19,753 research outputs found
Extensive Air Shower Radio Detection: Recent Results and Outlook
A prototype system for detecting radio pulses associated with extensive
cosmic ray air showers is described. Sensitivity is compared with that in
previous experiments, and lessons are noted for future studies.Comment: 17 pages, LaTeX, 7 figures, invited talk presented by J. Rosner at
RADHEP-2000 Conference, UCLA, Nov. 16-18, 2000, Proceedings published by AIP.
Some figures and text changed; one reference update
The French ?Earned Income Supplement? (RSA) and back-to-work incentives
RMI, API, unemployment, means-tested benefits, back-to-work incentives.
Multiple discrete soluble aggregates influence polyglutamine toxicity in a Huntington\u27s disease model system
Huntington’s disease (HD) results from expansions of polyglutamine stretches (polyQ) in the huntingtin protein (Htt) that promote protein aggregation, neurodegeneration, and death. Since the diversity and sizes of the soluble Htt-polyQ aggregates that have been linked to cytotoxicity are unknown, we investigated soluble Htt-polyQ aggregates using analytical ultracentrifugation. Soon after induction in a yeast HD model system, non-toxic Htt-25Q and cytotoxic Htt-103Q both formed soluble aggregates 29S to 200S in size. Because current models indicate that Htt-25Q does not form soluble aggregates, reevaluation of previous studies may be necessary. Only Htt-103Q aggregation behavior changed, however, with time. At 6 hr mid-sized aggregates (33S to 84S) and large aggregates (greater than 100S) became present while at 24 hr primarily only mid-sized aggregates (20S to 80S) existed. Multiple factors that decreased cytotoxicity of Htt-103Q (changing the length of or sequences adjacent to the polyQ, altering ploidy or chaperone dosage, or deleting anti-aging factors) altered the Htt-103Q aggregation pattern in which the suite of mid-sized aggregates at 6 hr were most correlative with cytotoxicity. Hence, the amelioration of HD and other neurodegenerative diseases may require increased attention to and discrimination of the dynamic alterations in soluble aggregation processes
Processed Meat and Colorectal Cancer: A Review of Epidemiologic and Experimental Evidence
Processed meat intake may be involved in the etiology of colorectal cancer, a major cause of death in affluent countries. The epidemiologic studies published to date conclude that the excess risk in the highest category of processed meat-eaters is comprised between 20 and 50% compared with non-eaters. In addition, the excess risk per gram of intake is clearly higher than that of fresh red meat. Several hypotheses, which are mainly based on studies carried out on red meat, may explain why processed meat intake is linked to cancer risk. Those that have been tested experimentally are (i) that high-fat diets could promote carcinogenesis via insulin resistance or fecal bile acids; (ii) that cooking meat at a high temperature forms carcinogenic heterocyclic amines and polycyclic aromatic hydrocarbons; (iii) that carcinogenic N-nitroso compounds are formed in meat and endogenously; (iv) that heme iron in red meat can promote carcinogenesis because it increases cell proliferation in the mucosa, through lipoperoxidation and/or cytotoxicity of fecal water. Nitrosation might increase the toxicity of heme in cured products. Solving this puzzle is a challenge that would permit to reduce cancer load by changing the processes rather than by banning processed meat
Wigner crystal diode
We study the transport properties of a Wigner crystal in one- and
two-dimensional asymmetric periodic potential. We show that the Aubry
transition takes place above a certain critical amplitude of potential with the
sliding and pinned phase below and above the transition. Due to the asymmetry
the Aubry pinned phase is characterized by the diode charge transport of the
Wigner crystal. We argue that the recent experimental observations of Aubry
transition with cold ions and colloidal monolayers can be extended to
asymmetric potentials making possible to observe Wigner crystal diode with
these physical systems and electrons on liquid helium.Comment: 11 pages, 19 figures, accepted to Phys Rev
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