Neutrino masses and mixing parameters in a left-right model with mirror fermions

In this work we consider a left-right model containing mirror fermions with gauge group SU(3)$_{C} \otimes SU(2)_{L} \otimes SU(2)_{R} \otimes U(1)_{Y^\prime}$. The model has several free parameters which here we have calculated by using the recent values for the squared-neutrino mass differences. Lower bound for the mirror vacuum expectation value helped us to obtain crude estimations for some of these parameters. Also we estimate the order of magnitude of the masses of the standard and mirror neutrinos.Comment: 13 pages, version submitted to European Physical Journal

Typological analysis of slidequakes emitted from landslides: experiments on expander body pile and Sobradinho landslide (Brasilia, Brazil)

Reactivation of a landslide is usually accompanied by microseismic signals emitted from the deforming soil mass. The reproduction of similar signals in a physical model test conducted under control conditions can allow researchers to explore and test such complicated signals to improve the prediction of full-scale failure. The present study investigates the similarity between the slidequakes (microseismicity) naturally emitted from an existing colluvial landslide (Sobradinho, Brazil) in response to rainfalls and the emissions generated by a pullout test of an expander body (EB) pile in tropical soil under controlled conditions. The microseismic signals emitted from both experimental sites (i.e. the landslide and the EB pile test) were recorded and compared. Data were acquired by mini-arrays of four short-period seismometers. For the signal nomenclature, a typological scheme was adopted, in which sonograms/spectral contents of the signals were used. As a result, short duration microseismic signals were observed during the pullout test. In contrast, at the Sobradinho landslide, the testing detected signals of different characteristics whose source mechanisms have remained ambiguous, mainly because of the short duration of the data campaigns. However, at the landslide, propagating events were observed that might be attributed to the energies generated by the river bedload during the heavy rains. The present study offers some insight into the pre-collapse dynamic behavior of unstable slopes in clayey formations.- National Council for Scientific and Technological Development (CNPq), Brazil. - Federal District Foundation (FAP-DF), Brazil. - Pool of Brazilian Equipment (PegBr), Rio de Janeiro

Using Genetic Diversity in Deep Root Systems of Perennial Forage Grasses and Rice to Capture Carbon in Tropical Soils

Agricultural soils have the potential not only to be sinks of carbon dioxide (CO2) but also to mitigate the emissions of this gas to the atmosphere, thus, alleviating global warming. Perennial tropical grasses and rice upland and lowland varieties exhibit a large untapped genetic diversity in their root systems (e.g., deep rooting ability, exudation rates and chemical composition) that, if unlocked, could contribute to increased food production in crop-livestock systems while enhancing soil organic carbon (SOC) in tropical regions. Naturebased solutions that improve crop adaptation and SOC storage in tropical soils could help to remove CO2 from the atmosphere and thereby benefit the global climate system. With the launch of Future Seeds, one of the world’s largest repositories of tropical crop varieties, the Bezos Earth Fund (BEF) granted a major project within the Program of Future of Food. The focus of this BEF funded project is to: (i) develop novel high-throughput phenotyping methods to evaluate genetic diversity of root systems of tropical grasses and rice; (ii) unravel the potential of root systems in crop-livestock systems to replenish soil organic carbon (SOC) in human-intervened areas in tropical soils; (iii) identify and target hotspots/agroecological niches for SOC storage in tropical soils; and (iv) build capacity in conducting research on root systems and SOC storage towards carbon farming in tropical regions. Implementation of land-based SOC storage practices/projects (through carbon markets) based on deep rooting ability of perennial tropical forage grasses and rice cultivars in crop-pasture rotational systems could significantly reduce net emissions from tropical soils

Monitoring of Sobradinho landslide (Brasilia, Brazil) and a prototype vertical slope by time-lapse interferometry

The application of geophysical monitoring technologies may offer an opportunity to understand the dynamic of slopes in response to factors triggering their instability. In this study, Ambient Noise Interferometry was used as a monitoring approach on a man-made reduced-scale vertical slope and on a natural-scale landslide in Sobradinho (Brazil), under the influence of mechanical stress and rainfall, respectively. For both experiments, we adopted similar data acquisition system and processing workflow. After preprocessing of ambient seismic noise, the time-lapse changes were determined in terms of relative velocity changes using the moving window cross spectral technique. For the vertical slope, terrestrial laser scanning was also performed to detect crack or fissure generation. The prototype experiment results showed a decreasing trend of relative velocity changes and reached a minimum value of -0.6% at the end of the experiment. No change was detected on the digital elevation model that was computed from terrestrial laser scanning images, due to the absence of centimeter scale superficial fissures. At natural scale (Sobradinho landslide), no significant variation in relative velocity changes was detected for the rainy and non-rainy days, mainly because of the inadequate change in the degree of saturation, which was found within a relatively short period of data acquisition.- The Brazilian Council for Scientific and Technological Development (CNPq), - Research of the Federal District Foundation (FAP-DF), - University of Brasilia - Pool of Brazilian Equipment (PegBr), Rio de Janeiro. - UNAM projects: PAPIIT (IN117217)

Highly active antiretroviral therapy discontinuation time is associated with therapeutic failure among human immunodeficiency virus (HIV)-infected immigrant adults: A cohort study from a Peruvian referral hospital during the Venezuelan exodus

Objective: To evaluate the association between Highly Active Antiretroviral Therapy (HAART) discontinuation time and therapeutic failure (TF) in Venezuelan immigrants with HIV that restart HAART. Methods: We carried out a retrospective cohort study in a large hospital in Peru. We included Venezuelan immigrants who restarted HAART and were followed over at least 6 months. The primary outcome was TF. Secondary outcomes were immunologic (IF), virologic (VF) and clinical (CF) failures. The exposure variable was HAART discontinuation, categorised as no discontinuation, less than 6 months, and 6 months or more. We applied generalised linear models Poisson family with robust standard errors to calculate crude (cRR) and adjusted (aRR) relative risks by statistical and epidemiological criteria. Results: We included 294 patients, 97.2% were males, and the median age was 32 years. Out of all the patients, 32.7% discontinued HAART for less than 6 months, 15.0% discontinued for more than 6 months and the remaining 52.3% did not discontinue. The cumulative incidence of TF was 27.9%, 24.5% in VF, 6.0% in IF and 6.0% in CF. Compared with non-discontinued HAART patients, the discontinuation for less than 6 months (aRR = 1.98 [95% CI: 1.27–3.09]) and from 6 months to more (aRR = 3.17 [95% CI: 2.02–4.95]) increased the risk of TF. Likewise, treatment discontinuation of up to 6 months (aRR = 2.32 [95% CI: 1.40–3.84]) and from 6 months to more (aRR = 3.93 [95% CI: 2.39–6.45]) increased the risk of VF. Conclusions: HAART discontinuation increases the probability of TF and VF in Venezuelan immigrants.Revisión por pare