6,225 research outputs found
New light on Galactic post-asymptotic giant branch stars. I. First distance catalogue
We have commenced a detailed analysis of the known sample of Galactic
post-asymptotic giant branch (PAGB) objects compiled in the Toru\'n catalogue
of Szczerba et al., and present, for the first time, homogeneously derived
distance determinations for the 209 likely and 87 possible catalogued PAGB
stars from that compilation. Knowing distances are essential in determining
meaningful physical characteristics for these sources and this has been
difficult to determine for most objects previously. The distances were
determined by modelling their spectral energy distributions (SED) with multiple
black-body curves, and integrating under the overall fit to determine the total
distance-dependent flux. This method works because the luminosity of these
central stars is very nearly constant from the tip of the AGB phase to the
beginning of the white-dwarf cooling track. This then enables us to use a
standard-candle luminosity to estimate the SED distances. For Galactic thin
disk PAGB objects, we use three luminosity bins based on typical observational
characteristics, ranging between 3500 and 12000 L_sun. We further adopt a
default luminosity of 1700 L_sun for all halo PAGB objects. We have also
applied the above technique to a further sample of 69 related nebulae not in
the current edition of the Toru\'n catalogue. In a follow-up paper we will
estimate distances to the subset of RV Tauri variables using empirical
period-luminosity relations, and to the R\,CrB stars, allowing a population
comparison of these objects with the other subclasses of PAGB stars for the
first time.Comment: 24 pages, 8 tables, 4 figures. Submitted to MNRAS. Appendix B
containing full list of SED figures excluded in this versio
Evaluating Common Measures 2.0 in 4-H: Intra- and Interpersonal Skills Predict Engaged Citizenship
Research indicates that positive youth development (PYD) programming leads to improved developmental outcomes. Yet there continues to be a lack of clarity about how PYD programs are defined and measured. Therefore, Common Measures 2.0 was created for assessing 4-H youth development programs. We examined the universal skills (intrapersonal and interpersonal) and engaged citizenship scales of Common Measures 2.0 through a survey of 175 participants at a 4-H youth leadership conference. Intrapersonal and interpersonal skills were significantly positively associated with engaged citizenship. The universal skills and engaged citizenship scales showed acceptable factor loadings and Cronbach\u27s alpha values. Limitations and future directions are discussed
High prevalence of cardiovascular risk factors and insulin resistance 6 years after hyperglycemia first detected in pregnancy in Cape Town, South Africa
Objective To investigate the prevalence and associated cardiovascular risk factors 6 years after hyperglycemia first detected in pregnancy (HFDP) in Cape Town, South Africa. Research design and methods Data were collected during the index pregnancy from all women diagnosed with HFDP at a major referral hospital in Cape Town. Participants were evaluated 6 years later using a cross-sectional study. At follow-up participants had a 75 g oral glucose tolerance test, fasting lipogram, blood pressure and anthropometric measurements, and a fieldworker administered the questionnaire. We used the Adult Treatment Panel III criteria for the diagnosis of metabolic syndrome and individual risk factors. Insulin resistance was assessed using the homeostatic model of insulin resistance. Results At follow-up 220 women were reviewed. Their mean age at follow-up was 37.2 (SD 6.0) years. The prevalence of cardiovascular disease (CVD) risk factors was 60.9% (95% CI 54.3 to 67.2) for metabolic syndrome, 75% (95% CI 65.9 to 82.3) for insulin resistance, 62.3% (95% CI 55.6 to 68.5) for dysglycemia, 41.4% (95% CI 35.0 to 48.0) for raised blood pressure, and 74.6% (95% CI 683 to 79.9) for dyslipidemia. Women with diabetes in pregnancy compared with those with gestational diabetes during the index pregnancy had a higher prevalence of metabolic syndrome (74.3% vs 54.7%, p=0.010) and dysglycemia (88.6% vs 50.0%, p<0.001) at follow-up. Lower school education attainment, having a subsequent pregnancy, waist circumference at follow-up, and fasting blood glucose at HFDP diagnosis were associated with metabolic syndrome. Conclusion We found a high prevalence of CVD risk factors in South African women within 6 years of HFDP, which highlights the need to develop and evaluate interventions optimizing the cardiometabolic health of this vulnerable group. The main limitations of our research are the lack of a comparative group of women without HFDP and that we did not assess for CVD risk factors before HFDP. - Author(s) (or their employer(s)) 2019. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.Funding This research was funded by the Chronic Disease Initiative for Africa. We acknowledge funding from the International Development Research Centre (IDRC) (fund number: 411592) for TC (under the IINDIAGO project).Scopu
Giant Molecular Clouds are More Concentrated to Spiral Arms than Smaller Clouds
From our catalog of Milky Way molecular clouds, created using a temperature
thresholding algorithm on the Bell Laboratories 13CO Survey, we have extracted
two subsets:(1) Giant Molecular Clouds (GMCs), clouds that are definitely
larger than 10^5 solar masses, even if they are at their `near distance', and
(2) clouds that are definitely smaller than 10^5 solar masses, even if they are
at their `far distance'. The positions and velocities of these clouds are
compared to the loci of spiral arms in (l, v) space. The velocity separation of
each cloud from the nearest spiral arm is introduced as a `concentration
statistic'. Almost all of the GMCs are found near spiral arms. The density of
smaller clouds is enhanced near spiral arms, but some clouds (~10%) are
unassociated with any spiral arm. The median velocity separation between a GMC
and the nearest spiral arm is 3.4+-0.6 km/s, whereas the median separation
between smaller clouds and the nearest spiral arm is 5.5+-0.2 km/s.Comment: 11 pages, 3 figure
Hollow bunch distributions at high intensity in the PS booster
Bunches from the CERN PS Booster (PSB) with an improved bunching factor due to a hollow longitudinal distribution would facilitate the production of a high-intensity (>7´1012/bunch) proton beam needed for the future neutron time-of-flight facility. It would also provide a safety margin for the Large Hadron Collider beam, where a double-batch transfer is used in which the first PSB batch waits for 1.2 seconds at 1.4 GeV in the PS for the second one to arrive. Since the earlier reports of the successful acceleration of low-intensity hollow bunches in the PSB, theoretical studies of the Beam Transfer Function (BTF) have led to a greatly improved understanding of the stability requirements of such beams. In addition, an experimental study of the capture of hollow coasting beams has revealed that structure resulting from the linac acceleration process persists for a remarkably long time. Any inhomogeneity has to be smeared out and the degree of hollowness carefully adjusted by a controlled longitudinal blow-up before a reproducible, stable bunch can be created. A method has been developed for reliably creating hollow distributions of up to 8´1012 protons per bunch which have been routinely accelerated in the PSB
A prototype ASIC for APD array readout of scintillating plastic fibers
We report on the development of custom front-end electronics for use with avalanche photodiode (APD) arrays as part of a NASA technology study for the readout of scintillating plastic fibers. APD arrays featuring 64 1 mm square pixels are used. We demonstrate that a pixel of these APD arrays coupled to relatively thin (0.25 mm) and short (15 cm) scintillating plastic fibers can be used to detect and measure the tracks of even minimum ionizing particles (MIPs). An applicationspecific integrated circuit (ASIC) implementation of the electronics is required to produce a detector sufficiently compact for practical use in a flight experiment featuring many thousands of channels. This paper briefly describes the detector concept and performance and presents the design and performance of a four-channel prototype ASIC fabricated using the 0.35 micron TSMC process
Pengaruh Senam Poco-poco Terhadap Kadar Kolesterol Low Density Lipoprotein Darah
: High level of plasma LDL-cholesterol concentrations is one of the cause of atherosclerosis that may result in cardiovascular diseases (CVD), such as coronary heart disease (CHD) and stroke. Exercise can improve plasma LDL-cholesterol concentrations. A type of exercise, poco-poco, is categorized to the aerobic gymnastics. This study aimed to know the influence of poco-poco to plasma LDL-cholesterol concentrations. This was an experimental study with one group prestest-posttest design. Samples were 25 female students of 2013 batch Pharmacy study program of Sam Ratulangi University Manado that were chosen with purposive sampling. Samples did poco-poco gymnasticss three times a week for four consecutive weeks. The results showed that after four weeks of poco-poco there was an increase of the average of plasma LDL-cholesterol concentrations for 1.120 mg/dl, but this increase was not statistically significant (p > 0.05). Conclusion: There was no significant influence of doing poco-poco for four weeks to plasma LDL-cholesterol concentrations
First Interferometric Observations of Molecular Gas in a Polar Ring: The Helix Galaxy NGC 2685
We have detected four Giant Molecular cloud Associations (GMAs) (sizes <
6.6'' ~ 430 pc) in the western and eastern region of the polar ring in NGC2685
(the Helix galaxy) using the Owens Valley Radio Observatory (OVRO) millimeter
interferometer. Emission from molecular gas is found close to the brightest
Halpha and HI peaks in the polar ring and is confirmed by new IRAM 30m single
dish observations. The CO and HI line velocities are very similar, providing
additional kinematic confirmation that the CO emission emerges from the polar
ring. For the first time, the total molecular mass within a polar ring is
determined (M_H2~(8-11)x10^6 M_sol, using the standard Galactic conversion
factor). We detect about M_H2~4.4x10^6 M_sol in the nuclear region with the
single dish. Our upper limit derived from the interferometric data is lower
(M_H2<0.7x10^6 M_sol) suggesting that the molecular gas is distributed in an
extended (< 1.3 kpc) diffuse disk. These new values are an order of magnitude
lower than in previous reports. The total amount of molecular gas and the
atomic gas content of the polar ring are consistent with formation due to
accretion of a small gas-rich object, such as a dwarf irregular. The properties
of the NGC2685 system suggest that the polar ring and the host galaxy have been
in a stable configuration for a considerable time (few Gyr). The second (outer)
HI ring within the disk of NGC2685 is very likely at the outer Lindblad
resonance (OLR) of the ~ 11 kpc long stellar bar.Comment: 8 pages, 4 figures, accepted by ApJ Letter
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