642 research outputs found
Managing Price Uncertainty in Prosumer-Centric Energy Trading: A Prospect-Theoretic Stackelberg Game Approach
In this paper, the problem of energy trading between smart grid prosumers,
who can simultaneously consume and produce energy, and a grid power company is
studied. The problem is formulated as a single-leader, multiple-follower
Stackelberg game between the power company and multiple prosumers. In this
game, the power company acts as a leader who determines the pricing strategy
that maximizes its profits, while the prosumers act as followers who react by
choosing the amount of energy to buy or sell so as to optimize their current
and future profits. The proposed game accounts for each prosumer's subjective
decision when faced with the uncertainty of profits, induced by the random
future price. In particular, the framing effect, from the framework of prospect
theory (PT), is used to account for each prosumer's valuation of its gains and
losses with respect to an individual utility reference point. The reference
point changes between prosumers and stems from their past experience and future
aspirations of profits. The followers' noncooperative game is shown to admit a
unique pure-strategy Nash equilibrium (NE) under classical game theory (CGT)
which is obtained using a fully distributed algorithm. The results are extended
to account for the case of PT using algorithmic solutions that can achieve an
NE under certain conditions. Simulation results show that the total grid load
varies significantly with the prosumers' reference point and their
loss-aversion level. In addition, it is shown that the power company's profits
considerably decrease when it fails to account for the prosumers' subjective
perceptions under PT
Performance comparison of different control strategies for the regulation of DC-DC negative output super-lift luo-converter
In last years, dc-dc converters solve the most issues in the industrial application in the area of power electronics, especially renewable energy, military applications and affiliated engineering developments. They are used to convert the DC input that unregulated to regulated output perhaps larger or smaller than input according to the type of converters. This paper presents three primary control method used for negative output Super lift Luo DC-DC converter. These methods include a Voltage mode control (VMC), Current mode control (CMC), and Sliding mode control (SMC). The goal of this article is to study and selected an appropriate and superior control scheme for negative DC-DC converters. The simulation results show the effectiveness of Sliding mode control for enhancing the performance of the negative dc-dc converter. Also, this method can keep the output voltage constant under load conditions. simulation results obtained by the MATLAB/Simulink environment
Constraints on stable equilibria with fluctuation-induced forces
We examine whether fluctuation-induced forces can lead to stable levitation.
First, we analyze a collection of classical objects at finite temperature that
contain fixed and mobile charges, and show that any arrangement in space is
unstable to small perturbations in position. This extends Earnshaw's theorem
for electrostatics by including thermal fluctuations of internal charges.
Quantum fluctuations of the electromagnetic field are responsible for
Casimir/van der Waals interactions. Neglecting permeabilities, we find that any
equilibrium position of items subject to such forces is also unstable if the
permittivities of all objects are higher or lower than that of the enveloping
medium; the former being the generic case for ordinary materials in vacuum.Comment: 4 pages, 1 figur
Fetomaternal outcome in sickle cell disease in a tertiary care centre
Background: Sickle cell disease is a hereditary haematological disorder prevalent in tribal regions of India. Sickle cell disease can increase complications during pregnancy and in turn negatively influence pregnancy outcomes. This study reports the analysis of tribal maternal admissions in the tertiary centre S.S.G. Hospital, Baroda, Gujarat. Hence this study was conducted to assess complications in pregnancy and maternal and perinatal outcome among women with Sickle cell disease.Methods: It was a retrospective observational study including all pregnant women with sickle cell disease after 20 weeks of gestation who delivered at S.S.G. Hospital, Baroda from August 2019 to August 2020.Results: There were 43 antenatal women with Sickle cell disease during the study period. There was increased risk of obstetric complications like gestational hypertension (11.62%), preeclampsia (9.3%), eclampsia (6.97%), HELLP syndrome (4.65%), intrauterine growth retardation (23.25%), and oligohydramnios (11.62%). Medical complications observed were mainly anaemia (53.48%), vaso-occlusive crisis (18.16%), acute chest syndrome (4.65%) and infections like urinary tract infection (6.97%) and pneumonia (4.65%). The incidence of low birth weight babies (56.94%), low APGAR score (11.62%) and neonatal ICU admissions (23.25%) was high. 6.5% cases of maternal mortality and 4.65% cases of perinatal mortality was observed.Conclusions: Pregnancy in Sickle cell disease is associated with an increased maternal morbidity and high perinatal mortality due to obstetric and medical complications
Do adolescents with impaired vision have different intentions and ambitions for their education, career and social outcomes compared to their peers? Findings from the Millennium Cohort Study
BACKGROUND/AIMS: To investigate if impaired vision adversely impacts the intentions/ambitions of adolescents concerning their future education, careers and social outcomes. METHODS: Population-based birth cohort study in the UK comprising 9273 participants from the Millennium Cohort Study who were followed up to age 17 years. Children were classified as having normal vision or unilateral or bilateral impaired vision caused by significant eye conditions based on detailed parental-structured questionnaire data on sight problems and treatment coded by clinicians. Ten domains covering education, career and social outcomes by age 30 were investigated. RESULTS: Adjusted regression models showed few differences by vision status. Bilateral impaired vision was associated with increased odds of intending to remain in full-time education after statutory school age (adjusted OR (aOR) 2.00, 95% CI 1.08 to 3.68) and of home ownership at age 30 (aOR 1.83, 95% CI 1.01 to 3.32). Impaired vision was not associated with intending to attend university. A significantly higher proportion of parents of children with bilateral or unilateral impaired vision thought that their child would not get the exam grades required to go to university than parents of those with normal vision (29% or 26% vs 16%, p=0.026). CONCLUSION: Adolescents with impaired vision have broadly the same intentions/ambitions regarding future education, careers and social outcomes as their peers with normal vision. The known significant gaps in attainment in these domains among young adults with vision impairment are therefore likely to be due to barriers that they face in achieving their ambitions. Improved implementation of existing interventions is necessary to ensure equality of opportunities
Avoidable childhood blindness in a high-income country: findings from the British Childhood Visual Impairment and Blindness Study 2
BACKGROUND/AIMS:
Addressing childhood visual disability is an international priority, with data on causes needed to plan, implement and evaluate public health and clinical care. We have examined the contribution of ‘avoidable’ blinding disorders to childhood visual impairment, severe visual impairment and blindness (VI/SVIBL) in the UK.
METHODS:
National prospective observational longitudinal study, the British Childhood Visual Impairment and Blindness Study 2 (BCVIS2), of children (aged 18 years or under) newly diagnosed with vision worse than 0.48 logMAR (logarithm of the minimum angle of resolution) or equivalent in both eyes. Proportions of children with an ‘avoidable’ disorder comprising either apotentially preventable(isolated disorders with an effective intervention which reduces disease incidence) ortreatable(isolated eye or vision disorders for which there are routinely available effective interventions able to improve vision or halt progressive visual loss) are reported.
RESULTS:
Of the 784 children within BCVIS2, isolated potentially preventable disorders were present in only 17% (132/784) and treatable disorders in an additional 13% (99/784). The most common treatable causes were cataract, retinopathy of prematurity and glaucoma. Of the 132 children with potentially preventable disease, 64 had hypoxic–ischaemic encephalopathy. Non-accidental injury accounted for almost two-thirds (11/16, 69%) of those with VI/SVIBL due to injury.
CONCLUSION:
Despite significant progress in the past decades in high-income countries, there remains a need to be vigilant about implementing preventive strategies and treatments. Attention to disorders that are currently neither preventable nor treatable remains a priority in these settings and will become increasingly important in lower-income and middle-income countries undergoing economic transition
MALDI-TOF MS: the proteomic approach, the future of fungal identification in India
Background: India, being a country where fungal infections are rampant, is urgently in need of effective tools for early and accurate diagnosis of fungal infections. Matrix-assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF-MS) is a recent method which has shown potential in identifying clinically important bacterial pathogens as well as clinically important fungi. The main objective of this study was to compare the utility of MALDI-TOF MS for the identification of fungi against that of conventional methods.Methods: The project was carried out in a tertiary care government hospital in India. Fifty clinical isolates comprising mainly various yeast species were subjected to conventional identification (Phenotypic) as well as MALDI-TOF-MS. Their results were further compared.Results: MALDI-TOF MS showed a high concordance with conventional methods while identifying species like C. albicans, C. tropicalis, C. parapsilosis and C. neoformans, although the concordance for species such as Rhodotorula and Trichosporon could only be matched up to genus level.Conclusions: MALDI-TOF MS-based identification is both a rapid and a viable tool for identification of clinically relevant yeast species with good correlation to conventional methods and a quick turnaround time
Fetomaternal outcome in pregnancy with oligohydramnios: a prospective study
Background: Oligohydramnios is defined as amniotic fluid index 30 weeks.Results: The most common risk factor associated with oligohydramnios was hypertensive disorder of pregnancy (35%) followed by intra uterine growth restriction (31%), preterm rupture of membranes (17%), post-datism (5%) and about 12% were due to idiopathic causes. Among cases majority were primigravida (43%). Lower segment caesarean section was done in 86 cases (43%), and main indication was fetal distress. There was no maternal mortality in the study. NICU admission for low birth weight (26%), pre-maturity (20%), meconium aspiration syndrome (8%), congenital anomalies (8%). Among congenital anomalies, posterior urethral valve had highest incidence (50%) followed by renal agenesis (25%). The neonatal mortality was 5%.Conclusions: Oligohydramnios adversely affects the perinatal outcome. Therefore, it requires meticulous assessment, prompt detection, timely management and treating underlying condition. However, a favourable outcome can be expected by good antenatal and intrapartum surveillance and neonatal care
Casimir force between sharp-shaped conductors
Casimir forces between conductors at the sub-micron scale cannot be ignored
in the design and operation of micro-electromechanical (MEM) devices. However,
these forces depend non-trivially on geometry, and existing formulae and
approximations cannot deal with realistic micro-machinery components with sharp
edges and tips. Here, we employ a novel approach to electromagnetic scattering,
appropriate to perfect conductors with sharp edges and tips, specifically to
wedges and cones. The interaction of these objects with a metal plate (and
among themselves) is then computed systematically by a multiple-scattering
series. For the wedge, we obtain analytical expressions for the interaction
with a plate, as functions of opening angle and tilt, which should provide a
particularly useful tool for the design of MEMs. Our result for the Casimir
interactions between conducting cones and plates applies directly to the force
on the tip of a scanning tunneling probe; the unexpectedly large temperature
dependence of the force in these configurations should attract immediate
experimental interest
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