57 research outputs found

    On the accretion disc properties in eclipsing dwarf nova EM Cyg

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    In this paper we analyzed the behavior of the unusual dwarf nova EM Cyg using the data obtained in April-October, 2007 in Vyhorlat observatory (Slovak Republic) and in September, 2006 in Crimean Astrophysical Observatory (Ukraine). During our observations EM Cyg has shown outbursts in every 15-40 days. Because on the light curves of EM Cyg the partial eclipse of an accretion disc is observed we applied the eclipse mapping technique to reconstruct the temperature distribution in eclipsed parts of the disc. Calculations of the accretion rate in the system were made for the quiescent and the outburst states of activity for different distances.Comment: 6 pages, 3 figures, accepted in Astrophysics and Space Scienc

    Observation of exclusive DVCS in polarized electron beam asymmetry measurements

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    We report the first results of the beam spin asymmetry measured in the reaction e + p -> e + p + gamma at a beam energy of 4.25 GeV. A large asymmetry with a sin(phi) modulation is observed, as predicted for the interference term of Deeply Virtual Compton Scattering and the Bethe-Heitler process. The amplitude of this modulation is alpha = 0.202 +/- 0.028. In leading-order and leading-twist pQCD, the alpha is directly proportional to the imaginary part of the DVCS amplitude.Comment: 6 pages, 5 figure

    AE Aquarii represents a new subclass of Cataclysmic Variables

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    We analyze properties of the unique nova-like star AE Aquarii identified with a close binary system containing a red dwarf and a very fast rotating magnetized white dwarf. It cannot be assigned to any of the three commonly adopted sub-classes of Cataclysmic Variables: Polars, Intermediate Polars, and Accreting non-magnetized White Dwarfs. Our study has shown that the white dwarf in AE Aqr is in the ejector state and its dipole magnetic moment is μ 1.5×1034Gcm3\mu ~ 1.5 \times 10^{34} G cm^3. It switched into this state due to intensive mass exchange between the system components during a previous epoch. A high rate of disk accretion onto the white dwarf surface resulted in temporary screening of its magnetic field and spin-up of the white dwarf to its present spin period. Transition of the white dwarf to the ejector state had occurred at a final stage of the spin-up epoch as its magnetic field emerged from the accreted plasma due to diffusion. In the frame of this scenario AE Aqr represents a missing link in the chain of Polars evolution and the white dwarf resembles a recycled pulsar.Comment: accepted for publication in Astronomy Reports (July 2012

    Post-acute COVID-19 neuropsychiatric symptoms are not associated with ongoing nervous system injury

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    A proportion of patients infected with severe acute respiratory syndrome coronavirus 2 experience a range of neuropsychiatric symptoms months after infection, including cognitive deficits, depression and anxiety. The mechanisms underpinning such symptoms remain elusive. Recent research has demonstrated that nervous system injury can occur during COVID-19. Whether ongoing neural injury in the months after COVID-19 accounts for the ongoing or emergent neuropsychiatric symptoms is unclear. Within a large prospective cohort study of adult survivors who were hospitalized for severe acute respiratory syndrome coronavirus 2 infection, we analysed plasma markers of nervous system injury and astrocytic activation, measured 6 months post-infection: neurofilament light, glial fibrillary acidic protein and total tau protein. We assessed whether these markers were associated with the severity of the acute COVID-19 illness and with post-acute neuropsychiatric symptoms (as measured by the Patient Health Questionnaire for depression, the General Anxiety Disorder assessment for anxiety, the Montreal Cognitive Assessment for objective cognitive deficit and the cognitive items of the Patient Symptom Questionnaire for subjective cognitive deficit) at 6 months and 1 year post-hospital discharge from COVID-19. No robust associations were found between markers of nervous system injury and severity of acute COVID-19 (except for an association of small effect size between duration of admission and neurofilament light) nor with post-acute neuropsychiatric symptoms. These results suggest that ongoing neuropsychiatric symptoms are not due to ongoing neural injury

    Large-scale phenotyping of patients with long COVID post-hospitalization reveals mechanistic subtypes of disease

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    One in ten severe acute respiratory syndrome coronavirus 2 infections result in prolonged symptoms termed long coronavirus disease (COVID), yet disease phenotypes and mechanisms are poorly understood1. Here we profiled 368 plasma proteins in 657 participants ≥3 months following hospitalization. Of these, 426 had at least one long COVID symptom and 233 had fully recovered. Elevated markers of myeloid inflammation and complement activation were associated with long COVID. IL-1R2, MATN2 and COLEC12 were associated with cardiorespiratory symptoms, fatigue and anxiety/depression; MATN2, CSF3 and C1QA were elevated in gastrointestinal symptoms and C1QA was elevated in cognitive impairment. Additional markers of alterations in nerve tissue repair (SPON-1 and NFASC) were elevated in those with cognitive impairment and SCG3, suggestive of brain–gut axis disturbance, was elevated in gastrointestinal symptoms. Severe acute respiratory syndrome coronavirus 2-specific immunoglobulin G (IgG) was persistently elevated in some individuals with long COVID, but virus was not detected in sputum. Analysis of inflammatory markers in nasal fluids showed no association with symptoms. Our study aimed to understand inflammatory processes that underlie long COVID and was not designed for biomarker discovery. Our findings suggest that specific inflammatory pathways related to tissue damage are implicated in subtypes of long COVID, which might be targeted in future therapeutic trials

    FRUITY AROMA PRODUCTION BY Ceratocystis fimbriata IN SOLID CULTURES FROM AGRO-INDUSTRIAL WASTES

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    Solid state fermentations were carried out to test the efficacy of Ceratocystis fimbriata to grow on different agro-industrial substrates and aroma production. Seven media were prepared using cassava bagasse, apple pomace, amaranth and soya bean. All the media supported fungal growth. While amaranth medium produced pineapple aroma, media containing cassava bagasse, apple pomace and soya bean produced a strong fruity aroma. The aroma production was growth dependent and the maximum aroma intensity was detected a few hours before or after the maximum respirometric activity. Sixteen compounds were separated by gas cromatography of the components present in the headspace and fifteen of them were identified as acid (1), alcohols (6), aldehyde (1), ketones (2) and esters (5).<br>Este estudo explorou a versatilidade de Ceratocystis fimbriata de crescer e produzir aromas naturais sobre substratos de resíduos agro-industriais. Bagaço de mandioca, bagaço de maçã, amaranto e soja em diferentes proporções compuseram os sete meios utilizados, mostrando ser substratos adequados para o crescimento e produção de aroma por este fungo em fermentação no estado sólido. Todos os meios contendo bagaço de mandioca, bagaço de maçã e soja em sua composição proporcionaram um forte aroma frutal, enquanto, o meio de amaranto produziu um agradável aroma de abacaxi. A produção de aroma foi dependente do crescimento, visto que a máxima intensidade do aroma foi detectado poucas horas antes ou depois da atividade respiratória máxima. Foram detectados dezesseis compostos pela cromatografia de gás no headspace das culturas, e quinze deles foram identificados: 1 ácido, 6 alcoois, 1 aldeído, 2 cetonas e 5 ésteres
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