Age, growth, mortality, and radiometric age validation of gray snapper (Lutjanus griseus) from Louisiana

The gray snapper (Lutjanus griseus) is a temperate and tropical reef fish that is found along the Gulf of Mexico and Atlantic coasts of the southeastern United States. The recreational fishery for gray snapper has developed rapidly in south Louisiana with the advent of harvest and seasonal restrictions on the established red snapper (L. campechanus) fishery. We examined the age and growth of gray snapper in Louisiana with the use of cross-sectioned sagittae. A total of 833 specimens, (441 males, 387 females, and 5 of unknown sex) were opportunistically sampled from the recreational fishery from August 1998 to August 2002. Males ranged in size from 222 to 732 mm total length (TL) and from 280 g to 5700 g total weight (TW) and females ranged from 254 to 756 mm TL and from 340 g to 5800 g TW. Both edge analysis and bomb radiocarbon analyses were used to validate otolith-based age estimates. Ages were estimated for 718 individuals; both males and females ranged from 1 to 28 years. The von Bertalanffy growth models derived from TL at age were Lt = 655.4{1–e[–0.23(t)]} for males, Lt = 657.3{1–e[– 0.21(t)]} for females, and L t = 656.4{1–e[– 0.22 (t)]} for all specimens of known sex. Catch curves were used to produce a total mortality (Z) estimate of 0.17. Estimates of M calculated with various methods ranged from 0.15 to 0.50; however we felt that M= 0.15 was the most appropriate estimate based on our estimate of Z. Full recruitment to the gray snapper recreational fishery began at age 4, was completed by age 8, and there was no discernible peak in the catch curve dome.

Efficient sampling of atomic configurational spaces.

We describe a method to explore the configurational phase space of chemical systems. It is based on the nested sampling algorithm recently proposed by Skilling (AIP Conf. Proc. 2004, 395; J. Bayesian Anal. 2006, 1, 833) and allows us to explore the entire potential energy surface (PES) efficiently in an unbiased way. The algorithm has two parameters which directly control the trade-off between the resolution with which the space is explored and the computational cost. We demonstrate the use of nested sampling on Lennard-Jones (LJ) clusters. Nested sampling provides a straightforward approximation for the partition function; thus, evaluating expectation values of arbitrary smooth operators at arbitrary temperatures becomes a simple postprocessing step. Access to absolute free energies allows us to determine the temperature-density phase diagram for LJ cluster stability. Even for relatively small clusters, the efficiency gain over parallel tempering in calculating the heat capacity is an order of magnitude or more. Furthermore, by analyzing the topology of the resulting samples, we are able to visualize the PES in a new and illuminating way. We identify a discretely valued order parameter with basins and suprabasins of the PES, allowing a straightforward and unambiguous definition of macroscopic states of an atomistic system and the evaluation of the associated free energies.

Ca 2+对叶绿体膜流动性及光系统II叶绿素蛋白质复合物的影响

通过实验我们证明Ca2+对叶绿体膜的流动性，对PS I和PS II叶绿素蛋白质复合物的相对含量，以及PS I和PS II的多肽均有影响。 Ca2+对叶绿体膜表层的流动性影响不大，但降低了叶绿体膜深层脂质分子的流动性。从另一个角度阐明了Ca2+抑制光能从PS II向PS I传递的机制。 Ca2+可使PS I的21，23，110KD的多肽转移至PS II，LHCP1和LHCP2中的CF1的两个亚基（55，60KD）转至CPa和LHCP3，从而增加了PS II的捕光截面，引起激发能在两个系统之间的分配的改变。 用免疫学方法可以证明CPIa2和LHCP2的Ab为复合抗体，CPIa1的Ab为单抗，我们可以推测向日葵的不同叶绿素蛋白质复合物具有同源性。

渤海湾海岸带表层沉积物中黑炭和多环芳烃的分布特征

黑碳（BC）是生物质和化石燃料不完全燃烧产生的高度聚合的碳质混合物，包括木炭 （char/charcoal）和烟炱碳（soot）等形式。黑碳产生后大部分储存在燃烧原地，而烟炱碳 由于粒径较小，易进入大气，滞留一到数周后回到地表。部分土壤黑碳随河流和大气的搬 运作用进入海洋环境，主要汇集在海岸带沉积物中。由于黑碳涉及到气候变化、碳循环、 环境危害、人体健康等诸多问题而成为当前气候与环境领域的研究热点。黑碳在环境介质 中比较稳定，因而可以较好的指示人类能源使用及其对环境质量的影响；同时黑碳具有很 强的吸附性，能显著影响周围介质中持久性有机污染物(如多环芳烃等)的赋存状态和生态 毒理效应。 多环芳烃（PAHs）是指两个或两个以上的苯环以稠环形式结合的芳香族化合物，主要 来源于含碳物质的不完全燃烧过程，在环境中广泛存在。由于PAHs 具有潜在的致癌性、 致畸性和致突变性（“三致”效应）而在环境研究领域中备受关注。另外由于具有主体的 同源性，PAHs 可以指示BC 的来源和环境过程。 海岸带沉积物是包括BC 和PAHs 在内的众多污染物在环境地球化学迁移过程中的主 要载体和归宿，由于受到陆地和海洋双重作用，海岸带对环境污染物尤其敏感。环渤海地 区是我国北方的社会经济中心，工业、农业和交通发达、人口稠密，污染严重。前人的研 究表明渤海湾的BC 和PAHs 污染程度明显高于我国其他海岸带，但受限制于采样区域和 样品数量，不能全面地反应BC 和PAHs 在渤海湾海岸带的分布状况及人类活动对海岸带 环境质量的影响。 本次研究在渤海湾海岸带潮间带、近海及主要入海河流系统布设了多条采样剖面，采 集表层沉积物样品85 个。首先，对国际上较为常用的化学热氧化法（CTO-375）处理沉积 物黑碳样品的方法进行了比对实验和优化，然后对全部样品进行黑碳分析；利用GC-MS 方法对样品中的PAHs（USEPA 的16 种优控物）进行了定量检测；对全部沉积物样品还进 行了粒度分析。 结果表明，该区域内黑碳的含量为0.09 到22.8 mg/g dw，其中，潮间带样品的BC 平 均含量为0.52 ± 0.39 mg/g dw，近海样品为0.84 ± 0.38 mg/g dw，河流样品（海河样品除外） 为1.88 ± 0.89 mg/g dw。BC占总有机碳的比例在潮间带、近海、河流区域分别为18.4 ± 8.3%、 14.5 ± 5.3%、14.2 ± 4.1%。潮间带黑碳存在明显的“北高南低”的趋势（以天津港码头和 海河为界），与近海和河流样品的BC 浓度有相似的变化趋势，反映了BC 在海岸带的运移 扩散具有一定的继承性；河流输入可能是近岸沉积物BC 的主要来源。同时，潮间带沉积 物粒度分析结果表明“北区细”(以粘土质粉砂主)而“南区粗”(以砂为主)，反映了两个区 域不同的水动力条件和沉积环境，可能是造成BC 浓度空间分异的主要原因。 摘要 II 多环芳烃的含量分布为33.1-7658.7 ng/g dw，其中，潮间带样品的PAHs 平均含量为 147.0 ng/g dw，近海样品为170.9 ng/g dw，河流样品（海河样品除外）为1228.5 ng/g dw。 主要成分均为三环和四环多环芳烃。PAHs 也呈现出了与BC 相似的“北高南低”的趋势， 多环芳烃与黑碳的相关性研究表明两者相关性较好（R2=0.59），表明多环芳烃和黑碳的同 源性和继承性。运用比值法（菲/蒽，荧蒽/芘，低环/高环等）对多环芳烃的来源解析显示， 整个研究区域内多环芳烃主要为燃烧源。

大功率高稳定度直流稳流软开关电源

本实用新型涉及一种大功率高稳定度直流稳流软开关电源，该电源包括软开关变换单元及其开关管驱动单元、传感器、高精度放大器单元、移相控制单元；该电源充分吸收了现有软开关电源技术的优点，但在现有的软开关电源的基础上合理地设置电容、电感的位置，并将软开关电路的输出信号采用原边并联、副边串联的变压器作电源输出放大器；另还在放大器控制单元采用放大器相频特性和电流传感器干扰信号的补偿技术和移相控制器的动态性能的补偿技术，使软开关电源技术与大功率、高稳定度稳流稳压技术有机地结合在一起。

Impacts of fish sanctuaries on the production and diversity of plankton on beels of haor region in Bangladesh

The experiment was carried out to study the impacts of fish sanctuaries on the production and diversity of plankton in beels of haor region at Mithamain Upazila of Kishoreganj district in Bangladesh during July 2004 to June 2005. A total of 75 (60 phyto and 15 zooplankton) and 74 (59 phyto and 15 zooplankton) genera of plankton were recorded in T-1 and T-2 (with sanctuary) respectively while only 50 (39 phyto and 11 zooplankton) genera were obtained in T-3 (control). Chlorophyceae and Copepoda were the most dominant group of phytoplankton and zooplankton respectively in all the treatments. The total phytoplankton numbers were found to range from 5472 to 35,833 cells/l and 5250 to 40,472 cells/l and total zooplankton from 667 to 1722 cells/l and 611 to 1667 cells/l in T-1 and T-2 respectively in sanctuary sites whereas the ranges of phytoplankton and zooplankton in the control site were 1778 to 29,333 cells/l and 56 to 1056 cells/l respectively. The maximum phytoplankton and zooplankton were recorded during winter season in all the treatments. The ranges of total plankton were 6194 to 37,500 cells/l, 6028 to 41,806 cells/l and 1889 to 29,444 cells/l in T-1, T-2 and T-3 respectively. The phytoplankton, zooplankton and total plankton recorded in treatments with sanctuary were significantly higher (p<0.5) than the treatment without sanctuary (control) indicating positive impacts of sanctuaries on the production of plankton. Between two treatments of fish sanctuaries the total plankton populations were comparatively higher in T-2 than T-1.

Effects of Abnormal Early Rearing Environments on Fear Memory in Adult Rats

为了探讨早期饲养环境对成年后大鼠条件化恐惧的影响,实验采用巴氏恐惧条件化的方法对不同饲养环境下的大鼠进行了行为检测.具体操作为:把断奶后的大鼠饲养在3个不同的人工控制的环境中(丰富环境、社群环境和贫瘠环境);8周后进行恐惧条件化训练和测试(指标为僵直百分比),以及检测不同饲养环境下的大鼠的体重、自发活动和足部电击敏感性.结果显示:与社群组相比,丰富组的大鼠条件化僵直水平明显增加,而贫瘠组的明显减少;丰富和贫瘠环境明显的影响了大鼠的体重;不同环境对自发活动和足部电击敏感性没有影响.这些结果说明幼年期的丰富环境能提高成年后大鼠的由声音诱发的条件化恐惧反应,而贫瘠环境则削弱了这种反应.