鲫幼鱼易钓性与标准代谢及形态特征的关联

【目的】考察鲤科(Cyprinidae)鱼类的标准代谢率(Standard metabolic rate)及形态参数与易钓性是否存在关联。【方法】以广布种鲤科鱼类鲫(Carassius auratus)幼鱼为实验对象,在(25±0.5)℃条件下测定体质量相近、体格健康的40尾幼鱼的标准代谢率,随后在实验室环境中连续进行5d垂钓,每日垂钓20尾幼鱼即停止当日垂钓活动。【结果】1)第1d被钓出幼鱼的标准代谢率高于未被钓出幼鱼,具有统计学意义(p<0.05);随后连续4d中被钓出幼鱼与未被钓出幼鱼的标准代谢率之间的差异均不具有统计学意义。另外,每日被钓出幼鱼与未被钓出幼鱼的体质量之间的差异也无统计学意义,但被钓出幼鱼的体长在第3d和第5d大于未被钓出幼鱼,且具有统计学意义(p<0.05),并且被钓出幼鱼的肥满度在第3d高于未钓出组,具有统计学意义(p<0.05)。2)在5d的连续垂钓中,被钓上5次的幼鱼有3尾,被钓上1~4次的幼鱼分别为7,7,6,10尾,仅7尾幼鱼从未被钓出,单因素方差分析显示不同被钓出频次的幼鱼的标准代谢率之间差异不具有统计学意义。3)对5d中均被钓出的幼鱼的钓出顺序进行分析,发现它们每日被钓排序在整体上保持一致,而幼鱼的平均被钓次序号与它们的标准代谢率和形态参数均无统计学意义上的相关性。【结论】鲫幼鱼的首次被钓经历并不影响自身再次被钓;在体质量相近条件下,鲫的易钓性与外部形态(如体质量、体长或肥满度等)以及维持代谢有关。
     

Reduction of Pt Usage in Fuel Cell Electrocatalysts Using Carbon Nanotubes and Non-Pt Metals

The high-priced and limited Pt constitutes a high barrier to commercialization of fuel cells. Pt is essential for the electrode catalyst of polymer electrolyte fuel cells （PEFCs）. A reduction in Pt usage is one of the key requirements for the commercialization of fuel cells for use in everyday life, because of its high price and limited availability, and the difficulty of finding suitable substitutes. Non-Pt fuel cell catalysts will decrease the demand for Pt by PEFCs, enabling more Pt to be available for use in other essential products, and make fuel cells more popular. The cheaper Mo2C is known to possess similar catalytic activities and electronic structures to Pt. Carbon black （CB） is widely used as the support for Pt nanoparticles. However,     

黄土高原东南部宋家店黄土剖面L9中地磁记录异常

对黄土高原东南部三门峡地区宋家店黄土剖面L8～S12段详细的磁性地层学和岩石磁学研究表明:Matuyama/Brunhes(M/B)界线位于L8黄土层的底部,Jaramillo极性亚时的顶、底界线分别位于L10的中部和L12的底部.黄土和古土壤地层的磁组构保持了原生沉积组构的特点,所记录的剩磁没有遭受到明显的后期扰动.在L9黄土层中记录了2次地磁场异常,认为由重磁化的可能性较小,而磁极性漂移事件的解释更为合理.推算它们的年龄分别与Kamikatsura(0.886Ma)和Santa Rosa(0.922Ma)地磁漂移事件接近,相对古强度研究结果显示,上述地磁漂移事件期间地球磁场强度减弱.     

从关联性记忆错觉的毕生发展看记忆的适应性特质

记忆重构的过程会导致歪曲或错误.关联性记忆错觉是一种最常见的错误记忆,体现了个体在认知资源有限时对语义梗概信息的适应性利用,这是记忆具有适应性特质的一种体现.另一方面,记忆的适应性还体现为在特定的情景需求下,个体能够通过一定的策略(如充分加工项目特异性信息)抑制关联性记忆错觉的发生,以保持精确记忆.本文从利用梗概表征和抑制关联性记忆错觉两种能力的毕生发展透视了记忆的适应性特质的年龄特征.将来可从记忆演化的角度获得更多关于记忆适应性的证据.     

Hidden magnetic excitation in the pseudogap phase of a high-T(c) superconductor

The elucidation of the pseudogap phenomenon of the high-transition-temperature (high-T(c)) copper oxides-a set of anomalous physical properties below the characteristic temperature T* and above T(c)-has been a major challenge in condensed matter physics for the past two decades. Following initial indications of broken time-reversal symmetry in photoemission experiments, recent polarized neutron diffraction work demonstrated the universal existence of an unusual magnetic order below T* (refs 3, 4). These findings have the profound implication that the pseudogap regime constitutes a genuine new phase of matter rather than a mere crossover phenomenon. They are furthermore consistent with a particular type of order involving circulating orbital currents, and with the notion that the phase diagram is controlled by a quantum critical point. Here we report inelastic neutron scattering results for HgBa(2)CuO(4+δ) that reveal a fundamental collective magnetic mode associated with the unusual order, and which further support this picture. The mode's intensity rises below the same temperature T* and its dispersion is weak, as expected for an Ising-like order parameter. Its energy of 52-56?meV renders it a new candidate for the hitherto unexplained ubiquitous electron-boson coupling features observed in spectroscopic studies.     

基于核因子分析的捷联惯组稳定性评估技术

当前捷联惯组的稳定性评价方法单一,严重影响了使用单位对捷联惯组的使用效率。针对捷联惯组各个误差系数两次测试之差线性相关性较弱的特点,本文应用统计学习理论中的核化原理将因子分析这一线性特征提取算法推广至非线性特征提取算法,并改进了传统的因子综合评价方法,将其用于捷联惯组的稳定性评估。数值实验结果证明了本文提出的核因子分析方法的有效性。     

Late Paleozoic magmatism in South China:Oceanic subduction or intracontinental orogeny?

A gneissic granite with an U-Pb age of 313±4 Ma was found in northeastern Fujian Province,South China.It is an S-type granite characterized by high K2O,Al2O3 and low SiO2,Na2O contents with high A/CNK ratio of 1.22 for the whole rock.Zircons with stubby morphology from the gneissic granite yield 206 Pb/238 U ages ranging from 326 to 301 Ma with a weighted average age of 313±4 Ma,and negative εHf(t) values from -8.35 to -1.74 with Hf model ages (TCDM) of 1.43 to 1.84 Ga.This S-type granite probably originated from late Paleoproterozoic crust in intracontinental orogeny.Integrated with previous results on paleogeographic reconstruction of South China,the nature of Paleozoic basins,Early Permian volcanism and U-Pb-Hf isotope of detrital zircons from the late Paleozoic to early Mesozoic sedimentary rocks,we suggest the occurrence of a late Paleozoic orogeny in the eastern Cathaysia Block,South China.This orogenic cycle includes Late Carboniferous (340-310 Ma) orogeny (compression) episode and Early Permian (287-270 Ma) post-orogenic or intraplate extension episode.Therefore,the late Paleozoic magmatism in the southeastern South China probably occurred during the intraplate orogeny rather than the arc-related process.     

Opposing effects of polyglutamine expansion on native protein complexes contribute to SCA1

Spinocerebellar ataxia type 1 (SCA1) is a dominantly inherited neurodegenerative disease caused by expansion of a glutamine-encoding repeat in ataxin 1 (ATXN1). In all known polyglutamine diseases, the glutamine expansion confers toxic functions onto the protein; however, the mechanism by which this occurs remains enigmatic, in light of the fact that the mutant protein apparently maintains interactions with its usual partners. Here we show that the expanded polyglutamine tract differentially affects the function of the host protein in the context of different endogenous protein complexes. Polyglutamine expansion in ATXN1 favours the formation of a particular protein complex containing RBM17, contributing to SCA1 neuropathology by means of a gain-of-function mechanism. Concomitantly, polyglutamine expansion attenuates the formation and function of another protein complex containing ATXN1 and capicua, contributing to SCA1 through a partial loss-of-function mechanism. This model provides mechanistic insight into the molecular pathogenesis of SCA1 as well as other polyglutamine diseases.     

Unusual magnetic order in the pseudogap region of the superconductor HgBa2CuO4+delta

The pseudogap region of the phase diagram is an important unsolved puzzle in the field of high-transition-temperature (high-T(c)) superconductivity, characterized by anomalous physical properties. There are open questions about the number of distinct phases and the possible presence of a quantum-critical point underneath the superconducting dome. The picture has remained unclear because there has not been conclusive evidence for a new type of order. Neutron scattering measurements for YBa(2)Cu(3)O(6+delta) (YBCO) resulted in contradictory claims of no and weak magnetic order, and the interpretation of muon spin relaxation measurements on YBCO and of circularly polarized photoemission experiments on Bi(2)Sr(2)CaCu(2)O(8+delta)(refs 12, 13) has been controversial. Here we use polarized neutron diffraction to demonstrate for the model superconductor HgBa(2)CuO(4+delta) (Hg1201) that the characteristic temperature T* marks the onset of an unusual magnetic order. Together with recent results for YBCO, this observation constitutes a demonstration of the universal existence of such a state. The findings appear to rule out theories that regard T* as a crossover temperature rather than a phase transition temperature. Instead, they are consistent with a variant of previously proposed charge-current-loop order that involves apical oxygen orbitals, and with the notion that many of the unusual properties arise from the presence of a quantum-critical point.