12,101 research outputs found
Research in cosmic and gamma ray astrophysics
Discussed here is research in cosmic ray and gamma ray astrophysics at the Space Radiation Laboratory (SRL) of the California Institute of Technology. The primary activities discussed involve the development of new instrumentation and techniques for future space flight. In many cases these instrumentation developments were tested in balloon flight instruments designed to conduct new investigations in cosmic ray and gamma ray astrophysics. The results of these investigations are briefly summarized. Specific topics include a quantitative investigation of the solar modulation of cosmic ray protons and helium nuclei, a study of cosmic ray positron and electron spectra in interplanetary and interstellar space, the solar modulation of cosmic rays, an investigation of techniques for the measurement and interpretation of cosmic ray isotopic abundances, and a balloon measurement of the isotopic composition of galactic cosmic ray boron, carbon, and nitrogen
MARKETING OPPORTUNITIES FOR JAMAICAāS GRAPEFRUIT INDUSTRY
Several Caribbean sugar producing countries are actively looking for viable alternatives to recover some of the expected lost revenues due to the WTO (World Trade Organization) ruling that sugar subsidies in the European Union (EU) are illegal. One alternative worth considering is exporting fresh grapefruits to the EU. This marketing opportunity comes about as the United States of America (U.S.), the worldās leading grapefruit producer and exporter (over half of world production), has suffered a series of recent setbacks (citrus canker, citrus greening diseases, and devastating hurricanes) that threaten the future of that industry. Specifically, grapefruit and pomelo production in the U.S. has declined steadily since 2000 (from 2,506 thousand metric tons in 2000 to only 914 thousand metric tons in 2005). Approximately 25% of U.S. fresh grapefruit exports are directed to Europe, which is the largest grapefruit and pomelo import region (nearly 60% of world grapefruit and pomelo imports). Rising grapefruit prices in the EU due to reduced supplies coming from the US and an increase in the demand for the fruit in the EU could create a marketing opportunities for countries such as Jamaica. The paper discusses the state of the Florida citrus industry with particular reference to grapefruits and the marketing prospects for Jamaican grapefruit exports to Europegrapefruit, marketing, Florida citrus industry, World Trade Organization, CAES, Agribusiness, Agricultural and Food Policy, Crop Production/Industries, Demand and Price Analysis, Financial Economics, International Relations/Trade,
Economic Issues of Invasive Pests and Diseases and Food Safety
The problem of invasive pests and diseases has become more urgent and far more complex today than in the recent past. Increased trade and movement of people, and the opening up of new trade routes have increased opportunities for the spread of invasive species. In addition, mono-cropping systems of cultivation; globalization; increased resistance of pests to pesticides and food safety and environmental concerns have all contributed to the growing complexity of the problem on hand. The economic dimensions of the problem can be viewed from at least two perspectives. First, with regard to the spread and impact of invasive species, particularly how best to provide more comprehensive assessments of impacts of invasions, so as to improve the cost effectiveness and efficiency of publicly funded programs aimed at eradication, control or mitigation of invasive pests and diseases. Second, from the perspective of incorporating more economic analysis and use of economic instruments in designing sanitary and phytosanitary measures. The paper explores some of these issues from an economic perspective. It concludes that incorporating more economic analysis in matters related to biological invasions is desirable, but presents a challenge to economists. Measurement requires data, and success in measurement will require that economists and biological scientists work closer together than they have in the past.sanitary and phytosanitary measures, SPS, invasive species, WTO, economic impact of invasive species, Environmental Economics and Policy, Food Consumption/Nutrition/Food Safety, International Relations/Trade,
Effect of reactor irradiation on Santowax WR : irradiations from 425Ā° F to 800Ā° F at 40% fast neutron fraction
"MIT-334-34."Includes bibliographical referencesM.I.T. DSR Project no. 9819Contract AT(38-1)-33
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Cell viscoelasticity is linked to fluctuations in cell biomass distributions.
The viscoelastic properties of mammalian cells can vary with biological state, such as during the epithelial-to-mesenchymal (EMT) transition in cancer, and therefore may serve as a useful physical biomarker. To characterize stiffness, conventional techniques use cell contact or invasive probes and as a result are low throughput, labor intensive, and limited by probe placement. Here, we show that measurements of biomass fluctuations in cells using quantitative phase imaging (QPI) provides a probe-free, contact-free method for quantifying changes in cell viscoelasticity. In particular, QPI measurements reveal a characteristic underdamped response of changes in cell biomass distributions versus time. The effective stiffness and viscosity values extracted from these oscillations in cell biomass distributions correlate with effective cell stiffness and viscosity measured by atomic force microscopy (AFM). This result is consistent for multiple cell lines with varying degrees of cytoskeleton disruption and during the EMT. Overall, our study demonstrates that QPI can reproducibly quantify cell viscoelasticity
Assessing the potential impact of strengthening food safety regulations on developing countries: The US Food Safety and Modernization Act
This paperās goal is to assess the extent to which producers in Developing Countries have coped stricter US food safety regulations. We approach the question by calculating refusals/imports ratios and their trends for a sample of Developing Countries. We conclude there is a learning process in low value added products.food safety, traceability, value chain analysis, trade, Latin America and the Caribbean, Food Consumption/Nutrition/Food Safety, International Development, International Relations/Trade,
Nucleation and growth control in protein crystallization
The five topics summarized in this final report are as follows: (1) a technique for the expedient, semi-automated determination of protein solubilities as a function of temperature and application of this technique to proteins other than lysozyme; (2) a small solution cell with adjustable temperature gradients for the growth of proteins at a predetermined location through temperature programming; (3) a microscopy system with image storage and processing capability for high resolution optical studies of temperature controlled protein growth and etching kinetics; (4) growth experiments with lysozyme in thermosyphon flow ; and (5) a mathematical model for the evolution of evaporation/diffusion induced concentration gradients in the hanging drop protein crystallization technique
Ion bombardment experiments suggesting an origin for organic particles in pre-cometary and cometary ices
During the Giotto and Vega encounters with Comet Halley both organic particles called CHON and energetic ions were detected. The acceleration of ions to hundreds of keV in the vicinity of the bow shock and near the nucleus may be a demonstration of a situation occurring in the early solar system (perhaps during the T Tauri stage) that led to the formation of organic particles only now released. Utilizing a Van de Graaff accelerator and a target chamber having cryogenic and mass spectrometer capabilities, frozen gases were bombarded at 10 K with 175 keV protons with the result that fluffy solid material remains after sublimation of the ice. Initial experiments were carried out with a gas mixture in parts of 170 carbon monoxide, 170 argon, 25 water, 20 nitrogen, and 15 methane formulated to reflect an interstellar composition in experiments involving the freezing out of the products of a plasma. The plasma experiments resulted in a varnish-like film residue that exhibited luminescence when excited with ultraviolet radiation, while the ion bombardment created particulate material that was not luminescent
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