Measurements in merging flow

Previous measurements of the velocity field in the vicinity of two intersecting submerged turbulent jets provided evidence that, contrary to the usual assumptions, intersecting flows may not necessarily be combined using vector addition of velocities or momentum flux densities. To gather additional experimental evidence on the details of the velocity field near the intersection of two submerged turbulent jets, this study measured time average velocity magnitudes and directions of two perpendicular intersecting axisymmetric submerged turbulent incompressible air jets of approximately equal strength. Because of the need to detect reverse flows, a three-dimensional pitot-type probe was used. This could sense yaw and pitch angles as well as velocity magnitudes. Two sets of measurements were taken. The more detailed set was confined to the plane of the nozzles, the less detailed set obtained cross-sectional data at four stations, three of these being in the observed reverse flow. The data show that the reverse flow spreads much more rapidly perpendicular to the nozzle plane than in the nozzle plane, whereas the forward flow is fairly symmetric. , Similarity profiles were found in both the forward and reverse flows. In the forward flow the distribution was essentially Gaussian. This was also true in the backward flow in the direction normal to the plane of the nozzles. In the plane of the nozzles the backward flow profiles were close to semi-elliptical or semi-circular, depending on the scales for plotting.U.S. Department of the InteriorU.S. Geological SurveyOpe

Experimental studies of wing-wall mixing control

Detailed velocity traverses are presented for shallow submerged slot jets without lateral confinement. With wing-walls in place maximum velocities and temperatures were traced for both unheated and heated discharges. These tests were repeated for various wing-wall crest elevations and wing-wall lengths. For the wing-wall tests a typical Reynolds number based on slot width was 400,000 and a typical densimetric Froude number based on slot width was 40. Some flow combinations were found to be unstable and tests were conducted to delineate the limits of stability. The tests demonstrate that flow patterns may be controlled using controlled flow over wing-wall crests. A simple design procedure making use of the data is illustrated.U.S. Department of the InteriorU.S. Geological SurveyOpe

Methodology for synthesis and optimization of diffusion patterns in flow systems

This analytic study used a generalization of Reichardt's hypothesis by Alexander, Baron & Comings to develop a unified treatment for the synthesis of diffusion patterns for mass, heat and momentum. The technique was applied for co-planar and co-axial flows, to a study of the effects of initial flux distribution and outlet shape on diffusion patterns; and to shallow submerged outlets. Four simple approximations to the P-function, involving only exponential and error functions, were found to represent flux distributions downstream from a circular jet of finite size at all points between the nozzle and infinity. The results may be applied in the study and design of discharge outlets, syphon spillways, hydraulic breakwaters and diffusion of tracers in streams and penstocks.U.S. Department of the InteriorU.S. Geological SurveyOpe

Buoyant surface jets discharged into a strong crossflow

Analytical and experimental investigations were carried out for three-dimensional buoyant surface jets with strong ambient flow but without boundary attachment. A numerical model in curvilinear coordinates was developed from an integral jet analysis modified for buoyancy effects and included asymmetry of the jet. Detailed temperature distributions were measured in the laboratory with densimetric Froude numbers (F̥) of 5, 10 and 15 and 0 velocity ratios (R) from 2 to 13. Experimental results showed that ambient crossflows can cause significant distortion of the jet, even for R = 13. Near the exit, the lower portion of the jet is swept toward the lee side of the jet. The resulting L-shaped cross section and the associated density instability may enhance spreading on the lee side and may contribute to the subsequent formation of bimodal temperature distributions. The jet bending increases as R decreases and as F̥ increases. Dilution increases with increasing F̥ and decreasing R. The model was calibrated against the entire set of measured temperatures for each run and is capable of predicting temperature 0 distributions to an accuracy of 0.63C˚. The agreement could probably be improved by using similarity profiles better suited to the actual jet cross sectional shape which was not known at the beginning of the research.U.S. Department of the InteriorU.S. Geological SurveyOpe

Study of stratified overflows and underflows

The study presents a general analysis of two-layered stratified flows taking into account effects of sidewall friction and variation of density with horizontal distance. The analysis is applied to the study of arrested thermal wedges and arrested cold water intrusions. Laboratory data were collected and analyzed and it was determined that bed roughness has a significant effect on the interfacial friction factor for arrested thermal wedges but not for arrested cold water intrusions. Friction factors were found to vary significantly along the wedges indicating that use of average values is perhaps undesirable. Local values of friction factor were found to increase with values of a local interfacial Reynolds number.U.S. Department of the InteriorU.S. Geological SurveyOpe

Evaluation of Daily Low-Dose Prednisolone During Upper Respiratory Tract Infection to Prevent Relapse in Children With Relapsing Steroid-Sensitive Nephrotic Syndrome: The PREDNOS 2 Randomized Clinical Trial

Importance: In children with corticosteroid-sensitive nephrotic syndrome, many relapses are triggered by upper respiratory tract infections. Four small studies found that administration of daily low-dose prednisolone for 5 to 7 days at the time of an upper respiratory tract infection reduced the risk of relapse, but the generalizability of their findings is limited by location of the studies and selection of study population. / Objective: To investigate the use of daily low-dose prednisolone for the treatment of upper respiratory tract infection-related relapses. / Design, Setting, and Participants: This double-blind, placebo-controlled randomized clinical trial (Prednisolone in Nephrotic Syndrome [PREDNOS] 2) evaluated 365 children with relapsing steroid-sensitive nephrotic syndrome with and without background immunosuppressive treatment at 122 pediatric departments in the UK from February 1, 2013, to January 31, 2020. Data from the modified intention-to-treat population were analyzed from July 1, 2020, to December 31, 2020. / Interventions: At the start of an upper respiratory tract infection, children received 6 days of prednisolone, 15 mg/m2 daily, or matching placebo preparation. Those already taking alternate-day prednisolone rounded their daily dose using trial medication to the equivalent of 15 mg/m2 daily or their alternate-day dose, whichever was greater. / Main Outcomes and Measures: The primary outcome was the incidence of first upper respiratory tract infection-related relapse. Secondary outcomes included overall rate of relapse, changes in background immunosuppressive treatment, cumulative dose of prednisolone, rates of serious adverse events, incidence of corticosteroid adverse effects, and quality of life. / Results: The modified intention-to-treat analysis population comprised 271 children (mean [SD] age, 7.6 [3.5] years; 174 [64.2%] male), with 134 in the prednisolone arm and 137 in the placebo arm. The number of patients experiencing an upper respiratory tract infection-related relapse was 56 of 131 (42.7%) in the prednisolone arm and 58 of 131 (44.3%) in the placebo arm (adjusted risk difference, -0.02; 95% CI, -0.14 to 0.10; P = .70). No evidence was found that the treatment effect differed according to background immunosuppressive treatment. No significant differences were found in secondary outcomes between the treatment arms. A post hoc subgroup analysis assessing the primary outcome in 54 children of South Asian ethnicity (risk ratio, 0.66; 95% CI, 0.40-1.10) vs 208 children of other ethnicity (risk ratio, 1.11; 95% CI, 0.81-1.54) found no difference in efficacy of intervention in those of South Asian ethnicity (test for interaction P = .09). / Conclusions and Relevance: The results of PREDNOS 2 suggest that administering 6 days of daily low-dose prednisolone at the time of an upper respiratory tract infection does not reduce the risk of relapse of nephrotic syndrome in children in the UK. Further work is needed to investigate interethnic differences in treatment response. / Trial Registration: isrctn.org / Identifier: ISRCTN10900733; EudraCT 2012-003476-39

The Sloan Digital Sky Survey Reverberation Mapping Project: Key Results

We present the final data from the Sloan Digital Sky Survey Reverberation Mapping (SDSS-RM) project, a precursor to the SDSS-V Black Hole Mapper Reverberation Mapping program. This data set includes 11-year photometric and 7-year spectroscopic light curves for 849 broad-line quasars over a redshift range of 0.1<z<4.5 and a luminosity range of Lbol=1E44-47.5 erg/s, along with spectral and variability measurements. We report 23, 81, 125, and 110 reverberation mapping lags (relative to optical continuum variability) for broad Halpha, Hbeta, MgII and CIV using the SDSS-RM sample, spanning much of the luminosity and redshift ranges of the sample. Using 30 low-redshift RM AGNs with dynamical-modeling black hole masses, we derive a new estimate of the average virial factor of =0.62+-0.07 for the line dispersion measured from the RMS spectrum. The intrinsic scatter of individual virial factors is 0.31+-0.07 dex, indicating a factor of two systematic uncertainty in RM black hole masses. Our lag measurements reveal significant R-L relations for Hbeta and MgII at high redshift, consistent with the latest measurements based on heterogeneous samples. While we are unable to robustly constrain the slope of the R-L relation for CIV given the limited dynamical range in luminosity, we found substantially larger scatter in CIV lags at fixed L1350. Using the SDSS-RM lag sample, we derive improved single-epoch (SE) mass recipes for Hbeta, MgII and CIV, which are consistent with their respective RM masses as well as between the SE recipes from two different lines, over the luminosity range probed by our sample. The new Hbeta and MgII recipes are approximately unbiased estimators at given RM masses, but there are systematic biases in the CIV recipe. The intrinsic scatter of SE masses around RM masses is ~0.45 dex for Hbeta and MgII, increasing to ~0.58 dex for CIV.Comment: 33 pages. Data products available at ftp://quasar.astro.illinois.edu/public/sdssrm/final_result

Early carboniferous brachiopod faunas from the Baoshan block, west Yunnan, southwest China

38 brachiopod species in 27 genera and subgenera are described from the Yudong Formation in the Shidian-Baoshan area, west Yunnan, southwest China. New taxa include two new subgenera: Unispirifer (Septimispirifer) and Brachythyrina (Longathyrina), and seven new species: Eomarginifera yunnanensis, Marginatia cylindrica, Unispirifer (Unispirifer) xiangshanensis, Unispirifer (Septimispirifer) wafangjieensis, Brachythyrina (Brachythyrina) transversa, Brachythyrina (Longathyrina) baoshanensis, and Girtyella wafangjieensis. Based on the described material and constraints from associated coral and conodont faunas, the age of the brachiopod fauna from the Yudon Formation is considered late Tournaisian (Early Carboniferous), with a possibility extending into earlyViseacutean.<br /

Relationship among fibre type, myosin ATPase activity and contractile properties

At least two types of skeletal muscle myosin have been described which differ in ATPase activity and stability in alkaline or acidic media. Differences in ATPase characteristics distinguish Type I and Type II fibres histochemically. In this study, ATPase activity of myosin from muscles of several species with known histochemical and contractile properties has been determined to test the hypothesis that (1) myosin ATPase activity, (2) histochemical determination of fibre types and (3) maximum shortening velocity, all provide equivalent estimates of contractile properties in muscles of mixed fibre types. Maximum shortening velocity appears to be proportional to ATPase activity as expected from previous reports by Barany. However, both myosin ATPase and the maximum shortening velocity exhibit curvilinear relationships to the fraction of cross-sectional area occupied by Type II fibres. Therefore, we reject the hypothesis and conclude that histochemically determined myofibrillar ATPase does not accurately reflect the intrinsic ATPase activity or shortening velocity in muscles of mixed fibre types. Our data are consistent with the presence of more than two myosin isozymes or with a mixture of isozymes within single muscle fibres.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42851/1/10735_2005_Article_BF01005238.pd