Myoelectric manifestation of muscle fatigue in repetitive work detected by means of miniaturized sEMG sensors

Upper limb work-related musculoskeletal disorders have a 12-month prevalence ranging from 12 to 41% worldwide and can be partly caused by handling low loads at high frequency. The association between the myoelectric manifestation of elbow flexor muscle fatigue and occupational physical demand has never been investigated. It was hypothesized that an elbow flexor muscle fatigue index could be a valid risk indicator in handling low loads at high frequency. This study aims to measure the myoelectric manifestation of muscle fatigue of the three elbow flexor muscles during the execution of the work tasks in different risk conditions. Fifteen right-handed healthy adults were screened using a movement analysis laboratory consisting of optoelectronic, dynamometer and surface electromyographic systems. The main result indicates that the fatigue index calculated from the brachioradialis is sensitive to the interaction among risk classes, session and gender, and above all it is sensitive to the risk classes.     

Transdermal alcohol monitoring combined with contingency management for driving while impaired offenders: A pilot randomized controlled study

Objectives: In a pilot randomized controlled trial of contingency management (CM) and transdermal alcohol monitoring (TAM) with offenders driving while impaired by alcohol (DWI), perceptions regarding the acceptability of a TAM device, recruitment issues, and the impact of CM and TAM on alcohol use over a 6-week period were evaluated. The results aimed to inform the design of future trials and programs involving CM and TAM for DWI remediation.

Methods: TAM devices were affixed to 37 voluntary, community-recruited male DWI offenders with problem alcohol use. They were randomized to one of 3 groups: (1) CM; (2) alcohol use feedback (FB); and (3) TAM device only (CTL). Quantitative and qualitative data were gathered on the acceptability of TAM devices and recruitment, and alcohol use was monitored via TAM and self-report.

Results: The TAM device was perceived positively, with benefits for reducing drinking noted. Nevertheless, some of its inconveniences appeared to influence participant recruitment and attrition, including its large size and limited water resistance. TAM data revealed a significant main effect of time for reduction in weekly peak transdermal alcohol concentration (P = .02), with a decrease between means of weeks 1 and 6 (M = 0.15, SE = 0.02 vs. M = 0.09, SE = 0.02; P = .005). No significant group effect was detected.

Conclusions: TAM is a viable adjunct to CM with DWI offenders, though the TAM device used here may influence both study recruitment and adherence. These findings can guide the design of future studies into CM and TAM for DWI remediation.     

Could alternative energy sources in the transport sector decarbonise the economy without compromising economic growth?

There are numerous challenges that evaluators face when determining the success of urban climate resilience initiatives (e.g., how to attribute impacts to initiatives). Fortunately, a growing body of literature—much of it dealing with climate change adaptation—has emerged which can help address these challenges. This narrative review of academic and grey literature reviews various monitoring and evaluation methods that can assess the inputs, processes, outputs, outcomes, and impacts that result from climate resilience planning and action. Since there is no commonly accepted monitoring and evaluation approach, the literature stresses the importance of acknowledging the context in which resilience is being evaluated, in order to ensure that appropriate methods are chosen. This context includes the ways that the resilience framework and definition chosen for a project constrain and determine the monitoring and evaluation approaches which can be adopted. As a result of this, a blend of quantitative and qualitative approaches is often recommended, with sufficient evidence suggesting that qualitative approaches (e.g., outcome harvesting) are essential. Nuanced approaches to monitoring and evaluation give evaluators additional means of reporting progress, and of demonstrating success, which is especially important as cities begin to implement resilience initiatives in the coming years.     

Effects of glyphosate on the non-target leaf beetle Cerotoma arcuata (Coleoptera: Chrysomelidae) in field and laboratory conditions

This study aimed to assess the glyphosate application effects on the Cerotoma arcuata Oliver (Coleoptera: Chrysomelidae) population in glyphosate-resistant soybean crops. Field studies were conducted with glyphosate and the insecticide endosulfan to observe the effects of these pesticides on C. arcuata, on its damages in the crop and on the populations of natural enemies in glyphosate-resistant soybean crops. Moreover, the lethal and behavioral sublethal response of C. arcuata to glyphosate and endosulfan was conducted in the laboratory. The results of the field and laboratory experiments showed that glyphosate caused moderate toxicity and high irritability in C. arcuata and that endosulfan caused high toxicity and irritability. Therefore, the direct effect of glyphosate on C. arcuata was negative and does not explain the population increases of this pest in glyphosate-resistant soybean. However, the glyphosate also decreased the density of predators. Thus, the negative effect of glyphosate on the predators may be related to population increases of C. arcuata in glyphosate-resistant soybean crops, however, more studies are needed to better evidence this relationship. This study suggests that glyphosate can impact other non-target organisms, such as herbivorous insects and natural enemies and that the use of this herbicide will need to be carefully stewarded to prevent potential disturbances in beneficial insect communities in agricultural systems.     

Energy crops on landfills: functional,environmental, and costs analysis of different landfill configurations

The cultivation of energy crops on landfills represents an important challenge for the near future, as the possibility to use devalued sites for energy production is very attractive. In this study, four scenarios have been assessed and compared with respect to a reference case defined for northern Italy. The scenarios were defined taking into consideration current energy crops issues. In particular, the first three scenarios were based on energy maximisation, phytotreatment ability, and environmental impact, respectively. The fourth scenario was a combination of these characteristics emphasised by the previous scenarios. A multi-criteria analysis, based on economic, energetic, and environmental aspects, was performed. From the analysis, the best scenario resulted to be the fourth, with its ability to pursue several objectives simultaneously and obtain the best score relatively to both environmental and energetic criteria. On the contrary, the economic criterion emerges as weak, as all the considered scenarios showed some limits from this point of view. Important indications for future designs can be derived. The decrease of leachate production due to the presence of energy crops on the top cover, which enhances evapotranspiration, represents a favourable but critical aspect in the definition of the results.     

Speciation and quantification of Hg in sediments contaminated by artisanal gold mining in the Gualaxo do Norte River,Minas Gerais,SE, Brazil

The Iron Quadrangle in SE Brazil was, in the eighteenth century, one of the most important Au producing regions of Brazil. In this region, gold is produced, even today, by artisanal methods that use Hg to increase the extraction efficiency with no control of Hg release to water systems and the atmosphere. In this context, the Gualaxo do Norte River is of particular interest; its springs are located in the Doce River basin, an important Brazilian basin that supplies water for 3.5 million people. The main goal of this work was to quantify and speciate the Hg in the sediments of the Gualaxo do Norte River using a direct mercury analyzer and gas chromatography-pyrolysis-atomic fluorescence detection system. Statistical analyses consisted of principal component analysis, aiming to assess interactions among elements and species and to group the variables in factors affecting the properties of sediment. The results show that total Hg (THg) and methylmercury (CH₃Hg⁺) concentrations in samples ranged from 209 to 1207 μg kg^?1 and from 0.07 to 1.00 μg kg^?1, respectively (methylation percentages from 0.01 to 0.27%). Thermal desorption analysis showed that mercury is mainly present in the oxidized form, and correlation analyses pointed to a relationship between THg and MnO, indicating that manganese can oxidize and/or adsorb Hg. Together, MO and CH₃Hg⁺ are important parameters in the third principal component, indicating the influence of OM on the methylation process. This first investigation on Hg methylation in this small-scale gold mining area points to the possibility of Hg bioaccumulation and to the need of better understanding the biogeochemical cycle of Hg in this area. Samples were collected in 2012, prior to the 2015 Fundão Dam disaster. The results are also a record of the characteristics of the sediment prior to that event.     

160 h of chemical-looping combustion in a 10 kW reactor system with a NiO-based oxygen carrier

Chemical-looping combustion, CLC, is a technology with inherent separation of the greenhouse gas CO₂. The technique uses an oxygen carrier made up of particulate metal oxide to transfer oxygen from combustion air to fuel. In this work, an oxygen carrier consisting of 60% NiO and 40% NiAl₂O₄ was used in a 10 kW CLC reactor system for 160 h of operation with fuel. The first 3 h of fuel operation excepted, the test series was accomplished with the same batch of oxygen carrier particles. The fuel used in the experiments was natural gas, and a fuel conversion to CO₂ of approximately 99% was accomplished. Combustion conditions were very stable during the test period, except for the operation at sub-stoichiometric conditions. It was shown that the methane fraction in the fuel reactor exit gas was dependent upon the rate of solids circulation, with higher circulation leading to more unconverted methane. The carbon monoxide fraction was found to follow the thermodynamical equilibrium for all investigated fuel reactor temperatures, 660–950 °C. Thermal analysis of the fuel reactor at stable conditions enabled calculation of the particle circulation which was found to be approximately 4 kg/s, MW. The loss of fines, i.e. the amount of elutriated oxygen carrier particles with diameter <45 μm, decreased during the entire test period. After 160 h of operation the fractional loss of fines was 0.00022 h⁻¹, corresponding to a particle life time of 4500 h.     

CO2 transportation for carbon capture and storage: Sublimation of carbon dioxide from a dry ice bank

Climate change is being caused by greenhouse gases such as carbon dioxide (CO₂). Carbon capture and storage (CCS) is of interest to the scientific community as one way of achieving significant global reductions of atmospheric CO₂ emissions in the medium term. CO₂ would be captured from large stationary sources such as power plants and transported via pipelines under high pressure conditions to underground storage. If a downward leakage from a surface transportation system module occurs, the CO₂ would undergo a large temperature reduction and form a bank of “dry ice” on the ground surface; the sublimation of the gas from this bank represents an area source term for subsequent atmospheric dispersion, with an emission rate dependent on the energy balance at the bank surface. Gaseous CO₂ is denser than air and tends to remain close to the surface; it is an asphyxiant, a cerebral vasodilator and at high concentrations causes rapid circulatory insufficiency leading to coma and death. Hence a subliming bank of dry ice represents safety hazard. A model is presented for evaluating the energy balance and sublimation rate at the surface of a solid frozen CO₂ bank under different environmental conditions. The results suggest that subliming gas behaves as a proper dense gas (i.e. it remains close to the ground surface) only for low ambient wind speeds.     

Physical and chemical properties of feedlot pen surfaces located on moderately coarse- and moderately fine-textured soils in southern Alberta

Southern Alberta has the highest density of feedlot cattle in Canada, and there is a concern that leaching of water and contaminants may be greater for feedlots located on coarser-textured than finer-textured soils. Our objective was to determine if infiltration and leaching were greater for a 4-yr-old feedlot located on a moderately coarse-textured (MC) soil compared with two feedlots located on moderately fine-textured (MF) soils (5- and 52-yr-old pens). Various soil physical properties of feedlot pen surfaces were measured, including field-saturated hydraulic conductivity (K(fs)) and near-saturated hydraulic conductivity at -0.9 and -3.9 cm water potential. Selected chemical properties of feedlot soil layers were measured, as well as the chloride content of the soil profile (0-100 cm). Mean K(fs), K(-0.9), and K(-3.9) values were not significantly (P > 0.10) greater at the MC site than the two MF sites, indicating no evidence of greater infiltration on coarser-textured soils. In addition, mean K(fs), K(-0.9), and K(-3.9) values of soils within feedlot pens at all three sites were significantly (P < or = 0.10) reduced by 46 to 78% compared with soil outside the pens. Depth of chloride accumulation was greatest at the 52-yr-old feedlot on MF soil (60-70 cm), followed by 4-yr-old feedlot on MC soil (40-50 cm) and 5-yr-old feedlot on MF soil (30-40 cm). Visual inspection determined that the black interface layer formed within 2 mo of cattle stocking at all three sites.