The 2008 Wenchuan earthquake in Sichuan of China was the result of quake-triggering along an active several hundred-kilometer-long fault. The subsequent landslides and debris flow geohazards are dominating factors in ...The 2008 Wenchuan earthquake in Sichuan of China was the result of quake-triggering along an active several hundred-kilometer-long fault. The subsequent landslides and debris flow geohazards are dominating factors in planning post-disaster recovery and rebuilding. This paper presents recommendations for coping with large-scale geohazards and disasters. It is essential to establish a national emergency management system for huge scale catastrophe and earthquake precursor identification. Town construction must be kept away from active faults, especially to improve town safety in areas with high risk of seismic and geological hazards, and it is important to improve geohazard investigation and remediation for mountain areas that have become loosened by earthquake activity. Geological factors must be better understood to reduce direct and secondary risks and effects of earthquakes. Site selections for public relocation require clear and informed analysis of geological and social risk reduction, so that relocation, infrastructure reconstruction, and commemorative relic-sites can be protected.展开更多
Mountainous areas have been long recognized as particularly important for the planet and sustainable mountain development is a global priority. In order to improve the socioeconomic development perspectives of mountai...Mountainous areas have been long recognized as particularly important for the planet and sustainable mountain development is a global priority. In order to improve the socioeconomic development perspectives of mountain societies, efficient and well-targeted energy strategies should be formed. An important step towards this direction is adequate understanding of local conditions and specific features that affect energy sector. This procedure allows the inclusion of "locality" in energy planning and so, decentralized energy production is facilitated. The present study attempts to determine the particular energy identity of mountainous areas. Greece, which is the second most mountainous country in the EU, has been selected as a case study. Essential features of the mountainous space have been selected, namely altitude, inclination, remoteness, lack of productive activities, old buildings/vernacular architecture, in order to explore their interrelation with the energy sector. Based on literature review and research findings the interaction between mountainous character and energy is outlined. Therefore, a framework of the characteristics of mountain energy identity is composed, which can provide support to the formation of specialized energy policy for mountainous areas. Some of the main findings of the present study include the significantly increased energy loads of mountainous areas, the abundance of renewable energy potential in high – altitude areas, the vulnerability of mountain societies to energy poverty and the difficulties in sitting energy projects in the restricted usable space of mountains. Since the literature regarding mountains and energy is rather poor the present paper aspires to be a step towards highlighting the importance of energy issues for mountain areas and societies. By determining the features of mountain energy identity energy planning in high – altitude areas and so, helping make energy planning more effective, such research works can be parts of sustainable development strategies for mountainous areas.展开更多
Empirical research was done interviewing face to face a sample of 2,447, 10-12 grade students in Culiacan, Sinaloa, Mexico, from the main public university high school in town. Education is seen as a tool to develop b...Empirical research was done interviewing face to face a sample of 2,447, 10-12 grade students in Culiacan, Sinaloa, Mexico, from the main public university high school in town. Education is seen as a tool to develop better citizens first, and better workers later. The objective of this research was to detect different perceptions related to values and education. Using a 13 items questionnaire, we measured: Students' perceptions about him/herself as part of their education role, responsibility that students show toward activities m school, perceptions about education as a tool to grow in the social ladder and as a way of social recognition, social perception about effort as an important value to self-improve and get social recognition, and to finish, perceptions about their teacher's performance.展开更多
In this work a study of feasibility is illustrated to design and build a mobile robot for inspection and analysis of historical sites of architectonic interest. This novel application for robotic systems can be consid...In this work a study of feasibility is illustrated to design and build a mobile robot for inspection and analysis of historical sites of architectonic interest. This novel application for robotic systems can be considered of great interest because nowadays the need of more and more accurate and efficient survey activity requires enhancement and even development of procedures with more reliable, innovative, and advanced characteristics. Within this expectation robots and robotic systems seem to be suitable solutions even with the purposes of: operating in environments that cannot be reached by human operators. The study of feasibility concerns with the analysis and simulation of a robotic system that can be used for operating in historical sites. Basic features of such mobile robots, either legged or wheeled, are well known, but specific requirements should be considered for the proposed applications in archaeological/architectural sites, which can be considered as a novelty in the field of Robotics. Basic features of the proposed robotic system can be summarized as follows: the robot should be able to move inside the archaeological and/or architectural sites by carrying surveying devices and by avoiding damage of the surface and other parts of the site.展开更多
Based on data from an across-fault survey along the Sichuan-Yunnan rhombic block boundaries, the recent deformation characteristics on each fault have been analyzed. It was found that the rate of crustal deformation i...Based on data from an across-fault survey along the Sichuan-Yunnan rhombic block boundaries, the recent deformation characteristics on each fault have been analyzed. It was found that the rate of crustal deformation is slowing down along the northern segment and increasing along the southern segment. Each fault has different features of deformation. The horizontal deformation is mainly characterized by left-lateral strike-slip. The rate of vertical deformation is less than that of the horizontal deformation. The faults have the feature of upper wall uplifting alternated with descending. The anomaly changes of crustal deformation at some sites are closely related to the seismicities near the sites.展开更多
This paper deals with a new integrated method of reconstruction and forecasting of climatic changes in future. The method is based on proxy data pollen-spore analysis method, 14C analysis method, nowadays meteorologic...This paper deals with a new integrated method of reconstruction and forecasting of climatic changes in future. The method is based on proxy data pollen-spore analysis method, 14C analysis method, nowadays meteorological data, and data about of solar activity expressed in numbers of W (Wolf). Here we present the results of investigation of sediments of the 2nd Fomich River terrace, Taymyr Peninsula, Russia. The formation of the peat bog started 10500 ± 140 years BP and continued during the entire Holocene. The pollen analysis of the sediment samples of the 2nd Fomich River terrace and the analysis of surface samples from a larch forest, typical of this region, reveals two phytochrones: both climatically preconditioned--tundra phytochrone (I1-4) and forest phytochrone (Ⅱ1-4). The techniques of reconstruction and forecasting of basic elements of climate are presented and discussed in details.展开更多
The number of people playing Massive Multiplayer Online Games (MMOGs) is growing steadily, yet there are limited studies on the social impact that this online activity has. This research, using both quantitative and...The number of people playing Massive Multiplayer Online Games (MMOGs) is growing steadily, yet there are limited studies on the social impact that this online activity has. This research, using both quantitative and qualitative data, focused on whether users of the most popular MMOG, World of Warcraft (WOW), exhibited behaviors of social capital in their online gaming activity and whether there was any correlation to offiine social capital. The findings indicated that cooperation provided the best indicator to make a correlation about a gamer's offiine social capital behaviors. One conclusion, stemming from this is that, in virtual worlds, the added social capital can lead to cronyism and help those in power maintain the status quo.展开更多
Based on remote sensing data, field investigation and trench measurement along the piedmont fault (Wujumengkou Dongfengcun) of Mt. Serteng, the vertical displacement rate has been found to be 0 88~1 83mm/a since the ...Based on remote sensing data, field investigation and trench measurement along the piedmont fault (Wujumengkou Dongfengcun) of Mt. Serteng, the vertical displacement rate has been found to be 0 88~1 83mm/a since the late period of late Pleistocene and 0 89mm/a since the middle period of Holocene. Using the progressive constraining method,five paleoearthquake events have been distinguished from two large trenches since Holocene. They occurred 9000±1300a B.P., 6500±500a B.P., 5770a B.P., 4200±300a B.P. and 3250±250a B.P., respectively. From the late period of late Pleistocene to the beginning of Holocene, some paleoearthquake events may have been missed due to a variety of reasons. All of the paleoearthquake events displayed clustering characteristics to a certain extent. The first cluster was occurred around 8900a B.P., the second cluster occurred between 5700~6500a B.P. and the last cluster was occurred in 3250~4200 a B.P. The interval between the first cluster and the second cluster was about 2400a while that between the second cluster and the third cluster was only 1570a. No earthquake events have cut the ground surface along this active fault segment since 3250a B.P. The lapse time is more than the recurrence interval between two paleoearthquake clusters. Therefore, there is a potential risk for a recurring earthquake along this active fault segment.展开更多
Seismicity in northern Arizona is concentrated in a northwest-southeast trending belt that stretches from the Utah border south to the edge of the Colorado Plateau. Located within this NASB (Northern Arizona Seismic ...Seismicity in northern Arizona is concentrated in a northwest-southeast trending belt that stretches from the Utah border south to the edge of the Colorado Plateau. Located within this NASB (Northern Arizona Seismic Belt) is the San Francisco volcanic field, classified by the United States Geological Survey as potentially active. The last volcanic event in the field was located at Sunset Crater and occurred less than 1,000 years ago. Eruption intervals in the volcanic field are of the same order of length of time. Seismic monitoring of the volcanic field area has improved greatly since 1985 with the establishment of new network seismic stations. This has allowed for a lowered threshold of detection of seismic events and improved location capabilities. As an example of the result of this improved ability to locate smaller tremors, two swarms have been identified in the field, the 2009 Halloween swarm near Sunset Crater volcano and the 2011 swarm near Flagstaff, the largest urban community in northern Arizona.展开更多
fMRI (Functional Magnetic Resonance Imaging) is a relatively new technique that uses MRI (Magnetic Resonance Imaging) to measure the hemodynamic response (change in blood flow) related to neural activity in the ...fMRI (Functional Magnetic Resonance Imaging) is a relatively new technique that uses MRI (Magnetic Resonance Imaging) to measure the hemodynamic response (change in blood flow) related to neural activity in the brain. This paper aims to explore and identify the obstacles facing the implementation and applications of IMRI in radiology departments within Jeddah city by analyzing related data received by direct questionnaires and interviews with all the people working in MRI units in Jeddah city and finds that the major obstacle is lacking of awareness of fMRI among medical professionals and their training.展开更多
In this paper,based on the collected data and earthquake field investigation,characteristics of the MS4.1 Hujiaping earthquake of November 22,2008 at Guizhou town in Zigui county,Hubei Province and the geological and ...In this paper,based on the collected data and earthquake field investigation,characteristics of the MS4.1 Hujiaping earthquake of November 22,2008 at Guizhou town in Zigui county,Hubei Province and the geological and hydrogeological conditions and seismicity background of the area are analyzed,and the earthquake disaster is presented. Some scientific issues relating to earthquake precursors and the cause of the earthquake is discussed. The authors consider that the earthquake is a tectonic type reservoir-induced earthquake,occurring along the Xiannvshan fault under the joint action of reservoir water loading and water infiltration,and that there were certain suspected anomalies appearing in the gravity field before the earthquake. The cause of the earthquake may also be related to the effect of the Wenchuan earthquake on the local stress field.展开更多
The evaluation model which is dominated by formative evaluation can help the teacher diagnose the teaching activity in the process of students learning and timely find the problems, which can timely correct and contro...The evaluation model which is dominated by formative evaluation can help the teacher diagnose the teaching activity in the process of students learning and timely find the problems, which can timely correct and control the teaching and learning strategies. The questionnaire survey, oral English test, experimental research design and practice prove that establishing a dynamically professional oral English formative evaluation based on student behavior not only has good backwash effect, ensure the enthusiasm and interest of students learning oral English, but also can enhance the autonomic learning awareness and ability of students and improve the cooperative learning and communicative ability of students, which greatly improve the learning effect of students.展开更多
Social media are popular among youth for sharing information. This study tries to explore the popularity of the social media sites, the level of use of the social media sites, the types of information-sharing activiti...Social media are popular among youth for sharing information. This study tries to explore the popularity of the social media sites, the level of use of the social media sites, the types of information-sharing activities involved on the social media sites, to compare youth of various background in relation to information-sharing activities, and to analyze the relationship between the level of social media use and the information-sharing activities among youth. This study employs a quantitative research design, using survey method with questionnaire as the research instrument used for data collection. In this study, youth aged between 17-40 years old nationwide were surveyed. The study was developed based on the user and gratification theory (Blumler & Katz, 1974). Findings showed that youth always (five to seven days per week) use social media to share information including personal information. Results also showed that youth used the social media more for sharing negatively-oriented information compared to the positively-oriented information. Although there were more items on the positively-oriented information-sharing activities but more youth spent their time on the negatively-oriented information-sharing activities. The results are supported by a strong relationship between frequency of use and the negatively-oriented information-sharing activities.展开更多
To determine the climate changes that are due to natural variability and those due to human activities is quite challenging,just like delineating the impacts.Moreover,it is equally difficult to ascertain the adaptive ...To determine the climate changes that are due to natural variability and those due to human activities is quite challenging,just like delineating the impacts.Moreover,it is equally difficult to ascertain the adaptive strategies for coping with the climate changes and in particular for developing countries like Kenya.While climate change is a global phenomenon,the impacts are more or less specific to local areas such as observed in Kenyan case.Therefore climate change impacts adaptation strategies are appropriately applicable to a given local perspective.The study investigated the main indicators of climate change and effective adaptive strategies that can be employed in Kenya.Based on online questionnaire survey,the study established unpredictable rainfall patterns as the major indicator of climate change in the country,while water harvesting and change of cropping methods are the best adaptive strategies.展开更多
Begomoviruses are important crop viral disease agents, and they are transmitted by whiteflies of the Bemisia tabaci complex.Although the transmission of begomoviruses by whiteflies has been studied for many years, the...Begomoviruses are important crop viral disease agents, and they are transmitted by whiteflies of the Bemisia tabaci complex.Although the transmission of begomoviruses by whiteflies has been studied for many years, the mechanisms governing differential transmission of begomoviruses by different species of the Bemisia tabaci complex remain largely unknown. Here we firstly compared the transmission efficiency of tobacco curly shoot virus(TbCSV) by four species of the B. tabaci complex and found that Asia II 1 transmitted this virus with the highest efficiency, whereas MEAM1 transmitted it with the lowest. Next, by performing quantitative analysis of virus and immune-fluorescence detection, we found that the efficiency of TbCSV to cross the midgut wall was higher in Asia II 1 than in MEAM1. Finally, we set the quantities of virions in the haemolymph to the same level in Asia II 1 and MEAM1 via injection and then compared their capacity in TbCSV transmission, and found that the difference in TbCSV transmission between them became smaller. Taken together, our findings suggest that the efficiency of a begomovirus to cross the midgut wall of a whitefly to reach the vector's haemolymph plays a significant role in determining transmission of the virus.展开更多
The polymer N2200, with its π-conjugated backbone composed of alternating naphthalene diimide(NDI) and bithiophene(DT)units, has been widely used as an acceptor for all-polymer solar cells(all-PSCs) owing to its high...The polymer N2200, with its π-conjugated backbone composed of alternating naphthalene diimide(NDI) and bithiophene(DT)units, has been widely used as an acceptor for all-polymer solar cells(all-PSCs) owing to its high electron mobility and suitable ionization potential and electron affinity. Here, we developed two naphthalene diimide derivatives by modifying the molecular geometry of N2200 through the incorporation of a truxene unit as the core and NDI-DTas the branches. These starburst polymers exhibited absorption spectra and molecular orbital energy levels that were comparable to N2200. These copolymers were paired with the wide-bandgap polymer donor PTz BI-O to fabricate all-polymer solar cells(all-PSCs), which displayed impressive power conversion efficiencies up to 8.00%. The improved photovoltaic performances of all-PSCs based on these newly developed starburst acceptors can be ascribed to the combination of increased charge carrier mobilities, reduced bimolecular recombination, and formation of more favorable film morphology. These findings demonstrate that the construction of starburst polymer acceptors is a feasible strategy for the fabrication of high-performance all-PSCs.展开更多
The CCD photometric observation of comet 103P/Hartley 2 with broadband optical filters was carried out at Xuyi Station of Purple Mountain Observatory, Chinese Academy of Sciences by use of Near Earth Object Telescope ...The CCD photometric observation of comet 103P/Hartley 2 with broadband optical filters was carried out at Xuyi Station of Purple Mountain Observatory, Chinese Academy of Sciences by use of Near Earth Object Telescope (NEOT). We monitored the comet from September 30 to November 4, 2010 and investigated the variation of activities. The Afp parameter derived from our r broadband data varies from 46.0 to 126.0 cm and increases with time. The dust production rate in terms of Afp was measured and a tentative calculation of the dust (or gas) loss-rate of nucleus was executed under the assumption that the nucleus of comet 103P/l-lartley 2 is spherical. The r-band image and the surface brightness profile taken on September 30, 2010 was measured and the gradient of surface brightness profile of 103P/Hartley 2 showed m 〈 -1.5,展开更多
基金supported by the National Basic Research Program of the Ministry of Science and Technology of the People’s Republic of China (973 Project, Grant No. 2008CB425801)
文摘The 2008 Wenchuan earthquake in Sichuan of China was the result of quake-triggering along an active several hundred-kilometer-long fault. The subsequent landslides and debris flow geohazards are dominating factors in planning post-disaster recovery and rebuilding. This paper presents recommendations for coping with large-scale geohazards and disasters. It is essential to establish a national emergency management system for huge scale catastrophe and earthquake precursor identification. Town construction must be kept away from active faults, especially to improve town safety in areas with high risk of seismic and geological hazards, and it is important to improve geohazard investigation and remediation for mountain areas that have become loosened by earthquake activity. Geological factors must be better understood to reduce direct and secondary risks and effects of earthquakes. Site selections for public relocation require clear and informed analysis of geological and social risk reduction, so that relocation, infrastructure reconstruction, and commemorative relic-sites can be protected.
文摘Mountainous areas have been long recognized as particularly important for the planet and sustainable mountain development is a global priority. In order to improve the socioeconomic development perspectives of mountain societies, efficient and well-targeted energy strategies should be formed. An important step towards this direction is adequate understanding of local conditions and specific features that affect energy sector. This procedure allows the inclusion of "locality" in energy planning and so, decentralized energy production is facilitated. The present study attempts to determine the particular energy identity of mountainous areas. Greece, which is the second most mountainous country in the EU, has been selected as a case study. Essential features of the mountainous space have been selected, namely altitude, inclination, remoteness, lack of productive activities, old buildings/vernacular architecture, in order to explore their interrelation with the energy sector. Based on literature review and research findings the interaction between mountainous character and energy is outlined. Therefore, a framework of the characteristics of mountain energy identity is composed, which can provide support to the formation of specialized energy policy for mountainous areas. Some of the main findings of the present study include the significantly increased energy loads of mountainous areas, the abundance of renewable energy potential in high – altitude areas, the vulnerability of mountain societies to energy poverty and the difficulties in sitting energy projects in the restricted usable space of mountains. Since the literature regarding mountains and energy is rather poor the present paper aspires to be a step towards highlighting the importance of energy issues for mountain areas and societies. By determining the features of mountain energy identity energy planning in high – altitude areas and so, helping make energy planning more effective, such research works can be parts of sustainable development strategies for mountainous areas.
文摘Empirical research was done interviewing face to face a sample of 2,447, 10-12 grade students in Culiacan, Sinaloa, Mexico, from the main public university high school in town. Education is seen as a tool to develop better citizens first, and better workers later. The objective of this research was to detect different perceptions related to values and education. Using a 13 items questionnaire, we measured: Students' perceptions about him/herself as part of their education role, responsibility that students show toward activities m school, perceptions about education as a tool to grow in the social ladder and as a way of social recognition, social perception about effort as an important value to self-improve and get social recognition, and to finish, perceptions about their teacher's performance.
文摘In this work a study of feasibility is illustrated to design and build a mobile robot for inspection and analysis of historical sites of architectonic interest. This novel application for robotic systems can be considered of great interest because nowadays the need of more and more accurate and efficient survey activity requires enhancement and even development of procedures with more reliable, innovative, and advanced characteristics. Within this expectation robots and robotic systems seem to be suitable solutions even with the purposes of: operating in environments that cannot be reached by human operators. The study of feasibility concerns with the analysis and simulation of a robotic system that can be used for operating in historical sites. Basic features of such mobile robots, either legged or wheeled, are well known, but specific requirements should be considered for the proposed applications in archaeological/architectural sites, which can be considered as a novelty in the field of Robotics. Basic features of the proposed robotic system can be summarized as follows: the robot should be able to move inside the archaeological and/or architectural sites by carrying surveying devices and by avoiding damage of the surface and other parts of the site.
文摘Based on data from an across-fault survey along the Sichuan-Yunnan rhombic block boundaries, the recent deformation characteristics on each fault have been analyzed. It was found that the rate of crustal deformation is slowing down along the northern segment and increasing along the southern segment. Each fault has different features of deformation. The horizontal deformation is mainly characterized by left-lateral strike-slip. The rate of vertical deformation is less than that of the horizontal deformation. The faults have the feature of upper wall uplifting alternated with descending. The anomaly changes of crustal deformation at some sites are closely related to the seismicities near the sites.
文摘This paper deals with a new integrated method of reconstruction and forecasting of climatic changes in future. The method is based on proxy data pollen-spore analysis method, 14C analysis method, nowadays meteorological data, and data about of solar activity expressed in numbers of W (Wolf). Here we present the results of investigation of sediments of the 2nd Fomich River terrace, Taymyr Peninsula, Russia. The formation of the peat bog started 10500 ± 140 years BP and continued during the entire Holocene. The pollen analysis of the sediment samples of the 2nd Fomich River terrace and the analysis of surface samples from a larch forest, typical of this region, reveals two phytochrones: both climatically preconditioned--tundra phytochrone (I1-4) and forest phytochrone (Ⅱ1-4). The techniques of reconstruction and forecasting of basic elements of climate are presented and discussed in details.
文摘The number of people playing Massive Multiplayer Online Games (MMOGs) is growing steadily, yet there are limited studies on the social impact that this online activity has. This research, using both quantitative and qualitative data, focused on whether users of the most popular MMOG, World of Warcraft (WOW), exhibited behaviors of social capital in their online gaming activity and whether there was any correlation to offiine social capital. The findings indicated that cooperation provided the best indicator to make a correlation about a gamer's offiine social capital behaviors. One conclusion, stemming from this is that, in virtual worlds, the added social capital can lead to cronyism and help those in power maintain the status quo.
文摘Based on remote sensing data, field investigation and trench measurement along the piedmont fault (Wujumengkou Dongfengcun) of Mt. Serteng, the vertical displacement rate has been found to be 0 88~1 83mm/a since the late period of late Pleistocene and 0 89mm/a since the middle period of Holocene. Using the progressive constraining method,five paleoearthquake events have been distinguished from two large trenches since Holocene. They occurred 9000±1300a B.P., 6500±500a B.P., 5770a B.P., 4200±300a B.P. and 3250±250a B.P., respectively. From the late period of late Pleistocene to the beginning of Holocene, some paleoearthquake events may have been missed due to a variety of reasons. All of the paleoearthquake events displayed clustering characteristics to a certain extent. The first cluster was occurred around 8900a B.P., the second cluster occurred between 5700~6500a B.P. and the last cluster was occurred in 3250~4200 a B.P. The interval between the first cluster and the second cluster was about 2400a while that between the second cluster and the third cluster was only 1570a. No earthquake events have cut the ground surface along this active fault segment since 3250a B.P. The lapse time is more than the recurrence interval between two paleoearthquake clusters. Therefore, there is a potential risk for a recurring earthquake along this active fault segment.
文摘Seismicity in northern Arizona is concentrated in a northwest-southeast trending belt that stretches from the Utah border south to the edge of the Colorado Plateau. Located within this NASB (Northern Arizona Seismic Belt) is the San Francisco volcanic field, classified by the United States Geological Survey as potentially active. The last volcanic event in the field was located at Sunset Crater and occurred less than 1,000 years ago. Eruption intervals in the volcanic field are of the same order of length of time. Seismic monitoring of the volcanic field area has improved greatly since 1985 with the establishment of new network seismic stations. This has allowed for a lowered threshold of detection of seismic events and improved location capabilities. As an example of the result of this improved ability to locate smaller tremors, two swarms have been identified in the field, the 2009 Halloween swarm near Sunset Crater volcano and the 2011 swarm near Flagstaff, the largest urban community in northern Arizona.
文摘fMRI (Functional Magnetic Resonance Imaging) is a relatively new technique that uses MRI (Magnetic Resonance Imaging) to measure the hemodynamic response (change in blood flow) related to neural activity in the brain. This paper aims to explore and identify the obstacles facing the implementation and applications of IMRI in radiology departments within Jeddah city by analyzing related data received by direct questionnaires and interviews with all the people working in MRI units in Jeddah city and finds that the major obstacle is lacking of awareness of fMRI among medical professionals and their training.
文摘In this paper,based on the collected data and earthquake field investigation,characteristics of the MS4.1 Hujiaping earthquake of November 22,2008 at Guizhou town in Zigui county,Hubei Province and the geological and hydrogeological conditions and seismicity background of the area are analyzed,and the earthquake disaster is presented. Some scientific issues relating to earthquake precursors and the cause of the earthquake is discussed. The authors consider that the earthquake is a tectonic type reservoir-induced earthquake,occurring along the Xiannvshan fault under the joint action of reservoir water loading and water infiltration,and that there were certain suspected anomalies appearing in the gravity field before the earthquake. The cause of the earthquake may also be related to the effect of the Wenchuan earthquake on the local stress field.
文摘The evaluation model which is dominated by formative evaluation can help the teacher diagnose the teaching activity in the process of students learning and timely find the problems, which can timely correct and control the teaching and learning strategies. The questionnaire survey, oral English test, experimental research design and practice prove that establishing a dynamically professional oral English formative evaluation based on student behavior not only has good backwash effect, ensure the enthusiasm and interest of students learning oral English, but also can enhance the autonomic learning awareness and ability of students and improve the cooperative learning and communicative ability of students, which greatly improve the learning effect of students.
文摘Social media are popular among youth for sharing information. This study tries to explore the popularity of the social media sites, the level of use of the social media sites, the types of information-sharing activities involved on the social media sites, to compare youth of various background in relation to information-sharing activities, and to analyze the relationship between the level of social media use and the information-sharing activities among youth. This study employs a quantitative research design, using survey method with questionnaire as the research instrument used for data collection. In this study, youth aged between 17-40 years old nationwide were surveyed. The study was developed based on the user and gratification theory (Blumler & Katz, 1974). Findings showed that youth always (five to seven days per week) use social media to share information including personal information. Results also showed that youth used the social media more for sharing negatively-oriented information compared to the positively-oriented information. Although there were more items on the positively-oriented information-sharing activities but more youth spent their time on the negatively-oriented information-sharing activities. The results are supported by a strong relationship between frequency of use and the negatively-oriented information-sharing activities.
文摘To determine the climate changes that are due to natural variability and those due to human activities is quite challenging,just like delineating the impacts.Moreover,it is equally difficult to ascertain the adaptive strategies for coping with the climate changes and in particular for developing countries like Kenya.While climate change is a global phenomenon,the impacts are more or less specific to local areas such as observed in Kenyan case.Therefore climate change impacts adaptation strategies are appropriately applicable to a given local perspective.The study investigated the main indicators of climate change and effective adaptive strategies that can be employed in Kenya.Based on online questionnaire survey,the study established unpredictable rainfall patterns as the major indicator of climate change in the country,while water harvesting and change of cropping methods are the best adaptive strategies.
基金supported by the National Natural Science Foundation of China (31390421)
文摘Begomoviruses are important crop viral disease agents, and they are transmitted by whiteflies of the Bemisia tabaci complex.Although the transmission of begomoviruses by whiteflies has been studied for many years, the mechanisms governing differential transmission of begomoviruses by different species of the Bemisia tabaci complex remain largely unknown. Here we firstly compared the transmission efficiency of tobacco curly shoot virus(TbCSV) by four species of the B. tabaci complex and found that Asia II 1 transmitted this virus with the highest efficiency, whereas MEAM1 transmitted it with the lowest. Next, by performing quantitative analysis of virus and immune-fluorescence detection, we found that the efficiency of TbCSV to cross the midgut wall was higher in Asia II 1 than in MEAM1. Finally, we set the quantities of virions in the haemolymph to the same level in Asia II 1 and MEAM1 via injection and then compared their capacity in TbCSV transmission, and found that the difference in TbCSV transmission between them became smaller. Taken together, our findings suggest that the efficiency of a begomovirus to cross the midgut wall of a whitefly to reach the vector's haemolymph plays a significant role in determining transmission of the virus.
基金supported by the Ministry of Science and Technology of China(2014CB643501)the National Natural Science Foundation of China(51673069,91633301,21520102006,21761132001)+1 种基金Foundation of Guangzhou Science and Technology Project(201707020019,201607020010)the Pearl River S&T Nova Program of Guangzhou(201710010021)
文摘The polymer N2200, with its π-conjugated backbone composed of alternating naphthalene diimide(NDI) and bithiophene(DT)units, has been widely used as an acceptor for all-polymer solar cells(all-PSCs) owing to its high electron mobility and suitable ionization potential and electron affinity. Here, we developed two naphthalene diimide derivatives by modifying the molecular geometry of N2200 through the incorporation of a truxene unit as the core and NDI-DTas the branches. These starburst polymers exhibited absorption spectra and molecular orbital energy levels that were comparable to N2200. These copolymers were paired with the wide-bandgap polymer donor PTz BI-O to fabricate all-polymer solar cells(all-PSCs), which displayed impressive power conversion efficiencies up to 8.00%. The improved photovoltaic performances of all-PSCs based on these newly developed starburst acceptors can be ascribed to the combination of increased charge carrier mobilities, reduced bimolecular recombination, and formation of more favorable film morphology. These findings demonstrate that the construction of starburst polymer acceptors is a feasible strategy for the fabrication of high-performance all-PSCs.
基金support of the National Natural Science Foundation of China(Grant Nos. 11003048, 10933004 and 10803022)Minor Planet Foundation of Purple Mountain Observatory and the exchange program between Finnish Academy (FA) and NSFC
文摘The CCD photometric observation of comet 103P/Hartley 2 with broadband optical filters was carried out at Xuyi Station of Purple Mountain Observatory, Chinese Academy of Sciences by use of Near Earth Object Telescope (NEOT). We monitored the comet from September 30 to November 4, 2010 and investigated the variation of activities. The Afp parameter derived from our r broadband data varies from 46.0 to 126.0 cm and increases with time. The dust production rate in terms of Afp was measured and a tentative calculation of the dust (or gas) loss-rate of nucleus was executed under the assumption that the nucleus of comet 103P/l-lartley 2 is spherical. The r-band image and the surface brightness profile taken on September 30, 2010 was measured and the gradient of surface brightness profile of 103P/Hartley 2 showed m 〈 -1.5,