Multichromatic colour-magnitude diagrams of the globular cluster NGC 6366

We present multichromatic isochrone fits to the colour-magnitude data of the globular cluster NGC 6366, based on Hubble Space Telescope Advanced Camera for Surveys/Wide Field Channel and Southern Astrophysical Research photometric data. We corrected the photometric data for differential reddening and calculated the mean ridge line of the colour-magnitude diagrams. We compared the isochrones of Dartmouth Stellar Evolution Database and PAdova and TRieste Stellar Evolution Code both with microscopic diffusion starting on the main sequence. Bracketing all previous determinations of this cluster, we tested metallicities from [Fe/H]=-1.00 to [Fe/H]=-0.50, and ages from 9 to 13 Gyr. After determining the total to selective extinction ratio only from stars belonging to this cluster, R_V=3.06+/-0.14, we found the parameters for this cluster to be E(B-V)=0.69+/-0.02(int)+/-0.04(ext), (m-M)_V=15.02+/-0.07(int)+/-0.13(ext), Age=11+/-1.15 Gyr. Evolutionary models fail to reproduce the low-Teff sequence in multiband colour-magnitude diagrams, indicating that they still have an incomplete physics. We found that the Dartmouth Stellar Evolution Database isochrones better fit the subgiant branch and low main sequence than the PAdova and TRieste Stellar Evolution Code.Comment: 9 pages, 5 figure

Anomalous reaction-transport processes: the dynamics beyond the Mass Action Law

In this paper we reconsider the Mass Action Law (MAL) for the anomalous reversible reaction $A\rightleftarrows B$ with diffusion. We provide a mesoscopic description of this reaction when the transitions between two states $A$ and $B$ are governed by anomalous (heavy-tailed) waiting-time distributions. We derive the set of mesoscopic integro-differential equations for the mean densities of reacting and diffusing particles in both states. We show that the effective reaction rate memory kernels in these equations and the uniform asymptotic states depend on transport characteristics such as jumping rates. This is in contradiction with the classical picture of MAL. We find that transport can even induce an extinction of the particles such that the density of particles $A$ or $B$ tends asymptotically to zero. We verify analytical results by Monte Carlo simulations and show that the mesoscopic densities exhibit a transient growth before decay.Comment: 4 pages, 3 figure

Finding the Higgs Boson through Supersymmetry

The study of displaced vertices containing two b--jets may provide a double discovery at the Large Hadron Collider (LHC): we show how it may not only reveal evidence for supersymmetry, but also provide a way to uncover the Higgs boson necessary in the formulation of the electroweak theory in a large region of the parameter space. We quantify this explicitly using the simplest minimal supergravity model with bilinear breaking of R-parity, which accounts for the observed pattern of neutrino masses and mixings seen in neutrino oscillation experiments.Comment: 7 pages, 7 figures. Final version to appear at PRD. Discussion and results were enlarge

Probing Neutrino Oscillations in Supersymmetric Models at the Large Hadron Collider

The lightest supersymmetric particle may decay with branching ratios that correlate with neutrino oscillation parameters. In this case the CERN Large Hadron Collider (LHC) has the potential to probe the atmospheric neutrino mixing angle with sensitivity competitive to its low-energy determination by underground experiments. Under realistic detection assumptions, we identify the necessary conditions for the experiments at CERN's LHC to probe the simplest scenario for neutrino masses induced by minimal supergravity with bilinear R parity violation.Comment: 11 pages, 6 figures. To appear in Physical Review

Quantum critical scaling of the geometric tensors

Berry phases and the quantum-information theoretic notion of fidelity have been recently used to analyze quantum phase transitions from a geometrical perspective. In this paper we unify these two approaches showing that the underlying mechanism is the critical singular behavior of a complex tensor over the Hamiltonian parameter space. This is achieved by performing a scaling analysis of this quantum geometric tensor in the vicinity of the critical points. In this way most of the previous results are understood on general grounds and new ones are found. We show that criticality is not a sufficient condition to ensure superextensive divergence of the geometric tensor, and state the conditions under which this is possible. The validity of this analysis is further checked by exact diagonalization of the spin-1/2 XXZ Heisenberg chain.Comment: Typos correcte

Probing neutrino mass with multilepton production at the Tevatron in the simplest R-parity violation model

We analyze the production of multileptons in the simplest supergravity model with bilinear violation of R parity at the Fermilab Tevatron. Despite the small R-parity violating couplings needed to generate the neutrino masses indicated by current atmospheric neutrino data, the lightest supersymmetric particle is unstable and can decay inside the detector. This leads to a phenomenology quite distinct from that of the R-parity conserving scenario. We quantify by how much the supersymmetric multilepton signals differ from the R-parity conserving expectations, displaying our results in the $m_0 \otimes m_{1/2}$ plane. We show that the presence of bilinear R-parity violating interactions enhances the supersymmetric multilepton signals over most of the parameter space, specially at moderate and large $m_0$.Comment: 26 pages, 23 figures. Revised version with some results corrected and references added. Conclusions remain the sam

A Simulation Model to Evaluate Supplementation of Tropical Forage Diets for Dairy Cows

A dynamic model of digestion kinetics has been built to evaluate dairy cattle diets based on tropical feeds and to estimate the potential of tropical forages for milk production associated with available supplements. Results of simulation were very consistent showing that grazed elephant grass alone can supply nutrients for cow maintenance and yield of 7.10 kg milk/day. Nevertheless, to produce 25 kg/day on grazed elephant grass, a dairy cow would need to be supplemented with 5.85 kg/day of a mixture of cottonseed meal (50%) plus ground maize (50%), while on maize silage it would be necessary 4.15 kg of the same supplementation. On the other hand, for the same amount of milk, a cow fed a sugarcane/urea-based diet would need 5.87 kg of the above mixture. As far as feeding cost is concerned, to reach the potential production of 25 kg of milk/day, a cow would expend US$1.19 on grazed elephant grass-based diet, as compared to US$ 1.40 on sugarcane- and maize silage-based diets. The present model showed to be an useful tool for assessing, preexperimentally, the potential response to supplementation of dairy cows fed tropical forages

Deaths due to oral cancer in Chile in the period 2002-2012

Indexación: Scopus; Scielo.Background: Oral cancer is the 15th most common cause of cancer death in the world. In Chile, 1% of all cancer deaths are related to oral and pharyngeal cancer. Aim: To determine mortality rates for oral cancer in Chile and its regions between 2002-2012. Material and Methods: Deaths and their causes between the years 2002-2012 were obtained from the Chilean National Statistics Institute. Crude and adjusted rates by age and sex were calculated for the country and its regions. The denominator was Chilean population on June 30, 2012 and the WHO standard population. Results: In the period studied, 1,611 individuals with a mean age of 67.6 years (63% men) died because of oral cancer. The most common location of the tumor was the tongue in 27% of cases and the parotid gland in 16%. The adjusted mortality rate in Chile was 0.85/100,000 inhabitants (1.13 and 0.58 in men and women, respectively). The regions with the highest rates were Antofagasta (1.51), Aysén (1.22) and Magallanes (1.17). Deaths among men occurred at younger ages than women. Conclusions: Mortality rates due to oral cancer in Chile are lower than abroad. The highest rates observed in some regions may be influenced by environmental factors such as arsenic contamination in Antofagasta and the lack of specialists and specialized care centers in Aysén and Magallanes. © 2018, Sociedad Medica de Santiago. All rights reserved.https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0034-98872018000400487&lng=en&nrm=iso&tlng=e