Swimming ability and its rapid decrease at settlement in wrasse larvae (Teleostei: Labridae)

Wrasses are abundant reef fishes and the second most speciose marine fish family, yet little is known of their larval swimming abilities. In August 2010 at Moorea, Society Islands, we measured swimming ability (critical speed, Ucrit) of 80 settlement-stage larvae (11–17 mm) of 5 labrid species (Thalassoma quinquevittatum [n = 67], Novaculichthys taeniourus [n = 6], Coris aygula [n = 5], Halichoeres trimaculatus [n = 1] and H. hortulanus [n = 1]) and 33 new recruits of T. quinquevittatum. Median (mdn) larval Ucrit was 7.6–12.5 cm s⁻¹. In T. quinquevittatum (n = 67), larvae of 12.5–14.5 mm swam faster (mdn 16.9 cm s⁻¹) than smaller or larger larvae (mdn 3.9 and 3.2 cm s⁻¹, respectively). Labrid larvae Ucrit is similar to that of other similar-sized tropical larvae, so labrids and species with comparable settlement sizes should have similar abilities to influence dispersal. Ucrit of T. quinquevittatum recruits decreased to 47–56% of larval Ucrit in 2 days, implying rapid physiological changes at settlement.     

Preliminary evaluation of insecticide resistance in a strain of Musca domestica (Diptera: Muscidae) from an intensive chicken farm of Northern Italy

The house fly, Musca domestica L., a relevant sanitary pest, is mainly controlled by insecticides. However, an inappropriate use of chemicals may induce resistance, treatment efficacy decline and environmental damages. We evaluated toxicity of some organophosphates, pyrethroids, spinosad and neonicotinoids by topical applications on adults of a M. domestica strain (OcRo) collected from an intensive chicken farm in Northern Italy, in comparison to a susceptible strain (s-DBF). The OcRo strain exhibited higher levels of resistance (RR??) to four pesticides in comparison to s-DBF. Spinosad and imidacloprid had very low RR??, thus were still efficient in OcRo control. We also tested resistance to pesticides in OcRo after topical applications of synergistic compounds. Hydrolases were involved in phosphorganic detoxification and cytochrome P450 monoxygenases in that of pyrethroids. These results indicate that OcRo strain is now multiresistant to organophosphates and pyrethroids, and this should be considered for an environmentally safe pest management.     

Insecticidal activity and fungitoxicity of plant extracts and components of horseradish (Armoracia rusticana) and garlic (Allium sativum)

To avoid environmental pollution and health problems caused by the use of traditional synthetic pesticides, there is a trend to search for naturally occurring toxicants from plants. Among the compounds discussed for anti-fungal and insecticidal activity, the natural extracts from garlic and horseradish have attracted considerable attention. The objective of this study is to determine the insecticidal and anti-fungal activity of Armoracia rusticana and Allium sativum L. extracts against larvae of Aedes albopictus (Skuse) and some pathogenic fungi. For the insecticidal test, horseradish and garlic extracts were prepared from fresh plants (cultivated in Emilia Romagna region) in a solution of ethanol 80 % and the two different solutions were used at different concentrations (for the determination of the lethal dose) against the fourth instar mosquito's larvae. The fungicidal test was carried out by the agar plates technique using garlic and horseradish extracts in a 10 % ethanol solution against the following organisms: Sclerotium rolfsii Sacc., Trichoderma longibrachiatum, Botrytis cinerea Pers., Fusarium oxysporum Schlecht. and Fusarium culmorum (Wm. G. Sm.) Sacc. The first results demonstrated that the horseradish ethanol extracts present only a fungistatic activity against Sclerotium rolfsii Sacc., Fusarium oxysporum Schlecht. and F. culmorum (Wm.G. Sm) Sacc. while garlic extracts at the same concentration provided a good fungicidal activity above all against Botrytis cinerea Pers. and S. rolfsii. A. rusticana and A. sativum preparations showed also an interesting and significant insecticidal activity against larvae of A. albopictus, even if horseradish presented a higher efficacy (LC?? value of 2.34 g/L), approximately two times higher than garlic one (LC?? value of 4.48 g/L).     

环境因素对六氯苯厌氧降解活性的影响

在厌氧污泥具备了较好的六氯苯（HCB）降解能力的基础上,采用标准血清瓶实验方法考察了反应温度、初始pH、摇床转速和营养元素等环境因素对厌氧污泥降解HCB活性的影响。实验设计的反应温度为25、30、35和40℃;初始pH为5.0、6.0、7.0和8.0;摇床转速为0和150r·min-1;营养元素有葡萄糖和维生素b12。用HCB浓度随时间的减少来表征微生物对其的降解活性。结果表明,反应温度对HCB的降解速率有很大影响,适宜温度为35℃左右。初始pH对HCB降解活性没有显著影响,但显示出有随初始pH增大而HCB降解活性增加的趋势。与静置条件相比,一定的混合作用有利于提高HCB的降解活性。有葡萄糖存在条件下,维生素b12对HCB的降解活性有明显的促进作用。温度及外加碳源（葡萄糖）是影响HCB厌氧降解活性的重要因素,并推测葡萄糖在HCB降解过程中提供电子供体方面发挥了重要作用。     

自适应神经网络在确定落煤残存瓦斯量中的应用

落煤残存瓦斯量的确定是采掘工作面瓦斯涌出量预测的重要环节，它直接影响着采掘工作面瓦斯涌出量预测的精度，并与煤的变质程度、落煤粒度，原始瓦斯含量、暴露时间等影响因素呈非线性关系，人工神经网络具有表示任意非线性关系和学习的能力，是解决复杂非线性，不确定性和时变性问题的新思想和新方法，基于此，作提出自适应神经网络的落煤残丰瓦斯量预测模型，并结合不同矿井落煤残存瓦斯量的实际测定结果进行验证研究，结果表明，自适应调整权值的变步长BP神经网络模型预测精度高，收敛速度快，该预测模型的应用可为采掘工作面瓦斯涌出量的动态预测提供可靠的基础数据，为采掘工作面落煤残存瓦斯量的确定提出了一种全新的方法和思路。     

基于MODIS植被指数的浑善达克沙地植被物候变化

基于近20a MODIS的2种植被指数数据，利用Logistic曲线曲率极值法和动态阈值法，对浑善达克沙地植被物候进行了提取，分析其时空变化，并利用研究结果数据，分析植被物候对高程和气象因子的响应.结果表明，2000~2019年间研究区的植被物候呈微弱波动趋势，浑善达克沙地植被返青期（SOS）主要集中在110~140d，枯黄期（EOS）主要集中在250~280d，整体呈微弱推迟趋向（0.28d/a），生长季长度（LOS）主要集中在120~170d，整体呈微弱延长趋向（0.23d/a）.在空间分布上，占研究区51.51%的区域植被SOS呈提前趋势；占研究区67.02%的区域植被EOS呈提前趋势，并且占研究区32.98%的区域植被EOS呈推迟趋势.占研究区62.71%的区域植被LOS呈延长趋势.在海拔900~1500m区间，随着海拔升高，SOS显著推迟，EOS不显著提前，LOS显著缩短.前一年11、12月和当年1、2、4月降水量对SOS有提前作用.6、7、8、9月份气温和降水都对EOS推迟有明显的作用.总的来说，浑善达克沙地植被物候与气候因子的相应规律比较复杂，表现出季节性的差别及地形的差异性.     

R/S法的土石坝施工期沉降规律及预警标准研究

为提高施工期土石坝沉降安全性,研究其具有复杂非线性特征的施工期沉降规律和相应的预警标准。基于国内某在建高土石坝的沉降数据,采用R/S法分析坝体不同高程测点、同高程测点和同测点不同时期沉降数据的Hurst指数及分形维数,提出评价坝体施工期沉降安全性的预警标准。结果表明:各测点的Hurst指数最小值为0.763,坝内各处沉降仍处于快速增长阶段;坝体下部比上部、中部比下游堆石区沉降能更快趋于稳定,且坝体下部的沉降速率已经渐趋平缓。     

民营企业安全文化模型及其实证分析

针对民营企业特点,基于交互安全文化模型,建立民营企业安全文化模型并辨识 关键元素,以赛轮金宇股份有限公司为例进行实证分析。在广泛参考国内外相关研究的 基础上,设计调查问卷,运用粗糙集ROSETTA软件对测量结果进行属性简约,最终确定 15个安全文化元素;借助MATLAB,采用熵权法确定各元素权重,然后进行可拓综合评价 。评价结果表明该企业的“高层管理者重视”一项得分为4.82,水平较高,整体文化等 级属于“良”,级别特征变量j*=3.138 1。“创造安全舒适的工作环境”、“建立合理 的奖惩制度”、“定期进行应急演练”3个方面得分偏低,是安全文化建设需要重点加 强的方面。