Comment on "The Cosmic Time in Terms of the Redshift", by Carmeli et al

The time-redshift relation of Carmeli et al. differs from that of the standard flat LambdaCDM model by more than 500 million years for 1 < z < 4.5.Comment: 2 pages, to appear Found. Phys. Let

Potential impact of climate change on improved and unimproved water supplies in Africa

With significant climate change predicted in Africa over the next century, this chapter explores a key question: how will rural water supplies in Africa be affected? Approximately 550 million people in Africa live in rural communities and are reliant on water resources within walking distance of their community for drinking water. Less than half have access to improved sources (generally large diameter wells, springs, or boreholes equipped with handpumps); the majority rely on unimproved sources, such as open water and shallow wells. Major climate modelling uncertainties, combined with rapid socio-economic change, make predicting the future state of African water resources difficult; an appropriate response to climate change is to assume much greater uncertainty in climate and intensification of past climate variability. Based on this assumption the following should be considered: 1. Those relying on unimproved water sources (300 million in rural Africa) are likely to be most affected by climate change because unimproved sources often use highly vulnerable water resources. 2. Improved rural water supplies in Africa are overwhelmingly dependent on groundwater, due to the unreliability of other sources. 3. Climate change is unlikely to lead to continent-wide failure of improved rural water sources that access deeper groundwater (generally over 20 metres below ground surface) through boreholes or deep wells. This is because groundwater-based domestic supply requires little recharge, and the groundwater resources at depth will generally be of sufficient storage capacity to remain a secure water resource. However, a significant minority of people could be affected if the frequency and length of drought increases – particularly those in areas with limited groundwater storage. 4. In most areas, the key determinants of water security will continue to be driven by access to water rather than absolute water availability. Extending access, and ensuring that targeting and technology decisions are informed by an understanding of groundwater conditions, will become increasingly important. 5. Accelerating groundwater development for irrigation could increase food production, raise farm incomes and reduce overall vulnerability. However, ad hoc development could threaten domestic supplies and, in some areas, lead to groundwater depletion. Although climate change will undoubtedly be important in determining future water security, other drivers (such as population growth and rising food demands) are likely to provide greater pressure on rural water supplies

Fractures in shale: the significance of igneous intrusions for groundwater flow

Research in Cretaceous shales from West Africa has demonstrated that significant permeability can develop within shales at shallow depths (1 m day−1. Much of the variation in permeability is related to the degree of burial metamorphism, with shales that have been altered and that approach the anchizone having the highest permeability and those that are largely unaltered (early diagenetic zone) having the lowest permeability. However, further research targeting largely unaltered shales dominated by smectite clay has shown that the presence of small igneous intrusions can radically alter the hydrogeology. Twenty-four exploratory boreholes were drilled into smectite-dominated shale and nine of these boreholes were targeted to small dolerite intrusions within the shale. The dolerite was intensely fractured at the intrusion edge, with significant zeolite growth along the fracture surfaces. The permeability in the fractured dolerite was the highest measured in any shale borehole, with transmissivities of up to 60 m2 day−1 measured from pumping tests. Fracturing was less where dolerite was intruded into sandstones, however, and the measured transmissivity was lower (<0.5 m2 day−1). We postulate that the low permeability and high water content of the shale enabled high pressures to develop during intrusion, facilitating the development of fractures along the intrusion contact zone

Devonian plutons in southeastern Cape Breton Island, Nova Scotia

Four granitic plutons and a suite of granitic dykes of Devonian age occur in the Mira (Avalon) Terrane of southeastern Cape Breton Island. Granodiorite gradational to granite in the Lower St. Esprit pluton is chemically distinct from and unlikely to be genetically linked to comparable units in the other plutons. The Salmon River pluton consists of highly evolved rhyolite porphyry and is also not likely to be genetically linked to the other units. In contrast, the Gillis Mountain and Deep Cove plutons and.the Blue Mountain dykes are interpreted to be co-genetic and possibly co-magmatic on the basis of chemical continuity among their units, which range in composition from quartz monzodiorite to granite and rhyolite porphyry. They have I-type petrographic and chemical features, whereas the Lower St. Esprit has some M-type characteristics and the Salmon River rhyolite porphyry appears transitional between felsic I-type and A-type granites. Cu-Mo mineralization is associated with the Gillis Mountain pluton, and polymetallic Cu-Mo-Pb-Zn-Bi-Ag mineralization with greisen zones in the Deep Cove pluton and with skarn in the Blue Mountain contact metamorphic aureole. Minor Cu-Zn mineralization occurs adjacent to the Lower St. Esprit pluton, although a definite genetic relationship with thc pluton has not been established. Trace Pb mineralization has been reported from the Salmon River pluton. The origin of these Devonian plutons is uncertain, but is postulated to have been linked to regional strike-slip faulting and extension. R&#xC9;SUM&#xC9; Quatre plutons granitiques et une suite de dykes granitiques d'&#xE2;ge D&#xE9;vonien giseent dans le terrain de Mira (Avalon) du sud-est de l'ile-du-Cap-Breton. La granodiorite, en transition avec du granite, du pluton de Lower St-Esprit est chimiquement distincte et n'est probablement pas reli&#xE9;e g&#xE9;n&#xE9;tiquement aux unit&#xE9;s comparables des autres plutons. Le pluton de la rivi&#xE8;re Salmon consiste en une rhyolite porphyrique tr&#xE8;s &#xE9;volu&#xE9;e et n'est probablement pas reli&#xE9; g&#xE9;n&#xE9;tiquement aux autres unit&#xE9;s. En contraste, les plutons des monts Gillis et de l'anse Deep ainsi que les dykes du mont Blue sont interpr&#xE9;t&#xE9;s comme &#xE9;tant cog&#xE9;n&#xE9;tiques et possiblement comagmatiques, sur la base de la continuit&#xE9; chimique entre leurs unit&#xE9;s, qui vont des monzodiorites quartzif&#xE8;res aux granites et aux rhyolites porphyriques. Ces roches intrusives ont des caract&#xE9;ristiques p&#xE9;trographiques et chimiques de granites de type I tandis que le pluton de Lower St-Esprii a quelqucs caract&#xE9;ristiques de type M et que la rhyolite porphyrique de la rivi&#xE8;re Salmon semble &#xEA;tre transitionnelle entre les granites felsiques de type I et ceux de type A. De la min&#xE9;ralisation en Cu-Mo est associ&#xE9;e au pluton du mont Gillis, de la min&#xE9;ralisation polym&#xE9;tallique en Cu-Mo-Pb-Zn-Bi-Ag avec des zones de greisen se retrouv&#xE9; dans le pluton de l'anse Deep et il y a des skarns dans l'aurdole m&#xE9;tamorphique du mont Blue. Il y a des occurences mineures de min&#xE9;ralisation en Cu-Zn pr&#xE8;s du pluton de Lower St-Esprit bien qu'un lien g&#xE9;nctique d&#xE9;finitif avec le pluton n'ait pas &#xE9;t&#xE9; &#xE9;tabli. Des traces de min&#xE9;ralisation en Pb sont mentionn&#xE9;es pour le pluton de la rivi&#xE8;re Salmon. L'origine de ces plutons d&#xE9;voniens est incertaine mais on suppose qu'elle est reli&#xE9;e aux failles de d&#xE9;crochement et d'extension r&#xE9;gionales. [Traduit par le journal

Geological setting and depositional environment of the Stirling Group of southeastern Cape Breton Island, Nova Scotia

The Stirling Group consists of ca. 680 Ma volcanic and volcaniclastic rocks, interpreted to have been deposited in and around a trough flanked by felsic volcanic centres. The volcaniclastic rocks are dominated by lapilli tuff and tuffaceous litharenite sequences. The lapilli tuffs show some evidence of subaqueous reworking but most may have originated as air-fall deposits. Sedimentary structures in the litharenites suggest subaqueous mass transport into the trough and deposition below wave base. Pyritic siltstone-chert-carbonate laminites, which are locally associated with the litharenites along the southeastern side of the trough adjacent to felsic volcanic centres, probably represent a mixture of fine-grained distal turbidites and chemical precipitates from subaqueous volcanic exhalations. The volcanic rocks of the Stirling Group do not show convincing evidence for subaqueous deposition: the felsic rocks appear to form subvolcanic intrusions and domes flanked by felsic crystal-rich lapilli tuff and rare welded(?) tuff; the mafic volcanic rocks are not pillowed but are closely associated with breccias which may have formed partly by quench fragmentation. The overall facies assemblage and its association with VMS Zn-Pb-Cu-Ag-Au mineralization are compatible with generation in an intra-arc basin. As the Stirling Group is significantly older than the volcanic belts which flank it, it may represent a tectonically displaced remnant of a pre-existing arc. R&#xC9;SUM&#xC9; Le Groupe de Stirling consiste en roches volcaniques et volcanoclastiques d'environ 680 Ma, interpr&#xE9;t&#xE9;es comme ayant &#xE9;t&#xE9; d&#xE9;pos&#xE9;es &#xE0; l'int&#xE9;rieur et autour d'une fosse bord&#xE9;e de centres volcaniques felsiques. Les roches volcanoclastiques sont domin&#xE9;es par des s&#xE9;equences de tufs &#xE0; lapilli et de lithar&#xE9;nites tuffac&#xE9;es. Les tufs &#xE0; lapilli montrent quelques &#xE9;vidences de remaniement subaqueux mais la plupart pourraient &#xEA;tre des d&#xE9;p&#xF4;ts de retomb&#xE9;es a&#xE9;riennes. Les structures s&#xE9;dimentaires dans les lithar&#xE9;nites suggerent des mouvements de masse subaqueux dans la fosse et une d&#xE9;position sous la base des vagues. Des laminites de siltstone pyriteux, chert et carbonates, qui sont localement associees aux litharenites le long du flanc sud-est de la fosse I proximite des centres volcaniques felsiques, repr&#xE9;sentent probablement un melange de turbidites distales &#xE0; grain fin et de pr&#xE9;cipit&#xE9;s chimiques provenant d'exhalaisons volcaniques sous-marines. Les roches volcaniques du Groupe de Stirling ne montrent pas d'evidences convaincantes de d&#xE9;p&#xF4;t sous-marin: les roches felsiques semblent former des intrusions subvolcaniques et des domes bord&#xE9;s de tufs &#xE0; lapilli felsiques riches en cristaux et de rares tufs soud&#xE9;s (?); les roches volcaniques mafiques ne sont pas coussinees mais sont etroitement associ&#xE9;es &#xE0; des br&#xE8;ches qui ont pu en partie se former par fragmentation relive &#xE0; la trempe. L'assemblage g&#xE9;n&#xE9;ral de faci&#xE8;s et son association avec de la min&#xE9;ralisation en sulfures massifs volcanogenes de Zn-Pb-Cu-Ag-Au sont compatibles avec une formation dans un bassin intra-arc. Comme le Groupe de Stirling est nettement plus ancien que les ceintures volcaniques qui le bordent, il pourrait repr&#xE9;senter un vestige d'un arc pr&#xE9;existant d&#xE9;plac&#xE9; tectoniquement. [Traduit par la r&#xE9;daction

Investigating the productivity and sustainability of weathered basement aquifers in tropical Africa using numerical simulation and global sensitivity analysis

Groundwater stored in weathered basement aquifers (WBAs) is a strategic water resource. In this study, we investigate the productivity of WBAs and sustainability of groundwater abstractions using a novel process‐based stochastic modeling approach, which is applied to simulate abstractions in the Precambrian basement aquifer in Ghana. The statistical distribution of the generated synthetic yield data was found in very good agreement with observed yield data from the same Ghanaian aquifer. Further analysis provided robust insights regarding how different hydrogeological parameters of the WBA, and their interplay, control aquifer productivity and sustainability. Results indicate that 97% of the simulated abstractions could sustain the yield of a hand pump (6 L/min), approximately 30% could also sustain yields >60 L/min, while only 1% could sustain yields greater than 300 L/min. The model indicates that an aquifer transmissivity value of approximately 1.4 m2/day is required for a successful hand‐pumped borehole, while a higher yielding source (60 L/min) requires a transmissivity value of at least 9.5 m2/day. A global sensitivity analysis of 13 model input parameters shows that the thickness of the regolith and the maximum hydraulic conductivity developed at the base of the saprolite are the critical factors controlling success and sustainability for low yielding hand‐pumped boreholes. For higher yielding supplies, the net recharge, the depth to groundwater, and the aquifer extent become increasingly significant. Results from this work have important implications for the potential for increased development of groundwater from WBAs in tropical Africa

Baseline Scotland : an overview of available groundwater chemistry data for Scotland

This report forms a national overview of existing groundwater chemistry data for Scotland, carried out to provide a foundation for the new project Baseline Scotland. This project is jointly funded by the British Geological Survey (BGS) and the Scottish Environment Protection Agency (SEPA), and aims to improve data availability and understanding of the chemistry of Scotland’s groundwater. Understanding baseline groundwater chemistry is fundamental to helping to implement the Water Framework Directive: it is difficult to determine whether groundwater is polluted unless the baseline is known. Also, the presence or absence of various elements in water can occasionally give rise to health concerns or make the water unacceptable for human use. Chemistry data from Scottish groundwater samples collected prior to the start of the Baseline Scotland project in June 2004 have been collated and described. Many of the data came from previous BGS studies, but data were also available from Scottish Water, councils and SEPA. In total, more than 800 groundwater chemistry analyses were identified. The data are of variable quality and were subject to a thorough quality-assurance assessment. This involved gathering additional information on sources, checking the units for consistency, removing data from highly contaminated sites and calculating ionic balances. After this process the final dataset was as follows: • The dataset comprised 428 sites with full major ion chemistry with an error in ionic balance of less than 10%; • Of these 428 sites, 31 sites had a wellhead measurement of dissolved oxygen, and 103 had a wellhead measurement of the redox potential; • Information on trace elements was generally limited. Only iron and manganese had more than 200 measurements across Scotland. For arsenic and fluoride (two trace elements generally considered the greatest risk for health in groundwater) data are particularly limited: 65 meaningful measurements for arsenic, and 149 for fluoride. The quality of the data is also variable – samples from Scottish Water and SEPA are generally not filtered at the sample site. The dataset is highly skewed, with most good quality data being available for the Devonian aquifer in Fife and parts of Morayshire, and the Permian aquifer in Dumfries. There are few data available for Precambrian or Silurian/Ordovician rocks. The major ion data were used to characterise Scottish groundwaters. Summary statistics have been calculated and the data presented on box plots, cumulative frequency plots and tri-linear diagrams. The data illustrate the variability of Scottish groundwater, reflecting the diverse geology and local environmental conditions. • The most highly mineralised groundwater is found within the Carboniferous rocks. There is a marked bimodal distribution for chloride and sodium which may indicate mixing with formation water. Sulphate concentrations are considerably higher than for other aquifers which may reflect the oxidisation of sulphide minerals within mudstones and legacy of coal mining. • Groundwaters from the Permian sedimentary aquifers in Scotland have well-defined chemistry and the least variation in concentrations of major ions of all Scottish groundwaters. Groundwater is of Ca-Mg-HCO3 type with a narrow range in Mg/Ca ratio, and near-neutral pH. Most data are available for the Devonian aquifers in Scotland. Groundwaters tend to be of Ca-HCO3 to Ca-Mg-HCO3 type and show a wider range in Mg/Ca ratio than for the Permian rocks, but similar bicarbonate concentrations (median Devonian HCO3 178 mg/l, median Permian HCO3 157 mg/l). Median pH from the Devonian groundwaters is 7.5. • The available data for the superficial deposits, Precambrian rocks and Silurian/Ordovician rocks indicate similar variability of major ion chemistry across the three hydrogeological environments. This may reflect the short residence time of much of the water, and the high proportion of samples from springs and shallow wells. The waters have typically low mineralization and pH less than 7. • Groundwaters in volcanic aquifers are generally of Ca-HCO3 type, and similar to the sandstone aquifers, with the exception of potassium which varies considerably across the volcanic aquifers. A small proportion of samples have chloride, sodium, sulphate and calcium concentrations. • Most of the small island sources have high chloride concentrations, probably as a result of increased chloride concentrations in recharge. Other notable elevated chloride concentrations are observed in the coastal areas of East Lothian, Arbroath, Morayshire and northwest Fife The majority of inland sources have chloride concentrations less than 25 mg/l, and in upland areas concentrations are less than 10 mg/l. • Nitrate data indicate a clear pattern across Scotland, with concentrations in excess of 25 mg/l as NO3 across the east and southwest. Concentrations over much of the rest of Scotland are less than 10 mg/l as NO3. The elevated concentrations of nitrate largely coincide with the agricultural areas of Scotland and are attributable to fertiliser applications and the presence of intensive farming; this is consistent with other recent studies. There are insufficient reliable data to identify clear trends in the concentration of trace elements in Scottish groundwater. However, the following have been highlighted from the existing data. • Iron and manganese concentrations greater than the EC maximum permissible value are observed in all hydrogeological units in Scotland. Iron and manganese are ubiquitous in rocks and the dominant controls on their presence in groundwater are the pH and redox status. • The limited data for aluminium indicate that concentrations approach or exceed the EC maximum permissible value for drinking water in Precambrian and volcanic rocks and granite. This is linked to the acidic conditions of groundwater in these environments. • The available data indicate that natural chromium concentrations in Scottish groundwater are typically well below the EC maximum permissible value, and usually below detection limit. There are no data from the Glasgow area, where elevated chromium concentrations may be expected due to widespread contamination from the chrome and steel industry. • Fluoride concentrations greater than 0.5 mg/l have been measured in samples from the Permo-Triassic sandstone in Morayshire and the Permo-Triassic sandstone in Mauchline, southwest Scotland. There are several isolated samples scattered throughout Scotland with fluoride concentrations greater than the EC maximum permissible value of 1.5 mg/l. In conclusion, there is a lack of systematically collected groundwater quality data for Scotland. Particularly lacking are data on trace elements and pH and redox status. The following recommendations should be implemented to give a reliable national dataset. 1. New data are required that are collected in a consistent, reliable and systematic manner, and analysed to a consistent degree of accuracy. There is not widespread coverage of groundwater chemistry data in Scotland. Certain hydrogeological units have few reliable data and should be targeted for further sampling. 3. Wellhead measurements of redox potential and dissolved oxygen are required in order to understand the groundwater geochemical processes and element distributions. 4. There is evidence that the sampled chemistry is affected by the type of water source (e.g. well, borehole or spring). It is essential that comprehensive data are collected on each sampled source. 5. Routine sampling for age dating would be helpful for understanding residence times of groundwater and interpreting chemical variations – particularly nitrate data. 6. There are insufficient data on many trace elements in Scotland to characterise their occurrence or understand their origin. Comprehensive analysis of groundwater chemistry, including trace elements, should be carried out wherever possible

Point mutations of human interleukin-1 with decreased receptor binding affinity

AbstractInterleukin-1 (IL-1) is a monocyte-derived polypeptide hormone that interacts with a plasma membrane receptor. We have used oligonucleotide-directed mutagenesis to construct mutant human IL-1 proteins. Three different point mutants in a unique histidine residue (position 30) exhibited varying degrees of reduced IL-1 receptor binding affinity, whereas point mutants at five other residues behaved normally. Structural analysis of these mutant proteins by nuclear magnetic resonance spectroscopy detected no (or only minor) conformational changes relative to wild-type IL-1. These data suggest that the unique histidine residue influ- ences the architecture of the receptor binding site on human IL-1

Land cover influence on catchment scale subsurface water storage investigated by multiple methods:Implications for UK Natural Flood Management

Study region: United Kingdom (UK). Study Focus: ‘Natural flood management’ (NFM) schemes manipulating land use and other catchment features to control runoff are increasingly promoted across the UK. Catchment water storage and mixing processes influence runoff, but our understanding of the effects of land cover change on these processes is still limited. This study combined hydrometric, isotopic and geochemical measurements to investigate land cover versus potential topographic, soil and geological controls. It compared storage-discharge dynamics in nine nested catchments within a 67 km2 managed upland catchment in southern Scotland. Storage and mixing dynamics were characterised from hydrometric data using recession analysis and from isotopic data using mean transit time and young water fraction estimates. To give information on water sources, groundwater fraction was estimated from end member mixing analysis based on acid neutralising capacity.New hydrological insights: The analysis showed low but variable sub-catchment scale dynamic storage (16–200 mm), mean transit times (134–370 days) and groundwater fractions (0.20–0.52 of annual stream runoff). Soil hydraulic conductivity was most significantly positively correlated with storage and mixing measures, whilst percentage forest cover was inversely correlated. Any effects of forest cover on increasing catchment infiltration and storage are masked by soil hydraulic properties even in the most responsive catchments. This highlights the importance of understanding dominant controls on catchment storage when using tree planting as a flood management strategy