La guerra de los Estados Unidos contra la inmigración. Efectos paradójicos

A finales de la década de 1950, Estados Unidos permitía la entrada de aproximadamente medio millón de inmigrantes mexicanos al año, de los cuales 450.000 llegaban con visados de trabajo temporal y 50.000 lo hacían con visados de residentes permanentes. A mediados de la década de 1960, los cambios en la política migratoria de Estados Unidos realizados en nombre de los derechos civiles redujeron drásticamente las oportunidades de entrada legal en el país. Se eliminaron los visados de trabajo temporal y se limitaron los visados de residentes a 20.000 por año. Con las oportunidades de entrada legal restringidas, los flujos migratorios ya establecidos simplemente continuaron fuera de los límites legales, lo cual dio comienzo a una inesperada reacción en cadena de eventos que culminaron en una guerra total contra los inmigrantes y el rápido crecimiento -sin precedentes- de población residente no autorizada en Estados Unidos. El presente artículo demuestra que el aumento de inmigración indocumentada en los Estados Unidos y el incremento de la población sin papeles son un producto de políticas migratorias y fronterizas mal concebidas.A finals de la dècada de 1950, els Estats Units permetien l'entrada d'aproximadament mig milió d'immigrants mexicans l'any, dels quals 450.000 hi arribaven amb visats de treball temporal i 50.000 ho feien amb visats de residents permanents. A mitjan anys seixanta, els canvis en la política migratòria dels Estats Units realitzats en nom dels drets civils van reduir dràsticament les oportunitats d'entrada legal al país. Es van eliminar els visats de treball temporal i es van limitar els visats de residents a 20.000 per any. Amb les oportunitats d'entrada legal restringides, els fluxos migratoris ja establerts simplement van continuar fora dels límits legals, la qual cosa va donar lloc a una inesperada reacció en cadena d'esdeveniments que van culminar en una guerra total contra les persones immigrants i el creixement ràpid -sense precedents- de població resident no autoritzada als Estats Units. El present article demostra que l'augment d'immigració indocumentada als Estats Units i l'increment de població sense papers són un producte de polítiques migratòries i frontereres mal concebudes

The United States war against immigration: Paradoxical effects

A finals de la dècada de 1950, els Estats Units permetien l’entrada d’aproximadament mig milió d’immigrants mexicans l’any, dels quals 450.000 hi arribaven amb visats de treball temporal i 50.000 ho feien amb visats de residents permanents. A mitjan anys seixanta, els canvis en la política migratòria dels Estats Units realitzats en nom dels drets civils van reduir dràsticament les oportunitats d’entrada legal al país. Es van eliminar els visats de treball temporal i es van limitar els visats de residents a 20.000 per any. Amb les oportunitats d’entrada legal restringides, els fluxos migratoris ja establerts simplement van continuar fora dels límits legals, la qual cosa va donar lloc a una inesperada reacció en cadena d’esdeveniments que van culminar en una guerra total contra les persones immigrants i el creixement ràpid —sense precedents— de població resident no autoritzada als Estats Units. El present article demostra que l’augment d’immigració indocumentada als Estats Units i l’increment de població sense papers són un producte de polítiques migratòries i frontereres mal concebudes.A finales de la década de 1950, Estados Unidos permitía la entrada de aproximadamente medio millón de inmigrantes mexicanos al año, de los cuales 450.000 llegaban con visados de trabajo temporal y 50.000 lo hacían con visados de residentes permanentes. A mediados de la década de 1960, los cambios en la política migratoria de Estados Unidos realizados en nombre de los derechos civiles redujeron drásticamente las oportunidades de entrada legal en el país. Se eliminaron los visados de trabajo temporal y se limitaron los visados de residentes a 20.000 por año. Con las oportunidades de entrada legal restringidas, los flujos migratorios ya establecidos simplemente continuaron fuera de los límites legales, lo cual dio comienzo a una inesperada reacción en cadena de eventos que culminaron en una guerra total contra los inmigrantes y el rápido crecimiento —sin precedentes— de población residente no autorizada en Estados Unidos. El presente artículo demuestra que el aumento de inmigración indocumentada en los Estados Unidos y el incremento de la población sin papeles son un producto de políticas migratorias y fronterizas mal concebidas.At the end of the 1950s, the United States permitted the entry of a half million Mexican migrants per year, of which 450,000 entered with temporary work visas and 50,000 as permanent residents. By the mid-1970s, however, changes in U.S. migration policy undertaken in the name of civil rights had eliminated temporary work visas and limited legal resident visas to 20,000 per year. With the opportunities for legal entry curtailed, migratory flows simply re-established themselves under undocumented auspices, giving rise to a chain reaction that culminated in a new war on immigrants and the unprecedented growth of the unauthorized population of the United States. This article shows that the rise of undocumented migration and the growth of America’s undocumented population are a product of poorly conceived immigration and border policies

Understanding young people's transitions in university halls through space and time

This article contributes to the theoretical discussion about young people's transitions through space and time. Space and time are complex overarching concepts that have creative potential in deepening understanding of transition. The focus of this research is young people's experiences of communal living in university halls. It is argued that particular space-time concepts draw attention to different facets of experience and in combination deepen the understanding of young people's individual and collective transitions. The focus of the article is the uses of the space-time concepts 'routine', 'representation', 'rhythm' and 'ritual' to research young people's experiences. The article draws on research findings from two studies in the North of England. © 2010 SAGE Publications

TESS hunt for young and maturing exoplanets (THYME). III. A two-planet system in the 400 Myr Ursa major group

A.W.M. was supported through NASA's Astrophysics Data Analysis Program (80NSSC19K0583). M.L.W. was supported by a grant through NASA's K2 GO program (80NSSC19K0097). This material is based on work supported by the National Science Foundation Graduate Research Fellowship Program under grant No. DGE-1650116 to P.C.T. A.V.'s work was performed under contract with the California Institute of Technology/Jet Propulsion Laboratory funded by NASA through the Sagan Fellowship Program executed by the NASA Exoplanet Science Institute. D.D. acknowledges support from NASA through Caltech/JPL grant RSA-1006130 and through the TESS Guest Investigator Program grant 80NSSC19K1727.Exoplanets can evolve significantly between birth and maturity, as their atmospheres, orbits, and structures are shaped by their environment. Young planets (<1 Gyr) offer an opportunity to probe the critical early stages of this evolution, where planets evolve the fastest. However, most of the known young planets orbit prohibitively faint stars. We present the discovery of two planets transiting HD 63433 (TOI 1726, TIC 130181866), a young Sun-like (M∗=0.99±0.03) star. Through kinematics, lithium abundance, and rotation, we confirm that HD 63433 is a member of the Ursa Major moving group (τ=414±23 Myr). Based on the TESS light curve and updated stellar parameters, we estimate the planet radii are 2.15±0.10R⊕ and 2.67±0.12R⊕, the orbital periods are 7.11 and 20.55 days, and the orbital eccentricities are lower than about 0.2. Using HARPS-N velocities, we measure the Rossiter-McLaughlin signal of the inner planet, demonstrating that the orbit is prograde. Since the host star is bright (V=6.9), both planets are amenable to transmission spectroscopy, radial velocity measurements of their masses, and more precise determination of the stellar obliquity. This system is therefore poised to play an important role in our understanding of planetary system evolution in the first billion years after formation.PostprintPeer reviewe

The Magellan-TESS Survey I: Survey Description and Mid-Survey Results

One of the most significant revelations from Kepler is that roughly one-third of Sun-like stars host planets which orbit their stars within 100 days and are between the size of Earth and Neptune. How do these super-Earth and sub-Neptune planets form, what are they made of, and do they represent a continuous population or naturally divide into separate groups? Measuring their masses and thus bulk densities can help address these questions of their origin and composition. To that end, we began the Magellan-TESS Survey (MTS), which uses Magellan II/PFS to obtain radial velocity (RV) masses of 30 transiting exoplanets discovered by TESS and develops an analysis framework that connects observed planet distributions to underlying populations. In the past, RV measurements of small planets have been challenging to obtain due to the faintness and low RV semi-amplitudes of most Kepler systems, and challenging to interpret due to the potential biases in the existing ensemble of small planet masses from non-algorithmic decisions for target selection and observation plans. The MTS attempts to minimize these biases by focusing on bright TESS targets and employing a quantitative selection function and multi-year observing strategy. In this paper, we (1) describe the motivation and survey strategy behind the MTS, (2) present our first catalog of planet mass and density constraints for 25 TESS Objects of Interest (TOIs; 20 in our population analysis sample, five that are members of the same systems), and (3) employ a hierarchical Bayesian model to produce preliminary constraints on the mass-radius (M-R) relation. We find qualitative agreement with prior mass-radius relations but some quantitative differences (abridged). The the results of this work can inform more detailed studies of individual systems and offer a framework that can be applied to future RV surveys with the goal of population inferences.Comment: 101 pages (39 of main text and references, the rest an appendix of figures and tables). Submitted to AAS Journal

A second planet transiting LTT 1445A and a determination of the masses of both worlds

K.H. acknowledges support from STFC grant ST/R000824/1.LTT 1445 is a hierarchical triple M-dwarf star system located at a distance of 6.86 pc. The primary star LTT 1445A (0.257 M⊙) is known to host the transiting planet LTT 1445Ab with an orbital period of 5.36 days, making it the second-closest known transiting exoplanet system, and the closest one for which the host is an M dwarf. Using Transiting Exoplanet Survey Satellite data, we present the discovery of a second planet in the LTT 1445 system, with an orbital period of 3.12 days. We combine radial-velocity measurements obtained from the five spectrographs, Echelle Spectrograph for Rocky Exoplanets and Stable Spectroscopic Observations, High Accuracy Radial Velocity Planet Searcher, High-Resolution Echelle Spectrometer, MAROON-X, and Planet Finder Spectrograph to establish that the new world also orbits LTT 1445A. We determine the mass and radius of LTT 1445Ab to be 2.87 ± 0.25 M⊕ and 1.304-0.060+0.067 R⊕, consistent with an Earth-like composition. For the newly discovered LTT 1445Ac, we measure a mass of 1.54-0.19+0.20 M⊕ and a minimum radius of 1.15 R⊕, but we cannot determine the radius directly as the signal-to-noise ratio of our light curve permits both grazing and nongrazing configurations. Using MEarth photometry and ground-based spectroscopy, we establish that star C (0.161 M⊙) is likely the source of the 1.4 day rotation period, and star B (0.215 M⊙) has a likely rotation period of 6.7 days. We estimate a probable rotation period of 85 days for LTT 1445A. Thus, this triple M-dwarf system appears to be in a special evolutionary stage where the most massive M dwarf has spun down, the intermediate mass M dwarf is in the process of spinning down, while the least massive stellar component has not yet begun to spin down.Publisher PDFPeer reviewe

The TESS Grand Unified Hot Jupiter Survey. II. Twenty New Giant Planets

NASA's Transiting Exoplanet Survey Satellite (TESS) mission promises to improve our understanding of hot Jupiters by providing an all-sky, magnitude-limited sample of transiting hot Jupiters suitable for population studies. Assembling such a sample requires confirming hundreds of planet candidates with additional follow-up observations. Here, we present twenty hot Jupiters that were detected using TESS data and confirmed to be planets through photometric, spectroscopic, and imaging observations coordinated by the TESS Follow-up Observing Program (TFOP). These twenty planets have orbital periods shorter than 7 days and orbit relatively bright FGK stars ($10.9 < G < 13.0$). Most of the planets are comparable in mass to Jupiter, although there are four planets with masses less than that of Saturn. TOI-3976 b, the longest period planet in our sample ($P = 6.6$ days), may be on a moderately eccentric orbit ($e = 0.18\pm0.06$), while observations of the other targets are consistent with them being on circular orbits. We measured the projected stellar obliquity of TOI-1937A b, a hot Jupiter on a 22.4 hour orbit with the Rossiter-McLaughlin effect, finding the planet's orbit to be well-aligned with the stellar spin axis ($|\lambda| = 4.0\pm3.5^\circ$). We also investigated the possibility that TOI-1937 is a member of the NGC 2516 open cluster, but ultimately found the evidence for cluster membership to be ambiguous. These objects are part of a larger effort to build a complete sample of hot Jupiters to be used for future demographic and detailed characterization work.Comment: 67 pages, 11 tables, 13 figures, 2 figure sets. Resubmitted to ApJS after revision