Sexual Dimorphism and Female Reproductive Characteristics in the Hainan Water Skink(Tropidophorus hainanus)from Hainan,South China

We studied sexual dimorphism in body size and shape and female reproductive characteristics in the Hainan Water Skink(Tropidophorus hainanus)from Hainan,South China.In our sample the largest female and male were 61.1 and 55.2 mm snout-vent length(SVL),respectively.The mean SVL was larger in adult females(52.0 mm)than in adult males(48.3 mm).Juveniles were sexually dimorphic in head length but not in other examined morphological variables.Adult males were longer in head length and shorter in abdomen length and fore-limb length than adult females of the same SVL.Ontogenetic shifts in sexual dimorphism in body shape were evident,as revealed by the fact that morphological differences between the sexes were more pronounced in adults than in juveniles.Females produced a single litter of 3–6 offspring per season from early August to early September.Litter size,litter mass and offspring(neonate)mass were positively related to female SVL.Neonate mass was independent of relative fecundity.From the above findings we draw three main conclusions.First,females are the larger sex in T.hainanus,and sexual dimorphism in body shape is more pronounced in adults than in juveniles.Second,larger female T.hainanus produce more and larger offspring and thus heavier litters than smaller ones.Third,the offspring size-number trade-off does is not evident in T.hainanus.

直流微网下的光伏可调度下垂控制方法

为了提升光伏调度的灵活性,并解决传统基于U-I下垂的光伏控制方法中的过载问题,提出了以U-dp/du下垂控制为第1层,以调度指令跟踪为第2层的分层可调度下垂控制方法。在不同的时间尺度上,实现了不同的控制目标。在短时间尺度上,U-dp/du下垂控制可以在光伏电源之间分担瞬态功率波动;在长时间尺度上,跟踪调度指令以实现电压控制或功率调节。而且,以dp/du作为控制变量实现了光伏运行模式的无缝切换,不仅避免了过载问题,还能作为调度中的功率裕量指标。最后,在硬件在环实验中验证了所提算法的有效性。

Sexual Dimorphism,Female Reproductive Characteristics and Embryonic Thermosensitivity in the Tonkin Forest Skink(Sphenomorphus tonkinensis)from Hainan,South China

We collected 75 adult Tonkin forest skinks(Sphenomorphus tonkinensis) from Hainan, South China and incubated eggs at four constant temperatures ranging from 22 ℃ to 28 ℃ to study sexual dimorphism, female reproductive characteristics and embryonic thermosensitivity. The largest male was 53.4 mm snout-vent length(SVL), and the largest female was 54.3 mm SVL. The mean SVL was slightly greater in adult females(49.9 mm) than in adult males(48.8 mm), but the difference was not significant.Head length, head width, fore-limb length and hindlimb length were longer in adult males and abdomen length was longer in adult females after accounting for SVL. Accordingly, we conclude that S. tonkinensis is basically a sexually size-monomorphic species with sexual dimorphism in head size, abdomen(trunk)length and limb size. Females laid up to two clutches of 1–4 eggs each per egg-laying season from February to May. Egg mass, clutch size and clutch mass were independent of female SVL. Embryonic stages at laying varied from Dufaure and Hubert’s stage 30 to 31. With female SVL held constant, the negative correlation between egg mass and clutch size was not significant, suggesting that the offspring(egg) sizenumber trade-off between is not evident or eggs are well optimized for size in S. tonkinensis. None of the eggs at 28 ℃ hatched;hatching success was lower at 22 ℃ than at 24 ℃ or 26 ℃. The mean incubation length was 52.9 d at 22 ℃, 40.4 d at 24 ℃ and 33.6 d at 26 ℃. Hatchlings from eggs incubated at 22 ℃,24 ℃ and 26 ℃ did not differ morphologically at hatching, suggesting that temperatures within this range do not differentially affect hatchling morphology in S. tonkinensis.

控制同步发电机加速功率的储能滑模控制器

针对电力系统功角稳定性问题,在建模分析储能与同步发电机能量交互关系的基础上,提出一种控制同步发电机加速功率的储能滑模控制器.利用滑模控制的强鲁棒性,将同步发电机的转速偏差引入滑模面,并通过控制同步发电机的加速功率,使同步发电机与电网在控制上解耦,并使同步发电机的频率恢复至额定值,从而增强系统的功角稳定性.为了削弱滑模控制中的抖振现象,采用非线性光滑函数代替滑模控制中的符号函数,得到实用化的滑模控制器.通过构造李雅普诺夫函数进行所提控制器的稳定性分析.在Matlab/Simulink的仿真测试中,对比所提控制器和参数反馈线性化控制器(PFL)、功率振荡阻尼控制器(POD)以及柔性控制器(FC)在扰动下的系统性能,结果表明所提控制器稳定时间比其他3种控制方法缩短30%以上.

基于机器学习的猪生长性状基因组预测

为了比较自动机器学习下不同机器学习模型预测部分猪生长性状与全基因组估计育种值(genomic estimated breeding value,GEBV)的性能,并寻找适合的机器学习模型,以优化生猪育种的全基因组评估方法,本研究利用来自多个公司9968头猪的基因组信息、系谱矩阵、固定效应及表型信息通过自动机器学习方法获取深度学习(deep learning,DL)、随机森林(random forest,RF)、梯度提升机(gradient boosting machine,GBM)和极致梯度提升(extreme gradient boosting,XGB)4种机器学习最佳模型。采用10折交叉验证分别对猪达100 kg校正背膘(correcting backfat to 100 kg,B100)、达115 kg校正背膘(correcting backfat to 115 kg,B115)、达100 kg校正日龄(correcting days to 100 kg,D100)、达115 kg校正日龄(correcting days to 100 kg,D115)的GEBV及其表型进行预测,比较不同机器学习模型应用于猪基因组评估的性能。结果表明:机器学习模型对GEBV的估计准确性高于性状表型;在GEBV预测中,GBM在B100、B115、D100、D115的预测准确性分别为0.683、0.710、0.866、0.871,略高于其他方法;在表型预测中,对猪B100、B115、D100、D115预测性能最好的模型依次为GBM(0.547)、DL(0.547)、XGB(0.672、0.670);在模型训练所需时间上,RF远高于其他3种模型,GBM与DL居中,XGB所需时间最少。综上所述,通过自动机器学习获取的机器学习模型对GEBV预测的准确性高于表型;GBM模型总体上表现出最高的预测准确性与较短训练时间;XGB能够利用最短的时间训练准确性较高的预测模型;RF模型的训练时间远超其他3种模型,且准确性不足,不适用猪生长性状表型与GEBV预测。

基于空间域dP/dV计算的光伏控制方法

为了消除基于扰动观测方法下的光伏系统输出稳态振荡,针对当前步长计算中dP/dV存在的零分母问题,以空间上相邻的数据计算dP/dV,去掉扰动观测,直接以dP/dV作为控制变量.在稳态下,避免了零分母问题,实现了稳态时无振荡;在动态下,高频的信号更新反馈保证了快速的动态跟踪过程.统一了最大功率跟踪模式(dP/dV=0)和功率热备模式(dP/dV<0),可以在不同的dP/dV参考值下实现优秀的输出性能.在Matlab/Simulink仿真和实物实验中,通过与传统P&O算法及最新MPPT算法的对比,证明了所提算法在最大功率跟踪性能上的优势;与基于时域dP/dV计算的控制方法对比,证明了所提算法在功率热备输出性能上的优势.

Strain effects on Li^(+) diffusion in solid electrolyte interphases:A molecular dynamics study

Dilithium ethylene dicarbonate(Li_(2)EDC) and dilithium butylene dicarbonate(Li_(2)BDC) are the common organic compositions of the solid electrolyte interphase(SEI) layers in rechargeable lithium-ion batteries.The Li^(+) diffusion in the amorphous and ordered phases of Li_(2) EDC and Li_(2) BDC under various strains has been investigated by using molecular dynamics simulations.It is found that different strains lead to diverse changes in Li^(+) diffusivity.The tensile strain makes the Li+diffusion coefficients increase in amorphous and ordered Li_(2)EDC or Li_(2) BDC,and the compressive strain makes the Li+diffusion coefficients decrease in them.The average Li+coordination number calculation,ion conductivity calculation and the calculation of the residence autocorrelation function in amorphous and ordered Li_(2)EDC or Li_(2)BDC are performed to further analyze the strain effects on Li^(+) transport in them.The factors influencing Li^(+) diffusion in amorphous and ordered Li_(2)EDC or Li_(2) BDC under the strain are discussed.

Lymphatic spreading and lymphadenectomy for esophageal carcinoma

Esophageal carcinoma(EC) is a highly lethal malignancywith a poor prognosis. One of the most important prognostic factors in EC is lymph node status. Therefore, lymphadenectomy has been recognized as a key that influences the outcome of surgical treatment for EC. However, the lymphatic drainage system of the esophagus, including an abundant lymph-capillary network in the lamina propria and muscularis mucosa, is very complex with cervical, mediastinal and celiac node spreading. The extent of lymphadenectomy for EC has always been controversial because of the very complex pattern of lymph node spreading. In this article, published literature regarding lymphatic spreading was reviewed and the current lymphadenectomy trends for EC are discussed.

不确定条件下创业投资激励政策的选择与优化

创业投资是重要的创新资本,为了得出驱动创业投资主动配置资源支持创新的激励策略,基于风险补贴与税收优惠的激励政策,构建了创业投资期权博弈模型,研究了创新性创业企业的价值不确定条件下创业投资激励政策的实施效果。结果表明:当创新项目价值不确定性小于阈值时,在加快创业投资机构的投资决策方面,税收优惠政策效果更好,反之,两种政策效果相同;当创业企业价值不确定性小于阈值时,在提高创业投资机构投资规模方面,风险补贴政策效果更好,反之,两种政策效果相同。

考虑安装基础的主机平台捆绑策略研究

软硬件平台作为新兴平台模式,不同于传统零售平台,需要消费者支出一定的费用才可以接入。因此,存在安装基础。以主机平台为例,具有安装基础的消费者可以直接购买第三方提供的搭载于主机的游戏产品,这将有利于第三方内容提供商的倾销行为,但与此同时无益于主机平台的主机的售卖。市场上可以观察到,主机平台时常进行新主机和第三方内容的捆绑,迫使有安装基础的消费者购买新主机。因此,构建了一个模型来研究安装基础对主机平台捆绑策略获利的影响,并对竞争的两个主机公司的捆绑策略获利进行了分析。我们的研究提供了主机平台在不同捆绑策略下受安装基础影响的分析,并发现安装基础并不总是对平台供应商提供正向的影响。研究还分析了竞争主机制造商的均衡选择问题,并发现在特定条件下,捆绑-捆绑策略和不捆绑-不捆绑策略均有可能作为均衡存在。

配合主网调度的配电网分布式电源主动控制策略

为了降低大量分布式电源接入配电网造成的电网潮流的不确定性,提出一种能够用于配合主网功率调度的配电网分布式电源控制策略。该策略可以实现主网对配电网在公共连接点处注入的有功和无功功率对给定参考值的跟踪,从而使整个配电网等效为可控的功率节点,使配电网具有一定的功率调度性能。同时,具有分布式电源间有功功率的分担以及平衡各分布式电源并网点处的电压的特性。该策略采用分布式一致性算法,只依赖邻居节点间的通信,不需要系统的全局信息。还给出配电网分布式电源通过控制无功实现电压平衡的阻抗条件。策略的有效性通过仿真得到了验证。

氧化石墨烯的表面改性及对尼龙6纤维的力学增强作用

为了提高尼龙6(PA6)纤维的力学性能,利用十二烷基胺(DA)对氧化石墨烯(GO)表面改性得到氨基化的氧化石墨烯(A-GO),将A-GO与PA6熔融共混纺丝制得A-GO/PA6复合纤维。通过对A-GO及A-GO/PA6复合纤维的结构表征,结果表明DA成功接枝于GO,相较于未改性的GO,A-GO的层间距增大了0.37nm,改性的A-GO与基体PA6具有良好的界面相互作用,可以实现较为均匀的分散;A-GO在PA6纤维中起异相成核作用,促进了尼龙6纤维的结晶,并诱导PA6由α晶型向γ晶型转变;A-GO/PA6复合纤维较纯PA6纤维的5%热失重温度提高了6.1~8.9℃,表现出更高的热稳定性;当A-GO的含量仅为0.1%时,复合纤维的拉伸强度是纯PA6纤维的1.4倍。

本地提供签名服务系统的设计与实现

近年来,随着浏览器更多的依赖基于HTML5/Java Script的扩展技术,Active X技术由于其兼容性差、漏洞多备受诟病,逐渐将被淘汰。目前银行系统广泛采用Active X技术,致使网上银行业务局限性大,亟需一种安全的替代技术。文章设计并实现了一种本地提供签名服务的方案和系统,能够支持不同浏览器,提供安全的数字签名服务。文章提出一种本地HTTP服务,该服务监听特定的端口,与网页脚本代码交互,验证了签名请求者的身份、网页域信息和用户的身份,完成签名工作。该系统使用密钥拆分技术,在保证密钥安全性的同时实现了隐私数据的安全存储,有极高的实用性、安全性和扩展性。

一种用于电-气互联系统运行优化的动态收缩凸松弛算法

提出了一种动态收缩凸松弛算法来解决电-气互联系统的运行优化问题。模型建立中,考虑了新能源与储能元件接入以及管存和气流方向等运行约束。所提算法利用了二阶锥松弛和凸包松弛的方法将非凸约束转换为凸约束,并通过动态收缩求解算法将电-气互联系统的运行优化问题转化为精确松弛域内的混合整数二阶规划问题加以求解。算例测试中,分别以修改的IEEE 39节点与IEEE 118节点电力系统和比利时20节点天然气系统组成的2个电-气互联系统为例,通过仿真验证了该算法有较佳的松弛精度和较快的计算速度。

Temperature acclimation affects thermal preference and tolerance in three Eremias lizards(Lacertidae)

We acclimated adult males of three Eremias lizards from different latitudes to 28℃,33℃ or 38℃ to examine whether temperature acclimation affects their thermal preference and tolerance and whether thermal preference and tolerance of these lizards correspond with their latitudinal distributions.Overall,selected body temperature(Tsel)and viable temperature range(VTR)were both highest in E.brenchleyi and lowest in E.multiocellata,with E.argus in between;critical thermal minimum(CTMin)was highest in E.multiocellata and lowest in E.brenchleyi,with E.argus in between;critical thermal maximum(CTMax)was lower in E.multiocellata than in other two species.Lizards acclimated to 28℃ and 38℃ overall selected lower body temperatures than those acclimated to 33℃;lizards acclimated to high temperatures were less tolerant of low temperatures,and vice versa;lizards acclimated to 28℃ were less tolerant of high temperatures but had a wider VTR range than those acclimated to 33℃ and 38℃.Lizards of three species acclimated to the three temperatures always differed from each other in CTMin,but not in Tsel,CTMax and VTR.Our results show that:temperature acclimation plays an important role in influencing thermal preference and tolerance in the three Eremias lizards,although the degrees to which acclimation temperature affects thermal preference and tolerance differ among species;thermal preference rather than tolerance of the three Eremias lizards corresponds with their latitudinal distributions.

Effects of Constant versus Fluctuating Incubation Temperatures on Hatching Success, Incubation Length, and Hatchling Morphology in the Chinese Skink (Plestiodon chinensis)

We incubated eggs ofPlestiodon chinensis under five constant （24, 26, 28, 30, and 32 ℃） and one fluctuating thermal regimes to examine the effects of constant versus fluctuating incubation temperatures on hatching success, incubation length, and hatchling morphology. The duration of incubation varied considerably among the six temperature treatments, whereas hatching success did not. The mean incubation length decreased as temperature increased in a nonlinear way, and increased as the thermal variance increased. Incubation temperature affected the body size （linear length and mass） and shape of hatchlings, with eggs incubated at 26, 28, and 30 ℃ producing larger and heavier hatchlings than did those incubated at 24 ℃, 32 ℃, or fluctuating temperatures. Our results showed that exposure of P. chinensis eggs to extreme temperatures for brief periods of time did not increase embryonic mortality and, in the fluctuating-temperature treatment, the thermal variance affected hatchling morphology more evidently than the thermal mean. Our results highlight the importance of the thermal variance in affecting embryonic development and hatchling morphology, and add further evidence that temperatures within the range of 26-30 ℃ are optimal for P. chinensis embryos.

Differences in Incubation Length and Hatchling Morphology among Five Species of Oviparous Phrynocephalus Lizards (Agamidae) from China

We incubated eggs of five Phrynocephalus species （P. albolineatus, P. axillaries, P. grumgrzimailoi, P. helioscopus and P. przewalskii） at three constant temperatures （24℃, 28℃ and 32℃） to examine differences in incubation length and hatchling morphology among species and among temperature treatments. We combined data from this study with those reported previously for P. frontalis and P. versicolor to examine whether embryonic stage at laying is a causal factor for interspecific variation in incubation length, and whether the phylogenetic relationship inferred from hatchling morphology is consistent with the relationship based on mitochondrial DNA data. Mean values for incubation length differed among the five species studied herein and, in all these five species, incubation length decreased at a decreasing rate as temperature increased. In none of the five species did hatchling size （snout-vent length and body mass） and other morphological variables differ among the three temperature treatments. The seven oviparous Phrynocephalus lizards found in China differ from each other in hatchling morphology, and embryonic stage at laying is a causal factor of inter- and intra-specific variation in incubation length. The phylogenetic relationship inferred from hatchling morphology is not always consistent with the currently known relationship based on mitochondrial DNA data. Data from this study and those reported previously allow the conclusion that any Phrynocephalus species may have its unique position along the axis defined by hatchling morphology.

Differences in Thermal Preference and Tolerance among Three Phrynocephalus Lizards (Agamidae) with Different Body Sizes and Habitat Use

We acclimated adults of two viviparous （Phrynocephalus guinanens＆ and P. vlangalii） and one oviparous （P. versicolor） species of toad-headed lizards （Agamidae） to 28 ℃, 33 ℃ and 38 ℃ to examine whether thermal preference （preferred body temperature, Tp） and thermal tolerance （critical thermal minimum, CTMin; critical thermal maximum, CTMax） were affected by acclimation temperature, and correlate with body size and habitat use. Both Tp and CTMax were highest in P. versicolor and lowest in P. vlangalii, with P. guinanensis in between. The two viviparous species did not differ in CTMin and thermal tolerance range, and they both were more resistant to low temperatures and had a wider range of thermal tolerance than the oviparous species. Both CTMin and CTMax shifted upward as acclimation temperature increased in all the three species. Tp was higher in the lizards acclimated to 33 ℃ than in those to 28 ℃ or 38 ℃. The range of thermal tolerance was wider in the lizards acclimated to 28 ℃ than in those to 33 ℃ or 38 ℃. The data showed that： 1） thermal preference and tolerance were affected by acclimation temperature, and differed among the three species of Phrynocephalus lizards with different body sizes and habitat uses; 2） both Tp and CTMax were higher in the species exchanging heat more rapidly with the environment, and CTMin was higher in the species using warmer habitats during the active season; and 3） thermal preference and tolerance might correlat with body size and habitat use in Phrynocephalus lizards.

Age-related Variation in Snake Venom: Evidence from Two Snakes (Naja atra and Deinagkistrodon acutus) in Southeastern China

In this study we explored electrophoretic profiles, enzymatic activities and immunoreactivity of neonate and adult venoms from two snakes （Naja atra and Deinagkistrodon acutus） coexisting in southeastern China. Age-related variation in electrophoretic profiles was found in both species and proteolytic and fibrinogenolytic activity was higher in neonate than adult venoms. Neonate D. acutus venom had higher 5＇ nucleotidase, PLA2, hyaluronidase and gelatinolytie activity, but lower esterolytic activity, than adult venom. Neonate and adult D. acutus venoms showed identical phosphomonoesterase, LAO and fibrinolytic activities. Neonate N. atra venom had higher phosphomonoesterase and LAO activity, but lower 5＇ nucleotidase, PLA2, hyaluronidase and Ache activities than adult venom. Neonate and adult N. atra venoms showed similar gelatinolytic activity. Further, age-dependent immunoreactivity was found in both species, and cross-reactions between homologous venoms and antiserums were closely related to venom composition. We speculate that age-related variation in venom characteristics is possibly driven by evolutionary forces associated with ontogenetic shifts in dietary habits, competition and predation pressure.

Tail Autotomy Does Not Increase Locomotor Costs in the Oriental Leaf-toed Gecko Hemidactylus bowringii

Tail autotomy is a defense mechanism used by many lizards to evade predators, but it entails costs. We used the oriental leaf-toed gecko Hemidactylus bowringii as a model animal to evaluate locomotor costs of tail autotomy. We removed the tail about 5 mm from the tail base from each of the experimental geckos(adult males) initially having intact tails. Tailless experimental geckos and tailed control geckos were measured for overall speed and sprint speed in both vertical and horizontal directions. Overall speed and sprint speed did not differ between tailless and tailed geckos. The influence of locomotor direction on both overall speed and sprint speed was significant, with horizontal speed being greater than vertical speed. The interaction between tail condition and locomotor direction was not significant in overall speed, but was significant in sprint speed. Tailless geckos had faster vertical sprint speed than the tailed individuals. Of the 130 field-caught adults, 59 had previously lost their tails, with most(about 61%) of them shedding their tails near the tail base. Neither the proportion of geckos with tail autotomy nor the frequency distribution of locations of the tail break differed between the sexes. Our data show that tail loss of H. bowringii occurs frequently in nature. However, tail loss does not incur locomotor costs in this gecko.