Determining Field Correlations Produced by Stars from the Study of Spectral Changes in Double Slit Experiment

Experiments are performed to determine the coherence properties of wave fields, produced by the broadband stellar sources on the earth surface, from the study of spectral changes produced on interference in the Young's double slit experiment. The spectral degree of coherence obtained experimentally in this study for four bright stars in the wavelength range from 325 nm to 660 nm is in close agreement with the value that is expected theoretically from the known angular diameter of the stars. It is shown that the spectral degree of coherence obtained experimentally by this spectral interferometric technique could be used to determine the angular diameter of stars. This revised version was published online in July 2006 with corrections to the Cover Date. This revised version was published online in July 2006 with corrections to the Cover Date.     

From richer to poorer: zircon inheritance in Pomona Island Granite,New Zealand

Previous U–Pb zircon dating of the Pomona Island Granite (PIG) pluton (South Island, New Zealand) yielded either Permo-Carboniferous or Late Jurassic ages for five samples essentially indistinguishable in their field, petrographic, and geochemical characteristics. Detailed cathodoluminescence imaging and LA-ICP-MS dating of zircon in new and previously dated samples reveal that portions of the pluton contain either delicately oscillatory-zoned Late Jurassic zircon grains with rare Permo-Carboniferous cores, or Permo-Carboniferous grains with ubiquitous but thin Late Jurassic rims. Based on zircon dissolution-overgrowth textures, zircon rim and core trace element compositions, and the limited extent of sub-solidus rock recrystallisation textures, the bipartite age distribution is unlikely to reflect variable Pb-loss or metamorphic re-equilibration. Magmatic Zr-saturation temperatures were ≥851°C for samples dominated by Jurassic zircon and ≤809°C for samples with a predominance of Permo-Carboniferous zircon. Together, these data are consistent with PIG magmas having been derived from partial melting of a Permo-Carboniferous felsic igneous source at variable temperature wholly in the Late Jurassic (157 ± 3 Ma). The lowest temperature melts would have been incapable of dissolving significant amounts of pre-existing zircon and consequently generated inheritance-rich magmas, with the very thin rims on the pre-existing zircon grains the only evidence of the Late Jurassic magmatic age. As the partial melting temperature increased and nearly all pre-existing zircon grains dissolved into the magma, an inheritance-poor batch of melt was generated, which precipitated new zircon grains upon crystallisation. Concentrations of major and many trace elements in both magma batches may have been buffered by retention of residual quartz and feldspar in the source, which would explain the limited geochemical differences between inheritance-rich and inheritance-poor portions.     

Geochemical and mineralogical characteristics of recent clastic sediments from lower Godavari river: Implications of source rock weathering

The major, trace and rare earth elements geochemistry and clay mineral compositions in the river bed sediments from lower reaches of Godavari river suggest that they are derived from weathering of felsic rocks. Trace and rare earth elemental compositions indicate evidence of sedimentary sorting during transportation and deposition. Lower concentrations of transition elements, such as V, Ni and Cr imply enrichment of felsic minerals in these bed sediments. The REE pattern in lower Godavari sediments is influenced by the degree of source rock weathering. The light rare earth elements (LREE) content are indicating greater fractionation compared to the heavy rare earth elements (HREE). A striking relationship is observed between TiO₂ and gZREE content suggesting a strong control by LREE-enriched titaniferous minerals on REE chemistry. Shale-normalized REE pattern demonstrate a positive Eu anomaly, suggesting weathering of feldspar and their secondary products, which are enriched in Eu. Chondrite-normalised REE pattern is characteristic of felsic volcanic, granites and gnessic source rocks. Trace elemental compositions in sediments located near urban areas suggest influence of anthropogenic activity. Chemical Index of Alteration (CIA) is high (avg. 65.76), suggesting a moderate chemical weathering environment. X-ray diffraction analysis of clay fraction shows predominance of clay minerals that are formed because of the chemical weathering of felsic rocks.     

Numerical simulation of the impact of sediment supply and streamflow variations on channel grain sizes and Chinook salmon habitat in mountain drainage networks

Climatically driven changes in streamflow and hillslope sediment supply could potentially alter stream surface grain size distribution patterns and thereby impact habitat for a number of threatened and endangered in‐stream fish species. Relatively little is known about hydrograph (shape, peak flow) influence or the relative importance of chronic and episodic hillslope inputs on channel conditions. To better understand these external drivers, we calculated sediment routing through a gravel‐bedded river network using a one‐dimensional (1D) bedload transport model. We calculated changes in grain sizes and estimated Chinook salmon habitat suitability caused by a dry year and an extreme flood hydrograph, and chronic (diffusive, overland flow) or pulse (landslide, debris flow) hillslope sediment supplies. To obtain accurate channel conditions, a relatively high reference Shields stress, representative of steep mountain streams, was needed. An extreme event flood without any hillslope sediment inputs caused widespread bed coarsening and a decrease in aquatic habitat. Chronic sediment input combined with this hydrograph eliminated any changes in grain size and habitat, although when combined with a dry year flow, caused systematic bed fining. The influence of a given hydrograph therefore highly depends on the hillslope sediment supply. Regardless of the flow hydrograph or sediment pulse timing, grain size distribution or location, pulse sediment inputs did not cause widespread grain size changes despite being 100 times the total chronic input volume. Widespread and continuous hillslope sediment inputs may influence channel grain sizes and aquatic habitat more than a single discrete sediment pulse. Depending on the magnitudes of flow hydrograph and sediment supply alterations, climate change may induce no differences in grain sizes or very dramatic changes with significant consequences for long‐term sustainability. Copyright © 2013 John Wiley & Sons, Ltd.     

Summer spatial patterns of the fish community in a large,shallow, turbid coastal lake

Several water quality parameters, marginal vegetation, and the fish community in Lake Ellesmere, a large, shallow, turbid lake situated on the east coast of the South Island, New Zealand, were sampled along selected transects in late summer to determine species spatial patterns. Thirteen species offish were caught, with seven of them comprising major populations, although only four of these were adequately sampled by the method used—they included inanga (Galaxias maculatus), common smelt {Retropinna retropinna), shortfinned eel (Anguilla australis), and common bully (Gobiomorphus cotidianus). Inanga were almost exclusively confined to areas on the western side of the lake which has a convoluted shoreline with a variety of small embayments with scattered vegetation along the margins. Common smelt occupied both marginal and offshore areas, but they too were more abundant along the margins particularly on the western side. Both the common bully and shortfinned eel were widespread and abundant in the lake, although their abundance and biomass were higher within the vicinity of the lake outlet, major inflowing tributaries, and other marginal habitats. All three species of flounders of the genus Rhombosolea were poorly represented in our samples. However, in commercial catches they were reasonably abundant, with the sand flounder (R. plebeia) and yellowbelly (R. leporina) being more common in offshore than inshore catches, whereas the black flounder (R. retiaria) showed no difference in the catches between areas. Our overall findings are consistent with the hypothesis that bottom‐dwelling species (eels, bullies, flounders) are more widely distributed than free‐swimming forms (inanga, common smelt), which were largely confined to areas sheltered from prevailing winds. The highly turbid nature of the lake, primarily because of re‐suspension of fine bottom sediments by frequent winds, is considered an important factor in the distribution of the fish fauna.     

Distribution of viral and bacterial pathogens in a coastal canal community

Significant concentrations of human enteric viruses and bacteria were found to be present in the water and sediment of a coastal canal community into which secondarily treated sewage was being discharged.     

Flood Inundation Hazard Modelling Using CCHE2D Hydrodynamic Model and Geospatial Data for Embankment Breaching Scenario of Brahmaputra River in Assam

In many flood prone river basins, water inundates vast areas of land causing loss of life and heavy damage to the dwellings in flood plains. It also impacts agricultural productivity and cause severe economic losses. One of the reasons for flooding in plains of Brahmaputra valley in north east India is embankment breaching. In this study, an attempt was made for probabilistic flood hazard modelling of July 2008 embankment breaching scenario of Brahmaputra river at Matmara village, Lakhimpur district in Assam, based on various numerical simulations with the help of Center for Computational Hydro science and Engineering hydro-dynamic model. The methodology was applied over 2146 km² flood prone area. Data inputs in the study include: Advanced Spaceborne Thermal Emission and Reflection Radiometer Digital Elevation Model, Pre-flood and Post flood satellite images of Landsat Enhanced Thematic Mapper Plus (ETM+) and other ancillary data. The simulation was carried out for various discharge levels based on flood frequency analysis. The result of the model includes spatial variations of inundated water depth and water velocity. The results were validated by comparing it with the post-flood ETM+ data and flood situation status report of National Informatics Centre. Flood hazard maps were prepared by carrying out a spatial analysis of simulated inundation depth and velocity. It was seen that the majority of flooded area fell into the very high and high categories. This information can be used to plan appropriate cost effective flood mitigation schemes.     

Policy making for renewable energy in India: lessons from wind and solar power sectors

It is clear that developing countries will have to be part of the global mitigation effort to avoid ‘dangerous climate change’, and, indeed, many of them are already undertaking significant actions on multiple fronts to help address this problem, even if they have not yet taken on legally binding commitment under the United Nations Framework Convention on Climate Change (UNFCCC). Since the deployment of GHG-mitigating technologies is already a significant part of this effort and likely to be even more so in the future, drawing lessons from existing programmes can help accelerate and enhance the effectiveness of this deployment process. Accordingly, this article aims to examine the deployment of wind and solar power in India, paying specific attention to the role of public policy in incentivizing and facilitating this deployment, how these policies have evolved over time, what has shaped this evolution, and what the learning has been over this period. Through this analysis, the intention is to draw out key lessons from India's experience with deployment policies and programmes in these two sectors and highlight the issues that will need to be given particular consideration in the design of future domestic policies and international cooperation programmes to enhance the move towards climate-compatible development in India. Many of these lessons should also be relevant for other developing countries that are attempting to balance their climate and developmental priorities through the deployment of renewable energy technologies.