Decoherence in an accelerated universe

In this paper we study the decoherence processes of the semiclassical branches of an accelerated universe due to their interaction with a scalar field with given mass. We use a third quantization formalism to analyze the decoherence between two branches of a parent universe caused by their interaction with the vaccum fluctuations of the space-time, and with other parent unverses in a multiverse scenario.Comment: 11 pages, 2 figure

Achievements of a Bilingual Policy: The Colombian Journey

The Colombian journey to become a country with an educational system that develops bilingual skills in students began in 1979. More recently, Colombia National Ministry of Education presented Colombia’s National Bilingualism Program 2004–2019, a policy that recognized for the first time that mastering English was a matter of advantages in competitiveness for the country. Two important goals were established under this policy for 2014. First, 40% of secondary graduates should achieve at least an intermediate level—B1or threshold or independent user following the Common European Framework of Reference for Languages (CEFRL). Second, 20% of Bachelor degree (under) graduates should achieve at least a vantage or upper intermediate—B2 level. A descriptive approach was applied to the data and it was found that the neither goal was met. The impact of the different programs implemented should be evaluated, so goals proposed for 2025 can be achieved

Gender differences in dual diagnoses associated with cannabis use: A review

Gender differences in psychiatric disorders and drug use are well known. Cannabis is the most widely used illegal drug among young people. In recent years, its use has been related to the development of psychiatric pathologies; however, few studies have incorporated the gender perspective as of yet. The present work analyses the literature to determine the existence of gender differences in the development of psychotic, depressive and anxious symptoms associated with cannabis use. First, we describe cannabis misuse and its consequences, paying special attention to adolescent subjects. Second, the main gender differences in psychiatric disorders, such as psychosis, depression, anxiety and cannabis use disorders, are enumerated. Subsequently, we discuss the studies that have evaluated gender differences in the association between cannabis use and the appearance of psychotic, depressive and anxious symptoms; moreover, we consider the possible explanations for the identified gender differences. In conclusion, the studies referred to in this review reveal the existence of gender differences in psychiatric symptoms associated with cannabis use, although the direction of such differences is not always clear. Future research is necessary to discern the causal relationship between cannabis use and the development of psychiatric symptoms, as well as the gender differences foun

Understanding the 8 micron vs. Pa-alpha relationship on sub-arcsecond scales in Luminous Infrared Galaxies

This work explores in detail the relation between the 8 micron and the Pa-alpha emissions for 122 HII regions identified in a sample of 10 low-z LIRGs with nearly constant metallicity (12 + log (O/H) ~ 8.8). We use Gemini/T-ReCS high-spatial resolution (<~ 0.4" ~ 120 pc for the average distance of 60 Mpc of our sample) mid-infrared imaging (at 8.7 micron or 10.3 micron) together with HST/NICMOS continuum and Pa-alpha images. The LIRG HII regions extend the L_8micron vs. L_Pa-alpha relation found for HII knots in the high-metallicity SINGS galaxies by about two orders of magnitude to higher luminosities. Since the metallicity of the LIRG sample is nearly constant, we can rule out this effect as a cause for the scatter seen in the relationship. In turn, it is attributed to two effects: age and PAH features. The L_8micron/L_Pa-alpha ratio, which varies by a factor of ten for the LIRG HII regions, is reproduced by a model with instantaneous star formation and ages ranging from ~ 4 to 7.5 Myr. The remaining dispersion around the model predictions for a given age is probably due to differential contributions of the PAH features (the 8.6 micron, in our case) to the 8 micron emission from galaxy to galaxy.Comment: 16 pages, 9 figures, accepted for publication in ApJ; paper with full-resolution figures can be found at: http://damir.iem.csic.es/extragalactic

A High Spatial Resolution Mid-Infrared Spectroscopic Study of the Nuclei and Star-Forming Regions in Luminous Infrared Galaxies

We present a high spatial (diffraction-limited) resolution (~0.3") mid-infrared (MIR) spectroscopic study of the nuclei and star-forming regions of 4 local luminous infrared galaxies (LIRGs) using T-ReCS on the Gemini South telescope. We investigate the spatial variations of the features seen in the N-band spectra of LIRGs on scales of ~100 pc, which allow us to separate the AGN emission from that of the star formation (SF). We compare our Gemini T-ReCS nuclear and integrated spectra of LIRGs with those obtained with Spitzer IRS. The 9.7um silicate absorption feature is weaker in the nuclei of the LIRGs than in the surrounding regions. This is probably due to the either clumpy or compact environment of the central AGN or young, nuclear starburst. We find that the [NeII] luminosity surface density is tightly and directly correlated with that of Pa-alpha for the LIRG star-forming regions (slope of 1.00+-0.02). Although the 11.3um PAH feature shows also a trend with Pa-alpha, this is not common for all the regions. We also find that the [NeII]\Pa-alpha ratio does not depend on the Pa-alpha equivalent width (EW), i.e., on the age of the ionizing stellar populations, suggesting that, on the scales probed here, the [NeII] emission line is a good tracer of the SF activity in LIRGs. On the other hand, the 11.3um PAH\Pa-alpha ratio increases for smaller values of the Pa-alpha EW (increasing ages), indicating that the 11.3um PAH feature can also be excited by older stars than those responsible for the Pa-alpha emission. Additional high spatial resolution observations are essential to investigate, in a statistical way, the star formation in local LIRGs at the smallest scales and to probe ultimately whether they share the same physical properties as high-z LIRGs, ULIRGs and submillimiter galaxies.Comment: 23 pages (apjstyle), 19 figures, accepted for publicacion in Ap

A common framework for the robust design of tuned mass damper techniques to mitigate pedestrian-induced vibrations in lively footbridges

The dynamic response of modern slender footbridges is usually sensitive to both the pedestrian actions and the uncertainties associated with their inherent structural behavior. Thus, tuned mass dampers have been widely integrated in the design of these structures to guarantee the fulfillment of the vibration serviceability limit state during their overall life cycle. Three different techniques of tuned mass dampers (active, semi-active and passive) are usually considered for this purpose. Although there are algorithms for the robust design of each particular technique, however, this specificity makes difficult the implementation of all these techniques in practical en gineering applications. Herein, the motion-based design method under uncertainty conditions is proposed and further implemented to create a common framework for the robust design of all these techniques when they are employed to mitigate pedestrian-induced vibrations in slender footbridges. According to this method, the design problem may be transformed into the combination of two sequential sub-problems: (i) a reliability multi objective optimization sub-problem; and (ii) a decision-making sub-problem. Subsequently, the performance of this proposal has been validated through a numerical case study in which the dynamic response of a steel footbridge has been controlled by three different tuned mass damper techniques designed according to the proposed common framework.Ministerio de Economía y Competitividad ( España) RTI2018-094945-B-C21Ministerio de Ciencia, Innovación y Universidades (España) RTI2018-099639-B-I0

Mass ingestion of gastroliths and other foreign bodies in three juvenile hooded seals (Cystophora cristata) stranded in north-western Iberian Peninsula

We present here three clinical cases involving mass ingestion of foreign bodies in Hooded seals (Cystophora cristata) stranded in north-western Iberian Peninsula. Although the presence of gastroliths is considered to be normal in pinnipeds, the cases presented here highlight how an excessive presence of them as well as other foreign bodies could result in rapid onset of a potentially lethal gastrointestinal stasis syndrome, which has to be quickly resolved, medically or surgically. Ultrasound examinations and posterior X-ray confirmation have demonstrated their utility to a rapid detection of gastric bodies, and have to be taken into account in Hooded seal routine clinical protocols. Finally, we conclude that it is particularly important to avoid the use of loose stones or sand over resting areas and to take extreme precautions with small items near the rehabilitation pools when dealing with this seal species.JM Alonso-Farré and M. Llarena-Reino are currently funded by Fundação para a Ciência e a Tecnologia, (Portugal), under post-doctoral fellowship SFRH/BPD/47251/2008, and pre-doctoral grant SFRH/BD/45398/2008, respectively.Peer reviewe

Understory plant communities show resistance to drought, hurricanes, and experimental warming in a wet tropical forest

Global climate change has led to rising temperatures and to more frequent and intense climatic events, such as storms and droughts. Changes in climate and disturbance regimes can have non-additive effects on plant communities and result in complicated legacies we have yet to understand. This is especially true for tropical forests, which play a significant role in regulating global climate. We used understory vegetation data from the Tropical Responses to Altered Climate Experiment (TRACE) in Puerto Rico to evaluate how plant communities responded to climate warming and disturbance. The TRACE understory vegetation was exposed to a severe drought (2015), 2 years of experimental warming (4°C above ambient in half of the plots, 2016–2017 and 2018–2019), and two major hurricanes (Irma and María, September 2017). Woody seedlings and saplings were censused yearly from 2015 to 2019, with an additional census in 2015 after the drought ended. We evaluated disturbance-driven changes in species richness, diversity, and composition across ontogeny. We then used Bayesian predictive trait modeling to assess how species responded to disturbance and how this might influence the functional structure of the plant community. Our results show decreased seedling richness after hurricane disturbance, as well as increased sapling richness and diversity after warming. We found a shift in species composition through time for both seedlings and saplings, yet the individual effects of each disturbance were not significant. At both ontogenetic stages, we observed about twice as many species responding to experimental warming as those responding to drought and hurricanes. Predicted changes in functional structure point to disturbance-driven functional shifts toward a mixture of fast-growing and drought-tolerant species. Our findings demonstrate that the tropical forest understory community is more resistant to climatic stressors than expected, especially at the sapling stage. However, early signs of changes in species composition suggest that, in a warming climate with frequent droughts and hurricanes, plant communities might shift over time toward fast-growing or drought-tolerant species