Bremsstrahlung in alpha-Decay Reexamined

A high-statistics measurement of bremsstrahlung emitted in the alpha decay of 210Po has been performed, which allows to follow the photon spectra up to energies of ~ 500 keV. The measured differential emission probability is in good agreement with our theoretical results obtained within the quasi classical approximation as well as with the exact quantum mechanical calculation. It is shown that due to the small effective electric dipole charge of the radiating system a significant interference between the electric dipole and quadrupole contributions occurs, which is altering substantially the angular correlation between the alpha particle and the emitted photon.Comment: 10 pages, 5 figures, v2: fix of small typo

A Search for the Most Massive Galaxies. III. Global and Central Structure

We used the Advanced Camera for Surveys on board the Hubble Space Telescope to obtain high resolution i-band images of the centers of 23 single galaxies, which were selected because they have SDSS velocity dispersions larger than 350 km/s. The surface brightness profiles of the most luminous of these objects (M_i<-24) have well-resolved `cores' on scales of 150-1000 pc, and share similar properties to BCGs. The total luminosity of the galaxy is a better predictor of the core size than is the velocity dispersion. The correlations of luminosity and velocity dispersion with core size agree with those seen in previous studies of galaxy cores. Because of high velocity dispersions, our sample of galaxies can be expected to harbor the most massive black holes, and thus have large cores with large amounts of mass ejection. The mass-deficits inferred from core-Sersic fits to the surface-brightness profiles are approximately double the black-hole masses inferred from the M_bh-sigma relation and the same as those inferred from the M_bh-L relation. The less luminous galaxies (M_i>-23) tend to have steeper `power-law' inner profiles, higher-ellipticity, diskier isophotes, and bulge-to-total ratios of order 0.5 -- all of which suggest that they are `fast-rotators' and rotational motions could have contaminated the velocity dispersion estimate. There are obvious dust features within about 300 pc of the center in about 35% of the sample, predominantly in power-law rather than core galaxies.Comment: 27 Pages, 22 Figures, 2 Tables, Accepted for Publication in MNRA

Thermal and Evolved Gas Analysis of Calcite Under Reduced Operating Pressures: Implications for the 2011 MSL Sample Analysis at Mars (SAM) Instrument

The Mars Science Laboratory (MSL) is scheduled for launch in 2011. The science objectives for MSL are to assess the past or present biological potential, to characterize the geology, and to investigate other planetary processes that influence habitability at the landing site. The Sample Analysis at Mars (SAM) is a key instrument on the MSL payload that will explore the potential habitability at the landing site [1]. In addition to searching for organic compounds, SAM will have the capability to characterized evolved gases as a function of increasing temperature and provide information on the mineralogy of volatile-bearing phases such as carbonates, sulfates, phyllosilicates, and Fe-oxyhydroxides. The operating conditions in SAM ovens will be maintained at 30 mb pressure with a He carrier gas flowing at 1 sccm. We have previously characterized the thermal and evolved gas behaviors of volatile-bearing species under reduced pressure conditions that simulated operating conditions of the Thermal and Evolved Gas Analyzer (TEGA) that was onboard the 2007 Mars Phoenix Scout Mission [e.g., 2-8]. TEGA ovens operated at 12 mb pressure with a N2 carrier gas flowing at 0.04 sccm. Another key difference between SAM and TEGA is that TEGA was able to perform differential scanning calorimetry whereas SAM only has a pyrolysis oven. The operating conditions for TEGA and SAM have several key parameter differences including operating pressure (12 vs 30 mb), carrier gas (N2 vs. He), and carrier gas flow rate (0.04 vs 1 sccm). The objectives of this study are to characterize the thermal and evolved gas analysis of calcite under SAM operating conditions and then compare it to calcite thermal and evolved gas analysis under TEGA operating conditions

Meeting USDHHS Physical Activity Guidelines and Health Outcomes

International Journal of Exercise Science 10(1): 121-127, 2017 Current public health physical activity (PA) guidelines suggest ≥500 METmin/week of PA, with additional benefits beyond 1000 METmin/week (i.e., a dose response). Revised U.S. PA guidelines are scheduled for 2018. The purpose was to relate health markers (blood pressure, percent fat, BMI, blood glucose, cholesterol, and cardiorespiratory fitness) to verify the dose response for PA guidelines revision. 505 non-smoking participants self-reported PA behaviors and completed medical screening. MANCOVA controlling for age and gender determined the relation between health markers and PA. MANCOVA indicated significantly (P\u3c.001) different health markers of percent fat, BMI, glucose, and treadmill time as a function of PA. Post-hoc Helmert contrasts (1] \u3c500 METmin/week vs. ≥500 METmin/week and 2] 500 to \u3c1000 METmin/week vs. ≥1000 METmin/week) indicated that meeting the PA guidelines was associated with better health markers and higher cardiorespiratory fitness. Effect sizes were greater for contrast 1 than for contrast 2, suggesting a plateauing effect. Revised public health guidelines should consider achievement of ≥500 METmin/week to be most important, with additional modest gain thereafter. Revised PA guidelines should stress the importance of achieving 500-1000 METmin/week

Diffraction microtomography with sample rotation: influence of a missing apple core in the recorded frequency space

Diffraction microtomography in coherent light is foreseen as a promising technique to image transparent living samples in three dimensions without staining. Contrary to conventional microscopy with incoherent light, which gives morphological information only, diffraction microtomography makes it possible to obtain the complex optical refractive index of the observed sample by mapping a three-dimensional support in the spatial frequency domain. The technique can be implemented in two configurations, namely, by varying the sample illumination with a fixed sample or by rotating the sample using a fixed illumination. In the literature, only the former method was described in detail. In this report, we precisely derive the three-dimensional frequency support that can be mapped by the sample rotation configuration. We found that, within the first-order Born approximation, the volume of the frequency domain that can be mapped exhibits a missing part, the shape of which resembles that of an apple core. The projection of the diffracted waves in the frequency space onto the set of sphere caps covered by the sample rotation does not allow for a complete mapping of the frequency along the axis of rotation due to the finite radius of the sphere caps. We present simulations of the effects of this missing information on the reconstruction of ideal objects.Comment: 7 pages, 11 figures, presented at Focus On Microscopy 200

The QUEST large area CCD camera

We have designed, constructed, and put into operation a very large area CCD camera that covers the field of view of the 1.2 m Samuel Oschin Schmidt Telescope at the Palomar Observatory. The camera consists of 112 CCDs arranged in a mosaic of four rows with 28 CCDs each. The CCDs are 600 x 2400 pixel Sarnoff thinned, back-illuminated devices with 13 µm x 13 µm pixels. The camera covers an area of 4.6° x 3.6° on the sky with an active area of 9.6 deg_2. This camera has been installed at the prime focus of the telescope and commissioned, and scientific-quality observations on the Palomar-QUEST Variability Sky Survey were started in 2003 September. The design considerations, construction features, and performance parameters of this camera are described in this paper