Fundamental parameters related to selenium kα and kβ emission x-ray spectra

This research was funded in part by FCT (Portugal) under research center grants UID/FIS/04559/2020 (LIBPhys) and UID/MULTI/04046/2020 (BioISI). This work was also funded through the project PTDC/FIS-AQM/31969/2017, "Ultra-high-accuracy x-ray spectroscopy of transition metal oxides and rare earths." J.M. and J.P.S acknowledge the support of EMPIR, under Contract No. 17FUN02MetroMMC. The EMPIR initiative is co-funded by the European Union's Horizon 2020 research and innovation programme and the EMPIR participating States.We present relativistic ab initio calculations of fundamental parameters for atomic selenium, based on the Multiconfiguration Dirac-Fock method. In detail, fluorescence yields and subshell linewidths, both of K shell, as well as Kβ to Kα intensity ratio are provided, showing overall agreement with previous theoretical calculations and experimental values. Relative intensities were evaluated assuming the same ionization cross-section for the K-shell hole states, leading to a statistical distribution of these initial states. A method for estimating theoretical linewidths of X-ray lines, where the lines are composed by a multiplet of fine-structure levels that are spread in energy, is proposed. This method provides results that are closer to Kα1,2 experimental width values than the usual method, although slightly higher discrepancies occur for the Kβ1,3 lines. This indicates some inaccuracies in the calculation of Auger rates that have a higher contribution for partial linewidths of the subshells involved in the Kβ1,3 profile. Apart from this, the calculated value of Kβ to Kα intensity ratio, which is less sensitive to Auger rates issues, is in excellent agreement with recommended values.publishersversionpublishe

Una mirada crítica desde la izquierda : homenaje a Luz Felipe Falcão

Este libro es un homenaje al historiador brasileño Luiz Felipe Falcão, que presenta tanto investigaciones que fueron influenciadas por sus aportes como rememora su tarea como maestro. Así Igor Goicovic, Gerardo Necoechea, Mariana Mastrángelo, Reinaldo Lohn, Emerson Campos, Paula Godinho, Ronaldo Munck, Silvia Fávero, entre otros, recuerdan la contribución de Felipe, que trascendió sus fronteras nacionales. Fue un ejemplo del historiador como militante, heredero de las mejores tradiciones de aquella generación que entre 1960 y 1980 trató de tomar el cielo por asalto

Escala de atitudes frente ao HIV/AIDS: análise de fatores HIV/AIDS attitudes scale: factorial analysis

OBJETIVO: Este trabalho apresenta resultados acerca das propriedades psicométricas da "Escala de atitudes frente ao HIV/AIDS". Os dados, provenientes de uma amostra de 549 alunos entre universitários, ensinos médio e ensino fundamental. MÉTODOS: Os dados foram tratados pelo método dos componentes principais da análise fatorial. A análise final, postulado um eigenvalue mínimo de 2, resultou cinco fatores. Foram eliminados itens que apresentaram carga fatorial menor que 0,30. Neste estudo, o menor alfa observado foi de 0,79. Portanto, é provável que todos os 47 itens do instrumento final elaborado meçam o mesmo construto: atitude frente ao HIV/AIDS. RESULTADOS: Escores inferiores a 96 foram considerados "fraco grau de conhecimento sobre HIV/AIDS"; entre 96 e 192 "moderado grau de conhecimento" e acima de 192 "alto grau de conhecimento sobre HIV/AIDS". Foram estabelecidos os fatores: 1, 2 e 3, sendo "fator geral de percepção da informação técnico-científica"; "fator de percepção da informação técnico-científica versus sexualidade e preconceito"; "fator de percepção da informação técnico-científica no uso de drogas", respectivamente. CONCLUSÕES: O alfa de Cronbach encontrado para a escala como um todo foi de 0,859, sugerindo fortemente a existência da fidedignidade do instrumento que se mostrou útil para avaliar o grau de conhecimento acerca do HIV/AIDS e o risco decorrente do desconhecimento, entre estudantes.<br>OBJETIVE: This paper presents results related to the psychometric properties of the Escala de atitudes frente a HIV/AIDS (Attitudes Towards HIV/AIDS Scale). METHODS: The data was derived from a sample with 549 high and elementary school level students. The data was treated by Principal Components Analysis (PCA) and Factor Analysis (FA). The final analysis resulted in 5 factors, given a minimal eigenvalue 2. Factor load items lower than 0.30 were excluded. In this study, the lowest alpha observed was 0.79. Therefore, it is likely that all 47 final tool items measure the same construct: attitude towards HIV/AIDS. RESULTS: Scores < 96 were considered "low knowledge amount on HIV/AIDS"; scores between 96 and 192 meant "moderate knowledge amount on HIV/AIDS", and scores > 192 were considered "high knowledge amount on HIV/AIDS". Factors 1, 2, and 3, i.e. "Technical/Scientific Information Perception General Factor"; "Technical/Scientific Information Perception Factor versus Sexuality and Prejudice"; "Technical/Scientific Information Perception Factor in Drug Abuse", respectively, were created. CONCLUSIONS: Cronbach’s alpha found for the scale as a whole was 0.859 and strongly suggests reliability of the tool, as it showed useful to evaluate the knowledge amount regarding HIV/AIDS and the risk resulting from lack of knowledge among students