2,870 research outputs found
Phytochemical study of endemic Costa Rican Annonaceae species Annona pittieri and Cymbopetalum costaricense
Phytochemical profile of the Central American rainforest endemic Annonaceae species, Annona pittieri and Cymbonopetallum costaricense, were studied in search
of novel bioactive compounds. The acetogenin squamocin (1) isolated from A. pittieri showed cytotoxic activity against human acute lymphocytic leukaemia with
low activity against healthy blood cells. In addition, other eight compounds were isolated from A. pittieri, including a novel 2-azaanthraquinone alkaloid,
4-methoxybenzo[g]isoquinoline-5,10-dione (2). Furthermore, from C. costaricense three compounds were isolated including a novel 1-azaanthraquinone alkaloid,
6-hydroxy-9-methoxy-cleistopholine (3)Universidad de Costa Rica/[809-B2-028]/UCR/Costa RicaUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigaciones en Productos Naturales (CIPRONA
Panchromatic radiative transfer modeling of stars and dust in the Sombrero galaxy
We present a detailed study of the dust energy balance in the Sombrero galaxy
M104. From a full radiative transfer analysis, including scattering, absorption
and thermal re-emission, we construct models that can reproduce images at
optical/near-infrared wavelengths, the observed stellar SED and the minor axis
extinction profiles in the V and R_C band. A standard model, that contains only
an old stellar population to heat the dust, underestimates the observations of
dust emission at infrared wavelengths by a factor of ~ 3. Supplementing this
basic model with a young stellar component of low star formation activity in
both the inner disk (SFR ~ 0.21 Msun/yr) and dust ring (SFR ~ 0.05 Msun/yr), we
are capable of solving the discrepancy in the dust energy budget of the
Sombrero galaxy at wavelengths shortwards of 100 \mum. To account for the
increased FIR/submm emission beyond 100 \mum, we propose a additional dust
component distributed in quiescent clumps. This model with a clumpy dust
structure predicts three-quarters of the total dust content (~ 2.8 x 10^7 Msun)
to reside in compact dust clouds with no associated embedded sources. Although
the assumption of a clumpy dust structure in the Sombrero galaxy is supported
by high-resolution optical data, we cannot rule out the possibility that dust
grains with a higher dust emissivity account for part of the discrepancy in the
energy budget at submm wavelengths.Comment: 10 pages, 5 figures, accepted for publication in MNRA
A cognitive-behavioural pedometer-based group intervention on physical activity and sedentary behaviour in individuals with type 2 diabetes
The purpose of this study was to investigate the benefits of a pedometer and a cognitive-behavioural group intervention for promoting physical activity (PA) in type 2 diabetes patients. We recruited 41 participants and randomized them into an intervention group (IG) (n = 20) and a control group (CG) (n = 21). The intervention consisted of five sessions within 12 weeks, a booster session after 22 weeks and a pedometer. Primary outcome was PA assessed by accelerometer (minutes per day) and pedometer (steps per day). Secondary outcomes were weight, body mass index, blood pressure, haemoglobin A1c and total cholesterol. After 12 weeks, the IG increased with more than 2000 steps day−1 compared with the CG, whereas sedentary behaviour decreased more than 1 hour day−1 in the IG and showed no change in the CG. There was no intervention effect on the accelerometer-based PA nor on health measurements. After 1 year, the increase in steps per day remained significant in the IG, but sedentary activity increased again to baseline levels. This pilot study showed that the combination of a 12-week cognitive-behavioura intervention and a pedometer has a significant short-term impact on daily steps and sedentary behaviour but that the effects on total PA and long-term effects were limited
Process theory and research: Exploring the dialectic tension
We contest that although the notion of process is increasingly being applied to the study of organizations, these attempts are hampered by significant methodological shortcomings. We claim that the value of process theory is under-utilized because most attempts to apply process theory end up reverting to conventional non-process methods. We suggest that the cause of this reversion is primarily the challenge of making sense, of fixing the world, propelling us from process into the world of substance. To break free of these limitations we propose an approach that takes the researchers? audience alongside the subject processes rather than attempting to clinically intersect them. We illuminate this paper with our own story vignettes concerning the fortunes of an idea that passes by the name of value based management (VBM). 1 These vignettes are meant to both exemplify and disrupt the theoretical narrative
Radio polarization and sub-mm observations of the Sombrero galaxy (NGC 4594) - Large-scale magnetic field configuration and dust emission
We observed the nearby early-type spiral galaxy NGC 4594 (M 104, Sombrero
galaxy) with the Very Large Array at 4.86 GHz, with the Effelsberg 100-m
telescope at 8.35 GHz as well as with the Heinrich Hertz Telescope at 345 GHz
in radio continuum. The 4.86 and 8.35 GHz data contain polarization information
and hence information about the magnetic fields: we detected a large-scale
magnetic field which is to our knowledge the first detection of a large-scale
magnetic field in an Sa galaxy in the radio range. The magnetic field
orientation in M104 is predominantly parallel to the disk but has also vertical
components at larger z-distances from the disk. This field configuration is
typical for normal edge-on spiral galaxies. The 345 GHz data pertain to the
cold dust content of the galaxy. Despite the optical appearance of the object
with the huge dust lane, its dust content is smaller than that of more
late-type spirals.Comment: 10 pages with 9 figures. Accepted for publication in A&
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Reply to: New Meta- and Mega-analyses of Magnetic Resonance Imaging Findings in Schizophrenia: Do They Really Increase Our Knowledge About the Nature of the Disease Process?
This work was supported by National Institute of Biomedical Imaging and Bioengineering Grant No. U54EB020403 (to the ENIGMA consortium)
Population prevalence of Chlamydia trachomatis and Neisseria gonorrhoeae in the Netherlands. should asymptomatic persons be tested during Population-based chlamydia Screening also for gonorrhoea or only if chlamydial infection is found?
BACKGROUND: Screening and active case finding for Chlamydia trachomatis (CT) is recommended to prevent reproductive morbidity. However insight in community prevalence of gonococcal infections and co-infections with Neisseria gonorrhoea (NG) is lacking. METHODS: Nested study within a large population-based Chlamydia Screening Pilot among 21.000 persons 15–29 year. All CT-positive (166) and a random sample of 605 CT-negative specimens were as well tested for gonococcal infection. RESULTS: Overall Chlamydia prevalence in the Pilot was 2.0% (95% CI: 1.7–2.3), highest in very urban settings (3.2%; 95% CI: 2.4–4.0) and dependent of several risk factors. Four gonococcal infections were found among 166 participants with CT infection (4/166 = 2.4%; 95% CI: 0.1%–4.7%). All four had several risk factors and reported symptoms. Among 605 CT-negative persons, no infection with NG could be confirmed. CONCLUSION: A low rate of co-infections and a very low community prevalence of gonococcal infections were found in this population based screening programme among young adults in the Netherlands. Population screening for asymptomatic gonococcal infections is not indicated in the Netherlands. Although co-infection with gonorrhoea among CT-positives is dependent on symptoms and well-known algorithms for elevated risks, we advise to test all CT-positives also for NG, whether symptomatic or asymptomatic
Performance of the CMS Cathode Strip Chambers with Cosmic Rays
The Cathode Strip Chambers (CSCs) constitute the primary muon tracking device
in the CMS endcaps. Their performance has been evaluated using data taken
during a cosmic ray run in fall 2008. Measured noise levels are low, with the
number of noisy channels well below 1%. Coordinate resolution was measured for
all types of chambers, and fall in the range 47 microns to 243 microns. The
efficiencies for local charged track triggers, for hit and for segments
reconstruction were measured, and are above 99%. The timing resolution per
layer is approximately 5 ns
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