891 research outputs found

    Predictive Trading Strategy for Physical Electricity Futures

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    This article presents an original predictive strategy, based on a new mid-term forecasting model, to be used for trading physical electricity futures. The forecasting model is used to predict the average spot price, which is used to estimate the Risk Premium corresponding to electricity futures trade operations with a physical delivery. A feed-forward neural network trained with the extreme learning machine algorithm is used as the initial implementation of the forecasting model. The predictive strategy and the forecasting model only need information available from electricity derivatives and spot markets at the time of negotiation. In this paper, the predictive trading strategy has been applied successfully to the Iberian Electricity Market (MIBEL). The forecasting model was applied for the six types of maturities available for monthly futures in the MIBEL, from 1 to 6 months ahead. The forecasting model was trained with MIBEL price data corresponding to 44 months and the performances of the forecasting model and of the predictive strategy were tested with data corresponding to a further 12 months. Furthermore, a simpler forecasting model and three benchmark trading strategies are also presented and evaluated using the Risk Premium in the testing period, for comparative purposes. The results prove the advantages of the predictive strategy, even using the simpler forecasting model, which showed improvements over the conventional benchmark trading strategy, evincing an interesting hedging potential for electricity futures trading

    Restricción del crecimiento intrauterino como factor de riesgo para malformaciones congénitas

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    Indexación: ScieloAntecedentes: La restricción del crecimiento intrauterino (RCIU) se estima que estå presente en el 5% de los nacimientos y es la manifestación de procesos aberrantes que impiden el desarrollo normal del feto. Objetivos: Estimar la frecuencia de esta patología en la maternidad del Hospital Clínico de la Universidad de Chile. Obtener la tasa prevalencia al nacimiento de malformaciones congénitas (MFC) y comparar la frecuencia en recién nacidos pequeños (PEG) con los adecuados (AEG) y grandes (GEG) para la edad gestacional. Método: Se estudian todos los nacimientos, vivos y mortinatos, ocurridos entre enero de 1997 a diciembre de 2008, contenidos en la base de datos del ECLAMC (Estudio Colaborativo Latino Americano de Malformaciones Congénitas) desde 1969 a la fecha. Se excluyen los recién nacidos con malformaciones como hidrocefalia, anencefalia e hidrops, que por sus características dificultan la posibilidad de clasificación en PEG, AEG o GEG. Resultados: 10,1% de los nacimientos del período eran PEG. Entre los nacidos vivos 10% fueron PEG, mientras que 33,5% de los mortinatos eran PEG (p<0,05). Eran malformados el 12,9% de los PEG, 8,5% de los AEG y 9,3% de los GEG (p<0,05). La tasa global de malformaciones fue de 9,5%; en NV el 9,4% y en mortinatos el 33%. Conclusión: El RCIU es un factor que aumenta el riesgo de mortalidad fetal tardía y de presentar malformaciones congénitas.Background: Fetal growth restriction (FGR) is the result of anomalies that prevent the normal development of the fetus, it is present in about the 5% of births. Objectives: To estímate the frequency of FGR in the Clini-cal Hospital of the University of Chile. To estímate the congenital malformation prevalence rate at birth and compare it among small (SGE), adequate (AGE) and large (LGE) newborns according their gestational age. Methods: All live births and stillbirths included in the ECLAMC (Estudio Colaborativo Latino Americano de Malformaciones Congénitas) registered from January 1997 and December 2008 were considered. Newborns with congenital malformations that modified per se the size of the child, like hydrocephaly anencephaly and hydrops were excluded. Results: 10.1% of newborns were SGE. Among live births 10% were SGE instead of the 33.5% found in stillbirths (p<0.05). Congenital malformation rate at birth was 12.9% in SGE, 8.5% in AGE and 9.3% in LGE newborns (p<0.05). The global congenital malformation prevalence rate at birth was 9.5%; 9.4% in live newborns and 33% in stillbirth. Conclusión: The FGR increase the risk of late fetal mortality and congenital anomalies.http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-75262009000600008&nrm=is

    Long-range photoinduced charge separation in tröger bases D/A dyads

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    TrögerÂŽs base (and its derivatives) are compounds comprised of two aromatic (or polyaromatic) rings bridged by a diazocine aliphatic cycle. We report herein the photophysical properties of two series of novel TrögerÂŽs bases (TB) asymmetrically substituted by electron donor (D) and electron acceptor (A) substituents. In TB series 3, a carbonitrile group (A[dbnd]CN) lies at the position 2 of the heterocycle, while position 8 is occupied by a series of D with increasing reductant capacity: H (3a), CH3 (3b), OCH3 (3c) or N(CH3)2 (3d). A novel TB series (5a-5d) which comprise the same D, but a 2,2-dicyanovinyl group (A = CHC(CN)2) as electron acceptor, was synthesized and fully characterized. TB absorption (ÎœA max) and emission energies (ÎœF max), fluorescence quantum yields (ΊF) and emission lifetimes (τF) were determined in a series of aprotic solvents covering a wide range of medium polarity (Δ∌2-38). ÎœF max, ΊF and τF largely depend on the polarity of the medium and the nature of D/A pair. From the solvatochromic study on ÎœF max, it is concluded that upon excitation TBÂŽs develop large degrees of charge separation (CT). Photophysically, 3a-3c resembles 4-(N,N-dimethylamino)benzonitrile derivatives showing internal CT state dipole moments (ÎŒ1 *) of ∌ 15–17 D. For 3d and the entire series 5, CT occurs throughout the diazocine ring giving rise to giant ÎŒ1 * (> 25 D). This is indeed an unusual result, because it strongly suggests that the aliphatic diazocine ring can couple the D/A redox centers as a π bridge would do.Fil: Dusso, Diego. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - CĂłrdoba. Instituto de Investigaciones en FĂ­sico-quĂ­mica de CĂłrdoba. Universidad Nacional de CĂłrdoba. Facultad de Ciencias QuĂ­micas. Instituto de Investigaciones en FĂ­sico-quĂ­mica de CĂłrdoba; ArgentinaFil: Lanza Castronuovo, Priscila Ailin. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Mar del Plata. Instituto de Investigaciones En Biodiversidad y Biotecnologia. Grupo de Investigacion En Quimica Analitica y Modelado Molecular.; ArgentinaFil: Montejano, Hernan Alfredo. Universidad Nacional de RĂ­o Cuarto. Facultad de Ciencias Exactas FisicoquĂ­micas y Naturales. Instituto de Investigaciones en TecnologĂ­as EnergĂ©ticas y Materiales Avanzados. - Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - CĂłrdoba. Instituto de Investigaciones en TecnologĂ­as EnergĂ©ticas y Materiales Avanzados; ArgentinaFil: RamĂ­rez, Cristina L.. Universidad Nacional de Mar del Plata; ArgentinaFil: Parise, Alejandro Ruben. Universidad Nacional de Mar del Plata; Argentina. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - Mar del Plata; ArgentinaFil: Vera, Domingo Mariano Adolfo. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Mar del Plata. Instituto de Investigaciones En Biodiversidad y Biotecnologia. Grupo de Investigacion En Quimica Analitica y Modelado Molecular.; ArgentinaFil: Moyano, Elizabeth Laura. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - CĂłrdoba. Instituto de Investigaciones en FĂ­sico-quĂ­mica de CĂłrdoba. Universidad Nacional de CĂłrdoba. Facultad de Ciencias QuĂ­micas. Instituto de Investigaciones en FĂ­sico-quĂ­mica de CĂłrdoba; ArgentinaFil: Chesta, Carlos Alberto. Universidad Nacional de RĂ­o Cuarto. Facultad de Ciencias Exactas FisicoquĂ­micas y Naturales. Instituto de Investigaciones en TecnologĂ­as EnergĂ©ticas y Materiales Avanzados. - Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - CĂłrdoba. Instituto de Investigaciones en TecnologĂ­as EnergĂ©ticas y Materiales Avanzados; Argentin

    Multiple Sclerosis and Its Relationship with Oxidative Stress, Glutathione Redox System, ATPase System, and Membrane Fluidity

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    Multiple sclerosis (MS) is an autoimmune disease of the central nervous system (CNS) with a focus on inflammation, demyelination, and damage to axons leading to neurological deficits. MS pathology is associated with excessive reactive oxygen species (ROS) and generation of reactive nitrogen species (RNS), causing oxidative/nitrosative stress. Deregulation of glutathione homeostasis and alterations in glutathione‐dependent enzymes are implicated in MS. Reactive oxygen species enhance both monocyte adhesion and migration across brain endothelial cells. In addition, ROS can activate the expression of the nuclear transcription factor‐kappa, which upregulates the expression of many genes involved in MS, such as tumor necrosis factor‐α and nitric oxide synthase, among others, leading to mitochondrial dysfunction and energy deficits that result in mitochondrial and cellular calcium overload. Loss of mitochondrial membrane potential can increase the release of cytochrome c, one pathway that leads to neuronal apoptosis. Clinical studies suggest that omega‐3 long‐chain polyunsaturated fatty acids (PUFAs) including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have anti‐inflammatory, antioxidant, and neuroprotective effects in MS and animal models of MS. Here, we review the relationship of oxidative stress, the glutathione redox system, the ATPase system, and membrane fluidity with the development of MS. In addition, we describe the main findings of a clinical trial conducted with relapsing‐remitting MS patients who received a diet supplemented with 4 g/day of fish oil or olive oil. The effects of PUFAs supplementation on the parameters indicated above are analyzed in this work

    Megaphylogeny resolves global patterns of mushroom evolution

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    Mushroom-forming fungi (Agaricomycetes) have the greatest morphological diversity and complexity of any group of fungi. They have radiated into most niches and fulfil diverse roles in the ecosystem, including wood decomposers, pathogens or mycorrhizal mutualists. Despite the importance of mushroom-forming fungi, large-scale patterns of their evolutionary history are poorly known, in part due to the lack of a comprehensive and dated molecular phylogeny. Here, using multigene and genome-based data, we assemble a 5,284-species phylogenetic tree and infer ages and broad patterns of speciation/extinction and morphological innovation in mushroom-forming fungi. Agaricomycetes started a rapid class-wide radiation in the Jurassic, coinciding with the spread of (sub)tropical coniferous forests and a warming climate. A possible mass extinction, several clade-specific adaptive radiations and morphological diversification of fruiting bodies followed during the Cretaceous and the Paleogene, convergently giving rise to the classic toadstool morphology, with a cap, stalk and gills (pileate-stipitate morphology). This morphology is associated with increased rates of lineage diversification, suggesting it represents a key innovation in the evolution of mushroom-forming fungi. The increase in mushroom diversity started during the Mesozoic-Cenozoic radiation event, an era of humid climate when terrestrial communities dominated by gymnosperms and reptiles were also expanding.Fil: Varga, Torda. Hungarian Academy Of Sciences; HungrĂ­aFil: KrizsĂĄn, Krisztina. Hungarian Academy Of Sciences; HungrĂ­aFil: Földi, Csenge. Hungarian Academy Of Sciences; HungrĂ­aFil: Dima, BĂĄlint. Eötvös LorĂĄnd University; HungrĂ­aFil: SĂĄnchez-GarcĂ­a, Marisol. Clark University; Estados UnidosFil: Lechner, Bernardo Ernesto. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Ciudad Universitaria. Instituto de MicologĂ­a y BotĂĄnica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de MicologĂ­a y BotĂĄnica; ArgentinaFil: SĂĄnchez-RamĂ­rez, Santiago. University of Toronto; CanadĂĄFil: Szöllosi, Gergely J.. Eötvös LorĂĄnd University; HungrĂ­aFil: SzarkĂĄndi, JĂĄnos G.. University Of Szeged; HungrĂ­aFil: Papp, Viktor. Szent IstvĂĄn University; HungrĂ­aFil: Albert, LĂĄszlĂł. Hungarian Mycological Society; HungrĂ­aFil: Andreopoulos, William. United States Department Of Energy. Joint Genome Institute; Estados UnidosFil: Angelini, Claudio. Jardin Botanico Nacional Ma. Moscoso; RepĂșblica DominicanaFil: AntonĂ­n, VladimĂ­r. Moravian Museum; RepĂșblica ChecaFil: Barry, Kerrie W.. United States Department Of Energy. Joint Genome Institute; Estados UnidosFil: Bougher, Neale L.. Western Australian Herbarium; AustraliaFil: Buchanan, Peter. Manaaki Whenua-landcare Research; Nueva ZelandaFil: Buyck, Bart. MusĂ©um National d'Histoire Naturelle; FranciaFil: Bense, ViktĂłria. Hungarian Academy Of Sciences; HungrĂ­aFil: Catcheside, Pam. State Herbarium Of South Australia; AustraliaFil: Chovatia, Mansi. United States Department Of Energy. Joint Genome Institute; Estados UnidosFil: Cooper, Jerry. Manaaki Whenua-landcare Research; Nueva ZelandaFil: DĂ€mon, Wolfgang. Oberfeldstrasse 9; AustriaFil: Desjardin, Dennis. San Francisco State University; Estados UnidosFil: Finy, PĂ©ter. Zsombolyai U. 56.; HungrĂ­aFil: Geml, JĂłzsef. Naturalis Biodiversity Center; PaĂ­ses BajosFil: Haridas, Sajeet. United States Department Of Energy. Joint Genome Institute; Estados UnidosFil: Hughes, Karen. University of Tennessee; Estados UnidosFil: Justo, Alfredo. Clark University; Estados UnidosFil: Karasinski, Dariusz. Polish Academy of Sciences; Poloni

    Sperm from Hyh Mice Carrying a Point Mutation in αSNAP Have a Defect in Acrosome Reaction

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    Hydrocephalus with hop gait (hyh) is a recessive inheritable disease that arose spontaneously in a mouse strain. A missense mutation in the Napa gene that results in the substitution of a methionine for isoleucine at position 105 (M105I) of αSNAP has been detected in these animals. αSNAP is a ubiquitous protein that plays a key role in membrane fusion and exocytosis. In this study, we found that male hyh mice with a mild phenotype produced morphologically normal and motile sperm, but had a strongly reduced fertility. When stimulated with progesterone or A23187 (a calcium ionophore), sperm from these animals had a defective acrosome reaction. It has been reported that the M105I mutation affects the expression but not the function of the protein. Consistent with an hypomorphic phenotype, the testes and epididymides of hyh mice had low amounts of the mutated protein. In contrast, sperm had αSNAP levels indistinguishable from those found in wild type cells, suggesting that the mutated protein is not fully functional for acrosomal exocytosis. Corroborating this possibility, addition of recombinant wild type αSNAP rescued exocytosis in streptolysin O-permeabilized sperm, while the mutant protein was ineffective. Moreover, addition of recombinant αSNAP. M105I inhibited acrosomal exocytosis in permeabilized human and wild type mouse sperm. We conclude that the M105I mutation affects the expression and also the function of αSNAP, and that a fully functional αSNAP is necessary for acrosomal exocytosis, a key event in fertilization

    Epidemiology of Invasive Fungal Infections in Latin America

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    The pathogenic role of invasive fungal infections (IFIs) has increased during the past two decades in Latin America and worldwide, and the number of patients at risk has risen dramatically. Working habits and leisure activities have also been a focus of attention by public health officials, as endemic mycoses have provoked a number of outbreaks. An extensive search of medical literature from Latin America suggests that the incidence of IFIs from both endemic and opportunistic fungi has increased. The increase in endemic mycoses is probably related to population changes (migration, tourism, and increased population growth), whereas the increase in opportunistic mycoses may be associated with the greater number of people at risk. In both cases, the early and appropriate use of diagnostic procedures has improved diagnosis and outcome

    Multiomics integrative analysis identifies APOE allele-specific blood biomarkers associated to Alzheimer's disease etiopathogenesis

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    Alzheimer’s disease (AD) is the most common form of dementia, currently affecting 35 million people worldwide. Apolipoprotein E (APOE) Δ4 allele is the major risk factor for sporadic, late-onset AD (LOAD), which comprises over 95% of AD cases, increasing the risk of AD 4-12 fold. Despite this, the role of APOE in AD pathogenesis is still a mystery. Aiming for a better understanding of APOE-specific effects, the ADAPTED consortium analysed and integrated publicly available data of multiple OMICS technologies from both plasma and brain stratified by APOE haplotype (APOE2, APOE3 and APOE4). Combining genome-wide association studies (GWAS) with differential mRNA and protein expression analyses and single-nuclei transcriptomics, we identified genes and pathways contributing to AD in both APOE dependent and independent fashion. Interestingly, we characterised a set of biomarkers showing plasma and brain consistent protein profiles and opposite trends in APOE2 and APOE4 AD cases that could constitute screening tools for a disease that lacks specific blood biomarkers. Beside the identification of APOE-specific signatures, our findings advocate that this novel approach, based on the concordance across OMIC layers and tissues, is an effective strategy for overcoming the limitations of often underpowered single-OMICS studies
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