981 research outputs found
Response to “Comment on ‘Seagrass Viviparous Propagules as a Potential Long-Distance Dispersal Mechanism’ by A. C. G. Thomson et al”
Bound states of 3He at the edge of a 4He drop on a cesium surface
We show that small amounts of 3He atoms, added to a 4He drop deposited on a
flat cesium surface at zero temperature, populate bound states localized at the
contact line. These edge states show up for drops large enough to develop well
defined surface and bulk regions together with a contact line, and they are
structurally different from the well-known Andreev states that appear at the
free surface and at the liquid-solid interface of films. We illustrate the
one-body density of 3He in a drop with 1000 4He atoms, and show that for
sufficiently large number of impurities, the density profiles spread beyond the
edge, coating both the curved drop surface and its flat base and eventually
isolating it from the substrate.Comment: 10 pages and 7 figures. Submitted to PR
Inspiratory muscle warm-up does not improve cycling time-trial performance
Purpose: This study examined the effects of an active cycling warm-up, with and without the addition of an inspiratory muscle warm-up (IMW), on 10-km cycling time-trial performance
From nonwetting to prewetting: the asymptotic behavior of 4He drops on alkali substrates
We investigate the spreading of 4He droplets on alkali surfaces at zero
temperature, within the frame of Finite Range Density Functional theory. The
equilibrium configurations of several 4He_N clusters and their asymptotic trend
with increasing particle number N, which can be traced to the wetting behavior
of the quantum fluid, are examined for nanoscopic droplets. We discuss the size
effects, inferring that the asymptotic properties of large droplets correspond
to those of the prewetting film
Thoracic load carriage-induced respiratory muscle fatigue.
We investigated the effect of carrying a 25 kg backpack upon exercise-induced respiratory muscle fatigue, pulmonary function and physiological and perceptual responses to exercise.N/
Tobacco and alcohol use among healthcare workers in three public hospitals in KwaZulu-Natal, South Africa
Background: Tobacco use is a risk factor for most of the leading causes of death in the world. Healthcare workers (HCWs) can play an important role in assisting patients to stop smoking, but this role is undermined if they themselves smoke. The study determined the prevalence of tobacco smoking and alcohol use among HCWs in public hospitals in KwaZulu-Natal, South Africa.Methods: In a cross-sectional study, 650 self-administered anonymous questionnaires (primary and secondary questionnaires) were administered to participants between December 2009 and June 2010. Six hundred and twenty primary questionnaires (on smoking) and 630 secondary questionnaires (on alcohol use) were returned, giving a response rate of 95% and 97% respectively. The Pearson chi-square test was used to test for statistical significance.Results: Eleven per cent of the participants were current smokers and 7.1% former smokers, while 27% of neversmokers were constantly exposed to second-hand smoke. Males were 13 times more likely to smoke than their female counterparts (P < 0.001). Never-smokers more frequently counselled their smoking patients to quit compared to former and current smokers (47.5%, 39.5% and 25.8% respectively). Alcohol use problems were reported by 22% of participants (P < 0.001). Current smokers were six times more likely to drink excessively than never-smokers (P < 0.001) and males were ten times more likely than females to drink excessively (P < 0.001).Conclusion: The smoking rate among HCWs is still high, although lower than the national average of 21.4%. A large number of participants reported exposure to second-hand smoke and alcohol use problems. Less than half of the HCWs counselled smoking patients to quit smoking.Keywords: health care worker, tobacco use, alcohol use, patient education for smoking cessatio
Improved Measurement of the Pseudoscalar Decay Constant
We present a new determination of the Ds decay constant, f_{Ds} using 5
million continuum charm events obtained with the CLEO II detector. Our value is
derived from our new measured ratio of widths for Ds -> mu nu/Ds -> phi pi of
0.173+/- 0.021 +/- 0.031. Taking the branching ratio for Ds -> phi pi as (3.6
+/- 0.9)% from the PDG, we extract f_{Ds} = (280 +/- 17 +/- 25 +/- 34){MeV}. We
compare this result with various model calculations.Comment: 23 page postscript file, postscript file also available through
http://w4.lns.cornell.edu/public/CLN
Search for the Decays B^0 -> D^{(*)+} D^{(*)-}
Using the CLEO-II data set we have searched for the Cabibbo-suppressed decays
B^0 -> D^{(*)+} D^{(*)-}. For the decay B^0 -> D^{*+} D^{*-}, we observe one
candidate signal event, with an expected background of 0.022 +/- 0.011 events.
This yield corresponds to a branching fraction of Br(B^0 -> D^{*+} D^{*-}) =
(5.3^{+7.1}_{-3.7}(stat) +/- 1.0(syst)) x 10^{-4} and an upper limit of Br(B^0
-> D^{*+} D^{*-}) D^{*\pm} D^\mp and
B^0 -> D^+ D^-, no significant excess of signal above the expected background
level is seen, and we calculate the 90% CL upper limits on the branching
fractions to be Br(B^0 -> D^{*\pm} D^\mp) D^+
D^-) < 1.2 x 10^{-3}.Comment: 12 page postscript file also available through
http://w4.lns.cornell.edu/public/CLNS, submitted to Physical Review Letter
Use of a colonoscope for distal duodenal stent placement in patients with malignant obstruction
Background: Stent placement in the distal duodenum or proximal jejunum with a therapeutic gastroscope can be difficult, because of the reach of the endoscope, loop formation in the stomach, and flexibility of the gastroscope. The use of a colonoscope may overcome these problems. Objective: To report our experience with distal duodenal stent placement in 16 patients using a colonoscope. Methods: Multicenter, retrospective series of patients with a malignant obstruction at the level of the distal duodenum and proximal jejunum and treated by stent placement using a colonoscope. Main outcome measurements are technical success, ability to eat, complications, and survival. Results: Stent placement was technically feasible in 93% (15/16) of patients. Food intake improved from a median gastric outlet obstruction scoring system (GOOSS) score of 1 (no oral intake) to 3 (soft solids) (p = 0.001). Severe complications were not observed. One patient had persistent obstructive symptoms presumably due to motility problems. Recurrent obstructive symptoms were caused by tissue/tumor ingrowth through the stent mesh [n = 6 (38%)] and stent occlusion by debris [n = 1 (6%)]. Reinterventions included additional stent placement [n = 5 (31%)], gastrojejunostomy [n = 2 (12%)], and endoscopic stent cleansing [n = 1 (6%)]. Median survival was 153 days. Conclusion: Duodenal stent placement can effectively and safely be performed using a colonoscope in patients with an obstruction at the level of the distal duodenum or proximal jejunum. A colonoscope has the advantage that it is long enough and offers good endoscopic stiffness, which avoids looping in the stomach
Vitamin D prevents endothelial progenitor cell dysfunction induced by sera from women with preeclampsia or conditioned media from hypoxic placenta
Context: Placenta-derived circulating factors contribute to the maternal endothelial dysfunction underlying preeclampsia. Endothelial colony forming cells (ECFC), a sub-population of endothelial progenitor cells (EPCs), are thought to be involved in vasculogenesis and endothelial repair. Low vitamin D concentrations are associated with an increased risk for preeclampsia. Objective: We hypothesized that the function of human fetal ECFCs in culture would be suppressed by exposure to preeclampsia-related factors-preeclampsia serum or hypoxic placental conditioned medium- in a fashion reversed by vitamin D. Design, Setting, Patients: ECFCs were isolated from cord blood of uncomplicated pregnancies and expanded in culture. Uncomplicated pregnancy villous placenta in explant culture were exposed to either 2% (hypoxic), 8% (normoxic) or 21% (hyperoxic) O2 for 48 h, after which the conditioned media (CM) was collected. Outcome Measures: ECFC tubule formation (Matrigel assay) and migration were examined in the presence of either maternal serum from preeclampsia cases or uncomplicated pregnancy controls, or pooled CM, in the presence or absence of 1,25(OH)2 vitamin D3. Results: 1,25(OH)2 vitamin D3 reversed the adverse effects of preeclampsia serum or CM from hypoxic placenta on ECFCs capillary-tube formation and migration. Silencing of VDR expression by VDR siRNA, VDR blockade, or VEGF pathway blockade reduced ECFC functional abilities. Effects of VDR or VEGF blockade were partially prevented by vitamin D. Conclusion: Vitamin D promotes the capillary-like tubule formation and migration of ECFCs in culture, minimizing the negative effects of exposure to preeclampsia-related factors. Further evaluation of the role of vitamin D in ECFC regulation and preeclampsia is warranted. © 2014 Brodowski et al
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