Aerodynamic characteristics of a large-scale semispan model with a swept wing and an augmented jet flap with hypermixing nozzles

The aerodynamic characteristics of the augmentor wing concept with hypermixing primary nozzles were investigated. A large-scale semispan model in the Ames 40- by 80-Foot Wind Tunnel and Static Test Facility was used. The trailing edge, augmentor flap system occupied 65% of the span and consisted of two fixed pivot flaps. The nozzle system consisted of hypermixing, lobe primary nozzles, and BLC slot nozzles at the forward inlet, both sides and ends of the throat, and at the aft flap. The entire wing leading edge was fitted with a 10% chord slat and a blowing slot. Outboard of the flap was a blown aileron. The model was tested statically and at forward speed. Primary parameters and their ranges included angle of attack from -12 to 32 degrees, flap angles of 20, 30, 45, 60 and 70 degrees, and deflection and diffuser area ratios from 1.16 to 2.22. Thrust coefficients ranged from 0 to 2.73, while nozzle pressure ratios varied from 1.0 to 2.34. Reynolds number per foot varied from 0 to 1.4 million. Analysis of the data indicated a maximum static, gross augmentation of 1.53 at a flap angle of 45 degrees. Analysis also indicated that the configuration was an efficient powered lift device and that the net thrust was comparable with augmentor wings of similar static performance. Performance at forward speed was best at a diffuser area ratio of 1.37

Large-scale V/STOL testing

Several facets of large-scale testing of V/STOL aircraft configurations are discussed with particular emphasis on test experience in the Ames 40- by 80-Foot Wind Tunnel. Examples of powered-lift test programs are presented in order to illustrate tradeoffs confronting the planner of V/STOL test programs. Large-scale V/STOL wind-tunnel testing can sometimes compete with small-scale testing in the effort required (overall test time) and program costs because of the possibility of conducting a number of different tests with a single large-scale model where several small-scale models would be required. The benefits of both high- or full-scale Reynolds numbers, more detailed configuration simulation, and number and type of onboard measurements are studied

Factors influencing the likelihood of instrumental delivery success.

OBJECTIVE: To evaluate risk factors for unsuccessful instrumental delivery when variability between individual obstetricians is taken into account. METHODS: We conducted a retrospective cohort study of attempted instrumental deliveries over a 5-year period (2008-2012 inclusive) in a tertiary United Kingdom center. To account for interobstetrician variability, we matched unsuccessful deliveries (case group) with successful deliveries (control group) by the same operators. Multivariate logistic regression was used to compare successful and unsuccessful instrumental deliveries. RESULTS: Three thousand seven hundred ninety-eight instrumental deliveries of vertex-presenting, single, term newborns were attempted, of which 246 were unsuccessful (6.5%). Increased birth weight (odds ratio [OR] 1.11; P<.001), second-stage labor duration (OR 1.01; P<.001), rotational delivery (OR 1.52; P<.05), and use of ventouse compared with forceps (OR 1.33; P<.05) were associated with unsuccessful outcome. When interobstetrician variability was controlled for, instrument selection and decision to rotate were no longer associated with instrumental delivery success. More senior obstetricians had higher rates of unsuccessful deliveries (12% compared with 5%; P<.05) but were used to undertake more complicated cases. Cesarean delivery during the second stage of labor without previous attempt at instrumental delivery was associated with higher birth weight (OR 1.07; P<.001), increased maternal age (OR 1.03; P<.01), and epidural analgesia (OR 1.46; P<.001). CONCLUSION: Results suggest that birth weight and head position are the most important factors in successful instrumental delivery, whereas the influence of instrument selection and rotational delivery appear to be operator-dependent. Risk factors for lack of instrumental delivery success are distinct from risk factors for requiring instrumental delivery, and these should not be conflated in clinical practice.This is the author accepted manuscript. The final version is published in Obstetrics & Gynecology 123: 796-803. doi: 10.1097/AOG.0000000000000188, which can be found here: http://journals.lww.com/greenjournal/Abstract/2014/04000/Factors_Influencing_the_Likelihood_of_Instrumental.11.asp

Direct contact and authoritarianism as moderators between extended contact and reduced prejudice: Lower threat and greater trust as mediators

Using a representative sample of Dutch adults (N = 1238), we investigated the moderating influence of direct contact and authoritarianism on the potential of extended contact to reduce prejudice. As expected, direct contact and authoritarianism moderated the effect of extended contact on prejudice. Moreover, the third-order moderation effect was also significant, revealing that extended contact has the strongest effect among high authoritarians with low levels of direct contact. We identified trust and perceived threat as the mediating processes underlying these moderation effects. The present study thus attests to the theoretical and practical relevance of reducing prejudice via extended contact. The discussion focuses on the role of extended contact in relation to direct contact and authoritarianism as well as on the importance of trust in intergroup contexts

The influence of hours worked prior to delivery on maternal and neonatal outcomes: a retrospective cohort study.

BACKGROUND: Long continuous periods of working contribute to fatigue, which is an established risk factor for adverse patient outcomes in many clinical specialties. The total number of hours worked by delivering clinicians before delivery therefore may be an important predictor of adverse maternal and neonatal outcomes. OBJECTIVE: We aimed to examine how rates of adverse delivery outcomes vary with the number of hours worked by the delivering clinician before delivery during both day and night shifts. STUDY DESIGN: We conducted a retrospective cohort study of 24,506 unscheduled deliveries at an obstetrics center in the United Kingdom from 2008-2013. We compared adverse outcomes between day shifts and night shifts using random-effects logistic regression to account for interoperator variability. Adverse outcomes were estimated blood loss of ≥1.5 L, arterial cord pH of ≤7.1, failed instrumental delivery, delayed neonatal respiration, severe perineal trauma, and any critical incident. Additive dynamic regression was used to examine the association between hours worked before delivery (up to 12 hours) and risk of adverse outcomes. Models were controlled for maternal age, maternal body mass index, parity, birthweight, gestation, obstetrician experience, and delivery type. RESULTS: We found no difference in the risk of any adverse outcome that was studied between day vs night shifts. Yet, risk of estimated blood loss of ≥1.5 L and arterial cord pH of ≤7.1 both varied by 30-40% within 12-hour shifts (P<.05). The highest risk of adverse outcomes occurred after 9-10 hours from the beginning of the shift for both day and night shifts. The risk of other adverse outcomes did not vary significantly by hours worked or by day vs night shift. CONCLUSION: Number of hours already worked before undertaking unscheduled deliveries significantly influences the risk of certain adverse outcomes. Our findings suggest that fatigue may play a role in increasing the risk of adverse delivery outcomes later in shifts and that obstetric work patterns could be better designed to minimize the risk of adverse delivery outcomes.ARA is supported by grant P2CHD047879, awarded to the Office of Population Research at Princeton University by The Eunice Kennedy Shriver National Institute of Child Health and Human Development of the National Institutes of Health. JGS is supported by a CAREER grant from the U.S. National Science Foundation (DMS-1255187).This is the author accepted manuscript. The final version is available from Elsevier via http://dx.doi.org/10.1016/j.ajog.2016.06.02

Weekend working: a retrospective cohort study of maternal and neonatal outcomes in a large NHS delivery unit.

OBJECTIVES: Mandatory weekend working for NHS consultants is currently the subject of intense political debate. The Secretary of State for Health's proposed 7-day contract policy is based on the claim that such working patterns will improve patient outcomes. We evaluate this claim by taking advantage of as-if-at-random presentation of women for non-elective deliveries throughout the week. We examine (i) whether consultants currently perform fewer deliveries during weekends versus weekdays, and (ii) whether adverse outcomes increase during weekends. STUDY DESIGN: We conducted a retrospective cohort study using data on all non-elective deliveries from January 2008 to December 2013 in a large UK obstetrics centre (n=27,466). We used Pearson's chi-squared tests to make direct comparisons of adverse outcome rates during weekdays versus weekends. Outcomes included: estimated maternal blood loss ≥1.5l; severe perineal trauma; delayed neonatal respiration; umbilical arterial pH <7.1; and critical incidents at delivery. RESULTS: Consultants currently perform the same proportion of non-elective deliveries on weekends and weekdays (2.3% versus 2.6%, p=0.25). We found no increase in any adverse maternal or neonatal outcomes during weekends versus weekdays, despite high statistical power to detect such differences. Moreover, adverse outcomes are no higher during periods of the weekend when consultants are not routinely present compared to equivalent periods during weekdays. CONCLUSIONS: Under current working arrangements, women who would benefit from consultant-led delivery are equally likely to receive one on weekends compared to weekdays. Weekend delivery has no effect on maternal or neonatal morbidity. Adopting mandatory 7-day contracts is unlikely to make any difference to either consultant-led delivery during weekends or to patient outcomes.The Eunice Kennedy Shriver National Institute of Child Health and Human Development of the National Institutes of Health (Grant ID: P2CHD047879)This is the author accepted manuscript. The final version is available from Elsevier via http://dx.doi.org/10.1016/j.ejogrb.2016.01.03

Management of fetal malposition in the second stage of labor: a propensity score analysis.

OBJECTIVE: We sought to determine the factors associated with selection of rotational instrumental vs cesarean delivery to manage persistent fetal malposition, and to assess differences in adverse neonatal and maternal outcomes following delivery by rotational instruments vs cesarean delivery. STUDY DESIGN: We conducted a retrospective cohort study over a 5-year period in a tertiary United Kingdom obstetrics center. In all, 868 women with vertex-presenting, single, liveborn infants at term with persistent malposition in the second stage of labor were included. Propensity score stratification was used to control for selection bias: the possibility that obstetricians may systematically select more difficult cases for cesarean delivery. Linear and logistic regression models were used to compare maternal and neonatal outcomes for delivery by rotational forceps or ventouse vs cesarean delivery, adjusting for propensity scores. RESULTS: Increased likelihood of rotational instrumental delivery was associated with lower maternal age (odds ratio [OR], 0.95; P < .01), lower body mass index (OR, 0.94; P < .001), lower birthweight (OR, 0.95; P < .01), no evidence of fetal compromise at the time of delivery (OR, 0.31; P < .001), delivery during the daytime (OR, 1.45; P < .05), and delivery by a more experienced obstetrician (OR, 7.21; P < .001). Following propensity score stratification, there was no difference by delivery method in the rates of delayed neonatal respiration, reported critical incidents, or low fetal arterial pH. Maternal blood loss was higher in the cesarean group (295.8 ± 48 mL, P < .001). CONCLUSION: Rotational instrumental delivery is often regarded as unsafe. However, we find that neonatal outcomes are no worse once selection bias is accounted for, and that the likelihood of severe obstetric hemorrhage is reduced. More widespread training of obstetricians in rotational instrumental delivery should be considered, particularly in light of rising cesarean delivery rates.During data analysis, A.R.A. was supported by an NICHD Predoctoral Fellowship under grant number F31HD079182 and by grant R24HD042849, awarded to the Population Research Center at The University of Texas at Austin. She is currently supported by grant R24HD047879 for Population Research at Princeton University. J.G.S. is partially funded by a CAREER grant from the National Science Foundation (DMS-1255187).This is the accepted version. It will be embargoed until 12 months after the final version is published by Elsevier. The final version is available from Elsevier at http://www.sciencedirect.com/science/article/pii/S000293781401078

Removal of terrestrial DOC in aquatic ecosystems of a temperate river network

Surface waters play a potentially important role in the global carbon balance. Dissolved organic carbon (DOC) fluxes are a major transfer of terrestrial carbon to river systems, and the fate of DOC in aquatic systems is poorly constrained. We used a unique combination of spatially distributed sampling of three DOC fractions throughout a river network and modeling to quantify the net removal of terrestrial DOC during a summer base flow period. We found that aquatic reactivity of terrestrial DOC leading to net loss is low, closer to conservative chloride than to reactive nitrogen. Net removal occurred mainly from the hydrophobic organic acid fraction, while hydrophilic and transphilic acids showed no net change, indicating that partitioning of bulk DOC into different fractions is critical for understanding terrestrial DOC removal. These findings suggest that river systems may have only a modest ability to alter the amounts of terrestrial DOC delivered to coastal zones

Rotorcraft In-Flight Simulation Research at NASA Ames Research Center: A Review of the 1980's and plans for the 1990's

A new flight research vehicle, the Rotorcraft-Aircrew System Concepts Airborne Laboratory (RASCAL), is being developed by the U.S. Army and NASA at ARC. The requirements for this new facility stem from a perception of rotorcraft system technology requirements for the next decade together with operational experience with the Boeing Vertol CH-47B research helicopter that was operated as an in-flight simulator at ARC during the past 10 years. Accordingly, both the principal design features of the CH-47B variable-stability system and the flight-control and cockpit-display programs that were conducted using this aircraft at ARC are reviewed. Another U.S Army helicopter, a Sikorsky UH-60A Black Hawk, was selected as the baseline vehicle for the RASCAL. The research programs that influence the design of the RASCAL are summarized, and the resultant requirements for the RASCAL research system are described. These research programs include investigations of advanced, integrated control concepts for achieving high levels of agility and maneuverability, and guidance technologies, employing computer/sensor-aiding, designed to assist the pilot during low-altitude flight in conditions of limited visibility. The approach to the development of the new facility is presented and selected plans for the preliminary design of the RASCAL are described