A Remark on the Use of a Weight Matrix in the Linear Model of Coregionalization

The linear model of coregionalization (LMC) is generally fit to multivariate geostatistical data by minimizing a least-squares criterion. It is commonly believed that weighting the criterion by inverse variances will reduce the influence of those variables with large variance. We point out that this need not be so, and that in some cases the weights will have no effect whatsoever on the estimated sill matrices. When there is an effect, it is due not to a reduction of these variables’ influence, but rather due to a lack of invariance of the minimization problem; moreover, sometimes the influence may actually increase. The correct way to reduce influence is to fit the LMC after standardizing the variables to have unit variance.     

Instruments of RT-2 experiment onboard CORONAS�CPHOTON and their test and evaluation V: onboard software, data structure, telemetry and telecommand

The onboard software and data communication in the RT-2 Experiment onboard the Coronas?CPhoton satellite is organized in a hierarchical way to effectively handle and communicate asynchronous data generated by the X-ray detectors. A flexible data handling system is organized in the X-ray detector packages themselves and the processing electronic device, namely RT-2/E, has the necessary intelligence to communicate with the three scientific payloads by issuing commands and receiving data. It has direct interfacing with the Satellite systems and issues commands to the detectors and processes the detector data before sending to the satellite systems. The onboard software is configured with several novel features like (a) device independent communication scheme, (b) loss-less data compression and (c) Digital Signal Processor. Functionality of the onboard software along with the data structure, command structure, complex processing scheme etc. are discussed in this paper.     

A composed index of critical accessibility (CICA) to healthcare services in a traditional African City

While empirical works that analyse rural–urban differentials in accessibility to health services are common in the developing countries, systematic studies focusing on intra-urban variations in accessibility to overall healthcare resources remain scant. Yet, many urban dwellers especially in the Sub-Saharan Africa have to travel long distances within the urban space to access basic health services. This study employs composed index of critical accessibility (CICA) to analyse differentials in access to health resources in Ibadan, a traditional African City. Data on healthcare centre location, ownership, doctors’ population were collected through field survey while spatial data on the administrative units and populated places were obtained from archival sources. Also, data on road networks was collected. Results show that the distribution of health facilities across local administrative units varies. In terms health facilities, Ibadan South West has 26 (36 %) of the total number while Ibadan South east has only 7 (9.8 %). The Doctor-Population Ratio also exhibits similar variations as Ibadan North has 20.5 as against 2.2, 1.9 and 0.3 for Ibadan SW, Ibadan NW and Ibadan NE respectively. The CICA analysis shows that 228,938 inhabitants are in high risk of negative accessibility while 49,234 are faced with condition of low risk of negative accessibility, which implies that a significant proportion of the population still finds it difficult to access basic health services as and when needed. The variations in the distribution of this deprived population are also noteworthy as the largest proportion of this group was localized in Ibadan NW. This has grave implication for the health and wellbeing of the population and raises once again the question of spatial equity in the delivery of urban public service. Curiously, these differences in the level of accessibility cut across administrative boundaries which brings to the fore the role of jurisdictional partitioning in ensuring equity in the delivery of urban public services. This opens a vista of research opportunity into the role jurisdictional partitioning in service provision in the urban centres.     

Measuring the impact of mitigation activities on flood loss reduction at the parcel level: the case of the clear creek watershed on the upper Texas coast

As property damage from flooding continues to increase, particularly in coastal areas, the adoption of strategies to mitigate these losses has never been more important to protecting the health and safety of coastal communities. Both structural and non-structural flood mitigation activities are being considered to buffer the adverse consequences of building structures in areas exposed to flood risk. However, little research has been conducted on the effectiveness of flood mitigation practices, particularly non-structural approaches at the parcel level. Our study addresses this lack of critical knowledge by examining the effect of mitigation activities adopted under the FEMA community rating system on insured property losses across multiple communities within the Clear Creek watershed located just south of Houston, TX and adjacent to Galveston Bay. Specifically, we statistically identify the degree to which various mitigation strategies adopted by a community reduce flood loss claims among 9,555 parcels from 1999 to 2009. Results indicate that several mitigation policies adopted at the community level result in significant savings in property damage for homeowners in the Clear Creek watershed.     

Strontium isotopic evidence for prehistoric transport of gray‐ware ceramic materials in the eastern Grand Canyon region,USA

Through a novel application of strontium (Sr) isotopic analysis, we evaluate geological sources for prehistoric ceramics in the eastern Grand Canyon region of northern Arizona, focusing on two gray‐ware traditions in the Upper Basin of the Coconino Plateau. Building on a conceptual framework for the general potential of Sr isotopes in the analysis of geological materials, we suggest that the eastern Grand Canyon is specifically well suited archaeologically and geologically for: (1) exploring the utility of Sr isotopes for ceramic provenance research and (2) testing long‐standing hypotheses that gray‐ware ceramics were invariably made with local materials. Sr isotopic compositions indicate that the ceramic samples represent at least three different geological sources, and that different raw materials were used in the manufacture of the two gray‐ware traditions found in the Upper Basin. One of the gray‐ware traditions is not compositionally consistent with local geology, indicating that either the ceramics or the raw materials were transported at least 20 km to the Upper Basin. © 2011 Wiley Periodicals, Inc.     

Multiple sources for mineralizing fluids in the Charmitan gold(-tungsten) mineralization (Uzbekistan)

Mineral assemblages present within the Charmitan gold(-tungsten) quartz-vein mineralization have been investigated for their cathodoluminescence behaviour, chemical composition and noble gas isotope systematics. This inventory of methods allows for the first time a systematic reconstruction of the paragenetic relationships of quartz, scheelite, sulphides and native gold within the gold mineralization at Charmitan and provides the basis to utilise noble gas data in the discussion of sources and evolution of ore-forming fluids. The vein quartz is classified into four generations based on microscopic and cathodoluminescence investigations. Quartz I shows intense brittle deformation as associated scheelite I. Undeformed scheelite II overgrows scheelite I and has lower light rare earth element and higher intermediate rare earth element contents as well as higher strontium concentrations. Scheelite II is associated with the economic gold mineralization and formed during re-crystallisation and re-precipitation of material which was partly re-mobilised from early scheelite I during infiltration of gold-bearing fluids. Early stage native gold inclusions are often associated with stage 2 sulphides, scheelite II and bismuth tellurides and contain Ag (3.6–24.4 wt.%), Hg (≤1.0 wt.%) and Bi (≤0.2 wt.%). Later stage electrum grains occur in association with stage 3 sulphides and sulphosalts and contain Hg (<0.8 wt.%) and elevated Sb concentrations (up to 3.0 wt.%). Noble gas isotope data (³He/⁴He: 0.2-0.4 Ra) for hydrothermal ore fluids trapped in the gold-related sulphides and sulphosalts (stage 2 pyrite and arsenopyrite; stage 3 pyrite, sphalerite, galena and lead sulphosalts) suggest that diverse fluid sources were involved in the formation of the Charmitan gold deposit. These data are indicative of a small, but significant input of fluids from external, deep-seated (mantle and possibly lower crust) sources. A decrease in the input of mantle helium and an increasing role of crustal helium from early to later stages of the mineralization is suggested by the measured ³He/⁴He and ⁴⁰Ar*/⁴He ratios. Sulphides from ore veins in meta-sedimentary rocks contain higher portions of meteoric fluids than those in intrusive rock types as indicated by their lower ³He/³⁶Ar ratios. The ³He/³⁶Ar ratios in the meta-sedimentary rocks agree well with ratios typical of gold mineralizations in the Tien Shan gold province completely hosted by meta-sedimentary sequences, indicating intense fluid-wall rock interaction.     

Isotopic composition (U/U) of some commonly used uranium reference materials

We have determined ²³⁸U/²³⁵U ratios for a suite of commonly used natural (CRM 112a, SRM 950a, and HU-1) and synthetic (IRMM 184 and CRM U500) uranium reference materials by thermal ionisation mass-spectrometry (TIMS) using the IRMM 3636 ²³³U-²³⁶U double spike to accurately correct for mass fractionation. Total uncertainty on the ²³⁸U/²³⁵U determinations is estimated to be <0.02% (2σ). These natural ²³⁸U/²³⁵U values are different from the widely used ‘consensus’ value (137.88), with each standard having lower ²³⁸U/²³⁵U values by up to 0.08%. The ²³⁸U/²³⁵U ratio determined for CRM U500 and IRMM 184 are within error of their certified values; however, the total uncertainty for CRM U500 is substantially reduced (from 0.1% to 0.02%). These reference materials are commonly used to assess mass-spectrometer performance and accuracy, calibrate isotope tracers employed in U, U-Th and U-Pb isotopic studies, and as a reference for terrestrial and meteoritic ²³⁸U/²³⁵U variations. These new ²³⁸U/²³⁵U values will thus provide greater accuracy and reduced uncertainty for a wide variety of isotopic determinations.     

The investment climate for climate investment: Joint Implementation in transition countries

Transition countries are expected to become important players in the emerging market for greenhouse gas emission reductions, as they can cut emissions at a relatively low cost. However, the attractiveness of the region as a supplier of emission reductions will not only depend on its cost advantage. It will also depend on the business climate offered to carbon investors—factors like a well-functioning legal and regulatory system, economic and political stability and the capacity to process emission reduction projects efficiently. This paper looks at the carbon investment climate in the transition countries eligible for Joint Implementation (JI)—Russia, Ukraine, Croatia and the EU accession countries. It concludes that JI investors will face a clear trade-off between the scope for cheap JI on the one hand, and the quality of the business environment and JI institutions on the other. The countries with the highest potential for cheap emission reductions also tend to be the countries with the most difficult business climate and the least institutional capacity for JI. The most attractive JI locations may be median countries with a reasonable JI potential and an acceptable business climate, such as Bulgaria, Romania and the Slovak Republic.     

Towards a better understanding of the Oulmes hydrogeological system (Mid-Atlas,Morocco)

Located in the Mid-Atlas (Morocco), the Oulmes plateau is famous for its mineral water springs “Sidi Ali” and “Lalla Haya” commercialised by the company “Les Eaux minérales d’Oulmès S.A”. Additionally, groundwater of the Oulmes plateau is intensively exploited for irrigation. The objective of this study, essentially performed from data collected during isotopic (summer 2004) and piezometric and hydrogeochemical field campaigns (spring 2007), is to improve the understanding of the Oulmes hydrogeological system. Analyses and interpretation of these data lead to the statement that this system is constituted by a main deep aquifer of large extension and by minor aquifers in a perched position. However, these aquifers interact enough to be in total equilibrium during the cold and wet period. As highlighted by isotopes, the origin of groundwater is mainly infiltration water except a small part of old groundwater with dissolved gas rising up from the granite through the schists.     

On the link between disc-galaxies and Damped Lyman-α systems

We model the chemical and spectrophotometric evolution of the Milky Way, spiral galaxies and Low Surface Brightness Galaxies in a consistent way. Some consequences with respect to the nature of Damped Lyman-α systems (DLAs) are investigated. This revised version was published online in September 2006 with corrections to the Cover Date.