Anti-strange meson-baryon interaction in hot and dense nuclear matter

We present a study of in-medium cross sections and (off-shell) transition rates for the most relevant binary reactions for strange pseudoscalar meson production close to threshold in heavy-ion collisions at FAIR energies. Our results rely on a chiral unitary approach in coupled channels which incorporates the $s$- and $p$-waves of the kaon-nucleon interaction. The formalism, which is modified in the hot and dense medium to account for Pauli blocking effects, mean-field binding on baryons, and pion and kaon self-energies, has been improved to implement full unitarization and self-consistency for both the $s$- and $p$-wave interactions at finite temperature and density. This gives access to in-medium amplitudes in several elastic and inelastic coupled channels with strangeness content $S=-1$. The obtained total cross sections mostly reflect the fate of the $\Lambda(1405)$ resonance, which melts in the nuclear environment, whereas the off-shell transition probabilities are also sensitive to the in-medium properties of the hyperons excited in the $p$-wave amplitudes [$\Lambda$, $\Sigma$ and $\Sigma^*(1385)$]. The single-particle potentials of these hyperons at finite momentum, density and temperature are also discussed in connection with the pertinent scattering amplitudes. Our results are the basis for future implementations in microscopic transport approaches accounting for off-shell dynamics of strangeness production in nucleus-nucleus collisions.Comment: 33 pages, 7 figures; enhanced discussion in Sec. 3; order of presentation of results modified in Sec. 4; updated reference list; corrected typos and wording; version to match publication in Phys. Rev.

Strange meson-baryon interaction in hot and dense medium: recent progress for a road to GSI/FAIR

We report recent results on the dynamics of strange hadrons in two-body reactions relevant for near-threshold production in heavy-ion collisions at GSI/FAIR and NICA-Dubna. In particular, $\bar K N$ scattering in hot and dense nuclear matter is studied within a chiral unitary framework in coupled channels, setting up the starting point for implementations in microscopic off-shell transport approaches. We focus on the calculation of transition rates with special attention to the excitation of hyperon resonances and isospin effects. Additionally, we explore "unconventional" strangeness generation by meson-meson and meson-baryon interactions in connection with recent HADES observations of deep sub-threshold $\phi$ and $\Xi$ production.Comment: 4 pages, 2 figures. To be published in the Proceedings of the 15th International Conference on Strangeness in Quark Matter (SQM2015), 6-11 July 2015, JINR, Dubna, Russi

Transport properties of bottomed mesons in a hot mesonic gas

In this work we evaluate the B-meson drag and diffusion coefficients in a hot medium constituted of light mesons (pions, kaons and eta mesons). We treat the B-meson and B*-meson interaction with pseudo-Goldstone bosons in chiral perturbation theory at next-to-leading order within the constraints from heavy quark symmetry, and employ standard unitarization techniques of NLO amplitudes in order to account for dynamically generated resonances (leading to a more efficient heavy-flavor diffusion) and thus reach higher temperatures. We estimate individual meson contributions from the gas to the transport coefficients and perform a comparison with other findings in literature. We report a bottom relaxation length of about 80 fm at a temperature of 150 MeV and for typical momenta of 1 GeV, at which our approach is reliable. Compared to a charm relaxation length of 40 fm in the same conditions, we conclude that the B mesons provide a cleaner probe of the early stages of a heavy-ion collision.Comment: 14 pages, 16 figures, 3 tables. Version published in Phys.Rev.D87, 034019 (2013). Only minor improvements with respect to v1: corrected typos, further clarifications and updated reference

Time-Restricted Feeding Extends Longevity in Drosophila Melanogaster

Time-restricted feeding (TRF) is a dietary intervention in which daily feeding patterns align with behavioral patterns, synchronizing feeding times with periods of higher activity, e.g. humans eating only during the day or rodents (nocturnal animals) at night. TRF has been shown to improve cardiac health in Drosophila melanogaster, reduce metabolic markers in rodent models, and reduce glycemic indices in prediabetic men. However, the mechanism and long-term effects of this intervention remain elusive. To understand the effect of TRF on longevity we used the fruit fly Drosophila melanogaster, which is a useful model for longevity, sleep and circadian studies because of its wellestablished sleep behavior, tractable genetics, and short lifespan. We found that TRF extends longevity of fruit flies only in mated females, while showing no effect on mated males or virgin females. We measured the amount of food consumed by flies on TRF and confirmed that TRF does not act through caloric restriction, which has been previously shown to extend longevity. Remarkably, animals undergoing TRF eat more, yet have lower body weight in comparison to animals on constant food. TRF-mediated lifespan extension is dependent on the molecular clock, as arrhythmic clock mutants fail to respond to TRF under light-dark conditions, suggesting that TRF may act as a zeitgeber to improve the animals’ health by coordinating activity patterns with food availability. In addition to its effect on wild-type animals, TRF also improves longevity in animals with reduced lifespan, such as sleep mutants. Further studies show that TRF changes the sleep architecture of wild-type females by increasing the amount of day sleep, while also promoting integrity of the blood-brain barrier. TRF life-extension effects show that this dietary intervention has potential to reveal a deeper understanding of the biology of ageing and how it interacts with feeding and circadian rhythms, placing a larger emphasis on time of intake rather than calories

Optimal Crop-Insurance Strategies under Climate Variability: Contrasting Insurer and Farmer Interests

This study analyzes the potential synergies and conflicts of interest between farmers and insurers in the selection of an optimal crop insurance contract. Special attention is given to how climate information influences this decision-making process. To do so, we consider a representative 40 hectares, rainfed, cotton-peanut farm located in Jackson County in Florida. Our results show that year-to-year ENSO-based climate variability affects farmers income and insurers gains according to crop insurance contracts. Additionally, introduction of ENSO-based climate forecasts presents a significant impact on the selection of a particular contract. We conclude that insurers and farmers can bridge their divergent interests by improving their understanding of the effect of climate conditions on the development of sustainable business plans.Environmental Economics and Policy, Risk and Uncertainty,

Conflictos socioambientales, derechos de los pueblos indígenas, nativos y comunidades campesinas

Antes de tratar el tema es necesario hacer una serie de precisiones acerca de los conceptos de “pueblo”, “indígenas”, “nativos” y “comunidades campesinas”. Pueblo proviene del latín populus, que tienen varios significados pero para nuestros efectos hace referencia a los habitantes de cierta región, nación o país, estos constituyen una comunidad que comparte una misma cultura. Indígena, es un término relativo a la población originaria de un territorio; pueblo indígena, por lo tanto, está vinculada a una comunidad originaria de una cierta región. En América del Sur, por ejemplo, encontramos a los aymara, los guaraníes, los mapuches, los incas y los aztecas estos fueron pueblos indígenas que existieron e incluso sus descendientes aún existen a lo largo y ancho del territorio americano. Por lo tanto cuando hablamos de pueblos indígenas nos estamos refiriendo a las sociedades precoloniales, estas poblaciones suelen anteceder al desarrollo del Estado moderno, generalmente regidos por normas legales, políticas, económicas, creencias religiosas y culturales de tipo europeo, producto de la colonización que enfrentaron

The Effect of Traditional Practices in the Efficiency of Dairy Farms in Wisconsin

The US dairy sector is facing structural changes including a geographical shift in dairy production and a tendency towards the implementation of more intensive production systems. These changes might significantly affect farm efficiency, profitability and the long-term economic sustainability of the dairy sector, especially in more traditional dairy production areas. Consequently, the goal of this study was to examine the impact of practices commonly used by dairy farmers and the effect of intensification on the performance of the farms. We used a sample of 273 Wisconsin dairy farms to estimate a stochastic production frontier simultaneously with a technical inefficiency model. The empirical analysis showed that at a commercial level the administration of bovine somatotropin hormone to lactating cows increases milk production. In addition, we found that production exhibits constant returns to scale and that farm efficiency is positively related to farm intensification, the level of contribution of family labor in the farm activities, the use of a total mixed ration (TMR) feeding system and the milking frequency.Technical inefficiency, stochastic production frontier, intensification, Livestock Production/Industries, Productivity Analysis,

Nathaniel Hawthorne's Concept of the Romance Novel: An Analysis of 'The House of the Seven Gables'

American Romanticism is considered one of the most important periods in American literature. This movement focused on nationalism, imagination and individualism, and thus many writers created fictional stories with fantastic and imaginary elements. Nathaniel Hawthorne stands out as one of the most influential Romantic writers, as he developed the idea of the "romantic novel" as a different genre from the novel. It combined realism and fantastic elements, and one of the main representative works of this genre is Hawthorne's "The House of the Seven Gables". Throughout an analysis of this work, we will find how Hawthorne represented his concept of "romance" through symbolism and Gothic elements