The geochemistry of uranium occurrences and speciation in groundwater of Chinnar sub basin,South India

An attempt has been made in Chinnar sub basin of Dharmapuri district, South India to isolate the geochemistry of uranium occurrences in groundwater. The geology of the area is mainly of charnockite and granite gneiss. Groundwater samples were collected for two different seasons post and pre monsoon in two different litho units (granite gneiss and charnockite) and analysed for major, minor and uranium concentrations. Higher uranium (18.45 μg L^?1) has been recorded during pre monsoon season in granite gneiss with increasing pH. The saturation index calculation for the groundwater isolated minerals like uaraninite, coffinite, haiweeite and soddyite to be precipitating and uranium oxides like UO_2.25, UO_2.25beta, UO_2.33beta as oversaturated. The Eh-pH diagram attempted represents solubility of uraninite within the pH range of 6.0 to 8.0. The study isolate uranium in groundwater of the study area is controlled by the presence of (U₄O₉) uranium oxide.     

A Spatially-Analytical Scheme for Surface Temperatures and Conductive Heat Fluxes in Urban Canopy Models

In the urban environment, surface temperatures and conductive heat fluxes through solid media (roofs, walls, roads and vegetated surfaces) are of paramount importance for the comfort of residents (indoors) and for microclimatic conditions (outdoors). Fully discrete numerical methods are currently used to model heat transfer in these solid media in parametrisations of built surfaces commonly used in weather prediction models. These discrete methods usually use finite difference schemes in both space and time. We propose a spatially-analytical scheme where the temperature field and conductive heat fluxes are solved analytically in space. Spurious numerical oscillations due to temperature discontinuities at the sublayer interfaces can be avoided since the method does not involve spatial discretisation. The proposed method is compared to the fully discrete method for a test case of one-dimensional heat conduction with sinusoidal forcing. Subsequently, the analytical scheme is incorporated into the offline version of the current urban canopy model (UCM) used in the Weather Research and Forecasting model and the new UCM is validated against field measurements using a wireless sensor network and other supporting measurements over a suburban area under real-world conditions. Results of the comparison clearly show the advantage of the proposed scheme over the fully discrete model, particularly for more complicated cases.     

Hypoxia in the northern Gulf of Mexico: Does the science support the Plan to Reduce,Mitigate, and Control Hypoxia?

We update and reevaluate the scientific information on the distribution, history, and causes of continental shelf hypoxia that supports the 2001 Action Plan for Reducing, Mitigating, and Controlling Hypoxia in the Northern Gulf of Mexico (Mississippi River/Gulf of Mexico Watershed Nutrient Task Force 2001), incorporating data, publications, and research results produced since the 1999 integrated assessment. The metric of mid-summer hypoxic area on the LouisianaTexas shelf is an adequate and suitable measure for continued efforts to reduce nutrients loads from the Mississippi River and hypoxia in the northern Gulf of Mexico as outlined in the Action Plan. More frequent measurements of simple metrics (e.g., area and volume) from late spring through late summer would ensure that the metric is representative of the system in any given year and useful in a public discourse of conditions and causes. The long-term data on hypoxia, sources of nutrients, associated biological parameters, and paleoindicators continue to verify and strengthen the relationship between the nitratenitrogen load of the Mississippi River, the extent of hypoxia, and changes in the coastal ecosystem (eutrophication and worsening hypoxia). Multiple lines of evidence, some of them representing independent data sources, are consistent with the big picture pattern of increased eutrophication as a result of long-term nutrient increases that result in excess carbon production and accumulation and, ultimately, bottom water hypoxia. The additional findings arising since 1999 strengthen the science supporting the Action Plan that focuses on reducing nutrient loads, primarily nitrogen, through multiple actions to reduce the size of the hypoxic zone in the northern Gulf of Mexico.     

Sr-isotope stratigraphy of the Upper Jurassic of central Portugal (Lusitanian Basin) based on oyster shells

Strontium isotope stratigraphy was performed on oyster shells from the Late Jurassic of the Lusitanian Basin (central Portugal). This represents the first approach to obtain numerical ages for these strata. The new chronostratigraphic data provide a more precise age determination of several units. After a basin-wide hiatus sedimentation in the Late Jurassic is proven in the Cabo Mondego and Cabaços formations to resume as early as the Middle Oxfordian. The Alcobaça formation can be placed in the latest Late Oxfordian to Late Kimmeridgian, while data from the upper part of the Abadia Formation indicate an Early to Late Kimmeridgian age. The Farta Pao formation ranges from the latest Kimmeridgian to the latest Tithonian. The largely synchronous Sobral, Arranhó I, and Arranhó II members are overlain by the late Early to Late Tithonian Freixial Member. The brief, local carbonate incursion of the Arranhó I member marks the Kimmeridgian–Tithonian boundary. Oysters are shown once more to be suitable for strontium isotope studies. Their calcitic shells are often unaffected by diagenesis. In particular for marginal marine Jurassic and Cretaceous strata, where belemnites are usually absent, oysters may serve as a valuable tool for isotope stratigraphy.     

85 Peg A: what age for a low-metallicity solar-like star?

We explore the possible evolutionary status of the primary component of the binary 85 Pegasi, listed as a target for asteroseismic observations by the MOST satellite. In spite of the assessed 'subdwarf' status, and of the accurate distance determination from the Hipparcos data, the uncertainties in the metallicity and age, coupled with the uncertainty in the theoretical models, lead to a range of predictions on the oscillation frequency spectrum. Nevertheless, the determination of the ratio between the small separation in frequency modes, and the large separation as suggested by Roxburgh, provides a very good measure of the star age, quite independent of the metallicity in the assumed uncertainty range. In this range, the constraint on the dynamical mass and the further constraint provided by the assumption that the maximum age is 14 Gyr limits the mass of 85 Peg A to the range from 0.75 to  0.82 M_⊙  . This difference of a few hundredths of a solar mass leads to well detectable differences both in the evolutionary stage (age) and in the asteroseismic properties. We show that the age determination which will be possible through the asteroseismic measurements for this star is independent either of the convection model adopted or the microscopic metal diffusion. The latter conclusion is strengthened by the fact that, although metal diffusion is still described in an approximate way, recent observations suggest that real stars suffer a smaller metal sedimentation compared with the models.     

Estimation of abl Parameters Using the Vertical Velocity Measurements of an Acoustic Sounder

The friction velocity, the surface heat flux and the height of the Atmospheric Boundary Layer (ABL) are important parameters. In this work, vertical velocity variance ( _w ² ) and wind velocity structure parameter (C _v ² ) profiles estimated by acoustic sounder measurements are used, along with similarity relations, to estimate these parameters in the unstable Atmospheric Boundary Layer and the friction velocity in the stable one. The data were collected by two acoustic sounders with different height range and resolution under various atmospheric conditions (stability) and at two experimental sites in different terrain. The C _v ² profiles are estimated using gate difference of the vertical velocity measurements and the assumption of local isotropy. The vertical velocity data are corrected for the significant effects of noisy measurements and sampling volume averaging on the _w ² and C _v ² estimations using original techniques that are presented in this work. The results of the similarity method using acoustic sounder data are compared against estimates of the corresponding atmospheric parameters obtained from direct measurements. The comparison confirms the ability of the method to provide reasonably accurate estimates of these parameters especially in the middle of the day.     

New-type urbanization in China: Predicted trends and investment demand for 2015–2030

The future development of new-type urbanization has drawn great attention from both the government and public alike. In this context, the present study had three related research aims. Firstly, it sought to predict the urbanization and population dynamics in China at both national and provincial levels for the period of 2015 to 2030. Secondly, on this basis, it sought to examine the spatial variation of urbanization given the predicted national urbanization rate of 70.12%. Thirdly, it sought to estimate and evaluate the national and provincial demands of investment in the development of new-type urbanization. The main conclusions from this study were as follows: (1) The population size and urbanization rate will reach 1.445 billion and 70.12%, respectively, from 2015 to 2030. (2) The demographic dividend will vanish when the population pressure reaches its maximum. During this period, there will be 70.16 million urban population born. The suburban population that becomes urbanized will be 316.7 million, and thus the net increase in urban population will reach 386 million. (3) Although the urbanization rate of every Chinese province will increase during 2015–2030, it will do so unequally, while differences in urbanization quality among provinces will also be substantial. In some provinces, moreover, the urbanization quality is not compatible with their eco-social development. (4) A total of 4,105,380 billion yuan is required to fund new-type urbanization and the investment demand for each province varies greatly; for example, Guangdong province requires the most funding, amounting to approximately 148 times that required by Tibet, the province in least need of funding. In the final part of this study, policy suggestions concerning the investment of the new-type urbanization are put forward and discussed.     

Spatial variation in river runoff into a coastal area — An ecological approach

Carbon and nitrogen stable isotopes were used to investigate spatial variation in terrestrial particulate organic matter (POM) input to a coastal area off the Tagus river estuary. Isotopic variation in higher trophic level organisms was also examined, along the coast. This study was carried out in late summer, after a period of 3 months of low river flow. The overall aim was to determine if under such conditions the coastal area is enriched by the river plume and, particularly, if lower secondary productivity should be expected in some areas. Spatial variation was detected as a gradient of decreasing terrestrial input with increasing distance from the river. It was concluded that terrestrial carbon input was also incorporated into higher trophic levels and that organisms with lower mobility are more sensitive to the gradient in terrestrial input. Even in low flow conditions the whole fishing area remained under the influence of the river plume, which still accounted for 24% of the total POM 30 km from the river mouth. Additionally, δ¹⁵N values indicated pollution input from the river Tagus.