Benthic denitrification and organic matter mineralization in intertidal flats of an enclosed coastal inlet, Ago Bay, Japan

Denitrification (as N(2) flux) and organic matter mineralization (as O(2) uptake) were simultaneously measured in the same set of core sediments from a natural sandy and a constructed muddy tidal flat of Ago Bay, Japan. Denitrification rates at both tidal flats fluctuated between ca. 2-20 micromol N(2)m(-2)h(-1) without showing a clear seasonal pattern, and appeared to be substrate limited as NO(3)(-) enrichment (final concentration ca. 225 microM) caused prompt and similar enhancements of ca. 10-folds. Organic matter mineralization rates were markedly higher at constructed muddy flat compared to those of natural sandy flat, especially in summer, and exhibited pronounced temperature dependent (p<0.01) seasonality for both tidal flats. O(2) uptake rates were generally ca. 2-3 order greater than respective denitrification rates indicating dominance of mineralization processes over N(2) losses.     

Electron-Positron Plasmas Created by Ultra-Intense Laser Pulses Interacting with Solid Targets

We discuss the necessary requirements to create dense electron-positron plasmas in the laboratory and the possibility of using them to investigate certain aspects of various astrophysical phenomena, such as gamma ray burst engines. Earth-based electron-positron plasmas are created during the interaction of ultra-intense laser pulses impinging on a solid density target. The fact that positrons can be generated during this interaction has already been demonstrated by Cowan et al. (2000). However, several questions concerning the number, energy, and dynamics of these positrons have yet to be answered. Through insight gathered from PIC simulations, we postulate that the e⁺e⁻ plasma leaves the creation region in dense jets, with relativistic energies. In order to estimate the number density of the positrons created, we begin by first experimentally measuring the hot electron temperatures and densities of such interactions using a compact electron spectrometer. Once the electron distribution is known, the positron creation rate, Γ, can be estimated. This same experimental diagnostic can also, with minor modification, measure the energy distribution of positrons. Initial estimates are that, with proper target and laser configurations, we could potentially create one of the densest arraignments of positrons ever assembled on earth. This experimental configuration would only last for a few femtoseconds, but would eventually evolve into astrophysically relevant pure electron-positron jets, possibly relevant to e⁺e⁻ outflow from black holes.     

Estimation of proportions of lithotypes using auxiliary information

The problem of estimating the proportion of lithological (ore) types in volumes of mineral deposits is considered when an auxiliary variable Z(z) is observed along with the lithology L(x) at x. The process {Z(x)} is assumed to be stationary and an assumption on the statistical relationship between {Z(x)} and {L(x)} processes is made. Consequently, the second-order stationarity of {L(x)} is not required. A method using the kriged distribution of the auxiliary variable is proposed. A case study illustrating the procedure is given.     

Geography of advice seeking

Despite limited research on access to advice services, it has long been assumed that access is related to geographic proximity [e.g. Blacksell, M., 1990. Social Justice and access to legal services: a geographic perspective. Geoforum 21 (4), 489–502]. The current study uses data from the English and Welsh Civil and Social Justice Survey, a large-scale nationally representative survey of respondents’ experience of and response to civil and social justice problems [Pleasence, P., 2006. Causes of Action: Civil Law and Social Justice, second ed. TSO, Norwich], to examine the impact of proximity to mainstream advice services on awareness and utilisation of services. In general, proximity of advice services had a relatively modest impact on both awareness and advice seeking. However, proximity did impact upon mode of contact and there was some evidence of difference in strategy (particularly more inaction) for isolated individuals without use of motorised transport. The suitability of different modes of advice provision for particular demographic groups are discussed, as well as implications for service delivery.     

Improving Large Area Population Mapping Using Geotweet Densities

Many different methods are used to disaggregate census data and predict population densities to construct finer scale, gridded population data sets. These methods often involve a range of high resolution geospatial covariate datasets on aspects such as urban areas, infrastructure, land cover and topography; such covariates, however, are not directly indicative of the presence of people. Here we tested the potential of geo‐located tweets from the social media application, Twitter, as a covariate in the production of population maps. The density of geo‐located tweets in 1x1 km grid cells over a 2‐month period across Indonesia, a country with one of the highest Twitter usage rates in the world, was input as a covariate into a previously published random forests‐based census disaggregation method. Comparison of internal measures of accuracy and external assessments between models built with and without the geotweets showed that increases in population mapping accuracy could be obtained using the geotweet densities as a covariate layer. The work highlights the potential for such social media‐derived data in improving our understanding of population distributions and offers promise for more dynamic mapping with such data being continually produced and freely available.     

Fluidity of land use patterns over the last century in and around the Baroda Urban Complex,Gujarat state

The fluidity of land-use patterns over the last century in and around the Baroda Urban Complex has been worked out using Survey of India topographic maps (1876–78, 1959–60) and SPOT satellite imagery (1988). The most striking feature of this study was the alarming loss of non-built up areas comprising agricultural land to urban sprawl. In 1876–78, non-built up land constituted 701.30 sq. km out of a total of 714 sq. km whereas in 1988, it was reduced to 625.27 sq. km. This urban growth pattern would not be conducive for sustainable development.     

Rice-acreage estimation for Orrisa using remotely sensed data

Rice is one of the most important foodgrains grown in India. Attempts have been made to estimate kharif rice acreage of Orissa state since 1986 using digital remote sensing data from Landsat MSS/TM and/or IRS-1A. Accuracies of the estimates obtained have been evaluated against BES (Bureau of Economics and Statistics) estimate. This paper describes the methodology adopted for rice acreage estimation of Orissa state, the results obtained for three years, i.e. 1986–87, 1988–89 and 1989–90, and their accuracy.     

Debris control on glacier thinning—a case study of the Batal glacier,Chandra basin,Western Himalaya

Complex factors such as climate, glacial geometry, topographical features and debris covers have significant influence on the dynamics of the Himalayan glaciers. Presence of debris covers on the surface of glaciers can significantly alter the surface energy balance and influence the climatic response of glaciers. In this study, the influence of debris covers and its impact on the ablation processes were analyzed from the in situ data collected over the surface of the Batal glacier in Chandra Basin, Western Himalaya. Almost 90 % of the ablation zone of the Batal glacier is covered by debris, 35 % of which is thick debris (>10 cm). Fourteen stakes (depth ～10 m) with increasing altitude and with varying debris thicknesses were installed to cover the whole ablation zone. Among them, four stakes represent thin debris (<2 cm), two stakes represent 2–5 cm debris thickness, two stakes represent 5–25 cm debris thickness, three stakes represent 25–50 cm debris thickness and three stakes represent >50 cm debris thickness. Our study has revealed high surface melting (?2.0 cm. w.e.d^?1) in the debris free glacier while low surface melting observed in thick debris covered ice (?0.6 cm. w.e.d^?1). Although limited to one season, this observation revealed a significant difference in the rate of surface melting as per the increasing debris thickness. Contrasting to normal ablation pattern over glaciers, Batal has experienced inverse retreat rate of ablation along with increasing altitude. A high degree of negative correlation (r = ?0.82, p < 0.05) between ablation rate and debris thickness in Batal suggest a significant control of debris thickness over ablation rate.