Scientific Research and Reviews

Zn is one of the main ore-forming elements and has important economic value. However, as a heavy metal element, excessive emission will cause serious environmental pollution. At the same time, Zn is a trace element needed for life activities, which is an important component of a variety of enzymes or coenzymes in organisms, and has great significance for biological life activities. But in high concentrations it becomes toxic and affects the health of the organism. This study is based on the first-principles calculation method of density functional theory (DFT) to accurately quantify Zn isotope balance fractionation during the internal formation of organic matter. The calculated results are as follows: Δ66/64Zn=-0.232~-3.036‰ at 25 0C. The more N and S atoms present in the donor atom, the greater the equilibrium fractionation and the greater the enrichment of lighter Zn isotopes.

With the rapid development of social economy, people’s life on the increasing demand for water resources, surface water resources have been unable to meet the needs of human, and groundwater has stable water supply capacity and good water quality, so the development of groundwater resources has become a topic of concern from all walks of life. If we fail to pay attention to the rationality and appropriateness of resource development, it will inevitably cause certain environmental pollution. This paper first expounded the ecological and environmental problems caused by the overexploitation of groundwater resources, and then put forward reasonable solutions, hoping to help people to rationally use and protect groundwater resources.

Mine water damage is a major threat to the safe production of coal mines in China, and how to predict mine water surges scientifically and effectively is an important basis for mine water damage accident prevention and protection of groundwater resources. This paper takes a mine field in northwest China as the research object, comprehensively grasps the geological and hydrogeological conditions of the mine and analyses the causes of coal seam water filling; applies Visual MODFLOW to establish a numerical model of groundwater flow in the study area, and carries out dynamic prediction of mine water influx under natural and artificial boundary conditions respectively based on the method of water conservation and coal mining. The results show that the water influx is significantly reduced under the modified boundary conditions, providing a strong basis for the selection of water-preserving coal mining methods and valuable experience for the mining of coal seams in areas with similar conditions.

During 2009/2010, study was carried out to assess agrochemicals use practice and its potential risk on honeybees and beekeeping activities in Seka Chekorsa district of Jimma zone of Oromia. A total of 240 farmer respondents from two rural peasant associations were interviewed using pretested partially structured questionnaires. Focus group discussion was held in the peasant associations for data collection. About 83.3 % of the study participants used different types of agrochemicals (insecticides, herbicides and fungicides) at different levels.50.8%, 22.2%, 13.3%, 7.9%, 3.8% and 2.1% of the respondents did use agrochemicals for fungal, insect, weed, quality product, others and other diseases in decreasing order of importance respectively. Majority of Farmers in the study area have practiced spray form of agrochemicals application as compared to other forms. Even though , there was variability, farmers apply agrochemicals mainly at flowering stage of nearly all cultivated crops. Most of the farmers apply agrochemicals during winter season following irrigation farming in the study area. The respondent farmers confirmed that agrochemicals had affected beekeeping activities in several ways. From the respondents view and field observation in the present study, it is evident to report that agrochemical are recklessly used and do have high risk to beekeeping activities and honeybees population in the study area. Therefore, all stake takers should cooperate to mitigate agrochemicals use practice impact on honeybee population in the ecosystem. Frequent training has to be provided for both beekeepers and crop growers on the sustainable use of agrochemicals and approaches that will lessen potential harm that might be posed to honeybees due to misuse of agrochemicals. Further study is needed to examine actual impact of agrochemicals on beekeeping and honeybees using a rigorous research approach under laboratory and field conditions.

Pesticides are widely used compounds against pest in agriculture. Although chemical pesticides had made a great contribution to the fight against pests and diseases, nowadays, their indiscriminate use are posing serious ecological consequences. The present review highlights the side effect, accelerating factors, and management strategies of pesticide use on environmental constituents. Pesticides cause serious hazards to agricultural environment and human health as a lot of them and their derivatives remain in the environmental system for a considerable period. Most of them have adverse effects on soil and soil microbes, beneficial organisms and species diversity, fresh water community, water quality and air ecosystem, human health, and sustainable pest management. Moreover, pesticides cause imbalance of biodiversity which directly affects agricultural productivity and/or crop yield. On the other hand, increasing world population, repeated use of persistent and non-biodegradable pesticides, and lack of judicious pesticide usage, weak linkage among stock holders and weak pesticide governance are among factors which contribute in acceleration of ecological impact of pesticides. Hence, proper utilization or effective management of pesticides is compulsory to protect our environment and eventually health hazards associated with it. Adoption of alternative pest control options like integrated pest management, appropriate agronomic practices, resistant/tolerant varieties, bio-control, natural substances, and safe application of minimal toxic synthetic pesticides as a last resort are key measures to mitigate the risk. Likewise, there is a need for more awareness rising among farmers, distributors, industry, policymakers, and other stakeholders in the judicious and discriminate use of pesticides which is critical to reducing the side effects on humans and the environment. Furthermore, activities that increase environmental awareness and safety of pesticides should be initiated by the agrochemical firms and governments.

The study of the relationship between humans and nature in the past is Environmental history. Environmental history was well-known as a new discipline in the 1977 at the American society. Its study in Africa lies in its emphasis on colonial capitalism and imperialism as environmental contexts and processes. The study in Africa was the results of colonialism because of the environmental degradation and prolonged to multi-faced environmental problem. Study in Ethiopia was ignored due to the emphasis of studies for political centers and political elites. Likewise other part of Ethiopia, the environmental history in Ayu Guagusa District was not well studied. Ayu Guagusa woreda was positioned in the Awi Administrative Zone, Northwest Ethiopia. The district populated by ethnically diverse. The diverse peoples produced the maize, pepper corn, wheat, téff, Dagussa, barely and bean through practice of traditional agricultural system. Following land reform since 1975, the government formed Peasant association in the study area. Then, the villagazition, resettlement and other programs were also introduced by the socialist government to instruct the ideology into the rural peasant. The programs negatively resulted soil degradation in the district. This land degradation rehabilitated by measures such as reforestation, afforestation, gave awareness for the local peoples, terracing, crop rotation, animal manure and counter plough in the district.

This short note is of interest for depleted uranium cleaning and supraconductivity studies. It presents ways to cleanse depleted uranium efficiently.

Human lung cancer is the most prevalent cancer worldwide that consisting of two main subtypes: the non-small cell lung cancer (NSCLC) and the small cell lung cancer (SCLC). NSCLC comprises over 80% of lung cancer and the treatment of NSCLC is mostly guided by tumor stage, although distinctive molecular characteristics between two major subtypes of NSCLC, i.e., lung adenocarcinoma (LUAD) and squamous cell lung carcinoma (LUSC), have been increasingly identified. In this study, we integrated the gene expression data and methylation data to investigate the genetic differences between LUAD and LUSC. We further applied the Boruta package to select key features from LUAD and LUSC tumor samples to build predictive models of tumor stage. We finally obtained 6 key gene expression features and 4 key methylation features that can be reliably used in prediction of LUAD and LUSC stage.

Inadequacy of rock mechanics chamber test devices and test systems that cannot accurately simulate gradient static stresses on specimens, this paper presented an innovative testing technique, which relates to the stress wave propagation of rock subjected gradient static stress. The method involves modification of a split Hopkinson pressure bar, such that the test specimen is subjected to gradient static stress and axial impact loading. The device has the features of simple loading and multiple static stress gradients, which verifies the feasibility of stress wave propagation test of red sandstone specimens under linear gradient static stress and conducts stress wave propagation test of red sandstone specimens under linear gradient static stress. Tests on red sandstone specimens with different static stress gradients show that the stress wave propagation of the specimens under gradient static stress is different with their corresponding homogeneous static stress state. The attenuation coefficients of stress waves are different under different conditions, and loading gradient static stress can accelerate the attenuation process. The results of this study will be useful for the analysis of stress wave propagation in deep engineering blasting and the stability analysis of adjacent structures.

The study investigated the challenges facing teachers’ implementing continuous assessment in the Tililli general and preparatory school with the emphasis on how these challenges influence effective teaching and learning and how a teacher deals with these challenges on a day to- day basis. For this study, a qualitative research method was selected. This method seeks to understand the diversified underlying challenges, understanding and experiences of the teacher in this study. In order to achieve this method, data collection instruments such as the questionnaire would be used to obtain reliable data, a pilot test and follow-up interviews were utilized. All teachers age, gender, name of subject and grade who teaches, teaching experience, professional qualification or whether they were permanent or temporary, local or foreign was included that participated in filled questionnaire and interview. All teachers recommended that the education should support teachers in implementing the continuous assessment by motivating them. The department should outsource trainers to train teachers.