Organization of the musculature of schistosome cercariae

Phalloidin-fluorescein isothiocyanate staining of filamentous actin was used to identify muscle systems within the cercariae of Schistosoma mansoni. Examination of labeled cercariae by confocal scanning laser microscopy revealed distinct organizational levels of myofiber arrangements within the body wall, anterior cone, acetabulum, and esophagus. The body wall throughout showed a typical latticelike arrangement of outer circular and inner longitudinal myofibers, with an additional innermost layer of diagonal fibers in the anterior portion of the body. Circular and longitudinal fibers were also evident in the anterior organ and esophagus and. to some extent, the ventral acetabulum. Most striking was the striation of the cercarial tail musculature.

Under-water scene investigation using ground penetrating radar (GPR) in the search for a sunken jet ski, Northern Ireland

A search for a submerged jet ski and the lost limb of its driver involved in a collision with a speedboat was made in a shallow lake in Northern Ireland. The location of both was crucial to establishing events at the time of the accident. Local intelligence suggested both objects were likely to be partially-buried by lacustrine silt. To avoid sediment churning, this required non-invasive, completely non-destructive assessment and mapping of the scene. A MALA RAMAC ground-penetrating radar system (GPR) mounted on floats for surveying from walkways and jetties or placed in a small rubber dinghy for offshore profiling was used. A grid was established and each line surveyed with 100, 200 and 400MHz antennae. In waters over 6m deep GPR data showed the form of the lake floor but excessive ringing occurred in the data. In waters less than 6m deep ringing diminished on both 100 and 200MHz data, the latter displaying the best trade-off between depth penetration and horizontal object resolution. 400MHz data failed to be of use in waters over 2m deep and at these depths showed only limited improvement of image quality compared to 200MHz data. Surface objects such as a wooden walkway caused interference on 200 and 400MHz data when antennae were oriented both normal and parallel to survey direction; this may be a function of the low attenuation of radar waves in freshwater, allowing excellent lateral and vertical radar wave penetration. On 200MHz data the damaged jet-ski was clearly imaged in a location that contradicted the speedboat driver's account of the accident.

Common input to different regions of biceps brachii long head

The purpose of the experiment was to compare the level of synchronization exhibited by pairs of motor units located within and between functionally distinct regions of the biceps brachii muscle. Pairs of single motor units were recorded from seven subjects using separate electrodes located in the lateral and medial aspects of the long head of biceps brachii. Participants were required to exert a combination of flexion and supination torques so that both motor units discharged at approximately 10 pps for a parts per thousand yen200 s and the level of motor unit synchronization could be quantified. When motor unit recordings were sufficiently stable at the completion of this synchrony task, a series of ramp contractions with multiple combinations of flexion and supination torques were performed to characterize the recruitment thresholds of the motor units. Common input strength (CIS) was significantly greater (P <0.01) for the within-region pairs of motor units (0.28 extra sync. imps/s, n = 26) than for the between-region pairs (0.13 extra sync. imps/s, n = 18), but did not differ significantly for the 12 within-region pairs from the lateral head and 14 from the medial head (0.27 vs. 0.29 extra sync. imps/s; P = 0.83). Recruitment thresholds were measured for 33 motor units, but there was only a weak association between CIS and the respective recruitment patterns for motor unit pairs (n = 9). The present investigation provides evidence of a differential distribution of synaptic input across the biceps brachii motor neuron pool, but this appears to have minimal association with the recruitment patterns for individual motor units.

Novel loading tests on full-scale tapered member portal frames

This paper presents the experimental results of loading tests on two 18m span tapered member portal frames designed to BS 5950. Deflection test results for vertical, lateral and combined loading cases are compared with the predictions given by elastic analysis to BS 5950 and shown to be favourable. The predicted ultimate capacities and modes of failure, which were by lateral-torsional buckling of the columns, were also found to agree with the experimental behaviour. It was found that the method of modelling the tapered members as a series of prismatic elements gave good comparison with test results.

Decoupled-DFIG fault ride-through strategy for enhanced stability performance during grid faults

This paper proposes a decoupled fault ride-through strategy for a doubly fed induction generator (DFIG) to enhance network stability during grid disturbances. The decoupled operation proposes that a DFIG operates as an induction generator (IG) with the converter unit acting as a reactive power source during a fault condition. The transition power characteristics of the DFIG have been analyzed to derive the capability of the proposed strategy under various system conditions. The optimal crowbar resistance is obtained to exploit the maximum power capability from the DFIG during decoupled operation. The methods have been established to ensure proper coordination between the IG mode and reactive power compensation from the grid-side converter during decoupled operation. The viability and benefits of the proposed strategy are demonstrated using different test network structures and different wind penetration levels. Control performance has been benchmarked against existing grid code standards and commercial wind generator systems, based on the optimal network support required (i.e., voltage or frequency) by the system operator from a wind farm installed at a particular location.

Platyhelminth FMRFamide-related peptides

Platyhelminths are the most primitive metazoan phylum to possess a true central nervous system, comprising a brain and longitudinal nerve cords connected by commissures. Additional to the presence of classical neurotransmitters, the nervous systems of all major groups of flatworms examined have widespread and abundant peptidergic components, Decades of research on the major invertebrate phyla, Mollusca and Arthropoda, have revealed the primary structures and putative functions of several families of structurally related peptides, the best studied being the FMRFamide-related peptides (FaRPs). Recently, the first platyhelminth FaRP was isolated from the tapeworm, Moniezia expansa, and was found to be a hexapeptide amide, GNFFRFamide. Two additional PaRPs were isolated from species of turbellarians; these were pentapeptides, RYIRFamide (Artioposthia triangulata) and GYIRFamide (Dugesia tigrina). The primary structure of a monogenean or digenean FaRP has yet to be deduced. Preliminary physiological studies have shown that both of the turbellarian FaRPs elicit dose-dependent contractions of isolated digenean and turbellarian somatic muscle fibres. Unlike the high structural diversity of FaRPs found in molluscs, arthropods and nematodes, the complement of FaRPs in individual species of platyhelminths appears to be restricted to 1 or 2 related molecules. Much remains to be learnt about platyhelminth PaRPs, particularly from peptide isolation, molecular cloning of precursor proteins, receptor localization, and physiological studies. Copyright (C) 1996 Australian Society for Parasitology.

Individual Differences in Children’s Paths to Arithmetical Development

Cross-sectional and longitudinal data consistently indicate that mathematical difficulties are more prevalent in older than in younger children (e.g. Department of Education, 2011). Children’s trajectories can take a variety of shapes such as linear, flat, curvilinear and uneven, and shape has been found to vary within children and across tasks (J Jordan et al. 2009). There has been an increase in the use of statistical methods which are specifically designed to study development, and this has greatly improved our understanding of children’s mathematical development. However, the effects of many cognitive and social variables (e.g. working memory and verbal ability) on mathematical development are unclear. It is likely that greater consistency between studies will be achieved by adopting a componential approach to study mathematics, rather than treating mathematics as a unitary concept.

Regional Follow up of Late Preterm Neonatal Intensive Care Graduates: Methodological Considerations.

The aim is to guide researchers who are contemplating embarking on research by discussing the methodological challenges encountered in a retrospective follow-up study of three-year-old, late preterm infants (LPIs) who received neonatal intensive care (NIC) in Northern Ireland in 2006. The importance of effective research examining the longer term outcomes of infants admitted to NIC has received increasing recognition. Follow-up cohort and longitudinal studies have grown in number globally, yet the research methodology relating to follow up of NIC graduates is unclear. This paper highlights the methodological challenges of conducting retrospective follow-up research, from the initial planning stages through to the collection of data from the children, including identification of infants from a retrospective database, ethical issues, child-safety concerns and recruitment challenges. This paper creates an awareness of potential issues that may arise in follow-up research with NIC graduates. The paper also offers practical and effective examples of dealing with these issues, helping to ensure the smooth running of an ethical, professionally conducted, methodologically sound and clinically relevant follow-up study.

Advances in joint modelling: A review of recent developments with application to the survival of end stage renal disease patients

The use of joint modelling approaches is becoming increasingly popular when an association exists between survival and longitudinal processes. Widely recognized for their gain in efficiency, joint models also offer a reduction in bias compared with naïve methods. With the increasing popularity comes a constantly expanding literature on joint modelling approaches. The aim of this paper is to give an overview of recent literature relating to joint models, in particular those that focus on the time-to-event survival process. A discussion is provided on the range of survival submodels that have been implemented in a joint modelling framework. A particular focus is given to the recent advancements in software used to build these models. Illustrated through the use of two different real-life data examples that focus on the survival of end-stage renal disease patients, the use of the JM and joineR packages within R are demonstrated. The possible future direction for this field of research is also discussed. © 2013 International Statistical Institute.

Large-Scale Wind Generator Cascaded Tripping

Large scale wind farms are subject to tripping, as a consequence of turbine failure, over-sensitive protection, turbines not equipped with low-voltage ride through (LVRT), and reactive power compensation device defects which can lead to voltage rises. This paper considers pertinent issues which render tripping based on a study of LVRT and wind farm protection, with methods to avoid large scale wind generator tripping proposed. The results of LVRT field tests in Jiuquan, China in December 2012 show that the proposed approaches are effective. The paper also presents work which proposes an early warning system to forecast the risk of wind power tripping.

Surface deformations as a necessary requirement for resistance switching at the surface of SrTiO3:N

Atomic force microscopy (AFM), conductive AFM and electrochemical strain microscopy were used to study the topography change at the defect surface of SrTiO3:N, breakdown in the electrical conduction of the tip/sample/electrode system and ionic motion. The IV curves show resistance switching behavior in a voltage range ±6 V < U <± 10 V and a current of maximum ±10 nA. A series of sweeping IV curves resulted in an increase in ionically polarized states (surface charging), electrochemical volume (surface deformations) and sequential formations of stable surface protrusions. The surface deformations are reversible (U <± 5 V) without IVpinched hysteresis and remained stable during the resistance switching (U >± 6 V), revealing the additional necessity (albeit insufficient due to 50% yield of working cells) of surface protrusion formation for resistance switching memory.

Type Synthesis of 3-DOF Multi-Mode Translational/Spherical Parallel Mechanisms with Lockable Joints

A 3-DOF (degrees-of-freedom) multi-mode translational/spherical PM (parallel mechanism) with lockable joints is a novel reconfigurable PM. It has both 3-DOF spatial translational operation mode and 3-DOF spherical operation mode. This paper presents an approach to the type synthesis of translational/spherical PMs with lockable joints. Using the proposed approach, several 3-DOF translational/spherical PMs are obtained. It is found that these translational/spherical PMs do not encounter constraint singular configurations and self-motion of sub-chain of a leg during reconfiguration. The approach can also be used for synthesizing other classes of multi-mode PMs with lockable joints, multi-mode PMs with variable kinematic joints, partially decoupled PMs, and reconfigurable PMs with a reconfigurable platform.

Investigation of Aircraft Panel Deformations during Riveting Process

In collaboration with Airbus-UK, the dimensional growth of small panels while being riveted with stiffeners is investigated. The stiffeners have been fastened to the panels with rivets and it has been observed that during this operation the panels expand in the longitudinal and transverse directions. It has been observed that the growth is variable and the challenge is to control the riveting process to minimize this variability. In this investigation, the assembly of the small panels and longitudinal stiffeners has been simulated using low and high fidelity nonlinear finite element models. The models have been validated against a limited set of experimental measurements; it was found that more accurate predictions of the riveting process are achieved using high fidelity explicit finite element models. Furthermore, through a series of numerical simulations and probabilistic analyses, the manufacturing process control parameters that influence panel growth have been identified. Alternative fastening approaches were examined and it was found that dimensional growth can be controlled by changing the design of the dies used for forming the rivets.

Genetic Evidence for a Causal Role of Obesity in Diabetic Kidney Disease

Obesity has been posited as an independent risk factor for diabetic kidney disease (DKD), but establishing causality from observational data is problematic. We aimed to test whether obesity is causally related to DKD using Mendelian randomization, which exploits the random assortment of genes during meiosis. In 6,049 subjects with type 1 diabetes, we used a weighted genetic risk score (GRS) comprised of 32 validated BMI loci as an instrument to test the relationship of BMI with macroalbuminuria, end-stage renal disease (ESRD), or DKD defined as presence of macroalbuminuria or ESRD. We compared these results with cross-sectional and longitudinal observational associations. Longitudinal analysis demonstrated a U-shaped relationship of BMI with development of macroalbuminuria, ESRD, or DKD over time. Cross-sectional observational analysis showed no association with overall DKD, higher odds of macroalbuminuria (for every 1 kg/m(2) higher BMI, odds ratio [OR] 1.05, 95% CI 1.03-1.07, P < 0.001), and lower odds of ESRD (OR 0.95, 95% CI 0.93-0.97, P < 0.001). Mendelian randomization analysis showed a 1 kg/m(2) higher BMI conferring an increased risk in macroalbuminuria (OR 1.28, 95% CI 1.11-1.45, P = 0.001), ESRD (OR 1.43, 95% CI 1.20-1.72, P < 0.001), and DKD (OR 1.33, 95% CI 1.17-1.51, P < 0.001). Our results provide genetic evidence for a causal link between obesity and DKD in type 1 diabetes. As obesity prevalence rises, this finding predicts an increase in DKD prevalence unless intervention should occur.

UK medical graduates’ preparedness for practice (P4P): A multi-site qualitative study

Introduction Previous research has demonstrated mixed findings in terms of graduates’ P4P in terms of their knowledge and skills, and interpersonal, systemic and technological aspects (Monrouxe et al. 2014). Few studies have included diverse stakeholders from multiple sites and employing longitudinal methods. We therefore aimed to understand the extent to which UK medical graduates are prepared for practice as Foundation doctors. Methods Cross-sectional qualitative narrative interview and longitudinal audio-diary (LAD) studies with participants from England, Scotland, Wales and Northern Ireland. Study 1 comprised 27 group and 84 individual interviews (n=185) with participants representing different stakeholders (F1s, fully registered trainees, clinical educators, undergraduate/postgraduate deans/foundation programme directors, other healthcare professionals, employers, policy makers, government representatives, and patient/public representatives). Study 2 comprised LADs with 26 F1s over 4-months. Results Participants found it hard initially to conceptualise the term ‘preparedness for practice’. We identified 2187 personal incident narratives (i.e. stories of P4P experiences) across our data: 506 (23%) were classed as ‘prepared’, 730 (33%) as ‘unprepared’ and 951 (44%) as ‘unspecified’. We identified factors that facilitated (e.g. supportive supervisors/colleagues, opportunities for shadowing) and hindered (e.g. unsupportive or disrespectful colleagues, poor organization, understaffing) transitions into and through the Foundation programme. The LADs suggested that trainees felt more confident and competent over time, but that such development was not always linear as challenging circumstances (e.g. new rotations) sometimes made trainees feel unprepared for situations where they had previously indicated preparedness. Conclusion Our findings add to the existing evidence on medical graduates’ P4P in the UK (e.g. Goldacre et al. 2008; Illing et al. 2013). Our findings support the role of assistantships and supportive supervisors for smoothing transitions from student to F1. Further longitudinal and action research studies are now needed to follow students through their final-year assistantships and into their F2 year.