2,116 research outputs found

    Triggering at High Luminosity Colliders

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    This article discusses the techniques used to select online promising events at high energy and high luminosity colliders. After a brief introduction, explaining some general aspects of triggering, the more specific implementation options for well established machines like the Tevatron and Large Hadron Collider are presented. An outlook on what difficulties need to be met is given when designing trigger systems at the Super Large Hadron Collider, or at the International Linear ColliderComment: Accepted for publication in New Journal of Physic

    Fukushima tritiated water release -- What is the polemic all about?

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    A mere amount of 2.2 grams (780 TBq) of tritium, diluted in 1.251061.25 \cdot 10^6 m3^3 water, contained in 1047 tanks at the Fukushima Daiichi nuclear power plant are being released to the Pacific Ocean. The operation is scheduled to last over 30 years, with not more than releasing 61 mg (22 TBq) of tritium annually. The outcry in the world's press and the world's population is huge and countries like e.g. China are protesting aloud and are even banning Japanese seafood being sold in their domestic market. The outcry is real, the perceived fears are real, the havoc created on the Japanese fish market is real, but the danger is non-existing. The panic results from over-regulations initiated by the International Commission on Radiological Protection (ICRP) and similar bodies worldwide, prohibiting a reliable assessment of dangers and are thereby also preventing a solid risk analysis of real dangers.Comment: 10 pages, 3 figure

    Influence of polarizability on metal oxide properties studied by molecular dynamics simulations

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    We have studied the dependence of metal oxide properties in molecular dynamics (MD) simulations on the polarizability of oxygen ions. We present studies of both liquid and crystalline structures of silica (SiO2), magnesia (MgO) and alumina (Al2O3). For each of the three oxides, two separately optimized sets of force fields were used: (i) Long-range Coulomb interactions between oxide and metal ions combined with a short-range pair potential. (ii) Extension of force field (i) by adding polarizability to the oxygen ions. We show that while an effective potential of type (i) without polarizable oxygen ions can describe radial distributions and lattice constants reasonably well, potentials of type (ii) are required to obtain correct values for bond angles and the equation of state. The importance of polarizability for metal oxide properties decreases with increasing temperature.Comment: 8 pages, 7 figure

    A MILP model for revenue optimization of a compressed air energy storage plant with electrolysis

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    Energy storage, both short- and long-term, will play a vital role in the energy system of the future. One storage technology that provides high power and capacity and that can be operated without carbon emissions is compressed air energy storage (CAES). However, it is widely assumed that CAES plants are not economically feasible. In this context, a mixed-integer linear programming (MILP) model of the Huntorf CAES plant was developed for revenue maximization when participating in the day-ahead market and the minute-reserve market in Germany. The plant model included various plant variations (increased power and storage capacity, recuperation) and a water electrolyzer to produce hydrogen to be used in the combustion chamber of the CAES plant. The MILP model was applied to four use cases that represent a market-orientated operation of the plant. The objective was the maximization of revenue with regard to price spreads and operating costs. To simulate forecast uncertainties of the market prices, a rolling horizon approach was implemented. The resulting revenues ranged between EUR 0.5 Mio and EUR 7 Mio per year and suggested that an economically sound operation of the storage plant is possible

    Virulence of malaria is associated with differential expression of Plasmodium falciparum var gene subgroups in a case-control study

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    Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) is a major pathogenicity factor in falciparum malaria that mediates cytoadherence. PfEMP1 is encoded by approximately 60 var genes per haploid genome. Most var genes are grouped into 3 subgroups: A, B, and C. Evidence is emerging that the specific expression of these subgroups has clinical significance. Using field samples from children from Papua New Guinea with severe, mild, and asymptomatic malaria, we compared proportions of transcripts of var groups, as determined by quantitative polymerase chain reaction. We found a significantly higher proportion of var group B transcripts in children with clinical malaria (mild and severe), whereas a large proportion of var group C transcripts was found in asymptomatic children. These data from naturally infected children clearly show that major differences exist in var gene expression between parasites causing clinical disease and those causing asymptomatic infections. Furthermore, parasites forming rosettes showed a significant up-regulation of var group A transcripts

    „Atomausstieg – was nun?“

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    Das Thema „Nutzung der Kernkraft zur Stromerzeugung“ ist stark emotional und zum Teil ideologisch besetzt, so dass der von der Bundesregierung und den Kraftwerksbetreibern im Juni 2001 vereinbarte Ausstieg heiß umstritten ist. Im Vortrag soll versucht werden, ausgehend vom derzeitigen Spannungsfeld der Elektrizitätswirtschaft, das durch die diametral entgegengesetzten Forderungen Atomausstieg und Klimaschutz sowie Nachhaltigkeit und Liberalisierung gekennzeichnet ist, aufzuzeigen, dass rezentrale regenerative und zentrale nukleare Stromerzeugung sich ergänzen könnten. Dabei fließen zentrale technische Aspekte ein, die eine von der derzeitigen politischen Linie verfolgte Dezentralisierung der Stromerzeugung zur Folge hätte. Ergänzend hierzu werden auch Forschungsergebnisse und laufende Arbeiten des IEE und des CUTEC-Institutes vorgestellt

    Parameter Optimisation of a Virtual Synchronous Machine in a Microgrid

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    Parameters of a virtual synchronous machine in a small microgrid are optimised. The dynamical behaviour of the system is simulated after a perturbation, where the system needs to return to its steady state. The cost functional evaluates the system behaviour for different parameters. This functional is minimised by Parallel Tempering. Two perturbation scenarios are investigated and the resulting optimal parameters agree with analytical predictions. Dependent on the focus of the optimisation different optima are obtained for each perturbation scenario. During the transient the system leaves the allowed voltage and frequency bands only for a short time if the perturbation is within a certain range.Comment: 17 pages, 5 figure

    Efficacy of sulfadoxine-pyrimethamine in Tanzania after two years as first-line drug for uncomplicated malaria: assessment protocol and implication for treatment policy strategies.

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    BACKGROUND\ud \ud Systematic surveillance for resistant malaria shows high level of resistance of Plasmodium falciparum to sulfadoxine-pyrimethamine (SP) across eastern and southern parts of Africa. This study assessed in vivo SP efficacy after two years of use as an interim first-line drug in Tanzania, and determined the rates of treatment failures obtained after 14 and 28 days of follow-up.\ud \ud METHODS\ud \ud The study was conducted in the Ipinda, Mlimba and Mkuranga health facilities in Tanzania. Children aged 6-59 months presenting with raised temperature associated exclusively with P. falciparum (1,000-100,000 parasites per microl) were treated with standard dose of SP. Treatment responses were classified according to the World Health Organization (WHO) definition as Adequate Clinical and Parasitological Response (ACPR), Early Treatment Failure (ETF), Late Clinical Failure (LCF) and Late Parasitological Failure (LPF) on day 14 and day 28.\ud \ud RESULTS\ud \ud Overall 196 (85.2%) of 230 patients had ACPR on day 14 but only 116 (50.9%) on day 28 (57.7% after excluding new infections by parasite genotyping). Altogether 21 (9.1%) and 13 (5.7%) of the 230 patients assessed up to day 14 and 39 (17.1%) and 55 (24.1%) of the 228 followed up to day 28 had clinical and parasitological failure, respectively.\ud \ud CONCLUSION\ud \ud These findings indicate that SP has low therapeutic value in Tanzania. The recommendation of changing first line treatment to artemether + lumefantrine combination therapy from early next year is, therefore, highly justified. These findings further stress that, for long half-life drugs such as SP, establishment of cut-off points for policy change in high transmission areas should consider both clinical and parasitological responses beyond day 14

    PCR amplification of DNA from malaria parasites on fixed and stained thick and thin blood films

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    Under some circumstances, polymerase chain reaction (PCR) amplification of deoxyribonucleic acid (DNA) from Plasmodium may become necessary from infections for which only blood slides are available. Established methods used for DNA preparation do not work in that case. We have developed a reliable and controlled method for DNA preparation from malaria parasites on fixed and stained blood films. 162 slides from 2 different locations, some stored for at least one year, have been analysed by PCR amplification of the polymorphic loci for MSA1 and MSA2. In 92% of microscopically positive slides, a PCR product could be detected using material derived from thick blood films. When thin blood films with scanty parasitaemia were used, a PCR product could be obtained with only 71% of samples. In all unsuccessful cases, DNA preparation was the limiting factor, which was controlled for by amplification of a control human templat
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