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The state-of-the-art of insect flight research using advanced computational fluid dynamics techniques on supercomputers is reviewed, focusing mostly on the work of the present authors. We present a brief historical overview, discuss numerical challenges and introduce the governing model equations. Two open source codes, one based on Fourier, the other based on wavelet representation, are succinctly presented and a mass-spring flexible wing model is described. Various illustrations of numerical simulations of flapping insects at low, intermediate and high Reynolds numbers are presented. The role of flexible wings, data-driven modeling and fluid–structure interaction issues are likewise discussed.

This document provides a list of references to scientific articles and documents that explore various aspects of epoxy thermoset resins. The articles cover topics such as the curing behavior of thermosets, the dynamics of nanoparticles within polymer melts, the nanostructural heterogeneity of epoxy networks, and the effects of temperature on the fracture properties of epoxy systems. The articles utilize techniques such as X-ray photon correlation spectroscopy and molecular dynamics simulations to investigate the behavior and properties of epoxy resins. These resources offer valuable insights for researchers studying epoxy materials. [Extracted from the article]

Introduction: Equity in the access and use of health services is critical if countries are to make progress towards universal health coverage and address the systematic exclusion of the most vulnerable groups. The purpose of this study was to assess if the Co-ordinated Approach To Community Health programme implemented by Sightsavers was successful in reaching the poorest population, women, and people living with disabilities in Kasungu district, Malawi. Methods: Between April and September 2017, data on socio-economic status, household characteristics and functional disability were collected from patients attending at eye camps in Kasungu district, Malawi. Using asset-based tools to measure household wealth (EquityTool© and Simple Poverty Scorecard©) and the Washington Group Short Set of Questions, individuals were categorised by wealth quintiles, poverty status, and functional disability status and then compared to relevant representative national household surveys. In addition, a follow-up household survey was conducted to check the validity of self-reported household characteristics at eye camps. Results: A total of 1,358 individuals participated in the study. The study shows that self-reported data on household characteristics and assets are reliable and can be collected in clinical settings (instead of relying on direct observations of assets). Individuals attending outreach camps were poorer in terms of relative wealth and absolute poverty rates compared to the rest of the population in Kasungu. It was estimated that 9% of the participants belonged to the poorest quintile compared to 4% for the population in Kasungu (DHS 2015–2016). The ultra-poverty rate was also lower among respondents (13%) compared to 15% for Kasungu district (IHS 2017). The functional disability rate was 27.5% for study participants, and statistically higher than the general population (5.6%, SENTIF 2017). Even though women are more at risks than men, 54% of the participants were men. Conclusions: Our study shows that existing tools can be reliably used, and combined, if based on recent population data, to assess equity of access to health services for vulnerable groups of the population. The findings suggest that the programme was successful in reaching the poorest people of the Kasungu district population as well as those with disabilities through outreach camps but that more men than women were reach through the programme. Subsequently, our study showed that self-reported household characteristics are a reliable method to measure asset-based wealth of camps' attendee. However, it is essential to use sub-national data (district or regional level) from recent surveys for the purpose of benchmarking in order to produce accurate results. [ABSTRACT FROM AUTHOR]

The design of new electrically debondable adhesives has been an area of enormous interest for the recycling, repair, and reuse of electrical components for the last decade. However, the complexity of analyzing the debonding process under real conditions is a major obstacle for elucidating the mechanism. Here, a general mechanism for the electrical debonding of ionic acrylic adhesives based on imidazolium ionic liquids is reported. Using synchrotron‐based characterization techniques, in situ experiments mimicking real debonding conditions allowed for the first time the recording of ionic diffusion and chemical reactions during the debonding process. Diffusion of ionic species toward the electrodes triggers the debonding via electrochemical reactions at the adhesive–substrate interfaces. The selection of ionic adhesive chemistry and electrodelamination conditions will eventually determine the type of adhesive failure. A detailed understanding of the mechanism allows the development of new electrically debondable adhesives, which is crucial to promote circular economy and a more sustainable environment. [ABSTRACT FROM AUTHOR]

Prevalence of visual impairment (VI) and access to services can vary significantly across and between different population groups. With renewed focus on universal health coverage and leaving no one behind, it is important to understand factors driving inequitable eye health. This paper presents results from five population-based surveys where prevalence of VI and cataract surgical coverage (CSC) were measured and examined for differences by sex, economic-status, and disability. Rapid assessments of avoidable blindness took place in four rural sites: Kalahandi, Jhabua and Sitapur in India; and Singida, Tanzania; and one urban site: Lahore, Pakistan. In addition, the Equity Tool was used to measure economic status and the Washington Group Short Set was used to measure disability. Prevalence of VI and CSC were calculated and associations with sex, disability, and relative wealth examined. Prevalence of VI varied from 1.9% in Lahore to 15.0% in Kalahandi. CSC varied from 39.1% in Singida to 84.0% in Lahore. Additional disability was associated with greater levels of VI in all sites and lower CSC in Singida. Being female was associated with higher VI in Kalahandi, Lahore and Singida and lower CSC in Lahore and Singida. Being poorer was associated with higher VI in Singida and lower CSC in Singida and Sitapur. Relationships between VI and relative wealth, sex, and disability are complex and variable. Although certain characteristics may be associated with lower coverage or worse outcomes, they cannot be generalized and local data are vital to tailor services to achieve good coverage. [ABSTRACT FROM AUTHOR]

Background: The Global Trachoma Mapping Project (GTMP) was implemented with the aim of completing the baseline map of trachoma globally. Over 2.6 million people were examined in 1,546 districts across 29 countries between December 2012 and January 2016. The aim of the analysis was to estimate the unit cost and to identify the key cost drivers of trachoma prevalence surveys conducted as part of GTMP. Methodology and principal findings: In-country and global support costs were obtained using GTMP financial records. In-country expenditure was analysed for 1,164 districts across 17 countries. The mean survey cost was $13,113 per district [median: $11,675; IQR = $8,365-$14,618], $17,566 per evaluation unit [median: $15,839; IQR = $10,773-$19,915], $692 per cluster [median: $625; IQR = $452-$847] and $6.0 per person screened [median: $4.9; IQR = $3.7-$7.9]. Survey unit costs varied substantially across settings, and were driven by parameters such as geographic location, demographic characteristics, seasonal effects, and local operational constraints. Analysis by activities showed that fieldwork constituted the largest share of in-country survey costs (74%), followed by training of survey teams (11%). The main drivers of in-country survey costs were personnel (49%) and transportation (44%). Global support expenditure for all surveyed districts amounted to $5.1m, which included grant management, epidemiological support, and data stewardship. Conclusion: This study provides the most extensive analysis of the cost of conducting trachoma prevalence surveys to date. The findings can aid planning and budgeting for future trachoma surveys required to measure the impact of trachoma elimination activities. Furthermore, the results of this study can also be used as a cost basis for other disease mapping programmes, where disease or context-specific survey cost data are not available. [ABSTRACT FROM AUTHOR]

We introduce FluSI, a fully parallel open source software package for pseudospectral simulations of three-dimensional flapping flight in viscous flows. It is freely available for noncommercial use from GitHub (https://github.com/pseudospectators/FLUSI). The computational framework runs on high performance computers with distributed memory architectures. The discretization of the three-dimensional incompressible Navier-Stokes equations is based on a Fourier pseudospectral method with adaptive time stepping. The complex time varying geometry of insects with rigid flapping wings is handled using the volume penalization method. The modules characterizing the insect geometry, flight mechanics, and wing kinematics are described. Validation tests for different benchmarks illustrate the efficiency and precision of the approach. Finally, computations for a model insect in the turbulent regime demonstrate the versatility of the software. [ABSTRACT FROM AUTHOR]

Aerodynamic ground effect in flapping-wing insect flight is of importance to comparative morphologies and of interest to the micro-air-vehicle (MAV) community. Recent studies, however, show apparently contradictory results of either some significant extra lift or power savings, or zero ground effect. Here we present a numerical study of fruitfly sized insect takeoff with a specific focus on the significance of leg thrust and wing kinematics. Flapping-wing takeoff is studied using numerical modelling and high performance computing. The aerodynamic forces are calculated using a three-dimensional Navier–Stokes solver based on a pseudo-spectral method with volume penalization. It is coupled with a flight dynamics solver that accounts for the body weight, inertia and the leg thrust, while only having two degrees of freedom: the vertical and the longitudinal horizontal displacement. The natural voluntary takeoff of a fruitfly is considered as reference. The parameters of the model are then varied to explore possible effects of interaction between the flapping-wing model and the ground plane. These modified takeoffs include cases with decreased leg thrust parameter, and/or with periodic wing kinematics, constant body pitch angle. The results show that the ground effect during natural voluntary takeoff is negligible. In the modified takeoffs, when the rate of climb is slow, the difference in the aerodynamic forces due to the interaction with the ground is up to 6%. Surprisingly, depending on the kinematics, the difference is either positive or negative, in contrast to the intuition based on the helicopter theory, which suggests positive excess lift. This effect is attributed to unsteady wing-wake interactions. A similar effect is found during hovering. [ABSTRACT FROM AUTHOR]

Background: Stroke is a growing public health concern in low- and middle- income countries. Improved knowledge about the association between socioeconomic status and stroke in these countries would enable the development of effective stroke prevention and management strategies. This study presents the association between socioeconomic status and the prevalence of stroke in Morocco, a lower middle-income country. Methods: Data on the prevalence of stroke and stroke-related risk factors were collected during a large population-based survey. The diagnosis of stroke in surviving patients was confirmed by neurologists while health, demographic, and socioeconomic characteristics of households were collected using structured questionnaires. We used Multiple Correspondence Analysis to develop a wealth index based on characteristics of the household dwelling as well as ownership of selected assets. We used logistic regressions controlling for multiple variables to assess the statistical association between socioeconomic status and stroke. Findings: Our results showed a significant association between household socioeconomic status and the prevalence of stroke. This relationship was non-linear, with individuals from both the poorest (mainly rural) and richest (mainly urban) households having a lower prevalence of stroke as compared to individuals with medium wealth level. The latter belonged mainly to urban households with a lower socioeconomic status. When taking into account the urban population only, we observed that a third of poorest households experienced a significantly higher prevalence of stroke compared to the richest third (OR = 2.06; CI 95%: 1.09; 3.89). Conclusion: We conclude that individuals from the most deprived urban households bear a higher risk of stroke than the rest of the population in Morocco. This result can be explained to a certain extent by the higher presence of behavioral risk factors in this specific category of the population, which leads in turn to metabolic and physiological risk factors of stroke, such as obesity, diabetes, and hypertension. [ABSTRACT FROM AUTHOR]

Introduction: To evaluate the meaning of urodynamic parameters in patients with pouch incontinence. Materials and Methods: Thirteen urodynamic studies in patients with an ileal nipple as the efferent segment of an ileocecal pouch or ileum/ileocecal-augmented bladder were performed. The recorded parameters included pouch capacity, leak point pressure/volume, maximum pouch pressure, compliance, static and dynamic closure pressure, and functional length. Three patients suffered from urinary incontinence. Results: In all cases of incontinent patients, no functional length or static or dynamic closure pressure could be revealed. In 8 of 10 cases of continent patients, a positive functional length as well as static and/or dynamic closure pressure were measured (mean value in continent patients: 15.9 mm, 14.5 cm H2O and 26.5 cm H2O, respectively). In 2 of 3 cases of incontinent patients, the pouch compliance was restricted (21 and 37 ml/cm H2O). The pouch capacity of continent patients was greater than the capacity of incontinent patients (377.4 vs. 185.7 ml). Conclusions: Positive functional length, static and dynamic closure pressures, and a high pouch capacity with an unrestricted compliance are predictive for pouch continence. They may individually not determine continence, but combining them can. However, the meaning of urodynamic studies in pouch incontinence is not the same as with the urinary bladder. © 2013 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Abstract: We present a new numerical scheme for the simulation of deformable objects immersed in a viscous incompressible fluid. The two-dimensional Navier–Stokes equations are discretized with an efficient Fourier pseudo-spectral scheme. Using the volume penalization method arbitrary inflow conditions can be enforced, together with the no-slip conditions at the boundary of the immersed flexible object. With respect to Kolomenskiy and Schneider (2009) [1], where rigid moving obstacles have been considered, the present work extends the volume penalization method to account for moving deformable objects while avoiding numerical oscillations in the hydrodynamic forces. For the solid part, a simple and accurate one-dimensional model, the non-linear beam equation, is employed. The coupling between the fluid and solid parts is realized with a fast explicit staggered scheme. The method is applied to the fluttering instability of a slender structure immersed in a free stream. This coupled non-linear system can enter three distinct states: stability of the initial condition or maintenance of an either periodic or chaotic fluttering motion. We present a detailed parameter study for different Reynolds numbers and reduced free-stream velocities. The dynamics of the transition from a periodic to a chaotic state is investigated. The results are compared with those obtained by an inviscid vortex shedding method [2] and by a viscous linear stability analysis [3], yielding for both satisfactory agreement. New results concerning the transition to chaos are presented. [Copyright &y& Elsevier]

The shape and function of insect wings tremendously vary between insect species. This review is engaged in how wing design determines the aerodynamic mechanisms with which wings produce an air momentum for body weight support and flight control. We work out the tradeoffs associated with aerodynamic key parameters such as vortex development and lift production, and link the various components of wing structure to flight power requirements and propulsion efficiency. A comparison between rectangular, ideal-shaped and natural-shaped wings shows the benefits and detriments of various wing shapes for gliding and flapping flight. The review expands on the function of three-dimensional wing structure, on the specific role of wing corrugation for vortex trapping and lift enhancement, and on the aerodynamic significance of wing flexibility for flight and body posture control. The presented comparison is mainly concerned with wings of flies because these animals serve as model systems for both sensorimotor integration and aerial propulsion in several areas of biology and engineering. [ABSTRACT FROM AUTHOR]

Fliegende Tiere im Allgemeinen und insbesondere Insekten schlagen mit den Flügeln, um ihren Vor- und Auftrieb zu erzeugen. Landläufiger Meinung zum Trotz können Hummeln erstaunlich gut fliegen. Mit Hilfe der bisher aufwändigsten Computersimulationen haben wir zeigen können, dass die aerodynamischen Mechanismen des Schlagfluges auch dann noch funktionieren, wenn das Insekt in starke Turbulenz gerät. [ABSTRACT FROM AUTHOR]