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https://www.readbyqxmd.com/read/28107961/new-approach-of-a-transient-icp-ms-measurement-method-for-samples-with-high-salinity
#1
Christina Hein, Jonas Michael Sander, Ralf Kautenburger
In the near future it is necessary to establish a disposal for high level nuclear waste (HLW) in deep and stable geological formations. In Germany typical host rocks are salt or claystone. Suitable clay formations exist in the south and in the north of Germany. The geochemical conditions of these clay formations show a strong difference. In the northern ionic strengths of the pore water up to 5M are observed. The determination of parameters like Kd values during sorption experiments of metal ions like uranium or europium as homologues for trivalent actinides onto clay stones are very important for long term safety analysis...
March 1, 2017: Talanta
https://www.readbyqxmd.com/read/28107398/integrated-chronology-flora-and-faunas-and-paleoecology-of-the-alajuela-formation-late-miocene-of-panama
#2
Bruce J MacFadden, Douglas S Jones, Nathan A Jud, Jorge W Moreno-Bernal, Gary S Morgan, Roger W Portell, Victor J Perez, Sean M Moran, Aaron R Wood
The late Miocene was an important time to understand the geological, climatic, and biotic evolution of the ancient New World tropics and the context for the Great American Biotic Interchange (GABI). Despite this importance, upper Miocene deposits containing diverse faunas and floras and their associated geological context are rare in Central America. We present an integrated study of the geological and paleontological context and age of a new locality from Lago Alajuela in northern Panama (Caribbean side) containing late Miocene marine and terrestrial fossils (plants, invertebrates, and vertebrates) from the Alajuela Formation...
2017: PloS One
https://www.readbyqxmd.com/read/28107034/automated-measurement-of-magnesium-calcium-ratios-in-gastropod-shells-using-laser-induced-breakdown-spectroscopy-for-paleoclimatic-applications
#3
Adolfo Cobo, Asier García-Escárzaga, Igor Gutiérrez-Zugasti, Jesús Setién, Manuel R González-Morales, José Miguel López-Higuera
The chemical composition of mollusk shells offers information about environmental conditions present during the lifespan of the organism. Shells found in geological deposits and in many archeological sites can help to reconstruct past climatic conditions. For example, a correlation has been found between seawater temperature and the amount of some substituent elements (e.g., magnesium, strontium) in the biogenerated calcium carbonate matrix of the shell, although it is very species-specific. Here we propose the use laser-induced breakdown spectroscopy (LIBS) to estimate Mg/Ca ratios in modern specimens of the common limpet Patella vulgata...
January 1, 2017: Applied Spectroscopy
https://www.readbyqxmd.com/read/28105721/bioarchaeology-in-the-ancient-near-east-challenges-and-future-directions-for-the-southern-levant
#4
Susan Guise Sheridan
The synthesis of biological anthropology, archaeology, and social theory provides a bioarchaeological model to reconstruct nuanced aspects of demography, diet, disease, death, daily activities, and biodistance, even in the absence of discrete burials. Numerous skeletal assemblages in the southern Levant are composed of mixed and fragmented bones resulting from generational use of cemeteries, mass burial, and additional communal burial practices. Others become commingled due to taphonomic processes such as flooding, geological events, or human mediated mechanisms like looting, improper excavation, and poor curation...
January 2017: American Journal of Physical Anthropology
https://www.readbyqxmd.com/read/28103105/evolution-of-earth-like-extrasolar-planetary-atmospheres-assessing-the-atmospheres-and-biospheres-of-early-earth-analog-planets-with-a-coupled-atmosphere-biogeochemical-model
#5
S Gebauer, J L Grenfell, J W Stock, R Lehmann, M Godolt, P von Paris, H Rauer
Understanding the evolution of Earth and potentially habitable Earth-like worlds is essential to fathom our origin in the Universe. The search for Earth-like planets in the habitable zone and investigation of their atmospheres with climate and photochemical models is a central focus in exoplanetary science. Taking the evolution of Earth as a reference for Earth-like planets, a central scientific goal is to understand what the interactions were between atmosphere, geology, and biology on early Earth. The Great Oxidation Event in Earth's history was certainly caused by their interplay, but the origin and controlling processes of this occurrence are not well understood, the study of which will require interdisciplinary, coupled models...
January 2017: Astrobiology
https://www.readbyqxmd.com/read/28096389/ontogenetic-and-life-history-trait-changes-associated-with-convergent-ecological-specializations-in-extinct-ungulate-mammals
#6
Helder Gomes Rodrigues, Anthony Herrel, Guillaume Billet
Investigating life history traits in mammals is crucial to understand their survival in changing environments. However, these parameters are hard to estimate in a macroevolutionary context. Here we show that the use of dental ontogenetic parameters can provide clues to better understand the adaptive nature of phenotypic traits in extinct species such as South American notoungulates. This recently extinct order of mammals evolved in a context of important geological, climatic, and environmental variations. Interestingly, notoungulates were mostly herbivorous and acquired high-crowned teeth very early in their evolutionary history...
January 17, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28095467/phylogenetically-widespread-polyembryony-in-cyclostome-bryozoans-and-the-protracted-asynchronous-release-of-clonal-brood-mates
#7
Helen L Jenkins, Andrea Waeschenbach, Beth Okamura, Roger N Hughes, John D D Bishop
Polyembryony-the production of multiple cloned embryos from a single fertilised egg-is a seemingly paradoxical combination of reproductive modes that nevertheless persists in diverse taxa. We document features of polyembryony in the Cyclostomata (Bryozoa)-an ancient order of modular colonial marine invertebrates-that suggest a substantial reduction in the paradoxical nature of this enigmatic reproductive mode. Firstly, we provide molecular evidence for polyembryony in three exemplar species, supporting the widely cited inference that polyembryony characterises the entire order...
2017: PloS One
https://www.readbyqxmd.com/read/28091595/geological-support-for-the-umbrella-effect-as-a-link-between-geomagnetic-field-and-climate
#8
Ikuko Kitaba, Masayuki Hyodo, Takeshi Nakagawa, Shigehiro Katoh, David L Dettman, Hiroshi Sato
The weakening of the geomagnetic field causes an increase in galactic cosmic ray (GCR) flux. Some researchers argue that enhanced GCR flux might lead to a climatic cooling by increasing low cloud formation, which enhances albedo (umbrella effect). Recent studies have reported geological evidence for a link between weakened geomagnetic field and climatic cooling. However, more work is needed on the mechanism of this link, including whether the umbrella effect is playing a central role. In this research, we present new geological evidence that GCR flux change had a greater impact on continental climate than on oceanic climate...
January 16, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28089160/investigation-of-hexavalent-chromium-sorption-in-serpentine-sediments
#9
Thanasis Mpouras, Maria Chrysochoou, Dimitris Dermatas
In this study the removal of hexavalent chromium (Cr(6+)) by serpentine sediments was investigated in order to delineate Cr(6+) sorption behavior in aquifers with ultramafic geologic background. Batch experiments were conducted in order to determine the influence of several parameters on Cr(6+) removal, including the pH of the sediment solution, mineralogy, sediment's particle size and Cr(6+) initial concentration. The results showed that Cr(6+) removal was due to both adsorption and reduction phenomena. Reduction was attributed to the presence of a magnetic fraction in the sediment, mostly related to magnetite, which contributed almost 50% of the total removal in the pH range 3-7...
January 5, 2017: Journal of Contaminant Hydrology
https://www.readbyqxmd.com/read/28088705/ultrasonic-compaction-of-granular-geological-materials
#10
Andrew Feeney, Sakalima Sikaneta, Patrick Harkness, Margaret Lucas
It has been shown that the compaction of granular materials for applications such as pharmaceutical tableting and plastic moulding can be enhanced by ultrasonic vibration of the compaction die. Ultrasonic vibrations can reduce the compaction pressure and increase particle fusion, leading to higher strength products. In this paper, the potential benefits of ultrasonics in the compaction of geological granular materials in downhole applications are explored, to gain insight into the effects of ultrasonic vibrations on compaction of different materials commonly encountered in sub-sea drilling...
January 5, 2017: Ultrasonics
https://www.readbyqxmd.com/read/28087527/floc-formation-reduces-the-ph-stress-experienced-by-microorganisms-living-in-alkaline-environments
#11
C J Charles, S P Rout, K A Patel, S Akbar, A P Laws, B R Jackson, S A Boxall, P N Humphreys
: The survival of microorganisms within a cementitious geological disposal facility for radioactive wastes is heavily dependent on their ability to survive the calcium dominated, hyper-alkaline conditions resulting from the dissolution of the cementitious materials. The present study shows that the formation of flocs, composed of a complex mixture of extracellular polymeric substances (EPS), provides protection against alkaline pH values up to pH 13.0. The flocs were dominated by Alishewanella and Dietzia sp, producing a mannose rich carbohydrate fraction incorporating extracellular DNA, resulting in Ca(2+) sequestration...
January 13, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28081578/birth-prevalence-of-anorectal-malformations-for-the-western-cape-province-south-africa-2005-to-2012
#12
Andre Theron, Alp Numanoglu
Introduction Anorectal malformations (ARMs) are a major birth anomaly worldwide. South Africa has ethnically and geologically diverse populations. A recent publication indicated an increased birth prevalence of ARMs in the Witwatersrand referral area between 2005 and 2010. The purpose of this study was to determine the birth prevalence of ARM and its various subtypes in the Western Cape referral district over an 8-year period. Methods For an 8-year period from January 1, 2005, to December 31, 2012; retrospective data were collected from the Pediatric Surgical Departments of Red Cross War Memorial Children's Hospital, Tygerberg Children's Hospital, as well as the private sector health registries...
January 12, 2017: European Journal of Pediatric Surgery
https://www.readbyqxmd.com/read/28079121/local-geology-controlled-the-feasibility-of-vitrifying-iron-age-buildings
#13
Fabian B Wadsworth, Michael J Heap, David E Damby, Kai-Uwe Hess, Jens Najorka, Jérémie Vasseur, Dominik Fahrner, Donald B Dingwell
During European prehistory, hilltop enclosures made from polydisperse particle-and-block stone walling were exposed to temperatures sufficient to partially melt the constituent stonework, leading to the preservation of glassy walls called 'vitrified forts'. During vitrification, the granular wall rocks partially melt, sinter viscously and densify, reducing inter-particle porosity. This process is strongly dependent on the solidus temperature, the particle sizes, the temperature-dependence of the viscosity of the evolving liquid phase, as well as the distribution and longevity of heat...
January 12, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28078370/evaluation-of-groundwater-quality-in-the-eastern-district-of-abu-dhabi-emirate-uae
#14
Mohamed M Mohamed, Ahmed Murad, RezaulKabir Chowdhury
Water samples were collected to evaluate the groundwater quality in the shallow unconfined alluvial aquifer in the eastern part of Abu-Dhabi Emirate, UAE. The chemical monitoring revealed some spatial variability in chemical parameters as influenced by matrix aquifer changes in geological formations. Results show that changes in groundwater chemistry in the aquifer is mainly controlled by evaporation, silicate mineral dissolution, evaporite dissolution, and cation exchange. The concentration increases were accounted for primarily by dissolved sodium, chloride, and sulphate...
January 11, 2017: Bulletin of Environmental Contamination and Toxicology
https://www.readbyqxmd.com/read/28074652/trends-in-methyl-tert-butyl-ether-concentrations-in-private-wells-in-southeast-new-hampshire-2005-to-2015
#15
Sarah M Flanagan, Joseph P Levitt, Joseph D Ayotte
In southeast New Hampshire, where reformulated gasoline was used from the 1990s to 2007, methyl tert-butyl ether (MtBE) concentrations ≥0.2 μg/L were found in water from 26.7% of 195 domestic wells sampled in 2005. Ten years later in 2015, and eight years after MtBE was banned, 10.3% continue to have MtBE. Most wells (140 of 195) had no MtBE detections (concentrations <0.2 μg/L) in 2005 and 2015. Of the remaining wells, MtBE concentrations increased in 4 wells, decreased in 47 wells, and did not change in 4 wells...
January 11, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28073771/out-of-borneo-biogeography-phylogeny-and-divergence-date-estimates-of-artocarpus-moraceae
#16
Evelyn W Williams, Elliot M Gardner, Robert Harris, Arunrat Chaveerach, Joan T Pereira, Nyree J C Zerega
BACKGROUND AND AIMS: The breadfruit genus (Artocarpus, Moraceae) includes valuable underutilized fruit tree crops with a centre of diversity in Southeast Asia. It belongs to the monophyletic tribe Artocarpeae, whose only other members include two small neotropical genera. This study aimed to reconstruct the phylogeny, estimate divergence dates and infer ancestral ranges of Artocarpeae, especially Artocarpus, to better understand spatial and temporal evolutionary relationships and dispersal patterns in a geologically complex region...
January 10, 2017: Annals of Botany
https://www.readbyqxmd.com/read/28069315/long-term-non-isothermal-reactive-transport-model-of-compacted-bentonite-concrete-and-corrosion-products-in-a-hlw-repository-in-clay
#17
Alba Mon, Javier Samper, Luis Montenegro, Acacia Naves, Jesús Fernández
Radioactive waste disposal in deep geological repositories envisages engineered barriers such as carbon-steel canisters, compacted bentonite and concrete liners. The stability and performance of the bentonite barrier could be affected by the corrosion products at the canister-bentonite interface and the hyper-alkaline conditions caused by the degradation of concrete at the bentonite-concrete interface. Additionally, the host clay formation could also be affected by the hyper-alkaline plume at the concrete-clay interface...
December 24, 2016: Journal of Contaminant Hydrology
https://www.readbyqxmd.com/read/28067596/comparative-analysis-of-the-complete-mitochondrial-genomes-of-three-geographical-topmouth-culter-culter-alburnus-groups-and-implications-for-their-phylogenetics
#18
Jianwu Shi, Dexia Wang, Junhua Wang, Junqing Sheng, Kou Peng, Beijuan Hu, Liugen Zeng, Minghe Xiao, Yijiang Hong
Topmouth culter (C. alburnus) is an important commercial fish in China. We compared the nucleotide variations in the mtDNA genomes among three geographical groups of Culter alburnus: Liangzi Lake, Hubei Province (referred to as LZH); Taihu Lake, Jiangsu Province (TH); and Poyang Lake, Jiangxi Province (PYH). The similarity of whole mtDNA genomes ranged from 0.992 to 0.999. The similarity among 13 protein-coding genes, 2 rRNA genes, and the D-loop sequences was found to range from 0.982 to 0.996. This is useful data for future designing work for making specific molecular marker for distinguishing individuals of C...
January 9, 2017: Bioscience, Biotechnology, and Biochemistry
https://www.readbyqxmd.com/read/28063520/zeta-potential-of-artificial-and-natural-calcite-in-aqueous-solution
#19
REVIEW
Dawoud Al Mahrouqi, Jan Vinogradov, Matthew D Jackson
Despite the broad range of interest and applications, controls on calcite surface charge in aqueous solution, especially at conditions relevant to natural systems, remain poorly understood. The primary data source to understand calcite surface charge comprises measurements of zeta potential. Here we collate and review previous measurements of zeta potential on natural and artificial calcite and carbonate as a resource for future studies, compare and contrast the results of these studies to determine key controls on zeta potential and where uncertainties remain, and report new measurements of zeta potential relevant to natural subsurface systems...
December 26, 2016: Advances in Colloid and Interface Science
https://www.readbyqxmd.com/read/28063236/reconstruction-of-travel-history-using-coupled-%C3%AE-18-o-and-87-sr-86-sr-measurements-of-hair
#20
Thuan H Chau, Brett J Tipple, Lihai Hu, Diego P Fernandez, Thure E Cerling, James R Ehleringer, Lesley A Chesson
RATIONALE: Oxygen isotope ratios (δ(18) O values) of hair largely reflect features of regional hydrology while strontium isotope ratios ((87) Sr/(86) Sr) are thought to reflect bedrock geology; combination of both isotope signatures may provide greater capacity for determining provenance and reconstructing travel history of an organism. To test this hypothesis, we compared the O-Sr isotope profiles of hair from domestic horses with known residency histories. METHODS: Tail hairs were collected from a pair of horses pastured together for a period of 16 months, one of which lived in a different location for the 8 months prior...
January 7, 2017: Rapid Communications in Mass Spectrometry: RCM
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