Here we provide a self-consistent analytical solution describing the unsteady flow in the slender thin film which is expelled radially outwards when a drop hits a dry solid wall. Thanks to the fact ...that the fluxes of mass and momentum entering into the toroidal rim bordering the expanding liquid sheet are calculated analytically, we show here that our theoretical results closely follow the measured time-varying position of the rim with independence of the wetting properties of the substrate. The particularization of the equations describing the rim dynamics at the instant the drop reaches its maximal extension which, in analogy with the case of Savart sheets, is characterized by a value of the local Weber number equal to one, provides an algebraic equation for the maximum spreading radius also in excellent agreement with experiments. The self-consistent theory presented here, which does not make use of energetic arguments to predict the maximum spreading diameter of impacting drops, provides us with the time evolution of the thickness and of the velocity of the rim bordering the expanding sheet. This information is crucial in the calculation of the diameters and of the velocities of the droplets ejected radially outwards for drop impact velocities above the splashing threshold.
A drop of radius
$R$
of a liquid of density
$\unicodeSTIX{x1D70C}$
, viscosity
$\unicodeSTIX{x1D707}$
and interfacial tension coefficient
$\unicodeSTIX{x1D70E}$
impacting a superhydrophobic substrate ...at a velocity
$V$
keeps its integrity and spreads over the solid for
$V<V_{c}$
or splashes, disintegrating into tiny droplets violently ejected radially outwards for
$V\geqslant V_{c}$
, with
$V_{c}$
the critical velocity for splashing. In contrast with the case of drop impact onto a partially wetting substrate, Riboux & Gordillo (Phys. Rev. Lett., vol. 113, 2014, 024507), our experiments reveal that the critical condition for the splashing of water droplets impacting a superhydrophobic substrate at normal atmospheric conditions is characterized by a value of the critical Weber number,
$We_{c}=\unicodeSTIX{x1D70C}\,V_{c}^{2}\,R/\unicodeSTIX{x1D70E}\sim O(100)$
, which hardly depends on the Ohnesorge number
$Oh=\unicodeSTIX{x1D707}/\sqrt{\unicodeSTIX{x1D70C}\,R\,\unicodeSTIX{x1D70E}}$
and is noticeably smaller than the corresponding value for the case of partially wetting substrates. Here we present a self-consistent model, in very good agreement with experiments, capable of predicting
$We_{c}$
as well as the full dynamics of the drop expansion and disintegration for
$We\geqslant We_{c}$
. In particular, our model is able to accurately predict the time evolution of the position of the rim bordering the expanding lamella for
$We\gtrsim 20$
as well as the diameters and velocities of the small and fast droplets ejected when
$We\geqslant We_{c}$
.
Here we present a method for producing noncoalescing monodisperse microbubbles in an efficient, massive and controlled way. Since our prototype is easily scalable, it can be straightforwardly adapted ...to satisfy the specific gas injection demands required by the different applications where it can be used, like bioreactors or water treatment or purification plants. The main feature of the bubbling device described here consists of injecting the gas at the leading edge of a wing in relative motion with respect to a liquid. The reasons for this particular design relies on the smallness of the drag coefficient of streamlined bodies and also on the fact that the strongest favorable pressure gradients and the minimum values of the liquid pressures are located at the leading edge of the airfoils composing the wing.
Main Recommendations
The following recommendations for post-polypectomy colonoscopic surveillance apply to all patients who had one or more polyps that were completely removed during a high quality ...baseline colonoscopy.
1
ESGE recommends that patients with complete removal of 1 – 4 < 10 mm adenomas with low grade dysplasia, irrespective of villous components, or any serrated polyp < 10 mm without dysplasia, do not require endoscopic surveillance and should be returned to screening.
Strong recommendation, moderate quality evidence.
If organized screening is not available, repetition of colonoscopy 10 years after the index procedure is recommended. Strong recommendation, moderate quality evidence.
2
ESGE recommends surveillance colonoscopy after 3 years for patients with complete removal of at least 1 adenoma ≥ 10 mm or with high grade dysplasia, or ≥ 5 adenomas, or any serrated polyp ≥ 10 mm or with dysplasia.
Strong recommendation, moderate quality evidence.
3
ESGE recommends a 3 – 6-month early repeat colonoscopy following piecemeal endoscopic resection of polyps ≥ 20 mm.
Strong recommendation, moderate quality evidence.
A first surveillance colonoscopy 12 months after the repeat colonoscopy is recommended to detect late recurrence.
Strong recommendation, high quality evidence.
4
If no polyps requiring surveillance are detected at the first surveillance colonoscopy, ESGE suggests to perform a second surveillance colonoscopy after 5 years.
Weak recommendation, low quality evidence.
After that, if no polyps requiring surveillance are detected, patients can be returned to screening.
5
ESGE suggests that, if polyps requiring surveillance are detected at first or subsequent surveillance examinations, surveillance colonoscopy may be performed at 3 years.
Weak recommendation, low quality evidence.
A flowchart showing the recommended surveillance intervals is provided (Fig. 1).
Small rookeries are rarely evaluated for marine turtles worldwide. Two species of sea turtles (Hawksbill, Eretmochelys imbricata; Leatherback, Dermochelys coriacea) nest on five main beaches of the ...northeast coast of the Paria Gulf in Venezuela. Population trends using generalized linear models at this rookery were assessed and compared with other small rookeries. Both species showed significant negative nesting trends: Nesting by critically endangered hawksbills decreased over nine seasons 2009–2017 (64–142 nests per year, General Linear Model Slope Value = −0.061; data pooled for five beaches); similarly, vulnerable leatherback nests decreased across the same period in the main beach Los Garzos (0–69 nests/year; GLMSV = −0.34). Besides human and natural predation of the nests, no significant environmental impacts affect the beaches except probably on Obispo Isthmus where a gas pipeline installation interrupted the nesting activity in 2014. Observed changes to the nesting trends in these small rookeries have a collective impact on broader conservation concerns for sea turtles in the region.
Background & Aims: Norfloxacin is highly effective in preventing spontaneous bacterial peritonitis recurrence in cirrhosis, but its role in the primary prevention of this complication is uncertain. ...Methods: Patients with cirrhosis and low protein ascitic levels (<15 g/L) with advanced liver failure (Child–Pugh score ≥ 9 points with serum bilirubin level ≥ 3 mg/dL) or impaired renal function (serum creatinine level ≥ 1.2 mg/dL, blood urea nitrogen level ≥ 25 mg/dL, or serum sodium level ≤ 130 mEq/L) were included in a randomized controlled trial aimed at comparing norfloxacin (35 patients) vs placebo (33 patients) in the primary prophylaxis of spontaneous bacterial peritonitis. The main end points of the trial were 3-month and 1-year probability of survival. Secondary end points were 1-year probability of development of spontaneous bacterial peritonitis and hepatorenal syndrome. Results: Norfloxacin administration reduced the 1-year probability of developing spontaneous bacterial peritonitis (7% vs 61%, P < .001) and hepatorenal syndrome (28% vs 41%, P = .02), and improved the 3-month (94% vs 62%, P = .003) and the 1-year (60% vs 48%, P = .05) probability of survival compared with placebo. Conclusions: Primary prophylaxis with norfloxacin has a great impact in the clinical course of patients with advanced cirrhosis. It reduces the incidence of spontaneous bacterial peritonitis, delays the development of hepatorenal syndrome, and improves survival.
Here we report the production of monodisperse microbubbles by taking advantage of the large values of both the pressure gradients and of the local velocities existing at the leading edge of airfoils ...in relative motion with a liquid. It is shown here that the scaling laws for the bubbling frequencies and the bubble diameters are identical to those found in microfluidics. Therefore, the metre-sized geometry presented here is a feasible candidate to circumvent the inherent problems of using micron-sized geometries in real applications – namely, wettability, the low productivity and the clogging of the microchannels by particles or other impurities.
ObjectivesAs mobile phone ownership becomes more widespread in low-income and middle-income countries, mobile phone surveys (MPSs) present an opportunity to collect data on health more ...cost-effectively. However, selectivity and coverage biases in MPS are concerns, and there is limited information about the population-level representativeness of these surveys compared with household surveys. This study aims at comparing the sociodemographic characteristics of the respondents of an MPS on non-communicable disease risk factors to a household survey in Colombia.DesignCross-sectional study. We used a random digit dialling method to select the samples for calling mobile phone numbers. The survey was conducted using two modalities: computer-assisted telephone interviews (CATIs) and interactive voice response (IVR). The participants were assigned randomly to one of the survey modalities based on a targeted sampling quota stratified by age and sex. The Quality-of-Life Survey (ECV), a nationally representative survey conducted in the same year of the MPS, was used as a reference to compare the sample distributions by sociodemographic characteristics of the MPS data. Univariate and bivariate analyses were performed to evaluate the population representativeness between the ECV and the MPSs.SettingThe study was conducted in Colombia in 2021.ParticipantsPopulation at least 18 years old with a mobile phone.ResultsWe completed 1926 and 2983 interviews for CATI and IVR, respectively. We found that the MPS data have a similar (within 10% points) age–sex data distribution compared with the ECV dataset for some subpopulations, mainly for young populations, people with none/primary and secondary education levels, and people who live in urban and rural areas.ConclusionsThis study shows that MPS could collect similar data to household surveys in terms of age, sex, high school education level and geographical area for some population categories. Strategies are needed to improve representativeness of the under-represented groups.
AIM： To compare the cleansing quality of polyethylene glycol electrolyte solution and sodium phosphate with different schedules of administration, and to evaluate whether the timing of the ...administration of bowel preparation affects the detection of polyps.
METHODS： One hundred and seventy-seven consecutive outpatients scheduled for colonoscopy were randomized in one of four groups to receive polyethylene glycol electrolyte solution or oral sodium phosphate with two different timing schedules. Quality of cleansing, polyp detection, and tolerance were evaluated.
RESULTS： Patients receiving polyethylene glycol or sodium phosphate on the same day as the colonoscopy, obtained good to excellent global cleansing scores more frequently than patients who received polyethylene glycol or sodium phosphate on the day prior to the procedure （P 〈 0.001）. Flat lesions, but not fiat adenomas, were more frequent in patients prepared on the same day （P = 0.02）.
CONCLUSION： The quality of colonic cleansing and the detection of fiat lesions are significantly improved when the preparation is taken on the day of the colonoscopy.
La producción de arroz comercial es indispensable para garantizar la seguridad alimentaria de la población, ya que el 93 % de los panameños consume, en promedio, 158 g de arroz blanco por día, lo que ...define al arroz como el producto base de la alimentación en Panamá. En 2004, Panamá pierde la autosuficiencia en arroz y, según el análisis de los años posteriores (2004-2016), no existe evidencia de una reacción a través de una política coherente para recuperarla. Este trabajo describe el sector arrocero de 1999 al 2016, con el objetivo de conocer las limitantes para reaccionar mediante una política sectorial.
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