481 research outputs found

    A bootstrap-based method to achieve optimality on estimating the extreme-value index

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    Estimators of the extreme-value index are based on a set of upper order statistics. We present an adaptive method to choose the number of order statistics involved in an optimal way, balancing variance and bias components. Recently this has been achieved for the similar but somewhat less involved case of regularly varying tails (Drees and Kaufmann(1997); Danielsson et al.(1996)). The present paper follows the line of proof of the last mentioned paper

    Optimized Configuration of Diesel Engine-Fuel Cell-Battery Hybrid Power Systems in a Platform Supply Vessel to Reduce CO<sub>2</sub> Emissions

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    The main objective of this paper is to select the optimal configuration of a ship&rsquo;s power system, considering the use of fuel cells and batteries, that would achieve the lowest CO2 emissions also taking into consideration the number of battery cycles. The ship analyzed in this work is a Platform Supply Vessel (PSV) used to support oil and gas offshore platforms transporting goods, equipment, and personnel. The proposed scheme considers the ship&rsquo;s retrofitting. The ship&rsquo;s original main generators are maintained, and the fuel cell and batteries are installed as complementary sources. Moreover, a sensitivity analysis is pursued on the ship&rsquo;s demand curve. The simulations used to calculate the CO2 emissions for each of the new hybrid configurations were developed using HOMER software. The proposed solutions are auxiliary generators, three types of batteries, and a proton-exchange membrane fuel cell (PEMFC) with different sizes of hydrogen tanks. The PEMFC and batteries were sized as containerized solutions, and the sizing of the auxiliary engines was based on previous works. Each configuration consists of a combination of these solutions. The selection of the best configuration is one contribution of this paper. The new configurations are classified according to the reduction of CO2 emitted in comparison to the original system. For different demand levels, the results indicate that the configuration classification may vary. Another valuable contribution of this work is the sizing of the battery and hydrogen storage systems. They were installed in 20 ft containers, since the installation of batteries, fuel cells and hydrogen tanks in containers is widely used for ship retrofit. As a result, the most significant reduction of CO2 emissions is 10.69%. This is achieved when the configuration includes main generators, auxiliary generators, a 3,119 kW lithium nickel manganese cobalt (LNMC) battery, a 250 kW PEMFC, and 581 kg of stored hydrogen

    Variability in an effector gene promoter of a necrotrophic fungal pathogen dictates epistasis and effector-triggered susceptibility in wheat

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    The fungus Parastagonospora nodorum uses proteinaceous necrotrophic effectors (NEs) to induce tissue necrosis on wheat leaves during infection, leading to the symptoms of septoria nodorum blotch (SNB). The NEs Tox1 and Tox3 induce necrosis on wheat possessing the dominant susceptibility genes Snn1 and Snn3B1/Snn3D1, respectively. We previously observed that Tox1 is epistatic to the expression of Tox3 and a quantitative trait locus (QTL) on chromosome 2A that contributes to SNB resistance/susceptibility. The expression of Tox1 is significantly higher in the Australian strain SN15 compared to the American strain SN4. Inspection of the Tox1 promoter region revealed a 401 bp promoter genetic element in SN4 positioned 267 bp upstream of the start codon that is absent in SN15, called PE401. Analysis of the world-wide P. nodorum population revealed that a high proportion of Northern Hemisphere isolates possess PE401 whereas the opposite was observed in representative P. nodorum isolates from Australia and South Africa. The presence of PE401 removed the epistatic effect of Tox1 on the contribution of the SNB 2A QTL but not Tox3. PE401 was introduced into the Tox1 promoter regulatory region in SN15 to test for direct regulatory roles. Tox1 expression was markedly reduced in the presence of PE401. This suggests a repressor molecule(s) binds PE401 and inhibits Tox1 transcription. Infection assays also demonstrated that P. nodorum which lacks PE401 is more pathogenic on Snn1 wheat varieties than P. nodorum carrying PE401. An infection competition assay between P. nodorum isogenic strains with and without PE401 indicated that the higher Tox1-expressing strain rescued the reduced virulence of the lower Tox1-expressing strain on Snn1 wheat. Our study demonstrated that Tox1 exhibits both ‘selfish’ and ‘altruistic’ characteristics. This offers an insight into a complex NE-NE interaction that is occurring within the P. nodorum population. The importance of PE401 in breeding for SNB resistance in wheat is discussed

    Safflower oil: an integrated assessment of phytochemistry, antiulcerogenic activity, and rodent and environmental toxicity

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    Gastric ulcers are a significant medical problem and the development of complications lead to significant mortality rates worldwide. In Brazil, Carthamus tinctorius L., Asteraceae, seeds essential oil, the safflower oil, is currently used as a thermogenic compound and as treatment for problems related to the cardiovascular system. In this study, by Raman spectroscopy, it was shown that oleic and linoleic acids are the compounds present in higher concentrations in the safflower oil. We demonstrated that safflower oil (750 mg/kg, p.o.) decrease the ulcerogenic lesions in mice after the administration of hydrochloric acid-ethanol. The gastric ulcers induced by non-steroidal anti-inflammatory drug (NSAID) in mice treated with cholinomimetics were treated with four different doses of safflower oil, of which, the dose of 187.5 mg/kg (p.o.) showed significant antiulcerogenic properties (**p < 0.01). Moreover, the safflower oil at doses of 187.5 mg/kg (i.d.) increased the pH levels, gastric volume (**p < 0.01) and gastric mucus production (***p < 0.001), and decreased the total gastric acid secretion (***p < 0.001). The acute toxicity tests showed that safflower oil (5.000 mg/kg, p.o.) had no effect on mortality or any other physiological parameter. Ecotoxicological tests performed using Daphnia similis showed an EC50 at 223.17 mg/l, and therefore safflower oil can be considered “non-toxic” based on the directive 93/67/EEC on risk assessment for new notified substances by European legislation. These results indicate that the antiulcer activity of Safflower oil may be due to cytoprotective effects, which serve as support for new scientific studies related to this pathology.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Universidade Santa Cecília Programa de Pós-graduação em Sustentabilidade de Ecossistemas Costeiros e Marinhos Laboratório de Pesquisa em Produtos NaturaisUniversidade Estadual de Campinas Departamento de Fisiologia e Biofísica Laboratório de Produtos NaturaisUniversidade Santa Cecília Laboratório de EcotoxicologiaUniversidade Federal de São Paulo (UNIFESP) Instituto do MarUniversidade Camilo Castelo Branco Instituto de Engenharia BiomédicaUNIFESP, Instituto do MarFAPESP: 2009/01788-5SciEL

    New Results for the Correlation Functions of the Ising Model and the Transverse Ising Chain

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    In this paper we show how an infinite system of coupled Toda-type nonlinear differential equations derived by one of us can be used efficiently to calculate the time-dependent pair-correlations in the Ising chain in a transverse field. The results are seen to match extremely well long large-time asymptotic expansions newly derived here. For our initial conditions we use new long asymptotic expansions for the equal-time pair correlation functions of the transverse Ising chain, extending an old result of T.T. Wu for the 2d Ising model. Using this one can also study the equal-time wavevector-dependent correlation function of the quantum chain, a.k.a. the q-dependent diagonal susceptibility in the 2d Ising model, in great detail with very little computational effort.Comment: LaTeX 2e, 31 pages, 8 figures (16 eps files). vs2: Two references added and minor changes of style. vs3: Corrections made and reference adde

    A joint physics and radiobiology DREAM team vision - Towards better response prediction models to advance radiotherapy.

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    Radiotherapy developed empirically through experience balancing tumour control and normal tissue toxicities. Early simple mathematical models formalized this practical knowledge and enabled effective cancer treatment to date. Remarkable advances in technology, computing, and experimental biology now create opportunities to incorporate this knowledge into enhanced computational models. The ESTRO DREAM (Dose Response, Experiment, Analysis, Modelling) workshop brought together experts across disciplines to pursue the vision of personalized radiotherapy for optimal outcomes through advanced modelling. The ultimate vision is leveraging quantitative models dynamically during therapy to ultimately achieve truly adaptive and biologically guided radiotherapy at the population as well as individual patient-based levels. This requires the generation of models that inform response-based adaptations, individually optimized delivery and enable biological monitoring to provide decision support to clinicians. The goal is expanding to models that can drive the realization of personalized therapy for optimal outcomes. This position paper provides their propositions that describe how innovations in biology, physics, mathematics, and data science including AI could inform models and improve predictions. It consolidates the DREAM team's consensus on scientific priorities and organizational requirements. Scientifically, it stresses the need for rigorous, multifaceted model development, comprehensive validation and clinical applicability and significance. Organizationally, it reinforces the prerequisites of interdisciplinary research and collaboration between physicians, medical physicists, radiobiologists, and computational scientists throughout model development. Solely by a shared understanding of clinical needs, biological mechanisms, and computational methods, more informed models can be created. Future research environment and support must facilitate this integrative method of operation across multiple disciplines

    Usefulness of NGS for diagnosis of dominant beta-thalassemia and unstable hemoglobinopathies in five clinical cases

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    Unstable hemoglobinopathies (UHs) are rare anemia disorders (RADs) characterized by abnormal hemoglobin (Hb) variants with decreased stability. UHs are therefore easily precipitating, causing hemolysis and, in some cases, leading to dominant beta-thalassemia (dBTHAL). The clinical picture of UHs is highly heterogeneous, inheritance pattern is dominant, instead of recessive as in more prevalent major Hb syndromes, and may occur de novo. Most cases of UHs are not detected by conventional testing, therefore diagnosis requires a high index of suspicion of the treating physician. Here, we highlight the importance of next generation sequencing (NGS) methodologies for the diagnosis of patients with dBTHAL and other less severe UH variants. We present five unrelated clinical cases referred with chronic hemolytic anemia, three of them with severe blood transfusion dependent anemia. Targeted NGS analysis was performed in three cases while whole exome sequencing (WES) analysis was performed in two cases. Five different UH variants were identified correlating with patients' clinical manifestations. Four variants were related to the beta-globin gene (Hb Bristol-Alesha, Hb Debrousse, Hb Zunyi, and the novel Hb Mokum) meanwhile one case was caused by a mutation in the alpha-globin gene leading to Hb Evans. Inclusion of alpha and beta-globin genes in routine NGS approaches for RADs has to be considered to improve diagnosis' efficiency of RAD due to UHs. Reducing misdiagnoses and underdiagnoses of UH variants, especially of the severe forms leading to dBTHAL would also facilitate the early start of intensive or curative treatments for these patients.Genetics of disease, diagnosis and treatmen
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