Boundary sources in the Doran - Lobo - Crawford spacetime

We take a null hypersurface (the causal horizon) generated by a congruence of null geodesics as the boundary of the Doran-Lobo-Crawford spacetime, to be the place where the Brown-York quasilocal energy is located. The components of the outer and inner stress tensors are computed and shown to depend on time and on the impact parameter $b$ of the test particle trajectory. The surface energy density $\sigma$ on the boundary is given by the same expression as that obtained previously for the energy stored on a Rindler horizon.Comment: 4 pages, title changed, no figures, minor text change

Meta-analysis of goal directed fluid therapy using transoesophageal doppler in patients undergoing elective colorectal surgery

Background: Intraoperative goal-directed fluid therapy (GDFT) is recommended for intraoperative fluid management for elective colorectal surgery in most perioperative guidelines. However, the evidence in elective colorectal surgery alone is not wellestablished.The aim of this meta-analysis was to compare the effects of GDFT with conventional fluid therapy on outcomes following elective colorectal surgery.Methods: A meta-analysis of randomised controlled trials examining the role of transoesophageal Doppler guided GDFT with conventional fluid therapy in adult patients undergoing elective colorectal surgery was performed in accordance with PRISMA methodology. The primary outcome measure was overall morbidity, with secondaryoutcome measures of hospital length of stay, time to return of gastrointestinal function, 30-day mortality, acute kidney injury, and surgical site infection and anastomotic leak rates.Results: A total of 11 studies were included with a total of 1113 patients; 556 who had undergone GDFT and 557 who had undergone conventional fluid therapy. There was no significant difference in any clinical outcome measure studied between GDFT and conventional fluid therapy, including overall morbidity (RR 0.90, 95% CI 0.75 to 1.08, p=0.27, I2=47%, n=991), 30-day mortality (RR 0.67, 95% CI 0.23 to 1.92, p=0.45, I2=0%, n=1039) and hospital length of stay (mean difference 0.01 days, 95% CI -0.92 to 0.94, p=0.98, I2=34%, n=1049).Conclusions: This meta-analysis does not support the perceived benefits of goal-directed fluid therapy guided by transoesophageal Doppler monitoring in the setting of elective colorectal surgery

Schwarzschild Solution on the Brane

In this communication we have shown that Schwarzschild solution is possible in brane world for some specific choices of brane matter and the non local effects from the bulk. A conformally flat bulk space time with fine-tuned vacuum energy (brane tension) shows that, Schwarzschild solution may also be the vacuum solution for brane world scenario.Comment: 3 page

The Reporting on ERAS Compliance, Outcomes, and Elements Research (RECOvER) Checklist: A Joint Statement by the ERAS^® and ERAS^® USA Societies.

Enhanced recovery after surgery (ERAS) programs are multimodal care pathways designed to minimize the physiological and psychological impact of surgery for patients. Increased compliance with ERAS guidelines is associated with improved patient outcomes across surgical types. As ERAS programs have proliferated, an unintentional effect has been significant variation in how ERAS-related studies are reported in the literature. To improve the quality of ERAS reporting, ERAS <sup>®</sup> USA and the ERAS <sup>®</sup> Society launched an effort to create an instrument to assist authors in manuscript preparation. Criteria to include were selected by a combination of literature review and expert opinion. The final checklist was refined by group consensus. The Societies present the Reporting on ERAS Compliance, Outcomes, and Elements Research (RECOvER) Checklist. The tool contains 20 items including best practices for reporting clinical pathways, compliance auditing, and formatting guidelines. The RECOvER Checklist is intended to provide a standardized framework for the reporting of ERAS-related studies. The checklist can also assist reviewers in evaluating the quality of ERAS-related manuscripts. Authors are encouraged to include the RECOvER Checklist when submitting ERAS-related studies to peer-reviewed journals

Consensus on Training and Implementation of Enhanced Recovery After Surgery: A Delphi Study.

Enhanced Recovery After Surgery (ERAS) is widely accepted in current surgical practice due to its positive impact on patient outcomes. The successful implementation of ERAS is challenging and compliance with protocols varies widely. Continual staff education is essential for successful ERAS programmes. Teaching modalities exist, but there remains no agreement regarding the optimal training curriculum or how its effectiveness is assessed. We aimed to draw consensus from an expert panel regarding the successful training and implementation of ERAS. A modified Delphi technique was used; three rounds of questionnaires were sent to 58 selected international experts from 11 countries across multiple ERAS specialities and multidisciplinary teams (MDT) between January 2016 and February 2017. We interrogated opinion regarding four topics: (1) the components of a training curriculum and the structure of training courses; (2) the optimal framework for successful implementation and audit of ERAS including a guide for data collection; (3) a framework to assess the effectiveness of training; (4) criteria to define ERAS training centres of excellence. An ERAS training course must cover the evidence-based principles of ERAS with team-oriented training. Successful implementation requires strong leadership, an ERAS facilitator and an effective MDT. Effectiveness of training can be measured by improved compliance. A training centre of excellence should show a willingness to teach and demonstrable team working. We propose an international expert consensus providing an ERAS training curriculum, a framework for successful implementation, methods for assessing effectiveness of training and a definition of ERAS training centres of excellence

Opioid prescription at postoperative discharge: a retrospective observational cohort study

Opioid misuse is now considered a major public health epidemic in North America, with substantial social and financial consequences. As well as socio-economic and commercial drivers, modifiable risk-factors that have resulted in this crisis have been identified. The purpose of this study was to identify whether, within England, modifiable drivers for persistent postoperative opioid use were present. This was a retrospective cohort study of practice at 14 National Health Service hospitals across England. Data were collected retrospectively and validated for adult patients undergoing elective intermediate and major or complex major general surgical procedures between 1 and 31 March 2019. Of the 509 patients enrolled from 14 centres, 499 were included in the data analysis. In total, 31.5% (157/499) patients were in the intermediate surgery cohort and 68.5% (342/499) were in the major or complex major surgery cohort, with 21.0% (33/157) and 21.6% (74/342) discharged with opioid medicines to be taken at regular intervals, respectively. There were similar median oral morphine equivalent doses prescribed at discharge. Of patients prescribed regular opioid medicines, 76.6% (82/107) had a specified duration at discharge. However, 72.9% (78/107) had no written deprescribing advice on discharge. Similarly, of patients prescribed ‘when required’ opioids, 59.6% (93/156) had a specified duration of their prescription and 33.3% (52/156) were given written deprescribing advice. This study has identified a pattern of poor prescribing practices, a lack of guidance and formal training at individual institutions and highlights opportunities for improvement in opioid-prescribing practices within England

Interior of a Schwarzschild black hole revisited

The Schwarzschild solution has played a fundamental conceptual role in general relativity, and beyond, for instance, regarding event horizons, spacetime singularities and aspects of quantum field theory in curved spacetimes. However, one still encounters the existence of misconceptions and a certain ambiguity inherent in the Schwarzschild solution in the literature. By taking into account the point of view of an observer in the interior of the event horizon, one verifies that new conceptual difficulties arise. In this work, besides providing a very brief pedagogical review, we further analyze the interior Schwarzschild black hole solution. Firstly, by deducing the interior metric by considering time-dependent metric coefficients, the interior region is analyzed without the prejudices inherited from the exterior geometry. We also pay close attention to several respective cosmological interpretations, and briefly address some of the difficulties associated to spacetime singularities. Secondly, we deduce the conserved quantities of null and timelike geodesics, and discuss several particular cases in some detail. Thirdly, we examine the Eddington-Finkelstein and Kruskal coordinates directly from the interior solution. In concluding, it is important to emphasize that the interior structure of realistic black holes has not been satisfactorily determined, and is still open to considerable debate.Comment: 15 pages, 7 figures, Revtex4. V2: Version to appear in Foundations of Physic

ESPEN guideline: Clinical nutrition in surgery.

Early oral feeding is the preferred mode of nutrition for surgical patients. Avoidance of any nutritional therapy bears the risk of underfeeding during the postoperative course after major surgery. Considering that malnutrition and underfeeding are risk factors for postoperative complications, early enteral feeding is especially relevant for any surgical patient at nutritional risk, especially for those undergoing upper gastrointestinal surgery. The focus of this guideline is to cover nutritional aspects of the Enhanced Recovery After Surgery (ERAS) concept and the special nutritional needs of patients undergoing major surgery, e.g. for cancer, and of those developing severe complications despite best perioperative care. From a metabolic and nutritional point of view, the key aspects of perioperative care include: • integration of nutrition into the overall management of the patient • avoidance of long periods of preoperative fasting • re-establishment of oral feeding as early as possible after surgery • start of nutritional therapy early, as soon as a nutritional risk becomes apparent • metabolic control e.g. of blood glucose • reduction of factors which exacerbate stress-related catabolism or impair gastrointestinal function • minimized time on paralytic agents for ventilator management in the postoperative period • early mobilisation to facilitate protein synthesis and muscle function The guideline presents 37 recommendations for clinical practice

Localization by disorder in the infrared conductivity of (Y,Pr)Ba2Cu3O7 films

The ab-plane reflectivity of (Y{1-x}Prx)Ba2Cu3O7 thin films was measured in the 30-30000 cm-1 range for samples with x = 0 (Tc = 90 K), x = 0.4 (Tc = 35 K) and x = 0.5 (Tc = 19 K) as a function of temperature in the normal state. The effective charge density obtained from the integrated spectral weight decreases with increasing x. The variation is consistent with the higher dc resistivity for x = 0.4, but is one order of magnitude smaller than what would be expected for x = 0.5. In the latter sample, the conductivity is dominated at all temperatures by a large localization peak. Its magnitude increases as the temperature decreases. We relate this peak to the dc resistivity enhancement. A simple localization-by-disorder model accounts for the optical conductivity of the x = 0.5 sample.Comment: 7 pages with (4) figures include

Wormhole Geometries In f(R,T)f(R,T) Gravity

We study wormhole solutions in the framework of f (R,T) gravity where R is the scalar curvature, and T is the trace of the stress-energy tensor of the matter. We have obtained the shape function of the wormhole by specifying an equation of state for the matter field and imposing the flaring out condition at the throat. We show that in this modified gravity scenario, the matter threading the wormhole may satisfy the energy conditions, so it is the effective stress-energy that is responsible for violation of the null energy condition.Comment: 9 pages, 4 figures, published version, references adde