Climate Change and Cryptosporidiosis: A Qualitative Analysis

The effects of climate change on drinking-waterborne cryptosporidiosis transmission in the United States are analyzed using an influence diagram representation of epidemic development. Results from a systematic qualitative analysis indicate that climate change will have little effect on cryptosporidiosis incidence if the United States continues to be wealthy and maintains its commitment to public health. The major impact will, instead, be the additional costs of adapting to new climate regimes in order to avoid drinking-waterborne disease risk. These costs, for the most part, will be from improved monitoring and treatment of drinking water. The consequences of disaster scenarios are also considered. These, too, suggest that climate change per se will be a poor predictor of waterborne cryptosporidiosis in countries with high standards of living. Rather, the risk of epidemics will depend on the interplay between population, public health investment, infrastructure maintenance, emergency planning/response capabilities, water-treatment technologies, drinking-water regulations, and climate.     

Parametric study of near-wake structure of spherical and cylindrical bodies in the laboratory

Some aspects of the interaction between metal bodies and streaming rarefied plasmas were studied in a newly constructed Plasma Wind Tunnel as part of an attempt to investigate (via simulation) phenomena relevant to the spacecraft/space plasma interaction. Detailed near-wake ion current profiles for both spherical and cylindrical bodies at different body potentials (φ_S) and at different plasma flow parameters are presented. Various features of the profiles can be correlated, at least qualitatively, with both plasma and body characteristics. For example, the width of the wake zone appears proportional to the Debye length (λ_D) and depends on the potential of the target body although it appears to be relatively insensitive to the ratio $\text{S = V}{}_{\mathrm{<mtext>flow</mtext>}}\text{/(}\text{2kT}{}_{\mathrm{e}}\text{M}{}_{\mathrm{+}}\text{)}{}^{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$. The amplitude of the ion current peak(s) also appears proportional to λ_D while, for fixed φ_S, the location of the peak is directly related to S and possibly dependent upon body geometry. The general importance of body geometry is qualitatively demonstrated. In addition, a discussion of the relevance of the above studies to previous in situ data obtained from the Ariel I and Gemini/Agena missions is given.     

Management of coral reefs: we have gone wrong when neglecting active reef restoration

The current best management tools employed in coral reefs worldwide do not achieve conservation objectives as coral reefs continue to degrade. Even improved reef management helps, at best, to reduce the degradation pace, whereas the worsening global changes foretell a dismal fate for coral reefs. The assertion made here is that the prospect for reefs' future is centered on omnipresent acceptance of restoration, an 'active' management instrument. A recent promising such tool is the 'gardening concept', influenced by the well-established scientific discipline of terrestrial forestation. This notion is supported by a two-step protocol. The first step entails rearing coral "seedlings", in specially designed underwater nurseries, to transplantable size, before applying the second step, out-planting into damaged areas of the nursery-farmed coral colonies. Only the establishment of large-scale nurseries and transplantation actions, together with conventional management tools, will be able to cope with extensive reef degradation on the global scale.     

Lacustrine sediments and lichen transplants: two contrasting and complimentary environmental archives of natural and anthropogenic lead in the South Urals, Russia

Lead (Pb) concentrations and isotope ratios of two different geochemical archives are compared; lake sediment cores and lichens (Hypogymnia physodes, naturally growing and transplanted) from a ca. 80 km-long transect centred on the Cu smelter and former mining town of Karabash, Ural Mountains, Russia. Lead concentrations in sediment cores from 10 lakes were generally low near their base and show an abrupt increase in their upper portions interpreted to coincide with the onset of large-scale smelting operations in 1910. Lead isotope ratios derived from ²⁰⁴Pb, ²⁰⁶Pb, ²⁰⁷Pb, ²⁰⁸Pb of the bottom layers differed significantly from those of the top. The top sediments have isotope ratios that show distinct end members, one of which was the stack dust from the Karabash smelter, which is similar to the Pb derived from ores from Sibay, a major mine in the Urals. The composition of the bottom sediment layers generally fall slightly off a mixing line between the top sediments and average Earth’s upper crust. Lichens transplanted from a reference site, as well as naturally growing lichens, sampled from southwest of the smelter have isotope ratios similar to those of the stack dust. Lichens to the northeast contained Pb from the smelter, but are increasingly influenced by other sources probably leaded petrol and local soils, and a signature derived from a source enriched in ²⁰⁷Pb. Vegetables collected from local kitchen gardens contained Pb from an additional atmospheric source, possibly coal. Our work confirms that: (1) Pb isotopes in lake sediments provide a long-term record of inputs and allows the characterisation of natural and anthropogenic sources; (2) Pb isotopes in lichens provide a short-term record of local and long-range atmospheric deposition at high spatial resolution and short time scales as they replace their Pb content within a few months; (3) determination of all four stable Pb isotopes is necessary for the identification of the sources of Pb and is extremely sensitive for discerning minor source signatures, even in an area with a dominant source such as a smelter. Particularly significant for the Karabash area is that ore-smelter-derived airborne Pb is a major component in the lake sediments and lichens but its contribution reaches insignificant levels ca. 40 km from the smelter.     

The contribution of moisture to heat stress in a period of global warming: the case of the Mediterranean

This study deals with potential changes in the relative humidity associated with global warming and their implications on heat stress along the coastal region of the Mediterranean in the summer season. It is based on the assumption that the regional warming will enhance the lower-level stability due to the thermal inertia of the sea with respect to its overlying air. The enhanced stability implies more effective trapping of the near surface moisture, and as a result—further increase of the relative humidity. The marine boundary layer over the Mediterranean is modeled. The central feature of the model is the marine inversion capping the marine moist air, which intensity is positively correlated with the stability. Simple calculations indicate that if the temperature increases, while the stability remains unchanged, the near-surface relative humidity would not be affected. But, an increase in the stability would result in an increase in the near-surface relative humidity. This prediction is validated through observed trends of the respective fields, using the NCEP/NCAR reanalysis data and soundings from the eastern Mediterranean. The results are consistent in indicating an increase in the near-surface temperature, the lower-level stability and the relative humidity over the eastern part of the Mediterranean, but not in its western part. The results for the eastern Mediterranean support the expectation for an aggravation of heat stress beyond that imparted by the temperature rise.     

Formation of sequential basins along a strike–slip fault–Geophysical observations from the Dead Sea basin

The Dead Sea basin is often cited as one of the classic examples for the evolution of pull-apart basins along strike–slip faults. Despite its significance, the internal structure of the northern Dead Sea basin has never been addressed conclusively. In order to produce the first comprehensive, high-resolution analysis of this area, all available seismic data from the northern Dead Sea (lake)–lower Jordan valley (land) were combined. Results show that the northern Dead Sea basin is comprised of a system of tectonically controlled sub-basins delimited by the converging Western and Eastern boundary faults of the Dead Sea fault valley. These sub-basins grow shallower and smaller to the north and are separated by structural saddles marking the location of active transverse faults. The sedimentary fill within the sub-basins was found to be relatively thicker than previously interpreted. As a result of the findings of this study, the “classic” model for the development of pull-aparts, based on the Dead Sea, is revised. The new comprehensive compilation of data produced here for the first time was used to improve upon existing conceptual models and may advance the understanding of similar basinal systems elsewhere.     

Global climate change and the effect of conservation practices in US agriculture

 Increase in the use of conservation practices by agriculture in the United States will enhance soil organic carbon and potentially increase carbon sequestration. This, in turn, will decrease the net emission of carbon dioxide. A number of studies exist that calibrate the contribution of various individual, site-specific conservation practices on changes in soil organic carbon. There is a general absence, however, of a comprehensive effort to measure objectively the contribution of these practices including conservation tillage, the Conservation Reserve Program, and conservation buffer strips to an change in soil organic carbon. This paper fills that void. After recounting the evolution of the use of the various conservation practices, it is estimated that organic carbon in the soil in 1998 in the United States attributable to these practices was about 12.2 million metric tons. By 2008, there will be an increase of about 25%. Given that there is a significant potential for conservation practices, which could lead to an increase in carbon sequestration, there are a number of policy options that can be pursued. These include education and technical assistance, financial assistance, research and development, land retirement, and regulation and taxes. Received: 27 December 1999 · Accepted: 14 March 2000     

Stable isotope and Sr2+/Ca2+ evidence of diagenetic dedolomitization in a schizohaline environment: Cenomanian of northern Israel

The Cenomanian—Turonian Upper Judea Group of Israel comprises shallow-marine hypersaline dolomites passing laterally into ‘basinal’ limestones and chalks. Chertbearing diagenetic dedolomites characterize the transitional zone. The restriction of dedolomites to a narrow zone, their light δ¹³C (up to ?11%), and their low Sr²⁺ concentration (<16 ppm) all suggest that the dedolomites were formed diagenetically through exposure of this zone to fresh meteoric waters. This type of partly changing environments was referred to as schizohaline by Folk and Siedlecka (1974).     

Optical photometry using Bradford robotic telescope

The Bradford Robotic Telescope (BRT) is located on Mount Teide at Tenerife and is working, taking observations since 2003. It is a fully automated telescope. The hardware and software used for the working of the telescope are described here. Twenty four BL Lac objects are observed since 2005 and magnitudes of the objects are calculated. We describe in this paper the working of BRT and optical BVR photometry of BL Lac objects, observed during 2005–2007.