Variability in high-mass X-ray binaries

Strongly magnetized, accreting neutron stars show periodic and aperiodic variability over a wide range of time scales. By obtaining spectral and timing information on these different time scales, we can have a closer look into the physics of accretion close to the neutron star and the properties of the accreted material. One of the most prominent time scales is the strong pulsation, i.e., the rotation period of the neutron star itself. Over one rotation, our view of the accretion column and the X-ray producing region changes significantly. This allows us to sample different physical conditions within the column but at the same time requires that we have viewing-angle-resolved models to properly describe them. In wind-fed high-mass X-ray binaries, the main source of aperiodic variability is the clumpy stellar wind, which leads to changes in the accretion rate (i.e., luminosity) as well as absorption column. This variability allows us to study the behavior of the accretion column as a function of luminosity, as well as to investigate the structure and physical properties of the wind, which we can compare to winds in isolated stars.Comment: 6 pages, 4 figures, accepted for publication in Astronomische Nachrichten (proceedings of the XMM-Newton Workshop 2019

Avaliação do comportamento de estacas de Thitonia diversifolia (Hemsley) Gray em sistema agroflorestal na Encosta da Serra do Sudeste, RS.

O objetivo deste trabalho foi avaliar a sobrevivência e produção de biomassa de estacas com diferentes diâmetros de Thitonia diversifolia em condições de campo, fornecendo dados capazes de orientarem a utilização desta planta em sistemas Agroflorestais na região da Encosta da Serra do Sudeste, Rio Grande do Sul

Espécies com potencial para cercas-vicas em SAF's da Região Sul do RS: estudo preliminar.

O presente trabalho tem como objetivo elencar espécies com potencial para cercas-vivas em Sistemas Agroflorestais da região Sul do RS, buscando contribuir para proteção de agroecossistemas. Com base em revisão bibliográfica realizada foram elencadas 81 espécies, das quais 10 foram selecionadas para maior aprofundamento e serão apresentadas neste estudo. Posteriormente estas espécies serão testadas e analisadas em campo. Abstract: The present study aims to list species with potential for living fences in agroforestry systems in southern RS, seeking to contribute to protection of agroecosystems. Based on the literature review were listed 81 species, of which 10 were selected for further deepening and will be presented in this study. Later these species will be tested and evaluated in the ground

Avaliação da superação de dormência de sementes de Cupania vernalis Cambess.

Cupania vernalis pertence à família Sapindaceae e é conhecida popularmente como camboatá. Suas sementes apresentam alto teor de umidade e são classificadas como recalcitrantes. Frente à dificuldade de armazenagem e na busca por métodos que acelerem a germinação e emergência, submeteu-se as sementes a diferentes tratamentos de superação de dormência. Foram testados os processos de escarificação, aquecimento em água quente a 50ºC por 5 minutos, desidratação a 40% e testemunha sem tratamento. As sementes tiveram o arilo removido antes da aplicação dos tratamentos. Para cada um dos tratamentos avaliou-se a emergência durante 30, 60 e 90 dias. O aquecimento em água quente a 50ºC por 5 minutos acelerou o processo de germinação, enquanto que o tratamento desidratação apresentou a menor emergência absoluta, ainda que não tenha provocado a total inviabilidade das sementes. Abstract: Cupania vernalis belongs to the family Sapindaceae and it is known than camboatá. Their seeds have high moisture content and are classified as recalcitrant. Facing the difficulty of storing and for methods to speed up germination and emergence, underwent the seeds to different treatments. Scarification, heating in hot water at 50ºc for 5 minutes, dehydration to 40% and control without treatment where tested. The seeds had the aril removed before application the treatments. For each one of the treatments was evaluated at 30, 60 and emergencies during 90 days. Heating in hot water at 50ºc for 5 minutes accelerated the process of germination, while treating dehydration presented the lowest absolute emergency, even though it has not caused the total impracticality of the seeds

Licenciamento de espécies florestais nativas em sistemas agroflorestais no contexto da agricultura familiar.

O estudo está sendo realizado em três agroecossistemas que participam do projeto de pesquisa ?Construção participativa de sistemas agroflorestais no território sul do Rio Grande do Sul ? Encosta da Serra do Sudeste?, onde foram implantadas unidades pedagógicas de sistemas agroflorestais (SAFs). O presente trabalho consiste em exercitar o processo de licenciamento de plantios florestais com espécies nativas. Para tanto, tem-se realizado revisão bibliográfica e de fontes secundárias, entrevistas com os agentes licenciadores e famílias agricultoras, com o intuito de esclarecer, problematizar e qualificar os procedimentos administrativos e legais para que um agricultor possa plantar, manejar e colher produtos madeireiros e não-madeireiros, oriundos de espécies florestais nativas, atendendo as exigências da legislação ambiental. Abstract The study was conducted in three agroecosystems that participate in the research project "construction development of agroforestry systems in the territory south of the Rio Grande do Sul - South East Side of the Sierra," where units were deployed teaching agroforestry systems (AFS). The present work consists in exercising the licensing process forest plantations with native species. For both, we have performed bibliographic review and secondary sources, interviews with the licensors and farming families, with the intention of clarify, problematize and qualify the administrative and legal procedures necessary for that a farmer to plant, manage and harvest timber and non-wood from native forest species, meeting the requirement of environmental legislation

Vela X-1 as a laboratory for accretion in High-Mass X-ray Binaries

Vela X-1 is an eclipsing high mass X-ray binary (HMXB) consisting of a 283s accreting X-ray pulsar in a close orbit of 8.964 days around the B0.5Ib supergiant HD77581 at a distance of just 2.4 kpc. The system is considered a prototype of wind-accreting HMXB and it has been used as a baseline in different theoretical or modelling studies. We discuss the observational properties of the system and the use of the observational data as laboratory to test recent developments in modelling the accretion process in High-Mass X-ray Binaries (e.g., Sander et al. 2018; El Mellah et al. 2018), which range from detailed descriptions of the wind acceleration to modelling of the structure of the flow of matter close to the neutron star and its variations.Comment: 4 pages, 2 figures, proceedings of the 12th INTEGRAL conference "INTEGRAL looks AHEAD to Multimessenger astronomy" in Geneva (Switzerland) on 11-15 February 201

Mutations in the EXT1 and EXT2 genes in Spanish patients with multiple osteochondromas

Multiple osteochondromas is an autosomal dominant skeletal disorder characterized by the formation of multiple cartilage-capped tumours. Two causal genes have been identified, EXT1 and EXT2, which account for 65% and 30% of cases, respectively. We have undertaken a mutation analysis of the EXT1 and EXT2 genes in 39 unrelated Spanish patients, most of them with moderate phenotype, and looked for genotype-phenotype correlations. We found the mutant allele in 37 patients, 29 in EXT1 and 8 in EXT2. Five of the EXT1 mutations were deletions identified by MLPA. Two cases of mosaicism were documented. We detected a lower number of exostoses in patients with missense mutation versus other kinds of mutations. In conclusion, we found a mutation in EXT1 or in EXT2 in 95% of the Spanish patients. Eighteen of the mutations were novel.Fil: Sarrión, P.. Universidad de Barcelona; EspañaFil: Sangorrin, A.. Hospital Sant Joan de Déu; EspañaFil: Urreizti, R.. Universidad de Barcelona; EspañaFil: Delgado, María Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Córdoba; ArgentinaFil: Artuch, R.. Hospital Sant Joan de Déu; EspañaFil: Martorell, L.. Hospital Sant Joan de Déu; EspañaFil: Armstrong, J.. Hospital Sant Joan de Déu; EspañaFil: Anton, J.. Hospital Sant Joan de Déu; EspañaFil: Torner, F.. Hospital Sant Joan de Déu; EspañaFil: Vilaseca, M. A.. Hospital Sant Joan de Déu; EspañaFil: Nevado, J.. Hospital Universitario La Paz; EspañaFil: Lapunzina, P.. Hospital Universitario La Paz; EspañaFil: Asteggiano, Carla Gabriela. Universidad Nacional de Córdoba; Argentina. Universidad Católica de Córdoba; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Balcells, S.. Universidad de Barcelona; EspañaFil: Grinberg, D.. Universidad de Barcelona; Españ

The prototype X-ray binary GX 339-4:using TeV γ-rays to assess LMXBs as Galactic cosmic ray accelerators

Since the discovery of cosmic rays (CRs) over a century ago, their origin remains an open question. Galactic CRs with energy up to the knee ($10^{15}$ eV) are considered to originate from supernova remnants, but this scenario has recently been questioned due to lack of TeV $\gamma$-ray counterparts in many cases. Extragalactic CRs on the other hand, are thought to be associated with accelerated particles in the relativistic jets launched by supermassive accreting black holes at the center of galaxies. Scaled down versions of such jets have been detected in X-ray binaries hosting a stellar black hole (BHXBs). In this work, we investigate the possibility that the smaller-scale jets in transient outbursts of low-mass BHXBs could be sources of Galactic CRs. To better test this scenario, we model the entire electromagnetic spectrum of such sources focusing on the potential TeV regime, using the `canonical' low-mass BHXB GX 339-4 as a benchmark. Taking into account both the leptonic radiative processes and the $\gamma$-rays produced via neutral pion decay from inelastic hadronic interactions, we predict the GeV and TeV $\gamma$-ray spectrum of GX 339-4 using lower-frequency emission as constraints. Based on this test-case of GX 339-4 we investigate whether other, nearby low-mass BHXBs could be detected by the next-generation very-high-energy $\gamma$-ray facility the Cherenkov Telescope Array, which would establish them as additional and numerous potential sources of CRs in the Galaxy.Comment: 13 pages, 12 figures, accepted to MNRA