Blood product transfusion in emergency department patients: A case-control study of practice patterns and impact on outcome

Definitions of comorbid conditions. (DOCX 13 kb

The role of body shape and mass in skimming on water

Over many years, there has been great practical interest in how solid bodies interact with and skim on liquid layers. In the present investigation, the focus is on the important role of body mass and shape in such skimming motions. Considering a thin two-dimensional solid body that impacts obliquely and then rebounds on a shallow inviscid water layer, we develop a mathematical model to predict quantitatively the duration and evolution of the body and fluid motions and indeed the success or failure of the whole skim. In the current setting, the shallow water layer thickness is small relative to the representative body length. The combined roles of increased mass and shape are found to be crucial, governed by a similarity solution. The relationship C ∼ M2/3 between scaled body curvature and mass is identified and highlighted. In particular, increased convex curvature of the underbody is found to alter the interactive pressure in such a way that it inhibits the occurrence of a super-elastic response in the exit vertical velocity and height of the body, and in effect enables a much heavier body to skim successfully provided the above relationship is maintained

A body in nonlinear near-wall shear flow:impacts, analysis and comparisons

Interaction between body motion and fluid motion is considered inside a nonlinear viscous wall layer, with this unsteady two-way coupling leading to impact of the body on the wall. The present paper involves a reduced system analysis which is shown to be consistent with computational solutions from direct numerical simulations for a basic flat-plate shape presented in an allied paper (Palmer & Smith, J. Fluid Mech., 2020). The occurrence of impact depends mainly on fluid parameters and initial conditions. The body considered is translating upstream or downstream relative to the wall. Subsequent analysis focusses on the unusual nature of the impact at the leading edge. The impacting flow structure is found to have two nonlinear viscous–inviscid regions lying on either side of a small viscous region. The flow properties in the regions dictate the lift and torque which drive the body towards the wall. Pronounced flow separations are common as the impact then cuts off the mass flux in the gap between the body and the wall; here, a nonlinear similarity solution sheds extra light on the separations. Comparisons are made between results from direct simulations and asymptotics at increased flow rate

Skimming impact of a thin heavy body on a shallow liquid layer

This study addresses the question of whether a thin, relatively heavy solid body with a smooth under-surface can skim on a shallow layer of liquid (for example water), i.e. impact on the layer and rebound from it. The body impacts obliquely onto the liquid layer with the trailing edge of the underbody making the initial contact. The wetted region then spreads along the underbody and eventually either retracts, generating a rebound, or continues to the leading edge of the body and possibly leads to the body sinking. The present inviscid study involves numerical investigations for increased mass ( M , in scaled terms) and moment of inertia ( I , proportional to the mass) together with an asymptotic analysis of the influential parameters and dynamics at different stages of the skimming motion. Comparisons between the asymptotic analysis and numerical results show close agreement as the body mass becomes large. A major finding is that, for a given impact angle of the underbody relative to the liquid surface, only a narrow band of initial conditions is found to allow the heavy-body skim to take place. This band includes reduced impact velocities of the body vertically and rotationally, both decreasing like M−2/3 , while the associated total time of the skim from entry to exit is found to increase like M1/3 typically. Increased mass thereby enhances the super-elastic behaviour of the skim

Enhanced Oceanic Operations Human-In-The-Loop In-Trail Procedure Validation Simulation Study

The Enhanced Oceanic Operations Human-In-The-Loop In-Trail Procedure (ITP) Validation Simulation Study investigated the viability of an ITP designed to enable oceanic flight level changes that would not otherwise be possible. Twelve commercial airline pilots with current oceanic experience flew a series of simulated scenarios involving either standard or ITP flight level change maneuvers and provided subjective workload ratings, assessments of ITP validity and acceptability, and objective performance measures associated with the appropriate selection, request, and execution of ITP flight level change maneuvers. In the majority of scenarios, subject pilots correctly assessed the traffic situation, selected an appropriate response (i.e., either a standard flight level change request, an ITP request, or no request), and executed their selected flight level change procedure, if any, without error. Workload ratings for ITP maneuvers were acceptable and not substantially higher than for standard flight level change maneuvers, and, for the majority of scenarios and subject pilots, subjective acceptability ratings and comments for ITP were generally high and positive. Qualitatively, the ITP was found to be valid and acceptable. However, the error rates for ITP maneuvers were higher than for standard flight level changes, and these errors may have design implications for both the ITP and the study's prototype traffic display. These errors and their implications are discussed

Perfect weddings abroad

Approximately 16% of UK couples are currently married abroad. However, academic or practitioner focused research that explores the complex nature of a couple’s buying preferences or the development of innovative marketing strategies by businesses operating within the weddings abroad niche sector, is almost non-existent. This exploratory paper examines the role and relevance of marketing within the weddings abroad sector. The complex nature of customer needs in this high emotional and involvement experience, are identified and explored. A case study of Perfect Weddings Abroad Ltd highlights distinctive features and characteristics. Social networking and the use of home-workers, with a focus on reassurance and handholding are important tools used to develop relationships with customers. These tools and techniques help increase the tangibility of a weddings abroad package. Clusters of complementary services that are synergistic and provide sources of competitive advantage are identified and an agenda for future research is developed

Kauri Tree-Ring Stable Isotopes Reveal a Centennial Climate Downturn Following the Antarctic Cold Reversal in New Zealand

The dynamics of the Late Glacial have been demonstrated by numerous records from the Northern Hemisphere and far fewer from the Southern Hemisphere (SH). SH paleoclimate records reveal a general warming trend, interrupted by a deglaciation pause Antarctic Cold Reversal (ACR; ∼14,700–13,000 cal BP). Here, we present decadal tree-ring stable isotope chronologies (δ18O, δ13C) from New Zealand (NZ) subfossil kauri trees (n = 6) covering the post-ACR millennium from 13,020 to 11,850 cal BP. We find a distinct, simultaneous downturn (∼12,625–12,375 cal BP) in all tree-ring proxies paralleling regional tree growth declines, suggesting a widespread climate deterioration. This downturn was characterized by sustained high precipitation, low temperatures, and high relative humidity in NZ with incoming weather fronts from the South Ocean. Despite these promising results, questions remain about what drove the Kauri Downturn and how the hydroclimatic conditions were altered during this time period

Tools to Assess Behavioral and Social Science Competencies in Medical Education: A Systematic Review

Behavioral and social science (BSS) competencies are needed to provide quality health care, but psychometrically validated measures to assess these competencies are difficult to find. Moreover, they have not been mapped to existing frameworks, like those from the Liaison Committee on Medical Education (LCME) and Accreditation Council for Graduate Medical Education (ACGME). This systematic review aimed to identify and evaluate the quality of assessment tools used to measure BSS competencies

Comparison of Airborne and Ground-Based Function Allocation Concepts for NextGen Using Human-In-The-Loop Simulations

This paper presents an air/ground functional allocation experiment conducted by the National Aeronautics and Space Administration (NASA) using two human-in-the-Loop simulations to compare airborne and ground-based approaches to NextGen separation assurance. The approaches under investigation are two trajectory-based four-dimensional (4D) concepts; one referred to as "airborne trajectory management with self-separation" (airborne) the other as "ground-based automated separation assurance" (ground-based). In coordinated simulations at NASA's Ames and Langley Research Centers, the primary operational participants -controllers for the ground-based concept and pilots for the airborne concept - manage the same traffic scenario using the two different 4D concepts. The common scenarios are anchored in traffic problems that require a significant increase in airspace capacity - on average, double, and in some local areas, close to 250% over current day levels - in order to enable aircraft to safely and efficiently traverse the test airspace. The simulations vary common independent variables such as traffic density, sequencing and scheduling constraints, and timing of trajectory change events. A set of common metrics is collected to enable a direct comparison of relevant results. The simulations will be conducted in spring 2010. If accepted, this paper will be the first publication of the experimental approach and early results. An initial comparison of safety and efficiency as well as operator acceptability under the two concepts is expected

Comparison of Ground-Based and Airborne Function Allocation Concepts for NextGen Using Human-In-The-Loop Simulations

Investigation of function allocation for the Next Generation Air Transportation System is being conducted by the National Aeronautics and Space Administration (NASA). To provide insight on comparability of different function allocations for separation assurance, two human-in-the-loop simulation experiments were conducted on homogeneous airborne and ground-based approaches to four-dimensional trajectory-based operations, one referred to as ground-based automated separation assurance (groundbased) and the other as airborne trajectory management with self-separation (airborne). In the coordinated simulations at NASA s Ames and Langley Research Centers, controllers for the ground-based concept at Ames and pilots for the airborne concept at Langley managed the same traffic scenarios using the two different concepts. The common scenarios represented a significant increase in airspace demand over current operations. Using common independent variables, the simulations varied traffic density, scheduling constraints, and the timing of trajectory change events. Common metrics were collected to enable a comparison of relevant results. Where comparisons were possible, no substantial differences in performance or operator acceptability were observed. Mean schedule conformance and flight path deviation were considered adequate for both approaches. Conflict detection warning times and resolution times were mostly adequate, but certain conflict situations were detected too late to be resolved in a timely manner. This led to some situations in which safety was compromised and/or workload was rated as being unacceptable in both experiments. Operators acknowledged these issues in their responses and ratings but gave generally positive assessments of the respective concept and operations they experienced. Future studies will evaluate technical improvements and procedural enhancements to achieve the required level of safety and acceptability and will investigate the integration of airborne and ground-based capabilities within the same airspace to leverage the benefits of each concept