The Distribution of Water and Suspended Sediment Flow during Spring Flood in the Forked Channel of the Lower Ob (Within Khanty-Mansi Autonomous Area)

Water Resources - The forked channel is a rare and poorly known type of branching channel, the distribution of flow in which is of key importance for water transport, economic activities, and water...     

Sorption–Desorption Transformation of the Runoff of Dissolved Microelements at River–Sea Geochemical Barrier (Based on Data of Experimental Laboratory Simulation)

Water Resources - A new method was used for experimental simulation of the sorption–desorption transformation of microelement composition of the adsorbed complex of solid substances of river...     

Seagrass importance for a small-scale fishery in the tropics: The need for seascape management

Small-scale fisheries (SSF) in tropical seascapes (mosaics of interconnected mangroves, seagrasses and corals) are crucial for food and income. However, management is directed mostly to corals and mangroves. This research analyzes the importance of seagrasses compared to adjacent ecosystems in Chwaka Bay, Zanzibar, Tanzania. Using fish landings; the study investigated: location of fishing effort, fish production (biomass and species), and monetary benefits (aggregated value and per capita income). Seagrasses were the most visited grounds providing highest community benefits. Per capita benefits were equivalent to those from corals and mangroves. All three habitats provided income just above extreme poverty levels; however catches from seagrass appeared more stable. Seagrass are key ecosystems supporting SSF and protection and management are urgently needed. Adoption of a seascape approach considering all ecosystems underpinning SSF and the social aspects of fishing and a shift in emphasis from pure conservation to sustainable resource management would be desirable.     

用1Hz GPS观测数据推导中强震震源过程的能力:2008年日本岩手—宫城内陆地震例子

通过反演研究2008年日本岩手—宫城内陆地震（M～6.9）,说明了用1Hz全球定位系统（GPS）观测数据推导中强震（M6级）震源过程的能力。比较了此次地震采样率为1Hz的GPS观测波形,发现与强震仪记录波形有很好的一致性。由于震源区及其周围有足够多的GPS台站很好地记录到了地面运动,因而使我们仅仅采用1Hz的GPS观测数据就可进行波形反演。反演的结果与大地测量和强震仪数据联合反演的结果相当一致,如地震矩（Mw～6.9）、累积滑动量分布和破裂传播等。这种一致性证明,采样率为1Hz的GPS观测数据不仅能用来推导M6级中强震破裂过程的动态特征,而且能用来推导其持久（或静态）的滑动。     

Data reporting norms for 40Ar/39Ar geochronology

Data reported in ⁴⁰Ar/³⁹Ar geochronology studies are commonly insufficient to allow computation of ages. This deficiency renders it difficult to compare ages based on different standards or constants, and often hinders critical evaluation of the results. Herein are presented an enumeration of the data that should be reported in all ⁴⁰Ar/³⁹Ar studies, including a discussion in support of these requirements. The minimum required data are identified and distinguished from parameters that are useful but may be derived from them by calculation. Finally, recommendations are made for metadata needed to document age calculations (e.g., from age spectrum or isochron analyses).     

Effect of common point selection on coordinate transformation parameter determination

The use of satellite positioning techniques commonly requires a transformation from a Conventional Terrestrial coordinate system to a Geodetic coordinate system, or vice versa. For such a transformation, the main problem is the determination of transformation parameters between these coordinate systems. The transformation parameters are estimated by a least-squares process using “common” points, i.e., those points whose coordinates are known in both systems. Therefore, the precision of so estimated transformation parameters is closely related to certain characteristics of the common points. In this contribution, we have formulated some theoretical relations between the transformation parameters and the number and the distribution of common points, and corroborated the theoretical results numerically, using a simulated geodetic network.     

Magnetic properties of basalts and geodynamics of the rift zone in the southern Red Sea

Magnetic properties of young rift basalts in the southern Red Sea are studied in detail. It is found that basalt samples dredged in the rift zone are characterized by a large spread in magnetic parameters. The magnetic properties of the basalts are shown to indicate a complex evolution of the Red Sea rift zone. Titanomagnetite grains of the basalts are mostly affected by single-phase oxidation processes and have preserved paleomagnetic information. However, basalts discovered near the rift axis yield evidence of multiphase oxidation of titanomagnetite grains, which is untypical of young oceanic basalts. These basalts have high Curie points and large values of the natural remanent magnetization and Koenigsberger parameter. The corresponding samples were taken in nontransform zones where rocks have experienced the action of significant tectonic forces and, moreover, anomalous geomagnetic field patterns correlate with the position of these zones. Using the magnetic properties of the basalts, the northern segment of the rift axis is relocated.     

Model study of the effect of the main ionospheric trough on oblique HF radiowave propagation

The purpose of this paper is to study the effect of the main ionospheric trough location on the form of oblique sounding ionograms on the Murmansk-St. Petersburg subauroral radio path. Using a mathematical model of the high-latitude ionosphere, we have calculated four different distributions of electron density along the radio path. One of the distributions has been obtained when the trough is absent, and the remaining three distributions contain troughs of approximately identical depth and width but located at different distances from the ends of the radio path. Using the program of two-dimensional ray tracing, we numerically synthesized oblique-incidence ionograms for each of the four obtained distributions of electron density. The calculations have shown that the location of the main ionospheric trough affects considerably the shape of oblique-incidence ionograms.