6 research outputs found
A survey for variable young stars with small telescopes: VIII — Properties of 1687 Gaia selected members in 21 nearby clusters
The Hunting Outbursting Young Stars (HOYS) project performs long-term, optical, multi- filter, high cadence monitoring of 25 nearby young clusters and star forming regions. Utilising Gaia DR3 data we have identified about 17000 potential young stellar members in 45 coherent astrometric groups in these fields. Twenty one of them are clear young groups or clusters of stars within one kiloparsec and they contain 9143 Gaia selected potential members. The cluster distances, proper motions and membership numbers are determined. We analyse long term ( 7 yr) V, R, and I-band light curves from HOYS for 1687 of the potential cluster members. One quarter of the stars are variable in all three optical filters, and two thirds of these have light curves that are symmetric around the mean. Light curves affected by obscuration from circumstellar materials are more common than those affected by accretion bursts, by a factor of 2 – 4. The variability fraction in the clusters ranges from 10 to almost 100 percent, and correlates positively with the fraction of stars with detectable inner disks, indicating that a lot of variability is driven by the disk. About one in six variables shows detectable periodicity, mostly caused by magnetic spots. Two thirds of the periodic variables with disk excess emission are slow rotators, and amongst the stars without disk excess two thirds are fast rotators – in agreement with rotation being slowed down by the presence of a disk
A survey for variable young stars with small telescopes – VIII. Properties of 1687 Gaia selected members in 21 nearby clusters
The Hunting Outbursting Young Stars (HOYS) project performs long-term, optical, multi-filter, high cadence monitoring of 25 nearby young clusters and star forming regions. Utilising Gaia DR3 data we have identified about 17000 potential young stellar members in 45 coherent astrometric groups in these fields. Twenty one of them are clear young groups or clusters of stars within one kiloparsec and they contain 9143 Gaia selected potential members. The cluster distances, proper motions and membership numbers are determined. We analyse long term (≈ 7 yr) V, R, and I-band light curves from HOYS for 1687 of the potential cluster members. One quarter of the stars are variable in all three optical filters, and two thirds of these have light curves that are symmetric around the mean. Light curves affected by obscuration from circumstellar materials are more common than those affected by accretion bursts, by a factor of 2 – 4. The variability fraction in the clusters ranges from 10 to almost 100 percent, and correlates positively with the fraction of stars with detectable inner disks, indicating that a lot of variability is driven by the disk. About one in six variables shows detectable periodicity, mostly caused by magnetic spots. Two thirds of the periodic variables with disk excess emission are slow rotators, and amongst the stars without disk excess two thirds are fast rotators – in agreement with rotation being slowed down by the presence of a disk
The Cutaneous Spectrum of Lupus Erythematosus.
Systemic lupus erythematosus is a complex autoimmune disease with a wide spectrum of clinical and immunopathological features. Cutaneous and articular manifestations are the most common signs in patients with systemic lupus erythematosus. We here review the pathogenesis and the new classification of cutaneous lupus erythemathosus with a discussion of the significance of the various cutaneous signs. The lesions are classified according to the level of the cellular infiltrate and tissue damage in the epidermis, dermis, and/or subcutis. Furthermore, cutaneous lesions pointing to the presence of a thrombotic vasculopathy and those due to a distinct inflammatory, neutrophilic-mediated reaction pattern are highlighted. Particular attention will be given in describing the histology of skin manifestation. Treatment options for cutaneous lupus erythemathosus have increased with the introduction of new biological therapies. However, the majority of the patients still benefit from antimalarials, which remain the cornerstone of treatment. The evaluation and management of cutaneous lupus erythemathosus patients depend on the clinical findings and associated symptoms
Vasculite cutânea de pequenos vasos: etiologia, patogênese, classificação e critérios diagnósticos - Parte I Small vessel cutaneous vasculitis: etiology, pathogenesis, classification and diagnostic criteria - Part I
Vasculite é a inflamação da parede dos vasos. Pode variar em gravidade desde doença autolimitada de um único órgão até doença grave com risco de morte por falência de múltiplos órgãos. Existem várias causas, embora só se apresente por poucos padrões histológicos de inflamação vascular. Vasos de qualquer tipo e em qualquer órgão podem ser afetados, resultando em ampla variedade de sinais e sintomas. Diferentes vasculites com apresentações clínicas indistinguíveis têm evolução e tratamento muito diferentes. Essa condição representa desafio para o médico, incluindo classificação, diagnóstico, exames laboratoriais pertinentes, tratamento e seguimento adequado. Neste artigo são revistos a classificação, a etiologia, a patogênese e os critérios diagnósticos das vasculites cutâneas.<br>Vasculitis is an inflammation of vessel walls. It may range in severity from a self-limited disorder in one single organ to a life-threatening disease due to multiple-organ failure. It has many causes, although they result in only a few histological patterns of vascular inflammation. Vessels of any type in any organ can be affected, a fact that results in a broad variety of signs and symptoms. Different vasculitides with indistinguishable clinical presentations have very different prognosis and treatments. This condition presents many challenges to physicians in terms of classification, diagnosis, appropriate laboratory workup, treatment, and the need for careful follow-up. This article reviews the classification, etiology, pathology and diagnostic criteria of cutaneous vasculitis