Age and growth estimates of the winter skate (Leucoraja ocellata) in the western Gulf of Maine

Age and growth estimates for the winter skate (Leucoraja ocellata) were estimated from vertebral band counts on 209 fish ranging in size from 145 to 940 mm total length (TL). An index of average percent error (IAPE) of 5.8% suggests that our aging method represents a precise approach to the age assessment of L. ocellata. Marginal increments were significantly different between months (Kruskal-Wallis P<0.001) and a distinct trend of increasing monthly increment growth began in July. Estimates of von Bertalanffy growth parameters suggest that females attain a slightly larger asymptotic TL (L∞=1374 mm) than males (L∞=1218 mm) and grow more slowly (k=0.059 and 0.074, respectively). The oldest ages obtained for the winter skate were 19 years for males and 18 years for females, which corresponded to total lengths of 932 mm and 940 mm, respectively. The results indicate that the winter skate exhibits the characteristics that have made other elasmobranch populations highly susceptible to exploitation by commercial fisheries.

云南保种乳用圭山羊遗传多样性蛋白电泳研究

采用水平式淀粉胶蛋白电泳技术,对路南保种乳用圭山羊33个个体的46个遗传座位的血液蛋白及同工酶的多态性进行了研究。结果发现AKP、LAP、CES-I、ESD、ME和Pa6个座位具多态性,多态座位的基因AKP~(0)、LAP~(A)、CES-I~(1)、ME~(B)、ESD~(1)和Pa~(A)的基因频率较高;多态座位百分比P=0.1304,平均杂合度H=0.0501。在Tf座位,出现两种表型AA、AB,但多态性贫乏;LDH谱带中发现一种不同的类型。

一种改进的阴茎电刺激采精法和猕猴藏酋猴及熊猴的采精及其精液特征的初步研究

本文报道了一种改进的阴茎电刺激采精法，用脱脂棉和铝箔作为电极，以避免直接用金属电极可能对阴茎的损伤，并运用这一方法对猕猴（Ｍａｃａｃａｍｕｌａｔｔａ）、藏酋猴（Ｍ．ｔｈｉｂｅｔａｎａ）和熊猴（Ｍ．ａｓｓａｍｅｎｓｉｓ）进行了电刺激采精及其精液特征研究。电刺激采精模式为连续刺激和间断刺激方式。在采精过程中没有发生阴茎损伤。对初次接受电刺激采精的动物以间断刺激模式效果较好。猕猴、藏酋猴和熊猴的射精体积分别为２．０±０．１、６．３±１．１和３．２±０．６ｍｌ；液化体积分别为０．７±０．６、２．１±０．４和１．７±０．３ｍｌ；精子浓度分别为１２．６±１．２×１０~８、４５．６±５．６×１０~８和１１．５±０．９×１０~８／ｍｌ。３种动物精液的液化率分别为：猕猴３６．２±０．９％，藏酋猴３４．０±１．４％；熊猴５１．８±１．２％。３种动物的精子总数与射精体积和凝块体积没有相关性（ｒ~２＝０．０７９；０．０１６；０．０９４和ｒ~２＝０．０６４；０．０２０；０．０７２）。上述结果表明：１）改进的阴茎电刺激采精法适用于猕猴，特别是阴茎表面较为粗糙的藏酋猴和熊猴；２）藏酋猴的射精体积和精子总数是迄今已报道的非人灵长类中最大的，...

Uncertainty management for on-line optimisation of a POMDP-based large-scale spoken dialogue system

The optimization of dialogue policies using reinforcement learning (RL) is now an accepted part of the state of the art in spoken dialogue systems (SDS). Yet, it is still the case that the commonly used training algorithms for SDS require a large number of dialogues and hence most systems still rely on artificial data generated by a user simulator. Optimization is therefore performed off-line before releasing the system to real users. Gaussian Processes (GP) for RL have recently been applied to dialogue systems. One advantage of GP is that they compute an explicit measure of uncertainty in the value function estimates computed during learning. In this paper, a class of novel learning strategies is described which use uncertainty to control exploration on-line. Comparisons between several exploration schemes show that significant improvements to learning speed can be obtained and that rapid and safe online optimisation is possible, even on a complex task. Copyright © 2011 ISCA.

三峡水库蓄水前后水生态系统动态的初步研究

本专辑登录的论文系中国科学院知识创新工程重要方向性项目“三峡水库库区蓄水前后水生态系统变化的研究”的部分研究结果,内容包括1)蓄水前后水体理化参数变化;2)蓄水前后水生生物群落变化;3)三峡水库的富营养化问题;4)春季水华暴发过程的连续监测与动力学;5)对三峡水库生态学研究的几点思考和建议。

五种淡水吸管虫原生动物中国新纪录种的描述

对采自于中国洞庭湖和汉阳墨水湖氧化沟的5种吸管虫做了形态学报道,均为国内新纪录:靴状盘吸管虫Discophryacothurnata(Weisse,1847-1848)Lachmann,1859;粗壮盘吸管虫DiscophryarobustaNozawa,1938;长柄球吸管虫Metacinetamacrocaulis(Stokes,1887)Matthes,1954;圆形放射吸管虫Heliophryarotunda(Hentschel,1916)Matthes,1954和孟加拉锤吸管虫Tokophrya

Elemental unbiased estimators for the Generalized Pareto tail

Unbiased location- and scale-invariant `elemental' estimators for the GPD tail parameter are constructed. Each involves three log-spacings. The estimators are unbiased for finite sample sizes, even as small as N=3. It is shown that the elementals form a complete basis for unbiased location- and scale-invariant estimators constructed from linear combinations of log-spacings. Preliminary numerical evidence is presented which suggests that elemental combinations can be constructed which are consistent estimators of the tail parameter for samples drawn from the pure GPD family.

Elemental estimators for the Generalized Extreme Value tail

In a companion paper (McRobie(2013) arxiv:1304.3918), a simple set of `elemental' estimators was presented for the Generalized Pareto tail parameter. Each elemental estimator: involves only three log-spacings; is absolutely unbiased for all values of the tail parameter; is location- and scale-invariant; and is valid for all sample sizes $N$, even as small as $N= 3$. It was suggested that linear combinations of such elementals could then be used to construct efficient unbiased estimators. In this paper, the analogous mathematical approach is taken to the Generalised Extreme Value (GEV) distribution. The resulting elemental estimators, although not absolutely unbiased, are found to have very small bias, and may thus provide a useful basis for the construction of efficient estimators.

DIRECT DETECTION OF PICOSECOND PULSES EMITTED BY AN INJECTION LASER WITH ACTIVE MODE LOCKING.

An Agat-SF linear-scan streak image-converter camera was used to record output pulses of 2. 7 psec duration generated by an injection laser with an external dispersive resonator operated in the active mode-locking regime. The duration of the pulses was determined by the reciprocal of the spectral width and the product of the duration and the spectral width was 0. 30.

Quantitative structure-property relationship studies on n-octanol/water partitioning coefficients of PCDD/Fs

Based on some fundamental quantum chemical descriptors computed by PM3 Hamiltonian, by the use of partial least-squares (PLS) analysis, a significant quantitative structure-property relationship (QSPR) model for logK(ow) of polychlorinated dibenzo-p-dioxins and dibenzo-p-furans (PCDD/Fs) was obtained. The QSPR can be used for prediction. The intermolecular dispersive interactions and thus the bulkness of the PCDD/Fs are the main factors affecting the logK(ow). The more chlorines in the PCDD/F molecule, the greater the logK(ow) values. (C) 2001 Elsevier Science Ltd. All rights reserved.