古鄱阳湖盆地东北缘白晋纪地层的新材料—兼论陆相地层清理后的问题讨论

古鄱阳湖盆地东北缘白垩系的田坂群历来趋向“二分”，但从对剖在再观察入手，认为田坂群纵向上经历了粗→细→粗的巨旋回，这种巨旋回与盆地演化规律，发展阶段相一致，因而“三分”显著，该剖面地学，9沉积学的一些新发现，不仅便于地层划分与对比，而且对盆内层序地层，岩相分析，构造演化阶段研究都具重要意义。     

Histological bone structure of Lower Cretaceous dinosaurs from southwest Istria (Croatia)

Recently discovered dinosaur bones in submerged near-shore deposits of southwest Istria include one vertebra, one femur, and two rib fragments. They all show well-developed vascularization. The large amounts of primary bone tissue in the vertebral and femoral compacta as well as in one rib fragment suggest that they belong to sub-adult animals which were growing rapidly. The structure of a second rib fragment differs in that it consists of secondary bone. The absence of lines of arrested growth is evident in all investigated bones. This suggests a sustained manner of bone deposition.     

Intracrystalline fractionation of Fe in synthetic (Fe, Mg, Zn) - bearing staurolite: a Mössbauer spectroscopic study

⁵⁷Fe-Mössbauer spectra of eleven Fe-Mg-bearing staurolite samples, synthesized at 5, 20 and 25 kbar and 680°C, ranging in composition from x_Fe?=1.00 to x_Fe?=0.15, and of two Zn-Fe-bearing staurolite samples, synthesized at 20 kbar and 700°C with x_Fe?=0.10 and x_Fe?=0.32 were collected at room temperature. The spectra reveal that about 80% of Fe_tot (in case of Fe-Mg-bearing staurolite) and about 70% of Fe_tot (in case of Fe-Zn-bearing staurolite) are located as Fe²⁺ at the three subsites Fe1, Fe2 and Fe3 of the tetrahedral T2-site. The refinement of the spectra results in almost identical values for the isomer shift (IS) (±1.0 mm/s) but significantly different values for the quadropole splitting (QS) for the three subsites which is in accordance with the different distortions of these sites. About 8% of Fe_tot (in case of Fe-Mg-bearing staurolite) and 13% of Fe_tot (in case of Fe-Zn-bearing staurolite) are located as Fe²⁺ at the octahedral M4 site, while the remainder percents of Fe_tot indistinguishably occur as Fe²⁺ at the octahedral M1 and M2 sites of the kyanite-like part of the structure. Within the whole Fe-Mg-staurolite solid solution series the Mössbauer parameters QS of the sites M4 and (M1, M2) vary systematically with composition whereas IS remains constant. There is a high negative correlation of the total Mg-content with Fe-occupation of all the Fe-bearing sites indicating a continuous substitution of Fe²⁺ by Mg on all these sites. Synthetic Fe-staurolites show no increasing occupation of the octahedral sites by two-valent cations with pressure, as was assumed by several authors.     

Negotiating changing livelihoods: The sampan dwellers of Tam Giang Lagoon, Vi?t Nam

Central Vi?t Nam is one of the most vulnerable areas in the country to natural disasters. In 1985 a major typhoon hit the Tam Giang Lagoon coastal area in the province of Th?a Tiên-Hu?, Central Vi?t Nam, with severe impacts on the sampan dwellers who lived there on boats and fished for their livelihoods. Since then, the government has attempted to resettle them on land in order to decrease their vulnerability to such events. Consequently, this process has changed the livelihood options as well as the social networks of the sampan dwellers. This study of the resettlement village of Th?y ?i?n analyses the social networks and different forms of social capital being utilised by the resettled sampan dwellers as part of their changing livelihoods and questions whether the social capital formed will indeed lead to a long term decrease in vulnerability. It is found that while bonding and linking social capital have been newly formed, the trust required for bridging social capital formation is still missing, and this in turn is hindering the possibilities of sustainable livelihood formation.     

刚性桩复合地基垫层对桩土应力比影响分析

从极限平衡理论角度对刚性桩复合地基中垫层作用机理进行分析,提出桩顶垫层厚度、垫层材料内摩擦角等参数对桩土应力分担的控制公式,推导出在已知表面应力情况下考虑桩土共同作用的桩土沉降计算公式,在此基础上提出一种桩土应力比的迭代计算方法。编制程序实现对算例的计算,总结分析计算结果并与实测值进行对比验证。     

关于桩基软弱下卧层验算的几点认识

对于国内外不同的规范、手册中对于桩基软弱下卧层验算的不同方法进行了分析。提出以下的一些建议:承台底面以上的原地基土自重在附加应力计算时可以扣除,在总应力计算时再加上;扣除的群桩实体基础四周的摩阻力应使用群桩四周地基土的摩阻力特征值,而不是极限值;对于地下室中的独立柱的桩基础和内墙的条形桩基础,应当从地下室地面而不是原地面起算进行验算。     

A search for optical polarization from the narrow-line Seyfert 1 galaxy RE J1034+396

We present spectropolarimetry data on RE J1034+396, an ultra-soft X-ray narrow-line Seyfert 1 galaxy, and find an upper limit of ∼ 0.4 to the linear polarization in the optical band. This suggests that there is no synchrotron emission in this AGN, and thus it is unlikely that RE J1034+396 is related to BL Lac objects. Furthermore, any other polarization arising from transmission through dust, or reflection from dust and electrons, must be cancelled out by geometrical effects or diluted to a high degree by unpolarized radiation.     

Spectroscopic observations of the eclipsing polar MN Hya (RX J0929–24)

We present low–medium resolution optical spectroscopy of the eclipsing AM Her system MN Hya (RX J0929–24). We determine the magnetic field strength at the primary accretion region of the white dwarf to be 42 MG from the spacing of cyclotron features visible during π ∼ 0.4–0.7. From spectra taken during the eclipse we find that the secondary has an M3–4 spectral type. Combined with the eclipse photometry of Sekiguchi, Nakada &38; Bassett and an estimate of the interstellar extinction we find a distance of ∼300–700 pc. We find unusual line variations at π ∼ 0.9: Hα is seen in absorption and emission. This is at the same point in the orbital phase at which a prominent absorption dip is seen in soft X-rays.     

A timing formula for main-sequence star binary pulsars

In binary radio pulsars with a main-sequence star companion, the spin-induced quadrupole moment of the companion gives rise to a precession of the binary orbit. As a first approximation one can model the secular evolution caused by this classical spin-orbit coupling by linear-in-time changes of the longitude of periastron and the projected semi-major axis of the pulsar orbit. This simple representation of the precession of the orbit neglects two important aspects of the orbital dynamics of a binary pulsar with an oblate companion. First, the quasiperiodic effects along the orbit, owing to the anisotropic 1/ r ³ nature of the quadrupole potential. Secondly, the long-term secular evolution of the binary orbit, which leads to an evolution of the longitude of periastron and the projected semi-major axis, which is non-linear in time.   In this paper a simple timing formula for binary radio pulsars with a main-sequence star companion is presented which models the short-term secular and most of the short-term periodic effects caused by the classical spin-orbit coupling. I also give extensions of the timing formula that account for long-term secular changes in the binary pulsar motion. It is shown that the short-term periodic effects are important for the timing observations of the binary pulsar PSR B1259–63. The long-term secular effects are likely to become important in the next few years of timing observations of the binary pulsar PSR J0045–7319. They could help to restrict or even determine the moments of inertia of the companion star and thus probe its internal structure.   Finally, I reinvestigate the spin-orbit precession of the binary pulsar PSR J0045–7319 since the analysis given in the literature is based on an incorrect expression for the precession of the longitude of periastron. A lower limit of 20° for the inclination of the B star with respect to the orbital plane is derived.