Sex morphs and invasiveness of a fleshy-fruited tree in natural grasslands from Argentina

Invasiveness has usually been studied as a species-level attribute; nevertheless, phenotypic differences between individuals in a population can lead to significant variations in colonization ability. In this paper, we analyse the potential effects of sex morphs of Prunus mahaleb, a gynodioecius fleshy-fruited tree, on its invasiveness in natural grasslands in the southern Argentine Pampas. We assessed the abundance of both hermaphrodite and female plants and compared their fecundity, propagule size and germination response. We found that the females were less abundant in the invasive populations studied, apparently since the beginning of the colonization. However, our results demonstrated that at the present time females do not show any fecundity reduction, which clearly shows that P. mahaleb has established an effective interaction with generalist pollinators which compensates for the apparent disadvantage of females. Fruit set showed a wider range of variability over time in the females than in the hermaphrodites, which could be the consequence of greater susceptibility to changes in the activity of pollinators. We found no evidence of a female benefit due to reallocation of resources or better outcrossed progeny considering propagule size and germination. We discuss the relative importance of sex morphs and interactions at different stages of the invasion process.Fil: Amodeo, Martín Raúl. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Grupo de Estudios en Conservación y Manejo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Zalba, Sergio Martín. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Grupo de Estudios en Conservación y Manejo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Methanol detection in M82

We present a multilevel study of the emission of methanol, detected for the first time in this galaxy, and discuss the origin of its emission. The high observed methanol abundance of a few 10^-9 can only be explained if injection of methanol from dust grains is taken into account. While the overall [CH3OH]/[NH3] ratio is much larger than observed towards other starbursts, the dense high excitation component shows a similar value to that found in NGC 253 and Maffei 2. Our observations suggest the molecular material in M 82 to be formed by dense warm cores, shielded from the UV radiation and similar to the molecular clouds in other starbursts, surrounded by a less dense photodissociated halo. The dense warm cores are likely the location of recent and future star formation within M 82.Comment: Accepted for publication in A&A Letter

The effect of pension rules on retirement monetary incentives with an application to pension reforms in Spain

In this work we theoretically disentangle the effects of pension provisions on a variety of financial incentives to retirement, trying to reconcile them with some key Spanish retirement patterns. We find that the "average" individual, who is never affected by any cap of contributions or benefits, has weak incentives to retire early and strong incentives to retire at the normal retirement age. Alternatively, individuals at the bottom of the wage distribution have strong incentives to retire as early as possible, because ot the interaction between age-related penalties and the minimun pension. Both findings perfectly accommodate the retirement hazard of medium and low earners respectively. In contrast, high earners (those that have their contributions capped) despite having strong incentives to retire at the Early Retirement Age, do not do so. This is because, for those workers, financial incentives are not a good proxy for the marginal utility from working. Finally, we analyze the reasons behind the failure of the 1997 reform in improving the sustainability of the Spanish public pension system

A note on the Gauge Symmetries of Unimodular Gravity

The symmetries of Unimodular Gravity are clarified somewhat.Comment: 4 pages, v2: acknowledgments correcte

Photodissociation chemistry footprints in the Starburst galaxy NGC 253

We report the first detection of PDR molecular tracers, namely HOC+, and CO+, and confirm the detection of the also PDR tracer HCO towards the starburst galaxy NGC 253, claimed to be mainly dominated by shock heating and in an earlier stage of evolution than M 82, the prototypical extragalactic PDR. Our CO+ detection suffers from significant blending to a group of transitions of 13CH3OH, tentatively detected for the first time in the extragalactic interstellar medium. These species are efficiently formed in the highly UV irradiated outer layers of molecular clouds, as observed in the late stage nuclear starburst in M 82. The molecular abundance ratios we derive for these molecules are very similar to those found in M 82. This strongly supports the idea that these molecules are tracing the PDR component associated with the starburst in the nuclear region of NGC 253. A comparison with the predictions of chemical models for PDRs shows that the observed molecular ratios are tracing the outer layers of UV illuminated clouds up to two magnitudes of visual extinction. Chemical models, which include grain formation and photodissociation of HNCO, support the scenario of a photo-dominated chemistry as an explanation to the abundances of the observed species. From this comparison we conclude that the molecular clouds in NGC 253 are more massive and with larger column densities than those in M 82, as expected from the evolutionary stage of the starbursts in both galaxies.Comment: 32 pages, 4 figures, Published in Ap

"He was in no place and no place was in him": Edward Dahlberg's autobiographical fictions as an epistemology of sites

Edward Dahlberg‘s childhood, adolescence and youth, narratively fictionalized in two early autobiographical novels, Bottom Dogs (1930) and Flushing to Calvary (1932) is markedly and recurrently informed by the influence of urban sites and institutional spaces. As the article discusses, a number of these spaces are pivotal to the development of Dahlberg‘s autobiographical character Lorry, and can be productively read in terms of the Foucaldian heterotopia, while other sites, explicitly identified as metropolitan, are marginal to Lorry‘s autobiographical narrative, and yet serve to foreground the protagonist‘s absence from them in relevant ways. Finally, other spaces may epitomize a predominantly artificial nature, functioning as simulacra of experiences that Lorry undergoes but needs to cast out. Drawing on theoretical tenets related to space, site and place, as set out by Foucault, Baudrillard, Lefebvre, and others, in this article I will contend that a situated epistemological approach is essential in fruitfully reading Dahlberg‘s early fictions, and, ultimately, in understanding his quest for space in both biographical and artistic terms.La infancia, adolescencia y juventud de Edward Dahlberg, ficcionalizada a través de sus dos tempranas novelas autobiográficas, Bottom Dogs (1930) y Flushing to Calvary (1932), está muy determinada por la influencia de entornos urbanos y espacios institucionales. Algunos de estos espacios son esenciales para el desarrollo de Lorry, el protagonista autobiográfico de Dahlberg, y pueden ser interpretados en clave de heterotopia Foucaldiana. Otros lugares, expresamente identificados como espacios metropolitanos, marginales a la narrativa autobiográfica centrada en Lorry, resultan, sin embargo, extremadamente significativos para subrayar la ausencia del protagonista de los mismos. Además, otros entornos sirven para encarnar condiciones artificiales, proporcionando simulacros de vivencias que Lorry experimenta pero necesita luego desechar. Partiendo de nociones teóricas relativas a los conceptos de sitio y de espacialidad, desarrolladas por Foucault, Baudrillard y Lefebvre, entre otros, el presente artículo propone un análisis basado en una epistemología de ―situacionalidad‖ que permita una interpretación crítica fructífera de la obra iniciática de Dahlberg, y, en concreto, ilumine su obsesiva búsqueda de espacio(s), tanto en términos biográficos como literarios.Ministerio de Economía y Competitividad (España) FFI 2015-66767-PXunta de Galicia (Galicia, España) ED431D2017/1

Determinants of tourism destination competitiveness in the countries most visited by international tourists: Proposal of a synthetic index

Tourism destination competitiveness is a multidimensional concept that is widely studied in the academic literature, but multiple factors make its measurement a difficult task. In this article, we design a synthetic index to rank the 80 countries that attract the majority of international tourists by level of tourism competitiveness. In order to do this, we use all of the simple variables included in the 2017 Travel & Tourism Competitiveness Index, proposing a new methodology for the construction of this synthetic index, which it solves the problems of aggregation of variables expressed in different measures, arbitrary weighting and duplicity of information; issues that remain unresolved by the TTCI. Likewise, we analyse the most influential dimensions in tourism competitiveness. Air transport infrastructures, cultural resources and ICT readiness are the key dimensions that explain the main disparities.Funding Agency Spanish Ministry of Economy, Industry and Competitiveness State Research Agency (SRA) European Union (EU) ECO2017-86822-Rinfo:eu-repo/semantics/publishedVersio