西辽河流域归一化植被指数与气象因子相关性分析

为了解西辽河流域归一化植被指数(NDVI)的分布规律、变化趋势及对气候变化的响应,利用2000—2018年西辽河流域11个气象站逐日气象资料和MODIS归一化植被指数数据集,通过线性回归和相关分析,探讨了生长季各月NDVI与气象因子的时滞性,以及气象站周围10 km缓冲区内不同植被类型NDVI与气象因子的相关性.结果表...     

摄食水平对中华鳖(Trionyx sinensis)幼鳖生长和能量收支的影响

于2001年10月—2002年3月在深圳职业技术学院海洋生物技术实验室进行摄食-生长实验(实验周期为56天)。实验在水温30℃的条件下进行,设饥饿、1%、2%和饱食4个摄食水平,研究了中华鳖(Trionyxsinensis)幼鳖(296.60—396.09g)的生长和能量收支。结果表明,中华鳖幼鳖的特定生长率随摄食水平的增加,其湿重、干物质、蛋白质和能量的特定生长率均呈二次曲线增加,其中干物质的特定生长率(SGRdr)与摄食率(Rl)的关系式为SGRdr=-0.3621+0.8809Rl-0.1352Rl2(r2=0.896,n=26,P<0.01);除湿重的转化效率外,干物质、蛋白质和能量的转化效率在2%组均达到最大,分别为27.47%、31.48%和25.01%;摄食水平对中华鳖氨氮排泄率和尿素氮排泄率以及氨氮占总氮排泄率的比例均有显著影响(P<0.01),总氮排泄率、氨态氮排泄率和尿素氮排泄率均随摄食水平的增加而升高,从饥饿组到饱食组的变动范围分别是4.71%—38.70%、3.50%—24.64%和1.21%—6.48%,而氨氮占总氮比例的变化规律与上述指的标略有不同,饥饿组的比例略高于1%组,摄食组的比例随摄食水平的增加而增加,该比例的变动范围是71.92%—83.20%,回归分析表明,幼鳖的总氮排泄率[μmol/(g·d)](GN)、氨氮排泄率[μmol/(g·d)](NH3N)及尿素氮排泄率[μmol/(g·d)](UN)与其蛋自质摄入率(%体重     

海带(Laminaria japonica)幼孢子体生长和光合作用的N需求

根据室内和围隔实验中海带幼孢子体在不同硝态氮浓度下的生长情况和光合作用速率(Pmax),分析了幼孢子体的N需求,得到其最大生长率(μm)为0.12d-1,维持生存的最低组织N含量(NQ)为16.8μg/mgDW,以最大生长率生长所必需组织N的临界值(NC)为20.4μg/mgDW,每天以最大速率生长的N需求(Nreq)为2.45μg/mgDWd-1。同时,不同处理组的初始NO3-N浓度越高,海带幼孢子体吸收速率和组织N的累加速率越高,且呈明显的线性相关关系(R2分别为0.8393和0.7793,P<0.05)。现场围隔实验中,叶绿素a含量(R2=0.7907,P<0.05)和组织N含量(R2=0.9147,P<0.01)与Pmax也呈明显的线性相关关系。同时,根据海带幼孢子体N的需求和营养吸收状况,分析认为,海带幼孢子体存在受到N限制的风险,但凭其营养吸收能力有适应N限制的能力。还根据海带的这种生理特征,探讨了大型海藻的养殖对富营养化海水的生态调控。     

饲料中不同蛋白质和脂肪水平对克氏螯虾（Procambarusclarkii）生长性能、体组成和消化酶活性的影响

采用3×3因子方法,进行了饲料中不同蛋白质和脂肪水平对克氏螯虾f均重（7．03±0．05）g]生长性能、体组成和消化酶活性的影响研究。试验设3个蛋白质水平（24％、27％和30％1和3个脂肪水平（4％、7％和10％）,共9组,每组4个重复,每个重复10尾虾,为期8周。结果表明,蛋白质和脂肪水平对成活率无显著影响（P〉0...     

Origin of transverse folds in an extensional growth-fault setting: Evidence from an extensive seismic volume in the western Gulf of Mexico

Growth faults in gravity-driven extensional provinces are dominated by coast-parallel trends, but coast-perpendicular (transverse) trends are far less documented. The Clemente–Tomas fault in the inner Texas shelf has corrugations that are transverse to the fault and that plunge downdip. A large (8500 km²), high-quality, 3D seismic survey allows a uniquely encompassing perspective into hanging-wall deformation above this corrugated fault surface. Synextensional strata in the hanging wall are folded into alternating transverse ridges and synclines, typically spaced 10 km apart. Forward modelling in dip profiles of an extensional fault having three ramps produces ramp basin-rollover pairs that compare with the seismically revealed ridges and synclines. As they translated down the undulose fault plane, ramp basins and rollovers were juxtaposed along strike, forming the hanging-wall ridges and synclines observed offshore Texas. Fault-surface corrugations correlate broadly with footwall structure. We infer that corrugations on the Clemente–Tomas fault formed by evacuation of an allochthonous salt canopy emplaced in the late Eocene to early Oligocene. Early salt evacuation (Oligocene) created an undulose topography that influenced incipient Clemente-Tomas fault segments as they merged to form an inherently undulose fault. Late salt evacuation (early Miocene) further deformed this fault surface.     

砂岩风化晕厚度在广东晚更新世测年中的应用

广东地区河流阶地和冲积扇沉积物中砂岩砾石风化晕随时间增厚。风化晕生长速度呈指数衰减,并拟合于下列公式:T 1485D4.13这里T=时间,以年表示,D=沉积物表部约50块砾石风化晕厚度的加权平均值,以毫米表示。利用风化晕厚度确定出广东地区河流第一和第二级阶地分别为1000—13300年和8600—26500年,肇庆盆地北部山前地带第Ⅰ和第Ⅱ级冲积扇分别为51500年和24400年。同时,在构造地貌变形分析的基础上,估算出本区三条主要北东向断裂带在晚更新世—中全新世的垂直断层作用速度为0.6—1.6毫米/年,中全新世甚或晚更新世晚期以来的活动速度极小     

晶体生长机理

从扩散控制，成核控制，位错控制和综合控制等几个方面阐述了自溶液中生长晶体的晶体生长机理．     

Climate induced temperature effects on growth performance, fecundity and recruitment in marine fish: developing a hypothesis for cause and effect relationships in Atlantic cod (Gadus morhua) and common eelpout (Zoarces viviparus)

Effects of global warming on animal distribution and performance become visible in many marine ecosystems. The present study was designed to develop a concept for a cause and effect understanding with respect to temperature changes and to explain ecological findings based on physiological processes. The concept is based on a wide comparison of invertebrate and fish species with a special focus on recent data obtained in two model species of fish. These fish species are both characterized by northern and southern distribution limits in the North Atlantic: eelpout (Zoarces viviparus), as a typical non-migrating inhabitant of the coastal zone and the cod (Gadus morhua), as a typical inhabitant of the continental shelf with a high importance for fisheries.Mathematical modelling demonstrates a clear significant correlation between climate induced temperature fluctuations and the recruitment of cod stocks. Growth performance in cod is optimal at temperatures close to 10°C, regardless of the population investigated in a latitudinal cline. However, temperature specific growth rates decrease at higher latitudes. Also, fecundity is less in White Sea than in North and Baltic Sea cod or eelpout populations. These findings suggest that a cold-induced shift in energy budget occurs which is unfavorable for growth performance and fecundity. Thermal tolerance limits shift depending on latitude and are characterized by oxygen limitation at both low or high temperatures. Oxygen supply to tissues is optimized at low temperature by a shift in hemoglobin isoforms and oxygen binding properties to lower affinities and higher unloading potential. Protective stimulation of heat shock protein synthesis was not observed.According to a recent model of thermal tolerance the downward shift of tolerance limits during cold adaptation is associated with rising mitochondrial densities and, thus, aerobic capacity and performance in the cold, especially in eurythermal species. At the same time the costs of mitochondrial maintenance reflected by mitochondrial proton leakage should rise leaving a lower energy fraction for growth and reproduction. The preliminary conclusion can be drawn that warming will cause a northern shift of distribution limits for both species with a rise in growth performance and fecundity larger than expected from the Q₁₀ effect in the north and lower growth or even extinction of the species in the south. Such a shift may heavily affect fishing activities in the North Sea.     

棉铃虫种群消长及影响因子

耕作制度的改变,为棉铃虫种群数量上升提供了良好的食物源和生态环境;大面积使用化学农药,不仅削弱了天敌的控害作用,也提高了棉铃虫的抗药性;气候变暖,适宜于棉铃虫数量上升。因此,棉铃虫种群增加,棉花、玉米、小麦、豆类、瓜菜等受害也明显加重。要控制棉铃虫的发生程度,首先要防治棉田外一代幼虫和卵,减少一代种群数量;对二代棉铃虫,宜有选择地使用化学农药和生物农药进行防治,并充分发挥天敌的自然控制力,以减少种群数量;三代、四代棉铃虫主要危害作物繁殖器官,直接影响作物的产量和品质,以物理诱杀和玉米诱集带集中诱杀为主,既可控制其危害,又对其天敌无负面影响;五代棉铃虫虽对当年作物产量影响不大,但其种群数量直接影响下一年一代发生量,因此应及时喷施病毒类等生物性药剂,降低其越冬种群,同时也保护自然天敌安全越冬。     

气象因子对金花梨生长发育的影响

通过试验研究,探讨主要气象因子在唐河县的变化规律和对金花梨生长发育的影响,研究金花梨在遭受灾害性天气影响时,采取相应的技术措施,确保金花梨的高产、稳产。