High-energy threshold reaction rates on 0.8 GeV proton-irradiated thick Pb-target

This works presents results of activation-aided determination of threshold reaction rates in 92 209Bi, natPb, 197Au, 181Ta, 169Tm, natIn, 93Nb, 64Zn, 65Cu, 63Cu, 59Co, 19F, and 12C samples and in 121 27Al samples. All the samples were aligned with the proton beam axis inside and outside the demountable 92-cm thick Pb target of 15-cm diameter assembled of 23 4-cm thick discs. The samples were placed on 12 target disks to reproduce the long axis distribution of protons and neutrons. In June 2006, the target was exposed for 18 hours to a 800-MeV proton beam extracted from the ITEP U-10 accelerator. The proton fluence and the proton beam shape were determined using the 27Al(p,x)7Be monitor reaction. The reaction rates were determined by the direct gamma-spectrometry techniques. In total, 1196 gamma-spectra have been measured, and about 1500 reaction rates determined. The measured reaction rates were simulated by the MCNPX code using the following databases: ENDF/B6 for neutrons below 20 MeV, MENDL2 for 20-100 MeV neutrons, and MENDL2P for proton cross sections up to 200 MeV. An acceptable agreement of simulations with experimental data has been found.Comment: 4 pages, 5 figures, 3 tables, only pdf file, to be published in Proc. Int. Conf. on Nucl. Data for Sci. and Technology (ND2007), Nice, France, April 22-27, 200

Residual nuclide formation in 206,207,208,nat-Pb and 209-Bi induced by 0.04-2.6 GeV Protons as well as in 56-Fe induced by 0.3-2.6 GeV Protons

5972 independent and cumulative yields of radioactive residuals nuclei have been measured in 55 thin 206,207,208,nat-Pb and 209-Bi targets irradiated by 0.04, 0.07, 0.10, 0.15, 0.25, 0.6, 0.8, 1.2, 1.4, 1.6, and 2.6 GeV protons. Besides, 219 yields have been measured in 0.3, 0.5, 0.75, 1.0, 1.5, and 2.6 GeV proton-irradiated 56-Fe target. The protons were extracted from the ITEP U-10 synchrotron. The measured data are compared with experimental results obtained elsewhere and with theoretical calculations by LAHET, MCNPX, CEM03, LAQGSM03, CASCADE, CASCADO, and LAHETO codes. The predictive power was found to be different for each of the codes tested, but was satisfactory on the whole in the case of spallation products. At the same time, none of the codes can de-scribe well the product yields throughout the whole product mass range, and all codes must be further improved.Comment: 4 pages, 4 figures, 2 tables, only pdf file, to be published in Proc. Int. Conf. on Nucl. Data for Sci. and Technology (ND2007), Nice, France, April 22-27, 20

Features of atomic and molecular beams passage through capillary systems in the presence of evanescent light waves

A model of the transverse cooling of atoms in the field of a surface light wave inside a glass capillary is considered. The attenuation coefficient for transverse oscillations of atom in a microcapillary is estimated, and the length of effective atom cooling is calculated. A 3D model is constructed. The possibility for the practical application of this phenomenon both to develop the technology of atomic lithography and to fabricate the nanostructures is considered

Social networks and cognitive function in older adults: findings from the HAPIEE study

BACKGROUND: Social networks are associated with better cognitive health in older people, but the role of specific aspects of the social network remains unclear. This is especially the case in Central and Eastern Europe. This study examined associations between three aspects of the social network (network size of friends and relatives, contact frequency with friends and relatives, and social activity participation) with cognitive functions (verbal memory, learning ability, verbal fluency, processing speed, and global cognitive function) in older Czech, Polish, and Russian adults. METHODS: Linear regression estimated associations between baseline social networks and cognitive domains measured at both baseline and follow-up (mean duration of follow-up, 3.5 ± 0.7 years) in 6691 participants (mean age, 62.2 ± 6.0 years; 53.7% women) from the Health, Alcohol and Psychosocial factors In Eastern Europe (HAPIEE) study. RESULTS: Cross-sectional analyses, adjusted for country, age, and sex, showed positive associations of global cognitive function with social activity participation and network size of friends and relatives, but not with contact frequency in either network. Further adjustment for sociodemographic, behavioural, and health characteristics attenuated the associations with network size of relatives (P-trend = 0.074) but not with network size of friends (P-trend = 0.036) or social activities (P-trend< 0.001). In prospective analyses, network size and social activity participation were also linked with better cognition in simple models, but the associations were much stronger for social activities (P-trend< 0.001) than for network size of friends (P-trend = 0.095) and relatives (P-trend = 0.425). Adjustment for baseline cognition largely explained the prospective associations with network size of friends (P-trend = 0.787) and relatives (P-trend = 0.815), but it only slightly attenuated the association with social activities (P-trend< 0.001). The prospective effect of social activities was largely explained by sociodemographic, health behavioural, and health covariates (P-trend = 0.233). Analyses of specific cognitive domains generally replicated the cross-sectional and prospective findings for global cognitive function. CONCLUSIONS: Older Central and Eastern European adults with larger social networks and greater social activities participation had better cognitive function, but these associations were stronger at baseline than over the short-term follow-up