Two non-destructive analytical techniques (gamma spectrometer and X-ray diffractometer) were employed in the analysis of bauxite and rutile ore and their vicinity soil and control sourced within the Kanam and Wase min...Two non-destructive analytical techniques (gamma spectrometer and X-ray diffractometer) were employed in the analysis of bauxite and rutile ore and their vicinity soil and control sourced within the Kanam and Wase mineral exploration sites. The activity concentrations of natural radionuclides <sup>238</sup>U, <sup>232</sup>Th, and <sup>40</sup>K in the soil samples received from bauxite and rutile mineral mining vicinities revealed high concentrations of <sup>238</sup>U, <sup>232</sup>Th, and <sup>40</sup>K compared to the control soil samples sourced 500 m away from the mineral exploration vicinities. Radiological detriments RLI, AUI, Hin and Hex unveiled values exceeding the radiation standard concentration (>1) for soil. X-ray diffraction characterization of bauxite ore revealed the interlocking minerals of Bauxite (18)%, Albite (11)%, Garnet (15)%, Illite (6)% and Muscovite (43)% in various proportions obtained within the 2θ range (9.18 to 64.4) and a peak value (intensity, cps) of 3400. Pure bauxite percentage in the ore meets metallurgical grade (15 - 25)%. X-ray diffraction of rutile ore revealed the minerals of rutile (40)%, quartz (21.4)%, ilmenite (27)% and garnet (11.8)% found within the 2θ range (27.5 to 35.6) and a peak value intensity of 31.1 - 100.0 cps also meeting the metallurgical grade of 15% - 25%. The major environmental concern associated with the mineral-sands industry is the radiation hazards, pollution of ground-water sources from heavy metals, mineral transport with heavy equipment’s, dredging operations in fragile coastal area and clearing of vegetation.展开更多
During the years 2021 and 2022, the city of Maroua experienced repeated power blackouts. However, this locality has significant photovoltaic energy potential. Nevertheless, the evaluation of the electrical performance...During the years 2021 and 2022, the city of Maroua experienced repeated power blackouts. However, this locality has significant photovoltaic energy potential. Nevertheless, the evaluation of the electrical performance showed the dependence of the population on these fluctuations, which could be bypassed or suppressed. In most cases, the blackout occurs during high energy demand. In this paper, a method for evaluating electrical efficiency is proposed and its credibility has been demonstrated on the one hand, and on the other hand, a renewable energy production system is proposed. The Homer software has made possible the analysis of the proposed system and its impact on the environment has also been carried out. The techno-economic study of the system has proved that a solar photovoltaic farm associated with an energy storage system, with a capacity of 47 MW, can meet the energy demand of the town of Maroua. This alternative is profitable for this locality which lives in a precarious situation and a continuous need.展开更多
Anthropogenic, including mining activities leaves the environment contaminated with potentially toxic substances and remote hazards if not properly checked. The quest in this study is the levels of naturally occurring...Anthropogenic, including mining activities leaves the environment contaminated with potentially toxic substances and remote hazards if not properly checked. The quest in this study is the levels of naturally occurring radionuclides in Okobo coal, Nigeria and their possible distribution in coal mine vicinity soils, water and plants (cassava). Samples were characterized for levels of radionuclides and radiological detriments using high resolution gamma spectrometer, Gamma ray liquid scintillation and applicable radiological hazard indices. The range of mean activity concentrations (Bq·kg-1) for the environmental samples are as follows: 226Ra (8.39 ± 1.0 to 77.6 ± 4.0), 232Th (0.470 ± 0.4 and 77.8 ± 2), and 40K (29.1 ± 0.4 and 289 ± 6), with their respective mean values of 32.7 ± 2.1, 54.0 ± 1.5 and 158.8 ± 3.1 (Bq·kg-1). Radiological detriments including radium equivalent activity (Raeq), external hazard index (Hex), internal hazard index (Hin), radioactivity level index or gamma index (Iγ) and the ELCR for coal sample is 96.94 Bq·kg-1, 0.26, 0.30, 0.69, and 1.56 respectively. Reported values were below the safety limits stipulated by UNSCEAR and implied that the environment is relatively safe with low levels of natural radioactivity. Overall, this background study has demonstrated that Okobo coal mine is a less radio-hazard contributor to environmental samples. Exceptions to this generalization are representative gamma index (Iγr) and annual effective dose equivalent values for some cassava and soil samples, which may call for future impact monitoring.展开更多
Spermatozoa are constantly exposed to the interphase between oxidation through high amounts of reactive oxygen species (ROS) and leukocytes, and reduction by means of scavengers and antioxidants. Considering the ver...Spermatozoa are constantly exposed to the interphase between oxidation through high amounts of reactive oxygen species (ROS) and leukocytes, and reduction by means of scavengers and antioxidants. Considering the very special functions as being the only cells with such high polarization and exerting their functions outside the body, even in a different individual, the female genital tract, the membranes of these cells are chemically composed of an extraordinary high amount of polyunsaturated fatty acids. This in turn, renders them very susceptible to oxidative stress, which is defined as an imbalance between oxidation and reduction towards the oxidative status. As a result, ROS deriving from both leukocytes and the male germ cells themselves cause a process called 'lipid peroxidation' and other damages to the sperm cell. On the other hand, a certain limited amount of ROS iS essential in order to trigger vital physiological reactions in cells, including capacitation or the acrosome reaction in sperm. The treatment of patients with antioxidants to compensate the oxidative status caused by oxidative stress is highly debated as uncontrolled antioxidative treatment might derail the system towards the reduced status, which is also unphysiological and can even induce cancer. This paradox is called the 'antioxidant paradox'. Therefore, a proper andrological diagnostic work-up, including the evaluation of ROS levels and the antioxidant capacity of the semen, has to he carried out beforehand, aimed at keeping the fine balance between oxidation and scavenging of vital amounts of ROS.展开更多
Identification of individuals at risk for developing Alzheimers disease (AD) is an important issue for its pretreatment. Perspective studies predicting the disease are based on the genetic approaches emerging from the...Identification of individuals at risk for developing Alzheimers disease (AD) is an important issue for its pretreatment. Perspective studies predicting the disease are based on the genetic approaches emerging from the nucleotide polymorphism analysis in different loci through the entire genome in AD patients. Considerable diversity of genes located in these regions raise the question of this diversity's peculiar role in the disease development. The mechanisms of AD have been shown to be associated with the gene variation, increased beta-amyloid production and concomitant epileptiform activity/epilepsy in particular (Palop and Mucke, 2009).展开更多
The COVID-19 pandemic has caused higher educational institutions around the world to close campus-based activities and move to online delivery.The aim of this paper is to present the case of Global College of Engineer...The COVID-19 pandemic has caused higher educational institutions around the world to close campus-based activities and move to online delivery.The aim of this paper is to present the case of Global College of Engineering and Technology(GCET)and how its practices including teaching,students/staff support,assessments,and exam policies were affected.The paper investigates the mediating role of no detriment policy impact on students’result along with the challenges faced by the higher educational institution,recommendations and suggestions.The investigation concludes that the strategies adopted for online delivery,student support,assessments and exam policies have helped students to effectively cope with the teaching and learning challenges posed by the COVID-19 pandemic without affecting their academic results.The study shows that 99%of students were able to maintain the same or better level of performance during the 1st COVID-19 semester.One percent of students had shown a slight decrease in their performance(about 1%–2%)with respect to their overall marks pre-COVID-19.The no detriment policy has succoured those 1%of the students to maintain their overall performance to what it used to be pre-COVID-19 pandemic.Finally,the paper provides the list of challenges and suggestions for smooth conduction of online education.展开更多
Over the past 15 years,social media has play an increasingly role in our life.And in the meantime more and more peo-ple like using all kinds of social platforms to put them in the public eye.Their posts of pictures or...Over the past 15 years,social media has play an increasingly role in our life.And in the meantime more and more peo-ple like using all kinds of social platforms to put them in the public eye.Their posts of pictures or status updates to WeChat,Sina or other social media platforms create and maintain their online presence.However,in my opinion,I think it's unsuitable to overuse elec-tronic equipments to maintain our online presence.Because updating our pictures to social platforms will bring potential dangers.展开更多
A greater number of primary school students are inventing stories and telling lies when they are supposed to be writing about personal experiences. The Chengdu Business Daily said,of
文摘Two non-destructive analytical techniques (gamma spectrometer and X-ray diffractometer) were employed in the analysis of bauxite and rutile ore and their vicinity soil and control sourced within the Kanam and Wase mineral exploration sites. The activity concentrations of natural radionuclides <sup>238</sup>U, <sup>232</sup>Th, and <sup>40</sup>K in the soil samples received from bauxite and rutile mineral mining vicinities revealed high concentrations of <sup>238</sup>U, <sup>232</sup>Th, and <sup>40</sup>K compared to the control soil samples sourced 500 m away from the mineral exploration vicinities. Radiological detriments RLI, AUI, Hin and Hex unveiled values exceeding the radiation standard concentration (>1) for soil. X-ray diffraction characterization of bauxite ore revealed the interlocking minerals of Bauxite (18)%, Albite (11)%, Garnet (15)%, Illite (6)% and Muscovite (43)% in various proportions obtained within the 2θ range (9.18 to 64.4) and a peak value (intensity, cps) of 3400. Pure bauxite percentage in the ore meets metallurgical grade (15 - 25)%. X-ray diffraction of rutile ore revealed the minerals of rutile (40)%, quartz (21.4)%, ilmenite (27)% and garnet (11.8)% found within the 2θ range (27.5 to 35.6) and a peak value intensity of 31.1 - 100.0 cps also meeting the metallurgical grade of 15% - 25%. The major environmental concern associated with the mineral-sands industry is the radiation hazards, pollution of ground-water sources from heavy metals, mineral transport with heavy equipment’s, dredging operations in fragile coastal area and clearing of vegetation.
文摘During the years 2021 and 2022, the city of Maroua experienced repeated power blackouts. However, this locality has significant photovoltaic energy potential. Nevertheless, the evaluation of the electrical performance showed the dependence of the population on these fluctuations, which could be bypassed or suppressed. In most cases, the blackout occurs during high energy demand. In this paper, a method for evaluating electrical efficiency is proposed and its credibility has been demonstrated on the one hand, and on the other hand, a renewable energy production system is proposed. The Homer software has made possible the analysis of the proposed system and its impact on the environment has also been carried out. The techno-economic study of the system has proved that a solar photovoltaic farm associated with an energy storage system, with a capacity of 47 MW, can meet the energy demand of the town of Maroua. This alternative is profitable for this locality which lives in a precarious situation and a continuous need.
文摘Anthropogenic, including mining activities leaves the environment contaminated with potentially toxic substances and remote hazards if not properly checked. The quest in this study is the levels of naturally occurring radionuclides in Okobo coal, Nigeria and their possible distribution in coal mine vicinity soils, water and plants (cassava). Samples were characterized for levels of radionuclides and radiological detriments using high resolution gamma spectrometer, Gamma ray liquid scintillation and applicable radiological hazard indices. The range of mean activity concentrations (Bq·kg-1) for the environmental samples are as follows: 226Ra (8.39 ± 1.0 to 77.6 ± 4.0), 232Th (0.470 ± 0.4 and 77.8 ± 2), and 40K (29.1 ± 0.4 and 289 ± 6), with their respective mean values of 32.7 ± 2.1, 54.0 ± 1.5 and 158.8 ± 3.1 (Bq·kg-1). Radiological detriments including radium equivalent activity (Raeq), external hazard index (Hex), internal hazard index (Hin), radioactivity level index or gamma index (Iγ) and the ELCR for coal sample is 96.94 Bq·kg-1, 0.26, 0.30, 0.69, and 1.56 respectively. Reported values were below the safety limits stipulated by UNSCEAR and implied that the environment is relatively safe with low levels of natural radioactivity. Overall, this background study has demonstrated that Okobo coal mine is a less radio-hazard contributor to environmental samples. Exceptions to this generalization are representative gamma index (Iγr) and annual effective dose equivalent values for some cassava and soil samples, which may call for future impact monitoring.
文摘Spermatozoa are constantly exposed to the interphase between oxidation through high amounts of reactive oxygen species (ROS) and leukocytes, and reduction by means of scavengers and antioxidants. Considering the very special functions as being the only cells with such high polarization and exerting their functions outside the body, even in a different individual, the female genital tract, the membranes of these cells are chemically composed of an extraordinary high amount of polyunsaturated fatty acids. This in turn, renders them very susceptible to oxidative stress, which is defined as an imbalance between oxidation and reduction towards the oxidative status. As a result, ROS deriving from both leukocytes and the male germ cells themselves cause a process called 'lipid peroxidation' and other damages to the sperm cell. On the other hand, a certain limited amount of ROS iS essential in order to trigger vital physiological reactions in cells, including capacitation or the acrosome reaction in sperm. The treatment of patients with antioxidants to compensate the oxidative status caused by oxidative stress is highly debated as uncontrolled antioxidative treatment might derail the system towards the reduced status, which is also unphysiological and can even induce cancer. This paradox is called the 'antioxidant paradox'. Therefore, a proper andrological diagnostic work-up, including the evaluation of ROS levels and the antioxidant capacity of the semen, has to he carried out beforehand, aimed at keeping the fine balance between oxidation and scavenging of vital amounts of ROS.
文摘Identification of individuals at risk for developing Alzheimers disease (AD) is an important issue for its pretreatment. Perspective studies predicting the disease are based on the genetic approaches emerging from the nucleotide polymorphism analysis in different loci through the entire genome in AD patients. Considerable diversity of genes located in these regions raise the question of this diversity's peculiar role in the disease development. The mechanisms of AD have been shown to be associated with the gene variation, increased beta-amyloid production and concomitant epileptiform activity/epilepsy in particular (Palop and Mucke, 2009).
基金supported by Global College of Engineering and Technology(GCET).
文摘The COVID-19 pandemic has caused higher educational institutions around the world to close campus-based activities and move to online delivery.The aim of this paper is to present the case of Global College of Engineering and Technology(GCET)and how its practices including teaching,students/staff support,assessments,and exam policies were affected.The paper investigates the mediating role of no detriment policy impact on students’result along with the challenges faced by the higher educational institution,recommendations and suggestions.The investigation concludes that the strategies adopted for online delivery,student support,assessments and exam policies have helped students to effectively cope with the teaching and learning challenges posed by the COVID-19 pandemic without affecting their academic results.The study shows that 99%of students were able to maintain the same or better level of performance during the 1st COVID-19 semester.One percent of students had shown a slight decrease in their performance(about 1%–2%)with respect to their overall marks pre-COVID-19.The no detriment policy has succoured those 1%of the students to maintain their overall performance to what it used to be pre-COVID-19 pandemic.Finally,the paper provides the list of challenges and suggestions for smooth conduction of online education.
文摘Over the past 15 years,social media has play an increasingly role in our life.And in the meantime more and more peo-ple like using all kinds of social platforms to put them in the public eye.Their posts of pictures or status updates to WeChat,Sina or other social media platforms create and maintain their online presence.However,in my opinion,I think it's unsuitable to overuse elec-tronic equipments to maintain our online presence.Because updating our pictures to social platforms will bring potential dangers.
文摘A greater number of primary school students are inventing stories and telling lies when they are supposed to be writing about personal experiences. The Chengdu Business Daily said,of