New fully evolutionary models for asteroseismology of ultra-massive white dwarf stars

Ultra-massive hydrogen-rich (DA spectral type) white dwarf (WD) stars ($M_{\star} > 1M_{\odot}$) coming from single-star evolution are expected to harbor cores made of $^{16}$O and $^{20}$Ne, resulting from semi-degenerate carbon burning when the progenitor star evolves through the super asymptotic giant branch (S-AGB) phase. These stars are expected to be crystallized by the time they reach the ZZ Ceti instability strip ($T_{\rm eff} \sim 12\,500$ K). Theoretical models predict that crystallization leads to a separation of $^{16}$O and $^{20}$Ne in the core of ultra-massive WDs, which impacts their pulsational properties. This property offers a unique opportunity to study the processes of crystallization. Here, we present the first results of a detailed asteroseismic analysis of the best-studied ultra-massive ZZ Ceti star BPM~37093. As a second step, we plan to repeat this analysis using ultra-massive DA WD models with C/O cores in order to study the possibility of elucidating the core chemical composition of BPM~37093 and shed some light on its possible evolutionary origin. We also plan to extend this kind of analyses to other stars observed from the ground and also from space missions like Kepler and TESS.Comment: 4 pages, 2 tables, 2 figures, poster contribution at the conference "Stars and their variability observed from space - Celebrating the 5th anniversary of BRITE-Constellation", Vienna, Austria, August 19 - 23, 2019. Eds: C. Neiner, W. Weiss, D. Baade, E. Griffin, C. Lovekin, A. Moffa

Asteroseismological analysis of the polluted ZZ Ceti star G29-38 with TESS

G\,29$-$38 (TIC~422526868) is one of the brightest ($V=13.1$) and closest ($d = 17.51$\,pc) pulsating white dwarfs with a hydrogen-rich atmosphere (DAV/ZZ Ceti class). It was observed by the {\sl TESS} spacecraft in sectors 42 and 56. The atmosphere of G~29$-$38 is polluted by heavy elements that are expected to sink out of visible layers on short timescales. The photometric {\sl TESS} data set spans $\sim 51$ days in total, and from this, we identified 56 significant pulsation frequencies, that include rotational frequency multiplets. In addition, we identified 30 combination frequencies in each sector. The oscillation frequencies that we found are associated with $g$-mode pulsations, with periods spanning from $\sim$ 260 s to $\sim$ 1400 s. We identified %three distinct rotational frequency triplets with a mean separation $\delta \nu_{\ell=1}$ of 4.67 $\mu$Hz and a quintuplet with a mean separation $\delta \nu_{\ell=2}$ of 6.67 $\mu$Hz, from which we estimated a rotation period of about $1.35 \pm 0.1$ days. We determined a constant period spacing of 41.20~s for $\ell= 1$ modes and 22.58\,s for $\ell= 2$ modes. We performed period-to-period fit analyses and found an asteroseismological model with $M_{\star}/M_{\odot}=0.632 \pm 0.03$, $T_{\rm eff}=11\, 635\pm 178$ K, and $\log{g}=8.048\pm0.005$ (with a hydrogen envelope mass of $M_{\rm H}\sim 5.6\times 10^{-5}M_{\star}$), in good agreement with the values derived from spectroscopy. We obtained an asteroseismic distance of 17.54 pc, which is in excellent agreement with that provided by {\sl Gaia} (17.51 pc).Comment: 17 pages, Accepted for publication in MNRA

Probing the Structure of Kepler ZZ Ceti Stars with Full Evolutionary Models-based Asteroseismology

We present an asteroseismological analysis of four ZZ Ceti stars observed with the Kepler spacecraft: GD 1212, SDSS J113655.17+040952.6, KIC 11911480, and KIC 4552982, based on a grid of full evolutionary models of DA white dwarf (WD) stars. We employ a grid of carbon–oxygen core models, characterized by a detailed and consistent chemical inner profile for the core and the envelope. In addition to the observed periods, we take into account other information from the observational data, such as amplitudes, rotational splittings, and period spacing, as well as photometry and spectroscopy. For each star, we present an asteroseismological model that closely reproduces their observed properties. The asteroseismological stellar mass and effective temperature of the target stars are (0.632 0.027 ± M☉, 10737 ± 73 K) for GD 1212, (0.745 0.007 ± M☉, 11110 ± 69 K) for KIC 4552982, (0.5480 0.01 ± M☉, 12,721 ± 228 K) for KIC11911480, and (0.570 0.01 ± M☉, 12,060 ± 300 K) for SDSS J113655.17+040952.6. In general, the asteroseismological values are in good agreement with the spectroscopy. For KIC 11911480 and SDSS J113655.17+040952.6 we derive a similar seismological mass, but the hydrogen envelope is an order of magnitude thinner for SDSS J113655.17+040952.6, which is part of a binary system and went through a common envelope phase

Yatichiriru Yatichaña Aymara Aru Kamachi = Gramática pedagógica Aimara

Esta gramática, al igual que el manual de escritura (que incluye las orientaciones para el uso del alfabeto), permite a los y las docentes de EIB conocer más su lengua originaria, tener a mano normas de escritura consensuadas y avanzar en la construcción de estilos escritos que se vayan estandarizando por acción de los hablantes de esta lengua originaria. Todo esto es necesario para desarrollar la propuesta pedagógica de educación intercultural bilingüe y promover competencias comunicativas en la lengua originaria. Esta publicación fue elaborada por lingüistas expertos en el estudio de la gramática de esta lengua originaria y docentes bilingües que hablan y escriben competentemente en dicha lengua. Una primera versión acabada de esta gramática fue presentada a sabias y sabios, representantes de organizaciones indígenas, especialistas de educación intercultural bilingüe, para recoger sus sugerencias y observaciones que permitieron realizar la validación del material

Com o diabo no corpo: os terríveis papagaios do Brasil colônia

Desde a Antiguidade, papagaios, periquitos e afins (Psittacidae) fascinaram os europeus por seu vivo colorido e uma notável capacidade de interação com seres humanos. A descoberta do Novo Mundo nada faria além de acrescentar novos elementos ao tráfico de animais exóticos há muito estabelecido pelos europeus com a África e o Oriente. Sem possuir grandes mamíferos, a América tropical participaria desse comércio com o que tinha de mais atrativo, essencialmente felinos, primatas e aves - em particular os papagaios, os quais eram embarcados em bom número. Contudo, a julgar pelos documentos do Brasil colônia, esses voláteis podiam inspirar muito pouca simpatia, pois nenhum outro animal - exceto as formigas - foi tantas vezes mencionado como praga para a agricultura. Além disso, alguns psitácidas mostravam-se tão loquazes que inspiravam a séria desconfiança de serem animais demoníacos ou possessos, pois só três classes de entidades - anjos, homens e demônios - possuíam o dom da palavra. Nos dias de hoje, vários representantes dos Psittacidae ainda constituem uma ameaça para a agricultura, enquanto os indivíduos muito faladores continuam despertando a suspeita de estarem possuídos pelo demônio. Transcendendo a mera curiosidade, essa crença exemplifica o quão intrincadas podem ser as relações do homem com o chamado “mundo natural”, revelando um universo mais amplo e multifacetado do que se poderia supor a princípio. Nesse sentido, a existência de aves capazes de falar torna essa relação ainda mais complexa e evidencia que as dificuldades de estabelecer o limite entre o animal e o humano se estendem além dos primatas e envolvem as mais inusitadas espécies zoológicas.Since ancient times, parrots and their allies (Psittacidae) have fascinated Europeans by their striking colors and notable ability to interact with human beings. The discovery of the New World added new species to the international exotic animal trade, which for many centuries had brought beasts to Europe from Africa and the Orient. Lacking large mammals, tropical America participated in this trade with its most appealing species, essentially felines, primates and birds - especially parrots - which were shipped in large numbers. It should be noted, however, that at times these birds were not well liked. In fact, according to documents from colonial Brazil, only the ants rank higher than parrots as the animals most often mentioned as agricultural pests. On the other hand, some of these birds were so chatty that people suspected them to be demonic or possessed animals, since only three classes of beings - angels, men and demons - have the ability to speak. Nowadays, several Psittacidae still constitute a threat to agriculture, and the suspicion that extremely talkative birds were demon possessed has also survived. More than a joke or a mere curiosity, this belief exemplifies how intricate man’s relationships with the “natural world” may be. In this sense, the existence of birds that are able to speak adds a further twist to these relationships, demonstrating that the problem of establishing a boundary between the animal and the human does not only involve primates, but also includes some unusual zoological species

Tratamiento aseptico en las quemaduras : Tesis presentada para optar al grado de doctor en medicina

A la cabeza de portada: Universidad Nacional de Buenos Aires. Facultad de Ciencias Médicas. - Incluye nómina de Catedráticos y Asignaturas. Tesis con dedicatoria

México y Estados Unidos: Amenazas y oportunidades que surgen con la renegociación del TLCAN

El Tratado de Libre Comercio de América del Norte ha creado una de las áreas comerciales más grandes en el mundo. Para México, este tratado, en vigor desde 1994, representa un factor de crecimiento económico y de exportaciones, convirtiendo a Estados Unidos en su principal socio comercial. A raíz del gobierno del presidente Donald Trump, sin embargo, se ha generado un período de incertidumbre por la renegociación y posible eliminación del referido tratado, decisión que pondría en riesgo el auge económico mexicano y afectarían las relaciones entre México, Estados Unidos y Canadá. La investigación analiza el impacto económico del TLCAN, con el objetivo de determinar las amenazas y oportunidades que tendrá que asumir México para continuar su crecimiento económico en caso se elimine el tratado. El estudio se desarrolla mediante el método de investigación cualitativa apoyada por datos secundarios. Recurre a la observación, la revisión bibliográfica y las entrevistas especializadas, tanto a personalidades del área empresarial como del campo investigativo, para describir y analizar el objeto de estudio. Entre sus principales conclusiones la investigación establece que la amenaza más grave de la eliminación del acuerdo comercial será la inestabilidad en la economía mexicana, así como la incertidumbre en el exterior respecto a las relaciones diplomáticas, políticas y comerciales con Estados Unidos, lo que podría generar la salida de inversión extranjera directa del país y una importante reducción en las exportacionesThe North American Free Trade Agreement (NAFTA) has created one of the largest commercial areas in the world. For Mexico, this treaty, which has been in effect since 1994, represents an important factor of economic growth and exports, in which the United States is its main trading partner. Since the beginning of the government of President Donald Trump, there has been a period of uncertainty concerning the renegotiation and the possibility of eliminating the treaty, a possibility that has put in risk both the economic boom and relations between Mexico, the United States and Canada. This research analyzes the economic impact of NAFTA, with the objective of determining some of the strategies that Mexico will have to assume to continue its economic growth should the treaty be eliminated. The study is developed using a qualitative method supported by secondary data. It uses observation, bibliographical revision and interviews, both to specialists of the research area in order to describe and analyze the subject of study. We arrive to the conclusion that in the future, if the treaty is affected, it will result in economic instability in México, and tensions in its political and economic relations with the United States which will result in the decline of foreign direct investment in the country and a significant reduction in exports

Toda la dificultad de este negocio consiste en aueriguar si d. Geronimo de Caparroso, puesto que esta en un mismo grado co[n] doña Esperança de Soria, la ha de preferir por varon en este mayorazgo .

Probablemente impreso en el S. XVII.Sign.: A-C\ps2\s.Texto a línea tirada con reclamos.Hojas impresas por ambas caras