High-Resolution Observations of Interstellar Ca I Absorption -- Implications for Depletions and Electron Densities in Diffuse Clouds

We present high-resolution (FWHM ~ 0.3-1.5 km/s) spectra of interstellar Ca I absorption toward 30 Galactic stars. Comparisons of the column densities of Ca I, Ca II, K I, and other species -- for individual components identified in the line profiles and also when integrated over entire lines of sight -- yield information on relative electron densities and depletions. There is no obvious relationship between the ratio N(Ca I)/N(Ca II) [equal to n_e/(Gamma/alpha_r) for photoionization equilibrium] and the fraction of hydrogen in molecular form f(H2) (often taken to be indicative of the local density n_H). For a smaller sample of sightlines for which the thermal pressure (n_H T) and local density can be estimated via analysis of the C I fine-structure excitation, the average electron density inferred from C, Na, and K (assuming photoionization equilibrium) seems to be independent of n_H and n_H T. While the n_e obtained from the ratio N(Ca I)/N(Ca II) is often significantly higher than the values derived from other elements, the patterns of relative n_e derived from different elements show both similarities and differences for different lines of sight -- suggesting that additional processes besides photoionization and radiative recombination commonly and significantly affect the ionization balance of heavy elements in diffuse IS clouds. Such additional processes may also contribute to the (apparently) larger than expected fractional ionizations (n_e/n_H) found for some lines of sight with independent determinations of n_H. In general, inclusion of ``grain-assisted'' recombination does reduce the inferred n_e, but it does not reconcile the n_e estimated from different elements. The depletion of calcium may have a much weaker dependence on density than was suggested by earlier comparisons with CH and CN.Comment: aastex, 70 pages, accepted to ApJ

City of dreams

Higher ability workers benefit more from bigger cities while housing costs there are higher for everyone, and yet there is little sorting on ability. A possible explanation is that young individuals have an imperfect assessment of their ability, and, when they learn about it, early decisions have had a lasting impact and reduce their incentives to move. We formalize this idea through an overlapping generations model of urban sorting by workers with heterogenous ability and self-confidence, with the latter defined as individuals’ assessment of their own ability. We then test the location patterns predicted by the model over the life cycle on panel data from the National Longitudinal Survey of Youth 1979. We find that the city-size choices of individuals at different stages vary with ability and self-confidence in a way that closely matches our theoretical predictions

La responsabilidad de proteger

La controversia que emerge en torno a la R2P se inscribe en un cleavage presente a lo largo del tiempo (desde Hugo Grocio, a Bernard Kouchner pasando por Jean Henri Dunnant): Estados pluralistas (art. 2.7 de la Carta de NN.UU) y Estados solidaristas (art. 1.3 de la Carta de NN.UU). En el año 2001 emerge la R2P bajo liderazgo de Gareth Evans y de Mohamed Sahnoun en la comisión canadiense ICISS. Dicha norma busca conjugar los valores de pluralistas (intereses) y solidaristas (valores), y será aprobada durante de la Cumbre Mundial de NN.UU en 2005 sufriendo cambios dentro del debate pluralismo-solidarismo. Tras analizar el proceso de emergencia hacia la aceptación definitiva, también se aborda el debate normativo que ha surgido alrededor de la R2P. En él encontramos dos grande debates. El primero es el ideacional dónde encontramos la división entre Estados solidaristas y pluralistas, el segundo es el instrumental (ciclo de Finnermore y RWP). Finalmente, se analizan tres casos prácticos para poder determinar si dicha norma se encuentra internalizada en las estructuras burocráticas y sociales o no. La pauta que se lleva a cabo para su análisis se divide en tres puntos. El primero sobre causa justa se relaciona con el hecho de que se de alguno de los 4 crímenes de la R2P ; el segundo con la existencia o no de un mandato del Consejo de Seguridad de NNUU; y el tercero con la eficacia de la acción, es decir el respeto o no del mandato. Los casos analizados son los de Darfur (Sudán), Libia y Malí. No obstante, en ninguno de los tres casos se cumplen los 3 puntos necesarios para poder hablar de un uso correcto de la R2P. Por lo tanto la R2P no solamente ha sufrido desde su emergencia y aceptación una deriva hacia el pluralismo, sino que también su aplicación (internalización) incorrecta ha servido para enaltecer l os principios de la gestión de conflictos estatocéntrica basada en el respeto de la soberanía entre otros

Nonholonomic constraints in kk-symplectic Classical Field Theories

A $k$-symplectic framework for classical field theories subject to nonholonomic constraints is presented. If the constrained problem is regular one can construct a projection operator such that the solutions of the constrained problem are obtained by projecting the solutions of the free problem. Symmetries for the nonholonomic system are introduced and we show that for every such symmetry, there exist a nonholonomic momentum equation. The proposed formalism permits to introduce in a simple way many tools of nonholonomic mechanics to nonholonomic field theories.Comment: 27 page

Hamiltonian dynamics and constrained variational calculus: continuous and discrete settings

The aim of this paper is to study the relationship between Hamiltonian dynamics and constrained variational calculus. We describe both using the notion of Lagrangian submanifolds of convenient symplectic manifolds and using the so-called Tulczyjew's triples. The results are also extended to the case of discrete dynamics and nonholonomic mechanics. Interesting applications to geometrical integration of Hamiltonian systems are obtained.Comment: 33 page

Dynamics of a Massive Binary at Birth

Almost all massive stars have bound stellar companions, existing in binaries or higher-order multiples. While binarity is theorized to be an essential feature of how massive stars form, essentially all information about such properties is derived from observations of already formed stars, whose orbital properties may have evolved since birth. Little is known about binarity during formation stages. Here we report high angular resolution observations of 1.3 mm continuum and H30alpha recombination line emission, which reveal a massive protobinary with apparent separation of 180 au at the center of the massive star-forming region IRAS07299-1651. From the line-of-sight velocity difference of 9.5 km/s of the two protostars, the binary is estimated to have a minimum total mass of 18 solar masses, consistent with several other metrics, and maximum period of 570 years, assuming a circular orbit. The H30alpha line from the primary protostar shows kinematics consistent with rotation along a ring of radius of 12 au. The observations indicate that disk fragmentation at several hundred au may have formed the binary, and much smaller disks are feeding the individual protostars.Comment: Published in Nature Astronomy. This is author's version. Full article is available here (https://rdcu.be/brENk). 47 pages, 10 figures, including methods and supplementary informatio

La restricción presupuestaria blanda de las Comunidades Autónomas

Se revisa la literatura, en inglés y en castellano, sobre la Restricción Presupuestaria Blanda, corresponsabilidad fiscal, descentralización fiscal, etc. Seguidamente, y según la literatura revisada, se realiza un acercamiento a los datos de la situación relativa a España y las Comunidades Autónomas para, vista la literatura y los resultados obtenidos, realizar un estudio econométrico acerca de la evolución de la restricción presupuestaria blanda de las CCAA para el caso español así como de los posibles factores que incentivan la generación de la mismaEs revisa la literatura, en anglès i en castellà, sobre la Restricció Pressupostària Tova, corresponsabilitat fiscal, descentralització fiscal, etc. Seguidament, i segons la literatura revisada, es realitza apropament a los dades de la situació relativa a Espanya i les Comunitats Autònomes per tal de, vista la literatura i els reultats obstinguts, realizar un estudi economètric sobre la evolució de la Restricció Pressupostària Tova de les CCAA per al cas español, així com dels possiobles factors que incentiven la generació de la mateix

Nuevos datos sobre el género Tulostoma (Gasteromycetes) en España. IV

Eleven taxa of Tulostoma are mentioned in this article, from which T crassipes represents a new record for Spain and T aff. bruchi is mentioned for the second time. Other common species such as T brumale, T caespitosum, T cyclophorum, T fimbriatum, T giovanellae, T kotlabae, T lloydii, T subsquamosum and T squamosum are recorded in new localities, too.Se mencionan once taxones de Tulostoma en este artículo, entre los cuales destaca T crassipes como especie nueva para España y T aff. bruchi que se cita por segunda vez. Ademas, se aportan datos nuevos sobre la distribución geografica de otros taxones frecuentes, tales como: T brum a/e, T caespitosum, T cyclophorum, T fimbriatum, T giovanellae, T kotlabae, T lloydii, T squamosum y T subsquamosu

Climate change education at first sustainable public school : a case study

This case study is focused on the first sustainable and self-sufficient public school in Latin America -and arguably the world-, School No.294 in Jaureguiberry, Uruguay. This research studied how the Climate Change Education (CCE) policies and practices carried out in the school have been interpreted by the school community. This qualitative study had two research questions: 1. How have the educational team, parents and students interpreted and adopted the CCE policies and practices of the school and how have they reacted in their own practice? 2. What personal and contextual circumstances can explain the different interpretations and reactions to the climate change education policy among the school community? Data was collected through interviews and document analysis; 17 participants took part of this study and 6 documents were analysed. The semi-structured online interviews were conducted between November 2020 and March 2021. Findings indicate that the community has had a mixed reception to the CCE policies and practices. For instance, at the start of the school project in 2016, only 15% of families had an organic vegetable garden at home whereas in 2019, 80% of families did. On the other hand, only a few members of the community actively participate and support school activities. Moreover, there have been tensions between and within actors. The active and sustainability-oriented pedagogical approach was defined as 'transformative education for sustainability', and enablers and barriers were identified. The findings of this study highlight how important the support of the community and authorities can be for climate change education projects