6,636 research outputs found

    Supply Function Competition in Electricity Markets with Flexible, Inflexible, and Variable Generation

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    In this paper we study the supply function competition between power-generation firms with different levels of flexibility. Inflexible firms produce power at a constant rate over an operating horizon, while flexible firms can adjust their output to meet the fluctuations in electricity demand. Both types of firms compete in an electricity market by submitting supply functions to a system operator, who solves an optimal dispatch problem to determine the production level for each firm and the corresponding market price. We study how firms’ (in)flexibility affects their equilibrium behavior and the market price. We also analyze the impact of variable generation (such as wind and solar power) on the equilibrium, with the focus on the effects of the amount of variable generation, its priority in dispatch, and the production- based subsidies. We find that the classic supply function equilibrium model overestimates the intensity of the market competition, and even more so as more variable generation is introduced into the system. The policy of economically curtailing variable generation intensifies the market competition, reduces price volatility, and improves the system’s overall efficiency. Moreover, we show that these benefits are most significant in the absence of the production-based subsidies.http://deepblue.lib.umich.edu/bitstream/2027.42/102571/1/2014Jan28OWu.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/102571/4/1218_Wu_Apr14.pd

    Biomimetic strategies for fracture repair: engineering the cell microenvironment for directed tissue formation

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    Complications resulting from impaired fracture healing have major clinical implications on fracture management strategies. Novel concepts taken from developmental biology have driven research strategies towards the elaboration of regenerative approaches that can truly harness the complex cellular events involved in tissue formation and repair. Advances in polymer technology and a better understanding of naturally derived scaffolds have given rise to novel biomaterials with an increasing ability to recapitulate native tissue environments. This coupled with advances in the understanding of stem cell biology and technology has opened new avenues for regenerative strategies with true clinical translatability. These advances have provided the impetus to develop alternative approaches to enhance the fracture repair process. We provide an update on these advances, with a focus on the development of novel biomimetic approaches for bone regeneration and their translational potential

    Damage identification in a concrete beam using curvature difference ratio

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    Previous studies utilising changes in mode shape or curvature to locate damage rely on the fact that the greatest change occurs around the defect. However, in concrete beams this fact is undermined due to the nature of the defect as distributed multi-site cracks. In addition, differences in mode shape and curvature as ways to locate the damage is unstable because of occurrence of modal nodes and inflection points. In this paper, one interesting solution to this problem is being tested by establishing a new non-dimensional expression designated the 'Curvature Difference Ratio (CDR)'. This parameter exploits the ratio of differences in curvature of a specific mode shape for a damaged stage and another reference stage. The expression CDR is reasonably used to locate the damage and estimate the dynamic bending stiffness in a successively loaded 6m concrete beam. Results obtained by the proposed technique are tested and validated with a case study results done by Ren and De Roeck [1] also by Maeck and De Roeck [2]. Another contribution of this work is that relating changes in vibration properties to the design bending moment at beam sections as defined in Eurocode 2 specifications [3]. Linking between a beam section condition and the change in vibration data will help to give a better comprehension on the beam condition than the applied load

    How Should Justice Policy Treat Young Offenders?

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    The justice system in the United States has long recognized that juvenile offenders are not the same as adults, and has tried to incorporate those differences into law and policy. But only in recent decades have behavioral scientists and neuroscientists, along with policymakers, looked rigorously at developmental differences, seeking answers to two overarching questions: Are young offenders, purely by virtue of their immaturity, different from older individuals who commit crimes? And, if they are, how should justice policy take this into account? A growing body of research on adolescent development now confirms that teenagers are indeed inherently different from adults, not only in their behaviors, but also (and of course relatedly) in the ways their brains function. These findings have influenced a series of Supreme Court decisions relating to the treatment of adolescents, and have led legislators and other policymakers across the country to adopt a range of developmentally informed justice policies. New research is showing distinct changes in the brains of young adults, ages 18 to 21, suggesting that they too may be immature in ways that are relevant to justice policy. This knowledge brief from the MacArthur Foundation Research Network on Law and Neuroscience considers the implications of this new research

    Implementation of a drive-through testing clinic in Qatar for residents having recently returned from a country with a Covid-19 travel warning

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    © 2020 Alinier, Morris, Abu, Shaikh, Owen, licensee HBKU Press. This is an open access article distributed under the terms of the Creative Commons Attribution license CC BY 4.0, which permits unrestricted use, distribution and reproduction in any medium, provided the original work is properly cited.INTRODUCTION: The spread of the SARS-CoV-2 virus has caused chaos around the world. At the onset of the virus' detection in the State of Qatar, a free-testing system was rapidly established to invite individuals who had recently returned from countries with a COVID-19 disease travel warning to avoid putting other people at risk. The testing site needed to be accessible to individuals without requiring them to enter the hospital and congregate in a waiting area. The aim of this article is to share our experience with the early implementation of a drive-through testing clinic using the invited person's vehicle as an isolation compartment during screening to minimize person-to-person contamination. METHODS: A Hamad Medical Corporation site was selected to stage a drive-through testing facility to avoid congestion and offer space to facilitate the process. A process was rapidly agreed upon, and staff received the required training regarding infection control measures and documentation. At the testing site, individuals were subjected to the following steps: registration and history taking, temperature measurement, swabbing, and receipt of a sick leave certificate and a flyer about self-quarantine. RESULTS: Over the first six days of implementation, the relevant authorities determined that 687 individuals had to be contacted, 103 attended their testing appointment in that period, and an additional 327 people (close relations of the individuals contacted or individuals contacted but without a health card) also subjected themselves to the testing process, which took a median time of 11 minutes 39 seconds. No individual exhibited symptoms that warranted immediate isolation while they were at the drive-through testing clinic. However, four individuals were diagnosed with COVID-19 following laboratory analysis of the swab taken and followed up. The median time between swab collection and laboratory testing was 13 hours 41 minutes 59 seconds. CONCLUSIONS: Collaboration among various key health, governmental, and travel industry partners was essential to the successful and rapid implementation of a COVID-19 drive-through testing clinic in the early days of the pandemic in Qatar. The general public reacted well to this process. Communication, coordination, and planning were identified as critical factors at every step of the process. It started from the initial call to the travelers who had recently returned from a country with a newly instituted travel warning and concluded by them leaving with their sick leave certificate and an information flyer with reminders about preventative infection control measures and encouraging them to self-quarantine after having been swabbed.Peer reviewe

    Biomimetic strategies for fracture repair: engineering the cell microenvironment for directed tissue formation

    Get PDF
    Complications resulting from impaired fracture healing have major clinical implications on fracture management strategies. Novel concepts taken from developmental biology have driven research strategies towards the elaboration of regenerative approaches that can truly harness the complex cellular events involved in tissue formation and repair. Advances in polymer technology and a better understanding of naturally derived scaffolds have given rise to novel biomaterials with an increasing ability to recapitulate native tissue environments. This coupled with advances in the understanding of stem cell biology and technology has opened new avenues for regenerative strategies with true clinical translatability. These advances have provided the impetus to develop alternative approaches to enhance the fracture repair process. We provide an update on these advances, with a focus on the development of novel biomimetic approaches for bone regeneration and their translational potential

    Predicting the Knowledge: Recklessness Distinction in the Human Brain

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    Criminal convictions require proof that a prohibited act was performed in a statutorily specified mental state. Different legal consequences, including greater punishments, are mandated for those who act in a state of knowledge, compared with a state of recklessness. Existing research, however, suggests people have trouble classifying defendants as knowing, rather than reckless, even when instructed on the relevant legal criteria. We used a machine-learning technique on brain imaging data to predict, with high accuracy, which mental state our participants were in. This predictive ability depended on both the magnitude of the risks and the amount of information about those risks possessed by the participants. Our results provide neural evidence of a detectable difference in the mental state of knowledge in contrast to recklessness and suggest, as a proof of principle, the possibility of inferring from brain data in which legally relevant category a person belongs. Some potential legal implications of this result are discussed

    Test of lepton universality in beauty-quark decays

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