212 research outputs found
Photometric and spectroscopic variability of the FUor star V582 Aurigae
We carried out BVRI CCD photometric observations in the field of V582 Aur
from 2009 August to 2013 February. We acquired high-, medium-, and
low-resolution spectroscopy of V582 Aur during this period. To study the
pre-outburst variability of the target and construct its historical light
curve, we searched for archival observations in photographic plate collections.
Both CCD and photographic observations were analyzed using a sequence of 14
stars in the field of V582 Aur calibrated in BVRI. The pre-outburst
photographic observations of V582 Aur show low-amplitude light variations
typical of T Tauri stars. Archival photographic observations indicate that the
increase in brightness began in late 1984 or early 1985 and the star reached
the maximum level of brightness at 1986 January. The spectral type of V582 Aur
can be defined as G0I with strong P Cyg profiles of H alpha and Na I D lines,
which are typical of FU Orionis objects. Our BVRI photometric observations show
large amplitude variations V~2.8 mag. during the 3.5 year period of
observations. Most of the time, however, the star remains in a state close to
the maximum brightness. The deepest drop in brightness was observed in the
spring of 2012, when the brightness of the star fell to a level close to the
pre-outburst. The multicolor photometric data show a color reversal during the
minimum in brightness, which is typical of UX Ori variables. The corresponding
spectral observations show strong variability in the profiles and intensities
of the spectral lines (especially H alpha), which indicate significant changes
in the accretion rate. On the basis of photometric monitoring performed over
the past three years, the spectral properties of the maximal light, and the
shape of the long-term light curve, we confirm the affiliation of V582 Aur to
the group of FU Orionis objects.Comment: 9 pages, 8 figures, accepted for publication in A&
Clinical cases of pulmonary tuberculosis as a result of TNF antagonist therapy
През последните 12 години антагонистите на TNF са били успешно използвани за лечение на много пациенти страдащи от хронични възпалителни заболявания. Това лечение увеличава риска от туберкулоза до 25 пъти. Дължи се на факта, че TNF и TNF-рецепторите играят важна роля в медиирането на имунния отговор при остри и хронични възпаления. Ето защо всички пациенти, на които предстои подобно лечение трябва да бъдат подложени на стриктна оценка за изключване на активна и латентна туберкулозна инфекция. През 2010 г. беше публикуван консенсус на TBNET, озаглавен „Рискът от туберкулоза, свързан с лечение с TNF антагонисти`.В изложението са представени два случая на белодробна туберкулоза, които са наблюдавани в хода на провеждано лечение с TNF антагонисти при болни с доказани възпалителни заболявания на червата.During the past 12 years TNF antagonists have been successfully used for the treatment of many patients suffering from chronic inflammatory diseases. This treatment increases the risk of tuberculosis up to 25 times. This is due to the fact that TNF and TNF-receptors play an important role in mediating the immune response in acute and chronic inflammation. Therefore all patients undergoing such treatment should be subject to rigorous assessment to exclude active and latent tuberculosis infection. In 2010 a TBNET consensus was published entitled "The risk of tuberculosis related to TNF therapies." In this article we present two cases of pulmonary tuberculosis, which were observed in the course of an ongoing treatment with TNF antagonists in patients with proven inflammatory bowel disease
Longidorus israelensis sp. n. (Nematoda : Dorylaimoidea), a parasite of carrot in Israel
#Longidorus israelensis sp. n., espèce parthénogénétique associée à des dégâts sur carotte en Israël, est décrite. Cette espèce est caractérisée par une grande longueur du corps (7,1-9,1 mm), une région labiale légèrement en relief et aplatie frontalement, des poches amphidiennes non bilobées, un long odontostyle (125-135 micromètres) et une queue courte, sub-hémisphérique (36-46 micromètres). Elle présente également une disposition inhabituelle des noyaux des glandes oesophagiennes. Les carottes attaquées par #L. israelensis sp. n. voient la croissance de leurs racines stoppée, le départ de racines secondaires et l'apparition de renflements à l'extrémité des racines. Il en résulte des carottes déformées et divisées en pluseiurs parties. Le nématode est généralement rencontré à des profondeurs du sol variant de 20 à 40 cm mais il peut migrer jusqu'à 40-100 cm de profondeur de façon à survivre pendant la période estivale chaude et sèche. (Résumé d'auteur
Multi-band optical-NIR variability of blazars on diverse timescales
To search for optical variability on a wide range of timescales, we have
carried out photometric monitoring of two flat spectrum radio quasars, 3C 454.3
and 3C 279, plus one BL Lac, S5 0716+714, all of which have been exhibiting
remarkably high activity and pronounced variability at all wavelengths. CCD
magnitudes in B, V, R and I pass-bands were determined for 7000 new
optical observations from 114 nights made during 2011 - 2014, with an average
length of 4 h each, at seven optical telescopes: four in Bulgaria, one
in Greece, and two in India. We measured multiband optical flux and colour
variations on diverse timescales. Discrete correlation functions were computed
among B, V, R, and I observations, to search for any time delays. We found weak
correlations in some cases with no significant time lags. The structure
function method was used to estimate any characteristic time-scales of
variability. We also investigated the spectral energy distribution of the three
blazars using B, V, R, I, J and K pass-band data. We found that the sources
almost always follows a bluer-when-brighter trend. We discuss possible physical
causes of the observed spectral variability.Comment: Accepted for publication in MNRAS, 16 pages, 11 figures, 5 tables,
plus supplementary material containing additional figures and tables (please
contact authors for it
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