Multiple thermoclines are barriers to vertical exchange in the subarctic Pacific during SUPER, May 1984

As part of the Subarctic Pacific Ecosystem Research program, we made observations of upper ocean physical and biological properties at 50N; 145W during 12–21 May 1984 from a drifting buoy, instrumented with a thermistor chain and meteorological sensors; a CTD/rosette bottle profiler; a shipboard solar radiometer; and a microstructure profiler equipped with a fast response thermistor and two airfoil velocity probes. At that time, the ocean above the seasonal thermocline was divided by a shallow thermocline step (∼0.5°C) into two layers with different turbulence characteristics and dynamics. The surface layer thermal structure (even in wind speeds up to 14 m s–1) underwent a clear diurnal cycle down to at least 20 m, but the rate of dissipation of turbulent kinetic energy ε did not display day/night differences and was negatively or not correlated with the buoyancy frequency N. Below the shallow thermocline step, ε and N covaried, both reaching maximum values in the permanent pycnocline at 80–90 m. Bio-optical properties of the phytoplankton showed different responses to the different physical environments in the two layers. The initial slope of the relationship between photosynthetic rate and irradiance differed significantly between the two layers; and the phytoplankton in the surface layer displayed strong midday inhibition of fluorescence yield down to 30 m. On the one calm day, both the diurnal thermal signal and the fluorescence inhibition were confined to the top few meters, indicating that the deeper penetration on other days was due to near-surface effects being redistributed throughout the upper layer by wind mixing. The turbulence within the permanent pycnocline appeared to be anisotropic down to viscous scales, effectively eliminating vertical turbulent exchange. Such anisotropy in highly stable layers may favor persistence of “microzones” of enriched nutrients but it precludes calculation from microstructure measurements of accurate estimates of the vertical coefficient of turbulent diffusion Kz, required to estimate the vertical flux of dissolved nitrate through the permanent pycnocline

Simulation Study of TenTen: A new Multi-TeV IACT array

TenTen is a proposed array of Imaging Atmospheric Cherenkov Telescopes (IACT) optimized for the gamma ray energy regime of 10 TeV to 100 TeV, but with a threshold of ~1 to a few TeV. It will offer a collecting area of 10 km2 above energies of 10 TeV. In the initial phase, a cell of 3 to 5 modest-sized telescopes, each with 10-30 m2 mirror area, is suggested for an Australian site. A possible expansion of the array could comprise many such cells. Here we present work on configuration and technical issues from our simulation studies of the array. Working topics include array layout, telescope size and optics, camera field of view, telescope trigger system, electronics, and site surveys.Comment: 4 pages, 7 figures, submitted to Proceedings of the ICRC 2007, pdf forma

TenTen: A New Array of Multi-TeV Imaging Cherenkov Telescopes

The exciting results from H.E.S.S. point to a new population of gamma-ray sources at energies E > 10 TeV, paving the way for future studies and new discoveries in the multi-TeV energy range. Connected with these energies is the search for sources of PeV cosmic-rays (CRs) and the study of multi-TeV gamma-ray production in a growing number of astrophysical environments. TenTen is a proposed stereoscopic array (with a suggested site in Australia) of modest-sized (10 to 30m^2) Cherenkov imaging telescopes with a wide field of view (8 to 10deg diameter) optimised for the E~10 to 100 TeV range. TenTen will achieve an effective area of ~10 km^2 at energies above 10 TeV. We outline here the motivation for TenTen and summarise key performance parameters.Comment: 4 pages, 2 figures, proceedings of the 30th ICRC, Merida, Mexico, 200

Intercooled Aero-Gas-Turbine Duct Aerodynamics: Core Air Delivery Ducts

The development of radical new aero engine technologies will be key to delivering the step-changes in aircraft environmental performance required to meet future emissions legislation. Intercooling has the potential for higher overall pressure ratios, enabling reduced fuel consumption, and/or lower compressor delivery air temperatures and therefore reduced NOx. This paper considers the aerodynamics associated with the complex ducting system that would be required to transfer flow from the core engine path to the heat exchanger system. The cycle benefits associated with intercooling could be offset by the pressure losses within this ducting system and/or any detrimental effect the system has on the surrounding components. A suitable branched S-shaped duct system has been numerically developed which diffuses and delivers the flow from the engine core to discrete intercooler modules. A novel swirling duct concept was used to locally open larger spacing between certain duct branches in order to provide engine core access whilst hiding the resultant pressure field from the upstream turbomachinery. The candidate duct system was experimentally evaluated on a bespoke low speed, fully annular isothermal test facility. Aerodynamic measurements demonstrated the ability of the design to meet the stringent aerodynamic and geometric constraints

Advanced engine study program

A design and analysis study was conducted to provide advanced engine descriptions and parametric data for space transfer vehicles. The study was based on an advanced oxygen/hydrogen engine in the 7,500 to 50,000 lbf thrust range. Emphasis was placed on defining requirements for high-performance engines capable of achieving reliable and versatile operation in a space environment. Four variations on the expander cycle were compared, and the advantages and disadvantages of each were assessed. Parametric weight, envelope, and performance data were generated over a range of 7,500 to 50,000 lb thrust and a wide range of chamber pressure and nozzle expansion ratio

Timing analysis techniques at large core distances for multi-TeV gamma ray astronomy

We present an analysis technique that uses the timing information of Cherenkov images from extensive air showers (EAS). Our emphasis is on distant, or large core distance gamma-ray induced showers at multi-TeV energies. Specifically, combining pixel timing information with an improved direction reconstruction algorithm, leads to improvements in angular and core resolution as large as ~40% and ~30%, respectively, when compared with the same algorithm without the use of timing. Above 10 TeV, this results in an angular resolution approaching 0.05 degrees, together with a core resolution better than ~15 m. The off-axis post-cut gamma-ray acceptance is energy dependent and its full width at half maximum ranges from 4 degrees to 8 degrees. For shower directions that are up to ~6 degrees off-axis, the angular resolution achieved by using timing information is comparable, around 100 TeV, to the on-axis angular resolution. The telescope specifications and layout we describe here are geared towards energies above 10 TeV. However, the methods can in principle be applied to other energies, given suitable telescope parameters. The 5-telescope cell investigated in this study could initially pave the way for a larger array of sparsely spaced telescopes in an effort to push the collection area to >10 km2. These results highlight the potential of a `sparse array' approach in effectively opening up the energy range above 10 TeV.Comment: Published in Astroparticle Physic

Actividad física en adultos con y sin diabetes en México (ENSANUT MC-2016)

Physical activity patterns play a key role in diabetes development and control. Our aim is to describe and compare physical activity/inactivity behaviors in general population with and without diabetes in Mexico and changes associated with sociodemographic and health variables. Information from the Halfway National Health and Nutrition Survey 2016 (ENSANUT MC-2016) is used. The findings show that adults with diabetes, from 60 to 69 years old, with obesity and living in the Northern Mexico, are more likely to be inactive. As well as have a higher physical inactivity prevalence (p = 0,000) and a lower proportion of high physical activity (p = 0,002) in adults with diabetes than in those without diabetes. We conclude that persons with diabetes trend more towards behaviors associated with physical inactivity and that it is necessary to generate more research that contributes to explain this phenomenon.Los patrones de actividad física de la población son claves en el desarrollo y control de la diabetes y sus complicaciones. El objetivo es describir y comparar comportamientos de actividad/inactividad física en población general con y sin diabetes en México, así como cambios asociados a variables sociodemográficas y de salud. Se utiliza información de la Encuesta Nacional de Salud y Nutrición de Medio Camino 2016 (ENSANUT MC-2016). Los resultados indican que los adultos con diabetes, de 60 a 69 años, con obesidad y que viven en el norte de México, tienen mayor probabilidad de ser inactivos. Así como una prevalencia de inactividad física mayor (p=0,000) y una proporción de alta actividad física menor (p=0,002) en adultos con diabetes que en adultos sin diabetes. Se concluye que la población con diabetes presenta comportamientos asociados a una mayor inactividad física y que es necesario generar más investigación que contribuya a explicar el fenómeno

Phytophthora taxa associated with cultivated Agathosma, with emphasis on the P. citricola complex and P. capensis sp. nov.

Agathosma species, which are indigenous to South Africa, are also cultivated for commercial use. Recently growers experienced severe plant loss, and symptoms shown by affected plants suggested that a soilborne disease could be the cause of death. A number of Phytophthora taxa were isolated from diseased plants, and this paper reports their identity, mating type, and pathogenicity to young Agathosma plants. Using morphological and sequence data seven Phytophthora taxa were identified: the A1 mating type of P. cinnamomi var. cinnamomi, P. cinnamomi var. parvispora and P. cryptogea, the A2 mating type of P. drechsleri and P. nicotianae, and two homothallic taxa from the P. citricola complex. The identity of isolates in the P. citricola complex was resolved using reference isolates of P. citricola CIT groups 1 to 5 sensu Oudemans et al. (1994) along with multi-locus phylogenies (three nuclear and two mitochondrial regions), isozyme analyses, morphological characteristics and temperature-growth studies. These analyses revealed the isolates from Agathosma to include P. multivora and a putative novel species, P. taxon emzansi. Furthermore, among the P. citricola reference isolates the presence of a new species was revealed, described here as P. capensis. Findings of our study, along with some recent other studies, have contributed to resolving some of the species complexity within the P. citricola complex, resulting in the identification of a number of phylogenetically distinct taxa. The pathogenicity of representative isolates of the taxa from Agathosma was tested on A. betulina seedlings. The putative novel species, P. taxon emzansi, and P. cinnamomi var. parvispora were non-pathogenic, whereas the other species were pathogenic to this host