This article considers the application of the simulation-extrapolation (SIMEX) method for measurement error correction when the error variance is a function of the latent variable being measured. Heteroskedasticity of this form arises in educational and psychological applications with ability estimates from item response theory models. We conclude that there is no simple solution for applying SIMEX that generally will yield consistent estimators in this setting. However, we demonstrate that several approximate SIMEX methods can provide useful estimators, leading to recommendations for analysts dealing with this form of error in settings where SIMEX may be the most practical option.

Guidelines for the housing of dairy cows do not address the provision of supplementary lighting in passageways, other than for inspection of the animals. Two experiments were conducted to investigate whether lighting passageways to various intensities influenced the locomotion of dairy cows. The first experiment compared the locomotion of dairy cows in a dark or lighted passageway as they walked back to their accommodation from milking. When the passageway was dark, the cows took shorter but more rapid steps - which probably increased their stability. In the second experiment, cows walked down a cubicle passageway to receive a food reward, with the light intensity in the building varying from 0-250 lux. Step length and stepping rate were recorded, as well as the angles of the cows’ leg joints (which were measured from video recordings). Once again, the cows increased their stepping rate in the dark, and this resulted in an increased walking rate, perhaps because they wished to return more rapidly to other members of their group and found the darkness aversive. In addition, the arcs of travel of the metacarpophalangeal joint and of the fore- and hindfeet angles to the floor were reduced in the dark, probably increasing the cows’ stability, and were greatest at 119 lux. The slowest walking rate was observed at 39 lux. Hence, the optimum illumination for dairy cow locomotion may lie approximately between 39 and 119 lux, as measured by our technique.

We conclude that during locomotion in dark passageways cows have to modify their walking behaviour significantly, so that the provision of at least a low level of lighting is desirable at night.

Sea-level rise threatens both human communities and vulnerable species within coastal areas. Joint spatial planning can allow conservation and social resiliency goals to work in synergy. We present a case study integrating distribution information of a threatened saltmarsh bird, the eastern black rail (Laterallus jamaicensis jamaicensis), with social information to facilitate such joint planning. We constructed a distribution model for the species within an urbanizing coastal region (New Jersey, USA) and integrated this with publicly available parcel and protected area data to summarize ownership patterns. We estimated that c. 0.3–2.8% (c. 260–2200 ha) of available saltmarsh is occupied by eastern black rail, most of which is publicly owned (79%). Privately owned saltmarsh was spread across nearly 5000 individual parcels, 10% of which contained areas with the highest likelihood of rail presence according to our model (top quartile of predicted occupancy probabilities). Compared with all privately owned saltmarsh, parcels with probable rail habitat were larger (median: 5 versus 2 ha), contained more marsh (87% versus 59%) and were less economically valuable (US$11 200 versus US$36 100). Our approach of integrating species distributions with landownership data helps clarify trade-offs and synergies in species conservation and coastal resiliency planning.

Background: In patients with acute hip fracture, a fascia iliaca compartment block (FICB) has been shown to provide effective non-opioid analgesia, reduce the incidence of pneumonia, and potentially decrease the rate of delirium [1]. However, this procedure was infrequently used in the St. Michael's Hospital (SMH) emergency department (ED). Aim Statement: Our aim was to increase the proportion of patients with hip fracture receiving FICB in the ED to 50% in six months. Measures & Design: We completed two Plan-Do-Study-Act (PDSA) cycles, measuring rates of FICB before and after each cycle. The first was a departmental rounds presentation with information about the process and benefits of FICB, addressing barriers identified by surveying the group. The second cycle included a bundle of interventions comprising of an “instruction card” with the steps required to do the procedure, access to a video tutorial, and a list of experienced physicians willing to help less experienced providers perform FICB. Evaluation/Results: In the three months prior to the project, the rate of FICB in the ED was 12.5% (3/24). For the three months after the first PDSA cycle, the rate increased to 22.2% (8/36). Then, the second cycle was performed. In the following two months the rate further increased to 36.8% (7/19). Discussion/Impact: Despite the clear increase in FICB rate, these changes were not statistically significant (p = 0.063). Our methodology was shown to be safe and effective, and our model can be applied to other ED groups looking to increase their rates of FICB.

Introduction: A proportion of Emergency Department (ED) visits may be treated in out-of-hospital settings. The objective of this curriculum was to expand paramedic competencies to safely risk stratify patients and divert low risk, low acuity patients from EDs with and without physician oversight. Methods: We followed Kerns 6-step Curriculum Development Framework . (a) We identified a problem, and (b) completed a needs assessment by retrospectively reviewing the clinical pathways of 3000 patients were cared for and transported by paramedics and received care at an EDs. We used this data to identify competencies (e.g., diagnostics, interventions, reasoning needs) and targeted patient types that would result in the most significant advancements to paramedic services. These were translated to (c) goals and objectives. Results: Our (d) educational strategies involved a 14-week intensive patient-type and case-based curriculum. (e) Implementation involved 3 days/wk of clinical rotations supplemented with 2 days/wk of a mixed curriculum (i.e., fixed instruction using blended didactic small and large group sessions; flexible/individualized curriculum based on identified needs; formative assessments; self and peer-directed learning; simulations). (f) Assessment involved knowledge and application tests, clinical placement and simulation assessments; case development, assignments, and OSCE. Evaluation outcomes included student performance scores across 7-dimensions, clinical placement and student feedback. Thirteen Advanced Care Paramedics from York Region Paramedic Services completed the program. Challenges included provincial stakeholder consensus, and formally addressing clinical suspicion in a protocol based field within a limited time frame. Conclusion: A curriculum for expanded paramedic practice to risk stratify and divert targeted low risk patients from EDs resulted in new paramedic competencies and scope of practice. It received high evaluations from clinical staff and students. Successful candidates will undergo a 1-year study for validation and safety.

Reconstructions of long-term solar variability underpin our understanding of the solar dynamo, potential tropospheric climate implications and future space weather scenarios. Prior to direct spacecraft measurements of the heliospheric magnetic field (HMF) and solar wind, accurate annual reconstructions are possible using geomagnetic and sunspot records. On longer timescales, information about the HMF can be extracted from cosmogenic radionuclide records, particularly 14C in ancient trees and 10Be in ice sheets. These proxies, and what they reveal about the HMF and solar wind, are briefly reviewed here.

Vitamin E and selenium have been reported to improve immune function across a range of species. Ewes lambing on poor-quality dry pasture in autumn in Western Australia are at risk of being deficient in vitamin E and selenium at lambing thus predisposing their lambs to deficiencies and increasing the risk of infection and disease. This study tested the hypotheses that (i) supplementation of autumn-lambing ewes with vitamin E plus selenium in late gestation will increase the concentrations of vitamin E and selenium in plasma in the ewe and lamb and (ii) that the increased concentrations of vitamin E and selenium in plasma in the lambs will improve their innate and adaptive immune responses and thus survival. Pregnant Merino ewes were divided into a control group (n=58) which received no supplementation or a group supplemented with vitamin E plus selenium (n=55). On days 111, 125 and 140 of pregnancy ewes in the vitamin E plus selenium group were given 4 g all-rac-α-tocopherol acetate orally. On day 111 the ewes were also given 60 mg of selenium as barium selenate by subcutaneous injection. The concentrations of α-tocopherol and selenium were measured in ewes and/or lambs from day 111 of pregnancy to 14 weeks of age±10 days (weaning). Immune function of the lamb was assessed by analysing the numbers and phagocytic capacities of monocytes and polymorphonuclear leucocytes and plasma IgG and anti-tetanus toxoid antibody concentrations between birth and 14 weeks of age±10 days. Maternal supplementation with vitamin E plus selenium increased the concentration of α-tocopherol in plasma (1.13 v. 0.67 mg/l; P<0.001) and selenium in whole blood (0.12 v. 0.07 mg/l; P<0.01) of the ewes at lambing compared with controls. Supplementation also increased the concentration of α-tocopherol (0.14 v. 0.08 mg/l; P<0.001) and selenium (0.08 v. 0.05 mg/l; P<0.01) in lambs at birth compared with controls. There was no significant effect of supplementation on immune function or survival in the lambs.

The theory of the flow past cascades or infinite series of aerofoils, regularly spaced, is of importance in connection with the design of turbo-blower blades, interference between propeller blade root sections, wind tunnel circuit design and kindred problems. The usual development of the theory involves some rather advanced applications of conformal representation which it is rather difficult to translate into numerical terms, and no general solution for an arbitrary form of aerofoil section is available.

Vortices are not usually treated by potential theory, but the latter is so well known and of such general application that there seem to be advantages in doing so.

Consider first the potential function

i.e. distance from O.

Each small stage of the expansion starts with a uniform supersonic stream and finishes with a similar stream accelerated, expanded and turned through a small angle. We are therefore justified in applying to each stage the linear (Ackeret) approximation for small departures from uniform flow, according to which

where U = air velocity

M = Mach number

α = inclination of flow.

Problems involving discontinuous aerodynamic twist, as for a flapped wing, are not readily soluble for wings having a rectangular plan form or straight taper. Lotz's method (B.Ae.S. Journal, May, 1934) has been stated to be particularly suitable, but a recent American report used in preference a direct method of successive approximation. In either case a fair amount of labour is involved, and the final results are only approximate. The exact solution for a wing of elliptic plan form, whilst no-t directly applicable to the usual type of tapered monoplane wing, is readily obtainable, and should give a good idea of the lift distribution and induced drag due to a flap on an actual wing.

In 1931, several years before the RAE work on box wing theory which was mentioned (in the January Journal), I joined Armstrong Whitworth Aircraft. They were designing the Atalanta monoplane for Imperial Airways, and were in difficulties with the wing stressing, my chief H. A. Francis having, as he said, applied to RAE for advice and “got the bird”. The late J. K. Reid, their leading “methods man”, had already produced the simple exponential theory of uniform box torsion which RAE later re-discovered, but unfortunately, for our tapered thin-skin wing, we soon found out that this did not work.

Application of a method suggested by my technical note on equilateral and semi-equilateral triangles has yielded values for the buckling coefficients for isosceles triangles which in some cases differ appreciably from those given on Data Sheet 02.04.06.

The technical note quoted gives exact solutions in the form of a terminating trigonometrical series. When the triangle becomes isosceles, the series no longer terminates, but the infinite series solution, on insertion of the boundary conditions, gives an infinite determinant for the buckling load or eigenvalue.

Evaluation of the determinant, or of a sufficient number of terms, was computed on a Univac 1107, with the following results, which have been converted to the notation of Data Sheet 02.04.06.

The number of available exact solutions to the St. Venant flexure problem is limited, but there are some simple solutions which appear to have been overlooked. The sections covered are a wedge, a double wedge, a biconvex section, and an aerofoil-type section. All the solutions given are restricted to certain values of Poisson's ratio, depending on the section.

The components of shear stress parallel and perpendicular to the direction of loading are given by: