On the influence of massless scalar and vector electromagnetic fields on the singularity character in anisotropic cosmology

It is shown that, for the scalar-tensor cosmology (STC) by Jordan-Brans-Dicke (JBD), in general anisotropic solution the oscillatory mixmaster regime near the singularity will be destroyed by the scalar source-free field and replaced by monotonousV ₃-collapse into the point or into the line and plane (only in caseG0) even in the presence of the primordial source-free electromagnetic (EM) field.     

On periodic orbits of the second generation and regions of stability

A part of the familyh of retrograde periodic orbits of the restricted problem (μ=0.5) is examined in relation to the families of periodic orbits of the second generation branching from it. Many such families are determined and the significance of the configuration of their characteristics for the determination of the boundary of the stability region around this part ofh is discussed.     

Probabilities and distribution of monsoon rainfall in normal, flood and drought years over India

Summary The paper deals with the variability of summer-monsoon rainfall during normal, flood and drought years over India. During flood years the monsoon rainfall increases mostly all over parts of the country and large area less than 100 cm isohytel covers Orissa and adjoining Madhya Pradesh. During drought years the rainfall amount decreases over the entire country and isohytel of 100 cm shrinks to almost a point. The variability of monsoon rainfall from flood to normal to drought years depends upon the number of depression/low-pressure area which form over the North Bay and move inland. To understand the intraseasonal and interannual variability of the monsoon rainfall, daily and seasonal anomalies has been performed by using the Empirical Orthogonal Function analysis. Further Empirical Orthogonal Function (EOF) analysis is carried out on these data to find out the nature of rainfall distribution in different monsoon categories namely normal, flood and drought years. This technique thus serves to identify spatial and temporal patterns characteristics of possible physical significance. Received July 25, 2000/Revised September 26, 2000     

Inter-decadal modulation of the impact of ENSO on Australia

 The success of an ENSO-based statistical rainfall prediction scheme and the influence of ENSO on Australia are shown to vary in association with a coherent, inter-decadal oscillation in surface temperature over the Pacific Ocean. When this Inter-decadal Pacific Oscillation (IPO) raises temperatures in the tropical Pacific Ocean, there is no robust relationship between year-to-year Australian climate variations and ENSO. When the IPO lowers temperature in the same region, on the other hand, year-to-year ENSO variability is closely associated with year-to-year variability in rainfall, surface temperature, river flow and the domestic wheat crop yield. The contrast in ENSO’s influence between the two phases of the IPO is quite remarkable. This highlights exciting new avenues for obtaining improved climate predictions. Received: 21 October 1998 / Accepted: 27 November 1998     

DETERMINANTS OF STRUCTURE IN AQUATIC NON-PELAGIC PROTOZOAN COMMUNITIES

Although microbes have traditionally been used as models for testing ecological theory, research on the organization of these communities has largely been isolated from other areas of community ecology. Early studies indicated that microbial populations can form dynamic, interacting assemblages. Observations of distributional patterns suggest that certain deterministic forces regulate community structure. It appears that protozoans are tolerant of a wide range of environmental conditions although evidence for this is largely based on gross environmental analyses. Laboratory studies have suggested the importance of negative and positive biotic interactions in determining community membership, but little field evidence for this exists. The importance of transport processes in controlling community composition is being increasingly recognized. All three types of processes likely act to regulate the colonization and successional dynamics of these communities. A simple model is presented to promote the devel     

Catastrophic Tohoku earthquake of March 11, 2011, in Japan

The results of the comparative analysis of parameters of the Tohoku earthquake (Honshu Island, Japan) of March 11, 2011, 05:46 UTC and its aftershocks are presented.     

GEOPHYSICAL STUDIES OF WATER LEAKAGES FROM RESERVOIRS*

Considerable water leakages from reservoirs make it difficult to attain the planned storage capacity. In some cases water leakages give rise to suffusion followed by catastrophes. Until recently methods for locating water leakages were extremely imperfect. Geophysical methods offer good prospects in this direction. For solving these problems, it is effective to use streaming potential measurements, water flow rate observations and thermometry. Laboratory experiments were carried out in connection with the fact that water leakages from reservoirs are characterized by negative anomalies of natural currents; the more filtration discharge, the higher these anomalies are. As a result, the relationship governing the intensity of streaming potential and sand granulometric composition, electrolyte concentrations and other factors were revealed. To determine the velocity of water flowing to leakage sites, a special device, based on the relationship between the temperature of a heated body and its resistance, is applied. This device simultaneously makes it possible to measure the water medium temperature. Observations at reservoir sites were effected by moving along the reservoir non-polarizable potential electrodes and water velocity devices. Recordings were carried out automatically by the recording device of the logging apparatus. Under the conditions of ice cover on water surfaces, measurements were made through separate points by digging holes in the ice cover. Practical field observations were carried out at reservoir sites located in regions where fissured massive rocks as well as loose sediments predominate. In the first case field experiments were carried out in alpine reservoirs, in Armenia. The major water leakages were found to be concentrated on the right bank of the reservoir. In this connection it was not only possible to locate water leakage sites, but also to evaluate their relative intensity. These data were used for planning antifiltration measures. In the second case water leakages from a reservoir located in Uzbekistan in the submontane part of the Pamirs were studied. Streaming potential anomalies and high benthonic flow rates made it possible to discover high filtrations in the base and walls of the dam. Further perfection of these methods should not only permit the determination of water leakage sites and their relative intensity, but also filtration discharges in absolute units.     

Geodetic Rotation of Neptune’s Satellites

Solar System Research - The paper considers the most significant relativistic effects in the rotational dynamics of Neptune’s satellites (Triton (N1), Naiad (N3), Thalassa (N4), Despina (N5),...     

The reconstruction of a glacial lake outburst flood using HEC-RAS and its significance for future hazard assessments: an example from Lake 513 in the Cordillera Blanca,Peru

In April 2010, an ice/rockfall into Lake 513 triggered a glacial lake outburst flood (GLOF) along the Chucchun River in the Cordillera Blanca of Peru. This paper reconstructs the hydrological characteristics of this as yet undocumented event using a 1D flood model prepared with HEC-RAS. The principle model inputs were obtained during detailed field surveys of surface characteristics and topography within the river and across the adjacent floodplain; a total of 120 cross-sections were surveyed. These inputs were refined further by eyewitness accounts and additional geomorphological observations. The flood modelling has enabled us to constrain the extent of the water surface and its elevation at each cross-section in addition to defining the peak discharge (580 m³ s^?1). These modelling results show good agreement with other information about the flood including: flood marks and minimum flood levels; the lake displacement wave height; the extent of the flooded area; and the travel time from Lake 513 to the confluence with the Santa River. This demonstrates that the model offers a reliable reconstruction of the basic hydrological characteristics of the GLOF. It provides important information about the flood intensity and significantly improves our ability to model future flood scenarios along both the studied river and within neighbouring catchments. The flood hazard, defined by the flood depth during peak discharge, shows that the majority of the damaged infrastructure (houses, bridges, and a drinking water treatment plant) was only subjected to low or medium flood intensities (defined by a maximum water depth of less than 2 m). These low flood intensities help to explain why the flooding caused comparatively minor damage despite the significant public attention it attracted.