Biomechanical Performance Analysis of the Monolateral External Fixation Devices with Steel and Composite Material Frames under the Impact of Axial Load

This paper describes comparative analysis of the biomechanical performances conducted on the external fixation devices whose frames are made out of two different material (stainless steel and composite material). Biomechanical properties were determined with experimental and FEM (finite element method) models which are used to study the movement of the fracture crack, establish stiffness of the design solutions and monitor generated stresses on the zones of interest. Geometric modeling of two fixation devices configurations B50 and C50 is used as a basis for structural analysis under the impact of axial load. Structural analysis results are confirmed with an experimental setup. Analyzed deflection values in the load and fracture zones are used to define the exact values of the stiffness for the construction design and fracture, respectively. The carbon frame device configuration has 28% lower construction stiffness than the one with the steel frame (for B50 configuration), i.e., 9% (for C50 configuration). In addition, fracture stiffness values for the composite frame application are approximately 23% lower (B50 configuration), i.e., 13% lower (C50 configuration), compared to steel frame. The carbon frame device has about 33% lower stresses at the critical zones compared to the steel frame at the control zone MM+ and, similarly, 35% lower stresses at the control zone MM-. With an exhausting analysis of the biomechanical properties of the fixation devices, it can be concluded that steel frame fixation device is superior, meaning it has better biomechanical characteristics compared to carbon frame fixation device, regarding obtained data for stresses and stiffnesses of the frame construction and fracture. Considering stresses at the critical zones of the fixation device construction, the carbon frame device has better biomechanical performances compared to steel frame devices.

Impacts D’une Technique De Restauration De Terre Dégradée Sur La Survie Et La Croissance Des Plants De Quatre Espèces De Combretaceae En Zone Sahélienne Du Niger

Les banquettes sylvopastorales constituent l’une des techniques les plus utilisées au Niger pour restaurer les terres dégradées de plateaux. La présente expérimentation a été réalisée sur un plateau dégradé de Simiri dans l’Ouest nigérien où des banquettes sylvopastorales ont été installées. L’objectif est d’évaluer la survie et la croissance des plants de quatre essences locales de Combretaceae, Combretum glutinosum, Combretum micranthum, Combretum nigricans et Guiera senegalensis. Les méthodes utilisées ont consisté d’abord à délimiter un espace sur le plateau dégradé où 40 banquettes sont confectionnées et un autre espace sans banquette pour servir de témoin. Dans les banquettes, 200 plants de chaque espèce ont été plantés à raison de 20 plants/banquette. Deux mois après la plantation un suivi périodique de l’humidité du sol et des paramètres dendrométriques des plants a été effectué durant 30 mois. Les paramètres dendrométriques mesurés sont le taux de survie, la hauteur et le diamètre au collet du grand axe caulinaire, le nombre de rejets et de feuilles. Les résultats obtenus ont montré d’une part que les banquettes améliorent les conditions hydriques du sol de 18,19 % par rapport à la zone non traitée (sans banquette) et d’autre part que les meilleurs taux de survie et de croissance ont été observés au niveau des espèces Guiera senegalensis, Combretum. glutinosum et Combretum. micranthum. Ainsi, les espèces Guiera senegalensis, Combretum glutinosum et Combretum micranthum peuvent être utilisées dans le reboisement de sites aménagés avec des banquettes sylvopastorales pour restaurer les terres de plateaux au Niger Silvopastoral banquettes are one of the techniques mostly used in Niger to restore degraded plateau lands. The present experiment was carried out on a degraded Simiri plateau in western Niger where silvopastoral banquettes have been installed. The objective is to assess the survival and growth of plants of four local species of Combretaceae, Combretum glutinosum, Combretum micranthum, Combretum nigricans, and Guiera senegalensis. The methods used consisted first of delimiting a space on the degraded plateau where 40 banquettes are made and another space without a banquette to serve as a control zone. In the banquettes, 200 plants of each species were planted at 20 plants/banquette. Two months after planting, periodic monitoring of soil moisture and dendrometric parameters of the plants was carried out for 30 months. The dendrometric parameters measured are the survival rate, the height and the collar diameter of the stem axis, the number of suckers and leaves. The results obtained showed on the one hand that the banquettes improve the water conditions of the soil by 18.19% compared to the untreated zone (without banquettes) and on the other hand that the best survival and growth rates were observed at the level of the species Guiera senegalensis, Combretum. glutinosum and Combretum. micranthum. Thus, Guiera senegalensis, Combretum glutinosum, and Combretum micranthum species can be used in the reforestation of sites developed with silvopastoral banquettes to restore plateau lands in Niger.

Satellite-Based Monitoring of Primary Production in a Mediterranean Islet Post Black Rat Eradication

Invasive rodents have a detrimental impact on terrestrial ecosystem functioning, this is often exacerbated on small islands. Rat eradication campaigns are often used to deal with this environmental perturbation given their classification as invasive species. Studies assessing the effects of rodent control at ecosystem scale are scarce and thus little is known about the subsequent functional response of vegetation subsequent to rat control. In this work, we use remote sensing to assess the effects of black rat (Rattus rattus) eradication on Mediterranean vegetation productivity in the Sa Dragonera Islet, Mallorca (Spain). Rats feed on seeds, sprouts, and leaves of woody vegetation and hence we expect primary production to increase nine years after the rodenticide campaign. The Break Detection approach for additive season and trend (BFAST method) was adopted to examine changes in vegetation density before and after the eradication campaign in Sa Dragonera Islet (Balearic Islands), using a temporal series of monthly NDVI data extracted from Landsat imagery. The same temporal trends were examined for a control zone where no rat eradication took place, in order to control for weather-driven changes. The results of this study revealed changes across the 21-year monthly NDVI time series. However, the dates, magnitude, and trend of these changes could not be explicitly attributed to the action of rats, when compared to the historical changes on the islet and the changes found to co-occur within the control zone. These finding could, perhaps, be explained by the high resilience of Mediterranean shrubs to browsing including that of rat invasion. However, the results from the study appear to show that rat damage on specific plant species, with little contribution to global NDVI values, would be overshadowed by the effects of broader environmental factors in this remote sensing approach. The results suggest that the current passive restoration scheme imposed following eradication is not sufficient for effective ecosystem restoration.

Effectiveness and Coverage of Treatment for Severe Acute Malnutrition Delivered by Community Health Workers in the Guidimakha Region, Mauritania

Geographical and economic access barriers to health facilities (HF) have been identified as some of the most important causes of the low coverage of severe acute malnutrition (SAM) treatment. The objective of this study is to assess the effectiveness and coverage of SAM treatment delivered by community health workers (CHWs) in the Guidimakha region in Mauritania, compared to the HF based approach. This study was a nonrandomized controlled trial, including two rural areas. The control group received outpatient treatment for uncomplicated SAM from HF, whilst the intervention group received outpatient treatment for uncomplicated SAM from HF or CHWs. A total of 869 children aged 6–59 months with SAM without medical complications were included in the study. The proportion of cured children was 82.3% in the control group, and 76.4% in the intervention group, we found no significant difference between the groups. Coverage in the intervention zone increased from 53.6% to 71.7%. In contrast, coverage remained at approximately 44% in the control zone from baseline to end-line. This study is the first to demonstrate in Mauritania that the decentralization model of CHWs treating SAM improves acute malnutrition treatment coverage and complies with the international quality standards for community treatment of acute malnutrition. The non-randomized study design may limit the quality of the evidence, but these results could be used by political decision-makers as a first step in revising the protocol for acute malnutrition management.

New Algorithm for Upgrading of Portal Radiation Monitors with Plastic Detectors. Part 3. Description of the Algorithm

New algorithm is described in the third part of the paper. It uses method of energy windows and is based on iterative scheme. Values of smoothing and thresholds are optimized in each energy window and time step during of movement of transport through control zone. Some parameters of monitor which are measured on the place of its installation or manufacturing are used as input information.

Modeling the Size of Protection Zones of Cultural Heritage Sites Based on Factors of the Historical and Cultural Assessment of Lands

This article addresses the global issue of preserving cultural heritage, which is associated, among other things, with the lack of provision for boundaries of protection zones for cultural heritage sites. This paper analyzes the worldwide experience in the field of establishing protection zones for cultural heritage sites, identifies the issues of preserving cultural heritage in Russia, as well as imperfections in the management of lands containing cultural heritage sites. To improve the management of such lands, a method of historical and cultural assessment of territories has been developed, which, on the basis of evaluative factors, makes it possible to characterize the historical and cultural value of a territory. In this article, based on this list of factors, a method for mathematical substantiation of the boundaries of protection zones of cultural heritage sites has been developed; this method includes seven stages. Using mathematical and statistical methods, models were obtained to determine the area of the protection (buffer) zone and the development control zone, the analysis of which revealed differentiation between the factors of historical and cultural assessment that characterize the urban environment, depending on the type of zones. The interpretation of the obtained models and the fields of their use are given.

REGIONAL ECOLOGICALLY DEPENDENT FEATURES OF THE VEGETATIVE STATUS OF THE POPULATION IN LVIV REGION

In recent years, negative demographic phenomena are growing in Lviv region as well as in Ukraine on the whole. They are manifested in falling birth rates, rising mortality, rising morbidity which are inextricably linked with ecological imbalance and environmental degradation in general. The aim of our research was to identify the features of the degree of stress of the adaptation mechanisms, vegetative status and functional health (of population) of “radiation-clean” Lviv region and compare the results with the results of FEE of “radiation-contaminated” Vinnytsia and Chernihiv regions. We examined 1592 children of different ages and sexes living in Lviv region with the help of functional-vegetative diagnostics (FVD) of vegetative health by the method of V.G. Makats, which allows us to identify indicators of variance of vegetative levels that act as integral bioindicators of internal homeostasis. The bioelectrical activity of 12 symmetrical pairs of functionally active zones of the skin (24 PHASES), 12 on arms and 12 on legs, which reflect the functional activity of the sympathetic and parasympathetic nervous systems was studied. Atmospheric air pollution, drinking water quality, waste accumulation are the main factors that harm the health of the population. Emissions of pollutants into the atmosphere from stationary sources of pollution in Lviv region in 2019 were 16.7% less than in 2018. The overall dynamics of pollutant emissions in 2000-2019 was characterized by a downward trend, from 108.6 thousand tons in 2000 to 88.9 thousand tons in 2019. In 2019, 1.0% more waste was generated in Lviv region than in 2018. In 2019, 858 kg of waste was generated per capita in Lviv region, that is 99 tons per 1 km2. The Lviv region is not included in the radiation control zone of Ukraine and is considered to be «conditionally clean». While studying the variance of vegetative levels and, accordingly, the functional health of children in Lviv region in 2001-2006, we found that in female and male groups vegetative dynamics had a «sympathetic orientation» (critical functional stress of adaptation), so the percentage of surveyed children included in the zone of increase of sympathetic activity fluctuated from 36% in 2006 to 64% in 2004 in the female group under supervision and from 36,5% in 2003 to 55,7% in 2006 in male that is much higher than 15%. of the norms. The critical advantage of «sympathetic dispersion» is not ideal for functional health, but in this situation it indicates the absence of a «radiation component» of the integrated environmental pressure. Functional and ecological examination of Lviv region in 2001-2006 revealed its relation to the zone of «functional protection tension». We noted an opposite situation during long-term observations of the dynamics of functional health of children in Vinnytsia and Chernihiv regions which belong to the 4th zone of state radiation control. In addition, the children living in these regions were characterized by the development of persistent parasympathicotonia (vagotonia). While analyzing the state of functional health of children due to the vegetative coefficient (kV), which characterizes the adaptive potential of the population, it was found that at a rate of kV 0.95-1.05, which corresponds to the vegetative balance, in all gender groups and in all years of observation it is at much higher levels. Its average value ranged from 1.15 in 2002 to 1.30 in 2004 and 1.19 was the overall average for all years of observation. Speaking about children living in Lviv region, there are changes that reflect the imbalance of the autonomic nervous system towards the predominance of sympathetic regulation, accompanied by increased energy needs.Prolonged predominance of sympathetic regulation leads to depletion of energy reserves and, as a consequence, can provoke the emergence and development of diseases of various etiologies.

Driving Safety Assurance Method in Work Zone Crossovers of Highway Reconstruction and Expansion Project

Work zone crossover is an important area in highway reconstruction and expansion projects because it profoundly impacts the traffic safety and efficiency of the construction sites. This research sets the different median opening widths in the driving simulation experiment, collects the vehicle control signal parameters during entrance by-pass and exit by-pass, and analyzes the driving characteristics in these sections. Comparison of the driving features between the simulation experiment and the actual driving under the same median width has been also made. We should set the median width separately because the results show that driving behaviors significantly differ between entrance by-pass and exit by-pass. When the median opening width is 70 m, the driving simulation experiment and actual driving characteristics are quite different. However, both show that driving factors of the entrance and exit by-pass are not the same. When there are two lanes in the traffic control zone and the speed limit is 60 km/h, we should set the median width at 90 m to ensure transportation safety.

Effects of Strip Roads in a Pine Tree Stand (Pinus sylvestris L.) on the Diameter Growth and Pith Eccentricity of Trees Growing along Them

Although skid roads are more and more commonly used in Poland, they are still quite often criticised due to a certain loss of wood volume and the impact on edge trees. In this context, the results of the research described in this article can be used as a substantive contribution to discussions about strip roads. Research was carried out in a 42-year-old pine tree stand (Pinus sylvestris L.) in the Notecka Forest, where thinning had been performed and 2.5 and 3.5 m wide strip roads had been cut 10 years before. The analysis comprised two five-year periods recording diameter growth and pith eccentricity in trees growing at the distance zones of 0–1 m (adjacent trees), 2–4 m and 8–10 m (the control) away from the strip roads. The differences in growth and eccentricity between the different distance zones as well as the frequency of pith eccentricity in the N-W, S-W, N-E and S-E directions were assessed, related to the distance from the strip road and the measurement height. The measurements of the analysed traits were conducted on wood discs cut from the centres of two-metre-long sections on sample trees (12 trees in each distance zone). The trees growing directly beside the strip roads were statistically significantly thicker than those growing 8–10 m away, and in the case of the trees beside the narrower strip roads, in the second 5-year period, they were also thicker than the trees from the 2–4 m distance zone. The effect of the wider strip roads in the first growth period was also significant for the trees growing 3 m away from the strip road (their growth in this period was significantly greater than that of trees in the control zone). The research into tree-pith eccentricity showed no differences due to relative distance from the strip road. Furthermore, no statistically significant relationship between the distance of trees from the strip road, measurement height and frequency of tree-pith eccentricity to the N-W and S-W were found.

Epiphytic Cryptogams as Bioindicators of Air Quality in a Tropical Andean City

Air pollution is one of the main environmental problems in developed and developing countries. Epiphytic cryptogams (bryophytes and lichens) are proposed as a reliable indicator to detect environmental changes, given to their sensitivity to pollutants. In this study we evaluated air quality in the city of Ambato using bryophytes and epiphytic lichens on three land uses (urban, peri-urban and control). In each zone we selected ten trees (a total of 90 trees) for each station (a total of nine stations), where we recorded the frequency and cover of epiphytic cryptogams in a quadrat of 10 × 50 cm that was divided into 5 × 5 cm squares. Differences in richness, index of atmospheric purity (IAP) and diversity were analyzed using a generalized linear model (GLM) and changes in species composition using multivariate analysis. We recorded 39 species of cryptogams (25 lichens and 14 bryophytes). Richness, diversity and index of atmospheric purity were higher in the control zone compared to the urbanized zones. Community composition changed between the different zones, with increasing differences between the control and urban zones. The urban areas of the city of Ambato were identified with high levels of air pollution due to their lower diversity related to higher vehicular traffic and industrial activities (e.g., footwear and textile factories, tanneries). Thus, epiphytic cryptogams are a fast and low-cost method for air quality assessment in tropical areas.