A predictive inline model for nonlinear stimulated Raman scattering in a hohlraum plasma

In this Letter, we introduce a new inline model for stimulated Raman scattering (SRS), which runs on our radiation hydrodynamics code TROLL. The modeling follows from a simplified version of a rigorous theory for SRS, which we describe, and accounts for nonlinear kinetic effects. It also accounts for the SRS feedback on the plasma hydrodynamics. We dubbed it PIEM because it is a fully PredIctivE Model, no free parameter is to be adjusted \textit{a posteriori}~in order to match experimental results. PIEM predictions are compared against experimental measurements performed at the Ligne d'Int\'egration Laser. From these comparisons, we discuss PIEM ability to correctly catch the impact of nonlinear kinetic effects on SRS

Developement of real time diagnostics and feedback algorithms for JET in view of the next step

Real time control of many plasma parameters will be an essential aspect in the development of reliable high performance operation of Next Step Tokamaks. The main prerequisites for any feedback scheme are the precise real-time determination of the quantities to be controlled, requiring top quality and highly reliable diagnostics, and the availability of robust control algorithms. A new set of real time diagnostics was recently implemented on JET to prove the feasibility of determining, with high accuracy and time resolution, the most important plasma quantities. With regard to feedback algorithms, new model–based controllers were developed to allow a more robust control of several plasma parameters. Both diagnostics and algorithms were successfully used in several experiments, ranging from H-mode plasmas to configuration with ITBs. Since elaboration of computationally heavy measurements is often required, significant attention was devoted to non-algorithmic methods like Digital or Cellular Neural/Nonlinear Networks. The real time hardware and software adopted architectures are also described with particular attention to their relevance to ITER.Comment: 12th International Congress on Plasma Physics, 25-29 October 2004, Nice (France

Effect of the Dielectric-Constant Mismatch and Magnetic Field on the Binding Energy of Hydrogenic Impurities in a Spherical Quantum Dot

Within the effective mass approximation and variational method the effect of dielectric constant mismatch between the size-quantized semiconductor sphere, coating and surrounding environment on impurity binding energy in both the absence and presence of a magnetic field is considered. The dependences of the binding energy of a hydrogenic on-center impurity on the sphere and coating radii, alloy concentration, dielectric-constant mismatch, and magnetic field intensity are found for the GaAs-Ga_(1-x)Al_(x)As-AlAs (or vacuum) system

Electron transport and energy relaxation in dilute magnetic alloys

We consider the effect of the RKKY interaction between magnetic impurities on the electron relaxation rates in a normal metal. The interplay between the RKKY interaction and the Kondo effect may result in a non-monotonic temperature dependence of the electron momentum relaxation rate, which determines the Drude conductivity. The electron phase relaxation rate, which determines the magnitude of the weak localization correction to the resistivity, is also a non-monotonic function of temperature. For this function, we find the dependence of the position of its maximum on the concentration of magnetic impurities. We also relate the electron energy relaxation rate to the excitation spectrum of the system of magnetic impurities. The energy relaxation determines the distribution function for the out-of-equilibrium electrons. Measurement of the electron distribution function thus may provide information about the excitations in the spin glass phase.Comment: 15 pages, 5 figure

Dietary transition in native populations of Northern Tierra del Fuego during the Salesian missionary period: an isotopic approach

La misión salesiana La Candelaria funcionó de 1893 a 1928 en el norte de Tierra del Fuego, aunque su cementerio fue usado hasta 1948. Las fuentes históricas sugieren que los nativos que la habitaron sufrieron fuertes cambios en su dieta con respecto a los cazadoresrecolectores de la zona. El cambio estaría caracterizado por un gran incremento en el consumo de harina, arroz, papas y azúcar, que remplazan al guanaco como fuente principal de alimento. Nuestro objetivo es evaluar la transición alimentaria de los habitantes de la misión a través del análisis de isótopos estables de carbono y nitrógeno sobre huesos (colágeno, apatita) y dientes (dentina, esmalte) de 23 individuos exhumados del cementerio. Los valores de δ15N en colágeno (δ15Nc) y de δ13C tanto en colágeno (δ13Cc) como en apatita (δ13Ca) de individuos del cementerio resultaron más bajos que los valores publicados para la región para períodos pre-contacto. Dentro del cementerio, los valores de δ15Nc y de δ13Ca resultaron más bajos que los de δ15Nd (dentina) y de δ13Ce (esmalte), pero no hubo diferencias entre valores de δ13Cc y δ13Cd. Los valores de δ15Nd y δ13Cd resultaron significativamente más bajos que los valores de colágeno para períodos pre-contacto. Estos resultados son consistentes con la hipótesis planteada por las fuentes históricas y sugieren un desequilibrio en la dieta, con una mayor proporción de carbohidratos y una menor proporción de proteínas animales en los habitantes de la misión con relación a los cazadores-recolectores de Tierra del Fuego de períodos pre-contacto.The Salesian mission La Candelaria was run from 1893 to 1928 in the north of Tierra del Fuego, but its cemetery was in use until 1948. Historical sources suggest that the natives living there underwent marked dietary changes with respect to the hunter-gatherers of the area. The change can be characterized by a large increase in the consumption of flour, rice, potatoes, and sugar, in replacement of guanaco, as their main food source. Our objective is to evaluate the dietary transition experienced by the inhabitants of the mission through the analysis of stable isotopes of carbon and nitrogen on bones (collagen, apatite) and teeth (dentin, enamel) of 23 individuals exhumed from the cemetery. The δ15N values in collagen (δ15Nc), and δ13C values both in collagen (δ13Cc) and in apatite (δ13Ca) of samples from the cemetery were lower than the values published for the region in pre-contact periods. Within the cemetery, the δ15Nc, δ13Cc and δ13Ca values were lower than those of δ15Nd (dentin) and δ13Ce (enamel), but there were no differences between δ13Cc and δ13Cd values. The δ15Nd and δ13Cd values were significantly lower than the isotope values of collagen for pre-contact periods. The results are consistent with the hypothesis raised by historical sources and suggest an imbalance in the diet, with a higher proportion of carbohydrates and a lower proportion of animal proteins in the inhabitants of the mission in comparison with the hunter-gatherers of Tierra del Fuego of pre-contact periods.Asociación de Antropología Biológica de la República Argentin

Anomalous asymmetry of magnetoresistance in NbSe3_3 single crystals

A pronounced asymmetry of magnetoresistance with respect to the magnetic field direction is observed for NbSe$_3$ crystals placed in a magnetic field perpendicular to their conducting planes. It is shown that the effect persists in a wide temperature range and manifests itself starting from a certain magnetic induction value $B_0$, which at $T=4.2$ K corresponds to the transition to the quantum limit, i.to the state where the Landay level splitting exceeds the temperature.Comment: 4 pages, 6 figures, to be appeared in JETP Let

Dietary transition in native populations of Northern Tierra del Fuego during the Salesian missionary period: an isotopic approach

La misión salesiana La Candelaria funcionó de 1893 a 1928 en el norte de Tierra del Fuego, aunque su cementerio fue usado hasta 1948. Las fuentes históricas sugieren que los nativos que la habitaron sufrieron fuertes cambios en su dieta con respecto a los cazadoresrecolectores de la zona. El cambio estaría caracterizado por un gran incremento en el consumo de harina, arroz, papas y azúcar, que remplazan al guanaco como fuente principal de alimento. Nuestro objetivo es evaluar la transición alimentaria de los habitantes de la misión a través del análisis de isótopos estables de carbono y nitrógeno sobre huesos (colágeno, apatita) y dientes (dentina, esmalte) de 23 individuos exhumados del cementerio. Los valores de δ15N en colágeno (δ15Nc) y de δ13C tanto en colágeno (δ13Cc) como en apatita (δ13Ca) de individuos del cementerio resultaron más bajos que los valores publicados para la región para períodos pre-contacto. Dentro del cementerio, los valores de δ15Nc y de δ13Ca resultaron más bajos que los de δ15Nd (dentina) y de δ13Ce (esmalte), pero no hubo diferencias entre valores de δ13Cc y δ13Cd. Los valores de δ15Nd y δ13Cd resultaron significativamente más bajos que los valores de colágeno para períodos pre-contacto. Estos resultados son consistentes con la hipótesis planteada por las fuentes históricas y sugieren un desequilibrio en la dieta, con una mayor proporción de carbohidratos y una menor proporción de proteínas animales en los habitantes de la misión con relación a los cazadores-recolectores de Tierra del Fuego de períodos pre-contacto.The Salesian mission La Candelaria was run from 1893 to 1928 in the north of Tierra del Fuego, but its cemetery was in use until 1948. Historical sources suggest that the natives living there underwent marked dietary changes with respect to the hunter-gatherers of the area. The change can be characterized by a large increase in the consumption of flour, rice, potatoes, and sugar, in replacement of guanaco, as their main food source. Our objective is to evaluate the dietary transition experienced by the inhabitants of the mission through the analysis of stable isotopes of carbon and nitrogen on bones (collagen, apatite) and teeth (dentin, enamel) of 23 individuals exhumed from the cemetery. The δ15N values in collagen (δ15Nc), and δ13C values both in collagen (δ13Cc) and in apatite (δ13Ca) of samples from the cemetery were lower than the values published for the region in pre-contact periods. Within the cemetery, the δ15Nc, δ13Cc and δ13Ca values were lower than those of δ15Nd (dentin) and δ13Ce (enamel), but there were no differences between δ13Cc and δ13Cd values. The δ15Nd and δ13Cd values were significantly lower than the isotope values of collagen for pre-contact periods. The results are consistent with the hypothesis raised by historical sources and suggest an imbalance in the diet, with a higher proportion of carbohydrates and a lower proportion of animal proteins in the inhabitants of the mission in comparison with the hunter-gatherers of Tierra del Fuego of pre-contact periods.Asociación de Antropología Biológica de la República Argentin

Assessing the Behavioural Responses of Small Cetaceans to Unmanned Aerial Vehicles

Unmanned Aerial Vehicles (UAVs), or drones, have recently emerged as a relatively affordable and accessible method for studying wildlife. Vertical Take-off and Landing (VTOL) UAVs are appropriate for morphometric, behavioural, abundance and demographic studies of marine mammals, providing a stable, nonintrusive and highly manoeuvrable platform. Previous studies using VTOL UAVs have been conducted on various marine mammal species, but specific studies regarding behavioural responses to these devices are limited and scarce. The aim of this study was to evaluate the immediate behavioural responses of common (Delphinus delphis) and bottlenose (Tursiops truncatus) dolphins to a VTOL UAV flown at different altitudes. A multirotor (quadcopter) UAV with an attached GoPro camera was used. Once a dolphin group was located, the UAV was flown at a starting height of 50 m directly above the group, subsequently descending 5 m every 30 s until reaching 5 m. We assessed three behavioural responses to a VTOL UAV at different heights: (i) direction changes, (ii) swimming speed and (iii) diving. Responses by D. delphis (n = 15) and T. truncatus (n = 10) groups were analysed separately. There were no significant responses of T. truncatus to any of the studied variables. For D. delphis, however, there were statistically significant changes in direction when the UAV was flown at a height of 5 m. Our results indicate that UAVs do not induce immediate behavioural responses in common or bottlenose dolphins when flown at heights > 5 m, demonstrating that the use of VTOL UAVs to study dolphins has minimal impact on the animals. However, we advise the use of the precautionary principle when interpreting these results as characteristics of this study site (e.g., high whale-watching activity) may have habituated dolphins to anthropogenic disturbance.The authors would like to thank all AIMM volunteers who participated in the data collection and particularly to the research assistants Selma Bajraktarevic, Laura van Zonneveld, Henry Harper and Alicia Quirin. This work was conducted under the authorisation of the Portuguese Conservation Institute (ICNF: AOC/17/2016).Ye

Oceanographic Determinants of the Abundance of Common Dolphins (Delphinus delphis) in the South of Portugal.

Off mainland Portugal, the common dolphin (Delphinus delphis) is the most sighted cetacean, although information on this species is limited. The Atlantic coast of Southern Portugal is characterized by an intense wind-driven upwelling, creating ideal conditions for common dolphins. Using data collected aboard whale-watching boats (1929 sightings and 4548 h effort during 2010–2014), this study aims to understand the relationships between abundance rates (AR) of dolphins of different age classes (adults, juveniles, calves and newborns) and oceanographic [chlorophyll a (Chl-a) and sea surface temperature (SST)] variables. Over 70% of the groups contained immature animals. The AR of adults was negatively related with Chl-a, but not related to SST values. The AR of juveniles was positively related with SST. For calves and newborns, although the relationship between SST and AR is similar to that observed for juveniles, the effect could not be distinguished from zero. There was no relationship between Chl-a levels and the AR of juveniles, calves and newborns. These results corroborate previous findings that common dolphins tend to occur in highly productive areas demonstrating linkages between their abundance and oceanographic variables, and that this region may be a potential nursery ground.This research was funded by Associação para a Investigação do Meio Marinho (AIMM) and Fundação para a Ciência e a Tecnologia (FCT), through Programa Investigador FCT 2013 granted to RR. FCT also supported this study through (i) the strategic project UID/MAR/04292/2019 granted to MARE and (ii) PhD grant to J.C. (SFRH/BD/134156/2017), M.I.L. (SFRH/BD/84297/2012) and F.O.B. (SFRH/BD/147294/2019).Ye