Effect of Mitigation Measures on the Spreading of COVID-19 in Hard-Hit States

State government-mandated social distancing measures have helped to slow down the growth of the COVID-19 pandemic in the United States. Current predictive models of the development of COVID-19, especially after mitigation efforts, are largely based on extrapolating the data from other countries. Since most states enforced stay-at-home orders towards the end of March, their effect should be reflected in the death and infection counts at the end of April. Using the data available until April 25th, we investigate the change in the infection rate due to the mitigation efforts, and project death and infection counts until September, 2020, for some of the most heavily impacted states: New York, New Jersey, Michigan, Massachusetts, Illinois and Louisiana. We find that with the current mitigation efforts five of those six states reduce their reproduction number to a value less than one, stopping the exponential growth of the pandemic. We also projected different scenarios after the mitigation is relaxed. Analysis for other states can be found at https://covid19projection.org/.Comment: 8 pages, 6 figures, 2 table

Transition Temperature of a Magnetic Semiconductor with Angular Momentum j

We employ dynamical mean-field theory to identify the materials properties that optimize Tc for a generalized double-exchange (DE) model. We reach the surprising conclusion that Tc achieves a maximum when the band angular momentum j equals 3/2 and when the masses in the 1/2 and 3/2 sub-bands are equal. However, we also find that Tc is significantly reduced as the ratio of the masses decreases from one. Consequently, the search for dilute magnetic semiconductors (DMS) materials with high Tc should proceed on two fronts. In semiconductors with p bands, such as the currently studied Mn-doped Ge and GaAs semiconductors, Tc may be optimized by tuning the band masses through strain engineering or artificial nanostructures. On the other hand, semiconductors with s or d bands with nearly equal effective masses might prove to have higher Tc's than p-band materials with disparate effective masses.Comment: 5 pages, 4 figure

Los contratos en origen de temporada: mujeres marroquíes en la agricultura onubense

En los últimos años, más de 22.000 marroquíes han pasado por los campos de la provincia de Huelva (España), a través de lo que se conoce como contrataciones en origen de temporada. Esta formula de gestión transnacional del empleo ha sido enarbolada como modelo de migración legal y ordenada. No obstante, una mirada atenta revela las asimetrías de género y de desarrollo sobre las que se asienta, así como los recortes de derechos laborales a los que da lugar. En este artículo se examina la arquitectura que sostiene estos programas de contratación temporera entre España y Marruecos, así como las experiencias de algunas de estas migrantes en los campos onubensesIn the last years more than 22.000 moroccan women workers have passed through the fields of the province of Huelva (Spain), through what is known as temporary country origin contracts. This way of transnational management of the job creation has been promoted as a legal and organize model of migration. Nevertheless, a close attention reveals the asymmetry of gender and development, and also the reduction of labour rights that support this model. This article analyzes the supporting architecture of these programs of temporary contracting in Spain and Morocco, and also the experience of some of these migrant women in the fields of Huelva

The Boson-Hubbard Model on a Kagome Lattice with Sextic Ring-Exchange Terms

High order ring-exchange interactions are crucial for the study of quantum fluctuations on highly frustrated systems. We present the first exact quantum Monte Carlo study of a model of hard-core bosons with sixth order ring-exchange interactions on a two-dimensional kagome lattice. By using the Stochastic Green Function algorithm, we show that the system becomes unstable in the limit of large ring-exchange interactions. It undergoes a phase separation at all fillings, except at 1/3 and 2/3 fillings for which the superfluid density vanishes and an unusual mixed valence bond and charge density ordered solid is formed.Comment: 4 pages, 7 figure

Autonomía reproductiva de las mujeres y derecho penal. Una interpretación feminista de las recientes reformas penales en España

En este trabajo, tratamos de establecer desde la Filosofía del Derecho, y en concreto, desde la teoría jurídica feminista (MacKinnon, 1989; Smart, 1994; 2000), si el Derecho Penal español después de las reformas llevadas a cabo en el Código Penal por la Ley Orgánica 2/2010, de 3 de marzo, de salud sexual y reproductiva, y de la interrupción voluntaria del embarazo, y por la Ley Orgánica 5/2010, de 22 de junio, por la que se modifica la Ley Orgánica 10/1995, de 23 de noviembre, del Código Penal, tiene en cuenta y protege la autonomía reproductiva de las mujeres. Utilizando como instrumento de análisis el concepto de autonomía reproductiva que hemos elaborado a partir del concepto de libertad de Fernando Savater (siguiendo la senda marcada por la filosofía de Espinoza, Kant y Fromm), ponemos de manifiesto los lineamientos que, en relación con la autonomía reproductiva de las mujeres, se desprenden de las normas penales, y de la doctrina y de la jurisprudencia que las han interpretado, como son: la indefinición de la autonomía reproductiva de las mujeres, su infravaloración en relación a la autonomía sexual y su fusión con esta última, y finalmente, la percepción de la autonomía reproductiva de las mujeres como una cuestión de salud, lineamientos que constituyen formas sutiles de control de la autonomía reproductiva de las mujeres que el Derecho Penal español aún ejerce

What is the valence of Mn in Ga1−x_{1-x}Mnx_xN?

We investigate the current debate on the Mn valence in Ga$_{1-x}$Mn$_x$N, a diluted magnetic semiconductor (DMSs) with a potentially high Curie temperature. From a first-principles Wannier-function analysis, we unambiguously find the Mn valence to be close to $2+$ ($d^5$), but in a mixed spin configuration with average magnetic moments of 4$\mu_B$. By integrating out high-energy degrees of freedom differently, we further derive for the first time from first-principles two low-energy pictures that reflect the intrinsic dual nature of the doped holes in the DMS: 1) an effective $d^4$ picture ideal for local physics, and 2) an effective $d^5$ picture suitable for extended properties. In the latter, our results further reveal a few novel physical effects, and pave the way for future realistic studies of magnetism. Our study not only resolves one of the outstanding key controversies of the field, but also exemplifies the general need for multiple effective descriptions to account for the rich low-energy physics in many-body systems in general.Comment: 4 figure

Les stratégies pour légaliser la "gestation pour autrui". Une remise en question à partir de la dignité et l´autonomie reproductive des femmes

Cette communication analyse deux des stratégies qui sont utilisées dans les lois et les propositions de loi, dans la doctrine et dans la jurisprudence, aussi bien en Espagne que dans d´autres pays européens, à fin de légaliser et/ou légitimer la “gestation pour autrui”: d´une part, sa configuration contractuelle et d´autre part, son classement ou son lien avec certains droits déjà juridiquement reconnus. Et ce que les résultats de l´analyse mettent en évidence, surtout au travers de ces deux stratégies et de l´ambiguïté et du caractère contradictoire des termes, des concepts et des arguments qui supportent ces stratégies, c´est que la dignité et l´autonomie reproductive des femmes ne sont pas vraiment prises en compte.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec