Aegyptische Chronologie

Book written in German on Egyptian Chronology.https://knowledge.e.southern.edu/kweeks_coll/1031/thumbnail.jp

Episodic excursions of low-mass protostars on the Hertzsprung-Russell diagram

Following our recent work devoted to the effect of accretion on the pre-main-sequence evolution of low-mass stars, we perform a detailed analysis of episodic excursions of low-mass protostars in the Hertzsprung-Russell (H-R) diagram triggered by strong mass accretion bursts typical of FU Orionis-type objects (FUors). These excursions reveal themselves as sharp increases in the stellar total luminosity and/or effective temperature of the protostar and can last from hundreds to a few thousands of years, depending on the burst strength and characteristics of the protostar. During the excursions, low-mass protostars occupy the same part of the H-R diagram as young intermediate-mass protostars in the quiescent phase of accretion. Moreover, the time spent by low-mass protostars in these regions is on average a factor of several longer than that spent by the intermediate-mass stars in quiescence. During the excursions, low-mass protostars pass close to the position of most known FUors in the H-R diagram, but owing to intrinsic ambiguity the model stellar evolutionary tracks are unreliable in determining the FUor properties. We find that the photospheric luminosity in the outburst state may dominate the accretion luminosity already after a few years after the onset of the outburst, meaning that the mass accretion rates of known FUors inferred from the bolometric luminosity may be systematically overestimated, especially in the fading phase.Comment: 15 pages, 12 figure

Disquisitiones de intoxicatione acuta phosphoro effecta : dissertatio inauguralis

http://tartu.ester.ee/record=b2288816~S1*es

Quaedam de morbo leproso inter rusticos Esthonos endemico : dissertatio inauguralis medica

http://tartu.ester.ee/record=b1883749~S1*es

Episodic accretion and mergers during growth of massive protostars

3D simulations of high mass young stellar object (HMYSO) growth show that their circumstellar discs fragment onto multiple self-gravitating objects. Accretion of these by HMYSO may explain episodic accretion bursts discovered recently. We post-process results of a previous 3D simulation of a HMYSO disc with a 1D code that resolves the disc and object dynamics down to the stellar surface. We find that burst-like deposition of material into the inner disc seen in 3D simulations by itself does not always signify powerful accretion bursts. Only high density post-collapse clumps crossing the inner computational boundary may result in observable bursts. The rich physics of the inner disc has a significant impact on the expected accretion bursts: (1) In the standard turbulent viscosity discs, migrating objects can stall at a migration trap at the distance of a few au from the star. However, in discs powered by magnetised winds, the objects are able to cross the trap and produce bursts akin to those observed so far. (2) Migrating objects may interact with and modify the thermal (hydrogen ionisation) instability of the inner disc, which can be responsible for longer duration and lower luminosity bursts in HMYSOs. (3) If the central star is bloated to a fraction of an au by a previous episode of high accretion rate, or if the migrating object is particularly dense, a merger rather than a disc-mediated accretion burst results; (4) Object disruption bursts may be super-Eddington, leading to episodic feedback on HMYSO surroundings via powerful outflows.Comment: 19 pages, 16 figures, accepted to MNRA

Amours et figures décoratives appliqués a l'art industriel

Copia digital. España : Ministerio de Cultura y Deporte. Subdirección General de Coordinación Bibliotecaria, 2018Fecha de 1876 tomada del catálogo de la Biblioteca Naciona

Strong tuberculin response after BCG vaccination is associated with low multiple sclerosis risk: a population-based cohort study

Background: Multiple sclerosis (MS) is characterized by inflammatory lesions in the central nervous system involving pro-inflammatory T-cells. Immune dysregulation is well described in prevalent disease, but it is not known whether this precedes disease development. Bacillus Calmette–Guerin (BCG) vaccination ameliorates MS-like disease in mice. In people vaccinated with BCG, the tuberculin skin test (TST) offers a standardized measure of a T-cell-mediated immune response. We therefore hypothesized that the strength of the TST response after BCG vaccination is associated with subsequent MS risk. Methods: Using data from a Norwegian tuberculosis screening programme (1963–1975), we designed a population-based cohort study and related the size of TST reactions in individuals previously vaccinated with BCG to later MS disease identified through the Norwegian MS registry. We fitted Cox proportional hazard models and flexible parametric survival models to investigate the association between TST reactivity, MS risk and its temporal relationship. Results: Among 279 891 participants (52% females), 679 (69% females) later developed MS. Larger TST reactivity was associated with decreased MS risk. The hazard ratio for MS per every 4-mm increase in skin induration size was 0.86 (95% confidence interval 0.76–0.96) and similar between sexes. The strength of the association persisted for >30 years after the TST. Conclusion: A strong in vivo vaccine response to BCG is associated with reduced MS risk >30 years later. The immunological mechanisms determining TST reactivity suggest that skewed T-cell-mediated immunity precedes MS onset by many decades.publishedVersio

Postvaccination immune responses and risk of primary total hip arthroplasty—A population-based cohort study

Objective To investigate the relationship between individual postvaccination immune responses and subsequent risk of total hip arthroplasty (THA) due to idiopathic osteoarthritis (OA) or rheumatoid arthritis (RA). Method Results of tuberculin skin tests (TSTs) following the Bacille Calmette–Guerin (BCG) vaccination were used as a marker of individual immune responses. TST results from the mandatory mass tuberculosis screening program 1948–1975 (n = 236 770) were linked with information on subsequent THA during 1987–2020 from the Norwegian Arthroplasty Register. The multivariable Cox proportional hazard regression was performed. Results A total of 10 698 individuals received a THA during follow-up. In men, there was no association between TST and risk of THA due to OA (Hazard ratio [HR] 1.01, 95% confidence interval [CI] 0.92–1.12 for positive versus negative TST and HR 1.06, 95% CI 0.95–1.18 for strong positive vs negative TST), while the risk estimates increased with increasingly restrictive sensitivity analyses. In women, there was no association with THA due to OA for positive versus negative TST (HR 0.98, 95% CI 0.92–1.05), while a strong positive TST was associated with reduced risk of THA (HR 0.90, 95% CI 0.84–0.97). No significant associations were observed in the sensitivity analysis for women or for THA due to RA. Conclusion Our results suggest that an increased postvaccination immune response is associated with a nonsignificant trend of increased risk of THA among men and a decreased risk among women, although risk estimates were small.publishedVersio

2,4-Dithiouracil: the reproducible H-bonded structural motifs in the complexes with 18-membered crown ethers

[[abstract]]2,4-Dithiouracil (DTU) forms in the crystals the H-bonded monohydrates of a 1 : 1 : 1 ratio with 18-crown-6 (18C6) 1, cis,syn,cis-isomer of dicyclohexano-18-crown-6 (DCH6A) 2, and benzo-18-crown-6 (B18C6) 3, while the anhydrous adduct with cis,anti,cis-isomer of dicyclohexano-18-crown-6 (DCH6B) 4 is of a 2 : 1 ratio. In 1–3 the components reproducibly alternate in the chains, while in 4 the chains are built of the alternative centrosymmetric dimers of 2,4-dithiouracil and the molecules of the cis,anti,cis-isomer of dicyclohexano-18-crown-6.[[journaltype]]國外[[incitationindex]]SCI[[booktype]]紙本[[booktype]]電子版[[countrycodes]]GB

Percepção dos riscos ocupacionais por profissionais de um laboratório de imunodiagnóstico

Introdução: os profissionais que trabalham nas áreas das ciências biológicas e saúde, no exercício de suas atividades ocupacionais, e os usuários dos serviços de atenção à saúde estão expostos a diversos riscos que, quando não perceptíveis e controlados, podem causar acidentes. Objetivo: descrever a percepção do risco ocupacional e as condições no ambiente de trabalho dos profissionais de um laboratório de imunodiagnóstico em uma instituição brasileira pública de ensino superior. Metodologia: estudo descritivo quantitativo que contou com participação voluntária de profissionais (N=19, 86% do total dos vinculados ao serviço). Os dados foram obtidos através de um questionário estruturado para registro da percepção dos grupos de riscos ambientais físico, químico, biológico, ergonômico e de acidentes no âmbito ocupacional, com base na Portaria 25 de 1994 e Norma Regulamentadora 15 do Ministério do Trabalho e Emprego, assim como, a disponibilidade de equipamentos de proteção individual e coletiva. Resultados: nos registros dos grupos de risco inerentes ao processo de trabalho, o biológico foi o mais presente, devido ao manuseio de amostras sanguíneas e suas frações. Quanto as condições de trabalho, os profissionais informaram que há disponibilidade de equipamentos de proteção adequados e que os mesmos são utilizados nos respectivos setores para contenção e minimização dos riscos. Conclusão: os profissionais demonstraram percepção dos riscos aos quais estão expostos. O laboratório adota a legislação vigente e as exigências de segurança e qualidade. Ações que promovem a minimização da exposição aos riscos ocupacionais devem ser continuadas para manutenção e promoção da saúde destes trabalhadores