Geochemistry of highly acidic mine water following disposal into a natural lake with carbonate bedrock

Acid mine drainage (AMD) from the Zn-Pb(-Ag-Bi-Cu) deposit of Cerro de Pasco (Central Peru) and waste water from a Cu-extraction plant has been discharged since 1981 into Lake Yanamate, a natural lake with carbonate bedrock. The lake has developed a highly acidic pH of similar to 1. Mean lake water chemistry was characterized by 16,775 mg/L acidity as CaCO(3), 4330 mg/L Fe and 29,250 mg/L SO(4). Mean trace element concentrations were 86.8 mg/L Cu, 493 mg/L Zn, 2.9 mg/L Pb and 48 mg/L As, which did not differ greatly from the discharged AMD. Most elements showed increasing concentrations from the surface to the lake bottom at a maximal depth of 41 m (e.g. from 3581 to 5433 mg/L Fe and 25,609 to 35,959 mg/L SO(4)). The variations in the H and 0 isotope compositions and the element concentrations within the upper 10 m of the water column suggest mixing with recently discharged AMD, shallow groundwater and precipitation waters. Below 15 m a stagnant zone had developed. Gypsum (saturation index, SI similar to 0.25) and anglesite (SI similar to 0.1) were in equilibrium with lake water. Jarosite was oversaturated (SI similar to 1.7) in the upper part of the water column, resulting in downward settling and re-dissolution in the lower part of the water column (SI similar to -0.7). Accordingly, jarosite was only found in sediments from less than 7 m water depth. At the lake bottom, a layer of gel-like material (similar to 90 wt.% water) of pH similar to 1 with a total organic C content of up to 4.40 wet wt.% originated from the kerosene discharge of the Cu-extraction plant and had contaminant element concentrations similar to the lake water. Below the organic layer followed a layer of gypsum with pH 1.5, which overlaid the dissolving carbonate sediments of pH 5.3-7. In these two layers the contaminant elements were enriched compared to lake water in the sequence As < Pb approximate to Cu < Cd < Zn = Mn with increasing depth. This sequence of enrichment was explained by the following processes: (i) adsorption of As on Fe-hydroxides coating plant roots at low pH (up to 3326 mg/kg As), (ii) adsorption at increasing pH near the gypsum/calcite boundary (up to 1812 mg/kg Pb, 2531 mg/kg Cu. and 36 mg/kg Cd), and (iii) precipitation of carbonates (up to 5177 mg/kg Zn and 810 mg/kg Mn: all data corrected to a wet base). The infiltration rate was approximately equal to the discharge rate, thus gypsum and hydroxide precipitation had not resulted in complete clogging of the lake bedrocks. (C) 2010 Elsevier Ltd. All rights reserved.

The trematodes and cestodes of Sorex araneus L. in Valaam Island (Ladoga Lake, USSR). 1

The trematode and the cestode fauna was examined in 50 specimens of common shrews Sorex araneus L. (Insectivora: Soricidae) cillected in Valaam Island, URSS during 1988 and 1989. Two species of Trematoda and seven species of Cestoda were identified; prevalence of infection was as follows: Brachulaemus fulvus (86% ), Rubenstrema exasperatum (4% ), Hymenolepis scutigera (54% ), Neoskrjabinolepis schaldybini (26% ), Vigisolepis spinulosa (4% ), Choanotaenia crassiscolex (86% ), Choanotaenia hepatica (6% ), Dilepis undula (2% ) and Polycercus sp. (2% ).

Compensatory β-cell mass expansion: a big role for a tiny actor.

Comment on: Jacovetti C, et al. J Clin Invest 2012; 122:3541-51.

Stability analysis of the 2007 Chehalis lake landslide based on long-range terrestrial photogrammetry and airborne LIDAR data

On December 4th 2007, a 3-Mm3 landslide occurred along the northwestern shore of Chehalis Lake. The initiation zone is located at the intersection of the main valley slope and the northern sidewall of a prominent gully. The slope failure caused a displacement wave that ran up to 38 m on the opposite shore of the lake. The landslide is temporally associated with a rain-on-snow meteorological event which is thought to have triggered it. This paper describes the Chehalis Lake landslide and presents a comparison of discontinuity orientation datasets obtained using three techniques: field measurements, terrestrial photogrammetric 3D models and an airborne LiDAR digital elevation model to describe the orientation and characteristics of the five discontinuity sets present. The discontinuity orientation data are used to perform kinematic, surface wedge limit equilibrium and three-dimensional distinct element analyses. The kinematic and surface wedge analyses suggest that the location of the slope failure (intersection of the valley slope and a gully wall) has facilitated the development of the unstable rock mass which initiated as a planar sliding failure. Results from the three-dimensional distinct element analyses suggest that the presence, orientation and high persistence of a discontinuity set dipping obliquely to the slope were critical to the development of the landslide and led to a failure mechanism dominated by planar sliding. The three-dimensional distinct element modelling also suggests that the presence of a steeply dipping discontinuity set striking perpendicular to the slope and associated with a fault exerted a significant control on the volume and extent of the failed rock mass but not on the overall stability of the slope.

Big data and other challenges in the quest for orthologs.

Given the rapid increase of species with a sequenced genome, the need to identify orthologous genes between them has emerged as a central bioinformatics task. Many different methods exist for orthology detection, which makes it difficult to decide which one to choose for a particular application. Here, we review the latest developments and issues in the orthology field, and summarize the most recent results reported at the third 'Quest for Orthologs' meeting. We focus on community efforts such as the adoption of reference proteomes, standard file formats and benchmarking. Progress in these areas is good, and they are already beneficial to both orthology consumers and providers. However, a major current issue is that the massive increase in complete proteomes poses computational challenges to many of the ortholog database providers, as most orthology inference algorithms scale at least quadratically with the number of proteomes. The Quest for Orthologs consortium is an open community with a number of working groups that join efforts to enhance various aspects of orthology analysis, such as defining standard formats and datasets, documenting community resources and benchmarking. AVAILABILITY AND IMPLEMENTATION: All such materials are available at http://questfororthologs.org. CONTACT: erik.sonnhammer@scilifelab.se or c.dessimoz@ucl.ac.uk.

Life histories and distribution of ostracods with depth in western Lake Geneva (Petit-Lac), Switzerland: A reconnaissance study

Because environmental conditions within a given basin are different for each season and at different water depth, knowledge of the life history and depth distribution of target species is important for environmental and palaeoenvironmental interpretations based on ostracod species assemblages and/or the geochemical compositions of their valves. In order to determine the distribution of species with depth as well as the life history of species from Lake Geneva, a one year sampling campaign of living ostracods was conducted at five sites (2, 5, 13, 33 and 70 m water depth) on a monthly basis in the Petit-Lac (western basin of Lake Geneva, Switzerland). Based on the results, the different species can be classified into three groups. Littoral taxa are found at 2 and 5 m water depth and include, in decreasing numbers of individuals, Cypridopsis vidua (O. F.Müller, 1776), Pseudocandona compressa (Koch, 1838), Limnocythere inopinata (Baird, 1843), Herpetocypris reptans (Baird, 1835), Potamocypris smaragdina (Vávra, 1891), Potamocypris similis (G. W. Müller, 1912), Plesiocypridopsis newtoni (Brady & Robertson, 1870), Prionocypris zenkeri (Chyzer & Toth, 1858) and Ilyocypris sp. Brady & Norman, 1889. Sublittoral species are found in a majority at 13 m water depth and to a lesser extend at 33 m water depth and include, in decreasing numbers of individuals, Fabaeformiscandona caudata (Kaufmann, 1900), Limnocytherina sanctipatricii, Candona candida (O. F. Müller, 1776) and Isocypris beauchampi (Paris, 1920). Profundal species are found equally at 13, 33 and 70 m water depth and includes, in decreasing numbers of individuals, Cytherissa lacustris (Sars, 1863), Candona neglecta Sars, 1887 and Cypria lacustris Lilljeborg, 1890. The occurrence of Limnocytherina sanctipatricii (Brady & Robertson, 1869) is restricted from late winter to late spring when temperatures are low, while C. vidua, L. inopinata, P. smaragdina, P. similis, P. newtoni and Ilyocypris sp. occur predominantly from spring to early autumn when temperatures are high. Individuals of C. neglecta, C. candida, F. caudata, P. compressa, C. lacustris, H. reptans and Cp. lacustris occur throughout the year with juveniles and adults occurring during the same period (C. neglecta at 70 m, C. lacustris at 13, 33 and 70 m, and H. reptans at 2, 5 and 13 m water depth) or with juveniles occurring during a different period of the year than adults (C. neglecta at 13 and 33 m and C. candida, F. caudata and P. compressa at their respective depth of occurrence). Among the environmental parameters investigated, an estimate of the relationship between ostracod autoecology and environmental parameters suggests that in the Petit-Lac: (i) water temperature and substrate characteristics are important factors controlling the distribution of species with depth, (ii) water temperature is also important for determining the timing of species development and, hence, its specific life history, and (iii) water oxygen and sedimentary organic matter content is less important compared to the other environmental parameter monitored.

Imaging molasse and quaternary sediments in Lake Geneva, Switzerland, with 3-D high-resolution seismic reflection methods: A case study

A high-resolution three-dimensional (3-D) seismic reflection survey was conducted in Lake Geneva, near the city of Lausanne, Switzerland, as part of a project for developing such seismic techniques. Using a single 48-channel streamer, the 3-D site with an area of 1200 m x 600 m was surveyed in 10 days. A variety of complex geologic structures (e.g. thrusts, folds, channel-fill) up to similar to150 m below the water bottom were obtained with a 15 in.(3) water gun. The 3-D data allowed the construction of an accurate velocity model and the distinction of five major seismic facies within the Lower Freshwater Molasse (Aquitanian) and the Quaternary sedimentary units. Additionally, the Plateau Molasse (PM) and Subalpine Molasse (SM) erosional surface, "La Paudeze" thrust fault (PM-SM boundary) and the thickness of Quaternary sediments were accurately delineated in 3-D.

Accounting for Big City Growth in Low Paid Occupations: Immigration and/or Service Class Consumption

Growth of 'global cities' in the 1980s was supposed to have involved an occupational polarisation, including growth of low paid service jobs. Though held to be untrue for European cities, at the time, some such growth did emerge in London a decade later than first reported for New York. The question is whether there was simply a delay before London conformed to the global city model, or whether another distinct cause was at work in both cases. This paper proposes that the critical factor in both cases was actually an upsurge of immigration from poor countries providing an elastic supply of cheap labour. This hypothesis and its counterpart based on growth in elite jobs are tested econometrically for the British case with regional data spanning 1975-2008, finding some support for both effects, but with immigration from poor countries as the crucial influence in late 1990s London. Keywords: regional labour markets; wages; employment; international migration; consumer demand JEL Codes: J21, J23, F22, R12

Diversity of biting midges of the genus Culicoides Latreille (Diptera: Ceratopogonidae) in the area of the Yacyretá Dam Lake between Argentina and Paraguay

The Culicoides communities have been analyzed between 1993/1998 in the area influenced by the Yacyretá Dam Lake (Paraná River, Argentina-Paraguay). Adults of Culicoides were collected monthly by using CDC light traps exposed for 24 h in 9 sampling sites located at both margins of the river; 21 species were recorded. Highest values of species richness were recorded during 1993/1994, being Quiteria and Corpus the sites with the higest number of species (10 and 11, respectively). The species diversity was elevated in Quiteria, Zaimán, Candelaria, Santa Tecla, Capitán Meza and Corpus (Shannon's diversity index 1.0-1.9) while Corateí, Ituzaingó and Aguapey showed less richness and diversity. The more abundant species were C. insignis, C. venezuelensis, C. leopoldoi, C. limai, C. flinti, C. debilipalpis, C. paraensis and C. guttatus. C. insignis, potential vector of bluetongue virus (BTV) to domestic and wild rumiants in the Neotropical region, is the predominant species in the area and was the only species widely distributed. C. paraensis, a proven vector of Oropouche virus to humans, is a common and abundant species. C. pusillus and C. lahillei, potential vectors of BTV and a filarial parasite, respectively, were occasionally collected. The taxonomic structure of communities was constant during the study period. The occasional species were not characteristic to one particular site and their presence could be related to non-intrinsic conditions.

Small changes, big benefits

Being overweight is a major health problem for Northern Ireland. This leaflet helps the public assess whether or not they are overweight and contains useful information on what to do about it, including identifying healthy options, setting targets, getting active and staying motivated.