Traditionally,patch-based analysis at the landscape scale fragmentation has been used in the study of landscape ecology while the study of boundary and node has not been considered as much detail until recently.This s...Traditionally,patch-based analysis at the landscape scale fragmentation has been used in the study of landscape ecology while the study of boundary and node has not been considered as much detail until recently.This study investigated the possibility of applying boundary-and node-based methods in landscape pattern analysis to the upper reaches of the Minjiang River in the southwestern China.Boundary-based and node-based landscape indices were selected to be used in analyzing changes in landscape patterns,and the results were compared with analysis using traditional pattern indices.We compared the responses of patch-area-based,boundary-length-based and node-number-based indices,and concluded that boundary-based and node-based indices are more sensitive to disturbance than patch-based indices with various patterns,and node-based indices are even more sensitive than boundary-based ones.Thus,the results suggest that boundary-based and node-based pattern analysis methods provide helpful supplementary information to traditional patch-based pattern analysis methods.The results about pattern dynamics of landscapes in the upper reaches of the Minjiang River based on boundaries and nodes showed that with human disturbance,the dominance of forest landscape was weakened by other landscape types;thus the landscape pattern of the study area became more homogeneous and the boundary network became more complex.These changes further augmented disturbance interfaces in the landscape and increased the possibilities of further landscape fragmentation.展开更多
To understand the responses of a freshwater ecosystem to the impoundment of the Three Gorges Reservoir (TGR), phytoplankton was monitored in the tributaries of the TGR area. From August 2010 to July 2011, algal spec...To understand the responses of a freshwater ecosystem to the impoundment of the Three Gorges Reservoir (TGR), phytoplankton was monitored in the tributaries of the TGR area. From August 2010 to July 2011, algal species composition, abundance, chlorophyll a and other environmental parameters were investigated in the Gaolan River, which is a tributary of Xiangxi River. Thirty-one algal genera from seven phyla were identified. Results show that the lowest concentrations of total phosphorus (TP) and total nitrogen (TN) were 0.06 mg/L and 1.08 rag/L, respectively. The values of TP and TN exceeded the threshold concentration of the eutrophic state suggested for freshwater bodies. In the Gaolan River, the succession of phytoplankton showed clear seasonal characteristics. Different dominant species were observed among seasons under the control of environment factors. In spring and summer, the dominant species were Nitzschia sp. and Aphanizomenon flos-aquae (L.) Ralfs, the limiting nutrient was NO3^--N, and the key environmental factor for phytoplankton population succession was water temperature (WT). In autumn and winter, the dominant species were A.flos-aquae and Chlorella sp., the limiting nutrient was pO3--P, and the key environmental factors were transparency and WT. This study illustrates the influence of physical and chemical factors on phytoplankton seasonal succession in a tributary of TGR since the downstream regions of Xiangxi River and Gaolan River became reservoirs after impoundment of the Three Gorges Dam. We suggest that this activity has significantly affected water quality in the dam area.展开更多
Paracalanus parvus, Paracalanus crassirostris , and Acartia bifilosa are dominant and widely distributed in the Bohai Sea, and comprise an important part of zooplankton in terms of biomass as well as production rate. ...Paracalanus parvus, Paracalanus crassirostris , and Acartia bifilosa are dominant and widely distributed in the Bohai Sea, and comprise an important part of zooplankton in terms of biomass as well as production rate. In order to understand their seasonal distribution and population dynamics, their stage specific abundance in different months of the year were analyzed based on the never analyzed yet samples collected in 1959. The three species showed clear and remarkable seasonal variation in abundance, which maximized in spring and summer, when they formed high biomass patches or concentrations in the nearshore area. For Paracalanus parvus , two peaks were observed in the annual circle, one in June and the other in September. For Paracalanus crassirostris , one peak occurred in summer and a small one in December. The seasonal pattern of Acartia bifilosa was different in different regions. In Bohai Bay it had a two peak pattern, with the first large peak occurring in May and the second one in October. In Laizhou Bay, a winter peak in December and January could be observed besides the spring one. The number of generations during the reproductive season for the three species was estimated based on the annual cycle in abundance and ambient temperature.展开更多
The diversity,community structure and seasonal variation in demersal nekton off the Changjiang(Yangtze)River estuary was evaluated using monthly trawl survey data,collected between December 2008 and November 2009.A to...The diversity,community structure and seasonal variation in demersal nekton off the Changjiang(Yangtze)River estuary was evaluated using monthly trawl survey data,collected between December 2008 and November 2009.A total of 95 species(56 teleosts,11 cephalopods,and 28 decapod crustaceans)from 69 genera,49 families and 15 orders were collected.These species could be classifi ed into six groups on the basis of temporal distribution patterns.The resident crab Ovalipes punctatus dominated the community,both in number and biomass.A clear seasonal succession was observed in the species composition.Cluster analysis revealed three primary seasonal groups corresponding to the samples collected in winter-spring,late spring-summer and late summer-autumn.The highest biomass and lowest diversity were observed in summer,while the lowest biomass and highest diversity in winter.The abundance-biomass comparison curves and community composition suggested that the investigated community was moderately disturbed.The results suggest that reduction in fi shing pressure and in the degree of seasonal hypoxia are essential for sustainable resource management off the Changjiang River estuary.展开更多
Community plays an important role in the preservation of agricultural heritage system (AHS). Recently, many AHS have been valorized as interesting resources for rural tourism. The expectations are that tourism devel...Community plays an important role in the preservation of agricultural heritage system (AHS). Recently, many AHS have been valorized as interesting resources for rural tourism. The expectations are that tourism development (TD) can be supportive for the conservation of AHS while creating benefits for local communities. In this study, two mountainous pilot villages (Longxian and Xiaohuang) in a global conservation project for traditional agricutural systems - Globally Important Agricultural Heritage Systems (GIAHS) were selected to identify the relationship between AHS conservation and TD. The study undertook in-depth interviews, and questionnaires of village residents and informal discussions with local villagers. A t-test and a linear regression model were implemented to explore the comparative dimensions of the two communities with different geographical location, economic situation, and stage of TD. The research found some similarities and differences in the two mountainous communities during AHS conservation and TD. Firstly, AHS are preservaed well in both villages unconsiously, while the residents in Xiaohuang value more highly the heritage elements than the respondents in Longxian, and the villagers in Xiaohuang are more worried about their heritage system; Secondly, both villages expect lots of benefits from TD and they clearly perceive more positive than negative impact from tourism and thus approve TD, while the hugedifferent perception on transportation and accessibility in the two villages reflects the bottleneck of TD in Xiaohuang village. At the same time, the respondents from Xiaohuang perceive more positive and fewer negative impact from tourism than the respondents from Longxian. Thirdly, the respondents in the two villages all show positive attitudes towards participation in tourism mostly motivated by the high income expectation. The main factors to determine the community perception in two villages were also analyzed based on the data process. A location-based coneeputal framework of AHS conservation in partnership with TD at community scale is proposed at the end of the paper. The dynamics of tourism development, that could enhance a better understanding of the complex relationship between conservation objectives and tourism development are discussed.展开更多
Pressure activity data as an important index of gastrointestinal (GI) motility can be obtained from the wireless radiotelemetry capsule. The Hilbert-Huang transform (HHT) method, which is more effective to process...Pressure activity data as an important index of gastrointestinal (GI) motility can be obtained from the wireless radiotelemetry capsule. The Hilbert-Huang transform (HHT) method, which is more effective to process non-stationary signal, is proposed to identify the characteristics of GI motility. We decompose the pressure activity data into intrinsic mode functions (IMFs), calculate the Hi/bert marginal spectrum and attain the peristalsis characteristics of GI tract. The IMFs represent the peristalses modes of GI tract activity embedded in the pressure data. The time-varying characteristic of the method suggests that the HHT is suitable to accommodate other non-stationary biomedical data analysis.展开更多
This work investigates the boreal-summer intraseasonal variability(ISV)of the precipitation over the lower reaches of the Yangtze River basin(LYRB)during 1979–2016,based on daily Climate Prediction Center global prec...This work investigates the boreal-summer intraseasonal variability(ISV)of the precipitation over the lower reaches of the Yangtze River basin(LYRB)during 1979–2016,based on daily Climate Prediction Center global precipitation data.The ISV of the summer monsoon rainfall over the LYRB is mainly dominated by the lower-frequency 12–20-day variability and the higher-frequency 8–12-day variability.The lower-frequency variability is found to be related to the northwestwardpropagating quasi-biweekly oscillation(QBWO)over the western North Pacific spanning the South China Sea(SCS)and Philippine Sea,while the higher-frequency variability is related to the southeastward propagating midlatitude wave train(MLWT).Moreover,not each active QBWO(MLWT)in the SCS(East Asia)can generate ISV components of the precipitation anomaly over the LYRB.The QBWO can change the rainfall significantly with the modulation of mean state precipitation,while the quasi-11-day mode mainly depends on the intensity of the MLWT rather than the mean precipitation change.These findings should enrich our understanding of the ISV of the East Asian summer monsoon and improve its predictability.展开更多
The annual and seasonal trends in pan evaporation in the lower Yellow River Basin based on quality-controlled data from 10 meteorological stations in 1961-2010 are analyzed. The causes for the changes in annual and se...The annual and seasonal trends in pan evaporation in the lower Yellow River Basin based on quality-controlled data from 10 meteorological stations in 1961-2010 are analyzed. The causes for the changes in annual and seasonal pan evaporation are also discussed. The results suggest that, despite the 1.15~C increasing in annual mean surface air temperature over the past 50 years (0.23°C per decade), the annual pan evaporation has steadily declined by an average rate of-7.65 mm per year. By comparison, this change is greater than those previously reported in China. Significant decreasing trends in annual pan evaporation have been observed at almost all stations. As a whole, seasonal pan evaporation decreased significantly, especially in summer, whereas seasonal temperature increased significantly, except in summer. Thus, the pan evaporation paradox exists in the lower Yellow River Basin. The trend analysis of other meteorological factors indicates significant decrease in sunshine duration and wind speed, but no significant variations in precipitation and relative humidity at annual and seasonal time scales. By examining the relationship between precipitation and pan evaporation, it did not show a concurrent decrease in pan evaporation and increase in precipitation. The partial correlation analysis discovered that the primary cause of decrease in annual and seasonal pan evaporation is the decrease in wind speed. A further examination using a stepwise regression shows that decrease in wind speed and sunshine duration, and increase in mean temperature axe likely to be the main meteorological factors affecting the annual and seasonal pan evaporation in the lower Yellow River Basin over the past 50 years.展开更多
With the rapid development of China's tourism market and the gradual improvement of people's pace of life, tourism has become an important way to relax people, so the proportion of tourism consumption in people's d...With the rapid development of China's tourism market and the gradual improvement of people's pace of life, tourism has become an important way to relax people, so the proportion of tourism consumption in people's daily consumption gradually increased. In the context of the continuous development of Interact technology, consumer network characteristics become more and more obvious, followed by the emergence of a new consumer groups, that is, travel network consumers. Tourism network consumers as a new consumer group develop rapidly. The rapid development of the Internet has led to the great changes in the tourism industry. However, because of the tourism developers' only immediate interests, wanton development of tourism base, and the weak public awareness of tourism, the environment caused serious damage. This paper elaborates the concrete manifestation of the sustainable development of tourism, analyzes the adverse effects of the tourism industry on the ecological environment in sustainable development, and puts forward effective measures to promote the coordinated development of tourism and environmental protection.展开更多
The erythroid- and developmental stage-specific expression of the human ε-globin gene is controlled, in part,by the 5’-flanking DNA sequence of this gene. In the present study, we have used DNA-protein binding assay...The erythroid- and developmental stage-specific expression of the human ε-globin gene is controlled, in part,by the 5’-flanking DNA sequence of this gene. In the present study, we have used DNA-protein binding assays to identify trans-acting factors which regulate the temporal expression of the human ε-globin gene during development. Using gel mobility shift assays and DNasel footprinting assays, a nuclear protein factor (termed ε-SSF1) in the nuclear extracts from mouse haematopoietic tissues at d 11 and d 13 of gestation was identified. It could specifically bind to the positive control region (between -535 and -453bp) of the human ε-globin gene. We speculated that the E-SSF1 might be an erythroid- and developmental stage-specific activator. In addition, we found another nuclear protein factor (termed ε-R1) in the nuclear extract from mouse fetal liver at d 18 of gestation, which could strongly bind to the silencer region (between -392 and -177bp) of this gene. Therefore, we speculated that the ε-R1 might be an erythroid- and developmental stagespecific repressor. Our data suggest that both ε-SSF1 and ε-R1 might play important roles in developmental regulation of the human ε-globin gene expression during the early embryonic life. On the other hand, we observed that the binding patterns of nuclear proteins from three cell lines (K562, HEL and Raji) to these regulatory regions were partially different. These results suggest that different trans-acting factors in K562, HEL and Raji cells might be responsible for activating or silencing the human ε-globin gene in three different cell lines.展开更多
In this study, the seasonal transition of precipitation over the middle and lower reaches of the Yang-tze River Valley (YRV) from late spring to early summer is investigated. The results show that the seasonal transit...In this study, the seasonal transition of precipitation over the middle and lower reaches of the Yang-tze River Valley (YRV) from late spring to early summer is investigated. The results show that the seasonal transition of precipitation exhibits multi-modes. One of these modes is characterized by an abrupt transition from drought to flood (ATDF) over the middle and lower reaches of the YRV in the seasonal transition of precipitation. It is shown that the ATDF event from May to June 2011 is simply one prominent case of the ATDF mode. The ATDF mode exhibits an obvious decadal variability. The mode has occurred more frequently since 1979, and its amplitude has apparently strengthened since 1994. From the climatic view, the ATDF mode configures a typical seasonal circulation transition from winter to summer, for which the winter circulations are prolonged, and the summer circulations with the rainy season are built up early over the YRV.展开更多
September 7,2014Thousands of lanterns take to the skies in Yichun City of Jiangxi Province during a local Moon Culture Tourism Festival.September 1,2014Students at a primary school in Taizhou,southeast China’s Zhejia...September 7,2014Thousands of lanterns take to the skies in Yichun City of Jiangxi Province during a local Moon Culture Tourism Festival.September 1,2014Students at a primary school in Taizhou,southeast China’s Zhejiang Province sprint around the country’s first rooftop running track.展开更多
With the rapid development of economy and increase of population in the drainage areas, the nutrient loading has increased dramatically in the Changjiang estuary and adjacent coastal waters. To properly assess the imp...With the rapid development of economy and increase of population in the drainage areas, the nutrient loading has increased dramatically in the Changjiang estuary and adjacent coastal waters. To properly assess the impact of nutrient enrichment on phytoplankton community, seasonal microcosm experiments were conducted during August 2010-July 2011 in the coastal waters of Zhejiang Province. The results of the present study indicated that the chl a concentration, cell abundance, diversity indices, species composition and community succession of the phytoplankton varied significantly with different N/P ratios and seasons. Higher growth was observed in the 64:1 (spring), 32:1 (summer), 16:1 (autumn) and 128:1,256:1 (winter) treatments, respectively. The values of Shannon-Wiener index (H) and Pielou evenness index (J) were lower in the 8:1 and 16:1 treatments in autumn test, while H value was higher in the 128:1 and 8:1 treatments in winter test. A definite community succession order from diatoms to dinoflagel lares was observed in the autumn and winter tests, while the diatoms dominated the community throughout the culture in the spring and summer tests.展开更多
This article aims to describe the perception of the residents of Tepoztlan Morelos regarding the level of employment since their designation as Magic Town. Tepoztlan is a municipality in the northern part of the State...This article aims to describe the perception of the residents of Tepoztlan Morelos regarding the level of employment since their designation as Magic Town. Tepoztlan is a municipality in the northern part of the State of Morelos, located in the South-Central of Mexico. It is a magical town situated on the slopes of the Tepozteco Mountain. It is recognized as one of the most attractive places in the aforementioned state. Its relative proximity to Mexico City makes this town an attractive tourist destination for visitors. The importance of this issue lies mainly in the fact that tourism is one of the largest sources of income and employment generation for the country, so it is essential to strengthen the tourism infrastructure through federal programs of social participation, which promotes the development from the bottom to top. With that objective, the Mexican government created a federal program primarily with the purpose of contributing to the development of rural tourism. So, the "Magic Towns" program emerged as a strategy to generate resources for certain communities and increase the tourist offer. Tepoztlan was one of the first towns to enter the program, so it is relevant to analyze if the benefits generated by this program related to employment are perceived by the population. That is to say, to know the opinion of the settlers on the increase and the conditions of the employment that tourism generates and how the denomination of magical town influences this. Regarding the method used, we can say that it is a research with a quantitative approach, a questionnaire was designed as an instrument for data collection. The sample was obtained by the sampling method called: simple random probabilistic sampling. The results presented here correspond to a sample of 119 inhabitants of Tepoztlan. In summary, the research on this subject allows us to conclude that there is an increase in the generation of jobs in Tepoztl/m since its denomination as Magical Town; however, the working conditions and remuneration generated by tourism are perceived as low and far from the expectations of the population.展开更多
This study aims to investigate the seasonal variations in copepod community structure and prosome length of dominant species from March 2009 to January 2010 around artificial reefs in Xiaoshi Island, Yellow Sea, Weiha...This study aims to investigate the seasonal variations in copepod community structure and prosome length of dominant species from March 2009 to January 2010 around artificial reefs in Xiaoshi Island, Yellow Sea, Weihai, China. Samples were collected using two types of plankton net (Model I and Model II) for different-sized copepods. The number of taxon was calculated from the data of both the net types, while the copepod abundance was done using the samples from Model II only. Sixteen species of planktonic copepods, including 5 dominant species, were recorded. Results reveal that Oithona similis was the first dominant species from March to June, and was replaced by Paracalanus parvus in September; both dominated the copepod community in January. Acartia hongi was the second dominant species from March to September. Centropages abdominalis was the third dominant species from March to June, and was replaced by O. sirnilis in September and Corycaeus aJfinis in January. C. affinis was the fourth dominant species in September. Population density of the dominant copepods was compared with that of other similar regions. We found that the dominant species were mostly small copepods (〈1 mm) except for adult Centrapages abdominalis. Seasonal variation in prosome length of O. similis, C. abdominalis, and C. affinis, and their copepodites were studied for the first time in China. For P. parvus and A. hongi, seasonal trends in prosome length variation were similar with those in Jiaozhou Bay, Yellow Sea, Qingdao, China, in a similar temperate domain. The results are helpful for future calculation of copepod biomass and production, and for investigation of the relationship between copepods and fish resources.展开更多
The characteristics of seasonal variation in phytoplankton biomass and dominant species in the Changjiang River Estuary and adjacent seas were discussed based on field investigation data from 1959 to 2009. The field d...The characteristics of seasonal variation in phytoplankton biomass and dominant species in the Changjiang River Estuary and adjacent seas were discussed based on field investigation data from 1959 to 2009. The field data from 1981 to 2004 showed that the Chlorophyll-a concentration in surface seawater was between 0.4 and 8.5 ktg dm-3. The seasonal changes generally presented a bimodal trend, with the biomass peaks occurring in May and August, and Chlorophyll-a concentration was the lowest in winter. Seasonal biomass changes were mainly controlled by temperature and nutrient levels. From the end of autumn to the next early spring, phytoplankton biomass was mainly influenced by temperature, and in other seasons, nutrient level (including the nutrient supply from the terrestrial runoffs) was the major influence factor. Field investigation data from 1959 to 2009 demonstrated that dia- toms were the main phytoplankton in this area, and Skeletonerna costatum, Pseudo-nitzschia pungens, Coscinodiscus oculus-iridis, Thalassinoema nitzschioides, Paralia sulcata, Chaetoceros lorenzianus, Chaetoceros curvisetus, and Prorocentrum donghaiense Lu were common dominant species. The seasonal variations in major dominant phytoplankton species presented the following trends: 1) Skeletonema (mainly S. costatum) was dominant throughout the year; and 2) seasonal succession trends were Coscinodiscus (spring) →Chaetoceros (summer and autumn) → Coscinodiscus (winter). The annual dominance of S. costatum was attributed to its environmental eurytopicity and long standing time in surface waters. The seasonal succession of Coscinodiscus and Chaetoceros was associated with the seasonal variation in water stability and nutrient level in this area. On the other hand, long-term field data also indicated obvious interannual variation of phytoplankton biomass and community structure in the Changjiang River Estuary and adjacent seas: average annual phytoplankton biomass and dinoflagellate proportion both presented increased trends during the 1950s - 2000s.展开更多
The seasonal variations in phytoplankton community structure were investigated for the Sanggou Bay (SGB) and the adjacent Ailian Bay (ALB) and Lidao Bay (LDB) in Shandong Peninsula,eastern China.The species comp...The seasonal variations in phytoplankton community structure were investigated for the Sanggou Bay (SGB) and the adjacent Ailian Bay (ALB) and Lidao Bay (LDB) in Shandong Peninsula,eastern China.The species composition and cell abundance of phytoplankton in the bay waters in spring (April 2011),summer (August 2011),autumn (October 2011),and winter (January 2012) were examined using the Uterm6hl method.A total of 80 taxa of phytoplankton that belong to 39 genera of 3 phyla were identified.These included 64 species of 30 genera in the Phylum Bacillariophyta,13 species of 8 genera in the Phylum Dinophyta,and 3 species of 1 genus in the Phylum Chrysophyta.During the four seasons,the number of phytoplankton species (43) was the highest in spring,followed by summer and autumn (40),and the lowest number ofphytoplankton species (35) was found in winter.Diatoms,especially Paralia sulcata (Ehrenberg) Cleve and Coscinodiscus oculus-iridis Ehrenberg,were predominant in the phytoplankton community throughout the study period,whereas the dominance of dinoflagellate appeared in summer only.The maximum cell abundance of phytoplankton was detected in summer (average 8.08 × 103 cells L-1) whereas their minimum abundance was found in autumn (average 2.60 x 103 cellsL-1).The phytoplankton abundance was generally higher in the outer bay than in the inner bay in spring and autumn.In summer,the phytoplankton cells were mainly concentrated in the south of inner SGB,with peak abundance observed along the western coast.In winter,the distribution of phytoplankton cells showed 3 patches,with peak abundance along the western coast as well.On seasonal average,the Shannon-Wiener diversity indices of phytoplankton community ranged from 1.17 to 1.78 (autumn 〉 summer 〉 spring 〉 winter),and the Pielou's evenness indices of phytoplankton ranged from 0.45 to 0.65 (autumn 〉 spring 〉 summer〉 winter).According to the results of canonical correspondence analysis,phosphate level was the major factor that limited the occurrence of P.sulcata and C.oculus-iridis,whereas optimal temperature and low salinity were responsible for Prorocentrum blooms in summer.The detailed description of seasonal variations in phytoplankton community structure in the three bays provide reference data for future studies on marine ecosystems and mariculture in adjacent areas.展开更多
基金Under the auspices of Major State Basic Research Development Program of China(No.2006CB403201)
文摘Traditionally,patch-based analysis at the landscape scale fragmentation has been used in the study of landscape ecology while the study of boundary and node has not been considered as much detail until recently.This study investigated the possibility of applying boundary-and node-based methods in landscape pattern analysis to the upper reaches of the Minjiang River in the southwestern China.Boundary-based and node-based landscape indices were selected to be used in analyzing changes in landscape patterns,and the results were compared with analysis using traditional pattern indices.We compared the responses of patch-area-based,boundary-length-based and node-number-based indices,and concluded that boundary-based and node-based indices are more sensitive to disturbance than patch-based indices with various patterns,and node-based indices are even more sensitive than boundary-based ones.Thus,the results suggest that boundary-based and node-based pattern analysis methods provide helpful supplementary information to traditional patch-based pattern analysis methods.The results about pattern dynamics of landscapes in the upper reaches of the Minjiang River based on boundaries and nodes showed that with human disturbance,the dominance of forest landscape was weakened by other landscape types;thus the landscape pattern of the study area became more homogeneous and the boundary network became more complex.These changes further augmented disturbance interfaces in the landscape and increased the possibilities of further landscape fragmentation.
基金Supported by the National Major Programs of Water Body Pollution Control and Remediation(No.2012ZX07103003-02)the National Basic Research Program of China(973 Program)(No.2008CB418000)
文摘To understand the responses of a freshwater ecosystem to the impoundment of the Three Gorges Reservoir (TGR), phytoplankton was monitored in the tributaries of the TGR area. From August 2010 to July 2011, algal species composition, abundance, chlorophyll a and other environmental parameters were investigated in the Gaolan River, which is a tributary of Xiangxi River. Thirty-one algal genera from seven phyla were identified. Results show that the lowest concentrations of total phosphorus (TP) and total nitrogen (TN) were 0.06 mg/L and 1.08 rag/L, respectively. The values of TP and TN exceeded the threshold concentration of the eutrophic state suggested for freshwater bodies. In the Gaolan River, the succession of phytoplankton showed clear seasonal characteristics. Different dominant species were observed among seasons under the control of environment factors. In spring and summer, the dominant species were Nitzschia sp. and Aphanizomenon flos-aquae (L.) Ralfs, the limiting nutrient was NO3^--N, and the key environmental factor for phytoplankton population succession was water temperature (WT). In autumn and winter, the dominant species were A.flos-aquae and Chlorella sp., the limiting nutrient was pO3--P, and the key environmental factors were transparency and WT. This study illustrates the influence of physical and chemical factors on phytoplankton seasonal succession in a tributary of TGR since the downstream regions of Xiangxi River and Gaolan River became reservoirs after impoundment of the Three Gorges Dam. We suggest that this activity has significantly affected water quality in the dam area.
文摘Paracalanus parvus, Paracalanus crassirostris , and Acartia bifilosa are dominant and widely distributed in the Bohai Sea, and comprise an important part of zooplankton in terms of biomass as well as production rate. In order to understand their seasonal distribution and population dynamics, their stage specific abundance in different months of the year were analyzed based on the never analyzed yet samples collected in 1959. The three species showed clear and remarkable seasonal variation in abundance, which maximized in spring and summer, when they formed high biomass patches or concentrations in the nearshore area. For Paracalanus parvus , two peaks were observed in the annual circle, one in June and the other in September. For Paracalanus crassirostris , one peak occurred in summer and a small one in December. The seasonal pattern of Acartia bifilosa was different in different regions. In Bohai Bay it had a two peak pattern, with the first large peak occurring in May and the second one in October. In Laizhou Bay, a winter peak in December and January could be observed besides the spring one. The number of generations during the reproductive season for the three species was estimated based on the annual cycle in abundance and ambient temperature.
基金Supported by the National Key Technology R&D Program of China(No.2007BAD43B01)the National Special Research Fund for Non-Profit Sector(Agriculture)(No.201303047)the Special Fund of Chinese Central Government for Basic Scientific Research Operations in Commonweal Research Institutes(No.2008T04)
文摘The diversity,community structure and seasonal variation in demersal nekton off the Changjiang(Yangtze)River estuary was evaluated using monthly trawl survey data,collected between December 2008 and November 2009.A total of 95 species(56 teleosts,11 cephalopods,and 28 decapod crustaceans)from 69 genera,49 families and 15 orders were collected.These species could be classifi ed into six groups on the basis of temporal distribution patterns.The resident crab Ovalipes punctatus dominated the community,both in number and biomass.A clear seasonal succession was observed in the species composition.Cluster analysis revealed three primary seasonal groups corresponding to the samples collected in winter-spring,late spring-summer and late summer-autumn.The highest biomass and lowest diversity were observed in summer,while the lowest biomass and highest diversity in winter.The abundance-biomass comparison curves and community composition suggested that the investigated community was moderately disturbed.The results suggest that reduction in fi shing pressure and in the degree of seasonal hypoxia are essential for sustainable resource management off the Changjiang River estuary.
基金supported by the China National Natural Science Foundation (Grant Nos. 41201580, 40121553, 41201586)the research project on heritage tourism from China National Tourism Administration to Dr. Sun Ye-hong (Grant No. 13TAAG014)+2 种基金project of Construction of Innovative Teams and Teacher Career Development for Universities and Colleges under Beijing Municipality (Grant No. IDHT20130513)the international project of "GEF-FAO/GIAHS dynamic conservation and adaptive management", a research program at the Institute of Geographic SciencesNatural Resources Research of the Chinese Academy of Sciences
文摘Community plays an important role in the preservation of agricultural heritage system (AHS). Recently, many AHS have been valorized as interesting resources for rural tourism. The expectations are that tourism development (TD) can be supportive for the conservation of AHS while creating benefits for local communities. In this study, two mountainous pilot villages (Longxian and Xiaohuang) in a global conservation project for traditional agricutural systems - Globally Important Agricultural Heritage Systems (GIAHS) were selected to identify the relationship between AHS conservation and TD. The study undertook in-depth interviews, and questionnaires of village residents and informal discussions with local villagers. A t-test and a linear regression model were implemented to explore the comparative dimensions of the two communities with different geographical location, economic situation, and stage of TD. The research found some similarities and differences in the two mountainous communities during AHS conservation and TD. Firstly, AHS are preservaed well in both villages unconsiously, while the residents in Xiaohuang value more highly the heritage elements than the respondents in Longxian, and the villagers in Xiaohuang are more worried about their heritage system; Secondly, both villages expect lots of benefits from TD and they clearly perceive more positive than negative impact from tourism and thus approve TD, while the hugedifferent perception on transportation and accessibility in the two villages reflects the bottleneck of TD in Xiaohuang village. At the same time, the respondents from Xiaohuang perceive more positive and fewer negative impact from tourism than the respondents from Longxian. Thirdly, the respondents in the two villages all show positive attitudes towards participation in tourism mostly motivated by the high income expectation. The main factors to determine the community perception in two villages were also analyzed based on the data process. A location-based coneeputal framework of AHS conservation in partnership with TD at community scale is proposed at the end of the paper. The dynamics of tourism development, that could enhance a better understanding of the complex relationship between conservation objectives and tourism development are discussed.
基金the National High.Technology Research and Development Programme of China(2004AA404013)
文摘Pressure activity data as an important index of gastrointestinal (GI) motility can be obtained from the wireless radiotelemetry capsule. The Hilbert-Huang transform (HHT) method, which is more effective to process non-stationary signal, is proposed to identify the characteristics of GI motility. We decompose the pressure activity data into intrinsic mode functions (IMFs), calculate the Hi/bert marginal spectrum and attain the peristalsis characteristics of GI tract. The IMFs represent the peristalses modes of GI tract activity embedded in the pressure data. The time-varying characteristic of the method suggests that the HHT is suitable to accommodate other non-stationary biomedical data analysis.
基金This work was supported by the National Natural Science Foundation of China[grant number 41420104002]the Natural Science Foundation of Jiangsu Province[grant numbers BK20150907 and 14KJA170002].
文摘This work investigates the boreal-summer intraseasonal variability(ISV)of the precipitation over the lower reaches of the Yangtze River basin(LYRB)during 1979–2016,based on daily Climate Prediction Center global precipitation data.The ISV of the summer monsoon rainfall over the LYRB is mainly dominated by the lower-frequency 12–20-day variability and the higher-frequency 8–12-day variability.The lower-frequency variability is found to be related to the northwestwardpropagating quasi-biweekly oscillation(QBWO)over the western North Pacific spanning the South China Sea(SCS)and Philippine Sea,while the higher-frequency variability is related to the southeastward propagating midlatitude wave train(MLWT).Moreover,not each active QBWO(MLWT)in the SCS(East Asia)can generate ISV components of the precipitation anomaly over the LYRB.The QBWO can change the rainfall significantly with the modulation of mean state precipitation,while the quasi-11-day mode mainly depends on the intensity of the MLWT rather than the mean precipitation change.These findings should enrich our understanding of the ISV of the East Asian summer monsoon and improve its predictability.
基金supported by the Climate Change Science Foundation of China Meteorological Administration(No.CCSF2011-1)
文摘The annual and seasonal trends in pan evaporation in the lower Yellow River Basin based on quality-controlled data from 10 meteorological stations in 1961-2010 are analyzed. The causes for the changes in annual and seasonal pan evaporation are also discussed. The results suggest that, despite the 1.15~C increasing in annual mean surface air temperature over the past 50 years (0.23°C per decade), the annual pan evaporation has steadily declined by an average rate of-7.65 mm per year. By comparison, this change is greater than those previously reported in China. Significant decreasing trends in annual pan evaporation have been observed at almost all stations. As a whole, seasonal pan evaporation decreased significantly, especially in summer, whereas seasonal temperature increased significantly, except in summer. Thus, the pan evaporation paradox exists in the lower Yellow River Basin. The trend analysis of other meteorological factors indicates significant decrease in sunshine duration and wind speed, but no significant variations in precipitation and relative humidity at annual and seasonal time scales. By examining the relationship between precipitation and pan evaporation, it did not show a concurrent decrease in pan evaporation and increase in precipitation. The partial correlation analysis discovered that the primary cause of decrease in annual and seasonal pan evaporation is the decrease in wind speed. A further examination using a stepwise regression shows that decrease in wind speed and sunshine duration, and increase in mean temperature axe likely to be the main meteorological factors affecting the annual and seasonal pan evaporation in the lower Yellow River Basin over the past 50 years.
文摘With the rapid development of China's tourism market and the gradual improvement of people's pace of life, tourism has become an important way to relax people, so the proportion of tourism consumption in people's daily consumption gradually increased. In the context of the continuous development of Interact technology, consumer network characteristics become more and more obvious, followed by the emergence of a new consumer groups, that is, travel network consumers. Tourism network consumers as a new consumer group develop rapidly. The rapid development of the Internet has led to the great changes in the tourism industry. However, because of the tourism developers' only immediate interests, wanton development of tourism base, and the weak public awareness of tourism, the environment caused serious damage. This paper elaborates the concrete manifestation of the sustainable development of tourism, analyzes the adverse effects of the tourism industry on the ecological environment in sustainable development, and puts forward effective measures to promote the coordinated development of tourism and environmental protection.
文摘The erythroid- and developmental stage-specific expression of the human ε-globin gene is controlled, in part,by the 5’-flanking DNA sequence of this gene. In the present study, we have used DNA-protein binding assays to identify trans-acting factors which regulate the temporal expression of the human ε-globin gene during development. Using gel mobility shift assays and DNasel footprinting assays, a nuclear protein factor (termed ε-SSF1) in the nuclear extracts from mouse haematopoietic tissues at d 11 and d 13 of gestation was identified. It could specifically bind to the positive control region (between -535 and -453bp) of the human ε-globin gene. We speculated that the E-SSF1 might be an erythroid- and developmental stage-specific activator. In addition, we found another nuclear protein factor (termed ε-R1) in the nuclear extract from mouse fetal liver at d 18 of gestation, which could strongly bind to the silencer region (between -392 and -177bp) of this gene. Therefore, we speculated that the ε-R1 might be an erythroid- and developmental stagespecific repressor. Our data suggest that both ε-SSF1 and ε-R1 might play important roles in developmental regulation of the human ε-globin gene expression during the early embryonic life. On the other hand, we observed that the binding patterns of nuclear proteins from three cell lines (K562, HEL and Raji) to these regulatory regions were partially different. These results suggest that different trans-acting factors in K562, HEL and Raji cells might be responsible for activating or silencing the human ε-globin gene in three different cell lines.
基金supported by the National Basic Research Program of China (Grant No.2009CB421401)the National Key Technologies R&D Program of China (Grant No. 2009BAC51B02)+1 种基金the National Natural Science Foundation of China (Grant No. 40975022)the Special Scien-tific Research Fund of the Meteorological Public Welfare Profession of China (Grant No. GYHY200906018)
文摘In this study, the seasonal transition of precipitation over the middle and lower reaches of the Yang-tze River Valley (YRV) from late spring to early summer is investigated. The results show that the seasonal transition of precipitation exhibits multi-modes. One of these modes is characterized by an abrupt transition from drought to flood (ATDF) over the middle and lower reaches of the YRV in the seasonal transition of precipitation. It is shown that the ATDF event from May to June 2011 is simply one prominent case of the ATDF mode. The ATDF mode exhibits an obvious decadal variability. The mode has occurred more frequently since 1979, and its amplitude has apparently strengthened since 1994. From the climatic view, the ATDF mode configures a typical seasonal circulation transition from winter to summer, for which the winter circulations are prolonged, and the summer circulations with the rainy season are built up early over the YRV.
文摘September 7,2014Thousands of lanterns take to the skies in Yichun City of Jiangxi Province during a local Moon Culture Tourism Festival.September 1,2014Students at a primary school in Taizhou,southeast China’s Zhejiang Province sprint around the country’s first rooftop running track.
基金supported by the Ministry of Science and Technology of P.R.China under grant contracts (No.2010CB428903)the National Natural Science Foundation of China (No.41306112)+3 种基金the National Marine Public Welfare Research Project of China (Nos.201305043,200805069)the Zhejiang Provincial Natural Science Foundation (Nos.LY13D060004,Y5110131)the Marine Science Foundation of State Oceanic Administration for Youth (Nos.2013140,2013144)the Basic Scientific Research Fund of SIO,China (Nos.JG1311,JG1221)
文摘With the rapid development of economy and increase of population in the drainage areas, the nutrient loading has increased dramatically in the Changjiang estuary and adjacent coastal waters. To properly assess the impact of nutrient enrichment on phytoplankton community, seasonal microcosm experiments were conducted during August 2010-July 2011 in the coastal waters of Zhejiang Province. The results of the present study indicated that the chl a concentration, cell abundance, diversity indices, species composition and community succession of the phytoplankton varied significantly with different N/P ratios and seasons. Higher growth was observed in the 64:1 (spring), 32:1 (summer), 16:1 (autumn) and 128:1,256:1 (winter) treatments, respectively. The values of Shannon-Wiener index (H) and Pielou evenness index (J) were lower in the 8:1 and 16:1 treatments in autumn test, while H value was higher in the 128:1 and 8:1 treatments in winter test. A definite community succession order from diatoms to dinoflagel lares was observed in the autumn and winter tests, while the diatoms dominated the community throughout the culture in the spring and summer tests.
文摘This article aims to describe the perception of the residents of Tepoztlan Morelos regarding the level of employment since their designation as Magic Town. Tepoztlan is a municipality in the northern part of the State of Morelos, located in the South-Central of Mexico. It is a magical town situated on the slopes of the Tepozteco Mountain. It is recognized as one of the most attractive places in the aforementioned state. Its relative proximity to Mexico City makes this town an attractive tourist destination for visitors. The importance of this issue lies mainly in the fact that tourism is one of the largest sources of income and employment generation for the country, so it is essential to strengthen the tourism infrastructure through federal programs of social participation, which promotes the development from the bottom to top. With that objective, the Mexican government created a federal program primarily with the purpose of contributing to the development of rural tourism. So, the "Magic Towns" program emerged as a strategy to generate resources for certain communities and increase the tourist offer. Tepoztlan was one of the first towns to enter the program, so it is relevant to analyze if the benefits generated by this program related to employment are perceived by the population. That is to say, to know the opinion of the settlers on the increase and the conditions of the employment that tourism generates and how the denomination of magical town influences this. Regarding the method used, we can say that it is a research with a quantitative approach, a questionnaire was designed as an instrument for data collection. The sample was obtained by the sampling method called: simple random probabilistic sampling. The results presented here correspond to a sample of 119 inhabitants of Tepoztlan. In summary, the research on this subject allows us to conclude that there is an increase in the generation of jobs in Tepoztl/m since its denomination as Magical Town; however, the working conditions and remuneration generated by tourism are perceived as low and far from the expectations of the population.
基金Supported by the National Natural Science Foundation of China(No.41106133)the Shandong University Independent Innovation Foundation(No.2011ZRYQ005)the Program of Academy of Marine Research in Weihai(No.000041342080)
文摘This study aims to investigate the seasonal variations in copepod community structure and prosome length of dominant species from March 2009 to January 2010 around artificial reefs in Xiaoshi Island, Yellow Sea, Weihai, China. Samples were collected using two types of plankton net (Model I and Model II) for different-sized copepods. The number of taxon was calculated from the data of both the net types, while the copepod abundance was done using the samples from Model II only. Sixteen species of planktonic copepods, including 5 dominant species, were recorded. Results reveal that Oithona similis was the first dominant species from March to June, and was replaced by Paracalanus parvus in September; both dominated the copepod community in January. Acartia hongi was the second dominant species from March to September. Centropages abdominalis was the third dominant species from March to June, and was replaced by O. sirnilis in September and Corycaeus aJfinis in January. C. affinis was the fourth dominant species in September. Population density of the dominant copepods was compared with that of other similar regions. We found that the dominant species were mostly small copepods (〈1 mm) except for adult Centrapages abdominalis. Seasonal variation in prosome length of O. similis, C. abdominalis, and C. affinis, and their copepodites were studied for the first time in China. For P. parvus and A. hongi, seasonal trends in prosome length variation were similar with those in Jiaozhou Bay, Yellow Sea, Qingdao, China, in a similar temperate domain. The results are helpful for future calculation of copepod biomass and production, and for investigation of the relationship between copepods and fish resources.
基金the National Basic Research Program of China (Nos. 2001 CB409703 and 2010CB428701)the National Natural Science Foundation of China (Nos. 41140037 and 41276 069)
文摘The characteristics of seasonal variation in phytoplankton biomass and dominant species in the Changjiang River Estuary and adjacent seas were discussed based on field investigation data from 1959 to 2009. The field data from 1981 to 2004 showed that the Chlorophyll-a concentration in surface seawater was between 0.4 and 8.5 ktg dm-3. The seasonal changes generally presented a bimodal trend, with the biomass peaks occurring in May and August, and Chlorophyll-a concentration was the lowest in winter. Seasonal biomass changes were mainly controlled by temperature and nutrient levels. From the end of autumn to the next early spring, phytoplankton biomass was mainly influenced by temperature, and in other seasons, nutrient level (including the nutrient supply from the terrestrial runoffs) was the major influence factor. Field investigation data from 1959 to 2009 demonstrated that dia- toms were the main phytoplankton in this area, and Skeletonerna costatum, Pseudo-nitzschia pungens, Coscinodiscus oculus-iridis, Thalassinoema nitzschioides, Paralia sulcata, Chaetoceros lorenzianus, Chaetoceros curvisetus, and Prorocentrum donghaiense Lu were common dominant species. The seasonal variations in major dominant phytoplankton species presented the following trends: 1) Skeletonema (mainly S. costatum) was dominant throughout the year; and 2) seasonal succession trends were Coscinodiscus (spring) →Chaetoceros (summer and autumn) → Coscinodiscus (winter). The annual dominance of S. costatum was attributed to its environmental eurytopicity and long standing time in surface waters. The seasonal succession of Coscinodiscus and Chaetoceros was associated with the seasonal variation in water stability and nutrient level in this area. On the other hand, long-term field data also indicated obvious interannual variation of phytoplankton biomass and community structure in the Changjiang River Estuary and adjacent seas: average annual phytoplankton biomass and dinoflagellate proportion both presented increased trends during the 1950s - 2000s.
基金supported by the National Program on Key Basic Research Project of China (Grant Nos. 2011CB409804 and 2015CB954002)Program for New Century Excellent Talents in University (NCET-12-1065)the National Natural Science Foundation of China (Grant No.41176136) to J. Sun
文摘The seasonal variations in phytoplankton community structure were investigated for the Sanggou Bay (SGB) and the adjacent Ailian Bay (ALB) and Lidao Bay (LDB) in Shandong Peninsula,eastern China.The species composition and cell abundance of phytoplankton in the bay waters in spring (April 2011),summer (August 2011),autumn (October 2011),and winter (January 2012) were examined using the Uterm6hl method.A total of 80 taxa of phytoplankton that belong to 39 genera of 3 phyla were identified.These included 64 species of 30 genera in the Phylum Bacillariophyta,13 species of 8 genera in the Phylum Dinophyta,and 3 species of 1 genus in the Phylum Chrysophyta.During the four seasons,the number of phytoplankton species (43) was the highest in spring,followed by summer and autumn (40),and the lowest number ofphytoplankton species (35) was found in winter.Diatoms,especially Paralia sulcata (Ehrenberg) Cleve and Coscinodiscus oculus-iridis Ehrenberg,were predominant in the phytoplankton community throughout the study period,whereas the dominance of dinoflagellate appeared in summer only.The maximum cell abundance of phytoplankton was detected in summer (average 8.08 × 103 cells L-1) whereas their minimum abundance was found in autumn (average 2.60 x 103 cellsL-1).The phytoplankton abundance was generally higher in the outer bay than in the inner bay in spring and autumn.In summer,the phytoplankton cells were mainly concentrated in the south of inner SGB,with peak abundance observed along the western coast.In winter,the distribution of phytoplankton cells showed 3 patches,with peak abundance along the western coast as well.On seasonal average,the Shannon-Wiener diversity indices of phytoplankton community ranged from 1.17 to 1.78 (autumn 〉 summer 〉 spring 〉 winter),and the Pielou's evenness indices of phytoplankton ranged from 0.45 to 0.65 (autumn 〉 spring 〉 summer〉 winter).According to the results of canonical correspondence analysis,phosphate level was the major factor that limited the occurrence of P.sulcata and C.oculus-iridis,whereas optimal temperature and low salinity were responsible for Prorocentrum blooms in summer.The detailed description of seasonal variations in phytoplankton community structure in the three bays provide reference data for future studies on marine ecosystems and mariculture in adjacent areas.