On the collapse in fourth order gravities

The gravitational collapse in fourth order theories of gravity defined by an arbitrary action of the scalar curvature shows significant deviations with General Relativity. The presence of a new scalar mode produces a higher initial contraction that favors the reduction of the collapsing time. However, depending on the particular model, there are fundamental differences when the modifications to the General Relativity collapse leave the linear regime. These analyses can be used to exclude an important region of the parameter space associated with alternative gravitational models.Comment: 4 pages, 2 figures, Contribution to the Proceedings of Spanish Relativity Meeting ERE2011, Madrid 201

Rare top decay t-> c l+l- as a probe of new physics

The rare top decay t-> c l+l-, which involves flavor violation, is studied as a possible probe of new physics. This decay is analyzed with the simplest Standard Model extensions with additional gauge symmetry formalism. The considered extension is the Left-Right Symmetric Model, including a new neutral gauge boson Z' that allows to obtain the decay at tree level through Flavor Changing Neutral Currents (FCNC) couplings. The neutral gauge boson couplings are considered diagonal but family non-universal in order to induce these FCNC. We find the $BR(t-> c l+l-)~10^{-13} for a range 1 TeV < M_{Z'} < 3 TeV.Comment: 9 pages, 6 figure

Efecto de seis dietas en el crecimiento y supervivencia de poslarvas de abulón rojo (Haliotis rufescens) y su híbrido (H. rufescens ♀ × H. fulgens ♂)

One of the main bottlenecks in abalone aquaculture is maintaining individuals during the weaning stage, when the natural diet changes from diatoms (postlarvae) to macroalgae (juvenile). During this period, abalone pass through profound morphological and physiological changes, which suitable nutrient requirements must sustain. An inadequate diet can result in adverse effects such as late metamorphosis, starvation, slow growth and even death during this phase. Two strategies have been proposed to increase the growth and survival rates of weaning abalone: (i) extending feeding with benthic diatoms and (ii) abalone hybridization via interspecific crosses. To evaluate the efficiency of the two strategies, we assessed the growth and survival rates of postlarvae of pure red abalone (Haliotis rufescens) and a hybrid obtained by crossing red abalone females with green abalone (H. fulgens) males. Both crosses were supplied with six different diets consisting of either one macroalgae mono-diet (Macrocystis pyrifera or Ulva ohnoi) or a mixture with Navicula incerta. Overall, cross-specific diets achieved better growth rates, suggesting that each cross may need specific food items (nutrients) during weaning. Moreover, pure red abalone generally showed the highest growth rates, while the hybrid abalone showed the highest survival rates with most tested diets. Hence, hybrids appear to be better at withstanding stressful conditions, and their use in aquaculture could reduce losses and increase commercial production.&nbsp; &nbsp;Uno de los principales cuellos de botella en la acuicultura de abulón es el mantenimiento de los individuos durante la fase de destete, cuando la dieta natural cambia de diatomeas (postlarvas) a macroalgas (juveniles). Durante este período, el abulón pasa por profundos cambios morfológicos y fisiológicos, que deben ser sostenidos por una alimentación adecuada. Una dieta inadecuada puede provocar efectos adversos como: metamorfosis tardía, inanición, crecimiento lento e incluso la muerte durante esta fase. Por ello, se han propuesto dos estrategias para aumentar las tasas de crecimiento y supervivencia del abulón durante la fase de destete: (i) ampliar el período de alimentación con diatomeas bentónicas y (ii) la hibridación de abulones mediante cruces interespecíficos. Para determinar la eficacia de ambas estrategias, se evaluaron las tasas de crecimiento y supervivencia de postlarvas de abulón rojo puro (Haliotis rufescens) y de un híbrido obtenido mediante el cruce de hembras de abulón rojo y machos de abulón azul (H. fulgens). A ambos cruces se les suministraron seis dietas diferentes consistentes en una mono dieta de macroalgas (Macrocystis pyrifera, Ulva ohnoi) o en una mezcla con Navicula incerta. En general, con las dietas específicas para cada cruce se obtuvieron mejores tasas de crecimiento, lo que sugiere que cada cruce requiere alimentos (nutrientes) específicos durante el destete. Además, el abulón rojo puro mostró en general las tasas de crecimiento más altas, mientras que en el abulón híbrido se obtuvieron las mayores tasas de supervivencia con la mayoría de las dietas probadas. Por lo que los híbridos parecen soportar mejor las condiciones de estrés, y su uso en la acuicultura podría ayudar a reducir las pérdidas y aumentar su producción comercial

The magnetically-active, low-mass, triple system WDS 19312+3607

Aims: We investigated in detail the system WDS 19312+3607, whose primary is an active M4.5Ve star previously thought to be young (tau ~ 300-500 Ma) based on high X-ray luminosity. Methods: We collected intermediate- and low-resolution optical spectra taken with 2 m-class telescopes, photometric data from the $B$ to 8 mum bands, and eleven astrometric epochs with a time baseline of over 56 years for the two components in the system, G 125-15 and G 125-14. Results: We derived M4.5V spectral types for both stars, confirmed their common proper motion, estimated the heliocentric distance and projected physical separation, determined the galactocentric space velocities, and deduced a most-probable age older than 600 Ma. We discovered that the primary, G 125-15, is in turn an inflated, double-lined, spectroscopic binary with a short period of photometric variability of P ~ 1.6 d, which we associated to orbital synchronisation. The observed X-ray and Halpha emissions, photometric variability, and abnormal radius and effective temperature of G 125-15 AB indicate strong magnetic activity, possibly due to fast rotation. Besides, the estimated projected physical separation between G 125-15 AB and G 125-14 of about 1200 AU makes WDS 19312+3607 to be one of the widest systems with intermediate M-type primaries. Conclusions: G 125-15 AB is a nearby (d ~ 26 pc), bright (J ~ 9.6 mag), active spectroscopic binary with a single proper-motion companion of the same spectral type at a wide separation. They are thus ideal targets for specific follow-ups to investigate wide and close multiplicity or stellar expansion and surface cooling due to reduced convective efficiency.Comment: A&A, in pres

Agriculture 4.0: Is Mexico Ready?

Objective: To analyze the possibilities and actions required to foster the introduction of technologies consistent with the term “agriculture 4.0” in Mexico.Design/Methodology/Approach: To identify providers of technology in Mexico. To present the cost-benefit equation regarding the adoption of said technology as applied to the cultivation of maize in different regions. Todesign and construct an adoption propensity index that will serve as a basis to propose focused and adequate actions to remove technology access barriers.Results: Mexico has a young and wide offer of technology, both tangible and intangible, where digital platforms of agricultural management, mobile apps, and remote monitoring predominate. The cost-benefit relationshipoffers a large margin to adopt new technologies. However, there are adoption barriers (related to education or infrastructure, for instance) that represent a challenge to different regions of the country: the northern,northeastern, and western states of Mexico are more likely to adopt new technologies.Study limitations/Implications: Further experimental and field analysesare required to delve deeper into potential additional barriers (culture-related, for example). Agro productividad 2022. https://doi.org/10.32854/xxxxxx (Los autores no deben realizar ningún cambio en este apartado) 2 of 8 Findings/Conclusions: The cost-benefit analysis offers a large margin foradoption. However, the propensity to adopt is associated to restrictingfactors such as the producers’ educational level, the production unit’s sizeand level of mechanization, the access to and use of Information andCommunication Technologies, and the telecoms infrastructure, whosegeographic disparity is significant. The public sector’s intervention isdesirable to reduce the gap between the supply and demand oftechnologies, as well as the access barriers to the latter

Development Environment Using FPGA for Domotics Applications Based on X10 Technology

This communication proposes a basic software and hardware architecture of a controller for the X10 technology interface CM11A, oriented to the world of home automation. The implementation of the system is based in the use of programmable devices such as FPGA (Field Programmable Gate Array). With this controller an end user will be able to control and to manage a set of devices distributed in a domotics space.Ministerio de Educación y Ciencia TEC2005- 04359/MICMinisterio de Educación y Ciencia TSI2006-13390-C02-02Junta de Andalucía TIC2006-635Junta de Andalucía TIC214

Environmental Epigenetic Changes, as Risk Factors for the Development of Diseases in Children: A Systematic Review

Background: Children are susceptible to environmental contaminants and are at risk of developing diseases, more so if the exposure begins at an early age. Epidemiological studies have postulated the hypothesis of the fetal origin of disease, which is mediated by epigenetic changes. Epigenetic marks are inheritable; they modulate the gene expression and can affect human health due to the presence of environmental factors. Objective: This review focuses on DNA-methylation and its association with environmental-related diseases in children. Methods: A search for studies related to DNA-methylation in children by pre- or post-natal environmental exposures was conducted, and those studies with appropriate designs and statistical analyses and evaluations of the exposure were selected. Findings: Prenatal and early life environmental factors, from diet to exposure to pollutants, have been associated with epigenetic changes, specifically DNA-methylation. Thus, maternal nutrition and smoking and exposure to air particulate matter, polycyclic aromatic hydrocarbons, arsenic, heavy metals, persistent organic pollutants, and some endocrine disrupters during pregnancy have been associated with genomic and gene-specific newborns’ DNA-methylation changes that have shown in some cases sex-specific patterns. In addition, these maternal factors may deregulate the placental DNA-methylation balance and could induce a fetal reprogramming and later-in-life diseases. Conclusions: Exposure to environmental pollutants during prenatal and early life can trigger epigenetic imbalances and eventually the development of diseases in children. The integration of epigenetic data should be considered in future risk assessments