A six-part collisional model of the main asteroid belt

In this work, we construct a new model for the collisional evolution of the main asteroid belt. Our goals are to test the scaling law of Benz and Asphaug (1999) and ascertain if it can be used for the whole belt. We want to find initial size-frequency distributions (SFDs) for the considered six parts of the belt (inner, middle, 'pristine', outer, Cybele zone, high-inclination region) and to verify if the number of synthetic asteroid families created during the simulation matches the number of observed families as well. We used new observational data from the WISE satellite (Masiero et al., 2011) to construct the observed SFDs. We simulate mutual collisions of asteroids with a modified version of the Boulder code (Morbidelli et al., 2009), where the results of hydrodynamic (SPH) simulations of Durda et al. (2007) and Benavidez et al. (2012) are included. Because material characteristics can significantly affect breakups, we created two models - for monolithic asteroids and for rubble-piles. To explain the observed SFDs in the size range D = 1 to 10 km we have to also account for dynamical depletion due to the Yarkovsky effect. The assumption of (purely) rubble-pile asteroids leads to a significantly worse fit to the observed data, so that we can conclude that majority of main-belt asteroids are rather monolithic. Our work may also serve as a motivation for further SPH simulations of disruptions of smaller targets (with a parent body size of the order of 1 km).Comment: Accepted for publication in Icaru

Lifted particles from the fast spinning primary of the Near-Earth Asteroid (65803) Didymos

An increasing number of Near Earth Asteroids (NEAs) in the range of a few hundred meters to a few kilometres in size have relatively high spin rates, from less than 4 h, down to $\sim$2.2 h, depending on spectral type. For some of these bodies, local acceleration near the equator may be directed outwards so that lift off of near-equatorial material is possible. In particular, this may be the case for asteroid Didymos, the primary of the (65803) Didymos binary system, which is the target of the DART (NASA) and Hera (ESA) space missions. The study of the dynamics of particles in such an environment has been carried out -- in the frame of the Hera mission and the EC-H2020 NEO-MAPP project -- according to the available shape model, known physical parameters and orbital information available before the DART impact. The presence of orbiting particles in the system is likely for most of the estimated range of values for mass and volume. The spatial mass density of ejected material is calculated for different particle sizes and at different heliocentric orbit epochs, revealing that large particles dominate the density distribution and that small particle abundance depends on observation epoch. Estimates of take off and landing areas on Didymos are also reported. Available estimates of the system mass and primary extents, after the DART mission, confirm that the main conclusions of this study are valid in the context of current knowledge

On the genesis of the Haumea system

The scenarios proposed in the literature for the genesis of the system formed by the dwarf planet 136108 Haumea, its two satellites and a group of some 10 bodies (the family) with semimajor axes, eccentricities and inclinations close to Haumea's values, are analysed against collisional, physical, dynamical and statistical arguments in order to assess their likelihood. All scenarios based on collisional events are reviewed under physical arguments and the corresponding formation probabilities in a collisional environment are evaluated according to the collisional evolution model alicandep. An alternative mechanism is proposed based on the potential possibility of (quasi-) independent origin of the family with respect to Haumea and its satellites. As a general conclusion the formation of the Haumea system is a low-probability event in the currently assumed frame for the evolution of the outer Solar system. However, it is possible that current knowledge is missing some key element in the whole story that may contribute to increase the odds for the formation of such a system.Facultad de Ciencias Astronómicas y Geofísica

Correlation of Clinical Symptoms with Temporal and Frontoparietal Lobe Response During an Auditory \u27Odball\u27 Task of Chronic and First Episode Schizophrenia Patients (N=190)

The disorder of schizophrenia is defined by the presence of positive and negative clinical symptoms. One of the hallmark positive symptoms is the presence of auditory hallucinations which have previously been studied to involve bilateral temporal lobe anamolies. Our study seeks to further define and potentially quantify these anamolies in temporal lobe response by looking at the correlation of clinical symptoms with temporal lobe activation. To accomplish this task we have subjected 22 first episode and 64 chronic patients along with 104 matched healthy controls to a functional MRI scan while undergoing an auditory oddball\u27 task. Analysis of this data is unique in the use of independent component analysis (ICA) via Matlab toolbox (GIFT). Results showed expected positive activation patterns for temporal lobe activity across all participants but revealed no statistically significant differences within patient populations (first episode (FE) vs. chronic) or between patients and matched healthy controls. We observed strong correlation coefficients for both patient groups as positive symptoms were negatively correlated to temporal lobe response (FE rho = -0.31, chronic rho = -0.20). Negative symptoms were positively correlated but only statistically significant for first episode patients (rho = +0.23). This data is consistent with other studies involving EEG recordings of P300 amplitude response. Finally, in analyzing frontoparietal (FP) lobe activation we showed statistically signficant activation differences between patients and controls. This result could potentially be used as a future diagnostic test. In addition, we uncovered another point of asymmetry in first episode patients whose right FP lobe showed a nearly two-fold correlation coefficient value versus the left FP lobe for negative symptoms. This unique asymmetry could offer a new area of focus for future researchers into the pathophysiology of schizophrenia.\u2

The CFEPS Kuiper Belt Survey: Strategy and Pre-survey Results

We present the data acquisition strategy and characterization procedures for the Canada-France Ecliptic Plane Survey (CFEPS), a sub-component of the Canada-France-Hawaii Telescope Legacy Survey. The survey began in early 2003 and as of summer 2005 has covered 430 square degrees of sky within a few degrees of the ecliptic. Moving objects beyond the orbit of Uranus are detected to a magnitude limit of $m_R$=23 -- 24 (depending on the image quality). To track as large a sample as possible and avoid introducing followup bias, we have developed a multi-epoch observing strategy that is spread over several years. We present the evolution of the uncertainties in ephemeris position and orbital elements as the objects progress through the epochs. We then present a small 10-object sample that was tracked in this manner as part of a preliminary survey starting a year before the main CFEPS project. We describe the CFEPS survey simulator, to be released in 2006, which allows theoretical models of the Kuiper Belt to be compared with the survey discoveries since CFEPS has a well-documented pointing history with characterized detection efficiencies as a function of magnitude and rate of motion on the sky. Using the pre-survey objects we illustrate the usage of the simulator in modeling the classical Kuiper Belt.Comment: to be submitted to Icaru

Taller: Encerrados pero enREDados

La exclusión sociocultural de la vejez genera abandono, invisibilidad, nulidad de derechos y pocas oportunidades para que las personas mayores que habitan en el Área Metropolitana de Guadalajara vivan plenamente esta etapa de sus vidas. El objetivo fue empoderar a las personas mayores que habitan en el AMG, a través de talleres de autocuidado (salud física y mental) y del desarrollo de proyectos de diseño colaborativo que generen alternativas que contribuyan a mejorar sus condiciones de vida para que resignifiquen esta etapa de su vida. El trabajo colaborativo a través del taller Encerrados pero enREDados permitió por medio de talleres virtuales abonar a la calidad de vida de este grupo poblacional en el contexto por COVID-19 mediante el uso de las aplicaciones de whatsapp y zoom. Se presenta a lo largo de este documento las experiencias de aprendizaje por estudiantes y la contribución social que implica el trabajar con personas mayores a partir de un contexto que ha implicado la emergencia sanitaria derivada por la pandemia de COVID 19 que ha llevado el experimentar y continuar en aislamiento social. Aún en el contexto en el que se mantiene el confinamiento, a través de distintas estrategias de intervención que buscaron sumar al bienestar cotidiano de este grupo etario abordando las siguientes temáticas: 1) Resignificación de la vejez, 2) Nutrición para personas mayores, 3) Accesibilidad y seguridad en el espacio público y privado, 4) Red de apoyo para la productividad en la vejez, 5) Accesibilidad y seguridad en el espacio público y privado, 6) Regulación emocional, 7) Accesibilidad y seguridad en el espacio público, 7) Red de apoyo para la productividad en la vejez, 9) Accesibilidad y seguridad en el espacio público y privado y 10) Regulación emocional en las que han participado adultos mayores inmersos dentro Sistema DIF en distintos municipios: Guadalajara, Zapopan,Tlaquepaque y Tlajomulco.ITESO, A.C

Rotational fission of Trans-Neptunian Objects. The case of Haumea

We present several lines of evidence based on different kinds of observations to conclude that rotational fission has likely occurred for a fraction of the known Trans-Neptunian Objects (TNOs). It is also likely that a number of binary systems have formed from that process in the trans-neptunian belt. We show that Haumea is a potential example of an object that has suffered a rotational fission. Its current fast spin would be a slight evolution of a primordial fast spin, rather than the result of a catastrophic collision, because the percentage of objects rotating faster than 4 hours would not be small in a maxwellian distribution of spin rates that fits the current TNO rotation database. On the other hand, the specific total angular momentum of Haumea and its satellites falls close to that of the high size ratio asteroid binaries, which are thought to be the result of rotational fissions or mass shedding. We also present N-body simulations of rotational fissions applied to the case of Haumea, which show that this process is feasible, might have generated satellites, and might have even created a "family" of bodies orbitally associated to Haumea. The orbitally associated bodies may come from the direct ejection of fragments according to our simulations, or through the evolution of a proto-satellite formed during the fission event. Also, the disruption of an escaped fragment after the fission might create the orbitally related bodies. If any of those mechanisms are correct, other rotational fission families may be detectable in the trans-neptunian belt in the future, and perhaps even TNO pairs might be found (pairs of bodies sharing very similar orbital elements, but not bound together)

Consumo lácteo y su impacto en la salud ósea de población adulta en Colombia. Recomendaciones de la Asociación Colombiana de Osteoporosis y Metabolismo Mineral, basadas en la evidencia

El calcio es el mineral más abundante del cuerpo y está contenido, en su mayoría, en el esqueleto. La ingesta de este elemento depende de la edad y de la condición del individuo. En efecto, existe una alta deficiencia en el consumo de calcio en la dieta a nivel mundial y nacional, según los estudios recientes que motivaron a la Asociación Colombiana de Osteoporosis y Metabolismo Mineral (ACOMM) para la elaboración de este manuscrito. En el desarrollo de este texto, se contactaron especialistas de diferentes disciplinas, con interés académico en salud ósea y nutrición. Mediante la consulta de literatura científica, de bases de datos como Embase, Pubmed, Scielo y Google Académico, y con la asesoría de un epidemiólogo, se profundizó en las propiedades de los lácteos, las características de la leche y sus derivados, sus beneficios para la salud ósea (densidad ósea y prevención de fracturas) y el riesgo cardiovascular. Además, se registraron las recomendaciones del consumo lácteo para la población y se desmitificaron algunos conceptos que no tenían bases en la evidencia científica, los cuales han causado a una disminución en el consumo de calcio de la dieta, con un impacto negativo en la salud ósea

Obonuco Andina nueva variedad mejorada de arveja para la zona de economía campesina del sur de Nariño.

El artículo presenta todas las características de la variedad mejorada de arveja, se muestra el origen genético, el comportamiento agronómico, los atributos culinarios, las cualidades de mercadeo, la descripción varietal, el manejo agronómico como la preparación del suelo, la fertilización, el sistema, densidad y época de siembra y el manejo de malezas, plagas y enfermedades y las conclusiones.Obonuco Andina, variedad mejorada de arveja para el sistema de economía campesina de Nariñ