Carbonaceous chondrites: Early irradiation and Pu-244 fission records

The carbonaceous meteorites were studied. The studies which were conducted have evolved from investigations of early irradiation to mineralogic and petrologic studies of refractory inclusions and to an examination of the time scales of alteration processes on the parent bodies. The attached listing of papers and abstracts provide the details

Seawater strontium isotopes at the Cretaceous-Tertiary boundary

Anomalously high values of Seawater Sr-87/Sr-86 near the Cretaceous-Tertiary (K-T) boundary have been reported. However, few of the data from the literature are from a single continuous section, and perhaps the most complete study of the boundary region, from a shallow marine limestone sequence in Alabama, showed elevated Sr-87/Sr-86 but no pronounced spike. Thus, in order to investigate the cause of the change in strontium isotopic composition, it is important to determine the exact nature and magnitude of the increase by studying in detail continuous sections through the boundary. If there is indeed a Sr isotope spike at the K-T boundary, it requires the addition of a large amount of radiogenic Sr to the oceans over a short time period, a phenomenon that may be linked to other large-scale environmental disturbances which occurred at that time. In order to address this question, a high-resolution strontium isotope study of foraminifera from three Deep Sea Drilling Project (DSDP) cores which recovered the K-T boundary section: Site 356 in the South Atlantic, Site 384 in the North Atlantic and Site 577 from the Shatsky Rise in the Pacific was initiated. The isotope measurements are being made on either single or small numbers of forams carefully picked and identified and in most cases examined by SEM before analysis. Because this work is not yet complete, conclusions drawn here must be viewed as tentative. They are briefly discussed

BIOMECHANICAL AND PHYSIOLOGICAL MEASURES OF TEEN-AGED BADMINTON PLAYERS

Badminton books, coaching manuals, and instructional pamphlets all attest to the importance of cardio-respiratory endurance, strength, and flexibility and many provide training methods and schedules. For example, a training schedule for elite badminton players has been compiled by Canada's national team coach, but no norms are provided which would indicate acceptable levels of achievement (Gilliland, 1987). There appear to be no values available to indicate extraordinary, or even acceptable, levels ofperfonnance for badminton players. In one of the manuals (the Level III Training Manual of the Canadian Badminton Association by Reed, 1981:29), reference is made to some nonns including a badminton four-corner fitness test developed by the University of Ottawa Research Group, that provides heart rate recovery, and recovery speed statistics for adult and junior competitors. However, those norms are specific to the four-corner test and provide only a rough indication ofthe demand on the cardio-respiratory system

Physical Activity Change of English, French and Chinese Speaking Immigrants in Ottawa and Gatineau, Canada

SAP is an open access publisherOBJECTIVES: The multicultural study aims at examining Physical Activity Change of English, French and Chinese speaking immigrants in Ottawa and Gatineau, Canada, and identifying demographic factors that correlate with the change and impact the change. METHODS: 810 immigrants of three language sub-groups were recruited by purposive-sampling. Using self-reports, respondents answered questions regarding Physical Activity Change and Demography in Multicultural Lifestyle Change Questionnaire of English, French or Chinese version. Data were analyzed statistically in percentage, correlation, regression and factor analysis. RESULTS: Immigrants of different gender, language and category sub-groups exhibited different rates in Physical Activity Change, and different language sub-groups displayed different Physical Exercise Items rates after immigration, but no statistical difference between the rates. Physical Activity Change (Physical Activity Behavior Change + Physical Activity Belief Change) was negatively correlated with Gender, Category of Immigration, Employment Status and Primary Occupation. Physical Activity Behavior Change was negatively correlated with Age, Gender, Category of Immigration, Employment Status and Primary Occupation. Age, Gender, Category of Immigration and Employment Status significantly impacted Physical Activity Change. Mother Tongue, Age, Gender, Category of Immigration and Employment Status significantly impacted Physical Activity Behavior Change. Two factors (factor one: physical activity behavior change factor and factor two: physical activity belief change factor) influenced significantly Physical Activity Change. Factor one exposed more significant effect than factor two. CONCLUSIONS: Different immigrant sub-groups experienced different Physical Activity Change and three language sub-groups presented different physical activity patterns after immigration. Age, Gender, Category of Immigration, Employment Status and Primary Occupation were main factors impacting significantly Physical Activity Change. Mother Tongue was an important factor influencing significantly Physical Activity Behavior Change. Culture and acculturation were relating contributing factors. Data may provide evidence and implication for physical exercising policy-making and policy-revising in Canada

Irregular HF radio propagation on a subauroral path during magnetospheric substorms

The impact of the main ionospheric trough, sporadic structures, gradients and inhomogeneities of the subpolar ionosphere during substorms on the signal amplitude, azimuthal angles of arrival, and propagation modes for the radio path Ottawa (Canada)-St. Petersburg (Russia) was considered. This subauroral path with the length of about 6600 km has approximately an east-west orientation. The main goals are to carry out numerical modeling of radio propagation for the path and to compare the model calculations with experimental results. Wave absorption and effects of focusing and divergence of rays were taken into consideration in the radio wave modeling process. The following basic results were obtained: The signal amplitude increases by 20–30 dB 1–1.5 h before the substorm expansion phase onset. At the same time the signal azimuth deviates towards north of the great circle arc for the propagation path. Compared with quiet periods there are effects due to irregularities and gradients in the area of the polar edge of the main ionospheric trough on the passing signals. Propagation mechanisms also change during substorms. The growth of signal amplitude before the substorm can be physically explained by both a decrease of the F2-layer ionization and a growth of the F2-layer height that leads to a decrease of the signal field divergence and to a drop of the collision frequency. Ionospheric gradients are also important. This increase of signal level prior to a substorm could be used for forecasting of space weather disturbed conditions

Static and Dynamic Magnetism in Underdoped Superconductor BaFe1.92_{1.92}Co0.08_{0.08}As2_2

We report neutron scattering measurements on single crystals of BaFe$_{1.92}$Co$_{0.08}$As$_2$. The magnetic Bragg peak intensity is reduced by 6 % upon cooling through T$_C$. The spin dynamics exhibit a gap of 8 meV with anisotropic three-dimensional (3d) interactions. Below T$_C$ additional intensity appears at an energy of $\sim$4.5(0.5) meV similar to previous observations of a spin resonance in other Fe-based superconductors. No further gapping of the spin excitations is observed below T$_C$ for energies down to 2 meV. These observations suggest the redistribution of spectral weight from the magnetic Bragg position to a spin resonance demonstrating the direct competition between static magnetic order and superconductivity.Comment: 4 pages, 4 figure