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Objectives: This study aimed to evaluate the influence of lower limb loss (LL) on mental workload by assessing neurocognitive measures in individuals with unilateral transtibial (TT) versus those with transfemoral (TF) LL while dual-task walking under varying cognitive demand. Methods: Electroencephalography (EEG) was recorded as participants performed a task of varying cognitive demand while being seated or walking (i.e., varying physical demand). Results: The findings revealed both groups of participants (TT LL vs. TF LL) exhibited a similar EEG theta synchrony response as either the cognitive or the physical demand increased. Also, while individuals with TT LL maintained similar performance on the cognitive task during seated and walking conditions, those with TF LL exhibited performance decrements (slower response times) on the cognitive task during the walking in comparison to the seated conditions. Furthermore, those with TF LL neither exhibited regional differences in EEG low-alpha power while walking, nor EEG high-alpha desynchrony as a function of cognitive task difficulty while walking. This lack of alpha modulation coincided with no elevation of theta/alpha ratio power as a function of cognitive task difficulty in the TF LL group. Conclusions: This work suggests that both groups share some common but also different neurocognitive features during dual-task walking. Although all participants were able to recruit neural mechanisms critical for the maintenance of cognitive-motor performance under elevated cognitive or physical demands, the observed differences indicate that walking with a prosthesis, while concurrently performing a cognitive task, imposes additional cognitive demand in individuals with more proximal levels of amputation.
We provide an update on diagnostic methods for the detection of urogenital schistosomiasis (UGS) in men and highlight that satisfactory urine-antigen diagnostics for UGS lag much behind that for intestinal schistosomiasis, where application of a urine-based point-of-care strip assay, the circulating cathodic antigen (CCA) test, is now advocated. Making specific reference to male genital schistosomiasis (MGS), we place greater emphasis on parasitological detection methods and clinical assessment of internal genitalia with ultrasonography. Unlike the advances made in defining a clinical standard protocol for female genital schistosomiasis, MGS remains inadequately defined. Whilst urine filtration with microscopic examination for ova of Schistosoma haematobium is a convenient but error-prone proxy of MGS, we describe a novel low-cost sampling and direct visualization method for the enumeration of ova in semen. Using exemplar clinical cases of MGS from our longitudinal cohort study among fishermen along the shoreline of Lake Malawi, the portfolio of diagnostic needs is appraised including: the use of symptomatology questionnaires, urine analysis (egg count and CCA measurement), semen analysis (egg count, circulating anodic antigen measurement and real-time polymerase chain reaction analysis) alongside clinical assessment with portable ultrasonography.
This study details the characterization of a glass sample exposed to hyperalkaline water and calcium-rich sediment for an extended time period (estimated as 2 - 70 years) at a lime (CaO) waste site in the UK. We introduce this site, known as Peak Dale, in reference to its use as a natural analogue for nuclear waste glass dissolution in the high pH environment of a cementitious engineered barrier of a geological disposal facility. In particular, a preliminary assessment of alteration layer chemistry and morphology is described and the initiation of a long-term durability assessment is outlined.
We describe an X-ray polarimeter which will be flown on the SPECTRUM-X-Gamma mission. The instrument exploits three distinct physical processes to measure polarization: Bragg reflection from a graphite crystal, Thomson scattering from a metallic lithium target, and photoemission from a Cesium Iodide photocathode. These three processes allow polarization measurements over an energy band of 0.3 keV to 12 keV. The polarimeter will make possible sensitive measurements of several hundred known X-ray sources. X-ray polarization measurements will allow us to constrain the geometry of gas flow in X-ray binaries, identify nonthermal emission in supernova remnants, test current models for X-ray emission in radio pulsars, determine the radiation mechanisms in active galactic nuclei, and search for inertial frame dragging (Lense-Thirring effect) around the putative black hole in Cygnus X-1.
Parental depressive symptoms are associated with emotional and behavioural problems in offspring. However, genetically informative studies are needed to distinguish potential causal effects from genetic confounds, and longitudinal studies are required to distinguish parent-to-child effects from child-to-parent effects.
We conducted cross-sectional analyses on a sample of Swedish twins and their adolescent offspring (n = 876 twin families), and longitudinal analyses on a US sample of children adopted at birth, their adoptive parents, and their birth mothers (n = 361 adoptive families). Depressive symptoms were measured in parents, and externalizing and internalizing problems measured in offspring. Structural equation models were fitted to the data.
Results of model fitting suggest that associations between parental depressive symptoms and offspring internalizing and externalizing problems remain after accounting for genes shared between parent and child. Genetic transmission was not evident in the twin study but was evident in the adoption study. In the longitudinal adoption study child-to-parent effects were evident.
We interpret the results as demonstrating that associations between parental depressive symptoms and offspring emotional and behavioural problems are not solely attributable to shared genes, and that bidirectional effects may be present in intergenerational associations.
This paper describes the system architecture of a newly constructed radio telescope – the Boolardy engineering test array, which is a prototype of the Australian square kilometre array pathfinder telescope. Phased array feed technology is used to form multiple simultaneous beams per antenna, providing astronomers with unprecedented survey speed. The test array described here is a six-antenna interferometer, fitted with prototype signal processing hardware capable of forming at least nine dual-polarisation beams simultaneously, allowing several square degrees to be imaged in a single pointed observation. The main purpose of the test array is to develop beamforming and wide-field calibration methods for use with the full telescope, but it will also be capable of limited early science demonstrations.
The Authors are members of a Working Party established by the Councils of the Faculty and Institute to consider the Department of Trade's proposed Rules for valuing the liabilities of long-term business.
The paper opens with a short introduction followed by Part 2 which considers the control systems operating in several overseas territories. Part 3 is largely historical and traces the development of actuarial thought and practice since the war. The negotiations in Europe are also covered. Having set the scene, the Authors move to consideration of the Department of Trade's proposals (the proposed Rules for valuation of liabilities are included as an Appendix to the Paper). After a brief description of the proposed Asset Value Regulations in Part 4 the net premium valuation method is discussed in Part 5 and the problems of large fluctuations in the interest basis are illustrated by examples. Possible modifications to the conventional formula are explored with further examples. The elements of the valuation basis are discussed in turn with particular emphasis on the valuation rate of interest.
The Authors conclude that the problems arising from use of high rates of interest in valuation are not so much a function of the inadequacy of the valuation method as an indication of the real financial strains to which offices are exposed in current conditions. The paper ends with a reminder that with the varied traditions of the British market no one set of Valuation Rules can satisfactorily cover every special case. Any statutory basis therefore must be seen as a compromise, and the Authors touch on special cases where they feel that it would be appropriate for the authorities to exercise their discretionary powers.
The paper is an investigation into the withdrawal rates of seven Scottish Offices and covers the years 1972-76 with an appendix giving the results for 1977.
The rates were basically analysed by class and duration with further investigations mainly on the 1976 data by age at entry, sex, size of sum assured, premium paying term, premium payment frequency and by type of agent introducing the business. Comparisons were made of the level of withdrawal rates among the various Offices and also the variations from year to year separately. A graduation of the combined data for 1975 and 1976 for each of the five main classes was carried out.
The role of interfacial exchange coupling in the magnetic behavior of metal oxide materials has been investigated through the study of Fe3O4/NiO superlattices. We report results on a series of superlattices grown where one bilayer constituent was held to a fixed thickness while varying the other from single unit cell dimensions upward. High crystalline quality was confirmed by XRD, RHEED and neutron diffraction. Magnetization profiles show substantial deviations from bulklike iron oxide results, with an increase in domain rotation energies observed in the superlattices over that of bulk iron oxide (increasing with NiO layer thickness) indicating the strong nature of Fe3O4/NiO interfacial linkage. Neutron scattering at elevated temperatures shows that the NiO remains ordered above the 523 K bulk Néel temperature. This suggests that at least a portion of the NiO within a layer remains ordered well above the Néel temperature, with an increase in effective Néel transition temperature that approaches the Fe3O4 Curie temperature in the limit of very thin NiO layers. Although the exchange coupling dominates these effects, strain also plays an important role.
We have developed a chemical kinetics simulation that can be used as both an educational
and research tool. The simulator is designed as an accessible, open-source project that
can be run on a laptop with a student-friendly interface. The application can potentially
be scaled to run in parallel for large simulations. The simulation has been successfully
used in a classroom setting for teaching basic electrochemical properties. We have shown
that this can be used for simulating fundamental molecular and chemical processes and even
simplified models of predator–prey interactions. By giving the simulated entities spatial
extent in the lattice, the particles do not interpenetrate, and clusters of particles can
spatially exclude one another. Our simulation demonstrates that spatial inhomogeneity
leads to different results than those that are obtained by using standard ordinary
differential equation models, as previously reported.
The application of some characterization methods to the study of heteroepitaxy is illustrated by recent work in the authors laboratory on the epitaxy of Cu on Mo and W(110). In particular, the use of PEEM and LEEM in the study of the epitaxy of Cu, Au and Co on Si(111) is discussed.
In this paper present experimental results on the quality of AIGaAs material after high concentrations of impurities have been introduced for the purpose of impurity induced disordering. A comparison between Zn and Si diffusion is presented, and the nature of the transition region between uniform alloy and as-grown periodic structure has been characterized both experimentally and theoretically. Device implications of these observations is discussed.
The structural quality of GaAs/Si layers deposited directly at the normal growth temperatures (650°C,750°C) is compared with that of layers grown by the standard two-step growth process using Metalorganic Chemical Vapor Deposition (MOCVD). The directly grown layers are highly twinned and polycrystalline in nature whereas the two step growth process produces single crystal layers even at growth temperatures as high as 800°C. The origin of these effects is related to the initial growth of the GaAs, which is in the form of highly defective separate islands, for the case of direct growth, and connected single crystal islands for the case of two-step growth. The directly grown islands exhibit a “ripening” type behavior, with a strong dependence of the Si substrate surface coverage by the GaAs layer, on the growth temperature. The generation of structural defects such as stacking faults and microtwins, which destroy the epitaxial relationship could be triggered by the presence of surface imperfections on the Si substrate.
Wedge Transmission Electron Microscopy has many advantages, one of which is the concentration determination in III-V semiconductors with a fairly good accuracy. This allows us to determine the concentration variation during the growth of GaInAs/InP multilayered structures and to deduce the concentration grading at the interface GaInAs/InP (As in InP) and the abruptness of the InP/GaInAs interface.