Decrease of 2800 MHz solar radio emission associated with a moving dark filament before the flare of May 19, 1969

A decrease in the total flux at 2800 MHz, or a negative burst was observed 15 min before the onset of the short duration, impulsive burst of May 19, 1969 at 14:30 UT and continued for another 16 min. It had been recognized originally in the records from the Algonquin Radio Observatory only as a fluctuation in a long enduring, gradual rise and fall event which had commenced at 12:40 UT. A detailed account of the radio flux variations in relation to the optical activity as described by Vorpahl (1973) is given and indicates that the onset of the negative burst and the southward motion of a dark filament are associated.Presented at 140th Meeting of the American Astronomical Society, June 1973, Columbus, Ohio.     

Generalizations of the Jacobian integral

The restricted problem of three bodies is generalized to the restricted problem of 2+n bodies. Instead of one body of small mass and two primaries, the system is modified so that there are several gravitationally interacting bodies with small masses. Their motions are influenced by the primaries but they do not influence the motions of the primaries. Several variations of the classical problem are discussed. The separate Jacobian integrals of the minor bodies are lost but a conservative (time-independent) Hamiltonian of the system is obtained. For the case of two minor bodies, the five Lagrangian points of the classical problem are generalized and fourteen equilibrium solutions are established. The four linearly stable equilibrium solutions which are the generalizations of the triangular Lagrangian points are once again stable but only for considerably smaller values of the mass parameter of the primaries than in the classical problem.     

Single-Site Phase Velocity Measurement

Mikumo & Aki attempted to determine phase velocities at a single site using seismometers and strainmeters oriented in the same horizontal direction. For the five earthquakes studied, they found a good agreement with the theoretically predicted velocities for body waves and, in some cases, for surface waves. Rodgers showed that for long periods (> 100 s), horizontal acceleration and tilt cannot easily be separated instrumentally, and King et al. have shown that near-station heterogeneities may result in azimuthal effects not considered by Mikumo & Aki. We rederive the method for single-site phase velocity determinations taking into account both of these effects. Our method uses strain and vertical acceleration measurements because the vertical acceleration record is neither affected by site effects nor contaminated by tilt.     

Environmental governance through information: China and Vietnam

In the field of environmental governance information is starting to become increasingly important, not least because of globalization and the information and communication technologies revolution. The notion of informational governance is a recent coinage that acknowledges the (partial) switch from regulatory‐based forms of governance to information‐based modes. In the information‐rich centres and nodes of the network society, where information is widely produced, disseminated and accessible, this might prove analytically useful. But what are the contours of informational governance in information‐poor environments? This paper looks into the (limited) emergence of informational governance arrangements in environmental protection in two cases characterizing the informational periphery: China and Vietnam.     

《联合国荒漠与荒漠化年》简报

The UN should not confuse deserts with desertification. Deserts are good: they have biodiverse ecosystems and rich human cultures and histories. Deserts are not necessarily desertified. In contrast, desertification is bad: it is associated with degraded e…     

台湾地区湖泊水库沉积速率初步探讨

对1989－1991年期间，在台湾地区采集的5个湖泊的沉积物岩芯和22个湖泊水库的表层沉积物，进行了沉积物超量210Pb活性的分析，以探讨其沉积速率。其中，小鬼湖沉积物岩芯取部分样品进行14C定年，以与210Pb所得结果比较。结果表明，数千年来，台湾高山湖泊、次高山湖泊的沉积速率相当稳定，除万里池外，大多介于0．06－0．16cm／a之间。火山湖的210Pb活性较一般湖泊高，这是由于火山湖当地安山岩及地下水释出较多的210Pb所致，但这并不意味其沉积速率慢。所以应用210Pb对火山湖沉积物定年时，须作特别修正。平地湖泊目前沉积速率，除了大埔水库高达6．42cm／a外，大多介于0．5—3、2cm／a之间，比高山湖泊的沉积速率高约10－20倍。另外，由水库淤沙资料显示1），历年平均沉积速率都比目前的沉积速率快数倍，其中以石门、白河、乌山头、阿公店4个水库的平均沉积速率较快。