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The aim of this study was to demonstrate the use of testing for equivalence in combination with the Bland and Altman method when assessing agreement between two dietary methods. A sample data set, with eighty subjects simulated from previously published studies, was used to compare a FFQ with three 24 h recalls (24HR) for assessing dietary I intake. The mean I intake using the FFQ was 126·51 (sd 54·06) µg and using the three 24HR was 124·23 (sd 48·62) µg. The bias was −2·28 (sd 43·93) µg with a 90 % CI 10·46, 5·89 µg. The limits of agreement (LOA) were −88·38, 83·82 µg. Four equivalence regions were compared. Using the conventional 10 % equivalence range, the methods are shown to be equivalent both by using the CI (−12·4, 12·4 µg) and the two one-sided tests approach (lower t=−2·99 (79 df), P=0·002; upper t=2·06 (79 df), P=0·021). However, we make a case that clinical decision making should be used to set the equivalence limits, and for nutrients where there are potential issues with deficiency or toxicity stricter criteria may be needed. If the equivalence region is lowered to ±5 µg, or ±10 µg, these methods are no longer equivalent, and if a wider limit of ±15 µg is accepted they are again equivalent. Using equivalence testing, acceptable agreement must be assessed a priori and justified; this makes the process of defining agreement more transparent and results easier to interpret than relying on the LOA alone.
Motivated by processes occurring during
sequestration in an underground saline aquifer, we examine two-dimensional convection in a finite-depth porous medium induced by a solute introduced at the upper boundary. Once dissolved, the solute concentration is assumed to decay via a first-order chemical reaction, restricting the depth over which solute can penetrate the domain. Using spectral and asymptotic methods, we explore the resulting convective mixing using linear stability analysis, computation of nonlinear steady solution branches and time-dependent simulations, as a function of Rayleigh number, Damköhler number and domain size. Long-wave eigenmodes show how deep recirculation can be driven by a shallow solute field while explicit approximations are derived for the growth of short-wave eigenmodes. Steady solution branches undergo numerous secondary bifurcations, forming an intricate network of mixed states. Although many of these states are unstable, some play an important role in organising the phase space of time-dependent states, providing approximate bounds for time-averaged mixing rates.
We report on the preparation and characterization of crystalline bismuth oxide thin films via Biased Target Ion Beam Deposition method. A focused blue laser (405nm) is used to write an array of dots in the bismuth oxide thin film and demonstrate clear and circular recording marks in form of “bubbles” or “little volcanos” (FWHM ∼500nm). Results indicate excellent static recording characteristics, writing sensitivity and contrast. The recording mechanism is investigated and is believed to be related to laser-induced morphology change.
The use of whole-room calorimetry (WRC) in young children can increase our understanding of children's energy balance. However, studies using WRC in young children are rare due to concerns about its feasibility. To assess the feasibility of WRC in young children, forty children, aged 4–6 years, were asked to follow a graded activity protocol while in a WRC. In addition, six children participated in two additional resting protocols to examine the effect of diet-induced thermogenesis on resting energy expenditure (REE) measures and the reliability of REE measurement. Refusals to participate and data loss were quantified as measures of practical utility, and REE measured after an overnight fast and after a 90-min fast were compared. In addition, both were compared to predicted BMR values using the Schofield equation. Our results showed that thirty (78·9 %) participants had acceptable data for all intensities of the activity protocol. The REE values measured after a 90-min fast (5·07 (sd 1·04) MJ/d) and an overnight fast (4·73 (sd 0·61) MJ/d) were not significantly different from each other (P= 0·472). However, both REE after an overnight fast and a 90-min fast were significantly higher than predicted BMR (3·96 (sd 0·18) MJ/d) using the Schofield equation (P= 0·024 and 0·042, respectively). We conclude that, with a developmentally sensitive approach, WRC is feasible and can be standardised adequately even in 4- to 6-year-old children. In addition, the effect of a small standardised breakfast, approximately 90 min before REE measurements, is likely to be small.
This paper is concerned with the current and future financing of long-term care (LTC). This is defined as the provision of nursing and care services to those adults who are incapable, to some degree, of looking after themselves, but excluding short-term convalescent care. The current position is summarised, covering the demand and supply of LTC, how it is currently financed, new developments and consumer attitudes. The paper then goes on to consider future developments. Possible patterns of future demand, covering likely needs and costs are given. Consideration is then given as to how future demand may be financed.
The paper discusses some of the initiatives that might be undertaken to encourage proper planning by both the State and individuals and concludes that the actuarial profession should have a significant role to play in communicating the issues and evaluating solutions.
During the processing and packaging of silicon integrated circuits there are many sources of die stress. Probably the least understood and controlled is the stress introduced during the die attach and molding processes. The largest packaging stresses are due to the mismatch of the thermal expansion coefficients between the leadframe and the die,and the die and the molding material. We report results obtained by monitoring the resistance changes of implanted, p-type resistors, undergoing various heat treatments with a matrix of mold and leadframe materials.
We have developed a lipid-based microcylinder for the controlled release of biological response modifiers. Lipid microcylinders are composed of 1,2-ditricosa-10,12-diynoyl-sn-glycerol-3-phosphocholine which form hollow cylinders 50–250 μm in length with a diameter approximately 0.5–1.0 μm. Amphiphilic molecules such as ganglioside (5–6 mol%) can be incorporated into the bilayers of the microcylinder, modulating surface characteristics of the structure.
In this study, we have examined the biocompatibility of lipid microcylinders and lipid microcylinders containing 6 mol% ganglioside. The interaction of microcylinders with peripheral blood monocytes and three cell lines: U937, a histocytic monocyte; K562, an erythroblast, and; a Jurkat derivative, a lymphoblast was assessed. Toxicity, as measured by proliferative status of the cell lines, was not evident at lipid concentrations up to 100 μg/ml lipid. Peripheral blood monocytes were observed to closely associate, but not engulf lipid microcylinders. However, when ganglioside was present in the lipid microcylinders this interaction was markedly decreased.
We have begun to measure the release rates of growth factors such as transforming growth factor-beta (TGF-β) from lipid microcylinders. Release of TGF-β from the microcylinders follows first-order kinetics. The rate of release can be modulated by increasing the temperature which results in a thermotrophic phase transition of the lipid at 43 °C.
Grain boundary segregation of phosphorous in model reactor steels has been measured using EDX Spectroscopy in the FEG-STEM. The results have been compared with Auger spectroscopy measurements made on similar materials. The results were in excellent agreement.
A compressible air-flow model is introduced for the thin film dynamics of a highly rotating squeeze-film thrust bearing. The lubrication approximation to the Navier–Stokes equations for compressible flow leads to a modified Reynolds equation incorporating additional rotation effects. To investigate the dynamics of the system, the axial position of the bearing stator is prescribed by a finite-amplitude periodic forcing. The dynamics of the squeeze-film are modelled in the uncoupled configuration where the axial position of the rotor is fixed. The coupled squeeze-film bearing dynamics are investigated when the axial position of the rotor is modelled as a spring-mass-damper system that responds to the film dynamics. Initially the uncoupled squeeze-film dynamics are considered at low operating speeds with the classical Reynolds equation for compressible flow. The limited value of the linearized small-amplitude results is identified. Analytical results indicate that finite-amplitude forcing needs to be considered to gain a complete understanding of the dynamics. Using a Fourier spectral collocation numerical scheme, the periodic bearing force is investigated as a nonlinear function of the frequency and amplitude of the stator forcing. High-speed bearing operation is modelled using the modified Reynolds equation. A steady-state analysis is used to identify the effect of rotation and the rotor support properties in the coupled air-flow–structure model. The unsteady coupled dynamics are computed numerically to determine how the rotor support structures and the periodic stator forcing influence the system dynamics. The potential for resonant rotor behaviour is identified through asymptotic and Fourier analysis of the rotor motion for small-amplitude, low-frequency oscillations in the stator position for key values of the rotor stiffness. Through the use of arclength continuation, the existence of resonant behaviour is identified numerically for a range of operating speeds and forcing frequencies. Changes in the minimum rotor–stator clearance are presented as a function of the rotor stiffness to demonstrate the appearance of resonance.
Although the involvement of common childhood infections in the aetiology of acute appendicitis has long been conjectured, supporting evidence is largely restricted to a disparate set of clinical case reports. A systematic population-based analysis of the implied comorbid associations is lacking in the literature. Drawing on a classic epidemiological dataset, assembled by the School Epidemics Committee of the United Kingdom's Medical Research Council (MRC) in the 1930s, this paper presents a historical analysis of the association between termly outbreaks of each of six common childhood infections (chickenpox, measles, mumps, rubella, scarlet fever and whooping cough) and operated cases of acute appendicitis in 27 English public boarding schools. When controlled for the potential confounding effects of school, year and season, multivariate negative binomial regression revealed a positive association between the level of appendicitis activity and the recorded rate of mumps (β=0·15, 95% CI 0·07–0·24, P<0·001). Non-significant associations were identified between appendicitis and the other sample infectious diseases. Subject to data caveats, our findings suggest that further studies are required to determine whether the comorbid association between mumps and appendicitis is causal.
This study examined disaster preparedness, risk perception, and their association in rural hospitals in the United States. The focus of disaster preparedness largely has been centered on urban areas, in part because of the perception that more concentrated areas have an increased risk of a disastrous event. Therefore, it was hypothesized that risk perception may be a contributing factor for adequate preparedness in rural areas. This research was a component of a larger study of rural hospital preparedness. The objective of this study was to describe the perceived risk of disaster events and the status of disaster preparedness in rural hospitals. It was hypothesized that there is a positive association between risk perception and preparedness.
Secondary data analysis was conducted using the National Study of Rural Hospitals (2006–2007) from Johns Hopkins University. The study, based on a regionally stratified, random sample of rural hospitals, consisted of a mailed questionnaire and a follow-up telephone interview with each hospital's Chief Executive Officer (n = 134). A model of disaster preparedness was utilized to examine seven elements of preparedness. Risk perception was examined through seven perceived risk threats.
The results indicated that rural hospitals were moderately prepared, overall,(78% prepared on average), with higher preparedness in education/training (89%) and isolation/decontamination (91%); moderate preparedness in administration/planning (80%), communication/notification (83%), staffing/support (66%), and supplies/pharmaceuticals/laboratory support (70%); and lower preparedness in surge capacity (64%).
The respondents reported greater perceived risk from disasters due to natural hazards (79% reported moderate to high risk) and vehicular accidents (77%) than from humanmade disasters (23%). Results obtained from logistic regression models indicated that there was no statistically significant difference in the odds of a hospital being prepared overall when comparing high versus low risk perception (OR = 0.61; 95% CI = 0.26–1.44). Positive associations were identified only between higher perceived risk overall and the subcategory of education/training preparedness (OR = 1.24; 95% CI = 1.05–1.27).
Rural hospitals reported being moderately prepared in the event of a disaster with a low perception of risk for human-made disasters. Further research should be conducted to identify predictors of preparedness in rural hospitals in order to optimize readiness for potential disaster events.
We compared helminth communities in spiny mice (Acomys dimidiatus) from 4 wadis in the arid montane region of the southern Sinai in Egypt, in a 4-week period in late summer. Total helminth species richness was 14 (8 nematodes, 5 cestodes and 1 acanthocephalan) with 94% of mice carrying at least 1 species and an overall mean species richness of 1·85. The most prevalent parasites were Protospirura muricola (47·8%) and Dentostomella kuntzi (46·3%). One larval cestode, Joyeuxiella rossicum, represents a new host record. The helminth community was dominated by intestinal nematodes (88·7%) of which 58·2% were arthropod-transmitted heteroxenic species. At the component community level, 70% of the worms were recovered from mice in just two wadis (Gharaba and Tlah) and 48·6% of intestinal nematodes were from Wadi Gharaba. Although only 7 species of helminths were recorded from Wadi Gharaba, this site gave the highest Berger-Parker dominance index because of P. muricola. P. muricola was also dominant in Wadi El Arbaein whilst Syphacia minuta was the dominant species in Wadis Gebal and Tlah. At the infracommunity level, mean species richness and Brillouin's index of diversity were highest in Wadi Tlah and lowest in Wadi Gebal, and the former was age dependent. Whilst mice from different wadis differed in the nematodes that were most common, those from Wadi Gharaba carried the highest mean number of worms/mouse. The abundance of P. muricola in particular varied markedly between sites: Wadi Gharaba was distinct as the site showing the highest mean worm burden whereas mice from Wadi Gebal were uninfected. None of the directly transmitted oxyuroid nematodes showed significant variation in abundance between wadis, or host sex or age classes. Overall, the single extrinsic factor in the study, site of capture, was more important than the intrinsic factors in explaining variation in helminth communities in the region. We conclude that in the high mountains of southern Sinai, each wadi is distinct in terms of its rodent parasites, and hence we expect spatially different coevolutionary pressures on their hosts, with resultant variation in life-histories.
The steady two-dimensional laminar flow past a stationary cylinder is well known to lose stability to a periodic flow at a supercritical Hopf bifurcation point as the flow rate is increased. It is less well known that the critical flow rate at which the instability occurs can be increased by rotating the cylinder about is own axis, and that at a fixed flow rate the vortex street can be eliminated entirely by sufficiently large rotation. We confine the flow between two parallel walls and report the effect of cylinder rotation on the Reynolds number and frequency at the Hopf bifurcation point. Two new, and somewhat surprising, results are that for stationary cylinders at large blockage ratios, the steady symmetric flow can restabilize above a critical Reynolds number, and that steady asymmetric flows exist.
The effect of boundary conditions on the ‘critical dynamics’ at the onset of Taylor vortices is investigated in a combined numerical and experimental study. Numerical calculations of Navier–Stokes equations with ‘stress-free’ boundary conditions show that the Landau amplitude equation provides a good model of the transient dynamics. However, this rapidly breaks down when the ‘no-slip’ condition is approached. Apparent ‘critical’ behaviour observed in experiments is shown to have a surprising dependence on the length of the system.