Predictions of sediment trap biases in turbulent flows: A theoretical analysis based on observations from the literature

The physical variables affecting the trapping of particles in sediment collectors are grouped into a set of six dimensionless parameters, as a function of a dimensionless particle collection efficiency. Relevant laboratory calibration studies on sediment trap biases are evaluated to determine the quantitative dependence between collection efficiency and three of the parameters, trap Reynolds number, the ratio of flow speed to particle fall velocity and the ratio of trap height to mouth diameter, as well as trap geometry. We find that few of the parameters have been systematically tested in the laboratory and that trap Reynolds number-similarity for field conditions is maintained only for the slowest flow speeds and/or smallest trap diameters. However, the literature results do suggest some intriguing trends in biased trapping which also can be explained physically. The physical mechanisms are derived from a physical description of particle trapping based on observations of flow through traps, the mass balance for particles entering and leaving traps and a definition of particle collection efficiency, coupled with model development for cases where collection efficiency, as specified by the mass balance, deviates from one.The following testable hypotheses for biased trapping by unbaffied, straight-sided cylinders and noncylindrical traps result from our analysis. For fixed values of the other two parameters, collection efficiency of cylinders will decrease over some range of increasing trap Reynolds number, decrease over some range of decreasing particle fall velocity and increase over some range of increasing trap aspect ratio. Traps will be undercollectors or overcollectors depending on the physical mechanisms causing the biased collections. Predicting biased collections for noncylindrical traps is more complex but, in most cases, small-mouth, wide-body traps will be overcollectors and funnel-type traps will be undercollectors. Future laboratory studies are required to test these hypotheses and, in particular, parameter combinations representative of field conditions, where traps are deployed, must be tested

Validation of a skinfold based index for tracking proportional changes in lean mass

BACKGROUND: The lean mass index (LMI) is a new empirical measure that tracks within‐subject proportional changes in body mass adjusted for changes in skinfold thickness. OBJECTIVE: To compare the ability of the LMI and other skinfold derived measures of lean mass to monitor changes in lean mass. METHODS: 20 elite rugby union players undertook full anthropometric profiles on two occasions 10 weeks apart to calculate the LMI and five skinfold based measures of lean mass. Hydrodensitometry, deuterium dilution, and dual energy x ray absorptiometry provided a criterion choice, four compartment (4C) measure of lean mass for validation purposes. Regression based measures of validity, derived for within‐subject proportional changes through log transformation, included correlation coefficients and standard errors of the estimate. RESULTS: The correlation between change scores for the LMI and 4C lean mass was moderate (0.37, 90% confidence interval −0.01 to 0.66) and similar to the correlations for the other practical measures of lean mass (range 0.26 to 0.42). Standard errors of the estimate for the practical measures were in the range of 2.8–2.9%. The LMI correctly identified the direction of change in 4C lean mass for 14 of the 20 athletes, compared with 11 to 13 for the other practical measures of lean mass. CONCLUSIONS: The LMI is probably as good as other skinfold based measures for tracking lean mass and is theoretically more appropriate. Given the impracticality of the 4C criterion measure for routine field use, the LMI may offer a convenient alternative for monitoring physique changes, provided its utility is established under various conditions

Physicians\u27 ability to predict hospital length of stay for patients admitted to the hospital from the emergency department.

Accurate predictions of patient length of stay (LOS) in the hospital can effectively manage hospital resources and increase efficiency of patient care. A study was done to assess emergency medicine physicians\u27 ability of predicting the LOS of patients who enter the hospital through the ER. Results indicate that EM physicians are relatively accurate with their pediatric patients than any other age groups. In addition, as actual hospital LOS increases, the prediction accuracy decreases. Possible reasons may be due increasing medical complications associated with increasing age and this may lead to overall longer stays. Other variables such as the admitted service of the patient are not statistically significant in predicting LOS in this study. Future studies should be done in order to determine other variables that may affect LOS predictions

Physicians' Ability to Predict Hospital Length of Stay for Patients Admitted to the Hospital from the Emergency Department

Accurate predictions of patient length of stay (LOS) in the hospital can effectively manage hospital resources and increase efficiency of patient care. A study was done to assess emergency medicine physicians' ability of predicting the LOS of patients who enter the hospital through the ER. Results indicate that EM physicians are relatively accurate with their pediatric patients than any other age groups. In addition, as actual hospital LOS increases, the prediction accuracy decreases. Possible reasons may be due increasing medical complications associated with increasing age and this may lead to overall longer stays. Other variables such as the admitted service of the patient are not statistically significant in predicting LOS in this study. Future studies should be done in order to determine other variables that may affect LOS predictions

Incidental Findings on CT Scans in the Emergency Department

Objectives. Incidental findings on computed tomography (CT) scans are common. We sought to examine rates of findings and disclosure among discharged patients who received a CT scan in the ED. Methods. Retrospective chart review (Aug-Oct 2009) of 600 patients age 18 and older discharged home from an urban Level 1 trauma center. CT reports were used to identify incidental findings and discharge paperwork was used to determine whether the patient was informed of these findings. Results. There were 682 CT scans among 600 patients: 199 Abdomen & Pelvis, 405 Head, and 78 Thorax. A total of 348 incidental findings were documented in 228/682 (33.4%) of the scans, of which 34 (9.8%) were reported to patients in discharge paperwork. Patients with 1 incidental finding were less likely to receive disclosure than patients with 2 or more (P = .010). Patients age <60 were less likely to have incidental findings (P < .001). There was no significant disclosure or incidental finding difference by gender. Conclusions. While previous research suggests that CT incidental findings are often benign, reporting to patients is recommended but this is rarely happening

Understanding the remarkable difference in liquid crystal behaviour between secondary and tertiary amides : the synthesis and characterisation of new benzanilide-based liquid crystal dimers

Open Access via the RSC Open Access AgreementPeer reviewedPublisher PD

Measuring the effects of fractionated radiation therapy in a 3D prostate cancer model system using SERS nanosensors.

Multicellular tumour spheroids (MTS) are three-dimensional cell cultures that possess their own microenvironments and provide a more meaningful model of tumour biology than monolayer cultures. As a result, MTS are becoming increasingly used as tumor models when measuring the efficiency of therapies. Monitoring the viability of live MTS is complicated by their 3D nature and conventional approaches such as fluorescence often require fixation and sectioning. In this paper we detail the use of Surface Enhanced Raman Spectroscopy (SERS) to measure the viability of MTS grown from prostate cancer (PC3) cells. Our results show that we can monitor loss of viability by measuring pH and redox potential in MTS and furthermore we demonstrate that SERS can be used to measure the effects of fractionation of a dose of radiotherapy in a way that has potential to inform treatment planning.EaStCHEM, NHS Lothian, Jamie King Cancer Research FundThis is the final version of the article. It first appeared from the Royal Society of Chemistry via http://dx.doi.org/10.1039/C6AN01032