Both abiotic conditions and management influence the success of forest restoration.Despite growing interest and practical effort in restoring degraded forest landscapes,understanding of how disparate factors,such as t...Both abiotic conditions and management influence the success of forest restoration.Despite growing interest and practical effort in restoring degraded forest landscapes,understanding of how disparate factors,such as terrain,soil conditions,climate and silvicultural treatments,directly or collectively control species performance and shape community recovery remains limited.In this study,we assessed how topography and management intervention affect seedling survival and growth in the early stages of restoration.To do so,we established seven experimental plots,each measuring 20 m×20 m(400 m2)subdivided into 48 subplots,in coarse,anthropogenic grassland on a mid-elevation mountain slope in Hong Kong,and planted a total of 3975 native tree seedlings belonging to 12 tree species within them.To characterise topography,we modelled the elevation,slope,convexity and aspect of each subplot.Two types of tree guard(enclosed blue plastic sleeve and open yellow mesh),two types of fertiliser(organic and inorganic)and cardboard weeding mats were used to assess the impact of management interventions on the establishment of the seedlings.Survivorship,height and basal diameter were measured at 1,2 and 4 years after planting.We used generalised linear models to examine the effect of these factors and their interactions on seedling survival,and we applied linear models and hierarchical partitioning to explore their relative importance in determining the relative growth rate(RGR)of each species.The most parsimonious models were selected using the Akaike Information Criterion.Survivorship was 98.1%,95.2%and 86.4%across all plots in the first,second and fourth year,respectively.On average,topographic and management variables explained 1.48–3.34%of total variation in RGR,respectively,for all species.The models revealed that type of tree guard,aspect and elevation were the most important factors explaining RGR and survival.Results of hierarchical partitioning by species and growth period showed that the key determinants of performance vary by species and shift over the course of early seedling establishment,emphasising the importance of both spatial and temporal scales in the restoration of degraded tropical forests.Our findings support the use of enclosed tree guards and fertiliser to improve survivorship and growth across a range of broadleaved Asiatic species.All potential limiting factors pertaining to both site factors and management,as well as their interactions,should be considered in restoration planning to maximise restoration success.展开更多
Background: Inland wetlands are crucial for biodiversity conservation, especially in highly-urbanized landscapes. In the European Union, many wetlands are included in the EU ‘Natura 2000’ network, the main tool for ...Background: Inland wetlands are crucial for biodiversity conservation, especially in highly-urbanized landscapes. In the European Union, many wetlands are included in the EU ‘Natura 2000’ network, the main tool for biodiversity conservation over the continent, which requires the development of site-specific management plans. Clear and feasible recommendations are necessary to provide site managers with effective tools for the maintenance of biodiversity in these unstable environments. Birds are excellent umbrella species, therefore a management targeted at increasing habitat suitability for focal bird species would likely benefit broader wetland biological communities. Methods: During spring–summer 2017, we collected presence/absence data for 10 bird species of conservation interest at a site scale for 21 Natura 2000 sites. We also carried out a point count survey to detect presence/absence of four reedbed-dwelling species at 75 points. At the site level, we estimated landscape characteristics from regional GISlayers, whereas fine-scaled habitat composition was recorded on the field within a 100 m-buffer around the 75 points. We analysed the effect of the extent of different habitats on species’ occurrence probability by means of multi-species binomial multivariate adaptive regression splines (MARS) at both scales. We also run species-specific MARS models to compare their performance with those of multi-species models. Results: At the site scale, the extent of the reedbeds/mires was positively associated with the occurrence of all species of conservation concern. At the point-count scale, reedbed extent positively predicted species’ occurrence, but only in presence of patches of clear shallow water. Species-specific MARS models showed qualitatively similar results for some species, but generally were outperformed by multi-species ones. Conclusions: Multi-species MARS models confirmed to be an efficient tool in disclosing species-habitat relationships even for set of species including scarce taxa and when only short-term monitoring data are available. In terms of conservation measures, our findings stress the importance of Phragmites australis reedbed as a key habitat for avian biodiversity, but only when it is flooded and interspersed with scattered patches of open water. The preservation of wide (>100/150 ha) and flooded reedbeds structured in spots of no less than 2 ha emerges as the main conservation measure for the long-term conservation of the threatened avifauna of inland pre-Alpine wetlands.展开更多
We surveyed the distribution, composition and diversity of freshwater fish in Hong Kong, China from 2002 to 2004. Sites surveyed were mainly streams, marshes and estuaries. There are ponds for aquaculture and reservoi...We surveyed the distribution, composition and diversity of freshwater fish in Hong Kong, China from 2002 to 2004. Sites surveyed were mainly streams, marshes and estuaries. There are ponds for aquaculture and reservoirs in Hong Kong but no large natural water bodies. From the 220 sites surveyed, 114 species of 37 families were found. Gobiidae (with 24 species) and Cyprinidae (21 species) were the dominant families. This survey has increased the number of freshwater fish species recorded in Hong Kong to 167. Among these, 71 (42.5%) are primary freshwater fish, 44 are brackish and 46 are vagrants. The remaining 6 species are diadromous. In Hong Kong, freshwater fish are conserved by a combination of measures. About 38% of Hong Kong’s land area is designated as country parks and/or special areas, and is managed for nature conservation and educational purposes. In addition, another 5% of land area is zoned for conservation in the statutory land use zoning system to protect them from development and incompatible land uses. Major development projects have to go through the statutory environmental impact assessment process to ensure that they will not have adverse impact as far as practicable. There are conservation action plans for important species. For example, captive-bred individuals of the endemic Hong Kong Paradise Fish Macropodus hongkongensis have been released to suitable and secure sites inside country parks and their populations are regularly monitored. Other measures such as wetland creation, restoration and enhancement programmes are also implemented for freshwater fish conservation.展开更多
The Red-footed Falcon(Falco vespertinus)is a species of high international conservation interest.We analyzed its hunting behavior at the two largest colonies in Italy during the nestling period.Using accurate data-log...The Red-footed Falcon(Falco vespertinus)is a species of high international conservation interest.We analyzed its hunting behavior at the two largest colonies in Italy during the nestling period.Using accurate data-loggers,we tracked three adult Red-footed Falcons in June and July,2019 and collected 4703 GPS points.We detected clear patterns of hovering and perching activity(HPA)in both time and space.HPA occupied one-third of the Red-footed Falcons’day,and showed two peaks just after sunrise(between 35 and 40%of the monitoring time)and just before sunset(50‒60%)in both June and July,and minimum(20‒30%)at night and during the hottest time interval(10:00 a.m.‒4:00 p.m.).Almost 40%of HPA occurred within 50 m from nests.Our findings,although preliminary,have important implications for the conservation of these two colonies that are located within two Natura 2000 sites.The detected spatio-temporal patterns of Red-footed Falcons’hunting behavior suggests the creation of two nested protection belts:the inner one is a narrow belt(up to 50 m from the two rows of trees that host the two colonies)with integral conservation,and hopefully increase the alfalfa crops and fallow land,and the outer belt(50 m‒2 km)with optimized agricultural activities.展开更多
During this study, the principal aim carried out was to obtain more information about technique and conservation conditions of the Egyptian wall paintings during the Roman period in the funerary house in necropolis of...During this study, the principal aim carried out was to obtain more information about technique and conservation conditions of the Egyptian wall paintings during the Roman period in the funerary house in necropolis of Tuna el-Gabal, El-Minia-Upper Egypt. It’s going back to 2nd century AD and involves different sites of Ptolemaic and Roman chapels;some are in the immaculate established style while others are a blend of Pharaonic-Greek style and both are secured with mural painting. Deterioration problems observed on the wall paintings of the funerary house are, loss of plaster layers, disintegration of plaster layers, loss of paint layers (blistering and peeling), discoloration and severely damaged owing to a lot of deterioration factors as weakness of mud brick support, deterioration of surface treatments and to the widespread presence of different salts. The materials used in the painting, preparation layers and the state of conservation of the mural painting at funerary house were investigated by integrated physio-chemical measurements, particularly micro-Raman spectroscopy (µRaman), light optical microscopy (LOM), scanning electron microscopy (SEM) coupled with an energy dispersive X-ray analysis system (EDX), X-ray powder diffraction (XRD) and Fourier transform infrared (FT-IR). In addition, the morphology of multilayer plaster from wall painting was investigated using atomic force microscopy (AFM). A wide color palette utilized as a part of the necropolis has been identified with mineral pigments and pigment mixtures. It is found that, the paints were based on an organic binder and traditional pigments (azurite, hematite, ochre, vegetable black) were used as colorants on plaster. The examination demonstrated that the preparatory layer is verging on made of pure lime while the plaster layer based mainly of lime and gypsum with variable amounts of quartz. The obtained results provided information about the painting technique, chemical composition, crystal structure in addition to the stratigraphy of the paint layers and the state of preservation and on the causes of the painting deterioration. Furthermore, the obtained results can be used in the conservation and restoration interventions of these sites.展开更多
The Roman Period temple of Isis at Shenhur was built and enhanced amid the rule of Augustus (30 BCE-14 CE) through that of Trajan (98-117 CE). It was built of two sorts of local limestone and decorated with reliefs. E...The Roman Period temple of Isis at Shenhur was built and enhanced amid the rule of Augustus (30 BCE-14 CE) through that of Trajan (98-117 CE). It was built of two sorts of local limestone and decorated with reliefs. Examination of conservation state uncovered that it was collapsed and only partly preserved and it disposed of some still buried rooms. The temple is exposed to different deteriorations processes created by internal and external stresses because of the mineral composition of the building materials, atmosphere variables, salts crystallization and groundwater. In this study, the deterioration problems of the wall reliefs were examined for the aim of its conservation. For this purpose, the chemical, physical and structural characterization were performed by means of X-Ray Diffraction (XRD) and observation of thin section by transmitted light optical microscopy (LOM), polarized microscope, Scanning Electron Microscope (SEM) attached with EDX and thermogravimetric (DTA & TGA). Additionally, microbiological study and chemical analyses of ground water were carried out. Results demonstrated that the deterioration of Shenhur was because of the forceful activity of the environment agents and soluble salts such as chlorides and sulphates. These results and information allowed that the identification of the types of salts and deterioration features might be used in the future for conservation purposes.展开更多
Helal El-Beah mosque in Egypt was built from many different materials as sandstone, bricks and marble. These building materials were in a bad condition due to many degradation factors, mainly ground water and salt wea...Helal El-Beah mosque in Egypt was built from many different materials as sandstone, bricks and marble. These building materials were in a bad condition due to many degradation factors, mainly ground water and salt weathering, so many deterioration phenomena were appeared as horizontal and vertical cracks, salts, loss of the Islamic decorations in the fa?ade and mihrab (Prayer niche), detachment of the plaster, biological colonization and featured dark of the stone surface. Prior to the conservation intervention, the building materials were characterized to identify their components. Scientific conservation treatment was carried out for the long-term conservation of the mosque. Conservation operations at the mosque included: repairing and roof insulation, wet and dry cleaning, joining of cracked parts and surface consolidating, replacement of the Portland cement plaster with lime plaster, re-cladding the lower part of the interior brick walls with sandstone tiles, replacement and completion of the stone blocks.展开更多
SWAT model is one of the primary tools for assessing irrigation district water management and water-saving measures.However,its incapacity to consider the diverse growth and water requirements of paddy during various ...SWAT model is one of the primary tools for assessing irrigation district water management and water-saving measures.However,its incapacity to consider the diverse growth and water requirements of paddy during various growth stages,as well as the insufficient availability of external water sources.This study introduces the Penman-Monteith equation and Jensen model into the SWAT framework,setting crop coefficients,crop base coefficients,and growth stage sensitivity indices based on the different growth stage.Additionally,modifications are made to the external water source available for irrigation and paddyfield leakage modules,establishing a distributed agricultural hydrological model suitable for accurately simulating water balance elements and paddy yield in multi-source irrigation districts.The Yangshudang watershed in the Zhanghe irrigation district is chosen for the evaluation of the modified model's simulation performance,with a quantitative assessment of water-saving and yield-increasing effects.The results demonstrate that the modified model effectively meets the requirements for simulating paddy evapotranspiration of various growth stages,yield,agricultural irrigation water consumptions,and runoff,exhibiting a notable enhancement in performance.As two common water-saving measures in irrigation areas,inter-mittent irrigation and irrigation district renovation were used as two water-saving scenarios in the simulation of the modified SWAT model.Under intermittent irrigation,the watershed experiences a 6.58%reduction in net irrigation water use.In the scenario with irrigation district renovation,the water resources in the watershed are utilized more efficiently.The modified model from this study can be applied for assessing the synergistic effects of irrigation district water-saving and yield-increasing measures,providing crucial insights for the formulation of irri-gation district water-saving strategies and water resource optimization plans.展开更多
通过对黑土坡耕地免耕、少耕与传统耕作土壤物理性状全生育期观测，比较研究土壤结构和导水性状季节变化差异及其与水土流失的关系。结果表明，表层0～20 cm土壤，免耕土壤容重全生育期维持在1.20～1.30 g cm^-3，变化小，大于0.25 mm...通过对黑土坡耕地免耕、少耕与传统耕作土壤物理性状全生育期观测，比较研究土壤结构和导水性状季节变化差异及其与水土流失的关系。结果表明，表层0～20 cm土壤，免耕土壤容重全生育期维持在1.20～1.30 g cm^-3，变化小，大于0.25 mm的水稳性团聚体含量（WR0.25）和平均重量直径（MWD）高于传统耕作，初始和稳定入渗速率均高于少耕和传统耕作，土壤含水量分别较少耕和传统耕作高4.7和4.4个百分点，较传统耕作分别减少地表径流和土壤流失量86%和100%；少耕除夏季各项性状均介于免耕和传统耕作之间，夏季垄沟深松后，垄沟土壤容重显著降低，较免耕和传统耕作降低0.15 g cm^-3以上，提高土壤初始入渗速率30%以上，较传统耕作减少水和土壤流失量20%和40%。传统耕作土壤容重，垄台由播种时的0.91 g cm^-3增加至收获时的1.23 g cm^-3，垄沟一直维持在1.30 g cm^-3左右，WR0.25、MWD、土壤稳定入渗速率、含水量均较低，全生育期10%的雨水流失，土壤流失量615 t km^-2 a^-1。免耕土壤结构稳定，蓄水保水最佳，为效果显著的水土保持耕作措施，少耕也有一定的保水保土作用；免耕和少耕均能够改善土壤物理性状。展开更多
Aggregate stability is a very important predictor of soil structure and strength, which influences soil erodibility. Several aggregate stability indices were selected erodibility of four soil properties from temperate...Aggregate stability is a very important predictor of soil structure and strength, which influences soil erodibility. Several aggregate stability indices were selected erodibility of four soil properties from temperate for estimating interrill types with contrasting and subtropical regions of China. This study was conducted to investigate how closely the soil interrill erodibility factor in the Water Erosion Prediction Project （WEPP） model relates to soil aggregate stability. The mass fractal dimension （FD）, geometric mean diameter （GMD）, mean weight diameter （MWD）, and aggregate stability index （ASI） of soil aggregates were calculated. A rainfall simulator with a drainable flume （3.0 m long × 1.0 m wide × 0.5 m deep） was used at four slope gradients （5°,10 °,15° and 20°）, and four rainfall intensities （0.6, 1.1, 1.7 and 2.5 mm/min）. Results indicated that the interriU erodibility （Ki） values were significantly correlated to the indices of ASI, MWD, GMD, and FD computed from the aggregate wet-sieve data. The Kihad a strong positive correlation with FD, as well as a strong negative correlation with ASI, GMD, and MWD. Soils with a higher aggregate stability and lower fractal dimension have smaller Ki values. Stable soils were characterized by a high percentage of large aggregates and the erodible soils by a high percentage of smaller aggregates. The correlation coefficients of Ki with ASI and GMD were greater than those with FD and MWD, implying that both the ASI and GMD may be better alternative parameters for empirically predicting the soil Ki factor. ASI and GMD are more reasonable in interrill soil erodibility estimation, compared with Ki calculation in original WEPP model equation. Results demonstrate the validation of soil aggregation characterization as an appropriate indicator of soil susceptibility to erosion in contrasting soil types in China.展开更多
According to the contemporary ecosystem approach, the linkages of human actions with their environment have to be assessed in an integrative manner. The Driver-Pressure-State-Impact-Response （DPSIR） model is applied...According to the contemporary ecosystem approach, the linkages of human actions with their environment have to be assessed in an integrative manner. The Driver-Pressure-State-Impact-Response （DPSIR） model is applied to identify and describe processes and interactions in human-environmental systems. An example application from a research project dealing with the development of sustainable management strategies for the agriculture in Jiangsu, China, illustrates the potentials and limitations of its sustainable development. The concept and indicators of ecological integrity are used to assess the indicators in the dimensions of DPSIR between 2003 and 2006. The main drivers included population growth which caused increasing demand for food, growing environmental demands, and rapidly decreasing of land and other natural resources. The main environmental problem was water pollution. The results show that in the dimension of driver, total grain output and agricultural land productivity both increased. Labor intensive agriculture has been promoted to increase agricultural land productivity. In the dimension of pressure, on the positive side, infrastructure got greatly improved, the input level such as total power of machinery, and level of fertilizer use increased, and level of pesticides use decreased, but on the negative side, cultivated land per capita and irrigation rate decreased, natural resources keep decreased. Environmental pollution indicators such as industrial wastewater discharge and acid rain rate increased in Jiangsu Province. In the aspect of state, ecosystem state was improved, plant coverage index increased, biological abundance index increased, fertilizer productivity increased, eco-environmental quality index increased, but land degradation index also increased. In the aspect of impact, output level increased, output efficiency enhanced, farmer＇s social economic benefit improved. In the aspect of response, social support was greatly improved, input for environmental governance increased. To assess the effects of environmental governance, Jiangsu government was successful to increase compliance rate of sulfur dioxide emissions, but not so efficient in compliance rate of industrial wastewater discharge.展开更多
Biological soil crusts(biocrusts)are important landscape components that exist in various climates and habitats.The roles of biocrusts in numerous soil processes have been predominantly recognized in many dryland regi...Biological soil crusts(biocrusts)are important landscape components that exist in various climates and habitats.The roles of biocrusts in numerous soil processes have been predominantly recognized in many dryland regions worldwide.However,little is known about their effects on soil detachment process by overland flow,especially in humid climates.This study quantified the effects of moss-dominated biocrusts on soil detachment capacity(Dc)and soil erosion resistance to flowing water in the Three Gorges Reservoir Area which holds a subtropical humid climate.Potential factors driving soil detachment variation and their influencing mechanism were analyzed and elucidated.We designed five levels of coverage treatments(1%–20%,20%–40%,40%–60%,60%–80%,and 80%–100%)and a nearby bare land as control in a mossdominated site.Undisturbed soil samples were taken and subjected to water flow scouring in a hydraulic flume under six shear stresses ranging from 4.89 to 17.99 Pa.The results indicated that mean Dc of mosscovered soil varied from 0.008 to 0.081 kg m^-2 s^-1,which was 1.9 to 21.0 times lower than that of bare soil(0.160 kg m^-2 s^-1).Rill erodibility(Kr)of mosscovered soil ranged from 0.0095 to 0.0009 s m^-1,which was 2 to 20 times lower than that of bare soil(0.0187 s m^-1).Both relative soil detachment rate and Kr showed an exponential decay with increasing moss coverage,whereas the critical shear stress(τc)for different moss coverage levels did not differ significantly.Moss coverage,soil cohesion,and sand content were key factors affecting Dc,while moss coverage and soil bulk density were key factors affecting Kr.A power function of flow shear stress,soil cohesion,and moss coverage fitted well to estimate Dc(NSE=0.947).Our findings implied that biocrusts prevented soil detachment directly by their physical cover and indirectly by soil properties modification.Biocrusts could be rehabilitated as a promising soil conservation measure during ecological recovery to enhance soil erosion resistance in the Three Gorges Reservoir Area.展开更多
Calcium hydroxide （CH） dressing residues can compromise endodontic sealing. This study aimed to evaluate the amount of remaining CH in root canals after mechanical removal by four groups of irrigation techniques inc...Calcium hydroxide （CH） dressing residues can compromise endodontic sealing. This study aimed to evaluate the amount of remaining CH in root canals after mechanical removal by four groups of irrigation techniques including needle irrigation only, ProTaper file, EndoActivator, and ultrasonic file. Fifteen extracted single-rooted teeth were collected and used for all four groups. The samples were firstly prepared by ProTaper rotary instruments, and then sectioned longitudinally through the long axis of the root canals, followed by final reassembling by wires. CH was kept in the canals for 7 days setting. The removal procedure began with 5 mL of 2.5% sodium hypochlorite （NaOC1） followed by 1 mL of 17% ethylenediaminetetraacetic acid and a final irrigation with 5 mL of 2.5% NaOC1 solution for all groups. No additional agitation of the irrigant was performed in group 1, while agitation for 20 s be- tween irrigants was done with F2 ProTaper rotary file in group 2, EndoActivator with tip size 25/.04 in group 3 and by an ultrasonic file 25/.02 in group 4. The total activation time was 60 s. The roots were then disassembled and captured by digital camera. The ratio of CH coated surface area to the surface area of the whole canal as well as each third of the canal was calculated. The data were statistically ana- lyzed by one-way ANOVA using post hoc Tukey test. Results showed that none of the four techniques could remove all CH. No significant difference was found between EndoActivator and ultrasonic tech- niques. However, they both removed significantly more CH than ProTaper and needle irrigation （P=0.0001）. In conclusion, the sonic and ultrasonic agitation techniques were more effective in removing intracanal medicaments than the ProTaper rotary file and needle irrigation in all thirds of the canal.展开更多
The dinoflagellate Noctiluca scintillans is one of the most important and abundant red tide organisms and it is distributed world-wide. It occurs in two forms. Red Noctiluca is heterotrophic and fills the role of one ...The dinoflagellate Noctiluca scintillans is one of the most important and abundant red tide organisms and it is distributed world-wide. It occurs in two forms. Red Noctiluca is heterotrophic and fills the role of one of the microzooplankton grazers in the foodweb. In contrast, green Noctiluca contains a photosynthetic symbiont Pedinomonas noctilucae （a prasinophyte）, but it also feeds on other plankton when the food supply is abundant. In this review, we document the global distribution of these two forms and include the first maps of their global distribution. Red Noctiluca occurs widely in the temperate to sub-tropical coastal regions of the world. It occurs over a wide temperature range of about 10℃ to 25℃ and at higher salinities （generally not in estuaries）. It is particularly abundant in high productivity areas such as upwelling or eutrophic areas where diatoms dominate since they are its preferred food source. Green Noctiluca is much more restricted to a temperature range of 25℃-30℃ and mainly occurs in tropical waters of Southeast Asia, Bay of Bengal （east coast of India）, in the eastern, western and northern Arabian Sea, the Red Sea, and recently it has become very abundant in the Gulf of Oman. Red and green Noctiluca do overlap in their distribution in the eastern, northern and western Arabian Sea with a seasonal shift from green Noctiluca in the cooler winter convective mixing, higher productivity season, to red Noctiluca in the more oligotrophic warmer summer season.展开更多
Annual discharge and annual suspended sediment loads of Beipei Hydrological Station of the Jialing River catchment were analyzed to describe the trend of Jialing River over the last five decades (1956-2006). These loa...Annual discharge and annual suspended sediment loads of Beipei Hydrological Station of the Jialing River catchment were analyzed to describe the trend of Jialing River over the last five decades (1956-2006). These loads were also analyzed to ascertain the influential factors associated with its variation with the help of Kendall's Tau-b correlation analysis and regression analysis. The results indicated that the Jialing River annual discharge showed no significant trend at >95% confidence level while the annual sediment load appeared to have a significant decrease trend over the last 50 years. A decrease in the annual sediment load was particularly apparent after the year 1985, at which a substantial shift in the sediment level occurred. This shift is attributed to the construction of numerous dams in 1980s. However, after the year of 1985, two periodical stages (1986-1991 and 1992-2006) with distinct sediment load and sediment-runoff ratio were identified. The period 1992-2006 is characterised by low sediment load, which is most probably due to the impact of large scale of soil and water conservation, which took place at the end of the 1980s. Last, models describing the relationship between the discharge and the sediment load, discharge and sediment-runoff ratio as well as between the sediment load and sediment-runoff ratio were constructed.展开更多
Since trees and plants can absorb CO2, forests are widely regarded as a carbon sink that may control the amount of CO2 in the atmosphere. The CO2 uptake rate of plants is affected by the plant species and environmenta...Since trees and plants can absorb CO2, forests are widely regarded as a carbon sink that may control the amount of CO2 in the atmosphere. The CO2 uptake rate of plants is affected by the plant species and environmental conditions such as photosynthetically active radiation (PAR), temperature, water and nutrient contents. PAR is the most immediate environmental control on photosynthesis while air temperature affects both photorespiration and dark respiration. In the natural condition, PAR and temperature play an important role in net CO2 uptake. The effects of PAR and air temperature on the CO2 uptake of Pterocarpus macrocarpus grown in a natural habitat were studied in the present work. Due to many uncontrollable factors, a simple rectangular hyperbola could not represent the measured data. The data were divided into groups of 2oC intervals; CO2 uptake in each group may then be related to PAR by a rectangular hyperbola function. Using the obtained functions, the effect of PAR was removed from the original data. The PAR-independent CO2 uptake was then related to air temperature. Finally, the effects of PAR (I) and air temperature (Ta) on the CO2 uptake rate (A) were combined as: (-0.0575Ta2+2.6691Ta-23.264)I A= ——————————————— (-0.00766Ta2+0.40666Ta-3.99924) (-4.8794Ta2+227.13Ta-2456.9)+I展开更多
[Objective] The aim was to study the main rainfall factors influencing runoff and sediment in the sloping farmland with different plants in the central south of Shandong Province.[Method] Through grey relational analy...[Objective] The aim was to study the main rainfall factors influencing runoff and sediment in the sloping farmland with different plants in the central south of Shandong Province.[Method] Through grey relational analysis,the effects of different rainfall factors on runoff and sediment with different plants in the central south of Shandong were studied.[Result] In the sloping farmland with different plants,the effects of rainfall factors on runoff and sediment weren’t consistent.Rainfall was the dominant influencing factor of runoff,but PI30 had the greatest influence on runoff in natural grassland.Meanwhile,rainfall intensity was the main influencing factor of sediment,but PI had the greatest influence on sediment in Astragalus adsurgens Pall.plot.The compound factor had the minimal influence on runoff and sediment in Arachis hypogaea plot and natural grassland.In A.adsurgens Pall.plot,rainfall intensity had the minimal impact on runoff,but the compound factor had the least effect on sediment.[Conclusion] The study could provide theoretical references for the comprehensive control of slope soil erosion,the optimum utilization and sustainable development of land.展开更多
N-（2,3-Dimethyl-phenyl）-N＇-（methoxyl formyl）thiourea was synthesized by the reacting of 2,3-dimethylaniline,potassium thiocyanate（KSCN） and methyl chloroformate（ClCOOCH 3）.Single crystal was obtained by slowl...N-（2,3-Dimethyl-phenyl）-N＇-（methoxyl formyl）thiourea was synthesized by the reacting of 2,3-dimethylaniline,potassium thiocyanate（KSCN） and methyl chloroformate（ClCOOCH 3）.Single crystal was obtained by slowly evaporation solvent at room temperature.The structure was characterized by elemental analysis,IR and X-ray crystalography.The compound crystallized：a triclinic system with space group Pī,a=0.83440（12） nm,b=0.89113（13） nm,c=0.93015（13） nm,α=76.548（2） o,β=63.906（2） o,γ=82.538（2） o,V=0.60379（15） nm 3,Z=2,D c =1.311 mg/m 3,F（000）=252,μ=0.256 mm-1,R 1 =0.0379,wR 2 =0.0919.The specific heat capacity of the title compound was determined by a Micro-DSC method,and the specific heat capacity was 1.25 J·g-1 ·K-1 at 298.15 K.Thermodynamic functions,relative to those at the standard temperature of 298.15 K,were calculated via thermodynamic relationship.The thermal behavior of the title compound under a non-isothermal condition was studied by differential scanning calorimetry/thermogravimetric（DSC/TG） method.There was an obvious endothermic peak in the DSC curve,the peak temperature was 479.43 K.The compound mass loss was 89.94% observed from the TG curve.展开更多
Litterfall, which is influenced by physical and biological factors, is a major pathway for carbon and nutrient cycling in forest ecosystems. The purpose of this study was to investigate monthly litterfall production i...Litterfall, which is influenced by physical and biological factors, is a major pathway for carbon and nutrient cycling in forest ecosystems. The purpose of this study was to investigate monthly litterfall production in three forests in Jeju Island differentiated by forest composition and precipitation: Cheongsu(Quercus glauca as the dominant species;low precipitation), Seonheulb(Q. glauca as the dominant species;high precipitation), and Seonheulm(Q. glauca and Pinus thunbergii as the dominant species;high precipitation). Litterfall was collected monthly from April to December 2015 and divided into leaf litter, twig, bark, seeds, and unidentified materials.Seasonal patterns of litterfall production varied across stands according to their species composition. However,the amount of leaf litterfall and total litterfall were comparable among stands, ranging from 362 to 375 g m-2 for leaf litter and 524 g m-2 to 580 g m-2 for total litterfall.Oak leaf litter in May was the highest in all stands, while needle litter was the highest in December in Seonheulm.High twig litterfall in July may be attributable to high rainfall with strong winds and storms during the rainy season. Although forest type and climate factor had no influence on litterfall amounts in this study, the pattern of litterfall production was species dependent, suggesting diverse effects on carbon and nutrient cycling in these forests.展开更多
基金The financial support of CLP Holdings Limited is acknowledged for supporting KFBG's ongoing applied forest restoration research.
文摘Both abiotic conditions and management influence the success of forest restoration.Despite growing interest and practical effort in restoring degraded forest landscapes,understanding of how disparate factors,such as terrain,soil conditions,climate and silvicultural treatments,directly or collectively control species performance and shape community recovery remains limited.In this study,we assessed how topography and management intervention affect seedling survival and growth in the early stages of restoration.To do so,we established seven experimental plots,each measuring 20 m×20 m(400 m2)subdivided into 48 subplots,in coarse,anthropogenic grassland on a mid-elevation mountain slope in Hong Kong,and planted a total of 3975 native tree seedlings belonging to 12 tree species within them.To characterise topography,we modelled the elevation,slope,convexity and aspect of each subplot.Two types of tree guard(enclosed blue plastic sleeve and open yellow mesh),two types of fertiliser(organic and inorganic)and cardboard weeding mats were used to assess the impact of management interventions on the establishment of the seedlings.Survivorship,height and basal diameter were measured at 1,2 and 4 years after planting.We used generalised linear models to examine the effect of these factors and their interactions on seedling survival,and we applied linear models and hierarchical partitioning to explore their relative importance in determining the relative growth rate(RGR)of each species.The most parsimonious models were selected using the Akaike Information Criterion.Survivorship was 98.1%,95.2%and 86.4%across all plots in the first,second and fourth year,respectively.On average,topographic and management variables explained 1.48–3.34%of total variation in RGR,respectively,for all species.The models revealed that type of tree guard,aspect and elevation were the most important factors explaining RGR and survival.Results of hierarchical partitioning by species and growth period showed that the key determinants of performance vary by species and shift over the course of early seedling establishment,emphasising the importance of both spatial and temporal scales in the restoration of degraded tropical forests.Our findings support the use of enclosed tree guards and fertiliser to improve survivorship and growth across a range of broadleaved Asiatic species.All potential limiting factors pertaining to both site factors and management,as well as their interactions,should be considered in restoration planning to maximise restoration success.
基金in the framework of the Actions A.11 and D.3—LIFE14 IPE IT 018 GESTIRE 2020—Nature Integrated Management to 2020MM is currently a post-doc at the University of Milan,funded by LIFE FALKON LIFE17 NAT/IT/000586
文摘Background: Inland wetlands are crucial for biodiversity conservation, especially in highly-urbanized landscapes. In the European Union, many wetlands are included in the EU ‘Natura 2000’ network, the main tool for biodiversity conservation over the continent, which requires the development of site-specific management plans. Clear and feasible recommendations are necessary to provide site managers with effective tools for the maintenance of biodiversity in these unstable environments. Birds are excellent umbrella species, therefore a management targeted at increasing habitat suitability for focal bird species would likely benefit broader wetland biological communities. Methods: During spring–summer 2017, we collected presence/absence data for 10 bird species of conservation interest at a site scale for 21 Natura 2000 sites. We also carried out a point count survey to detect presence/absence of four reedbed-dwelling species at 75 points. At the site level, we estimated landscape characteristics from regional GISlayers, whereas fine-scaled habitat composition was recorded on the field within a 100 m-buffer around the 75 points. We analysed the effect of the extent of different habitats on species’ occurrence probability by means of multi-species binomial multivariate adaptive regression splines (MARS) at both scales. We also run species-specific MARS models to compare their performance with those of multi-species models. Results: At the site scale, the extent of the reedbeds/mires was positively associated with the occurrence of all species of conservation concern. At the point-count scale, reedbed extent positively predicted species’ occurrence, but only in presence of patches of clear shallow water. Species-specific MARS models showed qualitatively similar results for some species, but generally were outperformed by multi-species ones. Conclusions: Multi-species MARS models confirmed to be an efficient tool in disclosing species-habitat relationships even for set of species including scarce taxa and when only short-term monitoring data are available. In terms of conservation measures, our findings stress the importance of Phragmites australis reedbed as a key habitat for avian biodiversity, but only when it is flooded and interspersed with scattered patches of open water. The preservation of wide (>100/150 ha) and flooded reedbeds structured in spots of no less than 2 ha emerges as the main conservation measure for the long-term conservation of the threatened avifauna of inland pre-Alpine wetlands.
基金the comprehensive ecological baseline survey programme of the Department of Agriculture ,Fisheries and Conservation
文摘We surveyed the distribution, composition and diversity of freshwater fish in Hong Kong, China from 2002 to 2004. Sites surveyed were mainly streams, marshes and estuaries. There are ponds for aquaculture and reservoirs in Hong Kong but no large natural water bodies. From the 220 sites surveyed, 114 species of 37 families were found. Gobiidae (with 24 species) and Cyprinidae (21 species) were the dominant families. This survey has increased the number of freshwater fish species recorded in Hong Kong to 167. Among these, 71 (42.5%) are primary freshwater fish, 44 are brackish and 46 are vagrants. The remaining 6 species are diadromous. In Hong Kong, freshwater fish are conserved by a combination of measures. About 38% of Hong Kong’s land area is designated as country parks and/or special areas, and is managed for nature conservation and educational purposes. In addition, another 5% of land area is zoned for conservation in the statutory land use zoning system to protect them from development and incompatible land uses. Major development projects have to go through the statutory environmental impact assessment process to ensure that they will not have adverse impact as far as practicable. There are conservation action plans for important species. For example, captive-bred individuals of the endemic Hong Kong Paradise Fish Macropodus hongkongensis have been released to suitable and secure sites inside country parks and their populations are regularly monitored. Other measures such as wetland creation, restoration and enhancement programmes are also implemented for freshwater fish conservation.
文摘The Red-footed Falcon(Falco vespertinus)is a species of high international conservation interest.We analyzed its hunting behavior at the two largest colonies in Italy during the nestling period.Using accurate data-loggers,we tracked three adult Red-footed Falcons in June and July,2019 and collected 4703 GPS points.We detected clear patterns of hovering and perching activity(HPA)in both time and space.HPA occupied one-third of the Red-footed Falcons’day,and showed two peaks just after sunrise(between 35 and 40%of the monitoring time)and just before sunset(50‒60%)in both June and July,and minimum(20‒30%)at night and during the hottest time interval(10:00 a.m.‒4:00 p.m.).Almost 40%of HPA occurred within 50 m from nests.Our findings,although preliminary,have important implications for the conservation of these two colonies that are located within two Natura 2000 sites.The detected spatio-temporal patterns of Red-footed Falcons’hunting behavior suggests the creation of two nested protection belts:the inner one is a narrow belt(up to 50 m from the two rows of trees that host the two colonies)with integral conservation,and hopefully increase the alfalfa crops and fallow land,and the outer belt(50 m‒2 km)with optimized agricultural activities.
文摘During this study, the principal aim carried out was to obtain more information about technique and conservation conditions of the Egyptian wall paintings during the Roman period in the funerary house in necropolis of Tuna el-Gabal, El-Minia-Upper Egypt. It’s going back to 2nd century AD and involves different sites of Ptolemaic and Roman chapels;some are in the immaculate established style while others are a blend of Pharaonic-Greek style and both are secured with mural painting. Deterioration problems observed on the wall paintings of the funerary house are, loss of plaster layers, disintegration of plaster layers, loss of paint layers (blistering and peeling), discoloration and severely damaged owing to a lot of deterioration factors as weakness of mud brick support, deterioration of surface treatments and to the widespread presence of different salts. The materials used in the painting, preparation layers and the state of conservation of the mural painting at funerary house were investigated by integrated physio-chemical measurements, particularly micro-Raman spectroscopy (µRaman), light optical microscopy (LOM), scanning electron microscopy (SEM) coupled with an energy dispersive X-ray analysis system (EDX), X-ray powder diffraction (XRD) and Fourier transform infrared (FT-IR). In addition, the morphology of multilayer plaster from wall painting was investigated using atomic force microscopy (AFM). A wide color palette utilized as a part of the necropolis has been identified with mineral pigments and pigment mixtures. It is found that, the paints were based on an organic binder and traditional pigments (azurite, hematite, ochre, vegetable black) were used as colorants on plaster. The examination demonstrated that the preparatory layer is verging on made of pure lime while the plaster layer based mainly of lime and gypsum with variable amounts of quartz. The obtained results provided information about the painting technique, chemical composition, crystal structure in addition to the stratigraphy of the paint layers and the state of preservation and on the causes of the painting deterioration. Furthermore, the obtained results can be used in the conservation and restoration interventions of these sites.
文摘The Roman Period temple of Isis at Shenhur was built and enhanced amid the rule of Augustus (30 BCE-14 CE) through that of Trajan (98-117 CE). It was built of two sorts of local limestone and decorated with reliefs. Examination of conservation state uncovered that it was collapsed and only partly preserved and it disposed of some still buried rooms. The temple is exposed to different deteriorations processes created by internal and external stresses because of the mineral composition of the building materials, atmosphere variables, salts crystallization and groundwater. In this study, the deterioration problems of the wall reliefs were examined for the aim of its conservation. For this purpose, the chemical, physical and structural characterization were performed by means of X-Ray Diffraction (XRD) and observation of thin section by transmitted light optical microscopy (LOM), polarized microscope, Scanning Electron Microscope (SEM) attached with EDX and thermogravimetric (DTA & TGA). Additionally, microbiological study and chemical analyses of ground water were carried out. Results demonstrated that the deterioration of Shenhur was because of the forceful activity of the environment agents and soluble salts such as chlorides and sulphates. These results and information allowed that the identification of the types of salts and deterioration features might be used in the future for conservation purposes.
文摘Helal El-Beah mosque in Egypt was built from many different materials as sandstone, bricks and marble. These building materials were in a bad condition due to many degradation factors, mainly ground water and salt weathering, so many deterioration phenomena were appeared as horizontal and vertical cracks, salts, loss of the Islamic decorations in the fa?ade and mihrab (Prayer niche), detachment of the plaster, biological colonization and featured dark of the stone surface. Prior to the conservation intervention, the building materials were characterized to identify their components. Scientific conservation treatment was carried out for the long-term conservation of the mosque. Conservation operations at the mosque included: repairing and roof insulation, wet and dry cleaning, joining of cracked parts and surface consolidating, replacement of the Portland cement plaster with lime plaster, re-cladding the lower part of the interior brick walls with sandstone tiles, replacement and completion of the stone blocks.
基金Fundamental Research Funds for Central Public Welfare Research Institutes,Grant/Award Number:CKSA2023479/NYNSFC-MWR-CTGC Joint Yangtze River Water Science Research Project,Grant/Award Number:U2040213+1 种基金Basic Scientific Research Business Funding Projects of Central Public Welfare Research Institutes,Grant/Award Numbers:CKSF2019251/NY,CKSF2021299/NYProjects of International Cooperation and Exchanges NSFC,Grant/Award Number:52211540722。
文摘SWAT model is one of the primary tools for assessing irrigation district water management and water-saving measures.However,its incapacity to consider the diverse growth and water requirements of paddy during various growth stages,as well as the insufficient availability of external water sources.This study introduces the Penman-Monteith equation and Jensen model into the SWAT framework,setting crop coefficients,crop base coefficients,and growth stage sensitivity indices based on the different growth stage.Additionally,modifications are made to the external water source available for irrigation and paddyfield leakage modules,establishing a distributed agricultural hydrological model suitable for accurately simulating water balance elements and paddy yield in multi-source irrigation districts.The Yangshudang watershed in the Zhanghe irrigation district is chosen for the evaluation of the modified model's simulation performance,with a quantitative assessment of water-saving and yield-increasing effects.The results demonstrate that the modified model effectively meets the requirements for simulating paddy evapotranspiration of various growth stages,yield,agricultural irrigation water consumptions,and runoff,exhibiting a notable enhancement in performance.As two common water-saving measures in irrigation areas,inter-mittent irrigation and irrigation district renovation were used as two water-saving scenarios in the simulation of the modified SWAT model.Under intermittent irrigation,the watershed experiences a 6.58%reduction in net irrigation water use.In the scenario with irrigation district renovation,the water resources in the watershed are utilized more efficiently.The modified model from this study can be applied for assessing the synergistic effects of irrigation district water-saving and yield-increasing measures,providing crucial insights for the formulation of irri-gation district water-saving strategies and water resource optimization plans.
文摘通过对黑土坡耕地免耕、少耕与传统耕作土壤物理性状全生育期观测，比较研究土壤结构和导水性状季节变化差异及其与水土流失的关系。结果表明，表层0～20 cm土壤，免耕土壤容重全生育期维持在1.20～1.30 g cm^-3，变化小，大于0.25 mm的水稳性团聚体含量（WR0.25）和平均重量直径（MWD）高于传统耕作，初始和稳定入渗速率均高于少耕和传统耕作，土壤含水量分别较少耕和传统耕作高4.7和4.4个百分点，较传统耕作分别减少地表径流和土壤流失量86%和100%；少耕除夏季各项性状均介于免耕和传统耕作之间，夏季垄沟深松后，垄沟土壤容重显著降低，较免耕和传统耕作降低0.15 g cm^-3以上，提高土壤初始入渗速率30%以上，较传统耕作减少水和土壤流失量20%和40%。传统耕作土壤容重，垄台由播种时的0.91 g cm^-3增加至收获时的1.23 g cm^-3，垄沟一直维持在1.30 g cm^-3左右，WR0.25、MWD、土壤稳定入渗速率、含水量均较低，全生育期10%的雨水流失，土壤流失量615 t km^-2 a^-1。免耕土壤结构稳定，蓄水保水最佳，为效果显著的水土保持耕作措施，少耕也有一定的保水保土作用；免耕和少耕均能够改善土壤物理性状。
基金supported by the National Natural Science Foundation of China(Grant Nos.41271303,40901135)the National Key Technology R&D Program(Grant Nos.2012BAK10B04,2008BAD98B02)+2 种基金the Non-profit Industry Financial Program of MWR(Grant No.201301058)the Changjiang River Scientific Research Institute of Sciences Innovation Team Project(Grant No.CKSF2012052/TB)Central public welfare scientific research project(Grant No.CKSF2013013/TB)
文摘Aggregate stability is a very important predictor of soil structure and strength, which influences soil erodibility. Several aggregate stability indices were selected erodibility of four soil properties from temperate for estimating interrill types with contrasting and subtropical regions of China. This study was conducted to investigate how closely the soil interrill erodibility factor in the Water Erosion Prediction Project （WEPP） model relates to soil aggregate stability. The mass fractal dimension （FD）, geometric mean diameter （GMD）, mean weight diameter （MWD）, and aggregate stability index （ASI） of soil aggregates were calculated. A rainfall simulator with a drainable flume （3.0 m long × 1.0 m wide × 0.5 m deep） was used at four slope gradients （5°,10 °,15° and 20°）, and four rainfall intensities （0.6, 1.1, 1.7 and 2.5 mm/min）. Results indicated that the interriU erodibility （Ki） values were significantly correlated to the indices of ASI, MWD, GMD, and FD computed from the aggregate wet-sieve data. The Kihad a strong positive correlation with FD, as well as a strong negative correlation with ASI, GMD, and MWD. Soils with a higher aggregate stability and lower fractal dimension have smaller Ki values. Stable soils were characterized by a high percentage of large aggregates and the erodible soils by a high percentage of smaller aggregates. The correlation coefficients of Ki with ASI and GMD were greater than those with FD and MWD, implying that both the ASI and GMD may be better alternative parameters for empirically predicting the soil Ki factor. ASI and GMD are more reasonable in interrill soil erodibility estimation, compared with Ki calculation in original WEPP model equation. Results demonstrate the validation of soil aggregation characterization as an appropriate indicator of soil susceptibility to erosion in contrasting soil types in China.
基金supported by the Key Projects of National Philosophy and Social Science Foundation of China(11&ZD046)The Key Projects of National Natural Science Foundation of China (70833001)+2 种基金China Agricultural Research System (CARS-14-10B)Doctoral Fund of Ministry of Education of China (20120097110034)the Fundamental Research Funds for the Central Universities of China(6J0546)
文摘According to the contemporary ecosystem approach, the linkages of human actions with their environment have to be assessed in an integrative manner. The Driver-Pressure-State-Impact-Response （DPSIR） model is applied to identify and describe processes and interactions in human-environmental systems. An example application from a research project dealing with the development of sustainable management strategies for the agriculture in Jiangsu, China, illustrates the potentials and limitations of its sustainable development. The concept and indicators of ecological integrity are used to assess the indicators in the dimensions of DPSIR between 2003 and 2006. The main drivers included population growth which caused increasing demand for food, growing environmental demands, and rapidly decreasing of land and other natural resources. The main environmental problem was water pollution. The results show that in the dimension of driver, total grain output and agricultural land productivity both increased. Labor intensive agriculture has been promoted to increase agricultural land productivity. In the dimension of pressure, on the positive side, infrastructure got greatly improved, the input level such as total power of machinery, and level of fertilizer use increased, and level of pesticides use decreased, but on the negative side, cultivated land per capita and irrigation rate decreased, natural resources keep decreased. Environmental pollution indicators such as industrial wastewater discharge and acid rain rate increased in Jiangsu Province. In the aspect of state, ecosystem state was improved, plant coverage index increased, biological abundance index increased, fertilizer productivity increased, eco-environmental quality index increased, but land degradation index also increased. In the aspect of impact, output level increased, output efficiency enhanced, farmer＇s social economic benefit improved. In the aspect of response, social support was greatly improved, input for environmental governance increased. To assess the effects of environmental governance, Jiangsu government was successful to increase compliance rate of sulfur dioxide emissions, but not so efficient in compliance rate of industrial wastewater discharge.
基金funded by the National Natural Science Foundation of China(Grant No.41877082)the Fundamental Research Funds for Central Public Welfare Research Institutes(Grant No.CKSF2019410TB)+2 种基金the National Natural Science Foundation for Young Scientists of China(Grant No.41701316,51909011)the National Key R&D Program of China(Grant No.2017YFC050530302)the Demonstration Project of Water Conservancy Technology(Grant No.SF-201905)。
文摘Biological soil crusts(biocrusts)are important landscape components that exist in various climates and habitats.The roles of biocrusts in numerous soil processes have been predominantly recognized in many dryland regions worldwide.However,little is known about their effects on soil detachment process by overland flow,especially in humid climates.This study quantified the effects of moss-dominated biocrusts on soil detachment capacity(Dc)and soil erosion resistance to flowing water in the Three Gorges Reservoir Area which holds a subtropical humid climate.Potential factors driving soil detachment variation and their influencing mechanism were analyzed and elucidated.We designed five levels of coverage treatments(1%–20%,20%–40%,40%–60%,60%–80%,and 80%–100%)and a nearby bare land as control in a mossdominated site.Undisturbed soil samples were taken and subjected to water flow scouring in a hydraulic flume under six shear stresses ranging from 4.89 to 17.99 Pa.The results indicated that mean Dc of mosscovered soil varied from 0.008 to 0.081 kg m^-2 s^-1,which was 1.9 to 21.0 times lower than that of bare soil(0.160 kg m^-2 s^-1).Rill erodibility(Kr)of mosscovered soil ranged from 0.0095 to 0.0009 s m^-1,which was 2 to 20 times lower than that of bare soil(0.0187 s m^-1).Both relative soil detachment rate and Kr showed an exponential decay with increasing moss coverage,whereas the critical shear stress(τc)for different moss coverage levels did not differ significantly.Moss coverage,soil cohesion,and sand content were key factors affecting Dc,while moss coverage and soil bulk density were key factors affecting Kr.A power function of flow shear stress,soil cohesion,and moss coverage fitted well to estimate Dc(NSE=0.947).Our findings implied that biocrusts prevented soil detachment directly by their physical cover and indirectly by soil properties modification.Biocrusts could be rehabilitated as a promising soil conservation measure during ecological recovery to enhance soil erosion resistance in the Three Gorges Reservoir Area.
文摘Calcium hydroxide （CH） dressing residues can compromise endodontic sealing. This study aimed to evaluate the amount of remaining CH in root canals after mechanical removal by four groups of irrigation techniques including needle irrigation only, ProTaper file, EndoActivator, and ultrasonic file. Fifteen extracted single-rooted teeth were collected and used for all four groups. The samples were firstly prepared by ProTaper rotary instruments, and then sectioned longitudinally through the long axis of the root canals, followed by final reassembling by wires. CH was kept in the canals for 7 days setting. The removal procedure began with 5 mL of 2.5% sodium hypochlorite （NaOC1） followed by 1 mL of 17% ethylenediaminetetraacetic acid and a final irrigation with 5 mL of 2.5% NaOC1 solution for all groups. No additional agitation of the irrigant was performed in group 1, while agitation for 20 s be- tween irrigants was done with F2 ProTaper rotary file in group 2, EndoActivator with tip size 25/.04 in group 3 and by an ultrasonic file 25/.02 in group 4. The total activation time was 60 s. The roots were then disassembled and captured by digital camera. The ratio of CH coated surface area to the surface area of the whole canal as well as each third of the canal was calculated. The data were statistically ana- lyzed by one-way ANOVA using post hoc Tukey test. Results showed that none of the four techniques could remove all CH. No significant difference was found between EndoActivator and ultrasonic tech- niques. However, they both removed significantly more CH than ProTaper and needle irrigation （P=0.0001）. In conclusion, the sonic and ultrasonic agitation techniques were more effective in removing intracanal medicaments than the ProTaper rotary file and needle irrigation in all thirds of the canal.
基金the University Grants Council of Hong Kong and its Area of Excellence Program to PJH. KF was supported by a JSPS grant on the ecophysiology of green Noctiluca in the Gulf of Thailand. PMG received funding from NSF （No. OCE-1015980）This is contribution number 4502 from the University of Maryland Center for Environmental Studies. KY Acknowledges Support from the CAS/SAFEA International Partnership Program for Creative Research Teams （No. KZCXZYW-T001）. DMA received partial funding through the NSF/NIEHS Centers for Oceans and Human Health （No. NIEHS P50 ES012742, NSF OCE- 043072 and OCE-0911031）, and through NSF Grant （No. OCE-0850421）+1 种基金 This paper is based on work partially supported by SCOR/LOICZ Working Group 132, supported by the Scientific Committee on Oceanographic Research （SCOR） through grants from the U.S. National Science Foundation （No OCE-0938349 and OCE-0813697） from the Land-Ocean Interactions in the Coastal Zone （LOICZ） Project and the Chinese Academy of Sciences. We thank A. KANA for assistance with the GIS produced maps and LIU Hao for his assistance with the tables and references.
文摘The dinoflagellate Noctiluca scintillans is one of the most important and abundant red tide organisms and it is distributed world-wide. It occurs in two forms. Red Noctiluca is heterotrophic and fills the role of one of the microzooplankton grazers in the foodweb. In contrast, green Noctiluca contains a photosynthetic symbiont Pedinomonas noctilucae （a prasinophyte）, but it also feeds on other plankton when the food supply is abundant. In this review, we document the global distribution of these two forms and include the first maps of their global distribution. Red Noctiluca occurs widely in the temperate to sub-tropical coastal regions of the world. It occurs over a wide temperature range of about 10℃ to 25℃ and at higher salinities （generally not in estuaries）. It is particularly abundant in high productivity areas such as upwelling or eutrophic areas where diatoms dominate since they are its preferred food source. Green Noctiluca is much more restricted to a temperature range of 25℃-30℃ and mainly occurs in tropical waters of Southeast Asia, Bay of Bengal （east coast of India）, in the eastern, western and northern Arabian Sea, the Red Sea, and recently it has become very abundant in the Gulf of Oman. Red and green Noctiluca do overlap in their distribution in the eastern, northern and western Arabian Sea with a seasonal shift from green Noctiluca in the cooler winter convective mixing, higher productivity season, to red Noctiluca in the more oligotrophic warmer summer season.
基金supported by the National Natural Science Foundation (40901135)973 program (2007CB40720301)+1 种基金National Key Technology R&D Program (2008BAD98B02)the open fund of Institute of Changjiang River Scientific Research program (YWF0716/TB01)
文摘Annual discharge and annual suspended sediment loads of Beipei Hydrological Station of the Jialing River catchment were analyzed to describe the trend of Jialing River over the last five decades (1956-2006). These loads were also analyzed to ascertain the influential factors associated with its variation with the help of Kendall's Tau-b correlation analysis and regression analysis. The results indicated that the Jialing River annual discharge showed no significant trend at >95% confidence level while the annual sediment load appeared to have a significant decrease trend over the last 50 years. A decrease in the annual sediment load was particularly apparent after the year 1985, at which a substantial shift in the sediment level occurred. This shift is attributed to the construction of numerous dams in 1980s. However, after the year of 1985, two periodical stages (1986-1991 and 1992-2006) with distinct sediment load and sediment-runoff ratio were identified. The period 1992-2006 is characterised by low sediment load, which is most probably due to the impact of large scale of soil and water conservation, which took place at the end of the 1980s. Last, models describing the relationship between the discharge and the sediment load, discharge and sediment-runoff ratio as well as between the sediment load and sediment-runoff ratio were constructed.
文摘Since trees and plants can absorb CO2, forests are widely regarded as a carbon sink that may control the amount of CO2 in the atmosphere. The CO2 uptake rate of plants is affected by the plant species and environmental conditions such as photosynthetically active radiation (PAR), temperature, water and nutrient contents. PAR is the most immediate environmental control on photosynthesis while air temperature affects both photorespiration and dark respiration. In the natural condition, PAR and temperature play an important role in net CO2 uptake. The effects of PAR and air temperature on the CO2 uptake of Pterocarpus macrocarpus grown in a natural habitat were studied in the present work. Due to many uncontrollable factors, a simple rectangular hyperbola could not represent the measured data. The data were divided into groups of 2oC intervals; CO2 uptake in each group may then be related to PAR by a rectangular hyperbola function. Using the obtained functions, the effect of PAR was removed from the original data. The PAR-independent CO2 uptake was then related to air temperature. Finally, the effects of PAR (I) and air temperature (Ta) on the CO2 uptake rate (A) were combined as: (-0.0575Ta2+2.6691Ta-23.264)I A= ——————————————— (-0.00766Ta2+0.40666Ta-3.99924) (-4.8794Ta2+227.13Ta-2456.9)+I
基金Supported by Project of Shandong Water Resources Department" Study on the Mechanism and Comprehensive Control Benefit of Soil Erosion in the Typical Eroded Area of Shandong"
文摘[Objective] The aim was to study the main rainfall factors influencing runoff and sediment in the sloping farmland with different plants in the central south of Shandong Province.[Method] Through grey relational analysis,the effects of different rainfall factors on runoff and sediment with different plants in the central south of Shandong were studied.[Result] In the sloping farmland with different plants,the effects of rainfall factors on runoff and sediment weren’t consistent.Rainfall was the dominant influencing factor of runoff,but PI30 had the greatest influence on runoff in natural grassland.Meanwhile,rainfall intensity was the main influencing factor of sediment,but PI had the greatest influence on sediment in Astragalus adsurgens Pall.plot.The compound factor had the minimal influence on runoff and sediment in Arachis hypogaea plot and natural grassland.In A.adsurgens Pall.plot,rainfall intensity had the minimal impact on runoff,but the compound factor had the least effect on sediment.[Conclusion] The study could provide theoretical references for the comprehensive control of slope soil erosion,the optimum utilization and sustainable development of land.
基金Supported by the National Natural Science Foundation of China(No.20571060)the Natural Science Foundation of Shaanxi Province,China(No.2007B08)
文摘N-（2,3-Dimethyl-phenyl）-N＇-（methoxyl formyl）thiourea was synthesized by the reacting of 2,3-dimethylaniline,potassium thiocyanate（KSCN） and methyl chloroformate（ClCOOCH 3）.Single crystal was obtained by slowly evaporation solvent at room temperature.The structure was characterized by elemental analysis,IR and X-ray crystalography.The compound crystallized：a triclinic system with space group Pī,a=0.83440（12） nm,b=0.89113（13） nm,c=0.93015（13） nm,α=76.548（2） o,β=63.906（2） o,γ=82.538（2） o,V=0.60379（15） nm 3,Z=2,D c =1.311 mg/m 3,F（000）=252,μ=0.256 mm-1,R 1 =0.0379,wR 2 =0.0919.The specific heat capacity of the title compound was determined by a Micro-DSC method,and the specific heat capacity was 1.25 J·g-1 ·K-1 at 298.15 K.Thermodynamic functions,relative to those at the standard temperature of 298.15 K,were calculated via thermodynamic relationship.The thermal behavior of the title compound under a non-isothermal condition was studied by differential scanning calorimetry/thermogravimetric（DSC/TG） method.There was an obvious endothermic peak in the DSC curve,the peak temperature was 479.43 K.The compound mass loss was 89.94% observed from the TG curve.
基金supported by Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(2018R1D1A3B07045079)。
文摘Litterfall, which is influenced by physical and biological factors, is a major pathway for carbon and nutrient cycling in forest ecosystems. The purpose of this study was to investigate monthly litterfall production in three forests in Jeju Island differentiated by forest composition and precipitation: Cheongsu(Quercus glauca as the dominant species;low precipitation), Seonheulb(Q. glauca as the dominant species;high precipitation), and Seonheulm(Q. glauca and Pinus thunbergii as the dominant species;high precipitation). Litterfall was collected monthly from April to December 2015 and divided into leaf litter, twig, bark, seeds, and unidentified materials.Seasonal patterns of litterfall production varied across stands according to their species composition. However,the amount of leaf litterfall and total litterfall were comparable among stands, ranging from 362 to 375 g m-2 for leaf litter and 524 g m-2 to 580 g m-2 for total litterfall.Oak leaf litter in May was the highest in all stands, while needle litter was the highest in December in Seonheulm.High twig litterfall in July may be attributable to high rainfall with strong winds and storms during the rainy season. Although forest type and climate factor had no influence on litterfall amounts in this study, the pattern of litterfall production was species dependent, suggesting diverse effects on carbon and nutrient cycling in these forests.
