In order to study the temporal variations of correlations between two time series,a running correlation coefficient(RCC)could be used.An RCC is calculated for a given time window,and the window is then moved sequentia...In order to study the temporal variations of correlations between two time series,a running correlation coefficient(RCC)could be used.An RCC is calculated for a given time window,and the window is then moved sequentially through time.The current calculation method for RCCs is based on the general definition of the Pearson product-moment correlation coefficient,calculated with the data within the time window,which we call the local running correlation coefficient(LRCC).The LRCC is calculated via the two anomalies corresponding to the two local means,meanwhile,the local means also vary.It is cleared up that the LRCC reflects only the correlation between the two anomalies within the time window but fails to exhibit the contributions of the two varying means.To address this problem,two unchanged means obtained from all available data are adopted to calculate an RCC,which is called the synthetic running correlation coefficient(SRCC).When the anomaly variations are dominant,the two RCCs are similar.However,when the variations of the means are dominant,the difference between the two RCCs becomes obvious.The SRCC reflects the correlations of both the anomaly variations and the variations of the means.Therefore,the SRCCs from different time points are intercomparable.A criterion for the superiority of the RCC algorithm is that the average value of the RCC should be close to the global correlation coefficient calculated using all data.The SRCC always meets this criterion,while the LRCC sometimes fails.Therefore,the SRCC is better than the LRCC for running correlations.We suggest using the SRCC to calculate the RCCs.展开更多
Accurate detection and picking of the P-phase onset time in noisy microseismic data from underground mines remains a big challenge. Reliable P-phase onset time picking is necessary for accurate source location needed ...Accurate detection and picking of the P-phase onset time in noisy microseismic data from underground mines remains a big challenge. Reliable P-phase onset time picking is necessary for accurate source location needed for planning and rescue operations in the event of failures. In this paper, a new technique based on the discrete stationary wavelet transform (DSWT)and higher order statist!cs, is proposed for processing noisy data from underground mines. The objectives of this method are to (1) Improve manual detection and tPicking of P-phase onset; and (ii) provide an automatic means of detecting and picking P-phase onset me accurately. The DSWT is first used to filter the signal over several scales. The manual P-phase onset detection and picking are then obtained by computing the signal energy across selected scales with frequency bands that capture the signal of interest. The automatic P-phase onset, on the other hand, is achieved by using skewness- and kurtosis-based criterion applied to selected scales in a time-frequency domain. The method was tested using synthetic and field data from an underground limestone mine. Results were compared with results obtained by using the short-term to long-term average (STA/LTA) ratio and that by Reference Ge et al. (2009). The results show that the me!hod provides a more reliable estimate of the P-phase onset arrival than the STA]LTA method when the signal to noise ratio is very low. Also, the results obtained from the field data matched accurately with the results from Reference Ge et al. (2009).展开更多
The present paper reviews the UN important efforts to promote global sustainable development in the chronological order since UN Conference on Human Environment in 1972, and ana- lyzes the progress and gap. The result...The present paper reviews the UN important efforts to promote global sustainable development in the chronological order since UN Conference on Human Environment in 1972, and ana- lyzes the progress and gap. The results show that the UN system has made great efforts for global sustainable development since the UN Conference on Human Environment, especially since UN Conference on Environment and Development, promoted the for- mation of important consensus and multilateral internhtional con- ventions on many fields, boosted the development of partnership in the field of sustainable development, and accelerated actions for sustainable development of many countries and regions. However, at present, the progress made is still far below the level required, prominently reflected in the slow progress toward the millen-nium development goals, the difficulties in negotiations in the field of environment and development, insufficient fulfillment of international agreements and conventions, and undesirable effects of partnership in the field of sustainable development. Based on these, the paper puts forward four suggestions for UN Conference on Sustainable Development in 2012(Rio+20): (1) to revitalize the "spirit of Rio" and accelerate the implementation of existing politi- cal commitments; (2) to make new political commitments focusing on climate change and other major global challenges under the Rio principles; (3) to lay out a blueprint of green economy under the Rio principles; and (4) to promote South-South cooperation as the focus of international cooperation.展开更多
In contrast with the large number of theatrical performances and filmic versions for television, both British and American, based on the play The Importance of Being Earnest (1975) by Oscar Wilde, there have only be...In contrast with the large number of theatrical performances and filmic versions for television, both British and American, based on the play The Importance of Being Earnest (1975) by Oscar Wilde, there have only been, so far, three films made for the cinema. Although one of them was made in the United States by the American director Kurt Baker in 1992, this paper will address only the two English versions, chronologically separated by a 50-year time span. It will focus on the cinematic adaptations made by English directors Anthony Asquith and Oliver Parker, the former in 1952 and the latter in 2002. Based on the same play, this comparative approach may throw some light on the evolution of cinematographic conditions and techniques as well as relate them to the expectations of audiences in the mid 20th century and at the beginning of the 21st century.展开更多
The scope and aim of this work is to describe the two-body interaction mediated by a particle (either the scalar or the gauge boson) within the light-front formulation. To do this, first of all we point out the impo...The scope and aim of this work is to describe the two-body interaction mediated by a particle (either the scalar or the gauge boson) within the light-front formulation. To do this, first of all we point out the importance of propagators and Green functions in Quantum Mechanics. Then we project the covariant quantum propagator onto the light front time to get the propagator for scalar particles in these coordinates. This operator propagates the wave function from x+ = 0 to x+ 〉 0. It corresponds to the definition of the time ordering operation in the light front time x+. We calculate the light-front Green's function for 2 interacting bosons propagating forward in x+. We also show how to write down the light front Green's function from the Feynman propagator and finally make a generalization to N bosons.展开更多
Endocytosis is a process through which extracellular materials are transported into cell through membrane deformation. This process is not a simple step-by-step process in which a series of proteins function according...Endocytosis is a process through which extracellular materials are transported into cell through membrane deformation. This process is not a simple step-by-step process in which a series of proteins function according to the chronological order, but rather a complex process comprising many members which are regulated precisely. The role of endocytosis is broadly divided into two categories, phagocytosis and pinocytosis, the latter is divided into four species in accordance with the size of endocytosis substances: clathrin dependent endocytosis, the diameter of clathrin-coated vesicle is 100-150 nm; caveolin dependent endocytosis, the diameter of caveolin protein-coated vesicle is 50-100 nm; macropinocytosis, the diam- eter of macropinocytosis is generally 0.5-2 μm, sometimes up to 5 μm; clathrin and caveolin independent endocytosis. Many proteins including endophilin A1, A2, A3, and endocytotic proteins B, B1a, and Blb as well as dynamin, actin and Rab protein families are involved in endocytosis and play an important role in different stages. The abnormal endocytosis may be involved in the development of certain diseases.展开更多
Translation involves not only formal transformation of two languages concerned, but also conversion of thought patterns. The oriental thought pattern is considered "concrete", "man-centered", and "ordinal"; whil...Translation involves not only formal transformation of two languages concerned, but also conversion of thought patterns. The oriental thought pattern is considered "concrete", "man-centered", and "ordinal"; while the western one is believed to be "abstract", "object-centered", and "conversed". These are the decisive factors for the existence of the differences in language expressing. It is of great importance to study these differences and make some adjustments in terms of syntactic structure, semantic focus, and time order so as to achieve a natural rending.展开更多
In this paper,we establish an invariance principle for ρ^--mixing random sequences under some moment condition.The result improve and extend the relevant result of Wu(2003).
The land issue remains a colonial legacy which Africa must resolve to facilitate the region's Before colonialism land was considered by communities as economic rather than a socio-economic advancements political reso...The land issue remains a colonial legacy which Africa must resolve to facilitate the region's Before colonialism land was considered by communities as economic rather than a socio-economic advancements political resource. Agricultural communities vacated land no longer fertile or useful for pasture. Conflicts over parcels of land were therefore rare and if they did occur often resulted in migration. Scramble over parcels of land was thus for need. However, with European scramble and arbitrary partition of Africa in the nineteenth century, formal boundaries were established by colonialists between colonies, a policy later pursued by colonial administrators between communities within colonies. Colonial policies and decolonization process in some colonies complicated the land problem, resulting in the scramble over land for greed by the newly independent states and communities. Land scrambled for greed engendered generalized conflicts. This paper thus intends to argue that the scramble over land for greed made land more a factor of contention than peace in Africa. A chronological-illustrative method, with references from the different geographical divide in Africa was adopted to explore the changing land usage and faces of land conflicts in Africa with the finality that land question in the region is largely a colonial problem.展开更多
Fiumara d'arte is an open-air museum of sculpture and contemporary art. Among the art-works of Fiumara d'arte, the Pyramid is the last one in order of time. It is a monumental sculpture made of COR-TEN steel, by the...Fiumara d'arte is an open-air museum of sculpture and contemporary art. Among the art-works of Fiumara d'arte, the Pyramid is the last one in order of time. It is a monumental sculpture made of COR-TEN steel, by the artist Mauro Staccioli and it is located on one specific point of the 38th parallel of latitude, on a hill of the northern mountains of Sicily. In this study the architectural and engineering features of land art-works built in this particular plein-air park are examined and discussed. After a general description of Fiumara d'Arte and its significance in the territory, the case of the Pyramid on the 38th parallel is focalized and a discussion of its architectural, artistic and environmental values is reported. Moreover the structural implications in its design and construction are explained, while the worst effects of external actions are underlined by showing the results of the analysis performed on a finite element model of the whole structure.展开更多
We consider the spectrum handoff delay of a Secondary User(SU)in cognitive radio networks.We propose a spectrum handoff scheme based on Recommended Channel Sensing Sequence(RCSS),which aims to optimise the spectrum ha...We consider the spectrum handoff delay of a Secondary User(SU)in cognitive radio networks.We propose a spectrum handoff scheme based on Recommended Channel Sensing Sequence(RCSS),which aims to optimise the spectrum handoff delay subject to the sensing reliability and link maintenance constraints.There are two cases that should be considered:1)the SU performs spectrum handoff successfully during the current frame,and 2)the SU successfully performs the spectrum handoff using several frames.We develop a dynamic programming algorithm for RCSS to identify the optimal sensing sequence for the first case,and an updating algorithm for RCSS to improve the handoff performance for the second case.The numerical results confirm that the proposed RCSS handoff scheme can achieve better handoff delay performance than others when the received signal-to-noise ratios of the Pus' signals on different channels are non-identical.展开更多
The enumerating algorithm has been introduced into the fitting procedure of the ASR model. Based on the detailed study of 21 large earthquakes with M≥6. 8 in the Chinese Mainland,the statistical features of seismic s...The enumerating algorithm has been introduced into the fitting procedure of the ASR model. Based on the detailed study of 21 large earthquakes with M≥6. 8 in the Chinese Mainland,the statistical features of seismic strain release before large earthquakes have been summarized. In the mass,the strain release models can be divided into five types. The first is the DA model,in which the strain release accelerates in broader areas and decelerates in small areas around the epicenter. Approximately 38% of earthquake samples are of this type. The second is the AD model,in which the strain release decelerates in broader areas and accelerates in smaller areas around the epicenter with an occupying ratioof approximately 19%. The third is ASR,in which only accelerating strain release can be observed. Cases of this model amount to about 14%. The fourth is DSR,in which only decelerating strain release can be checked,amounting to about 24%. There is only one earthquake sample of the fifth type (LSR),which shows a linear strain release. There is a 3~6 years difference in the duration of pre-shock sequences between the accelerating and decelerating models. This means that seismic quiescence against a background of increased seismicity of small earthquakes before large earthquakes are a typical feature in general. For the DA model,the average size of critical regions for steady accelerating and decelerating strain release is about 260km to 400km and 100km to 200km,respectively,3 to 5 times and 1 to 2 times the rupture size of an earthquake of magnitude 7. 0. The AD model is the opposite of the DA model. The model parameter,m value,has good stability. The ratio of ASR is about the same for accelerating seismic strain release phenomena,no matter what the strain release models are,or how large the strain release quantity is. With regard to decelerating seismic strain release phenomena, the DA model has the most distinctive decelerating strain release characteristic and is the typical feature of seismic strain release,i. e. "decelerating in-accelerating out seismic strain model".展开更多
Reading comprehension plays a vital role in English teaching and learning. It's impossible to learn English without reading. So for many years, English teachers have been engaging themselves in the research of tea...Reading comprehension plays a vital role in English teaching and learning. It's impossible to learn English without reading. So for many years, English teachers have been engaging themselves in the research of teaching reading effectively and they have proposed useful ways of teaching reading, such as bottom-up and top-down. Recently, the research in native English readers has shown that teaching of the text structure can facilitate first language reading. Based on the research in native English reading, the author carries out the research where top-level structure is applied to 'New Horizon College English'. The basic approaches in this essay are 'cause—effect' 'problem—solution' and 'time sequence'. The practice has proved that the application of top-level structure can guide the readers to build up the awareness of text structure and it can help the students overcome language and cultural barriers.展开更多
The extreme modern elevation of the Tianshan Mountains reflects the Cenozoic deformation. Apatite Fission Track (AFI) chronometry is widely used to study the latest cooling stages caused by tectonic process or by ex...The extreme modern elevation of the Tianshan Mountains reflects the Cenozoic deformation. Apatite Fission Track (AFI) chronometry is widely used to study the latest cooling stages caused by tectonic process or by exhumation in the uppermost crust. However, uncertainties remain over timing constraints on thermal history of the Tianshan Mountains since the Cenozoic though a great mount of dating work had been done in this area. To address this issue, modern river sands from the drainage basin on the piedmont of the Tianshan Mountains were sampled to integrate regional information. Single grains were dated with the AFT method, and then different grain-age components were identified to provide thermochronological constraints of their sources. Combined with discussion of previous dataset, our results show the multi-staged rapid cooling cluster at 46-32, 25-24, 19-13, 8-6, and -3 Ma, respectively. We interpreted these cooling events as a result of interplays between the Cenozo- ic tectonic uplift of the mountains and regional climate change.展开更多
基金supported by the Key Program of the National Natural Science Foundation of China (No. 41330960)the Global Change Research Program of China (No. 2015CB953900)
文摘In order to study the temporal variations of correlations between two time series,a running correlation coefficient(RCC)could be used.An RCC is calculated for a given time window,and the window is then moved sequentially through time.The current calculation method for RCCs is based on the general definition of the Pearson product-moment correlation coefficient,calculated with the data within the time window,which we call the local running correlation coefficient(LRCC).The LRCC is calculated via the two anomalies corresponding to the two local means,meanwhile,the local means also vary.It is cleared up that the LRCC reflects only the correlation between the two anomalies within the time window but fails to exhibit the contributions of the two varying means.To address this problem,two unchanged means obtained from all available data are adopted to calculate an RCC,which is called the synthetic running correlation coefficient(SRCC).When the anomaly variations are dominant,the two RCCs are similar.However,when the variations of the means are dominant,the difference between the two RCCs becomes obvious.The SRCC reflects the correlations of both the anomaly variations and the variations of the means.Therefore,the SRCCs from different time points are intercomparable.A criterion for the superiority of the RCC algorithm is that the average value of the RCC should be close to the global correlation coefficient calculated using all data.The SRCC always meets this criterion,while the LRCC sometimes fails.Therefore,the SRCC is better than the LRCC for running correlations.We suggest using the SRCC to calculate the RCCs.
文摘Accurate detection and picking of the P-phase onset time in noisy microseismic data from underground mines remains a big challenge. Reliable P-phase onset time picking is necessary for accurate source location needed for planning and rescue operations in the event of failures. In this paper, a new technique based on the discrete stationary wavelet transform (DSWT)and higher order statist!cs, is proposed for processing noisy data from underground mines. The objectives of this method are to (1) Improve manual detection and tPicking of P-phase onset; and (ii) provide an automatic means of detecting and picking P-phase onset me accurately. The DSWT is first used to filter the signal over several scales. The manual P-phase onset detection and picking are then obtained by computing the signal energy across selected scales with frequency bands that capture the signal of interest. The automatic P-phase onset, on the other hand, is achieved by using skewness- and kurtosis-based criterion applied to selected scales in a time-frequency domain. The method was tested using synthetic and field data from an underground limestone mine. Results were compared with results obtained by using the short-term to long-term average (STA/LTA) ratio and that by Reference Ge et al. (2009). The results show that the me!hod provides a more reliable estimate of the P-phase onset arrival than the STA]LTA method when the signal to noise ratio is very low. Also, the results obtained from the field data matched accurately with the results from Reference Ge et al. (2009).
文摘The present paper reviews the UN important efforts to promote global sustainable development in the chronological order since UN Conference on Human Environment in 1972, and ana- lyzes the progress and gap. The results show that the UN system has made great efforts for global sustainable development since the UN Conference on Human Environment, especially since UN Conference on Environment and Development, promoted the for- mation of important consensus and multilateral internhtional con- ventions on many fields, boosted the development of partnership in the field of sustainable development, and accelerated actions for sustainable development of many countries and regions. However, at present, the progress made is still far below the level required, prominently reflected in the slow progress toward the millen-nium development goals, the difficulties in negotiations in the field of environment and development, insufficient fulfillment of international agreements and conventions, and undesirable effects of partnership in the field of sustainable development. Based on these, the paper puts forward four suggestions for UN Conference on Sustainable Development in 2012(Rio+20): (1) to revitalize the "spirit of Rio" and accelerate the implementation of existing politi- cal commitments; (2) to make new political commitments focusing on climate change and other major global challenges under the Rio principles; (3) to lay out a blueprint of green economy under the Rio principles; and (4) to promote South-South cooperation as the focus of international cooperation.
文摘In contrast with the large number of theatrical performances and filmic versions for television, both British and American, based on the play The Importance of Being Earnest (1975) by Oscar Wilde, there have only been, so far, three films made for the cinema. Although one of them was made in the United States by the American director Kurt Baker in 1992, this paper will address only the two English versions, chronologically separated by a 50-year time span. It will focus on the cinematic adaptations made by English directors Anthony Asquith and Oliver Parker, the former in 1952 and the latter in 2002. Based on the same play, this comparative approach may throw some light on the evolution of cinematographic conditions and techniques as well as relate them to the expectations of audiences in the mid 20th century and at the beginning of the 21st century.
文摘The scope and aim of this work is to describe the two-body interaction mediated by a particle (either the scalar or the gauge boson) within the light-front formulation. To do this, first of all we point out the importance of propagators and Green functions in Quantum Mechanics. Then we project the covariant quantum propagator onto the light front time to get the propagator for scalar particles in these coordinates. This operator propagates the wave function from x+ = 0 to x+ 〉 0. It corresponds to the definition of the time ordering operation in the light front time x+. We calculate the light-front Green's function for 2 interacting bosons propagating forward in x+. We also show how to write down the light front Green's function from the Feynman propagator and finally make a generalization to N bosons.
基金Supported by grants from the National Natural Sciences Foundation of China (No. 30771126 and 30772106)
文摘Endocytosis is a process through which extracellular materials are transported into cell through membrane deformation. This process is not a simple step-by-step process in which a series of proteins function according to the chronological order, but rather a complex process comprising many members which are regulated precisely. The role of endocytosis is broadly divided into two categories, phagocytosis and pinocytosis, the latter is divided into four species in accordance with the size of endocytosis substances: clathrin dependent endocytosis, the diameter of clathrin-coated vesicle is 100-150 nm; caveolin dependent endocytosis, the diameter of caveolin protein-coated vesicle is 50-100 nm; macropinocytosis, the diam- eter of macropinocytosis is generally 0.5-2 μm, sometimes up to 5 μm; clathrin and caveolin independent endocytosis. Many proteins including endophilin A1, A2, A3, and endocytotic proteins B, B1a, and Blb as well as dynamin, actin and Rab protein families are involved in endocytosis and play an important role in different stages. The abnormal endocytosis may be involved in the development of certain diseases.
文摘Translation involves not only formal transformation of two languages concerned, but also conversion of thought patterns. The oriental thought pattern is considered "concrete", "man-centered", and "ordinal"; while the western one is believed to be "abstract", "object-centered", and "conversed". These are the decisive factors for the existence of the differences in language expressing. It is of great importance to study these differences and make some adjustments in terms of syntactic structure, semantic focus, and time order so as to achieve a natural rending.
基金Supported by the National Natural Science Foundation of China(10661006) Supported by the New Century Guangxi Ten-hundred-thousand Talents Project(2005214)
文摘In this paper,we establish an invariance principle for ρ^--mixing random sequences under some moment condition.The result improve and extend the relevant result of Wu(2003).
文摘The land issue remains a colonial legacy which Africa must resolve to facilitate the region's Before colonialism land was considered by communities as economic rather than a socio-economic advancements political resource. Agricultural communities vacated land no longer fertile or useful for pasture. Conflicts over parcels of land were therefore rare and if they did occur often resulted in migration. Scramble over parcels of land was thus for need. However, with European scramble and arbitrary partition of Africa in the nineteenth century, formal boundaries were established by colonialists between colonies, a policy later pursued by colonial administrators between communities within colonies. Colonial policies and decolonization process in some colonies complicated the land problem, resulting in the scramble over land for greed by the newly independent states and communities. Land scrambled for greed engendered generalized conflicts. This paper thus intends to argue that the scramble over land for greed made land more a factor of contention than peace in Africa. A chronological-illustrative method, with references from the different geographical divide in Africa was adopted to explore the changing land usage and faces of land conflicts in Africa with the finality that land question in the region is largely a colonial problem.
文摘Fiumara d'arte is an open-air museum of sculpture and contemporary art. Among the art-works of Fiumara d'arte, the Pyramid is the last one in order of time. It is a monumental sculpture made of COR-TEN steel, by the artist Mauro Staccioli and it is located on one specific point of the 38th parallel of latitude, on a hill of the northern mountains of Sicily. In this study the architectural and engineering features of land art-works built in this particular plein-air park are examined and discussed. After a general description of Fiumara d'Arte and its significance in the territory, the case of the Pyramid on the 38th parallel is focalized and a discussion of its architectural, artistic and environmental values is reported. Moreover the structural implications in its design and construction are explained, while the worst effects of external actions are underlined by showing the results of the analysis performed on a finite element model of the whole structure.
基金supported by the National Natural Science Foundation of China under Grant No. 61172067
文摘We consider the spectrum handoff delay of a Secondary User(SU)in cognitive radio networks.We propose a spectrum handoff scheme based on Recommended Channel Sensing Sequence(RCSS),which aims to optimise the spectrum handoff delay subject to the sensing reliability and link maintenance constraints.There are two cases that should be considered:1)the SU performs spectrum handoff successfully during the current frame,and 2)the SU successfully performs the spectrum handoff using several frames.We develop a dynamic programming algorithm for RCSS to identify the optimal sensing sequence for the first case,and an updating algorithm for RCSS to improve the handoff performance for the second case.The numerical results confirm that the proposed RCSS handoff scheme can achieve better handoff delay performance than others when the received signal-to-noise ratios of the Pus' signals on different channels are non-identical.
基金supported by a grant from the National Key Technology R&D Program in the Eleventh"Five-year Plan"Period ( 20070403-2006BAC01B03-02-02)fund for earthquake research (200708020),China
文摘The enumerating algorithm has been introduced into the fitting procedure of the ASR model. Based on the detailed study of 21 large earthquakes with M≥6. 8 in the Chinese Mainland,the statistical features of seismic strain release before large earthquakes have been summarized. In the mass,the strain release models can be divided into five types. The first is the DA model,in which the strain release accelerates in broader areas and decelerates in small areas around the epicenter. Approximately 38% of earthquake samples are of this type. The second is the AD model,in which the strain release decelerates in broader areas and accelerates in smaller areas around the epicenter with an occupying ratioof approximately 19%. The third is ASR,in which only accelerating strain release can be observed. Cases of this model amount to about 14%. The fourth is DSR,in which only decelerating strain release can be checked,amounting to about 24%. There is only one earthquake sample of the fifth type (LSR),which shows a linear strain release. There is a 3~6 years difference in the duration of pre-shock sequences between the accelerating and decelerating models. This means that seismic quiescence against a background of increased seismicity of small earthquakes before large earthquakes are a typical feature in general. For the DA model,the average size of critical regions for steady accelerating and decelerating strain release is about 260km to 400km and 100km to 200km,respectively,3 to 5 times and 1 to 2 times the rupture size of an earthquake of magnitude 7. 0. The AD model is the opposite of the DA model. The model parameter,m value,has good stability. The ratio of ASR is about the same for accelerating seismic strain release phenomena,no matter what the strain release models are,or how large the strain release quantity is. With regard to decelerating seismic strain release phenomena, the DA model has the most distinctive decelerating strain release characteristic and is the typical feature of seismic strain release,i. e. "decelerating in-accelerating out seismic strain model".
文摘Reading comprehension plays a vital role in English teaching and learning. It's impossible to learn English without reading. So for many years, English teachers have been engaging themselves in the research of teaching reading effectively and they have proposed useful ways of teaching reading, such as bottom-up and top-down. Recently, the research in native English readers has shown that teaching of the text structure can facilitate first language reading. Based on the research in native English reading, the author carries out the research where top-level structure is applied to 'New Horizon College English'. The basic approaches in this essay are 'cause—effect' 'problem—solution' and 'time sequence'. The practice has proved that the application of top-level structure can guide the readers to build up the awareness of text structure and it can help the students overcome language and cultural barriers.
文摘The extreme modern elevation of the Tianshan Mountains reflects the Cenozoic deformation. Apatite Fission Track (AFI) chronometry is widely used to study the latest cooling stages caused by tectonic process or by exhumation in the uppermost crust. However, uncertainties remain over timing constraints on thermal history of the Tianshan Mountains since the Cenozoic though a great mount of dating work had been done in this area. To address this issue, modern river sands from the drainage basin on the piedmont of the Tianshan Mountains were sampled to integrate regional information. Single grains were dated with the AFT method, and then different grain-age components were identified to provide thermochronological constraints of their sources. Combined with discussion of previous dataset, our results show the multi-staged rapid cooling cluster at 46-32, 25-24, 19-13, 8-6, and -3 Ma, respectively. We interpreted these cooling events as a result of interplays between the Cenozo- ic tectonic uplift of the mountains and regional climate change.