On the nonlinear stability of mKdV breathers

A mathematical proof for the stability of mKdV breathers is announced. This proof involves the existence of a nonlinear equation satisfied by all breather profiles, and a new Lyapunov functional which controls the dynamics of small perturbations and instability modes. In order to construct such a functional, we work in a subspace of the energy one. However, our proof introduces new ideas in order to attack the corresponding stability problem in the energy space. Some remarks about the sine-Gordon case are also considered.Comment: 7 p

Hurwitz theorem and parallelizable spheres from tensor analysis

By using tensor analysis, we find a connection between normed algebras and the parallelizability of the spheres S$^1$, S$^3$ and S$^7.$ In this process, we discovered the analogue of Hurwitz theorem for curved spaces and a geometrical unified formalism for the metric and the torsion. In order to achieve these goals we first develope a proof of Hurwitz theorem based in tensor analysis. It turns out that in contrast to the doubling procedure and Clifford algebra mechanism, our proof is entirely based in tensor algebra applied to the normed algebra condition. From the tersor analysis point of view our proof is straightforward and short. We also discuss a possible connection between our formalism and the Cayley-Dickson algebras and Hopf maps.Comment: slightly changed conten

Arsenic levels in bovine tissues in the southeast of the province Córdoba, Argentina

El arsénico es un contaminante natural de aguas subterráneas en una amplia zona de Argentina, en particular el sudeste de la provincia de Córdoba es una de las regiones más afectadas. La información a nivel mundial acerca de la transferencia de arsénico a la cadena agroalimentaria particularmente a productos cárnicos es escasa. En este trabajo, se determinaron las concentraciones de arsénico en riñón, hígado, músculo esquelético y glándula mamaria en bovinos de la zona de estudio. Los órganos donde se registraron las mayores concentraciones de arsénico fueron hígado y riñón. Los niveles hallados en hígado estuvieron entre 27,0 y 46,5 ng/g y en riñón, entre 24,0 y 73,2 ng/g. En las muestras de músculo y glándula mamaria, las concentraciones estuvieron en todos los casos por debajo del límite de detección de la técnica utilizada. Las concentraciones de arsénico en los diferentes tejidos analizados se encontraron dentro de los límites recomendados a nivel nacional.Arsenic is a groundwater contaminant widely distributed in Argentina. One of the most affected area is the southeast of Cordoba province. The information about the transfer of arsenic to the food chain and meat products is scarce. In this study, the concentrations of arsenic in kidney, liver, muscle and udder in cattle in the study area were analyzed. The highest concentrations of arsenic were found in liver and kidney. The levels found in liver ranged from 27.0 to 46.5 ng/g while in kidney, ranged between 24.0 to 73.2 ng /g. In muscle and udder samples arsenic were below the detection limit of the technique in all cases. The levels of arsenic in the analyzed tissues were within the national recommended limits.Fil: Pérez Carrera, Alejo Leopoldo. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias. Centro de Estudios Transdisciplinarios del Agua; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Pérez Gardiner, M. L.. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias. Centro de Estudios Transdisciplinarios del Agua; ArgentinaFil: Fernandez Cirelli, Alicia. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias. Centro de Estudios Transdisciplinarios del Agua; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Climate fluctuations during the Holocene in NW Iberia: high and low latitude linkages

International audienceHigh resolution benthic foraminiferal oxygen and carbon stable isotopes (?18O, ?13C) from core EUGC-3B are used here to infer rapid climatic changes for the last 8500 yr in the Ría de Muros (NW Iberian Margin). Benthic foraminiferal ?18O and ?13C potentially register migrations in the position of the hydrographic front formed between two different intermediate water masses: Eastern North Atlantic Central Water of subpolar origin (ENACWsp), and subtropical origin (ENACWsp). The isotopic records have been compared with two well established North Atlantic marine Holocene paleoceanographic records from low (Sea Surface Temperatures anomalies off Cape Blanc, NW Africa) and high latitudes (Hematite Stained Grains percentage, subpolar North Atlantic). This comparison clearly demonstrates that there is a strong link between high- and low-latitude climatic perturbations at centennial-millennial time scales during the Holocene. Spectral analyses also points at a pole-to-equator propagation of the so-called 1500 yr cycles. Our results demonstrate that during the Holocene, the NW Iberian Margin has undergone a series of cold episodes which are likely triggered at high latitudes in the North Atlantic and are rapidly propagated towards lower latitudes. Conceivably, the propagation of these rapid climatic changes involves a shift of atmospheric and oceanic circulatory systems and so a migration of the hydrographical fronts and water masses all along the North Atlantic area

Ultrathin carbon nanotube with single, double, and triple bonds

A metastable carbon nanotube with single, double, and triple bonds has been predicted from abinitio simulation. It results from the relaxation of an ideal carbon nanotube with chirality (2,1), without any potential barrier between the ideal nanotube and the new structure. Ten-membered carbon rings are formed by breaking carbon bonds between adjacent hexagons; eight-membered rings, already present in the ideal structure, become the smallest rings. This structure is stable in molecular dynamics simulations at temperatures up to 1000K. Raman, infrared, and optical absorption spectra are simulated to allow its identification in the laboratory. The structure can be described as a double helical chain with alternating single, double, and triple bonds, where the chains are bridged by single bondsThis work was supported by Grants No. SB2010-0119 (MEC), No. CTQ2010-19232 (MICIN), and No. A1/035856/11 (AECID

Reproductive biology of male franciscanas (Pontoporia blainvillei) (Mammalia: Cetacea) from Rio Grande do Sul, southern Brazil

The reproductive biology of male franciscanas (Pontoporia blainvillei), based on 121 individuals collected in Rio Grande do Sul State, southern Brazil, was studied. Estimates on age, length, and weight at attainment of sexual maturity are presented. Data on the reproductive seasonality and on the relationship between some testicular characteristics and age, size, and maturity status are provided. Sexual maturity was assessed by histological examination of the testes. Seasonality was determined by changes in relative and total testis weight, and in seminiferous tubule diameters. Testis weight, testicular index of maturity, and seminiferous tubule diameters were reliable indicators of sexual maturity, whereas testis length, age, length, and weight of the dolphin were not. Sexual maturity was estimated to be attained at 3.6 years (CI 95% =2.7–4.5) with the DeMaster method and 3.0 years with the logistic equation. Length and weight at attainment of sexual maturity were 128.2 cm (CI 95%=125.3–131.1 cm) and 26.4 kg (CI 95% =24.7–28.1 kg), respectively. It could not be verified that there was any seasonal change in the testis weight and in the seminiferous tubule diameters in mature males. It is suggested that at least some mature males may remain reproductively active throughout the year. The extremely low relative testis weight indicates that sperm competition does not occur in the species. On the other hand, the absence of secondary sexual characteristics, the reversed sexual size dimorphism, and the small number of scars from intrassexual combats in males reinforce the hypothesis that male combats for female reproductive access may be rare for franciscana. It is hypothesized that P. blainvillei form temporary pairs (one male copulating with only one female) during the reproductive period

Techno-economic demand projections and scenarios for the Bolivian energy system

Increasing energy access in emerging economies has played an important role to maintain or achieve desirable social and economic development targets. As a consequence, the growing energy requirements need policy instruments to ensure energy supply for future generations. The literature reports many studies with different approaches to model and test policy measures in the energy sector, however few energy-related studies for Bolivia are available. This paper addresses this knowledge gap, representing the first national level energy demand model and projections for Bolivia. The model use demographic, economic, technology and policy trends with a pragmatic model structure that combines bottom-up and top-down modelling. The scenario analysis has a particular focus on alternatives for energy savings, energy mix diversification and air quality. Three scenarios were analysed: Energy Savings, Fuel Substitution and the aggregate effects in a Combined scenario. The reference scenario results show the overall energy consumption grows 134% in 2035 compared to 2012 with an annual average growth of 3.8%. The final energy demand in the energy savings scenario is 8.5% lower than the Reference scenario, 1.5% lower in the fuel substitution scenario and 9.4% lower in the combined Scenario. The aggregate impact of both energy savings and fuel substitution measures leads to potential avoided emissions of 25.84 million Tons of CO2 equivalent in the model horizon 2012-2035

SP-0489: HPV-transformation in the cervix and at non-cervical sites

Pla general d'un dels panells horitzontals sobre espais verds de Barcelona a l'exposició Ciutat. Barcelona projecta a l'Edifici Fòrum. Exposició sobre la planificació urbanística i arquitectònica de Barcelon

Selective Deuterium Ion Acceleration Using the Vulcan PW Laser

We report on the successful demonstration of selective acceleration of deuterium ions by target-normal sheath acceleration (TNSA) with a high-energy petawatt laser. TNSA typically produces a multi-species ion beam that originates from the intrinsic hydrocarbon and water vapor contaminants on the target surface. Using the method first developed by Morrison, et al.,$^{1}$ an ion beam with $>$99$\%$ deuterium ions and peak energy 14 MeV/nucleon is produced with a 200 J, 700 fs, $>10^{20} W/cm^{2}$ laser pulse by cryogenically freezing heavy water (D$_{2}$O) vapor onto the rear surface of the target prior to the shot. Within the range of our detectors (0-8.5$^{\circ}$), we find laser-to-deuterium-ion energy conversion efficiency of 4.3$\%$ above 0.7 MeV/nucleon while a conservative estimate of the total beam gives a conversion efficiency of 9.4$\%$.Comment: 5 pages, 5 figure