The rapid development and increase of antibiotic resistance are global phenomena resulting from the extensive use of antibiotics in human clinics and animal feeding operations. Antibiotics can promote the occurrence of antibiotic resistance genes (ARGs), which can be transferred horizontally to humans and animals through water and the food chain. In this study, the presence and abundance of ARGs in livestock waste was monitored by quantitative PCR. A diverse set of bacteria and tetracycline resistance genes encoding ribosomal protection proteins (RPPs) from three livestock farms and a river were analyzed through denaturing gradient gel electrophoresis (DGGE). The abundance of sul(I) was 103 to 105 orders of magnitude higher than that of sul(II). Among 11 tet-ARGs, the most abundant was tet(O). The results regarding bacterial diversity indicated that the presence of antibiotics might have an evident impact on bacterial diversity at every site, particularly at the investigated swine producer. The effect of livestock waste on the bacterial diversity of soil was stronger than that of water. Furthermore, a sequencing analysis showed that tet(M) exhibited two genotypes, while the other RPPs-encoding genes exhibited at least three genotypes. This study showed that various ARGs and RPPs-encoding genes are particularly widespread among livestock. 相似文献
Objective: The objective of this study is to develop a novel algorithm on a mobile system that can warn drivers about the possibility of a collision with a pedestrian. The constraints of the algorithm are near-real-time detection speed and a good detection rate.
Method: Histogram of gradients (HOG)-based detection is widely used in pedestrian safety applications; however, it has low detection speed for real-time systems. Hence, it has no direct usage for mobile systems. In order to achieve near-real-time detection speed, partial Haar transform predetections are applied to an image before HOG detection. The partial and HOG detections are merged and a score-based confidence level is defined for the final detection phase. In this way, the outcome is prioritized and different warning levels can be issued to warn the driver before a possible pedestrian collision.
Results: The proposed algorithm provides an increase in detection speed (from 46 to 76 fps) and detection rate (from 80 to 91%) with respect to HOG-based pedestrian detection. It also improves confidence of the results by multidetection merging and score assignment to detections.
Conclusions: Performance improvement of the algorithm is compared with respect to state-of-the-art detectors/algorithms. Based on the detection rate and detection speed performance, it can be concluded that the proposed algorithm is suitable to be used for mobile systems to warn drivers about the possibility of collision with a pedestrian. 相似文献
Research on the micro- and macrocharacteristics of different metamorphic degrees of coal helps improve the control and protection techniques used during spontaneous combustion. Nine coals with different properties were thoroughly investigated in this study. Fourier transform infrared spectroscopy and a self-designed temperature-programmed oil bath experimental system were adopted to analyze the molecular structure and macrocharacteristic parameters of the spontaneous combustion of coal. Additionally, the influence of particle size on spontaneous combustion was considered. Various functional groups were employed as microcharacteristic parameters to capture the principal active groups in oxidation. The gas production rate, oxygen consumption rate, gas concentration, heat energy release rate, and characteristic temperatures were evaluated as macrocharacteristic parameters to investigate the changes in coal during oxidation. The results establish that the microcharacteristics of coal molecules determine the degree of spontaneous combustion based on intrinsic properties and that changes in the macrocharacteristics of the spontaneous combustion of coal reflect the microstructural changes. The contents of the hydroxyl groups, carbonyl groups, alkyl ether and aryl ether in the coal molecules gradually decrease with the metamorphic increase. Oxygen-containing functional groups have higher reactivities and easily react with oxygen, causing the macroparameters, such as the oxygen consumption rate, the gas generation rate and the heat energy release rate, to consistently decrease with the increase of the metamorphic degree. Small-particle-size coal molecules have more active aliphatic hydrocarbons, oxygen-containing functional groups and a larger specific surface area, increasing the chances of adsorbing the oxygen of active groups and promoting the reaction between coal and oxygen. The experimental results indicate that coal samples with higher metamorphic degrees or larger sizes exhibit lower tendencies toward spontaneous combustion. Evaluation of the spontaneous combustion of coal based on a temperature-programmed oil bath experimental system is of great practical importance for preventing the spontaneous combustion of coal during storage, processing and utilization and can serve as a convenient reference for production safety in mining applications. 相似文献
Liquefied natural gas (LNG) has been largely indicated as a promising alternative solution for the transportation and storage of natural gas. In the case of accidental release on the ground, a pool fire scenario may occur. Despite the relevance of this accident, due to its likelihood and potential to trigger domino effects, accurate analyses addressing the characterization of pool fires of LNG are still missing.In this work, the fire dynamic simulator (FDS) has been adopted for the evaluation of the effects of the released amount of fuel and its composition (methane, ethane, and propane), on the thermal and chemical properties of small-scale LNG pool fire. More specifically, the heat release rate, the burning rate, the flame height, and thermal radiation, at different initial conditions, have been evaluated for pool having diameter smaller than 10 m. Safety distances have been calculated for all the investigated conditions, as well.Results have also been compared with data and correlations retrieved from the current literature. The equation of Thomas seems to work properly for the definition of the height over diameter ratio of the LNG pool fire for all the mixture and the investigated diameters.The addition of ethane and propane significantly affects the obtained results, especially in terms of radiative thermal radiation peaks, thus indicating the inadequacy of the commonly adopted assumption of pure methane as single, surrogate species for the LNG mixture. 相似文献
Objective: This study examined the risk factors of driving under the influence of alcohol (DUI) among drivers of specific vehicle categories (DSC). On the basis of this research, the variables related to DUI and involvement in traffic crashes were defined. The analysis was conducted for car drivers, bicyclists, motorcyclists, bus drivers, and truck drivers.
Method: The research sample included drivers involved in traffic crashes on the territory of Serbia in 2016 (60,666). Two types of analyses were conducted in this study. Logistic regression established the correlation between DUI and DSC and the The Technique for Order of Preference by Similarity to Ideal Solution (Multi-criteria decision making) method was applied to consider the scoring and explore the potential for the prevalence of DUI on the basis of 2 data sets (DUI and non DUI).
Results: The study results showed that driver error and male drivers were the 2 most significant risk factors for DUI, with the highest scores and potential for prevalence. The nonuse of restraint systems, driver experience, and driver age are the factors with a significant prediction of involvement in an accident and an insignificant prediction of DUI.
Conclusions: Following the development of the logistic prediction models for DUI drivers, testing of the model was conducted for 3 control driver groups: Car, motorcycle, and bicycle. The prediction model with a probability greater than 50% showed that 77% of car drivers were under the influence of alcohol. Similarly, the prediction percentage for motorcyclists and bicyclists amounted to 71 and 67%, respectively. The recommendation of the study is that drivers whose DUI probability is above 50% should be potentially suspected of DUI. The results of this study can help to understand the problem of DUI among specific driver categories and detect DUI drivers, with the aim of creating successful traffic safety policy. 相似文献
ABSTRACTInteraction of environmental pollution between peripheral areas has become a central topic in the field of resources and environment but little is known about the actual impact on peripheral areas in the current literature. This paper sets out a simultaneous equation model to investigate the spillover effect of environmental pollution between China’s peripheral areas utilizing the panel data of 218 cities in China. Making use of indicators for measuring the impact on environmental pollution, it identifies that environmental pollution between cities of China has a significant two-way spillover effect. After standardization of variables, it is found that the spillover effect of peripheral areas on urban environmental pollution cannot be neglected. Nearly, a third of the environmental pollution level in a city is induced by the environmental pollution in peripheral areas. If the indicator of environmental pollution in peripheral areas is missing, wrong conclusions will be drawn. Therefore, government should shift the emphasis of environmental regulation from local to global, and improve the overall environmental quality through coordinated management of regional environment. 相似文献