雌牙鲆CYP19A基因启动子“CpG”岛区的单核苷酸多态性及与繁殖性能的关联分析     

何峰  马瑞芹  赵旭  张宇  于锦涛  温海深  李吉方 《中国海洋大学学报(自然科学版)》2011,41(9):19-24

芳香化酶基因(CYP19)编码的芳香化酶是雄激素转化为雌激素的关键酶,在鱼类性腺发育及繁殖内分泌过程中起着重要的作用。本研究采用聚合酶链式反应-单链构象多态(PCR-SSCP)和放射性免疫方法(RAI)对61尾雌牙鲆进行了CYP19A基因启动子CpG岛区多态性检测,并将其与繁殖性能进行了关联分析。CpG岛区存在3种类型的基因型(pattern1、pattern2、pattern3),经测序发现CpG岛区有以下突变:T-1927插入或缺失、C-1899插入或缺失、T-1772C、C-1766T、TGTCAAC-1752~-1744插入或缺失(11个SNPs连锁突变)。方差分析结果表明:此位点对雌二醇(E2)水平的效应达到显著(P<0.05)水平,经多重比较分析,具有pattern1基因型的个体的雌激素(E2)水平显著低于pattern2和pattern3基因型个体的雌激素水平(P<0.05),同时pattern1基因型的个体的mRNA表达量显著低于pattern2和pattern3基因型个体的mRNA表达量(P<0.05)。以上结果表明,CYP19A基因调控区甲基化位点突变可能导致芳香化酶的表达量,进而影响牙鲆繁殖内分泌过程;同时也阐明了这些与牙鲆繁殖性状相关的SNPs可以用于生产实践中进行标记辅助选择具有优良繁殖性能的牙鲆。  相似文献   

COVID-19疫情防控中的中国公众舆情时空演变特征   总被引：1，自引：0，他引：1  

王卷乐  张敏  韩雪华  王晓洁  郑莉 《地理学报》2020,75(11):2490-2504

COVID-19疫情是全球面临的重大公共卫生危机。客观认识疫情期间的公众舆情响应和区域差异,对于提高重大公共卫生事件的政策调控和科学治理具有现实意义。本文以新浪微博为数据源,基于潜在狄利克雷分配主题模型和随机森林算法构建了主题抽取和分类模型,识别微博文本中的13个舆情话题,并从数量、空间、时间、内容等方面分析了2020年1月9日—3月10日在湖北省、京津冀、长三角、珠三角、成渝等城市群及沿边口岸等重点区域分布特点。结果表明：中国公众的响应总体是理性和积极的,但各舆情话题在区域内部的空间分布差异明显。各区域热点分布中,京津冀以首都北京为中心,长三角以上海为中心,辅以南京、杭州等热点,珠三角以广州、深圳为两核,湖北省以武汉为中心。建议应持续加强重点区域的疫情舆情关注和因地制宜的差异化精准响应。  相似文献   

The outgassing and composition of Comet 19P/Borrelly from radio observations     

Dominique Bockelée-Morvan  Nicolas Biver  Pierre Colom  Florence Henry  John K. Davies  Harold A. Weaver 《Icarus》2004,167(1):113-128

Radio spectroscopic observations of Comet 19P/Borrelly were performed during the 1994 apparition and at, and near, the time of the Deep Space 1 flyby in 2001. HCN, CS, CH₃OH, and H₂CO were detected using the 30-m telescope of the Institut de Radioastronomie Millimétrique and the James Clerk Maxwell Telescope, and their production rates relative to water are estimated to be 0.06-0.11, 0.07, 1.7, and 0.4%, respectively. Only upper limits are derived for H₂S and CO. The upper limit for CO/H₂O (<15%) is not very constraining, while the upper limit for the H₂S/H₂O ratio of 0.45% is near the bottom of the range of values measured for other comets. Observations of the OH radical at the Nançay radio telescope provide water production rates a few weeks before the 1994 and 2001 perihelia. Observations of the 1₁₀-1₀₁ water line at 557 GHz with the Odin satellite yield a water production rate of (2.5±0.5)×10²⁸ s⁻¹ on September 22, 2001, at the time of the Deep Space 1 encounter, and (3.3±0.6)×10²⁸ s⁻¹ averaged over the September 22-24, 2001 period. The line shapes are asymmetric and blueshifted by V₀∼−0.18 km s⁻¹ for the best observed HCN lines recorded one week after perihelion. The HCN line shapes, and the similar OH and HCN velocity shifts over the September-November 1994 and August-September 2001 periods, favor anisotropic outgassing towards the Sun. Strong outgassing directed along the primary dust jet seen on visible images is not excluded by the HCN line shapes, but unrealistically high gas expansion velocities are required to explain the line shapes in that case.  相似文献   

Deep Space 1 photometry of the nucleus of Comet 19P/Borrelly     

B.J Buratti  M.D Hicks  D Britt  J.K Hillier 《Icarus》2004,167(1):16-29

The NASA-JPL Deep Space 1 Mission (DS1) encountered the short-period Jupiter-family Comet 19P/Borrelly on September 22, 2001, about 8 days after perihelion. DS1's payload contained a remote-sensing package called MICAS (Miniature Integrated Camera Spectrometer) that included a 1024 square CCD and a near IR spectrometer with ∼12 nm resolution. Prior to its closest approach of 2171 km, the remote-sensing package on the spacecraft obtained 25 CCD images of the comet and 45 near-IR spectra (L. Soderblom et al., 2002, Science 296, 1087-1091). These images provided the first close-up view of a comet's nucleus sufficiently unobscured to perform quantitative photometric studies. At closest approach, corresponding to a resolution of 47 meters per pixel, the intensity of the coma was less than 1% of that of the nucleus. An unprecedented range of high solar phase angles (52-89 degrees), viewing geometries that are in general attainable only when a comet is active, enabled the first quantitative and disk resolved modeling of surface photometric physical parameters, including the single particle phase function and macroscopic roughness. The disk-integrated geometric albedo of Borrelly's nucleus is 0.029±0.006, comparable to the dark hemisphere of Iapetus, the lowest albedo C-type asteroids, and the uranian rings. The Bond albedo, 0.009±0.002, is lower than that of any Solar System object measured. Such a low value may enhance the heating of the nucleus and sublimation of volatiles, which in turn causes the albedo to decrease even further. A map of normal reflectance of Borrelly shows variations far greater than those seen on asteroids. The two main terrain types, smooth and mottled, exhibit mean normal reflectances of 0.03 and 0.022. The physical photometric parameters of Borrelly's nucleus are typical of other small dark bodies, particularly asteroids, except preliminary modeling results indicate its regolith may be substantially fluffier. The nucleus exhibits significant variations in macroscopic roughness, with the oldest, darkest terrain being slightly smoother. This result suggests the infilling of low-lying areas with dust and particles that have not been able to leave the comet. The surface of the comet is backscattering, but there are significant variations in the single particle phase function. One region exhibits a flat particle phase function between solar phase angles of 50° and 75° (like cometary dust and unlike planetary surfaces), suggesting that its regolith is controlled by native dust rather than by meteoritic bombardment.  相似文献   

Short-wavelength infrared (1.3-2.6 μm) observations of the nucleus of Comet 19P/Borrelly     

L.A Soderblom  D.T Britt  B.J Buratti  T.C Owen 《Icarus》2004,167(1):100-112

During the last two minutes before closest approach of Deep Space 1 to Comet 19P/Borrelly, a long exposure was made with the short-wavelength infrared (SWIR) imaging spectrometer. The observation yielded 46 spectra covering 1.3-2.6 μm; the footprint of each spectrum was ∼160 m × width of the nucleus. Borrelly's highly variegated and extremely dark 8-km-long nucleus exhibits a strong red slope in its short-wavelength infrared reflection spectrum. This slope is equivalent to J-K and H-K colors of ∼0.82 and ∼0.43, respectively. Between 2.3-2.6 μm thermal emission is clearly detectable in most of the spectra. These data show the nucleus surface to be hot and dry; no trace of H₂O ice was detected. The surface temperature ranged continuously across the nucleus from ?300 K near the terminator to a maximum of ∼340 K, the expected sub-solar equilibrium temperature for a slowly rotating body. A single absorption band at ∼2.39 μm is quite evident in all of the spectra and resembles features seen in nitrogen-bearing organic molecules that are reasonable candidates for compositional components of cometary nuclei. However as of yet the source of this band is unknown.  相似文献   

Visible Lightcurve Observations of Comet 19p/Borrelly     

Mueller  Béatrice E. A.  Samarasinha  Nalin H. 《Earth, Moon, and Planets》2002,90(1-4):463-471

The final Deep Space 1 (DS1) mission target, comet 19P/Borrelly, was observedfrom July 28–August 1, 2000 at the CTIO-1.5 m telescope in the R filter. Theobserved lightcurve has a large peak to peak variation between 0.84 mag and1.0 mag. A period of 26.0 ± 1 hr (assuming a double-peaked lightcurve)was found using all five nights. This is in good agreement with the period of25.02 ± 0.5 hr quoted by Lamy et al. (1998) using only 6 points ofHST data and is also consistent with HST data taken around the DS1 encountertime by Weaver et al. (2002).Using the mean magnitude R = 20.8 mag and assuming a 4% albedo, we derivean effective nuclear radius of 2.6 km. The large lightcurve amplitude translates toa long to intermediate axial ratio a/b ≥ 2.2, in excellent agreement with theHST result of a/b ≥ 2.4 (Lamy et al., 1998) and with DS1 images (Soderblom et al., 2002).  相似文献   

COVID-19 to go? The role of disasters and evacuation in the COVID-19 pandemic     

《Global Environmental Change》2022

Since the start of the pandemic, some U.S. communities have faced record storms, fires, and floods. Communities have confronted the increased challenge of curbing the spread of COVID-19 amid evacuation orders and short-term displacement that result from hazards. This raises the question of whether disasters, evacuations, and displacements have resulted in above-average infection rates during the COVID-19 pandemic. This study investigates the relationship between disaster intensity, sheltering-in-place, evacuation-related mobility, and contagion following Hurricane Zeta in Southeastern Louisiana and The Wildfires in Napa and Sonoma Counties, California, known as the Glass Fire. We draw on data from the county subdivision level and mapped and aggregated tallies of Facebook user movement from the Facebook Data for Good program’s GeoInsights Portal. We test the effects of disasters, evacuation, and shelter-in-place behaviors on COVID-19 spread using panel data models, matched panel models, and synthetic control experiments. Our findings suggest associations between disaster intensity and higher rates of COVID-19 cases. We also find that while sheltering-in-place led to decreases in the spread of COVID-19, evacuation-related mobility did not result in our hypothesized surge of cases immediately after the disasters. The findings from this study aim to inform policymakers and scholars about how to better respond to disasters during multi-crisis events, such as offering hotel accommodations to evacuees instead of mass shelters and updating intake and accommodation procedures at shelters, such as administration temperature screenings, offering hand sanitizing stations, and providing isolated areas for ill evacuees.  相似文献   

疫情背景下中国居民城际出行恢复力、恢复模式与影响因素     

勾艺超  魏铭  王姣娥  王成金 《地球信息科学学报》2022,24(10):1941-1956

新冠疫情爆发以来,居民城际出行受到显著影响,其时空波动规律反映了居民城际出行恢复力和恢复模式。文章基于百度迁徙数据,着眼于疫情防控常态化阶段,分析城际出行恢复力的分异格局,归纳总结时序波动规律与模式,并构建计量模型探究影响城际出行恢复力的因素。研究构建了波动比率、恢复比率、恢复弹性和恢复指数4个指标,用以衡量城际出行恢复力大小;将2021年中国新冠疫情划分为4个波次,各轮疫情持续时长不一,涉及地区范围各异。研究发现：① 居民城际出行恢复力表现出一定的空间差异,东部地区最好,西部地区和中部地区其次,东北地区最差;② 居民城际出行恢复模式时序与传统韧性三角形模式相似,根据疫情传播特征和性质具体可归纳为相对独立型、中间波动型、起点关联型、终点关联型、双向受制型等5种模式,表现出各异的曲线形态和特征;③ 对于居民城际出行恢复力的影响因素,机场、高铁等交通因素具有正向相关关系,而与GDP、产业结构等经济因素的影响表现为U型关系。疫情防控背景下,城际出行恢复模式和恢复力是城市韧性的重要方面,为制定相关城市政策提供了科学依据。  相似文献   

新冠肺炎疫情背景下日本应急避难场所运营管理新动向     

金英淑 《中国地震》2022,38(2):322-337

通过梳理日本防控传统传染病视角下的应急避难场所运营管理方法,对比分析新冠肺炎疫情下日本应急避难场所运营管理面临的困境,总结出新冠肺炎疫情下日本应急避难场所运营管理新动向,以及日本政府针对新冠肺炎疫情下应急避难场所运营管理实施的具体措施,如应急避难场所的布局与防止感染对策、日常运营管理对策等,以期为我国新冠肺炎疫情常态化防控下应急避难场所的运维提供借鉴。  相似文献   

后疫情时代中国铜资源供应形势分析     

韩见  夏鹏  邢佳韵  朱清  武海炜  潘志君  王芳 《地球学报》2021,42(2):223-228

中国是全球最大的铜消费国,每年消耗全球近一半的铜资源.但国内铜矿资源紧缺,产量相对有限,2019年对外依存度高达78％.本文主要从中国铜资源供需形势、进口来源地风险分析、铜资源公司综合竞争力、新冠肺炎疫情对中国铜资源供应影响等方面系统地分析了后疫情时代中国铜资源供应形势,并给出了如下建议:一是加大国内铜资源的勘查力度,增加资金投入,力争保障国内关键产业铜资源的自给;二是加强多边国际合作,降低铜资源的进口集中度;三是给予在海外投资的中资企业相应的政策和金融支持,积极扩大海外冶炼产能,打通非洲铜资源上下游产业链.  相似文献