Assessment of friction from compression ring conjunction of a high performance internal combustion engine: a combined numerical and experimental study

The paper presents direct measurement of in-cylinder friction from a single cylinder motocross race engine under motored conditions and compares the same with a new analytical predictive method. These conditions are encountered in piston-cylinder system with the application of cylinder deactivation (CDA) technology, which is a growing trend. The analytical method takes into account the various regions within instantaneous contact of compression ring-cylinder liner, including lubricant film rupture, cavitation zone and the subsequent lubricant film reformation. The analysis also includes the effect of boundary friction and lubricant rheology. The predictions and direct measurements of cyclic friction show good agreement and indicate dominance of viscous friction under the investigated engine running conditions. In particular, it is shown that the compression ring contribution to in-cycle friction is most pronounced in the region of high cylinder pressures because of combined Poiseuille friction and some boundary solid interactions. The combined experimental-analytical approach has not hitherto been reported in literatur

Diagnosis and management of postpartum hemorrhage and intrapartum asphyxia in a quality improvement initiative using nurse-mentoring and simulation in Bihar, India.

BackgroundIn the state of Bihar, India a multi-faceted quality improvement nurse-mentoring program was implemented to improve provider skills in normal and complicated deliveries. The objective of this analysis was to examine changes in diagnosis and management of postpartum hemorrhage (PPH) of the mother and intrapartum asphyxia of the infant in primary care facilities in Bihar, during the program.MethodsDuring the program, mentor pairs visited each facility for one week, covering four facilities over a four-week period and returned for subsequent week-long visits once every month for seven to nine consecutive months. Between- and within-facility comparisons were made using a quasi-experimental and a longitudinal design over time, respectively, to measure change due to the intervention. The proportions of PPH and intrapartum asphyxia among all births as well as the proportions of PPH and intrapartum asphyxia cases that were effectively managed were examined. Zero-inflated negative binomial models and marginal structural methodology were used to assess change in diagnosis and management of complications after accounting for clustering of deliveries within facilities as well as time varying confounding.ResultsThis analysis included 55,938 deliveries from 320 facilities. About 2% of all deliveries, were complicated with PPH and 3% with intrapartum asphyxia. Between-facility comparisons across phases demonstrated diagnosis was always higher in the final week of intervention (PPH: 2.5-5.4%, intrapartum asphyxia: 4.2-5.6%) relative to the first week (PPH: 1.2-2.1%, intrapartum asphyxia: 0.7-3.3%). Within-facility comparisons showed PPH diagnosis increased from week 1 through 5 (from 1.6% to 4.4%), after which it decreased through week 7 (3.1%). A similar trend was observed for intrapartum asphyxia. For both outcomes, the proportion of diagnosed cases where selected evidence-based practices were used for management either remained stable or increased over time.ConclusionsThe nurse-mentoring program appears to have built providers' capacity to identify PPH and intrapartum asphyxia cases but diagnosis levels are still not on par with levels observed in Southeast Asia and globally

Modeling the initiation of others into injection drug use, using data from 2,500 injectors surveyed in Scotland during 2008-2009

The prevalence of injection drug use has been of especial interest for assessment of the impact of blood-borne viruses. However, the incidence of injection drug use has been underresearched. Our 2-fold aim in this study was to estimate 1) how many other persons, per annum, an injection drug user (IDU) has the equivalent of full responsibility (EFR) for initiating into injection drug use and 2) the consequences for IDUs' replacement rate. EFR initiation rates are strongly associated with incarceration history, so that our analysis of IDUs' replacement rate must incorporate when, in their injecting career, IDUs were first incarcerated. To do so, we have first to estimate piecewise constant incarceration rates in conjunction with EFR initiation rates, which are then combined with rates of cessation from injecting to model IDUs' replacement rate over their injecting career, analogous to the reproduction number of an epidemic model. We apply our approach to Scotland's IDUs, using over 2,500 anonymous injector participants who were interviewed in Scotland's Needle Exchange Surveillance Initiative during 2008-2009. Our approach was made possible by the inclusion of key questions about initiations. Finally, we extend our model to include an immediate quit rate, as a reasoned compensation for higher-than-expected replacement rates, and we estimate how high initiates' quit rate should be for IDUs' replacement rate to be 1

Reasoning About Vote Counting Schemes Using Light-weight and Heavy-weight Methods

We compare and contrast our experiences in specifying, implementing and verifying the monotonicity property of a simple plurality voting scheme using modern light-weight and heavy-weight verification tools

Laser-assisted cataract surgery versus standard ultrasound phacoemulsification cataract surgery.

BACKGROUND: Cataract is the leading cause of blindness in the world, and cataract surgery is one of the most commonly performed operations in the Western world. Preferred surgical techniques have changed dramatically over the past half century with associated improvements in outcomes and safety. Femtosecond laser platforms that can accurately and reproducibly perform key steps in cataract surgery, including corneal incisions, capsulotomy and lens fragmentation, are now available. The potential advantages of laser-assisted surgery are broad, and include greater safety and better visual outcomes through greater precision and reproducibility. OBJECTIVES: To compare the effectiveness of laser-assisted cataract surgery with standard ultrasound phacoemulsification cataract surgery by gathering evidence on safety from randomised controlled trials (RCTs). SEARCH METHODS: We searched CENTRAL (which contains the Cochrane Eyes and Vision Trials Register) (2016, Issue 4), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to May 2016), EMBASE (January 1980 to May 2016), Latin American and Caribbean Health Sciences Literature Database (LILACS) (January 1982 to May 2016), the ISRCTN registry (www.isrctn.com/editAdvancedSearch), ClinicalTrials.gov (www.clinicaltrials.gov), the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en) and the U.S. Food and Drugs Administration (FDA) website (www.fda.gov). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 10 May 2016. SELECTION CRITERIA: We included randomised controlled trials where laser-assisted cataract surgery was compared to standard ultrasound phacoemulsification cataract surgery. We graded the certainty of the evidence using GRADE. DATA COLLECTION AND ANALYSIS: Two review authors independently screened the search results, assessed risk of bias and extracted data using the standard methodological procedures expected by Cochrane. The primary outcome for this review was intraoperative complications in the operated eye, namely anterior capsule and posterior capsule tears. The secondary outcomes were visual acuity (corrected distance visual acuity (CDVA) and uncorrected distance visual acuity (UDVA)), refractive outcomes, quality of vision (as measured by any validated visual function score), postoperative complications and cost-effectiveness. MAIN RESULTS: We included 16 RCTs conducted in Germary, Hungary, Italy, India, China and Brazil that enrolled a total of 1638 eyes of 1245 adult participants. Overall, the studies were at unclear or high risk of bias. In 11 of the studies the authors reported financial links with the manufacturer of the laser platform evaluated in their studies. Five of the studies were within-person (paired-eye) studies with one eye allocated to one procedure and the other eye allocated to the other procedure. These studies were reported ignoring the paired nature of the data.The number of anterior capsule and posterior capsule tears reported in the included studies for both laser cataract surgery and manual phacoemulsification cataract surgery were low. There were four anterior capsule tears and one posterior capsule tear in 1076 eyes reported in 10 studies (2 anterior capsule tears in laser arms, 2 anterior capsule tears and 1 posterior capsule tear in standard phacoemulsification arms). We are very uncertain as to the effect of laser-assisted surgery compared to standard phacoemulsification surgery with respect to these two outcomes. For postoperative cystoid macular oedema and elevated postoperative intraocular pressures, again the evidence was inconclusive (odds ratio (OR) 0.58, 95% confidence interval (CI) 0.20 to 1.68; 957 eyes, 9 studies, low certainty evidence; and OR 0.57, 95% CI 0.11 to 2.86; 903 eyes, 8 studies, low certainty evidence).We found little evidence of any important difference in postoperative visual acuity between laser-assisted and standard phacoemulsification arms. There was a small advantage for laser-assisted cataract surgery at six months in CDVA. However, the mean difference (MD) was -0.03 logMAR (95% CI -0.05 to -0.00; 224 eyes, 3 studies, low certainty evidence) which is equivalent to 1.5 logMAR letters and is therefore, clinically insignificant. No studies reported patient-reported outcome measures such as visual function.There were no data reported on costs or resource use but three studies reported the time taken to do the surgery. There was little evidence of any major difference between the two procedures in this respect (MD 0.1 minutes, 95% CI -0.02 to 0.21; 274 eyes, low certainty evidence). AUTHORS' CONCLUSIONS: The evidence from the 16 randomised controlled trials RCTs included in this review could not determine the equivalence or superiority of laser-assisted cataract surgery compared to standard manual phacoemulsification for our chosen outcomes due to the low to very low certainty of the evidence available from these studies. As complications occur rarely, large, adequately powered, well designed, independent RCTs comparing the safety and efficacy of laser-assisted cataract surgery with standard phacoemulsification cataract surgery are needed. Standardised reporting of complications and visual and refractive outcomes for cataract surgery would facilitate future synthesis. Data on patient-reported outcomes and cost-effectiveness are needed. Paired-eye studies should be analysed and reported appropriately

Individual Characteristics That Promote or Prevent Psychological Safety and Error Reporting in Healthcare: A Systematic Review.

BACKGROUND: Healthcare errors continue to be a safety issue and an economic burden that causes death, increased length of stays, and emotional trauma to families and the person who commits the error.  Speaking up and error reporting within a safety culture can reduce the incidence of error; however, this is complex and multifaceted. AIM: This systematic review investigates individual characteristics that support or prevent speaking up behaviors when adverse events occur.  This study further explores how organizational interventions designed to promote error reporting correlate to individual characteristics and perceptions of psychological safety.  . METHODS: A systematic review of peer-reviewed articles in healthcare that contain characteristics of an individual that promote or prevent error reporting was conducted. The search yielded 1233 articles published from 2015 to 2021. From this set, 81 full-text articles were assessed for eligibility and ultimately extracted data from 28 articles evaluated for quality using Joanna Briggs Institute critical appraisal tools©. PRINCIPAL FINDINGS: The primary themes for individual character traits, values, and beliefs that influence a person\u27s decision to speak up/report an error include self-confidence and positive perceptions of self, the organization, and leadership. Education, experience and knowledge are sub themes that relate to confidence. The primary individual characteristics that serve as barriers are 1) self-preservation associated with fear and 2) negative perceptions of self, the organization, and leadership. CONCLUSION: The results show that an individual\u27s perception of their environment, whether or not it is psychologically safe, may be impacted by personal perceptions that stem from deep-seated personal values. This exposes a crucial need to explore cultural and diversity aspects of healthcare error reporting and how to individualize interventions to reduce fear and promote error reporting