Does wetland watershed land use influence amphibian larval development? A relevant effect of agriculture on biota

Agriculture practices have been widely proposed as the major cause of amphibian population decline. However, the majority of these results have been based on laboratory experiments. The present study was conducted to test the repercussion of wetland sediment provenance on amphibian larval development.Bufo bufo larvae were used in two dif ferent treatments in an outdoor experiment, the ?rst one using sediment from one wetland surrounded by intensive agricultural practices, and the second using sediment with no record of agrochemical uses. A negative ef fect was observed in the agricultural treatment, from subcellular to individual level. The results showed that the sediment from agricultural practices watershed generates a reduction in survival. Furthermore, individuals that developed under this treatment showed a lower total length and a delay in the time necessary to complete metamorphosis; these features are connected with recruitment success. In the same way, biochemical analysis showed high values of lipid peroxidation in metamorphs developing in sediments from an agricultural area. Finally, the results obtained highlight the importance of considering the sediments, not only the water, as origin treatment, allowing us to understand the consequences on amphibian populations that inhabit areas af fected by intensive agriculture.     

塔里木河下游生态输水条件下胡杨林生态系统恢复研究

基于文献阅读,对塔里木河下游生态输水条件下胡杨林生态系统的恢复响应进行了讨论分析.生态输水显著抬升了地下水位,降低了地下水矿化度与土壤干旱指数,有效改善了塔里木河下游胡杨林生态系统的生境;胡杨复壮明显,距河道50 m胡杨冠幅最大增长达511.20％,距河道500 m内胡杨枯枝比平均小于0.15.输水后,下游胡杨树干径向...     

Background and Research Prospect of Geo-ecological Survey and Monitor in the Critical Zone of Black Soil

正The American Science journal,on the occasion of its 125 publication anniversary,in 2016,released 125 of the most challenging scientific issues (Kennedy et al.,2005) to the world.According to the basics,breadth and the influence,25 of the issues which considered to be the most important were screened,including"How many people can the Earth carry?"(Stokstad,2005;Dailyg et al.,1992;Cohen,1995) and"How high will the greenhouse effect make the earth temperature?"These two     

Development of periglacial landforms and soil formation in the Ilgaz Mountains and effect of climate(Western Black Sea Region-Türkiye)

The main aims of the current study are to determine the morphological features of the periglacial landforms(non-sorted step, mud circle, stony earth circle, thufur, and congeliturbation) located on the Ilgaz Mountains, examine the physicochemical and mineralogical properties with pedological processes of the soils, and assess of the effects of climatic conditions controlling the development of landforms. The Ilgaz Mountains(2587 m a.s.l.), located in the Western Black Sea Region, within the Anat...     

基于CTA影像数据全主动脉教学模型3D打印制备研究

目的:通过全主动脉CTA影像学数据实现教学模型的3D打印。方法:本课题拟利用高端CT扫描装置进行数据采集,优化扫描条件,从而生成符合3D打印要求的影像,并将数据进行图像处理与数据转化。结果:将3D影像进行图像处理与数据转化后利用3D打印机进行全主动脉教学模型制备。结论:全主动脉教学模型的3D打印制备可以完善教学模型质量与数量,从而提高教学效果。      

Direct use of peak ground motion parameters for the estimation of inelastic displacement ratio of SDOF systems subjected to repeated far fault ground motions

This study is aimed at developing statistical equations to estimate the inelastic displacement ratio of singledegree- of-freedom systems subjected to far fault repeated earthquakes. In the study, peak ground motion parameters are used to define the scatter of the original data. The ratio of peak ground acceleration to peak ground velocity, and peak ground velocity of the ground motion records and structural parameters such as period of vibration and lateral strength ratio are used in the proposed equations. For the development of the equations, nonlinear time history analyses of single-degree-offreedom systems are conducted. Then, the results are used in a multivariate regression procedure. The equations are verified by comparing the estimated results with the calculated results. The average error and coefficient of variation of the proposed equations are presented. The analyses results revealed that the direct use of peak ground motion parameters for the estimation of inelastic displacement ratio significantly reduced the scatter in the original data and yielded accurate results. From the comparative results it is also observed that results obtained using equations specific to peak ground velocity or peak ground acceleration to peak ground velocity ratio are similar.     

长江水下三角洲沉积物磁性特征空间差异及其冲淤指示意义

三角洲冲淤具有空间异质性,而沉积物的磁性特征可灵敏地反映物源、沉积动力特征以及早期成岩作用影响,是揭示空间异质性的有效方法。选取长江水下三角洲20~35 m水深的四个约2 m长的柱样进行磁学和碳、硫地球化学分析,结合粒度及年代资料,探讨了长江水下三角洲沉积物柱样磁性特征空间差异及其冲淤指示意义。研究结果显示,粒度表征的动力分选影响沉积物的磁性特征,这在年代较新（<350 a）的柱样中表现尤为明显,即细颗粒沉积物中富集亚铁磁性矿物,从而具有较高的磁化率。铁、碳、硫及硫同位素特征揭示了长江水下三角洲沉积物较弱的硫酸盐还原特征。沉积物年龄及沉积速率影响沉积物成岩改造强度,进而导致了磁性特征垂向变化的空间差异,整体上看,远离现代沉积中心的柱样,成岩改造特征更为明显。磁化率值的大小、成岩分带的完整性及其反映的铁还原带和硫酸盐还原带转换深度,一定程度上可以揭示三角洲的淤积和侵蚀特征。     

Research and Application of In‐seam Seismic Survey Technology for Disaster‐causing Potential Geology Anomalous Body in Coal Seam

In order to effectively detect potential geology anomalous bodies in coal bearing formation, such as coal seam thickness variation, small faults, goafs and collapse columns, and provide scientific guidance for safe and efficient mining, the SUMMIT-II EX explosion-proof seismic slot wave instrument, produced by German DMT Company, was used to detect the underground channel wave with the help of transmission method, reflection method and transflective method. Region area detection experiment in mining face had been carried out thanks to the advantage of channel wave, such as its great dispersion, abundant geology information, strong anti-interference ability and long-distance detecting. The experimental results showed that: (1) Coal seam thickness variation in extremely unstable coal seam has been quantitatively interpreted with an accuracy of more than 80% generally; (2) The faults, goafs and collapse columns could be detected and predicted accurately; (3) Experimental detection of gas enrichment areas, stress concentration regions and water inrush risk zone has been collated; (4) A research system of disaster-causing geology anomalous body detection by in-seam seismic survey has been built, valuable and innovative achievements have been got. Series of innovation obtained for the first time in this study indicated that it was more effective to detect disaster-causing potential geology anomalies by in-seam seismic survey than by ground seismic survey. It had significant scientific value and application prospect under complex coal seam conditions.     

A combined IR and XRD study of natural well crystalline goethites(α-FeOOH)

Goethite(a-FeOOH) is one of the most abundant minerals on the Earth surface, occurring in temperate,tropical and equatorial climates. Fe in goethite can be substituted by many cations such as Al, Ni for instance. A large amount of research has been conducted on the effect of varying elemental compositions(mainly Al-content) on the spectral features of goethites with most of the studies based on materials synthesized with different elemental ratios. The different elemental ratios, however, may no...     

A Late Cretaceous ensimatic arc developed during closure of the northern branch of Neo-Tethys(central-northern Turkey)

Studies on differentiation of ensimatic arc units from melange units in the Northern Anatolian Ophiolitic Belt(NAOB) are very rare. The study area represents the southern edge of the central part of the NAOB.The aim of the study is to distinguish the main units of NAOB and to define the geotectonic setting of the Darmik Ensimatic Arc Association(DEAA). To study the ensimatic arc units as an independent tectonic unit is important and facilitates understanding of the geological evolution of the NAOB. During field studies, the contact relationships within the Darmik Ensimatic Arc Association(DEAA) units and also with other tectonic units were reviewed. Then, paleontological, geochronological, petrological and also geochemical properties of the DEAA have been defined. In the present study, ensimatic arc units have been distinguished from ophiolitic association for the first time, in the region. As a result of the study, the DEAA is divided into two levels and lower level named as the Kartal unit and upper level named as the izibüyük unit. In the Kartal unit, basaltic and andesitic lavas with their equivalent pyroclastic rock units are dominant. Radiolarite and mudstones interbedded within the Kartal unit of DEAA have Turonian and Santonian age. In addition, the age of basalt samples of DEAA are 98.7 ± 2.4 Ma, defined using the~(40)Ar/39 Ar method. The izibüyük unit of DEAA comprises conglomerate, sandstone, claystone, mudstone,clayey limestone, micritic limestone with volcanic interbeds and also calciturbidites. Santonian-Maastrichtian ages were obtained from this unit of the DEAA. In conclusion, the age of DEAA is widely accepted as Late Cretaceous. After the evaluation of the analysis, the volcanics of the DEAA originated from calcalkaline-basalts, which reflect ensimatic arc magmatism.