Developing an intermediate-complexity projection model for China's fisheries: A case study of small yellow croaker(Larimichthys polyactis) in the Haizhou Bay,China

Projection models are commonly used to evaluate the impacts of fishing. However, previously developed projection tools were not suitable for China's fisheries as they are either overly complex and data-demanding or too simple to reflect the realistic management measures. Herein, an intermediate-complexity projection model was developed that could adequately describe fish population dynamics and account for management measures including mesh size limits, summer closure, and spatial closure. A two-patch operating model was outlined for the projection model and applied to the heavily depleted but commercially important small yellow croaker(Larimichthys polyactis) fishery in the Haizhou Bay, China, as a case study. The model was calibrated to realistically capture the fisheries dynamics with hindcasting. Three simulation scenarios featuring different fishing intensities based on status quo and maximum sustainable yield(MSY) were proposed and evaluated with projections. Stochastic projections were additionally performed to investigate the influence of uncertainty associated with recruitment strengths and the implementation of control targets. It was found that fishing at FMSY level could effectively rebuild the depleted stock biomass, while the stock collapsed rapidly in the status quo scenario. Uncertainty in recruitment and implementation could result in variabilities in management effects; but they did not much alter the management effects of the FMSY scenario. These results indicate that the lack of science-based control targets in fishing mortality or catch limits has hindered the achievement of sustainable fisheries in China. Overall, the presented work highlights that the developed projection model can promote the understanding of the possible consequences of fishing under uncertainty and is applicable to other fisheries in China.     

Post-depositional modification of NO-3 in snow layers at EastAntarctica and at the headwater of ürumqi River

Acidic species, such as Nitrate, in polar snow and firn layers are “reversibly” deposited, and are sufficiently volatile to undergo significant postdepositional exchange between snow/firn and the atmosphere. Through comparison of the snowpit and snowpack nitrate concentrations from central East Antarctica and the headwater of ürumqi River, we conclude that the nitrate peaks in the uppermost surface snow layers in central Antarctica are not related to an atmospheric signal and must account for post-depositional effects. Such effects, however, are not found in the surface snowpack nitrate profiles from the headwater of ürumqi River. Two reasons may account for the post-depositional difference. At first, nitrate in the polar snow and firn layers appears to be hydrated ion, which can be taken up by the atmosphere, while at the headwater of ürumqi River it seems mainly as mineral ion, which assembles the behavior of aerosol-derived species that are “irreversibly” deposited and do not undergo significant post-depositional exchange with the atmosphere. Secondly, the chemical features of the snow and ice on the Antarctica are mainly determined by wet deposition, to the contrary, dry deposition is more significant at the headwater of lUrumqi River than that on the East Antarctic Plateau.     

公用机房的硬盘保护措施

在深入分析硬盘结构及硬盘工作原理的基础上,详细阐述了用软件实现对公用机房硬盘的保护原理和方法,并给出了编程思路。     

我国北方区域沙尘天气的时间特征分析

将我国北方沙尘主要影响区划分为3个区（西北区、华北区、东北区）,用网格面积加权计算区域平均的方法,比较了各区沙尘天气的时间演化特征。结果表明：西北部沙尘日数的量级明显多于东北部;沙尘暴的发生有比较明显的日变化特征,各区白天较夜间更易发生沙尘暴,2区（华北区）和3区（东北区）发生沙尘暴初始时刻的峰值出现在14：00,1区（西北区）出现在15：00～16：00;2区和3区出现沙尘天气的极值在4月,而1区在4、5两个月都是极值期;春季是各区沙尘天气的多发期,1区夏季沙尘天气发生的频次也较高;各区的沙尘日数均在20世纪80年代中期前后发生了由多到少的跃变,1区和2区的突变点在1987年,3区在1983年。我国北方3个区沙尘天气的日、月、季节变化有明显的区域特征,其中1区表现得较为独特,2区和3区则比较接近。     

2000～2004年天津市大气污染特征分析

根据天津市2000～2004年的环境监测资料和同期气象资料,对天津市大气污染物浓度变化的时空变化特征、大气污染与天气条件的关系进行了研究。结果表明:天津市大气污染物具有明显的时空分布规律,时间上表现为冬强夏弱,年际之间SO2和PM10浓度减轻,NO2变化不大。空间上表现为SO2和PM10在中心城区改善明显,NO2浓度在局部地区仍在增加。天气形势、城市热岛、逆温和混合层高度等对污染物浓度影响很大。     

辽宁晚侏罗世里阿斯箭蜓科－新属（昆虫纲，蜻蜓目）

本文描述了我国辽宁省北票市上侏罗统义县组中的里阿斯箭蜒科（Ｌｉａｓｓｏｇｏｍｐｈｉｄａｅ）一新属（Ｃｈｒｙｊｏｇｏｍｐｈｕｓｇｅｎ．ｎｏｖ．）。这是里阿斯箭蜒科昆虫化石在我国的首次发现,对研究这个类群的起源、演化和地理分布都具有重要意义．     

云南个旧大白岩铜锡矿床铜锡与共伴生组分赋存状态研究

位于个旧市南部的卡房矿田大白岩铜锡矿是个旧地区重要的铜矿产出地段,共伴生锡、金、银、钨、铋等有益组分。通过光薄片鉴定、电子探针测试和人工重砂分析发现,大白岩铜锡矿铜主要赋存状态为黄铜矿,其次为银黝铜矿和黝锡矿;锡主要以锡石,黝锡矿形式存在;伴生组分钨主要为白钨矿,铋元素以辉铋矿和自然铋存在,硫主要为磁黄铁矿、黄铁矿,其次为黄铜矿等硫化物,磁黄铁矿和黄铜矿中含有微量金。     

Heavy metals pollution on the sediments in lakes Dianchi, Erhai and Poyanghu and historical records

In this paper²¹⁰ Pb and ¹³⁷Cs dating methods were used to determine sedimentation rates of lakes Dianchi, Erhai and Poyanghu, and to establish the time scale of the sediments. Also based on geochemical records in the sediment column, the historical variation in heavy metal content over the past one hundred years was determined. Some element concentration increased rapidly after the 1970s, such as Cu, Zn and Mn in the sediments of northern Lake Dianchi, Cd and Mn in southern Lake Erhai and in the west central parts of Lake Poyanghu, Our investigations indicate that the increase in element concentration is caused by human activities. In order to understand the extent of the effect caused by human activities, we have calculated the flux of Zn, Cd and Mn. Results show that the flux caused by human activities is seven times greater than the natural one and the ratio is about 2 times in Lake Erhai and Lake Poyanghu.     

Magmatic Evolution and Mineralization of Porphyry Copper-Gold Deposits in the Duolong Ore Concentration Area, Tibet

<正>The Bangong Lake-Nujiang River metallogenic belt is located between the Qiangtang Block and Lhasa Block,and the Duolong ore concentration area is located in the western section of the Bangong Lake-Nujiang River metallogenic belt.Till now,several large and super large copper-gold deposits,such as Duobuza,Bolong,     

石笋氧同位素和微量元素记录的陕南地区4200～2000a B.P.高分辨率季风降雨变化

基于陕南祥龙洞石笋XL2的19个230Th年龄、218个氧同位素分析以及896个Sr/Ca分析数据,高分辨率重建了4200～1972a B.P.期间陕南地区季风降雨变化.重建结果显示陕南地区这一时期季风降雨有显著的127～105a和57a周期,可能分别受控于太阳活动、PDO和/或AMO的变化.重建时段有3次百年尺度的干旱事件,分别发生于2200～2100a B.P.,2900～2700a B.P.和3600～3400a B.P.,其中2900～2700a B.P.干旱事件对应于北大西洋地区2.8ka冷事件.对比研究显示,尽管祥龙洞石笋和董哥洞石笋δ18O记录整体一致,但除了2900～ 2700aB.P.干旱事件之外,其他两次干旱事件在董哥洞石笋记录中并不明显.而尽管总体上祥龙洞和和尚洞石笋δ18O记录的差异要大,但XL2的3次干旱事件在和尚洞记录都有明显体现.有精确年代控制的祥龙洞、董哥洞及和尚洞石笋氧同位素记录的差异,揭示晚全新世我国季风降雨在十一百年尺度存在区域差异.