A study was conducted in the forest-steppe region of the Loess Plateau to provide insight into the factors affecting the process of vegetation establishment,and to provide recommendations for the selection of indigeno...A study was conducted in the forest-steppe region of the Loess Plateau to provide insight into the factors affecting the process of vegetation establishment,and to provide recommendations for the selection of indigenous species in order to speed up the succession process and to allow the establishment of vegetation more resistant to soil erosion.Four distinctive vegetation types were identified,and their distribution was affected not only by the time since abandonment but also by other environmental factors,mainly soil water and total P in the upper soil layers.One of the vegetation types,dominated by Artemisia scoparia,formed the early successional stage after abandonment while the other three types formed later successional stages with their distribution determined by the soil water content and total P.It can be concluded that the selection of appropriate species for introduction to accelerate succession should be determined by the local conditions and especially the total P concentration and soil water content.展开更多
Optimization under uncertainty is a challenging topic of practical importance in the Process Systems Engineering.Since the solution of an optimization problem generally exhibits high sensitivity to the parameter varia...Optimization under uncertainty is a challenging topic of practical importance in the Process Systems Engineering.Since the solution of an optimization problem generally exhibits high sensitivity to the parameter variations, the deterministic model which neglects the parametric uncertainties is not suitable for practical applications. This paper provides an overview of the key contributions and recent advances in the field of process optimization under uncertainty over the past ten years and discusses their advantages and limitations thoroughly. The discussion is focused on three specific research areas, namely robust optimization, stochastic programming and chance constrained programming, based on which a systematic analysis of their applications, developments and future directions are presented. It shows that the more recent trend has been to integrate different optimization methods to leverage their respective superiority and compensate for their drawbacks. Moreover, data-driven optimization, which combines mathematical programming methods and machine learning algorithms, has become an emerging and competitive tool to handle optimization problems in the presence of uncertainty based on massive historical data.展开更多
Accompanying the development of social economy,the land use model of mountainous area,typically eco-weak area,is changing gradually. Here the establishment of eco-friendly land use model in mountainous area,will pione...Accompanying the development of social economy,the land use model of mountainous area,typically eco-weak area,is changing gradually. Here the establishment of eco-friendly land use model in mountainous area,will pioneer the model of sustainable development in that area. Concerning Qianjiang District of Chongqing Municipality,huge change of land use model,mainly embodied in the unceasing increase of construction land and gradual decrease of agricultural use land,has taken place in recent years. To explore the eco-friendly land use model in mountainous area,Qianjiang District was chosen as the study object in the present study. Via analyzing the changes in land use model,we found that related eco-environment restrictive factors mainly regional climatic change,soil texture,hydrological environment as well as soil erosion and land degradation,etc. And based on these results,we further analyzed the effect of land use change on eco-environment and the factors restricting the maintenance of eco-environment and regional development,finally put forward the counter measures for balancing land use and co-environment in mountainous area. The results will be important for the development of social economy and eco-system construction in Qianjiang District.展开更多
We quantified microhabitat use by white-footed mice Peromyscus leucopus in forest and old-field habitats occupied by Morrow' s honeysuckle Lonicera morrowii, an invasive exotic shrub imported from Japan. Microhabitat...We quantified microhabitat use by white-footed mice Peromyscus leucopus in forest and old-field habitats occupied by Morrow' s honeysuckle Lonicera morrowii, an invasive exotic shrub imported from Japan. Microhabitat characteristics were compared between trails used by mice ( n = 124) and randomly selected trails ( n = 127) in 4 study plots located at Fort Necessity National Battlefield, Farmington, Pennsylvania, USA. We compared 10 mierohabitat variables between used and random trails using non-metric multidimensional scaling (NMDS) and classification and regression tree (CART) analysis. Trails used by mice were statistically different from randomly selected trails in both forested plots ( P 〈 0. 008) and old-field plots ( P 〈 0. 001 ). In the forested plots, trails of white-footed mice were more often associated with a greater percent cover (% cover) of coarse woody debris (CWD) than were randomly selected trails. In the old-field plots, mouse trails were commonly characterized by having a lower % cover of exotic herbaceous vegetation, a greater % cover of shrubs, and a greater % cover of Morrow' s honeysuckle than randomly selected trails. Our study indicates that white-footed mice do not move randomly and prefer areas of high structural complexity, thereby showing significant microhabitat preference. The preference of white-footed mice for areas with a relatively high percent cover of Morrow's honeysuckle could 1 ) be a factor in the aggressive nature of the exotic honeysuckle shrub's spread throughout the Battlefield or 2) cause the shrub to spread even faster into adjacent areas not yet occupied by Morrow' s honeysuckle展开更多
Based on DNA extraction and optimization of random amplified reaction (RAPD) to the gametophytes and sporophytes of Kelp “901” strain, genetic study on variation was conducted to its parents and offsprings of F6, F7...Based on DNA extraction and optimization of random amplified reaction (RAPD) to the gametophytes and sporophytes of Kelp “901” strain, genetic study on variation was conducted to its parents and offsprings of F6, F7, F8, and F9 generation. RAPD results have shown that among 30 selected primers for gametophytes, 297 loci ranging from 200 to 3 000 bp were obtained in the average of 9.9 loci for each primer. This indicated a high polymorphic rate with RAPD detection. UPGMA (unweighted pair-group method arithmetic average) analysis showed that each male and female gametophyte of a generation could be clustered into one pair separately. The genetic distances of the Kelp 901 generation were 0.321 2–0.476 7, and the maximum was between F7 and F8 (0.476 7). Identity analysis showed that F6 generation was more close to the female parent (0.659 3), and F7 generation was more close to the male parent (0.578 8). To the sporophytes study in 24 selected primers for RAPD amplification, 191 loci ranging from 230-2 800 bp were obtained, in the average to each primer of 8.0 loci. The heterozygosity to six populations were male parent (0.223 9), female parent (0.107 2), F6 (0.216 4), F7 (0.228 6), F8 (0.229 6) and F9 (0.317 2). The nearest genetic distance was 0.083 5 (F8, F9). Total heterozygosity (HT) of F6, F7, F8 and F9 generations was 0.318 6, the average heterozygosity (HS) for F6, F7, F8 and F9 generations was 0.248 0, and deduced coefficient of population differentiation (Gst ) was 22.2%. Six sequence characterized amplified regions (SCAR) were preliminary screened through RAPD analysis. It needed to be verified in detail as they are significant for molecular marker assistance in breeding and selecting Laminaria.展开更多
Tidal rivers are intrinsically complex because tidal propagation is influenced by river discharge. This study aims to examine the seasonal variation of tidal prism and energy variance in the tidal river of the Changji...Tidal rivers are intrinsically complex because tidal propagation is influenced by river discharge. This study aims to examine the seasonal variation of tidal prism and energy variance in the tidal river of the Changjiang(Yangtze) River estuary in China. In order to quantify the behaviour of river and tide,we use numerical modelling that has been validated using measured data. We conduct our analysis by quantifying the discharge and energy variance in separate components for both the river and the tide,during wet and dry seasons. We note various definitions of tidal prism and explore the difference between tidal discharge on the flood and ebb and tidal storage volume. The results show that the river discharge attenuates the tidal motion and reduces the tidal flood discharge but the tidal storage volume is approximately constant with different riverine discharge since part of the fresh water discharge is intercepted and captured in the estuary due to the backwater effect. It appears that the tidal discharge adjusts according to the variation of river discharge to keep a constant tidal storage volume. An analysis of the hydraulics shows that the transition from tidal dominance(at the mouth) to river dominance(upstream) depends on the location of tidal current reversal which varies from wet season to dry season. Duringthe wet season,the Changjiang River estuary is totally dominated by energy from fresh water discharge.展开更多
Freeze drying has a deleterious effect on the viability of microorganisms. In front of this difficulty, the present study adopts response surface methodology to optimize the chemical compositions of protective agents ...Freeze drying has a deleterious effect on the viability of microorganisms. In front of this difficulty, the present study adopts response surface methodology to optimize the chemical compositions of protective agents to seek for maximum viability of Bifidobacterium longum BIOMA 5920 during freeze-drying. Through the compara- tive analysis of single protectant, the complex protective agents show better effect on the Bifidobacterium viability. Human-like collagen (HLC), trehalose and glycerol are confirmed as significant factors by Box-Behnken Design. The optimized formula for these three variables is tested as follows: HLC 1.23%, trehalose 11.50% and glycerol 4.65%. Under this formula, the viability is 88.23%, 39.67% higher in comparison to the control. The viable count is 1.07×10 9 cfu·g-1 , greatly exceeding the minimum viable count requirement (10 6 cfu·g-1 ).展开更多
There are five changes in higher education across the world in the 21st century. The five changes include changes in the university students, changes in the professoriate, changes in academic administration, intematio...There are five changes in higher education across the world in the 21st century. The five changes include changes in the university students, changes in the professoriate, changes in academic administration, intemationalisation, and assessment of academic work. These changes are evident in higher education in China. The pressure of the changes -on lecturers will have effects on the wellbeing of lecturers. The study discusses the wellbeing under the Self-determination Theory. This theory views wellbeing as a state of happiness. This theory also proposes that people's intrinsic goals like personal growth, meaningful relationships, and community contributions can enhance the satisfaction of three basic needs--need for autonomy, need for competence, and need for relatedness. In this way, lecturers can experience a sense of wellbeing. The findings of the study are significant for leaders in higher education who need to implement policies that foster effective work environments.展开更多
Gas-particle two-phase flow is a very important consideration in designing various machines. Although a great deal of theoretical, experimental, and numerical research has been carried out, particle motion in a supers...Gas-particle two-phase flow is a very important consideration in designing various machines. Although a great deal of theoretical, experimental, and numerical research has been carried out, particle motion in a supersonic flow has not been sufficiently clarified. Hence, in order to clarify the interactions between flow and particles, the authors consider the characteristics of particle motion, especially at high temperatures. In the present study, the flow of a gas with a diluted particle load is to be simulated in a conventional converging-diverging supersonic nozzle. The turbulent gas flow in the nozzle is computed with the finite difference and RANS (raynolds averaged navier-stokes simulation) methods. The particle motion is simulated in a Lagrangian manner. In addition, taking into account the light particle loading, a weak coupling method is used. Through this investigation, it is shown that the particle velocity increases monotonically from the nozzle throat to the outlet. And it is shown that particles can be accelerated to higher velocities in helium than in nitrogen, and smaller particles tend to attain higher speed and lower static temperature.展开更多
The increasing awareness of climate change has led organizations to demand a standard procedure to measure and communicate greenhouse gas(GHG) emissions linked to their products or services.The publicly available spec...The increasing awareness of climate change has led organizations to demand a standard procedure to measure and communicate greenhouse gas(GHG) emissions linked to their products or services.The publicly available specification PAS 2050 has been developed in response to broad community and industry desire for a consistent method-carbon footprint for assessing the life cycle GHG emissions of goods and services.Specifically,this paper illustrates the implementation of carbon footprint for a baby stroller in accordance with PAS 2050.A fial value of 321 kg per one stroller including package was calculated.Moreover,the study led to identify raw materials production of the stroller as the main source of GHS emissions where efforts need to focus for emission reduction opportunities.This case study is hoped to be a starting point for organizations to benefit from the increasing application of carbon footprint assessment.展开更多
High-precision isotope composition determinations using multicollector, magnetic-sector induc- tively coupled plasma mass spectrometry (MC-ICPMS) have recently revealed that some transition metal isotopes such as thos...High-precision isotope composition determinations using multicollector, magnetic-sector induc- tively coupled plasma mass spectrometry (MC-ICPMS) have recently revealed that some transition metal isotopes such as those of Mo, Fe, Cu, Zn etc. can be used as biogeochemical tracers in global change research. The Mo isotope system may be useful in paleoredox investigations indicating that δ97/95Mo in seawater may co-vary with changes in the relative proportions of anoxic and oxic sedimentation in the ocean, and that this variation may be recorded inδ97/95Mo of anoxic sediments. The Mo continental flux into the oceans and the global Mo isotope budget can be estimated fromδ97/95Mo values. The Fe isotope composition in seawater is an important issue because Fe plays a controlling role in biological productivity in the oceans and its abundance in seawater may have substantial effect on climate changes. Iron isotope fractionations could result from bio- and abio-processes and have about 0.1% variation (δ56/54Fe), so Fe isotopes considered alone cannot be used to distinguish the products of abiotic and biotic Fe processing in geological records. Cu and Zn isotopes are also used as biogeochemical tracers, but the researches are relatively less. This review mainly focuses on the methods for preparation, purification and determination of new isotope tracer samples, and on isotope applications in marine environmental changes.展开更多
Population fluctuation of oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), was monitored by using methyl eugenol traps during May, 2011 to December, 2011 and May, 2016 to December, 2016 ...Population fluctuation of oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), was monitored by using methyl eugenol traps during May, 2011 to December, 2011 and May, 2016 to December, 2016 in mango orchard farms of Department of Agricultural Research in Yezin, Myanmar. In 2011, the highest mean number of male oriental fruit flies/trap/day (241.42 ± 11.79) was recorded in June and the lowest (2.21 ± 0.40) in December. The highest mean number of male oriental frui t flies/trap/day (388.95 ± 8.56) was recorded in the month of June and the lowest (2.33 ± 0.20) in December, 2016. Population data were correlated with meteorological data including temperature, duration of sunshine, and rainfall. Population fluctuation of male fruit flies was positively correlated with temperature and rainfall, and negatively correlated with the duration of sunshine.展开更多
We analyze the effect of stochastic dephasing on geometric phases. The result implies that the correction of geometric phases relies on not only the fluctuation of the random variable in the stochastic process, but al...We analyze the effect of stochastic dephasing on geometric phases. The result implies that the correction of geometric phases relies on not only the fluctuation of the random variable in the stochastic process, but also the frequency of the system.展开更多
In order to gain a more comprehensive understanding of institutional change, researchers need to go beyond a snapshot view of significant events but consider events in their temporal setting. Pierson (2004) advocate...In order to gain a more comprehensive understanding of institutional change, researchers need to go beyond a snapshot view of significant events but consider events in their temporal setting. Pierson (2004) advocated that the events that lead to institutional change should be placed in a moving temporal context, as this will not only add to our comprehension of the dynamics of change, but also enrich the existing research and enhance the theories we employ to give meaning to these events. Pierson (2004) laid the foundation for the research that was later developed by Thelen (2009) that considered incremental endogenous shifts in institutional thinking that can often result in fundamental transformations. The central issues of Pierson's (2004) thesis lay in his interpretation of history and its relationship with path dependence. He claimed that once an institution has chosen a particular path to follow, it can become locked into that pathway and so the options of choice are restricted. This then presumed that an institutions first choice of action is crucial to whether they become locked into a successful course of action or not. The result of the first choice being successful or not would be dependent on the presence of increasing returns. The explication Pierson proffers of increasing returns is different to an economic one in that it is based on positive feedback processes and politics in time. The implications of Pierson's work and those that followed have a very serious place in our understanding of institutional change.展开更多
In this secondary research, published works on effect of climate change on water resources in other countries and in Australia were reviewed critically. Research question, objectives and assumptions were made to facil...In this secondary research, published works on effect of climate change on water resources in other countries and in Australia were reviewed critically. Research question, objectives and assumptions were made to facilitate this study. First, methods used for such studies and their results at global level were reviewed. Then Australian specific methods of study and findings were reviewed. More commonly, both globally and in Australia, simulations using long-term real data on selected climatic scenarios of global climatic models are projected for long-term future trends. The validity and certainty of predicted occurrences depend upon the closeness of real time data with scenarios to which they are projected. Even with these limitations, projections of already rising temperatures and declining rainfall on surface water and ground water availabilities show gradual decline in water availability leading to water stress both for human communities and ecosystems The role of human-induced emissions in hastening the degradation process has also been investigated. Conserving all available water, practising efficient water consumption and prudent water policies only can provide some relief from what is inevitable.展开更多
The Shelterbelt Forest System Program in northeast, north and northwest China (the Three-North Shelterbelt Program, TNSP) is the largest ecological reforestation program in the world. TNSP vegetation research has im...The Shelterbelt Forest System Program in northeast, north and northwest China (the Three-North Shelterbelt Program, TNSP) is the largest ecological reforestation program in the world. TNSP vegetation research has important ecological meaning and profound social and economic signiifcance. Here, spatio-temporal variation in vegetation cover under the TNSP was examined using the NDVI average method, major climatic factors such as temperature and precipitation, and linear regression trend analysis from 1982 to 2006. We found that in the past 25 years, NDVI vegetation in the study area has consistently risen at a rate of 0.007 per decade. Vegetation cover, temperature and precipitation are positively correlated. The area of vegetation associated with precipitation is larger than the area related to temperature;precipitation is the key factor affecting vegetation growth across the TNSP. From 1982 to 2006, regions with improved vegetation cover were found in the central and southern part of the Greater Khingan Mountains, central part of the Lesser Khingan Mountains, northeastern part of the Changbai Mountains, Yanshan Mountians, Western Liaoning Hilly Region, Altai Mountains, Tien Shan Mountains, eastern part of the Qilian Mountains, eastern part of the northwest desert as wel as southern part of the Gul y Region of the Loess Plateau. However, vegetation cover declined on both sides of the Greater Khingan Mountains, western part of the Hulun Buir Plateau, northern part of the Sanjiang Plain, southern part of Horqin Sandy Land, southern part of the northwest desert and northern part of the Gul y Region of the Loess Plateau.展开更多
The Qinghai-Tibetan Plateau is the highest biogeographic unit on earth and widely regarded as its ‘third pole'.The high-altitude,frigid and arid alpine ecosystems that form the Plateau are extremely sensitive to cli...The Qinghai-Tibetan Plateau is the highest biogeographic unit on earth and widely regarded as its ‘third pole'.The high-altitude,frigid and arid alpine ecosystems that form the Plateau are extremely sensitive to climate change and human disturbance.Unsurprisingly,the Plateau is therefore a global epicenter of ecological and global change research and provides the ideal conditions and context to study the impacts of global change.Ecological research conducted on the Plateau can be partitioned into four developmental and chronological phases,beginning with the gathering of primitive knowledge and progressing towards a description of mechanistic processes.Throughout the course of Plateau research paradigm shifts from standalone surveys of biogeographic patterns to fixed monitoring and mechanism research;from isolated population,community and ecosystem approaches to more integrated,multidisciplinary research;and from pure theoretical research to an emphasis on effective resource utilization and sustainable development.Future ecological research will likely pay increasing attention to quantifying the impacts of climate warming and human activity on ecosystem change,and climate and ecosystem feedback processes.Multidisciplinary and comprehensive research should be strengthened amongst fields such as ecosystem ecology,physical geography,environmental science and remote sensing in order to support climate change adaptation and sustainable development in this fragile and unique region.展开更多
This paper investigates a non-Bayesian social learning model, in which each individual updates her beliefs based on private signals as well as her neighbors' beliefs. The private signM is involved in the updating pro...This paper investigates a non-Bayesian social learning model, in which each individual updates her beliefs based on private signals as well as her neighbors' beliefs. The private signM is involved in the updating process through Bayes' rule, and the neighbors' beliefs are embodied in through a weighted average form, where the weights are time-varying. The authors prove that agents eventually have correct forecasts for upcoming signals, and all the beliefs of agents reach a consensus. In addition, if there exists no state that is observationally equivalent to the true state from the point of view of all agents, the authors show that the consensus belief of the whole group eventually reflects the true state.展开更多
基金Project supported by the National Natural Science Foundation of China (Nos.40571094 and 40271074)the Northwest Sci-Technology University of Agriculture and Forestry (No.01140301).
文摘A study was conducted in the forest-steppe region of the Loess Plateau to provide insight into the factors affecting the process of vegetation establishment,and to provide recommendations for the selection of indigenous species in order to speed up the succession process and to allow the establishment of vegetation more resistant to soil erosion.Four distinctive vegetation types were identified,and their distribution was affected not only by the time since abandonment but also by other environmental factors,mainly soil water and total P in the upper soil layers.One of the vegetation types,dominated by Artemisia scoparia,formed the early successional stage after abandonment while the other three types formed later successional stages with their distribution determined by the soil water content and total P.It can be concluded that the selection of appropriate species for introduction to accelerate succession should be determined by the local conditions and especially the total P concentration and soil water content.
文摘Optimization under uncertainty is a challenging topic of practical importance in the Process Systems Engineering.Since the solution of an optimization problem generally exhibits high sensitivity to the parameter variations, the deterministic model which neglects the parametric uncertainties is not suitable for practical applications. This paper provides an overview of the key contributions and recent advances in the field of process optimization under uncertainty over the past ten years and discusses their advantages and limitations thoroughly. The discussion is focused on three specific research areas, namely robust optimization, stochastic programming and chance constrained programming, based on which a systematic analysis of their applications, developments and future directions are presented. It shows that the more recent trend has been to integrate different optimization methods to leverage their respective superiority and compensate for their drawbacks. Moreover, data-driven optimization, which combines mathematical programming methods and machine learning algorithms, has become an emerging and competitive tool to handle optimization problems in the presence of uncertainty based on massive historical data.
文摘Accompanying the development of social economy,the land use model of mountainous area,typically eco-weak area,is changing gradually. Here the establishment of eco-friendly land use model in mountainous area,will pioneer the model of sustainable development in that area. Concerning Qianjiang District of Chongqing Municipality,huge change of land use model,mainly embodied in the unceasing increase of construction land and gradual decrease of agricultural use land,has taken place in recent years. To explore the eco-friendly land use model in mountainous area,Qianjiang District was chosen as the study object in the present study. Via analyzing the changes in land use model,we found that related eco-environment restrictive factors mainly regional climatic change,soil texture,hydrological environment as well as soil erosion and land degradation,etc. And based on these results,we further analyzed the effect of land use change on eco-environment and the factors restricting the maintenance of eco-environment and regional development,finally put forward the counter measures for balancing land use and co-environment in mountainous area. The results will be important for the development of social economy and eco-system construction in Qianjiang District.
基金the National Park Service, U. S. Department of the Interior
文摘We quantified microhabitat use by white-footed mice Peromyscus leucopus in forest and old-field habitats occupied by Morrow' s honeysuckle Lonicera morrowii, an invasive exotic shrub imported from Japan. Microhabitat characteristics were compared between trails used by mice ( n = 124) and randomly selected trails ( n = 127) in 4 study plots located at Fort Necessity National Battlefield, Farmington, Pennsylvania, USA. We compared 10 mierohabitat variables between used and random trails using non-metric multidimensional scaling (NMDS) and classification and regression tree (CART) analysis. Trails used by mice were statistically different from randomly selected trails in both forested plots ( P 〈 0. 008) and old-field plots ( P 〈 0. 001 ). In the forested plots, trails of white-footed mice were more often associated with a greater percent cover (% cover) of coarse woody debris (CWD) than were randomly selected trails. In the old-field plots, mouse trails were commonly characterized by having a lower % cover of exotic herbaceous vegetation, a greater % cover of shrubs, and a greater % cover of Morrow' s honeysuckle than randomly selected trails. Our study indicates that white-footed mice do not move randomly and prefer areas of high structural complexity, thereby showing significant microhabitat preference. The preference of white-footed mice for areas with a relatively high percent cover of Morrow's honeysuckle could 1 ) be a factor in the aggressive nature of the exotic honeysuckle shrub's spread throughout the Battlefield or 2) cause the shrub to spread even faster into adjacent areas not yet occupied by Morrow' s honeysuckle
基金Financially supported by 863 program of China (No.2001AA621090)
文摘Based on DNA extraction and optimization of random amplified reaction (RAPD) to the gametophytes and sporophytes of Kelp “901” strain, genetic study on variation was conducted to its parents and offsprings of F6, F7, F8, and F9 generation. RAPD results have shown that among 30 selected primers for gametophytes, 297 loci ranging from 200 to 3 000 bp were obtained in the average of 9.9 loci for each primer. This indicated a high polymorphic rate with RAPD detection. UPGMA (unweighted pair-group method arithmetic average) analysis showed that each male and female gametophyte of a generation could be clustered into one pair separately. The genetic distances of the Kelp 901 generation were 0.321 2–0.476 7, and the maximum was between F7 and F8 (0.476 7). Identity analysis showed that F6 generation was more close to the female parent (0.659 3), and F7 generation was more close to the male parent (0.578 8). To the sporophytes study in 24 selected primers for RAPD amplification, 191 loci ranging from 230-2 800 bp were obtained, in the average to each primer of 8.0 loci. The heterozygosity to six populations were male parent (0.223 9), female parent (0.107 2), F6 (0.216 4), F7 (0.228 6), F8 (0.229 6) and F9 (0.317 2). The nearest genetic distance was 0.083 5 (F8, F9). Total heterozygosity (HT) of F6, F7, F8 and F9 generations was 0.318 6, the average heterozygosity (HS) for F6, F7, F8 and F9 generations was 0.248 0, and deduced coefficient of population differentiation (Gst ) was 22.2%. Six sequence characterized amplified regions (SCAR) were preliminary screened through RAPD analysis. It needed to be verified in detail as they are significant for molecular marker assistance in breeding and selecting Laminaria.
基金Supported by the National Basic Research Program of China(973 Program)(No.2010CB951204)the National Natural Science Foundation of China(No.44107180)the 111 Project(No.B08022)
文摘Tidal rivers are intrinsically complex because tidal propagation is influenced by river discharge. This study aims to examine the seasonal variation of tidal prism and energy variance in the tidal river of the Changjiang(Yangtze) River estuary in China. In order to quantify the behaviour of river and tide,we use numerical modelling that has been validated using measured data. We conduct our analysis by quantifying the discharge and energy variance in separate components for both the river and the tide,during wet and dry seasons. We note various definitions of tidal prism and explore the difference between tidal discharge on the flood and ebb and tidal storage volume. The results show that the river discharge attenuates the tidal motion and reduces the tidal flood discharge but the tidal storage volume is approximately constant with different riverine discharge since part of the fresh water discharge is intercepted and captured in the estuary due to the backwater effect. It appears that the tidal discharge adjusts according to the variation of river discharge to keep a constant tidal storage volume. An analysis of the hydraulics shows that the transition from tidal dominance(at the mouth) to river dominance(upstream) depends on the location of tidal current reversal which varies from wet season to dry season. Duringthe wet season,the Changjiang River estuary is totally dominated by energy from fresh water discharge.
基金Supported by the National High Technology Research and Development Program of China (2007AA03Z456)the National Natural Science Foundation of China (20776119, 21076169 and 31000019)+5 种基金the Xi’an Research and Development Program(NC08005, YF07078)the Scientific Research Program of Shaanxi Provincial Department of Education,China(08JK452,08JK453,JG08181,2010JC21,2010JS107,2010JS108, 2010JK876 and 2010JS109)Shaanxi Provincial Scientific Technology Research and Development Program (2007K06-03, 2010JQ2012, SJ08B03)the Specialized Research Fund for the Doctoral Program of Higher Education of China (20096101120023, 20096101110014)NWU Graduate Innovation and Creativity Funds (08YSY17)Shaanxi Key Subject Program, China
文摘Freeze drying has a deleterious effect on the viability of microorganisms. In front of this difficulty, the present study adopts response surface methodology to optimize the chemical compositions of protective agents to seek for maximum viability of Bifidobacterium longum BIOMA 5920 during freeze-drying. Through the compara- tive analysis of single protectant, the complex protective agents show better effect on the Bifidobacterium viability. Human-like collagen (HLC), trehalose and glycerol are confirmed as significant factors by Box-Behnken Design. The optimized formula for these three variables is tested as follows: HLC 1.23%, trehalose 11.50% and glycerol 4.65%. Under this formula, the viability is 88.23%, 39.67% higher in comparison to the control. The viable count is 1.07×10 9 cfu·g-1 , greatly exceeding the minimum viable count requirement (10 6 cfu·g-1 ).
文摘There are five changes in higher education across the world in the 21st century. The five changes include changes in the university students, changes in the professoriate, changes in academic administration, intemationalisation, and assessment of academic work. These changes are evident in higher education in China. The pressure of the changes -on lecturers will have effects on the wellbeing of lecturers. The study discusses the wellbeing under the Self-determination Theory. This theory views wellbeing as a state of happiness. This theory also proposes that people's intrinsic goals like personal growth, meaningful relationships, and community contributions can enhance the satisfaction of three basic needs--need for autonomy, need for competence, and need for relatedness. In this way, lecturers can experience a sense of wellbeing. The findings of the study are significant for leaders in higher education who need to implement policies that foster effective work environments.
文摘Gas-particle two-phase flow is a very important consideration in designing various machines. Although a great deal of theoretical, experimental, and numerical research has been carried out, particle motion in a supersonic flow has not been sufficiently clarified. Hence, in order to clarify the interactions between flow and particles, the authors consider the characteristics of particle motion, especially at high temperatures. In the present study, the flow of a gas with a diluted particle load is to be simulated in a conventional converging-diverging supersonic nozzle. The turbulent gas flow in the nozzle is computed with the finite difference and RANS (raynolds averaged navier-stokes simulation) methods. The particle motion is simulated in a Lagrangian manner. In addition, taking into account the light particle loading, a weak coupling method is used. Through this investigation, it is shown that the particle velocity increases monotonically from the nozzle throat to the outlet. And it is shown that particles can be accelerated to higher velocities in helium than in nitrogen, and smaller particles tend to attain higher speed and lower static temperature.
基金financially and technically supported by Bugaboo (Xiamen) Companythe Fundamental Research Funds No. 2010121035 for the Central Universities of China
文摘The increasing awareness of climate change has led organizations to demand a standard procedure to measure and communicate greenhouse gas(GHG) emissions linked to their products or services.The publicly available specification PAS 2050 has been developed in response to broad community and industry desire for a consistent method-carbon footprint for assessing the life cycle GHG emissions of goods and services.Specifically,this paper illustrates the implementation of carbon footprint for a baby stroller in accordance with PAS 2050.A fial value of 321 kg per one stroller including package was calculated.Moreover,the study led to identify raw materials production of the stroller as the main source of GHS emissions where efforts need to focus for emission reduction opportunities.This case study is hoped to be a starting point for organizations to benefit from the increasing application of carbon footprint assessment.
基金Project supported by Qingdao special project for outstanding young scientists (04-3-JJ-03), "100 Talents Project " and the Science Innovation Key Projects of the Chinese Academy of Sciences (No. KZCX1-SW- 01-08) and the National Science Foundation for Young Scientists of China (No.49925614).
文摘High-precision isotope composition determinations using multicollector, magnetic-sector induc- tively coupled plasma mass spectrometry (MC-ICPMS) have recently revealed that some transition metal isotopes such as those of Mo, Fe, Cu, Zn etc. can be used as biogeochemical tracers in global change research. The Mo isotope system may be useful in paleoredox investigations indicating that δ97/95Mo in seawater may co-vary with changes in the relative proportions of anoxic and oxic sedimentation in the ocean, and that this variation may be recorded inδ97/95Mo of anoxic sediments. The Mo continental flux into the oceans and the global Mo isotope budget can be estimated fromδ97/95Mo values. The Fe isotope composition in seawater is an important issue because Fe plays a controlling role in biological productivity in the oceans and its abundance in seawater may have substantial effect on climate changes. Iron isotope fractionations could result from bio- and abio-processes and have about 0.1% variation (δ56/54Fe), so Fe isotopes considered alone cannot be used to distinguish the products of abiotic and biotic Fe processing in geological records. Cu and Zn isotopes are also used as biogeochemical tracers, but the researches are relatively less. This review mainly focuses on the methods for preparation, purification and determination of new isotope tracer samples, and on isotope applications in marine environmental changes.
文摘Population fluctuation of oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), was monitored by using methyl eugenol traps during May, 2011 to December, 2011 and May, 2016 to December, 2016 in mango orchard farms of Department of Agricultural Research in Yezin, Myanmar. In 2011, the highest mean number of male oriental fruit flies/trap/day (241.42 ± 11.79) was recorded in June and the lowest (2.21 ± 0.40) in December. The highest mean number of male oriental frui t flies/trap/day (388.95 ± 8.56) was recorded in the month of June and the lowest (2.33 ± 0.20) in December, 2016. Population data were correlated with meteorological data including temperature, duration of sunshine, and rainfall. Population fluctuation of male fruit flies was positively correlated with temperature and rainfall, and negatively correlated with the duration of sunshine.
基金The project supported by National Natural Science Foundation of China under Grant No.60573008
文摘We analyze the effect of stochastic dephasing on geometric phases. The result implies that the correction of geometric phases relies on not only the fluctuation of the random variable in the stochastic process, but also the frequency of the system.
文摘In order to gain a more comprehensive understanding of institutional change, researchers need to go beyond a snapshot view of significant events but consider events in their temporal setting. Pierson (2004) advocated that the events that lead to institutional change should be placed in a moving temporal context, as this will not only add to our comprehension of the dynamics of change, but also enrich the existing research and enhance the theories we employ to give meaning to these events. Pierson (2004) laid the foundation for the research that was later developed by Thelen (2009) that considered incremental endogenous shifts in institutional thinking that can often result in fundamental transformations. The central issues of Pierson's (2004) thesis lay in his interpretation of history and its relationship with path dependence. He claimed that once an institution has chosen a particular path to follow, it can become locked into that pathway and so the options of choice are restricted. This then presumed that an institutions first choice of action is crucial to whether they become locked into a successful course of action or not. The result of the first choice being successful or not would be dependent on the presence of increasing returns. The explication Pierson proffers of increasing returns is different to an economic one in that it is based on positive feedback processes and politics in time. The implications of Pierson's work and those that followed have a very serious place in our understanding of institutional change.
文摘In this secondary research, published works on effect of climate change on water resources in other countries and in Australia were reviewed critically. Research question, objectives and assumptions were made to facilitate this study. First, methods used for such studies and their results at global level were reviewed. Then Australian specific methods of study and findings were reviewed. More commonly, both globally and in Australia, simulations using long-term real data on selected climatic scenarios of global climatic models are projected for long-term future trends. The validity and certainty of predicted occurrences depend upon the closeness of real time data with scenarios to which they are projected. Even with these limitations, projections of already rising temperatures and declining rainfall on surface water and ground water availabilities show gradual decline in water availability leading to water stress both for human communities and ecosystems The role of human-induced emissions in hastening the degradation process has also been investigated. Conserving all available water, practising efficient water consumption and prudent water policies only can provide some relief from what is inevitable.
基金National Natural Science Foundation of China(4117111640961038)
文摘The Shelterbelt Forest System Program in northeast, north and northwest China (the Three-North Shelterbelt Program, TNSP) is the largest ecological reforestation program in the world. TNSP vegetation research has important ecological meaning and profound social and economic signiifcance. Here, spatio-temporal variation in vegetation cover under the TNSP was examined using the NDVI average method, major climatic factors such as temperature and precipitation, and linear regression trend analysis from 1982 to 2006. We found that in the past 25 years, NDVI vegetation in the study area has consistently risen at a rate of 0.007 per decade. Vegetation cover, temperature and precipitation are positively correlated. The area of vegetation associated with precipitation is larger than the area related to temperature;precipitation is the key factor affecting vegetation growth across the TNSP. From 1982 to 2006, regions with improved vegetation cover were found in the central and southern part of the Greater Khingan Mountains, central part of the Lesser Khingan Mountains, northeastern part of the Changbai Mountains, Yanshan Mountians, Western Liaoning Hilly Region, Altai Mountains, Tien Shan Mountains, eastern part of the Qilian Mountains, eastern part of the northwest desert as wel as southern part of the Gul y Region of the Loess Plateau. However, vegetation cover declined on both sides of the Greater Khingan Mountains, western part of the Hulun Buir Plateau, northern part of the Sanjiang Plain, southern part of Horqin Sandy Land, southern part of the northwest desert and northern part of the Gul y Region of the Loess Plateau.
文摘The Qinghai-Tibetan Plateau is the highest biogeographic unit on earth and widely regarded as its ‘third pole'.The high-altitude,frigid and arid alpine ecosystems that form the Plateau are extremely sensitive to climate change and human disturbance.Unsurprisingly,the Plateau is therefore a global epicenter of ecological and global change research and provides the ideal conditions and context to study the impacts of global change.Ecological research conducted on the Plateau can be partitioned into four developmental and chronological phases,beginning with the gathering of primitive knowledge and progressing towards a description of mechanistic processes.Throughout the course of Plateau research paradigm shifts from standalone surveys of biogeographic patterns to fixed monitoring and mechanism research;from isolated population,community and ecosystem approaches to more integrated,multidisciplinary research;and from pure theoretical research to an emphasis on effective resource utilization and sustainable development.Future ecological research will likely pay increasing attention to quantifying the impacts of climate warming and human activity on ecosystem change,and climate and ecosystem feedback processes.Multidisciplinary and comprehensive research should be strengthened amongst fields such as ecosystem ecology,physical geography,environmental science and remote sensing in order to support climate change adaptation and sustainable development in this fragile and unique region.
基金supported by the National Natural Science Foundation of China under Grant Nos.61074125 and 61104137the Science Fund for Creative Research Groups of the National Natural Science Foundation of China under Grant No.61221003the National Key Basic Research Program (973 Program) of China under Grant No.2010CB731403
文摘This paper investigates a non-Bayesian social learning model, in which each individual updates her beliefs based on private signals as well as her neighbors' beliefs. The private signM is involved in the updating process through Bayes' rule, and the neighbors' beliefs are embodied in through a weighted average form, where the weights are time-varying. The authors prove that agents eventually have correct forecasts for upcoming signals, and all the beliefs of agents reach a consensus. In addition, if there exists no state that is observationally equivalent to the true state from the point of view of all agents, the authors show that the consensus belief of the whole group eventually reflects the true state.