CFD designed experiments for shock wave/boundary layer interactions in hypersonic ducted flows

The successful operation of scramjet combustors requires compression of hypersonic viscous ducted flows and avoidance of separation effects which may preclude steady flow. Separation effects in scramjet inlets and combustors can be caused by shock wave/boundary layer interactions. The hypersonic turbulent flow experiments needed are inherently difficult to design because of the high sensitivity of the macroscopic flow parameters which cause the turbulent flow processes. Hence computational fluid dynamics (CFD) is a useful tool for the design and characterisation of models in hypersonic flows before model construction. One of the greatest challenges however is to ensure that the flow is being modeled accurately. In this paper, a commercial code has been used to model an experiment performed in a small reflected shock tunnel using a Mach 8.65 condition. The research being carried out in this facility is concerned with separation due to incident shock wave/turbulent boundary interactions in hypersonic ducted flows. The model is designed to produce two conical shocks which interact with a turbulent boundary layer and it is instrumented with pressure transducers and thin film heat transfer gauges. The measurements have allowed graphical representation of unseparated static wall pressure and heat flux prior to and after each wall interaction. The results of the simulations are in excellent agreement with the experimental data. The code has been applied to identify parameter boundaries in the design of a model of similar scale that will produce separated flow

The amino acid sensitive TOR pathway from yeast to mammals

AbstractThe target of rapamycin (TOR) is an ancient effector of cell growth that integrates signals from growth factors and nutrients. Two downstream effectors of mammalian TOR, the translational components S6K1 and 4EBP1, are commonly used as reporters of mTOR activity. The conical signaling cascade initiated by growth factors is mediated by PI3K, PKB, TSC1/2 and Rheb. However, the process through which nutrients, i.e., amino acids, activate mTOR remains largely unknown. Evidence exists for both an intracellular and/or a membrane bound sensor for amino acid mediated mTOR activation. Research in eukaryotic models, has implicated amino acid transporters as nutrient sensors. This review describes recent advances in nutrient signaling that impinge on mTOR and its targets including hVps34, class III PI3K, a transducer of nutrient availability to mTOR

SPORTS ANXIETY OF ATHLETES AND THEIR COPING SKILLS

This study examined sports anxiety and coping skills in high school students from the Davao del Sur Division using online survey questionnaires for 101 participants who are high school students from three major public schools in Davao del Sur. To address the study hypotheses, correlation analysis using Pearson's product-moment correlation, mean, and linear regression was used. Sports Anxiety among athletes is moderate; the results also showed that the athletes' coping skills are at a high level; In addition, there is a significant correlation between sports anxiety and the coping strategies of athletes; However, there is no significant impact of the range of sports anxiety on athletes' coping skills.  Article visualizations

Policy evaluation with temporal differences: a survey and comparison

Policy evaluation is an essential step in most reinforcement learning approaches. It yields a value function, the quality assessment of states for a given policy, which can be used in a policy improvement step. Since the late 1980s, this research area has been dominated by temporal-difference (TD) methods due to their data-efficiency. However, core issues such as stability guarantees in the off-policy scenario, improved sample efficiency and probabilistic treatment of the uncertainty in the estimates have only been tackled recently, which has led to a large number of new approaches. This paper aims at making these new developments accessible in a concise overview, with foci on underlying cost functions, the off-policy scenario as well as on regularization in high dimensional feature spaces. By presenting the first extensive, systematic comparative evaluations comparing TD, LSTD, LSPE, FPKF, the residual- gradient algorithm, Bellman residual minimization, GTD, GTD2 and TDC, we shed light on the strengths and weaknesses of the methods. Moreover, we present alternative versions of LSTD and LSPE with drastically improved off-policy performance

Pathogenicity of nectriaceous fungi on avocado in Australia

Black root rot is a severe disease of young avocado trees in Australia causing black necrotic roots, tree stunting, and leaf drop prior to tree death. Nectriaceous fungi (Nectriaceae, Hypocreales), are commonly isolated from symptomatic roots. This research tested the pathogenicity of 19 isolates from Calonectria, Cylindrocladiella, Dactylonectria, Gliocladiopsis, and Ilyonectria, spp. collected from young avocado trees and other hosts. Glasshouse pathogenicity tests with ‘Reed’ avocado (Persea americana) seedlings confirmed that Calonectria ilicicola is a severe pathogen of avocado, causing stunting, wilting, and seedling death within 5 weeks of inoculation. Isolates of C. ilicicola from peanut, papaya, and custard apple were also shown to be aggressive pathogens of avocado, demonstrating a broad host range. An isolate of a Calonectria sp. from blueberry and avocado isolates of Dactylonectria macrodidyma, D. novozelandica, D. pauciseptata, and D. anthuriicola caused significant root rot but not stunting within 5 to 9 weeks of inoculation. An isolate of an Ilyonectria sp. from grapevine closely related to Ilyonectria liriodendri, and avocado isolates of Cylindrocladiella pseudoinfestans, Gliocladiopsis peggii, and an Ilyonectria sp. were not pathogenic to avocado

Nuclear weapons fallout 137Cs in temperate and tropical pine forest soils, 50 years post-deposition

Following nuclear releases to the environment, 137Cs (half-life 30 years) is a long-term contaminant of many ecosystems, including forests. We recently sampled soils under pine forests in temperate and tropical climates to test the hypothesis that migration of 137Cs, 50 years after nuclear weapons fallout, is coupled with organic matter (OM) accumulation in these soils. Depth profiles of 137Cs, naturally-occurring 210Pb and weapons-derived 241Am were measured. After 50 years, migration of 137Cs into the temperate and tropical soils is limited to half-depths of 7–8 cm and 2–3 cm, respectively. At both locations, most 137Cs is associated with OM that accumulated from the early to mid-1960s. Illite, which immobilises radiocaesium, was undetectable by X-ray diffraction in the layer of peak 137Cs accumulation in the temperate forest soil, but apparent in the zone of peak concentration in the tropical soil. Data indicate that long-term (50 year) fate of 137Cs in organic-rich, temperate forest soil is coupled with OM accumulation; fixation of 137Cs by illite is more important in the tropical forest soil where OM is rapidly decomposed. Models of long-term radiocaesium migration in forest soils should explicitly account for the role of OM, especially when considering forests under contrasting climatic regimes

A novel spatio-temporal scale based on ocean currents unravels environmental drivers of reproductive timing in a marine predator

Life-history strategies have evolved in response to predictable patterns of environmental features. In practice, linking life-history strategies and changes in environmental conditions requires comparable space–time scales between both processes, a difficult match in most marine system studies. We propose a novel spatio-temporal and dynamic scale to explore marine productivity patterns probably driving reproductive timing in the inshore little penguin (Eudyptula minor), based on monthly data on ocean circulation in the Southern Ocean, Australia. In contrast to what occurred when considering any other fixed scales, little penguin's highly variable laying date always occurred within the annual peak of ocean productivity that emerged from our newly defined dynamic scale. Additionally, local sea surface temperature seems to have triggered the onset of reproduction, acting as an environmental cue informing on marine productivity patterns at our dynamic scale. Chlorophyll-a patterns extracted from this scale revealed that environment factors in marine ecosystems affecting breeding decisions are related to a much wider region than foraging areas that are commonly used in current studies investigating the link between animals' life history and their environment. We suggest that marine productivity patterns may be more predictable than previously thought when environmental and biological data are examined at appropriate scales.Peer reviewe

Sililoquies

I believe that to be most fully successful and rewarding, a work of art must stimulate the viewer's imagination and challenge him to investigate. It must be able to suggest that there is more to the work than may be immediately apparant through cursory visual examination (if that, indeed, is the case), and provide the viewer with enough information to be able to at least attempt to discover the more subtle workings of the piece. This can be accomplished through provocative use of materials, forms, titles, and installation in any and all combinations. In the most ideal of situations, the viewer will be enticed to draw from his own background and experience to arrive at a conclusion which very closely resembles the artist's intent. In Soliloquies I have presented an environment composed of a suite of three major works using latex rubber as the primary material. As the title implies, these works are very personal and, in fact, are largely autobiographical. They represent my reactions to an extremely difficult and emotionally painful period earlier in my life with which I have only recently been able to deal objectively.</p

Large-area submillimeter resolution CdZnTe strip detector for astronomy

We report the first performance measurements of a sub-millimeter CdZnTe strip detector developed as a prototype for space-borne astronomical instruments. Strip detector arrays can be used to provide two-dimensional position resolution with fewer electronic channels than pixellated arrays. Arrays of this type and other candidate technologies are under investigation for the position-sensitive backplane detector for a coded-aperture telescope operating in the range of 30 - 300 keV. The prototype is a 1.4 mm thick, 64 multiplied by 64 stripe CdZnTe array of 0.375 mm pitch in both dimensions, approximately one square inch of sensitive area. Pulse height spectra in both single and orthogonal stripe coincidence mode were recorded at several energies. The results are compared to slab- and pixel-geometry detector spectra. The room-temperature energy resolution is less than 10 keV (FWHM) for 122 keV photons with a peak-to-valley ratio greater than 5:1. The response to photons with energies up to 662 keV appears to be considerably improved relative to that of previously reported slab and pixel detectors. We also show that strip detectors can yield spatial and energy resolutions similar to those of pixellated arrays with the same dimensions. Electrostatic effects on the pulse heights, read-out circuit complexity, and issues related to design of space borne instruments are also discussed