[Objective] The aim was to observe the antibacterial effect of nano-scale Titanium dioxide on parasitic bacterium of Nanfeng Citrus in storage period.[Method] Nano-scale Titanium dioxide was prepared by dibutyl phthal...[Objective] The aim was to observe the antibacterial effect of nano-scale Titanium dioxide on parasitic bacterium of Nanfeng Citrus in storage period.[Method] Nano-scale Titanium dioxide was prepared by dibutyl phthalate through sol-gel method under anhydrous conditions,and orthogonal experiment was used to determine optimum conditions for nano-scale Titanium dioxide preparation,and structure characterization of nano-scale Titanium dioxide was carried out by X-Ray diffractometer.Oxford cup method was used to explore inhibition effect of nano-scale Titanium dioxide suspension on the activity of normal parasitic bacterium of Nanfeng Citrus.Simultaneously,the empirical preservation test was carried out.[Result] The average diameter of nano-scale Titanium dioxide powder attained to 14.6 nm,actual average yield could reach 90.83% with RSD（Relative Standard Deviation）of 0.86%.[Conclusion] Nano-scale Titanium dioxide had good antibacterial effect on the parasitic bacterium of Nanfeng Citrus in storage period.展开更多
[Objective] The aim was to study on biological characteristics of photosynthetic response for young trees of B. macrostachya in seasonal rain forest, providing scientific reference for protection of tropical rain fore...[Objective] The aim was to study on biological characteristics of photosynthetic response for young trees of B. macrostachya in seasonal rain forest, providing scientific reference for protection of tropical rain forest under change of global climate. [Method] Young trees of B. macrostachya in Xishuangbanna tropical forest were chosen to research in foggy season, dry and hot season, and rainy season to measure dynamics of season changes. [Result] For young trees of B. macrostachya in Yunnan Province, Pn max was the biggest in rainy season, followed by dry and hot season and foggy season at 4.08, 2.89 and 1.81 μmol/（m·s） respectively; Gs and Tr in rainy season were the highest and WUE in dry season was the highest; Gi achieved peak in foggy season, of which the highest values were 0.18 and 1.59 mmol/（m 2 ·s）, and 7.35 μmol/mmol and 455 mmol/（m 2 ·s）; Ci showed an opposite trend with that of WUE, and Gs and Tr changed similarly. [Conclusion] Young trees of B. macrostachya in seasonal rain forest are of significant seasonal change in photosynthetic response, and young trees are shade tolerant.展开更多
According to the Energy Information Administration, average retail gasoline prices tend to typically be higher in certain states than in others. Aside from taxes, the factors shown to contribute to regional and even l...According to the Energy Information Administration, average retail gasoline prices tend to typically be higher in certain states than in others. Aside from taxes, the factors shown to contribute to regional and even local differences in gasoline prices include proximity of supply, supply disruptions, competition in the local market and environmental programs. Of interest in this paper is proximity of supply. It has been hypothesized that areas farthest from the Gulf Coast （the source of nearly half of the gasoline produced in the United States and, thus, a major supplier to the rest of the country） tend to have higher prices. To test this hypothesis, the paper assembles state level monthly retail gasoline data for the period 1983 to 2007 for five states with oil refineries （Alabama, Georgia, Texas, Mississippi and Louisiana） and five states without refineries （Arkansas, Tennessee, North Carolina, South Carolina and Florida）. The analysis employs dynamic correlation, regression, cointegration and vector autoregressive methods. Overall, the results show that retail gas prices in states with refineries and those without refineries tend to move in the same direction over time. The small differences observed over time may suggest that price shocks take a short time to be felt nationwide.展开更多
The issues and challenges of minimum adequate public school education in the State of South of South Carolina has been a struggle between lawmakers and taxpayers for more than fifty years. The enactment of the Civil R...The issues and challenges of minimum adequate public school education in the State of South of South Carolina has been a struggle between lawmakers and taxpayers for more than fifty years. The enactment of the Civil Rights Act of 1964 led to forced school integration, busing, and led to whites＇ physical moving out of selected school districts. Selected public schools filed a lawsuit against the State of South Carolina to the Supreme Court with the claim of failing to provide adequate and equal education to all children in the state. This reflection focuses on the Abbeville case in context, funding issues, and inadequate facilities, which concludes with a reflective view of the Brown v. The Board of Edueation 1954 decision.展开更多
1 INTRODUCTION As one of the main factors affecting input and use of precipitation by forests, rainfall also makes a difference on partitioning of gross precipitation over the canopy, equilibrium of water amount in ri...1 INTRODUCTION As one of the main factors affecting input and use of precipitation by forests, rainfall also makes a difference on partitioning of gross precipitation over the canopy, equilibrium of water amount in river basins and water cycling processes . In view of its poorlydefined four seasons in contrast to well-defined dry and wet spells in addition to its inland location, understanding of precipitation characteristics and tendencies is important for the study on local forestry hydrology. Relevant research has been documented, but few have dealt with multiple time scales at the hourly, daily, monthly and annual intervals. With the 1992 - 2003 automatic record of precipitation in Menglun, Xishuangbannan analyzed, its characteristics and trends are summarized to help in the study on forestry hydrology.展开更多
The effect of four bottom substrates, oyster shell powder(OP), sugarcane bagasse(SB), a mixture of OP and SB(OS) and fresh soil(FS), on the water quality and bacterial and zooplankton density of intensive shrimp(Litop...The effect of four bottom substrates, oyster shell powder(OP), sugarcane bagasse(SB), a mixture of OP and SB(OS) and fresh soil(FS), on the water quality and bacterial and zooplankton density of intensive shrimp(Litopenaeus vannamei) culture tanks without water change and the growth performance of cultured shrimp were compared in this study. At the end of a 110 days culturing trial, the total ammonium-N(TAN) of the water on SB and the nitrite nitrogen(NO2-N) on OS was significantly lower than that on the other substrates(P<0.05), which coincided with the high density of ammonium- and nitrite-oxidizing bacteria in the water on SB and OS, respectively. The concentration of chlorophyll a(Chl a) increased slowly on OP, SB and OS but remained low on FS. The density of total bacteria on OP, SB and OS was one order of magnitude higher than that on FS, and the density of zooplankton on SB and OS was significantly higher than that on FS or OP(P<0.05). The improved water quality and increased density of bacteria and zooplankton on SB and OS may have had a synergistic effect on shrimp culture, improving its growth performance(high survival rate and yield and low feed conversion rate). SB and OS were more effective for improving the growth performance of intensively cultured L. vannamei without water change than OP and FS. To our knowledge, this study presents the first evidence regarding the effect of different bottom substrates on intensive shrimp culture.展开更多
Selective breeding of the Pacific white shrimp Litopenaeus vannamei during the last decade has produced new varieties exhibiting high growth rates and disease resistance.However,the identification of new varieties of ...Selective breeding of the Pacific white shrimp Litopenaeus vannamei during the last decade has produced new varieties exhibiting high growth rates and disease resistance.However,the identification of new varieties of shrimps from their phenotypic characters is difficult.This study introduces a new approach for identifying varieties of shrimps using molecular markers of microsatellites and mitochondrial control region sequences.The method was employed to identify a new selected variety,Kehai No.1(KH-1),from three representative stocks(control group):Zhengda;Tongwei;and a stock collected from Fujian Province,which is now cultured in China's Mainland.By pooled genotyping of KH-1 and the control group,five microsatellites showing differences between KH-1 and the control group were screened out.Individual genotyping data confirmed the results from pooled genotyping.The genotyping data for the five microsatellites were applied to the assignment analysis of the KH-1 group and the control group using the partial Bayesian assignment method in GENECLASS2.By sequencing the mitochondrial control regions of individuals from the KH-1 and control group,four haplotypes were observed in the KH-1 group,whereas14 haplotypes were obtained in the control group.By combining the microsatellite assignment analysis with mitochondrial control region analysis,the average accuracy of identification of individuals in the KH-1group and control group reached 89%.The five selected microsatellite loci and mitochondrial control region sequences were highly polymorphic and could be used to distinguish new selected varieties of L.vannamei from other populations cultured in China.展开更多
Litopenaeus vannamei, a euryhaline species, can be cultured at a wide range of salinities. The emergence of freshwater pond-culture ofL. vannamei is an important prelude to the continued development of shrimp culture ...Litopenaeus vannamei, a euryhaline species, can be cultured at a wide range of salinities. The emergence of freshwater pond-culture ofL. vannamei is an important prelude to the continued development of shrimp culture in China. In this study, we com- pared the respiratory metabolism of juvenile L. vannamei cultured in freshwater and saltwater by measuring their oxygen consump-tion rate （OCR）, ammonium-type nitrogen excretion rate （AER） and pyruvate kinase （PK） and lactate dehydrogenase （LDH） activi-ties at different molting stages in order to physiecologically characterize juvenile L. vannamei under freshwater conditions. The re- suits showed that OCR was significantly higher in saltwater than in freshwater at all stages of molting cycle. However, variation of OCR among molting stages in saltwater was similar with that in freshwater, and the highest OCR was observed at post-molting stage. At all stages of molting cycle, AER was significantly higher in freshwater than in saltwater, and the highest was observed at post-molting stage. The activity of PK was significantly higher in saltwater than in freshwater. Conversely, the activity of LDH was higher in freshwater than in saltwater in general. Significant variation of PK and LDH activities in molting cycle was observed in saltwater and freshwater. The results indicated that aerobic metabolism of juvenile L. vannamei was more active in saltwater than in freshwater; while its protein metabolism was more active in freshwater than in saltwater.展开更多
Water scarcity is a major problem for Namibia and South Africa as both countries are classified as ＂water stressed＂, based on their per capita water availability which is below the threshold of 1,000-1,666 ma-person...Water scarcity is a major problem for Namibia and South Africa as both countries are classified as ＂water stressed＂, based on their per capita water availability which is below the threshold of 1,000-1,666 ma-person^-1.year^-1. Water provision in both countries has traditionally relied on supply-side sources, and the potential for expansion is becoming dim, making efforts towards demand management approaches more feasible. Findings show that CBM （community based management） systems of water points offer an alternative in terms of ownership and self-reliance based on institutional arrangements at community level. However, the CBM system involves some forms of payment for water access, and affordability has become a main challenge, to the extent that some governments are considering the reintroduction of water subsidies for poor rural communities in the near future.展开更多
A pot culture experiment was carried out to study the interaction of Melodogyne incognita and Fusarium chlamydosporurn on Coleus forskohlii. The nematode multiplication was adversely affected when fungus was inoculate...A pot culture experiment was carried out to study the interaction of Melodogyne incognita and Fusarium chlamydosporurn on Coleus forskohlii. The nematode multiplication was adversely affected when fungus was inoculated prior to nematode. Simultaneous inoculation of nematode and fungus as well as nematode followed by fungus seven days later, caused 85.5 per cent root rot disease and significant reduction in plant growth as well as nematode multiplication when compared to the inoculation fungus alone or fungus inoculation prior to nematode.展开更多
Benapenem is a new parenteral beta-lactam antibacterial with a broad antibacterial spectrum. In the present study, we developed and validated a simple, rapid and sensitive assay method using D6-benapenem as internal s...Benapenem is a new parenteral beta-lactam antibacterial with a broad antibacterial spectrum. In the present study, we developed and validated a simple, rapid and sensitive assay method using D6-benapenem as internal standard(IS) after one-step precipitation with methanol to determine benapenem in the plasma of infected mice. Separation was achieved on a reverse phase C18 column with a mobile phase composed of acetonitrile containing 0.2% formic acid–water(0.2% formic acid) and 10 mmol/L ammonium acetate in gradient elution mode. A triple quadrupole tandem mass spectrometer with electrospray ionization source was used as detector and operated by multiple reaction monitoring(MRM) in the positive ion mode. Calibration curves were linear(r>0.99) between 10 and 2000 ng/m L. The quantitative limit was 10 ng/m L, and the intra-and inter-precisions were <4.85% and <1.47%, respectively. The extraction recovery of benapenem and IS was 97.07%–107.09% and 92.47%–111.59%, respectively. The intra-and inter-accuracies were –9.70%– –11.00%, and the matrix effects of benapenem and IS were 85.68%–92.04% and 83.17%–92.04%, respectively. The method was successfully applied to the preclinical pharmacokinetic(PK) studies of benapenem. We also developed a two-compartment model to characterize the PK profiles of benapenem in infected mice, which could provide a better understanding of the PK properties of benapenem.展开更多
The current economic crisis has left numerous residential developments in the southeastern United States in various stages of construction. Many of them are currently graded and essentially abandoned, creating a major...The current economic crisis has left numerous residential developments in the southeastern United States in various stages of construction. Many of them are currently graded and essentially abandoned, creating a major source of sediment runoff to waterways. Residential development locations with significant bare soil areas were identified through classification of Landsat 5 TM satellite imagery and subsequently verified from high-resolution county aerial photographs. The revised universal soil loss equation (RUSLE) was used in a geographic information system (GIS) as a tool for prioritizing identified locations on the basis of potential soil loss assuming the worst case scenario of a completely unmaintained site. Initial GIS identification indicated 301 sites with a total bare soil area of 2 378 ha over three counties in Upstate South Carolina. A random sample of 153 sites was visited over 17 days and assessed using a mobile GIS, global positioning system (GPS), and digital camera for field validation. Results indicated that 78% (119) of the sites were classified correctly (residential construction sites in varying stages of completion); 88% of identified areas were less than 25% built compared to the previous year; 48% were categorized as moderate to severe problems. Abandoned and unfinished developments in Upstate South Carolina may represent a major source of sediment pollution to streams. Well-maintained erosion control devices may be useful in preventing offsite sedimentation.展开更多
文摘[Objective] The aim was to observe the antibacterial effect of nano-scale Titanium dioxide on parasitic bacterium of Nanfeng Citrus in storage period.[Method] Nano-scale Titanium dioxide was prepared by dibutyl phthalate through sol-gel method under anhydrous conditions,and orthogonal experiment was used to determine optimum conditions for nano-scale Titanium dioxide preparation,and structure characterization of nano-scale Titanium dioxide was carried out by X-Ray diffractometer.Oxford cup method was used to explore inhibition effect of nano-scale Titanium dioxide suspension on the activity of normal parasitic bacterium of Nanfeng Citrus.Simultaneously,the empirical preservation test was carried out.[Result] The average diameter of nano-scale Titanium dioxide powder attained to 14.6 nm,actual average yield could reach 90.83% with RSD（Relative Standard Deviation）of 0.86%.[Conclusion] Nano-scale Titanium dioxide had good antibacterial effect on the parasitic bacterium of Nanfeng Citrus in storage period.
基金Supported by Yunnan Scientific and Planned Project (2009ZC084M)Scientific and Planned Project of Yunnan Educational Department (08C0093)+1 种基金Key Subject Construction Project of Southwest Forestry University (XKX200902)National Natural Science Foundation of China (30170168)~~
文摘[Objective] The aim was to study on biological characteristics of photosynthetic response for young trees of B. macrostachya in seasonal rain forest, providing scientific reference for protection of tropical rain forest under change of global climate. [Method] Young trees of B. macrostachya in Xishuangbanna tropical forest were chosen to research in foggy season, dry and hot season, and rainy season to measure dynamics of season changes. [Result] For young trees of B. macrostachya in Yunnan Province, Pn max was the biggest in rainy season, followed by dry and hot season and foggy season at 4.08, 2.89 and 1.81 μmol/（m·s） respectively; Gs and Tr in rainy season were the highest and WUE in dry season was the highest; Gi achieved peak in foggy season, of which the highest values were 0.18 and 1.59 mmol/（m 2 ·s）, and 7.35 μmol/mmol and 455 mmol/（m 2 ·s）; Ci showed an opposite trend with that of WUE, and Gs and Tr changed similarly. [Conclusion] Young trees of B. macrostachya in seasonal rain forest are of significant seasonal change in photosynthetic response, and young trees are shade tolerant.
文摘According to the Energy Information Administration, average retail gasoline prices tend to typically be higher in certain states than in others. Aside from taxes, the factors shown to contribute to regional and even local differences in gasoline prices include proximity of supply, supply disruptions, competition in the local market and environmental programs. Of interest in this paper is proximity of supply. It has been hypothesized that areas farthest from the Gulf Coast （the source of nearly half of the gasoline produced in the United States and, thus, a major supplier to the rest of the country） tend to have higher prices. To test this hypothesis, the paper assembles state level monthly retail gasoline data for the period 1983 to 2007 for five states with oil refineries （Alabama, Georgia, Texas, Mississippi and Louisiana） and five states without refineries （Arkansas, Tennessee, North Carolina, South Carolina and Florida）. The analysis employs dynamic correlation, regression, cointegration and vector autoregressive methods. Overall, the results show that retail gas prices in states with refineries and those without refineries tend to move in the same direction over time. The small differences observed over time may suggest that price shocks take a short time to be felt nationwide.
文摘The issues and challenges of minimum adequate public school education in the State of South of South Carolina has been a struggle between lawmakers and taxpayers for more than fifty years. The enactment of the Civil Rights Act of 1964 led to forced school integration, busing, and led to whites＇ physical moving out of selected school districts. Selected public schools filed a lawsuit against the State of South Carolina to the Supreme Court with the claim of failing to provide adequate and equal education to all children in the state. This reflection focuses on the Abbeville case in context, funding issues, and inadequate facilities, which concludes with a reflective view of the Brown v. The Board of Edueation 1954 decision.
基金Development Plan for Key National Foundation Research (Project 973 and 2003CB415100)Natural Science Foundation of Yunnan Province (2003C0002Z)
文摘1 INTRODUCTION As one of the main factors affecting input and use of precipitation by forests, rainfall also makes a difference on partitioning of gross precipitation over the canopy, equilibrium of water amount in river basins and water cycling processes . In view of its poorlydefined four seasons in contrast to well-defined dry and wet spells in addition to its inland location, understanding of precipitation characteristics and tendencies is important for the study on local forestry hydrology. Relevant research has been documented, but few have dealt with multiple time scales at the hourly, daily, monthly and annual intervals. With the 1992 - 2003 automatic record of precipitation in Menglun, Xishuangbannan analyzed, its characteristics and trends are summarized to help in the study on forestry hydrology.
基金supported by National Science and Technology Supporting Program of the Twelfth Five-Year Plan of China (2011BAD13B10)the Special Fund for Agro-scientific Research in the Public Interest, China (201103034)
文摘The effect of four bottom substrates, oyster shell powder(OP), sugarcane bagasse(SB), a mixture of OP and SB(OS) and fresh soil(FS), on the water quality and bacterial and zooplankton density of intensive shrimp(Litopenaeus vannamei) culture tanks without water change and the growth performance of cultured shrimp were compared in this study. At the end of a 110 days culturing trial, the total ammonium-N(TAN) of the water on SB and the nitrite nitrogen(NO2-N) on OS was significantly lower than that on the other substrates(P<0.05), which coincided with the high density of ammonium- and nitrite-oxidizing bacteria in the water on SB and OS, respectively. The concentration of chlorophyll a(Chl a) increased slowly on OP, SB and OS but remained low on FS. The density of total bacteria on OP, SB and OS was one order of magnitude higher than that on FS, and the density of zooplankton on SB and OS was significantly higher than that on FS or OP(P<0.05). The improved water quality and increased density of bacteria and zooplankton on SB and OS may have had a synergistic effect on shrimp culture, improving its growth performance(high survival rate and yield and low feed conversion rate). SB and OS were more effective for improving the growth performance of intensively cultured L. vannamei without water change than OP and FS. To our knowledge, this study presents the first evidence regarding the effect of different bottom substrates on intensive shrimp culture.
基金Supported by the National High Technology Research and Development Program of China(863 Program)(Nos.2012AA10A404,2012AA092205)
文摘Selective breeding of the Pacific white shrimp Litopenaeus vannamei during the last decade has produced new varieties exhibiting high growth rates and disease resistance.However,the identification of new varieties of shrimps from their phenotypic characters is difficult.This study introduces a new approach for identifying varieties of shrimps using molecular markers of microsatellites and mitochondrial control region sequences.The method was employed to identify a new selected variety,Kehai No.1(KH-1),from three representative stocks(control group):Zhengda;Tongwei;and a stock collected from Fujian Province,which is now cultured in China's Mainland.By pooled genotyping of KH-1 and the control group,five microsatellites showing differences between KH-1 and the control group were screened out.Individual genotyping data confirmed the results from pooled genotyping.The genotyping data for the five microsatellites were applied to the assignment analysis of the KH-1 group and the control group using the partial Bayesian assignment method in GENECLASS2.By sequencing the mitochondrial control regions of individuals from the KH-1 and control group,four haplotypes were observed in the KH-1 group,whereas14 haplotypes were obtained in the control group.By combining the microsatellite assignment analysis with mitochondrial control region analysis,the average accuracy of identification of individuals in the KH-1group and control group reached 89%.The five selected microsatellite loci and mitochondrial control region sequences were highly polymorphic and could be used to distinguish new selected varieties of L.vannamei from other populations cultured in China.
基金supported by National Program on Key Basic Research Project (Grant No.2009CB118706)
文摘Litopenaeus vannamei, a euryhaline species, can be cultured at a wide range of salinities. The emergence of freshwater pond-culture ofL. vannamei is an important prelude to the continued development of shrimp culture in China. In this study, we com- pared the respiratory metabolism of juvenile L. vannamei cultured in freshwater and saltwater by measuring their oxygen consump-tion rate （OCR）, ammonium-type nitrogen excretion rate （AER） and pyruvate kinase （PK） and lactate dehydrogenase （LDH） activi-ties at different molting stages in order to physiecologically characterize juvenile L. vannamei under freshwater conditions. The re- suits showed that OCR was significantly higher in saltwater than in freshwater at all stages of molting cycle. However, variation of OCR among molting stages in saltwater was similar with that in freshwater, and the highest OCR was observed at post-molting stage. At all stages of molting cycle, AER was significantly higher in freshwater than in saltwater, and the highest was observed at post-molting stage. The activity of PK was significantly higher in saltwater than in freshwater. Conversely, the activity of LDH was higher in freshwater than in saltwater in general. Significant variation of PK and LDH activities in molting cycle was observed in saltwater and freshwater. The results indicated that aerobic metabolism of juvenile L. vannamei was more active in saltwater than in freshwater; while its protein metabolism was more active in freshwater than in saltwater.
文摘Water scarcity is a major problem for Namibia and South Africa as both countries are classified as ＂water stressed＂, based on their per capita water availability which is below the threshold of 1,000-1,666 ma-person^-1.year^-1. Water provision in both countries has traditionally relied on supply-side sources, and the potential for expansion is becoming dim, making efforts towards demand management approaches more feasible. Findings show that CBM （community based management） systems of water points offer an alternative in terms of ownership and self-reliance based on institutional arrangements at community level. However, the CBM system involves some forms of payment for water access, and affordability has become a main challenge, to the extent that some governments are considering the reintroduction of water subsidies for poor rural communities in the near future.
文摘A pot culture experiment was carried out to study the interaction of Melodogyne incognita and Fusarium chlamydosporurn on Coleus forskohlii. The nematode multiplication was adversely affected when fungus was inoculated prior to nematode. Simultaneous inoculation of nematode and fungus as well as nematode followed by fungus seven days later, caused 85.5 per cent root rot disease and significant reduction in plant growth as well as nematode multiplication when compared to the inoculation fungus alone or fungus inoculation prior to nematode.
基金National Natural Science Foundation of China(Grant No.81803614)
文摘Benapenem is a new parenteral beta-lactam antibacterial with a broad antibacterial spectrum. In the present study, we developed and validated a simple, rapid and sensitive assay method using D6-benapenem as internal standard(IS) after one-step precipitation with methanol to determine benapenem in the plasma of infected mice. Separation was achieved on a reverse phase C18 column with a mobile phase composed of acetonitrile containing 0.2% formic acid–water(0.2% formic acid) and 10 mmol/L ammonium acetate in gradient elution mode. A triple quadrupole tandem mass spectrometer with electrospray ionization source was used as detector and operated by multiple reaction monitoring(MRM) in the positive ion mode. Calibration curves were linear(r>0.99) between 10 and 2000 ng/m L. The quantitative limit was 10 ng/m L, and the intra-and inter-precisions were <4.85% and <1.47%, respectively. The extraction recovery of benapenem and IS was 97.07%–107.09% and 92.47%–111.59%, respectively. The intra-and inter-accuracies were –9.70%– –11.00%, and the matrix effects of benapenem and IS were 85.68%–92.04% and 83.17%–92.04%, respectively. The method was successfully applied to the preclinical pharmacokinetic(PK) studies of benapenem. We also developed a two-compartment model to characterize the PK profiles of benapenem in infected mice, which could provide a better understanding of the PK properties of benapenem.
基金Supported by the South Carolina Water Resources Centerthe Clemson University Public Service and Agriculture Next Generation Graduate Fellowship (PSA-NGGF), USATechnical Contribution No. 5903 of the Clemson University Experiment Station, USA
文摘The current economic crisis has left numerous residential developments in the southeastern United States in various stages of construction. Many of them are currently graded and essentially abandoned, creating a major source of sediment runoff to waterways. Residential development locations with significant bare soil areas were identified through classification of Landsat 5 TM satellite imagery and subsequently verified from high-resolution county aerial photographs. The revised universal soil loss equation (RUSLE) was used in a geographic information system (GIS) as a tool for prioritizing identified locations on the basis of potential soil loss assuming the worst case scenario of a completely unmaintained site. Initial GIS identification indicated 301 sites with a total bare soil area of 2 378 ha over three counties in Upstate South Carolina. A random sample of 153 sites was visited over 17 days and assessed using a mobile GIS, global positioning system (GPS), and digital camera for field validation. Results indicated that 78% (119) of the sites were classified correctly (residential construction sites in varying stages of completion); 88% of identified areas were less than 25% built compared to the previous year; 48% were categorized as moderate to severe problems. Abandoned and unfinished developments in Upstate South Carolina may represent a major source of sediment pollution to streams. Well-maintained erosion control devices may be useful in preventing offsite sedimentation.
