Single and Double Photoionization and Photodissociation of Toluene by Soft X-rays in Circumstellar Environment

The formation of polycyclic aromatic hydrocarbons (PAHs) and their methyl derivatives occurs mainly in the dust shells of asymptotic giant branch (AGB) stars. The bands at 3.3 and 3.4 $\mu$m, observed in infrared emission spectra of several objects, are attributed C-H vibrational modes in aromatic and aliphatic structures, respectively. In general, the feature at 3.3 $\mu$m is more intense than the 3.4 $\mu$m. Photoionization and photodissociation processes of toluene, the precursor of methylated PAHs, were studied using synchrotron radiation at soft X-ray energies around the carbon K edge with time-of-flight mass spectrometry. Partial ion yields of a large number of ionic fragments were extracted from single and 2D-spectra, where electron-ion coincidences have revealed the doubly charged parent-molecule and several doubly charged fragments containing seven carbon atoms with considerable abundance. \textit{Ab initio} calculations based on density functional theory were performed to elucidate the chemical structure of these stable dicationic species. The survival of the dications subjected to hard inner shell ionization suggests that they could be observed in the interstellar medium, especially in regions where PAHs are detected. The ionization and destruction of toluene induced by X-rays were examined in the T Dra conditions, a carbon-rich AGB star. In this context, a minimum photodissociation radius and the half-life of toluene subjected to the incidence of the soft X-ray flux emitted from a companion white dwarf star were determined.Comment: 11 pages, 4 figures, accept for publication in Ap

Clinical and Laboratory Features of 184 Italian Pediatric Patients Affected with Selective IgA Deficiency (SIgAD): a Longitudinal Single-Center Study

PURPOSE: Selective IgA deficiency (SIgAD) is the most common humoral primary immunodeficiency. Long-term follow-up data in large cohort of pediatric patients are scarce. METHODS: We report on a single-center cohort of 184 pediatric patients affected with selective IgA deficiency and describe the characteristics at diagnosis and during follow-up. RESULTS: Respiratory infections were the most common clinical finding leading to the initial diagnosis (62%). Positive family history for antibody deficiencies (selective IgA deficiency, common variable immunodeficiency) led to SIgAD diagnosis in 16% of cases. During follow-up, while the incidence of respiratory infections was not particularly high, gastrointestinal symptoms were reported in 27% of patients. Allergic manifestations were found in 23% at diagnosis and an additional 16% of patients during follow-up, leading to a prevalence of atopy of 39% among SIgAD patients. Autoimmune manifestations, excluding celiac disease, were found in 9% of affected patients during follow-up. Celiac disease was found in a high prevalence (14%). Increase of serum IgA levels to partial deficiency (9%) and normal serum levels for age (4%) was observed during follow-up. A small percentage of patients (2%) progressed to common variable immunodeficiency (CVID). CONCLUSIONS: In conclusion, this is the first study to describe a large single-center pediatric cohort of patients affected with SIgAD, revealing that overall most patients do well with regard to infections. Many develop CD, at a rate much higher than the general population. A few normalize their IgA levels. A few progress to CVID. Thus, careful follow-up is suggested to diagnose and treat potential complications earlier for avoiding potential morbidities

Astrochemical evolution along star formation: overview of the IRAM Large Program ASAI

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Profissão docente na instituição escolar: a historicidade das práticas e culturas profissionais Teacher profession in the school institution: the historicity of the practices and professional cultures

Neste ensaio, apresentamos para debate um tema bastante tratado no campo da pesquisa em educação: a constituição da profissão docente. Muito já se produziu a respeito dessa temática considerando, por exemplo, a relação entre o trabalho e a condição de classe, de gênero e a identidade profissional constituída ao longo da trajetória de vida dos docentes. Nosso intuito é mostrar a relevância de pesquisas que procurem compreender a realização da profissão docente nas instituições escolares a partir da investigação das práticas sociais que nela se realizam e, ao mesmo tempo, reafirmar a importância da perspectiva teórico-metodológica marxista para esta análise, especialmente porque nos remetem à historicidade das práticas profissionais. A reorientação das políticas educacionais parece indicar a valorização do docente - ideologia do profissionalismo - e ao mesmo tempo contém os elementos que permitirão no cotidiano da escola, aprofundar os processos de realização de trabalho alienado. Paralelamente ao processo de reforma educacional, observa-se a produção de análises fundamentadas em conceitos "pós-modernos" a orientar a compreensão do trabalho, da formação e da própria constituição da profissão docente. Sem pretender esgotar a vasta bibliografia já produzida sobre o assunto, apontamos alguns limites desses conceitos para a compreensão da profissão docente, os quais parecem coincidir com os pressupostos neoliberais nas políticas educacionais, o que, no nosso entender, reafirma a relevância das categorias marxistas para a pesquisa em educação.<br>In this essay we present a subject-matter frequently faced in the educational research field: the constitution of the teacher's profession. A lot has been written about this subject-matter, considering, for instance, the relation between work and class condition, gender and the professional identity constituted along the trajectory of the teacher's life. Our aim is to stress the relevance of this research that tries to understand teachers in scholarly institutions by investigating the social practices put into practice. By so doing, we emphasize the importance of the Marxist theoretical-methodological approach, since it clarifies the historicalness of professional practices. The reorientation in educational policies seems to indicate a valorization of the teacher - ideology of professionalism - at the same time that it contains the elements that will permit probing in the school's everyday life and the processes of alienated work. Simultaneously with the educational reform process, one can observe the production of analysis grounded in 'post-modern' concepts, orienting the understanding of the teacher's work formation and the constitution of the teacher's job. Without trying to render account of the huge bibliography dealing with those matters, we try to highlight the limits of these post-modern concepts to understanding the teacher's job, which seems to coincide with neo-liberal educational policy presuppositions. This coincidence, to our understanding, only stresses the importance of Marxist categories for the research in education