent domain", an epigenetic feature originally identified in key differentiation genes within stem cells, exists in the <it>Rhox5 </it>gene promoter in not only embryonic stem cells but also cancer cells, cancer stem cells, and differentiated Sertoli cells. As <it>Ras </it>signaling-dependent <it>Rhox5 </it>expression promotes tumor growth, <it>Rhox5 </it>may be an ideal target for therapeutic intervention in cancer.</p

Using an online student response system, Socrative, to facilitate active learning of Physiology by first year graduate entry to medicine students: a feasibility study

Technologies such as audience response units (‘clickers’) have been used to facilitate greater student engagement within a variety of educational settings, but numerous technical issues have limited their more widespread use. More recently, flexible, cloud-based student response systems (SRSs), which are designed for use with student mobile devices and overcome most of the limitations of clicker systems, have become widely available. However, the suitability of use for such systems in accelerated degree programmes such as graduate entry to medicine (GEM) has yet to be assessed. Therefore, we utilised Socrative, a freely available SRS, in a physiology component of a first year GEM module to ascertain, a) its ease of deployment, b) its popularity with students and, c) if they felt it improved their learning. There were no technical problems using Socrative. Further, 93% of respondents to an attitudinal survey strongly agreed or agreed that they favoured using Socrative in the classroom, and that they felt that it had improved their learning (92%). Thus, our data strongly indicate that the use of SRSs like Socrative would be highly valued even by the time-pressured, relatively mature students enrolled on accelerated professional courses such as GEM