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101.
Sea cucumber, Apostichopus japonicus is very sensitive to light changes. It is important to study the influence of light on the molecular response of A. japonicus. In this study, RNA-seq provided a general overview of the gene expression profiles of the body walls of A. japonicus exposed to strong light("light"), normal light("control") and fully dark("dark") environment. In the comparisons of "control" vs. "dark", "control" vs. "light" and "dark" vs."light", 1 161, 113 and 1 705 differentially expressed genes(DEGs) were identified following the criteria of|log_2 ratio|≥1 and FDR≤0.001, respectively. Gene ontology analysis showed that "cellular process" and "binding"enriched the most DEGs in the category of "biological process" and "molecular function", while "cell" and "cell part" enriched the most DEGs in the category of "cellular component". And the DEGs were mapped to 214, 41 and229 pathways in the Kyoto Encyclopedia of Genes and Genomes database, and 51, 2 and 57 pathways were significantly enriched, respectively. Light-specific DEGs identified in this study will be important targets for further investigation to establish the biochemical mechanisms involved in the adaption of this sea cucumber to changes in the level of environmental light.  相似文献   
102.
普里兹湾及其邻近海域是中国南大洋调查研究的传统优势海域与重点区域。围绕夏季表层水、冬季水、陆架水、绕极深层水、南极底层水、普里兹湾底层水、冰架水等研究海区主要水团的特征和分布,总结了前人在南极普里兹湾及其邻近海域基于调查资料开展的水团研究中所取得的成果。研究表明,前人在对陆架水的示性指标界定上,将陆架水是否区分为高盐陆架水和低盐陆架水存在较大争议,在高盐陆架水和普里兹湾底层水的定义上存在重叠;目前尚没有证据表明绕极深层水向南可以伸展到普里兹湾的陆架区域,也没有发现在普里兹湾附近海域生成南极底层水的直接证据。  相似文献   
103.
利用浙江省常规气象观测资料、ERA5逐小时再分析资料、FY-4A卫星黑体亮度温度(TBB)资料,对2020年6月3日、6月30日两次暴雨过程进行对比分析。结果表明:(1)6月3日暴雨过程(简称“6·03”过程)发生在季风槽背景下,浙江省500 hPa处于槽前西南气流中,850 hPa为暖切变;而6月30日过程(简称“6.30”过程)发生在东北冷涡背景下,浙江省500 hPa处于冷暖气流交汇中,850 hPa为冷切变。两次过程降水落区相似,均集中在浙西地区,呈东西向带状分布,但“6·30”过程暴雨区范围更广,暴雨中心雨量和过程雨量更大,小时雨强更强,强降水持续时间更长。(2)两次过程均为对流不稳定性降水,但强降水落区发生在急流的不同位置。“6·03”过程为暖切变型暖区暴雨,对流云团“列车效应”显著,降水落区位于急流前方水汽通量强辐合区内,而“6·30”过程梅雨锋为西风辐合型锋生,对流云团为后向传播路径,降水落区位于急流轴附近的水汽通量强辐合区内。700 hPa水汽通量辐合大值区及强度与未来6 h强降水落区、强度相对应,这在梅汛期暴雨预报中有一定参考性。(3)降水类型不同,对应锋生作用不同...  相似文献   
104.
Biotite‐rich selvedges developed between mafic schollen and semipelitic diatexite in migmatites at Lac Kénogami in the Grenville Province of Quebec. Mineral equilibria modelling indicates that partial melting occurred in the mid‐crust (4.8–5.8 kbar) in the range 820–850°C. The field relations, petrography, mineral chemistry and whole‐rock composition of selvedges along with their adjacent mafic schollen and host migmatites are documented for the first time. The selvedges measured in the field are relatively uniform in width (~1 cm wide) irrespective of the shape or size of their mafic scholle. In thin section, the petrographic boundary between mafic scholle and selvedge is defined by the appearance of biotite and the boundary between selvedge and diatexite by the change in microstructure for biotite, garnet, plagioclase and quartz. Three subtypes of selvedges are identified according to mineral assemblage and microstructure. Subtype I have orthopyroxene but of different microstructure and Mg# to orthopyroxene in the mafic scholle; subtype II contain garnet with many mineral inclusions, especially of ilmenite, in contrast to garnet in the diatexite host which has few inclusions; subtype III lack orthopyroxene or garnet, but has abundant apatite. Profiles showing the change in plagioclase composition from the mafic schollen across the selvedge and into the diatexite show that each subtype of selvedge has a characteristic pattern. Four types of biotite are identified in the selvedges and host diatexite based on their microstructural characteristics. (a) Residual biotite forms small rounded red‐brown grains, mostly as inclusions in peritectic cordierite and garnet in diatexite; (b) selvedge biotite forms tabular subhedral grains with high respect ratio; (c) diatexite biotite forms tabular subhedral grains common in the matrix of the diatexite; and (d) retrograde biotite that partially replaces peritectic cordierite and garnet in the diatexite. The four groups of biotite are also discriminated by their major element (EMPA) and trace elements (LA‐Q‐ICP‐MS) compositions. Residual biotite is high in TiO2 and low in Sc and S, whereas retrograde biotite has high Al2O3, but low Sc and Cr. Selvedge and diatexite biotite are generally very similar, but selvedge biotite has higher Sc and S contents. Whole‐rock compositional profiles across the selvedges constructed from micro‐XRF and LA‐Q‐ICP‐MS analyses show: (a) Al2O3, FeO, MgO and CaO all decrease from mafic scholle across the selvedge and into the diatexite; (b) Na2O is lowest in the mafic scholle, rises through the selvedge and reaches its maximum about 20–30 mm into the diatexite host; (c) K2O is lowest in the mafic scholle and reaches its highest value in the first half of the selvedge, then declines before reaching a higher, but intermediate value, about 20 mm into the diatexite. Of the trace elements, Cs and Rb show distributions very similar to K2O.  相似文献   
105.
通过内蒙古大青山地区麻粒岩相岩石内韧性剪切带中流体演化研究,以及与该区内金矿床中流体包裹体的对比,认为产于太古宙高级变质区内的金矿床成因类型复杂,其中有的成矿流体是退变质热液演化的产物,该类矿床可称为退变质热液型金矿床。  相似文献   
106.
陈国民  张喜平  白莉娜  万日金 《气象》2018,44(4):582-589
以中国气象局上海台风研究所整编的最佳路径数据集为依据,对2016年西北太平洋和南海热带气旋(TC)定位精度及路径、强度和登陆点预报精度进行了评定,结果表明:2016年定位总平均误差24.9 km,比2015年略偏大。主观和客观路径预报误差没有延续之前持续减小的趋势,整体预报能力比前两年略有降低。ECMWF EPS、NCEP GEFS和UKMO EPS三个集合预报系统的台风路径预报整体性能要好于其他集合预报系统。各主客观预报方法的台风强度预报性能与往年相比没有大的改进。主观方法对超强台风莎莉嘉在海南万宁的24 h登陆点预报误差均非常小,误差在15 km以下。全球模式的登陆点预报性能表现要优于区域模式。  相似文献   
107.
After the bursting of Huiten Nor in Hoh Xil Region in September, 2011, the topic on whether the water overflowed from the Salt Lake would enter into the Chumaer River and become the northernmost source of the Yangtze River has aroused wide concern from public and academic field. Based on Landsat TM/ETM+/OLI remote sensing images during 2010–2015, SRTM 1 arc-second data, Google Earth elevation data and the observation data from the Wudaoliang meteorological station, the study initially analyzed the variations of the Salt Lake and its overflowing condition and probability. The results showed that the area of the Salt Lake expanded sharply from October 2011 to April 2013, and then it stepped into a stable expansion period. On October 27, 2015, the area of the Salt Lake had arrived at 151.38 km2, which was about 3.35 times the area of the lake on March 3, 2010. The Salt Lake will overflow when its area reaches the range from 218.90 km2 to 220.63 km2. Due to the differences between SRTM DEM and Google Earth elevation data, the water level of the Salt Lake simulated would be 12 m or 9.6 m higher than the current level when the lake overflowed, and its reservoir capacity would increase by 23.71 km3 or 17.27 km3, respectively. Meanwhile, the overflowed water of the Salt Lake would run into the Qingshui River basin from its eastern part. Although the Salt Lake does not overflow in the coming decade, with watershed expansion of the Salt Lake and the projected precipitation increase in Hoh Xil region, the probability of water overflow from the Salt Lake and becoming a tributary of the Yangtze River will exist in the long term.  相似文献   
108.
Bao  Sude  Meng  Junmin  Sun  Lina  Liu  Yongxin 《中国海洋湖沼学报》2020,38(1):55-63
Ocean internal waves appear as irregular bright and dark stripes on synthetic aperture radar(SAR) remote sensing images. Ocean internal waves detection in SAR images consequently constituted a difficult and popular research topic. In this paper, ocean internal waves are detected in SAR images by employing the faster regions with convolutional neural network features(Faster R-CNN) framework; for this purpose, 888 internal wave samples are utilized to train the convolutional network and identify internal waves. The experimental results demonstrate a 94.78% recognition rate for internal waves, and the average detection speed is 0.22 s/image. In addition, the detection results of internal wave samples under dif ferent conditions are analyzed. This paper lays a foundation for detecting ocean internal waves using convolutional neural networks.  相似文献   
109.
Based on high-resolution analysis to a 280-cm long sediment core obtained from the muddy area in the central Yellow Sea, we examined the provenance of muddy sediments and discussed the changing marine sedimentary environment since the middle Holocene. The results indicated that fine-grained sediments in the muddy area were mainly derived from the Huanghe(Yellow River) and Changjiang(Yangtze River) with considerable stepwise variations during the past 6.6 kyr. The Yellow Sea Warm Current was initiated at 6 kyr when the sea level was high together with the enhanced East Asian Winter Monsoon. These in combination established the framework of shelf circulation in the Yellow Sea that began to trap the river-derived fine-grained sediments. From 4.9 kyr to 2.8 kyr, both the Kushiro Current and East Asian Monsoon were significantly weakened, reducing the delivery of Changjiang sediments to the muddy area. As a result, the sediments were mainly originated from the Huanghe. From 2.8 kyr to 1.5 kyr the continuously weakened East Asian Winter Monsoon and enhanced Yellow Sea Warm Current entrapped more fine-grain sediments. Whereas the enhanced East Asian Winter Monsoon and the human caused increase in sediment load of the Huanghe since 1.5 kyr, and direct delivery of Huanghe sediments to the Yellow Sea during 1128–1855 AD might dominated the sedimentation in the study area. The stepwise variations of the sediment provenance and composition of the Central Yellow Sea muddy sediments are of importance to understanding the formation of muddy deposit in the central Yellow Sea and the associated variations of marine environment since the middle Holocene.  相似文献   
110.
基于凸集投影的高分四号卫星影像超分辨率重建   总被引:1,自引:0,他引:1  
许丽娜  何鲁晓 《测绘学报》2017,46(8):1026-1033
基于凸集投影(projection on convex sets,POCS)对GF-4数据进行超分辨率重建处理。利用能量连续降减法构造参考帧以减少迭代次数,提高算法效率;利用Vandewalle配准法对图像块进行运动估计从而获取精确的运动参数有利于图像的分块处理。通过对GF-4真实数据进行试验与分析,表明超分图像结果的清晰度与序列影像帧数呈正相关;信噪比与帧数呈负相关。应用5帧数据进行超分重建,清晰度(平均梯度)从7.803提高到14.386;信噪比会略有下降,从3.411下降到3.336。试验表明该方法可以有效提高图像清晰度,增加图像细节信息,提升图像判别能力,扩展数据的应用范围。  相似文献   
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