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1.
Sante Publique ; 35(3): 315-328, 2023 10 17.
Article in French | MEDLINE | ID: mdl-37848378

ABSTRACT

Introduction: In South-Kivu, the health system is underfunded due to numerous constraints. Several initiatives have been tested but are insufficient for increasing and sustaining health financing. Purpose of research: Analyze the health financing system in South-Kivu, through a mapping as well as quantitative and qualitative analysis of health financing mechanisms. Results: The provincial health financing system is fragmented, with poorly coordinated mechanisms and interventions, leading to duplication of health system strengthening activities in addition to the absence of a mechanism for pooling external funding flows. Costs recovery (i.e. user fees) and external supports are the most widely used schemes while the government hardly contributes to the financing of the provincial health system. Mutual health insurance is supposed to improve access to health care, but its coverage is still extremely low. Results-Based Financing and free health care programs, fully financed by external donors, are irregular and insufficiently sustainable. Conclusions: It would be critical to implement a strategic purchasing model that is anchored in local institutions, owned by all stakeholders, and integrating all existing financing mechanisms, which could be supported by a common fund supporting the provincial health system. The "Single Contract" initiative developed to harmonize, pool, and sustain external programs, could be a good basis in this respect. This would involve strengthening policy dialogue, developing an investment case to support resource mobilization and implementing a joint monitoring and evaluation platform for disbursements led by the provincial health authorities.


Introduction: Au Sud-Kivu, en République démocratique du Congo, le système de santé est sous-financé dû à de nombreuses contraintes. Plusieurs initiatives ont été testées mais restent insuffisantes pour augmenter et pérenniser le financement de la santé. But de l'étude: Analyser le système de financement de la santé au Sud-Kivu, par une cartographie et une analyse quantitative et qualitative des mécanismes de financement. Résultats: Le système de financement de la santé de la province est fragmenté, avec des mécanismes et interventions peu coordonnés, suscitant des duplications d'activités d'appui au système de santé, en plus de la quasi-absence de mécanisme de mise en commun des appuis extérieurs. Le recouvrement des coûts et les financements extérieurs sont les mécanismes les plus utilisés alors que l'État contribue très faiblement au financement du système provincial de santé. Les mutuelles de santé sont censées améliorer l'accès aux soins, mais leur taux de couverture reste extrêmement faible. Le financement basé sur les résultats et la gratuité des soins, intégralement compensés par les donateurs extérieurs, sont irréguliers et insuffisamment pérennes. Conclusions: Il serait essentiel d'adopter au Sud-Kivu un modèle d'achat stratégique, ancré dans les institutions locales, approprié par l'ensemble des parties prenantes, qui intègre l'ensemble des mécanismes de financement existants et qui soit appuyé par un fonds commun d'appui au système provincial de santé. L'initiative du Contrat unique développée pour harmoniser, mettre en commun et pérenniser les programmes extérieurs peut servir de base pour élaborer un tel modèle. Ceci impliquerait de renforcer le dialogue politique, d'élaborer un dossier d'investissement pour soutenir la mobilisation des ressources et de créer une plateforme conjointe de suivi et d'évaluation des décaissements, pilotée par les autorités provinciales de santé.


Subject(s)
Delivery of Health Care , Healthcare Financing , Humans , Democratic Republic of the Congo
2.
PLoS One ; 17(5): e0268116, 2022.
Article in English | MEDLINE | ID: mdl-35594293

ABSTRACT

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.


Subject(s)
Poverty , Rural Population , Female , Health Promotion , Health Services Accessibility , Humans , Malawi , Male , Socioeconomic Factors
3.
Nature ; 602(7895): 96-100, 2022 02.
Article in English | MEDLINE | ID: mdl-35046578

ABSTRACT

Flight speed is positively correlated with body size in animals1. However, miniature featherwing beetles can fly at speeds and accelerations of insects three times their size2. Here we show that this performance results from a reduced wing mass and a previously unknown type of wing-motion cycle. Our experiment combines three-dimensional reconstructions of morphology and kinematics in one of the smallest insects, the beetle Paratuposa placentis (body length 395 µm). The flapping bristled wings follow a pronounced figure-of-eight loop that consists of subperpendicular up and down strokes followed by claps at stroke reversals above and below the body. The elytra act as inertial brakes that prevent excessive body oscillation. Computational analyses suggest functional decomposition of the wingbeat cycle into two power half strokes, which produce a large upward force, and two down-dragging recovery half strokes. In contrast to heavier membranous wings, the motion of bristled wings of the same size requires little inertial power. Muscle mechanical power requirements thus remain positive throughout the wingbeat cycle, making elastic energy storage obsolete. These adaptations help to explain how extremely small insects have preserved good aerial performance during miniaturization, one of the factors of their evolutionary success.


Subject(s)
Biomechanical Phenomena , Coleoptera/anatomy & histology , Coleoptera/physiology , Flight, Animal/physiology , Wings, Animal/anatomy & histology , Wings, Animal/physiology , Animals , Coleoptera/ultrastructure , Wings, Animal/ultrastructure
4.
Bioinspir Biomim ; 17(2)2022 01 24.
Article in English | MEDLINE | ID: mdl-34644682

ABSTRACT

Insect wings can undergo significant deformation during flapping motion owing to inertial, elastic and aerodynamic forces. Changes in shape then alter aerodynamic forces, resulting in a fully coupled fluid-structure interaction (FSI) problem. Here, we present detailed three-dimensional FSI simulations of deformable blowfly (Calliphora vomitoria) wings in flapping flight. A wing model is proposed using a multi-parameter mass-spring approach, chosen for its implementation simplicity and computational efficiency. We train the model to reproduce static elasticity measurements by optimizing its parameters using a genetic algorithm with covariance matrix adaptation (CMA-ES). Wing models trained with experimental data are then coupled to a high-performance flow solver run on massively parallel supercomputers. Different features of the modeling approach and the intra-species variability of elastic properties are discussed. We found that individuals with different wing stiffness exhibit similar aerodynamic properties characterized by dimensionless forces and power at the same Reynolds number. We further study the influence of wing flexibility by comparing between the flexible wings and their rigid counterparts. Under equal prescribed kinematic conditions for rigid and flexible wings, wing flexibility improves lift-to-drag ratio as well as lift-to-power ratio and reduces peak force observed during wing rotation.


Subject(s)
Flight, Animal , Wings, Animal , Animals , Biomechanical Phenomena , Elasticity , Humans , Insecta , Models, Biological
5.
J Exp Biol ; 225(1)2022 01 01.
Article in English | MEDLINE | ID: mdl-34904650

ABSTRACT

Wing damage attenuates aerial performance in many flying animals such as birds, bats and insects. Insect wings are especially light in order to reduce inertial power requirements for flight at elevated wing flapping frequencies. There is a continuing debate on the factors causing wing damage in insects, including collisions with objects, mechanical stress during flight activity, and aging. This experimental study addressed the reasons for and significance of wing damage for flight in the house fly Musca domestica. We determined natural wing area loss under two housing conditions and recorded flight activity and flight ability throughout the animals' lifetime. Our data show that in animals with eventually pronounced damage, wing damage occurs on average after 6 h of flight, is sex specific and depends on housing conditions. Statistical tests show that physiological age and flight activity have similar significance as predictors for wing damage. Tests on freely flying flies showed that minimum wing area for active flight is approximately 10-34% below the initial area and requires a left-right wing area asymmetry of less than approximately 25%. Our findings broadly confirm predictions from simple aerodynamic theory based on mean wing velocity and area, and are also consistent with previous wing damage measurements in other insect species.


Subject(s)
Diptera , Flight, Animal , Animals , Biomechanical Phenomena , Diptera/physiology , Female , Flight, Animal/physiology , Insecta , Male , Wings, Animal/physiology
6.
J R Soc Interface ; 18(183): 20210518, 2021 10.
Article in English | MEDLINE | ID: mdl-34665973

ABSTRACT

Insect wings are hybrid structures that are typically composed of veins and solid membranes. In some of the smallest flying insects, however, the wing membrane is replaced by hair-like bristles attached to a solid root. Bristles and membranous wing surfaces coexist in small but not in large insect species. There is no satisfying explanation for this finding as aerodynamic force production is always smaller in bristled than solid wings. This computational study suggests that the diversity of wing structure in small insects results from aerodynamic efficiency rather than from the requirements to produce elevated forces for flight. The tested wings vary from fully membranous to sparsely bristled and were flapped around a wing root with lift- and drag-based wing kinematic patterns and at different Reynolds numbers (Re). The results show that the decrease in aerodynamic efficiency with decreasing surface solidity is significantly smaller at Re = 4 than Re = 57. A replacement of wing membrane by bristles thus causes less change in energetic costs for flight in small compared to large insects. As a consequence, small insects may fly with bristled and solid wing surfaces at similar efficacy, while larger insects must use membranous wings for an efficient production of flight forces. The above findings are significant for the biological fitness and dispersal of insects that fly at elevated energy expenditures.


Subject(s)
Flight, Animal , Models, Biological , Animals , Biomechanical Phenomena , Insecta , Wings, Animal
7.
Sci Rep ; 11(1): 6992, 2021 03 26.
Article in English | MEDLINE | ID: mdl-33772058

ABSTRACT

Flapping flight is one of the most costly forms of locomotion in animals. To limit energetic expenditures, flying insects thus developed multiple strategies. An effective mechanism to reduce flight power expenditures is the harvesting of kinetic energy from motion of the surrounding air. We here show an unusual mechanism of energy harvesting in an insect that recaptures the rotational energy of air vortices. The mechanism requires pronounced chordwise wing bending during which the wing surface momentary traps the vortex and transfers its kinetic energy to the wing within less than a millisecond. Numerical and robotic controls show that the decrease in vortex strength is minimal without the nearby wing surface. The measured energy recycling might slightly reduce the power requirements needed for body weight support in flight, lowering the flight costs in animals flying at elevated power demands. An increase in flight efficiency improves flight during aversive manoeuvring in response to predation and long-distance migration, and thus factors that determine the worldwide abundance and distribution of insect populations.


Subject(s)
Air Movements , Biomechanical Phenomena/physiology , Energy Metabolism/physiology , Flight, Animal/physiology , Wings, Animal/physiology , Animals , Drosophila/physiology , Models, Biological
8.
Health Policy Open ; 2: 100043, 2021 Dec.
Article in English | MEDLINE | ID: mdl-37383510

ABSTRACT

Poor vision due to unaddressed refractive error in children is considered to be a public health problem in many low- and middle-income countries. Research shows that correcting refractive error with spectacles could have a positive impact on school attendance and academic performance for children. The aim of this study was to estimate the cost of integrating vision screening and provision of spectacles in existing school health programmes in Cambodia and Ghana. Budget impact analysis of the intervention scale up is also reported, including univariate and multivariate sensitivity analyses. This study suggests that the scale up of school-based vision screening programmes is affordable in resource limited settings, such as Cambodia and Ghana, considering the current education budgets, and providing there is sufficient in-country capacity to deliver such interventions at scale. The study highlights several policy and programme implications and provides suggestions for minimising costs and maximising efficiencies of vision screening in a school setting. Findings from this analysis can help education planners and international partners to improve their planning and budgeting processes for school-based interventions to improve health and learning outcomes for children in low- and middle-income countries.

9.
Insects ; 11(8)2020 Jul 23.
Article in English | MEDLINE | ID: mdl-32718051

ABSTRACT

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.

10.
Ophthalmic Epidemiol ; 27(6): 429-437, 2020 12.
Article in English | MEDLINE | ID: mdl-32449411

ABSTRACT

PURPOSE: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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.


Subject(s)
Cataract Extraction , Cataract , Vision, Low , Blindness , Cross-Sectional Studies , Economic Status , Female , Humans , India , Pakistan , Prevalence , Tanzania
11.
J R Soc Interface ; 17(164): 20190804, 2020 03.
Article in English | MEDLINE | ID: mdl-32156185

ABSTRACT

The aerial performance of flying insects ultimately depends on how flapping wings interact with the surrounding air. It has previously been suggested that the wing's three-dimensional camber and corrugation help to stiffen the wing against aerodynamic and inertial loading during flapping motion. Their contribution to aerodynamic force production, however, is under debate. Here, we investigated the potential benefit of three-dimensional wing shape in three different-sized species of flies using models of micro-computed tomography-scanned natural wings and models in which we removed either the wing's camber, corrugation, or both properties. Forces and aerodynamic power requirements during root flapping were derived from three-dimensional computational fluid dynamics modelling. Our data show that three-dimensional camber has no benefit for lift production and attenuates Rankine-Froude flight efficiency by up to approximately 12% compared to a flat wing. Moreover, we did not find evidence for lift-enhancing trapped vortices in corrugation valleys at Reynolds numbers between 137 and 1623. We found, however, that in all tested insect species, aerodynamic pressure distribution during flapping is closely aligned to the wing's venation pattern. Altogether, our study strongly supports the assumption that the wing's three-dimensional structure provides mechanical support against external forces rather than improving lift or saving energetic costs associated with active wing flapping.


Subject(s)
Diptera , Flight, Animal , Animals , Biomechanical Phenomena , Insecta , Models, Biological , Wings, Animal , X-Ray Microtomography
12.
Appl Health Econ Health Policy ; 17(4): 545-554, 2019 08.
Article in English | MEDLINE | ID: mdl-31065885

ABSTRACT

BACKGROUND: Cataract is the leading cause of avoidable blindness globally. It is estimated that 89% of people with visual impairment live in low- and middle-income countries where the cost of cataract surgery represents a major barrier for accessing these services. Developing self-sustaining healthcare programs to cater the unmet demands warrants a better understanding of patients' willingness to pay (WTP) for their services. OBJECTIVES: Using a sample of patients visiting eye care facilities in Dhaka, Bangladesh, we estimate WTP for two different cataract extraction techniques, namely small incision cataract surgery (SICS) and phacoemulsification. METHODS: We used contingent valuation (CV) approach and elicited WTP through double-bounded dichotomous choice experiments. We interviewed 556 randomly selected patients (283 for SICS and 273 for phacoemulsification) from five different eye care hospitals of Dhaka. In this paper, we estimated the mean and marginal WTP using interval regression models. We also compared the estimated WTP and stated demand for cataract surgeries against the prevailing market prices of SICS and phacoemulsification. RESULTS: We found the mean WTP of BDT 7579 (US$93) for SICS and BDT 10,208 (US$126) for phacoemulsification are equivalent to 12 and 16 days of household income, respectively. Household income and assets appeared as the major determinants of WTP for cataract surgeries. However, we did not find any significant association with gender, occupation, and household size among other socioeconomic characteristics. Comparisons between market prices and average WTP suggest it is possible to have a viable market for SICS, but a subsidy-based model for phacoemulsification will be financially challenging because of low WTP and high costs. CONCLUSION: Our findings suggest lower-cost SICS can potentially provide patients access to surgeries to treat cataract conditions. Moreover, price discrimination and cross-subsidization could be a viable strategy to increase the service-uptake as well as ensure financial sustainability.


Subject(s)
Cataract Extraction/economics , Financing, Personal/economics , Bangladesh , Cataract Extraction/methods , Female , Humans , Interviews as Topic , Male , Middle Aged , Qualitative Research
13.
Biol Open ; 8(1)2019 Jan 14.
Article in English | MEDLINE | ID: mdl-30642916

ABSTRACT

Mechanical properties of insect wings are essential for insect flight aerodynamics. During wing flapping, wings may undergo tremendous deformations, depending on the wings' spatial stiffness distribution. We here show an experimental evaluation of wing stiffness in three species of flies using a micro-force probe and an imaging method for wing surface reconstruction. Vertical deflection in response to point loads at 11 characteristic points on the wing surface reveals that average spring stiffness of bending lines between wing hinge and point loads varies ∼77-fold in small fruit flies and up to ∼28-fold in large blowflies. The latter result suggests that local wing deformation depends to a considerable degree on how inertial and aerodynamic forces are distributed on the wing surface during wing flapping. Stiffness increases with an increasing body mass, amounting to ∼0.6 Nm-1 in fruit flies, ∼0.7 Nm-1 in house flies and ∼2.6 Nm-1 in blowflies for bending lines, running from the wing base to areas near the center of aerodynamic pressure. Wings of house flies have a ∼1.4-fold anisotropy in mean stiffness for ventral versus dorsal loading, while anisotropy is absent in fruit flies and blowflies. We present two numerical methods for calculation of local surface deformation based on surface symmetry and wing curvature. These data demonstrate spatial deformation patterns under load and highlight how veins subdivide wings into functional areas. Our results on wings of living animals differ from previous experiments on detached, desiccated wings and help to construct more realistic mechanical models for testing the aerodynamic consequences of specific wing deformations.

14.
PLoS Negl Trop Dis ; 11(10): e0006023, 2017 Oct.
Article in English | MEDLINE | ID: mdl-29045419

ABSTRACT

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.


Subject(s)
Communicable Disease Control/economics , Epidemiological Monitoring , Health Care Costs , Topography, Medical , Trachoma/epidemiology , Humans
16.
Sci Rep ; 6: 35043, 2016 10 18.
Article in English | MEDLINE | ID: mdl-27752047

ABSTRACT

The natural wind environment that volant insects encounter is unsteady and highly complex, posing significant flight-control and stability challenges. It is critical to understand the strategies insects employ to safely navigate in natural environments. We combined experiments on free flying bumblebees with high-fidelity numerical simulations and lower-order modeling to identify the mechanics that mediate insect flight in unsteady winds. We trained bumblebees to fly upwind towards an artificial flower in a wind tunnel under steady wind and in a von Kármán street formed in the wake of a cylinder. Analysis revealed that at lower frequencies in both steady and unsteady winds the bees mediated lateral movement with body roll - typical casting motion. Numerical simulations of a bumblebee in similar conditions permitted the separation of the passive and active components of the flight trajectories. Consequently, we derived simple mathematical models that describe these two motion components. Comparison between the free-flying live and modeled bees revealed a novel mechanism that enables bees to passively ride out high-frequency perturbations while performing active maneuvers at lower frequencies. The capacity of maintaining stability by combining passive and active modes at different timescales provides a viable means for animals and machines to tackle the challenges posed by complex airflows.


Subject(s)
Bees/physiology , Flight, Animal , Air Movements , Animals , Biomechanical Phenomena , Models, Theoretical , Orientation, Spatial , Wind
17.
PLoS One ; 11(3): e0152072, 2016.
Article in English | MEDLINE | ID: mdl-27019208

ABSTRACT

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.


Subject(s)
Flight, Animal/physiology , Insecta/physiology , Animals , Biomechanical Phenomena , Models, Biological , Wings, Animal/physiology
18.
PLoS One ; 9(2): e89271, 2014.
Article in English | MEDLINE | ID: mdl-24586649

ABSTRACT

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.


Subject(s)
Stroke/epidemiology , Adolescent , Adult , Aged , Female , Humans , Logistic Models , Male , Middle Aged , Morocco/epidemiology , Social Class , Surveys and Questionnaires , Young Adult
19.
Urol Int ; 92(2): 237-41, 2014.
Article in English | MEDLINE | ID: mdl-24051578

ABSTRACT

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.


Subject(s)
Urinary Diversion/methods , Urinary Incontinence/surgery , Urodynamics , Adolescent , Adult , Aged , Cohort Studies , Female , Humans , Male , Middle Aged , Pilot Projects , Pressure , Retrospective Studies , Treatment Outcome , Urinary Bladder/surgery , Urinary Incontinence/diagnosis
20.
Mol Cell Proteomics ; 12(9): 2551-67, 2013 Sep.
Article in English | MEDLINE | ID: mdl-23754785

ABSTRACT

The formation of the immunological synapse between T cells and antigen-presenting cells (APC) begins within minutes of contact and can take hours for full T-cell activation. Although early phases of the synapse have been extensively studied for a select number of proteins, later phases have not yet been examined in detail. We studied the signaling network in stable synapses by measuring the simultaneous localization of 25 signaling and structural molecules over 2 h at the level of individual synapses using multi-epitope ligand cartography (MELC). Signaling proteins including phospho(p)ZAP70, pSLP76, pCD3ζ, and pLAT, along with proteins that influence synapse structure such as F-actin, tubulin, CD45, and ICAM-1, were localized in images of synapses and revealed the multidimensional construction of a mature synapse. The construction of the stable synapse included intense early TCR signaling, a phase of recruitment of structural proteins, and a sustained increase in signaling molecules and colocalization of TCR and pLAT signaling clusters in the center of the synapse. Consolidation of TCR and associated proteins resulted in formation of a small number of discrete synaptic microclusters. Development of synapses and cSMAC composition was greatly affected by the absence of Vav1, with an associated loss in PLCγ1 recruitment, pSLP76, and increased CXCR4. Together, these data demonstrate the use of multi-epitope ligand cartography to quantitatively analyze synapse formation and reveal successive recruitment of structural and signaling proteins and sustained phosphorylation at the mature synapse.


Subject(s)
Immunological Synapses/metabolism , Signal Transduction/immunology , Animals , Chickens , Cluster Analysis , Epitope Mapping , Epitopes/metabolism , Kinetics , Mice , Mice, Inbred C57BL , Mice, Transgenic , Proto-Oncogene Proteins c-vav/deficiency , Proto-Oncogene Proteins c-vav/metabolism , Receptors, Antigen, T-Cell/metabolism , T-Lymphocytes/metabolism
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