Effects of creating video-based modeling examples on learning and transfer

Two experiments investigated whether acting as a peer model for a video-based modeling example, which entails studying a text with the intention to explain it to others and then actually explaining it on video, would foster learning and transfer. In both experiments, novices were instructed to study a text, either with the intention of being able to complete a test (condition A), or being able to explain the content to others (condition B and C). Moreover, students in condition C actually had to explain the text by creating a webcam-video. In Experiment 1 (N = 76 secondary education students) there was no effect of study intention on learning (A = B), but explaining during video creation significantly fostered transfer performance (C > B; C > A). In Experiment 2 (N = 95 university students), study intention did have an effect on learning (C > A; B > A), but only actual video creation significantly fostered transfer performance (C > A).     

Super absorbent polymer seed coatings promote seed germination and seedling growth of <Emphasis Type="Italic">Caragana korshinskii</Emphasis> in drought

Coating seeds with water absorbent materials can improve their survival, especially for those planted in drought or barren areas. In this study, effects of five kinds of super absorbent polymers (SAPs) on seed germination and seedling growth of Caragana korshinskii under drought conditions were investigated. Our results showed that SAP coatings could significantly improve the percentage and energy of seed germination, as well as reduce the relative electrical conductivity (REC), proline, malondialdehyde (MDA), H₂O₂ content, and peroxidase (POD) activity during germination. These results implied that seeds could uptake moisture from SAP coatings to alleviate drought-induced oxidative stress and membrane damage, thus exhibiting a better vigor and germination performance. After coating C. korshinskii seeds with SAPs, more seedlings emerged and grew better. Under the combined influence of the water absorption capacity of SAP and other factors, the efficiencies of five SAP coatings are in the sequence D>E>B>A>C. The function of the SAP coating on promoting seedling survival was confirmed in Mu Us Sandy Land in Ordos, Inner Mongolia Autonomous Region, China. The average seedling number of SAP D-coated seeds increased twofold on that of naked seeds. Our results are expected to be helpful in understanding and utilizing SAP seed coatings in improving plant survival under drought conditions.     

Identification of <Emphasis Type="Italic">FECH</Emphasis> gene multiple variations in two Chinese patients with erythropoietic protoporphyria and a review

Erythropoietic protoporphyria (EPP), an autosomal dominant disease, is caused by partial deficiency of ferrochelatase (FECH), which catalyzes the terminal step of heme biosynthesis because of loss-of-function mutations in the FECH gene. To date, only a few cases have been described in Asia. In this study, we describe the clinical features of two Chinese patients with EPP, with diagnosis confirmed by the increase of free protoporphyrin in erythrocytes, detection of plasma fluorescence peak at 630–634 nm, and analysis of FECH gene mutations. Using gene scanning, we identified a small deletion in the FECH gene (c.973 delA) in one proband (patient A) and a pathogenic FECH mutation (c.1232 G>T) in the other (patient B) and also observed some nucleotide variations (c.798 C>G, c.921 A>G, IVS1?23 C>T, IVS3+23 A>G, IVS9+35 C>T, and IVS3?48 T>C) in these patients. The family pedigree of patient A was then established by characterization of the genotype of the patient’s relatives. We also analyzed the potential perniciousness of the missense mutation with bioinformatic software, Polyphen and Sift. In summary, Chinese EPP patients have similar manifestations to those of Caucasians, and identification of the Chinese FECH gene mutations expands the FECH genotypic spectrum and may contribute to genetic counseling.     

Learning to work in the creative and cultural sector: new spaces,pedagogies and expertise

The paper questions the link that policy‐makers assume exists between qualifications and access to employment in the creative and cultural (C&C) sector. It identifies how labour market conditions in the C&C sector undermine this assumption and how the UK’s policy formation process inhibits education and training (E&T) actors from countering these labour market conditions. It demonstrates how non‐government agencies (‘intermediary organizations’) are creating new spaces to assist aspiring entrants to develop the requisite forms of ‘vocational practice’, ‘social capital’ and ‘moebius strip’ (i.e., entrepreneurial) expertise to enter and succeed in the sector. It concludes by identifying a number of: (a) new principles for the governance of E&T at the national level; (b) pedagogic strategies to facilitate ‘horizontal’ transitions into and within the C&C sector; and (c) skill formation issues for all E&T stakeholders to address.     

Blended university teaching using virtual learning environments: conceptions and approaches

This paper reports findings from a phenomenographic investigation into blended university teaching using virtual learning environments (VLEs). Interviews with 25 Computer Science teachers in Greek universities illuminated a spectrum of teachers’ conceptions and approaches from ‘teacher-focused and content-oriented’, through ‘student-focused and content-oriented’, to ‘student-focused and process-oriented’. Using VLEs was described as a means of supporting: A—information transfer; B—application and clarification of concepts; C—exchange and development of ideas, and resource exploration and sharing; D—collaborative knowledge-creation, and development of process awareness and skills. The study suggests that pedagogical beliefs and circumstances underpinning face-to-face teaching are more influential in shaping approaches to blended VLE use than VLE system features. The authors propose that the findings could be used to inform educational enhancement initiatives and that there is a need for further discipline-focused research on blended teaching.     

Numerical research on the anti-sloshing effect of a ring baffle in an independent type C LNG tank

Liquid sloshing can be suppressed by the installation of baffles. The influence of a ring baffle on sloshing reduction is investigated based on an analysis of parameter sensitivity through computational fluid dynamics (CFD) simulation. Firstly, a series of liquid sloshing experiments with a liquefied natural gas (LNG) independent type C model tank is designed to validate the numerical method. Four definition parameters of the ring baffle, the height (H), the position installation (P), the inclined angle (θ), and the thickness (t), are selected as effective factors, and the efficiency of sloshing reduction is used as the comparison criterion. Research cases of parameter sensitivity are designed by orthogonal tests and computed by a validated numerical method. It is found that the thickness has little effect but the other parameters, especially the height, have significant influence in suppressing sloshing. The directions of improvement of the significant actors are analyzed. The effective height of the ring baffle is discussed numerically with different excitation angles. It is demonstrated that increasing the height of the ring baffle will not bring further improvement in efficiency of sloshing reduction after it exceeds 20% of the tank diameter.     

Within-event learning contributes to value transfer in simultaneous instrumental discriminations by pigeons

Following simultaneous discrimination training with pigeons, in which responding to the S−was reinforced on half of the trials and responding to the S− was never reinforced, we examined the effect on the S− of presenting the S− by itself and the effect on the S+ of presenting the S− by itself (relative to an S− or an S− for which there had been no single-stimulus presentations). For Group A−, responding to the S− presented by itself was always reinforced, whereas for Group A−, such responding was extinguished. For Group B−, responding to the S− presented by itself was always reinforced, whereas for Group B+, responding was extinguished. Although both Group A+ and Group A−tended to avoid their associated S− (relative to a control S−), Group A+ avoided its associated S− less than did Group A−. In contrast, although for Group B−, presentation of the S− alone increased the pigeons’ preference for its associated S−(relative to a control S+), for Group B−, presentation of the S−alone had little effect on its preference for its associated S+. These results suggest that presentation of one stimulus from a simultaneous discrimination has two independent and sometimes opposite effects on the other discriminative stimulus. First, it reduces the strength of within-event conditioning between the S+ and the S−, and second, if the value of the singly presented stimulus has increased, some of its newly acquired value will transfer retroactively to the stimulus with which it was originally paired.     

Symmetries and conservation laws in classical and quantum mechanics 2. Quantum mechanics

In Part 1 of this two-part article we have spelt out, in some detail, the link between symmetries and conservation principles in the Lagrangian and Hamiltonian formulations of classical mechanics (CM). In this second part, we turn our attention to the corresponding question in quantum mechanics (QM). The generalization we embark upon will proceed in two directions: from the classical formulation to the quantum mechanical one, and from a single (infinitesimal) symmetry to a multi-dimensional Lie group of symmetries. Of course, we always have some definite physical system in mind. We also assume that the reader is familiar with the elements of quantum mechanics at the level of a standard first course on the subject. Operators will be denoted with an overhead caret, e.g., $ \hat A,\hat G,\hat U $ \hat A,\hat G,\hat U , etc., while $ [\hat A,\hat B] = \hat A\hat B - \hat B\hat A $ [\hat A,\hat B] = \hat A\hat B - \hat B\hat A is the commutator of $ \hat A $ \hat A and $ \hat B $ \hat B .     

基于二维光子晶体带隙的研究

应用平面波展开法对二维光子晶体分别在E偏振和H偏振下的带隙进行仿真计算,寻找到空气圆柱在背景基质硅中排列的四方和三角晶格光子晶体出现最大带隙时的孔隙率r/a=0.48,并算出它们的最大带隙宽度.对于四方晶格,最大完全带隙宽度ΔGmax=0.017（ωa/2πc）,归一化频率（ωa/2πc）范围在Δω=（0.448-0.456）,对于三角晶格,最大完全带隙宽度可达ΔGmax=0.076（ωa/2πc）,归一化频率（ωa/2πc）范围在Δω=（0.455-0.531）.研究结果对在实验上制作空气圆柱在背景基质硅中排列的四方和三角晶格光子晶体提供理论指导.     

三角形中一类半圆最值问题

研究了三角形中的一类半圆,这类半圆的直径所在的直线或者把三角形分成两个三角形,或者经过三角形的一条边,且在三角形内．揭示了面积最大的这一类半圆的圆心在三角形的边上．     

基于三维模型网格子集属性的数字水印算法

提出了一种基于三维模型网格子集的新型盲水印算法。算法以三维模型网格中的网格子集为载体,提取三维模型的三角形面片数据,根据三角形相似四元组（TSQ）法计出边长比和宽高比,通过阈值控制定位嵌入基元,最后根据水印信息值修改网格子属性ID嵌入水印。水印提取过程则通过对嵌入基元定位后,查询属性ID值计算完成。实验结果表明:该算法对于几何变换和剪切、噪声攻击等都具有较好的鲁棒性。     

Analysis of a load application point in spline coupling teeth

The objective of this paper is to investigate the position of the resultant force in involute spline coupling teeth due to the contact pressure distribution for both ideal and misaligned conditions. In general, spline coupling teeth are in contact all along the involute profile and the load is far from uniform along the contact line. Theoretical models available in publications consider the resultant contact force as it is applied at the pitch diameter, and this study aims to evaluate the error introduced within the confines of a common approximation environment. This analysis is carried out through using finite element method （FEM） models, considering spline couplings in both ideal and misaligned conditions. Results show that the differences between the load application diameter and pitch diameter are not very obvious in both ideal and misaligned conditions; however, this ap- proximation becomes more important for the calculation of the tooth stiffness.     

Polymorphisms in genes involved in folate metabolism as maternal risk factors for Down syndrome in China

Objective: To explore the relationship between genetic polymorphisms in methylenetetrahydrofolate reductase (MTHFR), methionine synthase reductase (MTRR), the central enzymes in folate metabolism that affects DNA methylation and synthesis, and the risk of Down syndrome in China. Methods: Genomic DNA was isolated from the peripheral lymphocytes of 64 mothers of children with Down syndrome and 70 age matched control subjects. Polymerase chain reaction and restriction fragment length polymorphism were used to examine the polymorphisms of MTHFR 677C→T, MTRR 66A→G and the relationship between these genotypes and the risk of Down syndrome was analyzed. Results: The results show that the MTHFR 677C→T polymorphism is more prevalent among mothers of children with Down syndrome than among control mothers, with an odds ratio of 3.78 (95% confidence interval (CI), 1.78～8.47). In addition, the homozygous MTRR 66A→G polymorphism was independently associated with a 5.2-fold increase in estimated risk (95% CI, 1.90～14.22). The combined presence of both polymorphisms was associated with a greater risk of Down syndrome than the presence of either alone, with an odds ratio of 6.0 (95% CI, 2.058～17.496).The two polymorphisms appear to act without a multiplicative interaction. Conclusion: MTHFR and MTRR gene mutation alleles are related to Down syndrome, and CT, TT and GG gene mutation types increase the risk of Down syndrome.     

美国高等农业教育发展道路与模式探索

美国高等农业教育的形成和发展与美国政府在不同时期实施的<西北部法令>、<莫里尔法案>、<哈奇法案>、<第二个莫里尔法案>、<史密斯-利弗法>等密切相关;美国高等农业教育的最初施教模式有五种:新建农工类大学、新建综合性大学农科类学院、综合性大学中新增的农科学院、综合性大学中增设的农科课程和已有的农科类院校强化高等农业教育等;经过一百多年的发展,早期的农工院校大多都改名和综合发展成为综合性大学,综合性大学中的农科类院系已成为美国高等农业教育的施教主体.     

谐振式无线电能传输系统耦合机构优化设计

通过四线圈结构磁谐振式无线电能传输系统的电路模型推导出其传输效率表达式,用两线圈模型对参数进行初步设计得出谐振线圈的半径、匝数、线径等参数．利用四线圈模型对参数进行优化,调整线圈之间的互感使系统获得最大传输效率．通过两线圈模型和四线圈模型进行系统参数设计和分析,既保证了模型分析的准确性,又简化了谐振线圈设计过程,为谐振式无线电能传输系统的优化设计提供了理论依据．     

互动优化的增量三角剖分算法

当前三角化文献中一般只介绍点云的三角化方法,几乎没有文献注意到点云三角化过程中与用户互动的过程,按用户的要求进行点云的三角化。本算法是一种增量算法,为了提高算法是实用性,算法将剖分信息按照点的不同位置存储到不同的对应边链表和三角形链表中,以降低边和三角形的搜索操作时间,提高三角化的速度;算法中采用了加点剖分中同步优化和初步剖分后用户随意多次优化的多重优化方案提高剖分三角形的质量,并且剖分中同步优化和用户再次优化分别采用最小角最大化优化准则和曲率最小优化准则,使剖分拟合表面更加光顺。通过点云剖分的实例结果显示,该算法具有速度极快、占用内存少、形成三角表面质量高,程序运行界面友好等优点。     

Adaptive ant-based routing in wireless sensor networks using Energy*Delay metrics

To find the optimal routing is always an important topic in wireless sensor networks （WSNs）. Considering a WSN where the nodes have limited energy, we propose a novel Energy^＊Delay model based on ant algorithms （＂E＆D ANTS＂ for short） to minimize the time delay in transferring a fixed number of data packets in an energy-constrained manner in one round. Our goal is not only to maximize the lifetime of the network but also to provide real-time data transmission services. However, because of the tradeoff of energy and delay in wireless network systems, the reinforcement learning （RL） algorithm is introduced to train the model. In this survey, the paradigm of E＆D ANTS is explicated and compared to other ant-based routing algorithms like AntNet and AntChain about the issues of routing information, routing overhead and adaptation. Simulation results show that our method performs about seven times better than AntNet and also outperforms AntChain by more than 150% in terms of energy cost and delay per round.     

阳江话声调实验研究

运用实验语音学的方法对当代阳江话声调的音高、调长和音强进行研究,把该方言声调的实际情况客观地描写出来,为阳江话的深入研究提供参考。根据实验结果,音高调值为阴平22,阳平42,上声21,阴去214,阳去55,上阴入23,下阴入21,上阳入55。时长的结果为阴平>阴去>阳平>上声>阳去>上阴入>下阴入>上阳入。除阳去为前强型,上阴入为双峰型外,其他声调的音强类型都属于中强型。     

The effect of feature-target intervals in conditional discriminations on acquisition and expression of conditioned nictitating membrane and heart rate responses in the rabbit

Nictitating membrane (NM) and heart rate (HR) responses were investigated in a conditional discrimination (A→X+ vs. B→X−), using feature-target intervals of 0, 5, 15, and 45 sec. Conditional control of NM responses, but not of HR responses, was acquired to the 400-msec X stimulus in all the groups tested. However, differential conditioning of both the NM and the HR responses to A versus B feature cues appeared for the three shorter intervals. Following acquisition, all the rabbits were tested with the four different feature-target intervals. All the groups showed a gradient of NM responding to X, in which the highest level of responding occurred at or near the interval used in training. The results are discussed with respect to the relationship of simple conditioning of the feature cues to their control over responding during presentation of the target stimulus, the putative role of HR as an index of preparatory processes during presentation of feature cues, and mechanisms of temporal specificity in conditional discriminations.     

群机器人目标围捕系统设计与性能测试

提出了利用4辆性能一致的飞思卡尔智能小车组成智能微群系统,其中3辆进行围捕任务,1辆作为入侵机器人。在笛卡尔坐标系下建立半径为4 m的圆,3辆智能小车组成一个内切于圆的等边三角形。然后通过3条不同的入侵轨迹以及不同的围捕距离完成了对入侵机器人的围捕测试。实验验证了4辆小车都能在程序的控制下完成指定动作,并能够完成对目标3种不同路径的围捕,围捕率超过70%,对今后群体机器人的研究与发展具有参考价值。