Micro-geodynamics of the Karakoram Fault Zone, Ladakh, NW Himalaya

Microgeodynamics relates grain-scale deformation microstructures to macroscopic tectonic processes. Here the microgeodynamic approach combines optical and electron microscopy, including electron backscattered diffraction (EBSD), with field geology, geothermobarometry and microphysical modelling to study fault rocks deformed within a major continental strike-slip fault to quantify changes in fault zone structure and rheology with crustal depth. The overall thesis rational therefore is to test existing fault models against an exhumed example of a continental strike-slip fault zone, namely the central Karakoram Fault Zone (KFZ), NW India. This approach establishes changes in deformation processes with depth in the upper- to mid-crust and suggests that a range of fault weakening mechanisms have reduced fault rock shear strengths, typified by friction coefficients of 0.3-0.4. Metamorphic petrology and geothermobarometry are used to place the KFZ in the context of regional tectono-metamorphic evolution. It is shown using diagnostic microstructures and pressure-temperature-time paths that the fault initiated after peak metamorphism (677-736°C, 875-1059 MPa) and subsequent migmatisation (688±44°C, 522±91 MPa) and leucogranite emplacement (448±100 MPa). Retrograde phyllonites formed during later strike-slip deformation are investigated in detail using EBSD, geothermometry and microphysical modelling. The phyllonites formed at 351±34°C and had low shear strength (<30 MPa) during frictional-viscous flow. EBSD is also used to derive a novel strain proxy based on quartz crystal preferred orientation intensity. Application of this method distinguishes deformation distributions in transects across the KFZ. Deformation intensity varies from <0.2 in essentially undeformed domains to 1.6 within shear zone strands formed at 500-550°C and c. 15 km depth. Evaluation of the history of the KFZ suggests that whilst it plays a relatively minor role in accommodating India-Asia collision, it can nevertheless be used as an analogue for major continental strike-slip fault zone structure

Aspects of the nutritional physiology of the perlemoen Haliotis midae (L.) and red abalone H. rufescens (Swainson)

The source of abalone for human consumption has shown a dramatic shift away from wild-capture fisheries in the last 30 years, with over 90% of global production now coming from aquaculture. Farmers initially relied on the natural food of abalone (macroalgae) as a culture feed, though in regions where macroalgae availability was limiting, the need to develop formulated feeds was evident. Extensive research effort has led to the development of a number of formulated feed products currently employed in the industry. These feeds, however, differ markedly from the mixed macroalgal diets that abalone have evolved to utilise, particularly in terms of protein content and carbohydrate structure. The degree to which the nutritional physiology of abalone responds to these novel formulated diets, with and without macroalgal supplementation, was investigated in the current study. A multifaceted approach, combining growth trials, stable isotope nutrient tracers and metabolic experiments, was employed to gain insight into the post-absorption dynamics and utilisation of dietary nutrients under varying dietary regimes of fresh macroalgae and formulated feed. Growth trials conducted with both Haliotis rufescens and H. midae showed significantly higher growth and protein utilisation efficiency for abalone fed macroalgal diets compared to formulated feeds. Furthermore, when formulated feeds were supplemented with macroalgae to form combination diets, growth and the utilization of protein was improved compared to the formulated-feed-only diet. The poor utilisation of protein by H. midae fed the formulated feed could be traced, using a method combining stable isotope bio-markers with a Bayesian mixing model (SIAR), to the low incorporation of the fishmeal component of protein in the diet. The marked postprandial drop in the O:N ratio on abalone fed formulated feeds indicate that the protein was being diverted into catabolic metabolic pathways. The metabolic cost of digestion, termed specific dynamic action (SDA), was negated as a factor in the improved growth of abalone fed macroalgal diets, with the SDA coefficient 2.1 times that observed for formulated feed. Furthermore, the postprandial haemolymph glucose concentration (HGC) in H. midae was elevated when fed formulated feed compared to macroalgae. The high levels of circulating glucose are likely a result of the structure the carbohydrate source in formulated feeds and stimulate the deposition of glycogen through the allosteric control of glycogen synthase. Formulated feeds produced higher cooked meat yields in canning simulation trials, suggesting that muscle glycogen content may indirectly play a role in increasing canning yields through the displacement of collagen. The results of these empirical studies are synthesised under key themes, discussed within the context of their potential commercial relevance and future research directions are highlighted

The influence of potato leafhopper-induced injury on crop developmental physiology and economic utility of alfalfa

The impact of potato leafhopper (PLH), Empoasca fabae (Harris), feeding on the yield and quality of alfalfa, Medicago sativa L., was investigated. Research was designed to characterize the physiological response of PLH-induced hopperburn , with emphasis on individual plant components (i.e., stems and leaves). Field trials were conducted (one in 1984 and two in 1985) with field cages to establish known densities of PLH at two periods during second growth of \u27Blazer\u27 alfalfa. Plants were intensively sampled weekly to monitor stem and leaf development rates;Components comprising biomass yield were significantly altered as a result of PLH feeding. Although stem density was unchanged, the number of mainstem nodes and stem height were reduced. The effective leaf area index, which considers only non-chlorotic leaf tissue, was also significantly reduced for all infested plots. Growth rates for stem and leaf components indicate that initial delays in development from PLH stress are mostly compensated for later in the regrowth period;Measurements of forage quality, including digestibility, crude protein, and cell-wall concentration, were determined for all plots. Results demonstrate digestibility and cell-wall concentration are generally unaltered, but that leaf proteins are reduced. The relatively insignificant decline in quality is probably a result of the reduced stem component, offsetting the declines in leaf quality. Similar trends were noted for calculations of relative feed value, digestible dry matter intake, and digestible Oil, Gas, and Energy;The aggregate response in nutritional yield (biomass x quality) is significantly altered by PLH feeding. At harvest, the most significant correlation with PLH density was determined to be rate of phenological development. Economic-injury levels (EIL\u27s) were calculated for alfalfa infested early and late based on days delay past first bloom. The calculations were made on a protein, digestible energy, and biomass equivalency for various control costs and market values;In order to evaluate the value of a PLH pest management system for specialized uses of alfalfa, damaged and undamaged characterizations were utilized in least-cost rationing models to refine the estimate of crop utility. The calculated values for crop utility enhance the use of economic decision indices for forage crops

Cooling neutron stars and superfluidity in their interiors

We study the heat capacity and neutrino emission reactions (direct and modified Urca processes, nucleon-nucleon bremsstrahlung, Cooper pairing of nucleons) in matter of supranuclear density of the neutron star cores with superfluid neutrons and protons. Various superfluidity types are analysed (singlet-state pairing and two types of triplet-state pairing, without and with nodes of the gap at a nucleon Fermi surface). The results are used for cooling simulations of isolated neutron stars. Both, the standard cooling and the cooling enhanced by the direct Urca process, are strongly affected by nucleon superfluidity. Comparison of cooling theory of isolated neutron stars with observations of their thermal radiation may give stringent constraints on the critical temperatures of the neutron and proton superfluidities in the neutron star cores.Comment: LaTeX, 85 pages, 23 figures, Physics - Uspekhi (accepted

The Effect Of Anti prostaglandin COX2 on NileTilapia Fish Growth Rate and Mortality Rate

Several studies have been conducted to detect the direct effect of inhibiting the aromatase activity, the rate limiting enzyme that converts androgens to estrogens needed for ovarian differentiation in fish to overcome the immediate need for a more environmentally friendly substitute of methyl testosterone. Cyclooxygenase (COX2)- inhibitors are potent and irreversible inhibitors of the COX2 pathway and since studies on human breast cancer cells shows that they decrease aromatase messenger ribonucleic acid (mRNA) expression at the transcriptional level we tested the effects of supplementation of COX2-inhibitors (Etodolac and Etoricoxib) in the diets of fry tilapia on growth rate, and mortality.On the other hand, human and veterinary pharmaceuticals have been shown to occur in considerably high amounts in sewage treatment plant (STP) effluents and surface waters, with the non-steroidal anti inflammatory drugs representing one of the most commonly detected compounds. Information concerning possible ecotoxicological risks of these substances is rather scarce. So far there are no data available on their possible effects in fish after prolonged exposure. Thus, highlight on Etoricoxib pharmacokinetics was carried out by determination of Etoricoxib in fish feces using HPLC. The study was carried out at the Aquaculture research laboratory, in AlQuds University, Jerusalem. At an age of 8 days post – hatched 30 genetically mixed population of Oreochromis. niloticus larvae were stocked in duplicate, into aquariums each with a capacity of ≈ 45L in a closed system. Treatments included 5 different experimental diets and one standard diet serving as control with two repeats for each group from 0.5 % groups of diets. The test diets were prepared by mixing 600 mg of etodolac with 20g,60 g,30 g commercial feed, to achieve (0.5% etodolac,1%etodolac, 2% etodolac)concentrations respectivelythe same process was done to the etoricoxib by mixing 90 mg of etoricoxib with 18 g, 9 g, commercial feed, to achieve (0.5% etoricoxib,1% etoricoxib) concentrations respectively. Another experiment was conducted using 10 adult mixed populations at age of 2 months stocked in triplicate in a closed system and, treated as above. Feeding started on the same day of stocking and fish were fed once daily. Feed was adjusted according to fish weight, by 10 % of their weight during the first four weeks and 5% of their body weight after changes of all diets to control diet. Fish were weighted every week and counted in each aquarium to determine survival rate during 12 weeks period. Individual fish in each aquarium was weighted to the nearest 0.1 g using adigital scale. The growth rate (GR) was determined using linear regression: yt = a + bxt, where yt is the average total weight (g) of the fishes at time t and a is the average weight (g) of fishes at the start of the experiment. Results showed that the different growth rate parameters (final body weight, weight gain and growth rate (GR) of O niloticus fed with selective COX2 inhibitor Etodolac and Etoricoxib respectively were significantly affected with the highest growth rate obtained with the 0.5% etodolac followed by etoricoxib 0.5% followed by untreated sample. However, no increase or decrease of growth in mixed adult population was observed. Growth rate increased with increasing concentrations with the highest growth rate in the aquarium treated with (2% Etodolac) followed by (1% Etodolac), but (1% Etoricoxib) showed a decreased growth rate compared to standard which could indicates a toxic potential toward fish at this concentration. In addition, no peak for Etoricoxib was detected on HPLC in feces samples collected after half an hour, 1 hour, 2 hours, 3 hours and 4 hours,24 hours following treatment with 1% etoricoxib diet in 4 months age tilapia. This reflected, that Etoricoxib, was well absorbed by tilapia, extensively metabolized with no unchanged fraction excreted, or may undergo enter hepatic circulation, increasing further its toxic potential. No mortality was observed in adult mixed population. In fish fry there were no differences in mortality rates between (0.5% Etodolac), and (0.5% Etoricoxib) treatments, but survival rate (96.6% and 90%) were improved compared to control (86.6%, 83.3%) during the experimental feeding. Higher mortalities were shown as concentrations increase with (1%Etoricoxib), (1% Etodolac) and (2% Etodolac). These results indicated that the inclusion of selectiveCOX-2 inhibitor in fish diet efficiency was maximally exerted during critical period of sexual differentiation, which occurs in tilapia fry between 2 and 6 weeks after spawning. After finishing of this period there was no effect on the growth rate. Thus, COX inhibitors could modulate aromatase activity needed for proper sexual development and reproduction during the crucial period. Furthermore, this is the first time to our knowledge we test the effects of these agents on fry teleosts during the crucial period of sexual development which points to possible alterations in reproduction following chronic exposure to these drugs at an early stage in contaminated surface water. Subsequent field investigations in normal aquaculture bonds are needed to confirm these results in larger population, using different classes of COX-inhibitors at different concentrations.

Reports of planetary astronomy, 1991

A collection is presented of summaries designed to provide information about scientific research projects conducted in the Planetary Astronomy Program in 1990 and 1991, and to facilitate communication and coordination among concerned scientists and interested persons in universities, government, and industry. Highlights of recent accomplishments in planetary astronomy are included

NASA Tech Briefs, November 2002

Topics include: a technology focus on engineering materials, electronic components and systems, software, mechanics, machinery/automation, manufacturing, bio-medical, physical sciences, information sciences book and reports, and a special section of Photonics Tech Briefs

Predicting individual stock returns using optimized neural networks

I investigate individual monthly U.S. stock return predictability through a comparative study on neural networks and ordinary least squares benchmarks, using a predictor set of 102 lagged firm characteristics and the market return from 1980 to 2018. I find monthly out-of-sample (OOS) R2 of 0.80% for the best neural network, confirming similar findings of marginal predictability from existing literature applying machine learning to empirical finance. OOS R2 increases to 7.12% for the best neural network, when considering average market return predictability using market return predictions constructed bottom-up from equal-weighting individual stock predictions. I also find significant monthly four-factor alphas of 1.55% and annualized Sharpe ratios of 2.62 on long-short top-bottom decile portfolios sorted on predicted returns – not taking into account trading costs. Investigating variable importances within neural networks reveals that networks using Rectifier as their activation function focus on momentum and liquidity variables, similar to existing findings, but networks using Maxout focus on firm fundamentals and risk measures instead – a new observation for the anomalies literature. Lastly, my findings confirm that return anomalies are stronger in small stocks, and prediction performance is generally stronger during market turbulence