Assessment of man-made and natural hazards in the surroundings of hydropower projects under construction in the beas valley of northwestern Himalaya

Mountain ecosystem,on the earth,has plenty of natural resources. In Himachal Pradesh all the rivers are snowfed and therefore rich in water resources. These resources have been supporting enough for the generation of electricity through introducing hydropower projects since the last decade. However,every developmental activity has its own negative impacts on the surrounding environment. Due to the fragile nature of topography and delicacy of ecology of the Himalaya,it results in lot of disturbances because of high degree of human interferences like construction of major hydropower projects. The increased extent of geological hazards,such as landslides,rock fall and soil erosion,have mainly due to alike developmental interventions in the natural ecosystem. So understanding and analysing such impacts of the hydropower projects have mainly been on the environment in various forms but natural hazards have been frequent ones. The present study,therefore,focuses mainly on the Parbati Stage Ⅱ (800 MW) and the Parbati Stage Ⅲ (520 MW) hydropower projects; both of which fall within the Kullu district of Himachal Pradesh. Based on the perception survey of the local communities,the existing land use pattern,status of total acquired land of the residents by hydropower projects,frequent natural hazards and resultant loss to the local communities due to upcoming construction of hydropower projects surrounding to the Parbati Stage Ⅱ and Ⅲ have been analysed in the paper. Also,the preventive measures to mitigate these adverse impacts have been suggested to strengthen these projects in eco-friendly manner in the mountain context.     

Motion of two planets with periods commensurable in the ratio 2∶1 solutions of the hori auxiliary system

It is shown that the Hori auxiliary system for the motion of two planets, whose motions around the Sun have commensurable periods in the ratio 2 : 1, is completely integrable and, an intermediate orbit that includes the effects of the resonance is obtained. The difficulties of classifying some solutions as librations or circulations are discussed.     

A multidisciplinary approach to evaluating impacts of shellfish aquaculture on benthic communities

The impact of suspended mussel culture (Mytilus edulis, M. trossulus) on the benthos of a small Nova Scotia cove (7 m depth) was assessed using meehods involving both benthic metabolism and community structure. Due to deposition of mussel feces and pseudofeces, sedimentation rate was higher under the mussel culture lines than at an adjacent reference site of similar sediment texture. Porewater profiles of sediment sulfate and sulfide indicated greater anaerobic metabolism at the mussel site than at the reference site, but sulfide was absent from the upper centimeters of sediments under the mussels. Seasonal measures of sediment oxygen demand showed little change between sites, but maximum rates of ammonium release at the mussel site were twice the highest rates measured at the reference site. Abundance of benthic macrofauna was higher at the reference site, but biomass was generally lower. Biomass at the mussel site was dominated by molluscs (Ilyanassa spp. andNucula tenuisulcata), that were attracted to mussels fallen from the culture and/or enriched organic matter due to biodeposition. Species diversity was lower at the reference site due to the dominance of the polychaeteNephtys neotena. Abundance-biomass comparisons (ABC method) of faunal analysis did not indicate any impact of biodeposition at this site: however, disturbance did not result in a typical assemblage of small opportunistic species anticipated with this method. Cluster analysis of macrofauna usually provided a clear separation between the sites. Since the contruction of a causeway (1968), foraminifera species composition showed a temporal response to temperature changes in the cove by shifting toward calcareous species, but assemblages downcore showed little or no relationship to aquaculture impacts. Although there is a shift toward anaerobic metabolism at the mussel lines, the impact of mussels falling to the sediments was more noticeable in benthic community structure than was any impact due to organic sedimentation or hypoxia. In general the impact of aquaculture on the benthos appeared to be minor. Furtyher assesment of these consequences may mandate both taxonomic and energetic approaches to impact assessment.     

Relativistic beaming in the central components of double radio quasars

Using a large sample of 78 well-observed double quasars, we have investigated several consequences of the relativistic beaming model. In this model the ratio of the strengths of the central component and outer lobes of a double source depends on whether the jet axis lies close to or away from the line of sight, If this is the actual situation, the fraction of emission from the core,f _c, may be used as a statistical measure of the orientation of the source and should be correlated with other source parameters which also depend on the inclination of the jet axis to the line of sight. We findf _c to be anticorrelated with the overall projected linear size of the extended emission but to exhibit a positive correlation with both the observed degree of misalignment from a collinear double structure, and the ratio of separations of the outer hotspots from the central component. As might be expected from these relationships, we also find sources of smaller projected linear sizes to appear more misaligned and the degree of misalignment to be correlated with the ratio of separations of the outer hotspots. All these correlations are consistent with the predictions of the relativistic beaming model.     

Surface temperature differences between minerals in crystalline rocks: Implications for granular disaggregation of granites through thermal fatigue

Thermal expansion differences between minerals within rocks under insolation have previously been assumed to drive breakdown by means of granular disaggregation. However, there have been no definitive demonstrations of the efficacy of this weathering mechanism. Different surface temperatures between minerals should magnify thermal expansion differences, and thus subject adjacent minerals to repeated stresses that might cause breakdown through fatigue failure. This work confirms the existence of surface temperature differences between minerals in granitic rocks under simulated short-term temperature fluctuations so as to discriminate their potential for initiating granular disaggregation. The influence of colour, as a surrogate for albedo, and crystal size, as a function of thermal mass are specifically identified because of their ease of quantification. Four rock types with a range of these properties were examined, and subjected to repeated short-term temperature cycles by radiative heating and cooling under laboratory conditions. Results show that while albedo is the main control for overall and individual maximum temperatures, crystal size is the main factor controlling higher temperature differences between minerals. Thus, stones with large differences of mineral sizes can undergo magnified stresses due to thermal expansion differences.     

Producer Services Research in Europe*

Four directions in producer services research in Europe are identified: the economic role of producer services for urban and regional development; the location of advanced producer services; the role of regional structures and innovative “milieu”; and local development and labor markets. Issues for future research include the role of producer services in the urban structuring and/or restructuring of world cities; the relation between producer services and interregional disparities; the integration of producer services into networks; and the impacts of the liberalization of producer services.     

The value of a physically based model versus an empirical approach in the prediction of ephemeral gully erosion for loess-derived soils

A data set on soil losses and controlling factors for 58 ephemeral gullies has been collected in the Belgian loess belt from March 1997 to March 1999. Of the observed ephemeral gullies, 32 developed at the end of winter or in early spring (winter gullies) and 26 ephemeral gullies developed during summer (summer gullies). The assessed data have been used to test the physically based Ephemeral Gully Erosion Model (EGEM) and to compare its performance with the value of simple topographical and morphological indices in the prediction of ephemeral gully erosion.Analysis shows that EGEM is not capable of predicting ephemeral gully cross-sections well. Although conditions for input parameter assessment were ideal, some parameters such as channel erodibility, critical flow shear stress and local rainfall depth showed great uncertainty. Rather than revealing EGEM's inability of predicting ephemeral gully erosion, this analysis stresses the problematic nature of physically based models, since they often require input parameters that are not available or can hardly be obtained.With respect to the value of simple topographical and morphological indices in predicting ephemeral gully erosion, this study shows that for winter gullies and summer gullies, respectively, over 80% and about 75% of the variation in ephemeral gully volume can be explained when ephemeral gully length is known. Moreover, when previously collected data for ephemeral gullies in two Mediterranean study areas and the data for summer gullies formed in the Belgian loess belt are pooled, it appears that one single length (L)–volume (V) relation exists (V=0.048 L^1.29; R²=0.91). These findings imply that predicting ephemeral gully length is a valuable alternative for the prediction of ephemeral gully volume. A simple procedure to predict ephemeral gully length based on topographical thresholds is presented here. Secondly, the empirical length–volume relation can also be used to convert ephemeral gully length data extracted from aerial photos into ephemeral gully volumes.