210 research outputs found
Precision wave-length measurements of the 1.1- and 1.3-Mev lines of CO60 with the two-meter focusing curved-crystal spectrometer
Recent improvements in the two-meter focusing curved-crystal gamma-ray spectrometer are described which have extended its quantum energy range well above 1 Mev and have also yielded much better luminosity and resolving power than were obtained initially. The improved components are (1) the crystal holder whose aperture and resolving power have been nearly doubled and (2) the collimator the new model of which can now discriminate between the reflected and transmitted beams when these differ in direction by only 8 minutes of arc, a threefold improvement over our first model. Our plans for further possible improvements and the factors governing these are also discussed. Wavelengths of two gamma-rays emitted following ÎČ-decay of Co60 have been measured with this new equipment using a source of about 50 mc strength and found to have values of (9.308±0.005)Ă10-11 cm and (10.580±0.005)Ă10-11 cm corresponding to quantum energies of 1.3316±0.0010 Mev and 1.1715±0.0010 Mev, respectively. The lines appear to have equal intensities. The integrated reflection coefficient of the (310) planes of the curved-quartz crystal still appears to follow a λ2-dependence on wave-length down to 9 x.u. the shortest so far observed
Staff Perceptions of Risk for Prison Rape Perpetration and Victimization
Copyright © 2012 SAGE Publications, http://tpj.sagepub.com Used by permission
Fundamental Constants of Physics [Book Review]
Book review of: Fundamental Constants of Physics. E. R. COHEN, K. M.
CROWE, AND J. W. M. DuMOND. Pp. 287+ix. Interscience
Monographs in Physics and Astronomy,
Volume I. Interscience Publishers, Inc., New York,
1957
Leftovers:The presence of manufacture-derived aquatic lipids in Alaskan Pottery
Lipids preserved within the walls of ancient pottery vessels are routinely analysed to reveal their original contents. The provenience of aquatic lipids in pottery is generally connected to vessel function (e.g., for cooking or storing fish, shellfish and aquatic mammals). However, ethnographic reports from early historic Alaska mention the use of aquatic oils for waterproofing low-fired pottery. Results of lipid residue studies on Alaskan pottery reflect an exclusive function of pottery to process aquatic resources. However, can one be sure these residues are the product of vessel function and not a remnant of the manufacturing process? The study presents the results of an experiment where the preservation of aquatic lipids during the firing process at different temperatures was measured. It was found that nearly all lipids were removed at firing temperatures of ℠400°C. Petrographic analysis of Alaskan pottery samples indicates that firing temperatures were generally > 550°C but < 800°C. The contribution of pre-firing manufacture-derived lipids to samples fired at these temperatures may be regarded as negligible. While the possible presence of aquatic lipids from post-firing surface treatments cannot be excluded, such treatments appear unnecessary for well-fired pottery.</p
Latex Particle Size Determination Using Diffraction Peaks Obtained with the Point Focusing XâRay Monochromator
Internally Electrodynamic Particle Model: Its Experimental Basis and Its Predictions
The internally electrodynamic (IED) particle model was derived based on
overall experimental observations, with the IED process itself being built
directly on three experimental facts, a) electric charges present with all
material particles, b) an accelerated charge generates electromagnetic waves
according to Maxwell's equations and Planck energy equation and c) source
motion produces Doppler effect. A set of well-known basic particle equations
and properties become predictable based on first principles solutions for the
IED process; several key solutions achieved are outlined, including the de
Broglie phase wave, de Broglie relations, Schr\"odinger equation, mass,
Einstein mass-energy relation, Newton's law of gravity, single particle self
interference, and electromagnetic radiation and absorption; these equations and
properties have long been broadly experimentally validated or demonstrated. A
specific solution also predicts the Doebner-Goldin equation which emerges to
represent a form of long-sought quantum wave equation including gravity. A
critical review of the key experiments is given which suggests that the IED
process underlies the basic particle equations and properties not just
sufficiently but also necessarily.Comment: Presentation at the 27th Int Colloq on Group Theo Meth in Phys, 200
Dietary garlic and hip osteoarthritis: evidence of a protective effect and putative mechanism of action
Background Patterns of food intake and prevalent osteoarthritis of the hand, hip, and knee were studied using the twin design to limit the effect of confounding factors. Compounds found in associated food groups were further studied in vitro. Methods Cross-sectional study conducted in a large population-based volunteer cohort of twins. Food intake was evaluated using the Food Frequency Questionnaire; OA was determined using plain radiographs. Analyses were adjusted for age, BMI and physical activity. Subsequent in vitro studies examined the effects of allium-derived compounds on the expression of matrix-degrading proteases in SW1353 chondrosarcoma cells. Results Data were available, depending on phenotype, for 654-1082 of 1086 female twins (median age 58.9 years; range 46-77). Trends in dietary analysis revealed a specific pattern of dietary intake, that high in fruit and vegetables, showed an inverse association with hip OA (p = 0.022). Consumption of 'non-citrus fruit' (p = 0.015) and 'alliums' (p = 0.029) had the strongest protective effect. Alliums contain diallyl disulphide which was shown to abrogate cytokine-induced matrix metalloproteinase expression. Conclusions Studies of diet are notorious for their confounding by lifestyle effects. While taking account of BMI, the data show an independent effect of a diet high in fruit and vegetables, suggesting it to be protective against radiographic hip OA. Furthermore, diallyl disulphide, a compound found in garlic and other alliums, represses the expression of matrix-degrading proteases in chondrocyte-like cells, providing a potential mechanism of action
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