Detailed opacity calculations for astrophysical applications

Nowadays, several opacity codes are able to provide data for stellar structure models, but the computed opacities may show significant differences. In this work, we present state-of-the-art precise spectral opacity calculations, illustrated by stellar applications. The essential role of laboratory experiments to check the quality of the computed data is underlined. We review some X-ray and XUV laser and Z-pinch photo-absorption measurements as well as X-ray emission spectroscopy experiments involving hot dense plasmas produced by ultra-high-intensity laser irradiation. The measured spectra are systematically compared with the fine-structure opacity code SCO-RCG. Focus is put on iron, due to its crucial role in understanding asteroseismic observations of $\beta$ Cephei-type and Slowly Pulsating B stars, as well as of the Sun. For instance, in $\beta$ Cephei-type stars, the iron-group opacity peak excites acoustic modes through the "kappa-mechanism". A particular attention is paid to the higher-than-predicted iron opacity measured at the Sandia Z-machine at solar interior conditions. We discuss some theoretical aspects such as density effects, photo-ionization, autoionization or the "filling-the-gap" effect of highly excited states.Comment: submitted to "Atoms

The Triassic-Jurassic boundary in eastern North America

Rift basins of the Atlantic passive margin in eastern North America are filled with thousands of meters of continental rocks termed the Newark Supergroup which provide an unprecedented opportunity to examine the fine scale structure of the Triassic-Jurassic mass extinction in continental environments. Time control, vital to the understanding of the mechanisms behind mass extinctions, is provided by lake-level cycles apparently controlled by orbitally induced climate change allowing resolution at the less than 21,000 year level. Correlation with other provinces is provided by a developing high resolution magnetostratigraphy and palynologically-based biostratigraphy. A large number of at least local vertebrate and palynomorph extinctions are concentrated around the boundary with survivors constituting the earliest Jurassic assemblages, apparently without the introduction of new taxa. The palynofloral transition is marked by the dramatic elimination of a relatively high diversity Triassic pollen assemblage with the survivors making up a Jurassic assemblage of very low diversity overwhelmingly dominated by Corollina. Based principally on palynological correlations, the hypothesis that these continental taxonomic transitions were synchronous with the massive Triassic-Jurassic marine extinctions is strongly corroborated. An extremely rapid, perhaps catastrophic, taxonomic turnover at the Triassic-Jurassic boundary, synchronous in continental and marine realms is hypothesized and discussed

Detailed Opacity Calculations for Stellar Models

Radiative opacity is an important quantity in the modeling of stellar structure and evolution. In the present work we recall the role of opacity in the interpretation of pulsations of different kinds of stars. The detailed opacity code SCO-RCG for local-thermodynamic-equilibrium (LTE) plasmas is described, as well as the OPAMCDF project dedicated to the spectroscopy of LTE and non-LTE plasmas. Interpretations, with the latter codes, of several laser and Z pinch experiments in conditions relevant to astrophysical applications are also presented and our work in progress as concerns the internal solar conditions is illustrated.Comment: submitted to ASP Conf. Se

The Comet : Creative Life in Our Town, June 1983

Free newspaper in Portland, Maine devoted to local arts and culture. The June 1983 issue includes a feature article about The People\u27s Building (155 Brackett Street) which housed The Good Day Market Cooperative, Portland West Neighborhood Planning Council, Youth in Action, and various community resources. Additional articles include a biography of local dancer Brian Crabtree, photos taken by Fox School of Photography students, and short stories by local writers

The Comet : Creative Life in Our Town, April 1983

Free newspaper in Portland, Maine devoted to local arts and culture. The April 1983 issue includes articles about life near Middle Street in the 1930s; Bill Dowd, owner of The Loft, Moose Alley blues club, Bottoms Up, and Popeye\u27s Ice House; Portland\u27s waterfront

The impact of host language proficiency on employability and workplace language use

Treballs Finals del Màster d'Economia, Facultat d'Economia i Empresa, Universitat de Barcelona. Curs: 2023-2024, Tutor: Antonio Di PaoloThe paper investigates the impact of Spanish language proficiency among immigrants on employability and the use of Spanish in the workplace in Spain, using data from the "Encuesta de Características Esenciales de la Población y las Viviendas" which complements the 2021 census. Employing an Instrumental Variable (IV) strategy based on the critical period hypothesis of language acquisition, we refine the methodological approach by considering the mother tongue effects of immigrants and enhancing the exogenous assignment of Spanish proficiency through the instrument. Contrary to previous findings in Spain, the IV results suggest that Spanish proficiency does not significantly affect employment probability. However, proficient individuals show a substantial increase in the use of Spanish in the workplace, with slightly heterogeneous effects by sex. Correcting for endogeneity and classification error, Spanish-proficient immigrants present a significantly higher workplace host language use. The findings suggest a considerable downward bias in the OLS estimates, indicating that the effect of Spanish proficiency results in much greater integration benefits in the workplace, measured by host language use on the job. The study underscores the role of language in facilitating labor market integration by examining a new labor market integration outcome in a recent context. Our findings provide nuanced insights into immigrant labor market dynamics, offering valuable implications for policymakers aiming to foster inclusive workplaces

Path, Plaza, and Park: Cross-Programming Space in the City

“I tend to operate by variations…When (I) think about the construction of a wall...I am interested in thinking about all of the possibilities that this element can or could contain…I never work by reduction: I try to reveal the multiplicities, the singularities…” --Enric Miralles Enric Miralles’ adaptable architecture and furniture designs are not merely the combination of disparate things. His designs combine programs and elements which are complimentary and serve to strengthen each other. They can change according to time of day, needs for privacy, requirements for work or play, the number of people using them, storage needs, etc. The above quote by Miralles illustrates how he combines multiple programs, or stories, to create just one object. Like Miralles, I am interested in all of the potentials that a single piece of architecture contains. With careful planning in regards to the needs of the users, the possibilities of the site, and the requirements of the larger city or neighborhood, such programs can be realized in a single multi-faceted project. Such a project can contribute to the life of a city (the physical composition of its structures, the interaction of its people, and the vibrancy of its public spaces) through an architecture of flexibility and experiential connections that serves the different needs and program requirements of individual users and the conditions of the site and city

Evolution of employment of female immigrants in the Spanish labour market. The impact of the current financial crisis

Este artículo aborda el impacto de la actual crisis económica sobre el nivel de ocupación de las mujeres inmigrantes. Para ello se utilizan datos de la Encuesta de Población Activa desde 2000 hasta 2010. Los resultados muestran que las mujeres extranjeras están soportando mejor el efecto de la recesión que sus connacionales, cuyas tasas de paro han crecido en mayor medida. Además, el capital humano de las mujeres inmigrantes ofrece una mayor resistencia frente a la caída de la tasa de empleo que el de los inmigrantes varones. A partir de la recesión, el nivel de ocupación de las mujeres españolas es de todos los grupos el que experimenta pérdidas más moderadas, aunque en su caso un nivel educativo alto no implica un descenso más suave de la tasa de empleo. Por otra parte, un mayor tiempo en el mercado laboral sólo parece ser un factor de protección en el caso de las mujeres españolas.This paper explores the impact of the current financial crisis on employment of female immigrants by conducting empirical analysis based on the Spanish Labour Force Survey, from 2000 until 2010. Results show that female immigrants are less affected by the recession in comparison to male immigrants. At the same time, human capital of female immigrants is more effective against the employment fall in comparison to male immigrants, of which the unemployment rate shows a higher growth. As for Spanish women, employment rates show the smallest drop since the recession, having the same effect on high as well as low educated women. Finally, time in the labour market only has a positive impact on prospects of female natives