Angular dependence of domain wall resistivity in SrRuO3_{{\bf 3}} films

${\rm SrRuO_3}$ is a 4d itinerant ferromagnet (T$_{c}$ $\sim$150 K) with stripe domain structure. Using high-quality thin films of SrRuO$_{3}$ we study the resistivity induced by its very narrow ($\sim 3$ nm) Bloch domain walls, $\rho_{DW}$ (DWR), at temperatures between 2 K and T$_{c}$ as a function of the angle, $\theta$, between the electric current and the ferromagnetic domains walls. We find that $\rho_{DW}(T,\theta)=\sin^2\theta \rho_{DW}(T,90)+B(\theta)\rho_{DW}(T,0)$ which provides the first experimental indication that the angular dependence of spin accumulation contribution to DWR is $\sin^2\theta$. We expect magnetic multilayers to exhibit a similar behavior.Comment: 5 pages, 5 figure

Black String Entropy and Fourier-Mukai Transform

We propose a microscopic description of black strings in F-theory based on string duality and Fourier-Mukai transform. These strings admit several different microscopic descriptions involving D-brane as well as M2 or M5-brane configurations on elliptically fibered Calabi-Yau threefolds. In particular our results can also be interpreted as an asymptotic microstate count for D6-D2-D0 configurations in the limit of large D2-charge on the elliptic fiber. The leading behavior of the microstate degeneracy in this limit is shown to agree with the macroscopic entropy formula derived from the black string supergravity solution.Comment: 22 pages, latex; v2: substantial revision of the macroscopic description of the system; results essentially unchange

The Cholecystectomy As A Day Case (CAAD) Score: A Validated Score of Preoperative Predictors of Successful Day-Case Cholecystectomy Using the CholeS Data Set

Background Day-case surgery is associated with significant patient and cost benefits. However, only 43% of cholecystectomy patients are discharged home the same day. One hypothesis is day-case cholecystectomy rates, defined as patients discharged the same day as their operation, may be improved by better assessment of patients using standard preoperative variables. Methods Data were extracted from a prospectively collected data set of cholecystectomy patients from 166 UK and Irish hospitals (CholeS). Cholecystectomies performed as elective procedures were divided into main (75%) and validation (25%) data sets. Preoperative predictors were identified, and a risk score of failed day case was devised using multivariate logistic regression. Receiver operating curve analysis was used to validate the score in the validation data set. Results Of the 7426 elective cholecystectomies performed, 49% of these were discharged home the same day. Same-day discharge following cholecystectomy was less likely with older patients (OR 0.18, 95% CI 0.15–0.23), higher ASA scores (OR 0.19, 95% CI 0.15–0.23), complicated cholelithiasis (OR 0.38, 95% CI 0.31 to 0.48), male gender (OR 0.66, 95% CI 0.58–0.74), previous acute gallstone-related admissions (OR 0.54, 95% CI 0.48–0.60) and preoperative endoscopic intervention (OR 0.40, 95% CI 0.34–0.47). The CAAD score was developed using these variables. When applied to the validation subgroup, a CAAD score of ≤5 was associated with 80.8% successful day-case cholecystectomy compared with 19.2% associated with a CAAD score >5 (p < 0.001). Conclusions The CAAD score which utilises data readily available from clinic letters and electronic sources can predict same-day discharges following cholecystectomy

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Corrugated Plastic Drain Tubing Used as Underground Conduit

Model studies were made to investigate the effect of high water velocity on the extent of soil movement when corrugated plastic drain tubing is used as conduits for underground terrace outlets on steep slopes. No significant amount of sediment was drawn into the tubing, even when the slope was 10 percent and velocity approached 9 ft per sec. The magnitude of the flow from the tubing to the soil was low in cohesive soils. But, with less cohesive soils this outflow was greater and there was considerable movement of soil from around the tubing. Corrugated plastic drain tubing has been used extensively in water disposal systems in recent years. Thus, there is a need for research to determine its performance and limitations. This study was undertaken to evaluate the effect of velocity of flow on the performance of such tubing when it is used as a conduit in underground terrace outlet systems. A successful method of controlling surface runoff combines a system of terraces and underground outlets to remove the excess water. The basic concept of such a system is to store the runoff temporarily in the terrace chan-nel and gradually drain it off through an underground conduit. Because of the detention storage, small diameter conduits can be used to carry the runoff. The underground terrace outlet system consists of a vertical intake riser located in the terrace channel, an underground conduit and an outlet section. Clay or concrete farm drain tile, clay sewer pipe, asbestos cement pipe or corrugated plastic tubing is used for the outlet conduit. In areas where excess groundwater is a problem, it is desirable that the system provides subsurface drainage in addition to removal of surface runoff. When drain tile is used, groundwater enters the drain at the joint between the tiles. When the velocity in the tile line becomes excessive on steep slopes, the turbulence causes movement of soil near the opening between the tiles, which re-sults in misalignment of the tile line. When misalignment occurs, the flow is obstructed and the turbulence increases which, in turn, causes greater misalignment and causes debris to enter the line. Design recommendations by ASAE (1974) to prevent the misalignment, include maximum permissible velocities in tile drains when protective measures are not used. The velocities range from 3.5 to 9.0 ft per sec depending on soil texture. On sites where the grade exceeds 2.0 percent or the design velocities exceed the given value, special protective measures are recommended. For continuous pipe with perforations, the recom-mended protective measure is to com-pletely enclose the pipe with filter mate-rials. In most occasions an underground conduit used as a terrace outlet must be installed on much steeper slope than 2.0 percent and the water velocity in the conduit becomes quite high. Misalignment is not a problem with corrugated plastic drain tubing since the tubing is flexible and continuous. Nevertheless, in some areas the velocity limitations specified for drain tile are also used for corrugated plastic drain tubing (Griessel and Beasley 1969). No research has been cited to show the validity of these velocity limitations as applied to the corrugated plastic drain tubing. Corrugated plastic drain tubing has a number of perforations per foot of length. Therefore, it is possible that some water escapes to the soil from the tubing. This outflow may establish a flow along the sides and beneath the tubing. The flow may cause movement of soil along the sides of the tubing or undermining the tubing.This article is published as Misra, M. K., and R. P. Beasley. "Corrugated Plastic Drain Tubing Used as Underground Conduit." Transactions of the ASAE 18, no. 2 (1975): 0260-0262. DOI: 10.13031/2013.36568. Copyright 1975 ASABE. Posted with permission