128 research outputs found

    Threshold volatility models: forecasting performance

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    The aim of this paper is to compare the forecasting performance of competing volatility models, in order to capture the asymmetric effect in the volatility. We focus on examining the relative out-of-sample forecasting ability of the models (SETAR-TGARCH and SETAR-THSV), which contain the introduction of regimes based on thresholds in the mean equation and volatility equation, compared to the GARCH model and SV model. For each model, we consider two cases: Gaussian and t-Student measurement noise distribution. An important problem when evaluating the predictive ability of volatility models is that the “true” underlying process is not observable and thus a proxy must be defined for the unobservable volatility. To attain our proposal, the proxy volatility measure and the loss function must also be decided to ensure a correct ranking of models. Our empirical application suggests the following results: when time series include leverage effects on the mean, the introduction of threshold in the mean and variance equations produces more accurate predictions. If the leverage in the mean is not important, then the SVt is flexible enough to beat the threshold models.Peer ReviewedPostprint (published version

    IRF3 regulates neuroinflammatory responses and the expression of genes associated with Alzheimer's disease.

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    The pathological role of interferon signaling is emerging in neuroinflammatory disorders, yet, the specific role of Interferon Regulatory Factor 3 (IRF3) in neuroinflammation remains poorly understood. Here, we show that global IRF3 deficiency delays TLR4-mediated signaling in microglia and attenuates the hallmark features of LPS-induced inflammation such as cytokine release, microglial reactivity, astrocyte activation, myeloid cell infiltration, and inflammasome activation. Moreover, expression of a constitutively active IRF3 (S388D/S390D:IRF3-2D) in microglia induces a transcriptional program reminiscent of the Activated Response Microglia and the expression of genes associated with Alzheimer's Disease, notably apolipoprotein-e. Lastly, using bulk-RNAseq of IRF3-2D brain myeloid cells, we identified Z-DNA binding protein-1 as a target of IRF3 that is relevant across various neuroinflammatory disorders. Together, our results identify IRF3 as an important regulator of LPS-mediated neuroinflammatory responses and highlight IRF3 as a central regulator of disease-specific gene activation in different neuroinflammatory diseases

    Interventions to improve perinatal outcomes among migrant women in high-income countries: a systematic review protocol

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    INTRODUCTION: Women who are migrants and who are pregnant or postpartum are at high risk of poorer perinatal outcomes compared with host country populations due to experiencing numerous additional stressors including social exclusion and language barriers. High-income countries (HICs) host many migrants, including forced migrants who may face additional challenges in the peripartum period. Although HICs' maternity care systems are often well developed, they are not routinely tailored to the needs of migrant women. The primary objective will be to determine what interventions exist to improve perinatal outcomes for migrant women in HICs. The secondary objective will be to explore the effectiveness of these interventions by exploring the impact on perinatal outcomes. The main outcomes of interest will be rates of preterm birth, birth weight, and number of antenatal or postnatal appointments attended. METHODS AND ANALYSIS: This protocol follows the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Protocols guidelines. EMBASE, EMCARE, MEDLINE and PsycINFO, CENTRAL, Scopus, CINAHL Plus, and Web of Science, as well as grey literature sources will be searched from inception up to December 2022. We will include randomised controlled trials, quasi-experimental and interventional studies of interventions, which aim to improve perinatal outcomes in any HIC. There will be no language restrictions. We will exclude studies presenting only qualitative outcomes and those including mixed populations of migrant and non-migrant women. Screening and data extraction will be completed by two independent reviewers and risk of bias will be assessed using the Quality Assessment Tool for Quantitative Studies. If a collection of suitably comparable outcomes is retrieved, we will perform meta-analysis applying a random effects model. Presentation of results will comply with guidelines in the Cochrane Handbook of Systematic Reviews of Interventions and the PRISMA statement. ETHICS AND DISSEMINATION: Ethical approval is not required. Results will be submitted for peer-reviewed publication and presented at national and international conferences. The findings will inform the work of the Lancet Migration European Hub. PROSPERO REGISTRATION NUMBER: CRD42022380678

    Wnt evolution and function shuffling in liberal and conservative chordate genomes

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    Background What impact gene loss has on the evolution of developmental processes, and how function shuffling has affected retained genes driving essential biological processes, remain open questions in the fields of genome evolution and EvoDevo. To investigate these problems, we have analyzed the evolution of the Wnt ligand repertoire in the chordate phylum as a case study. Results We conduct an exhaustive survey of Wnt genes in genomic databases, identifying 156 Wnt genes in 13 non-vertebrate chordates. This represents the most complete Wnt gene catalog of the chordate subphyla and has allowed us to resolve previous ambiguities about the orthology of many Wnt genes, including the identification of WntA for the first time in chordates. Moreover, we create the first complete expression atlas for the Wnt family during amphioxus development, providing a useful resource to investigate the evolution of Wnt expression throughout the radiation of chordates. Conclusions Our data underscore extraordinary genomic stasis in cephalochordates, which contrasts with the liberal and dynamic evolutionary patterns of gene loss and duplication in urochordate genomes. Our analysis has allowed us to infer ancestral Wnt functions shared among all chordates, several cases of function shuffling among Wnt paralogs, as well as unique expression domains for Wnt genes that likely reflect functional innovations in each chordate lineage. Finally, we propose a potential relationship between the evolution of WntA and the evolution of the mouth in chordates

    From laboratory to industrial storage - Translating volatile organic compounds into markers for assessing garlic storage quality

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    Garlic (Allium sativum L.) has long been grown for its culinary and health-promoting qualities. The seasonal nature of garlic cropping requires that bulbs be stored for many months after harvest to ensure a year-round supply. During this time, quality is known to deteriorate, and efforts have been made to improve the longevity of stored bulbs. Cold temperatures within the stores prolong shelf life, but fine temperature control is needed to avoid freezing damage or cold induced stress. Here, quality traits (alliinase activity, firmness, and water content) are measured in response to a 96 h − 5 °C cold stress, to simulate the effect of non-isothermic temperature control in a − 1.5 °C warehouse. Volatile organic compounds (VOCs) are measured by thermal desorption gas chromatography time of flight mass spectrometry to identify markers of non-isothermic storage in garlic. 129 compounds were putatively identified and four (L-lactic acid, 2,6-dimethylhetpadecane, 4-methyldodecane, and methylcyclopentane) showed high predictive accuracy for cold stress. VOCs were also sampled directly from a cold storage facility and the whole profile discriminated between sampling time points. Five VOCS were highly predictive for storage time in the warehouse but were different to VOCs previously shown to discriminate between storage times in a laboratory setting. This indicates the need for realistic warehouse experiments to test quality markers

    Is Thigh Flow Injection Through Central Catheters Safe for Tomographic Studies?

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    Objetivo: Demostrar la seguridad de la inyecciĂłn mecĂĄnica de contraste a travĂ©s de catĂ©teres centrales, excluyendo catĂ©teres de hemodiĂĄlisis y puertos de quimioterapia, a velocidades > 3 ml/seg. MĂ©todos: Se realizĂł un estudio descriptivo, longitudinal y prospectivo en pacientes hospitalizados, quienes tenĂ­an como Ășnica vĂ­a de acceso una lĂ­nea central y en quienes se les realizĂł inyecciĂłn mecĂĄnica de medio de contraste a una velocidad de 3 y 4 cm3/seg. Se evaluaron las complicaciones hemodinĂĄmicas y relacionadas con la integridad de los catĂ©teres. Resultados: Se inyectaron 20 pacientes a travĂ©s de catĂ©teres venosos centrales (CVC) y 35 pacientes a travĂ©s de catĂ©teres centrales de inserciĂłn perifĂ©rica (CCIP). No se presentaron complicaciones hemodinĂĄmicas ni se observaron complicaciones relacionadas con la integridad del catĂ©ter. ConclusiĂłn: La inyecciĂłn mecĂĄnica de medio de contraste a travĂ©s de CVC y CCIP, utilizando velocidades entre 3 y 4,5 ml/seg es una alternativa segura y viable para tomografĂ­as contrastadas.ArtĂ­culo original3865-3868Objective: The objective is to demonstrate the safety of medium contrast mechanical injection through central lines, not through a hemotherapy port or a hemodialysis catherer, at rates > 3 ml/sec. Methods: We performed a descriptive, longitudinal and prospective injection in patients who had a central line as the only venous access, and who underwent a mechanical injection with medium contrast at a rate 3-4 cc / sec. We evaluated complications in hemodynamics and complications related to the integrity of catherers. Results: 20 patients were injected via central venous catheters (CVC) and 35 patients via peripherally inserted central catheters (PICC). No complications were observed related to the integrity of the catherer. Conclusion: Medium contrast mechanical injection, performed through CVC and PICC at rates between 3 and 4.5 ml / sec, is considered a safe and viable alternative to contrast-enhanced CT

    Low energy consequences from supersymmetric models with left-right symmetry

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    We consider several low energy consequences arising from a class of supersymmetric models based on the gauge groups SU(2)L×SU(2)R×U(1)B−LSU(2)_L\times SU(2)_R \times U(1)_{B-L} and SU(4)C×SU(2)L×SU(2)RSU(4)_C\times SU(2)_L \times SU(2)_R in which the gauge hierarchy and ÎŒ\mu problems have been resolved. There are important constraints on the MSSM parameters tan⁥ÎČ(≃mt/mb)\tan \beta (\simeq m_t/m_b), BB and ÎŒ\mu, and we discuss how they are reconciled with radiative electroweak breaking. We also consider the ensuing sparticle and Higgs spectroscopy, as well as the decays b→sÎłb\to s \gamma and Ό→eÎł\mu \to e \gamma. The latter process may be amenable to experimental tests through an order of magnitude increase in sensitivity.Comment: 17 pages, latex2

    Search for muon-neutrino emission from GeV and TeV gamma-ray flaring blazars using five years of data of the ANTARES telescope

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    The ANTARES telescope is well-suited for detecting astrophysical transient neutrino sources as it can observe a full hemisphere of the sky at all times with a high duty cycle. The background due to atmospheric particles can be drastically reduced, and the point-source sensitivity improved, by selecting a narrow time window around possible neutrino production periods. Blazars, being radio-loud active galactic nuclei with their jets pointing almost directly towards the observer, are particularly attractive potential neutrino point sources, since they are among the most likely sources of the very high-energy cosmic rays. Neutrinos and gamma rays may be produced in hadronic interactions with the surrounding medium. Moreover, blazars generally show high time variability in their light curves at different wavelengths and on various time scales. This paper presents a time-dependent analysis applied to a selection of flaring gamma-ray blazars observed by the FERMI/LAT experiment and by TeV Cherenkov telescopes using five years of ANTARES data taken from 2008 to 2012. The results are compatible with fluctuations of the background. Upper limits on the neutrino fluence have been produced and compared to the measured gamma-ray spectral energy distribution.Comment: 27 pages, 16 figure

    Uridine Metabolism in HIV-1-Infected Patients: Effect of Infection, of Antiretroviral Therapy and of HIV-1/ART-Associated Lipodystrophy Syndrome

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    Background Uridine has been advocated for the treatment of HIV-1/HAART-associated lipodystrophy (HALS), although its metabolism in HIV-1-infected patients is poorly understood. Methods Plasma uridine concentrations were measured in 35 controls and 221 HIV-1-infected patients and fat uridine in 15 controls and 19 patients. The diagnosis of HALS was performed following the criteria of the Lipodystrophy Severity Grading Scale. Uridine was measured by a binary gradient-elution HPLC method. Analysis of genes encoding uridine metabolizing enzymes in fat was performed with TaqMan RT-PCR. Results Median plasma uridine concentrations for HIV-1-infected patients were 3.80 ”mol/l (interquartile range: 1.60), and for controls 4.60 ”mol/l (IQR: 1.8) (P = 0.0009). In fat, they were of 6.0 (3.67), and 2.8 (4.65) nmol/mg of protein, respectively (P = 0.0118). Patients with a mixed HALS form had a median plasma uridine level of 4.0 (IC95%: 3.40-4.80) whereas in those with isolated lipoatrophy it was 3.25 (2.55-4.15) ”mol/l/l (P = 0.0066). The expression of uridine cytidine kinase and uridine phosphorylase genes was significantly decreased in all groups of patients with respect to controls. A higher expression of the mRNAs for concentrative nucleoside transporters was found in HIV-1-infected patients with respect to healthy controls. Conclusions HIV-1 infection is associated with a decrease in plasma uridine and a shift of uridine to the adipose tissue compartment. Antiretroviral therapy was not associated with plasma uridine concentrations, but pure lipoatrophic HALS was associated with significantly lower plasma uridine concentrations
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