南海红树林内生真菌1356~#代谢产物的研究

从南海红树林内生真菌1356#分离出两种鞘胺醇(A,B)和三种环二肽(C,D,E)?它们的结构通过IR,MS,1D NMR和2D NMR谱推导出来?(3＇E,4E)-1-(-D-吡喃葡萄糖基-3-羟基-2-(2＇-羟基十八碳酰基)氨基-10-甲基-3＇,4,9-十八碳三烯(A)是一种新的鞘胺醇甙?     

Sperm nuclear expansion and meiotic maturation in normal and gynogenetic eggs of the scallop, <Emphasis Type="Italic">Chlamys farreri</Emphasis>

Sperm nuclear expansion, meiosis and the association of the male and female pronuclei leading to the four-cell stage in normal Chlamysfarreri eggs were observed under a fluorescence microscope. The effects of ultraviolet （UV） irradiation on the fertilizing sperm were also examined. Both normal and UV-irradiated sperm nuclei enlarged at three distinct phases （phase A, metaphase I; phase B, polar body formation; and phase C, female pronuclear development and expansion） that were temporally correlated with meiotic process of the maternal chromosomes. Sperm nuclei underwent a rapid, initial enlargement during phase A, but condensed slightly during phase B, then re-enlarged during phase C. The effects of UV irradiation were not apparent during transformation of the sperm nucleus into a male pronucleus, and there was not any apparent effect on meiotic maturation and development of the female pronucleus. However, the rate of expansion of the UV-irradiated sperm nuclei and the size of male pronuclei were reduced apparently. Unlike the female pronucleus, the male pronucleus derived from sperm genome inactivated by UV irradiation did not form chromosomes, but became a dense chromatin body （DCB）. At mitotic anaphase, DCB did not participate in the karyokinesis of the first cleavage as evidenced by chromosomal nondisjunction, demonstrating the effectiveness of using UV irradiation to induce gynogenetic scallop embryos.     

基于人工神经网络的三峡库区丰都县水库塌岸预测

为了建立一个适合于三峡库区的塌岸预测方法体系,采用具有处理非线性关系功能的人工神经网络方法对水库塌岸问题进行研究。通过训练、学习和仿真,获得预测正确率为97.2%的具有7-32-14网络结构的BP神经网络模型,采用该模型对蓄水位为175　m时丰都县各岸段进行塌岸预测,并将预测结果与传统经验公式计算法所得结果及实际监测数据进行对比。结果表明:基于人工神经网络的塌岸预测宽度与实际监测数据很接近,偏差在5 m以内;公式法计算结果与监测值平均偏差为15.9 m,而且对于部分坡段,公式法计算结果比实际监测值小8～11 m,没能预测出塌岸的真正范围。采用神经网络模型对丰都县水库进行塌岸预测,预测结果与实际监测数据平均偏差约3.8%,表明其预测结果可靠。     

大磷虾性比、怀卵量与某些生殖特点的分析

对1985年在南极半岛西北海域各拖网点获得的3852尾大磷虾标本,进行了性别、体长、体重、性成熟度和即将排卵的雌性成体怀卵量的测定。结果得出雌性个体占61.9％,雄性占38.1％;雄性比例在体长51-55毫米个体组中降为20.7％,大于55毫米个体组中仅占8.3％。雌性怀卵量在2457到10799个之间。同一虾群内已排卵的雌性成体比未排卵成体的体重小约1/3。乔治王岛东北海域的虾群在考察时(1月22日)已完成交配,并有2.3％的雌体已经排卵,大部分雌体到2月下旬才会排卵。布兰斯菲尔德海峡的大磷虾性成熟度较低。     

Effect of temperature and photoperiod on maturation of Cephalothrix hongkongiensis （Nemertea： Palaeonemertea）

The limited knowledge about the relationships between environmental factors and the maturation and reproductive seasonality of nemerteans is mostly obtained from field studies, and in many cases is conjectural. Few species have been studied under well-controlled laboratory conditions. In this work, the effects of temperature and photoperiod on gonad development and spawning of Cephalothrix hongkongiensis were observed by rearing worms under different temperatures and photoperiods. Worms reared at 4℃ and 6℃ showed no growth or gonadal development, and all died within 109 days. At 8℃ and 12℃, gonads could be seen from 90 days to the termination of the 360-day experiment, but no spawning was observed. Worms maintained at 16, 24, and 28℃ showed both gonadal development and spawning, and matured faster at higher temperatures. Under a fixed temperature(16℃), photoperiod did not have any significant impact on maturation and spawning. It is likely that temperature plays a major role in regulating the maturation and reproductive cycle of C. hongkongiensis.     

廉州湾红树蚬的繁殖生物学研究

2011年8月至2012年7月,采集广西北海廉州湾红树蚬(Polymesoda erosa)的周年样品进行了性腺发育、生殖周期和胚胎发育研究。结果表明,红树蚬雌雄异体,性别可通过成熟生殖腺颜色区分;1年1个生殖周期,性腺发育可分为增殖期、生长期、成熟期、排放期和休止期5个阶段,性腺发育两性同步;繁殖期从6月延续到11月,其中7月和10月为繁殖高峰期;肥满度指数最高为5.19%(5月份),最低为1.98%(2月份);繁殖方式为非孵育型,沉性卵,外被一层厚的胶质卵膜,水温26℃时,D形幼虫孵出时间约为27h。     

圆弧破坏边坡反演设计的ANN方法与ANFIS方法的比较研究

圆弧破坏边坡反演设计方法,是根据边坡的岩土力学参数及边坡高度,在确保安全系数满足要求的前提下,对圆弧破坏边坡的边坡角进行设计的一种新方法。建立圆弧破坏边坡反演设计方法的关键,就是要对大量稳定圆弧破坏边坡实例加以集成,以建立从{ , c, , H, F}到 的映射。文中收集了大量稳定圆弧破坏边坡实例,采用ANN和ANFIS对其进行了集成,分别建立了圆弧破坏边坡反演设计的ANN方法和ANFIS方法,进而又采用圆弧破坏边坡实例对两者的反演结果进行了比较。结果表明,ANFIS更适合于用来建立圆弧破坏边坡反演设计方法。     

書報述評

主要氣象要素,對於一般昆蟲之活動,究有若何之影響乎?本文特對此有趣味之問題,分為温度,濕度,降水,光及輻射,雲量,風,氣壓及大氣帶電情況等八項討論之,文中數噱,雖僅限某數種昆蟲,然吾人固可由此區區者,而窺得此問題之全豹也。(一)温度(1)温度與昆蟲遷移之關係。因温度之改變,蝗蟲幼蟲遂有成羣遷移之現象,為温度影響昆蟲浩動最佳之證明,惟開始遷移之温度,則因種類不同,而各有異。1921及1924年Cook以三個半月之時間用65誘導陷穽捕捉Nocturnal Lepidoptera,分拆各種氣象要素之影響,     

水文恢复与河蟹养殖对盐碱化沼泽芦苇种群有性生殖特征的影响

芦苇(Phragmites australis)是松嫩平原西部盐碱化沼泽植物群落的优势物种,恢复和扩大芦苇种群有利于松嫩平原西部生态脆弱区的保护和修复。与利用根状茎恢复方法相比,采集芦苇种子破坏性小、更易获取,但芦苇有性生殖能力弱,种子成熟率低。于2021年10月12日,在中国科学院东北地理与农业生态研究所松嫩平原西部盐碱湿地生态研究站的退化区、水文恢复区和养殖河蟹区,收割芦苇样品,测定芦苇的生长指标和有性生殖指标,分析水文恢复和河蟹养殖对芦苇有性生殖特征的影响。研究结果表明,河蟹养殖区和水文恢复区芦苇种群株高、穗长、抽穗数、抽穗率、单穗总花数和结实数的平均值都显著大于退化区(p<0.05),河蟹养殖区的芦苇种群株高和抽穗率的平均值显著大于水文恢复区(p<0.05);河蟹养殖区的芦苇种群密度平均值显著小于退化区(p<0.05);退化区芦苇种群穗的全碳和全氮含量平均值都显著小于水文恢复区和养殖河蟹区(p<0.05),碳氮比平均值显著大于水文恢复区和河蟹养殖区(p<0.05),退化区、水文恢复区和河蟹养殖区内芦苇种群茎叶的全碳、全氮含量以及碳氮比差异都不显著(...