keyword
MENU ▼
Read by QxMD icon Read
search

Geology

keyword
https://www.readbyqxmd.com/read/28230127/theory-of-chaotic-orbital-variations-confirmed-by-cretaceous-geological-evidence
#1
Chao Ma, Stephen R Meyers, Bradley B Sageman
Variations in the Earth's orbit and spin vector are a primary control on insolation and climate; their recognition in the geological record has revolutionized our understanding of palaeoclimate dynamics, and has catalysed improvements in the accuracy and precision of the geological timescale. Yet the secular evolution of the planetary orbits beyond 50 million years ago remains highly uncertain, and the chaotic dynamical nature of the Solar System predicted by theoretical models has yet to be rigorously confirmed by well constrained (radioisotopically calibrated and anchored) geological data...
February 22, 2017: Nature
https://www.readbyqxmd.com/read/28229521/microbial-potential-for-carbon-and-nutrient-cycling-in-a-geogenic-supercritical-carbon-dioxide-reservoir
#2
Adam J E Freedman, BoonFei Tan, Janelle R Thompson
Microorganisms catalyze carbon cycling and biogeochemical reactions in the deep subsurface and thus may be expected to influence the fate of injected supercritical (sc) CO2 following geological carbon sequestration (GCS). We hypothesized that natural subsurface scCO2 reservoirs, which serve as analogs for the long-term fate of sequestered scCO2 , harbor a "deep carbonated biosphere" with carbon cycling potential. We sampled subsurface fluids from scCO2 -water separators at a natural scCO2 reservoir at McElmo Dome, Colorado for analysis of 16S rRNA gene diversity and metagenome content...
February 22, 2017: Environmental Microbiology
https://www.readbyqxmd.com/read/28229257/potential-ecological-risk-assessment-and-predicting-zinc-accumulation-in-soils
#3
Agnieszka Baran, Jerzy Wieczorek, Ryszard Mazurek, Krzysztof Urbański, Agnieszka Klimkowicz-Pawlas
The aims of this study were to investigate zinc content in the studied soils; evaluate the efficiency of geostatistics in presenting spatial variability of zinc in the soils; assess bioavailable forms of zinc in the soils and to assess soil-zinc binding ability; and to estimate the potential ecological risk of zinc in soils. The study was conducted in southern Poland, in the Malopolska Province. This area is characterized by a great diversity of geological structures and types of land use and intensity of industrial development...
February 22, 2017: Environmental Geochemistry and Health
https://www.readbyqxmd.com/read/28229194/screening-level-assessment-of-metal-concentrations-in-streambed-sediments-and-floodplain-soils-within-the-grand-lake-watershed-in-northeastern-oklahoma-usa
#4
Ean M Garvin, Cas F Bridge, Meredith S Garvin
Metal releases have been received by the Grand Lake watershed from the Tri-State Mining District (TSMD) since the mid 1800s. To address data gaps in metal distributions in the Oklahoma portion of the watershed, streambed sediment and floodplain soil was sampled on various streams. The <63-µm fraction was analyzed for Cd, Pb, and Zn concentrations by portable X-ray fluorescence spectroscopy and inductively coupled plasma-mass spectrometry. Mean metal concentration results at reference transects indicated that background sediment/soil concentrations for Cd, Pb, and Zn within the watershed were 0...
February 22, 2017: Archives of Environmental Contamination and Toxicology
https://www.readbyqxmd.com/read/28225060/new-limits-of-secondary-%C3%AE-relaxation
#5
Satya N Tripathy, Marzena Rams-Baron, Zaneta Wojnarowska, Justyna Knapik-Kowalczuk, Marian Paluch
Glass is an ultraviscous liquid that ceases to flow on a laboratory timescale but continues to relax on a geological timescale. Quintessentially, it has become hopeless for humans to explore the equilibrium behavior of glass, although the technology of glass making witness a remarkable advance. In this work, we propose a novel thermodynamic path to prepare a high density amorphous state of matter (carvedilol dihydrogen phosphate) using high pressure. In addition, we provide the impeccable experimental evidence of heterogeneous nature of secondary β-relaxation and probe its properties to understand the various aspects of pressure densified glass, such as dynamics, packing and disorder...
February 22, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28223966/geological-and-geochemical-controls-on-subsurface-microbial-life-in-the-samail-ophiolite-oman
#6
Kaitlin R Rempfert, Hannah M Miller, Nicolas Bompard, Daniel Nothaft, Juerg M Matter, Peter Kelemen, Noah Fierer, Alexis S Templeton
Microbial abundance and diversity in deep subsurface environments is dependent upon the availability of energy and carbon. However, supplies of oxidants and reductants capable of sustaining life within mafic and ultramafic continental aquifers undergoing low-temperature water-rock reaction are relatively unknown. We conducted an extensive analysis of the geochemistry and microbial communities recovered from fluids sampled from boreholes hosted in peridotite and gabbro in the Tayin block of the Samail Ophiolite in the Sultanate of Oman...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28223715/massive-production-of-abiotic-methane-during-subduction-evidenced-in-metamorphosed-ophicarbonates-from-the-italian-alps
#7
Alberto Vitale Brovarone, Isabelle Martinez, Agnès Elmaleh, Roberto Compagnoni, Carine Chaduteau, Cristiano Ferraris, Imène Esteve
Alteration of ultramafic rocks plays a major role in the production of hydrocarbons and organic compounds via abiotic processes on Earth and beyond and contributes to the redistribution of C between solid and fluid reservoirs over geological cycles. Abiotic methanogenesis in ultramafic rocks is well documented at shallow conditions, whereas natural evidence at greater depths is scarce. Here we provide evidence for intense high-pressure abiotic methanogenesis by reduction of subducted ophicarbonates. Protracted (≥0...
February 22, 2017: Nature Communications
https://www.readbyqxmd.com/read/28220864/a-phylogenetic-perspective-on-biogeographical-divergence-of-the-flora-in-yunnan-southwestern-china
#8
Shuiyin Liu, Hua Zhu, Jie Yang
In recent years, an increasing number of studies incorporated biogeography with phylogenetic analyses to reveal the origin and evolutionary history of specific floras. In this study, we constructed the mega-phylogeny of the floras of three representative regions across Yunnan, southwestern China. We analyzed the phylogenetic structure and beta diversity based on the presence/absence of species (genus or family) data to investigate the phylogenetic patterns of regional floras. We found conspicuous divergence at the genus and species level in the pattern of phylogenetic structures, which most likely related to historical biogeography...
February 21, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28218298/horizontal-sliding-of-kilometre-scale-hot-spring-area-during-the-2016-kumamoto-earthquake
#9
Takeshi Tsuji, Jun'ichiro Ishibashi, Kazuya Ishitsuka, Ryuichi Kamata
We report horizontal sliding of the kilometre-scale geologic block under the Aso hot springs (Uchinomaki area) caused by vibrations from the 2016 Kumamoto earthquake (Mw 7.0). Direct borehole observations demonstrate the sliding along the horizontal geological formation at ~50 m depth, which is where the shallowest hydrothermal reservoir developed. Owing to >1 m northwest movement of the geologic block, as shown by differential interferometric synthetic aperture radar (DInSAR), extensional open fissures were generated at the southeastern edge of the horizontal sliding block, and compressional deformation and spontaneous fluid emission from wells were observed at the northwestern edge of the block...
February 20, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28217543/effect-of-fluoridated-water-on-intelligence-in-10-12-year-old-school-children
#10
A Aravind, R S Dhanya, Ajay Narayan, George Sam, V J Adarsh, M Kiran
AIM: The aim of the present study was to evaluate the relationship of drinking water fluoride levels with children's intelligence quotient (IQ). MATERIALS AND METHODS: Water was collected from initially identified endemic fluoride regions according to the geological research of Government of India. Fluoride concentration of the water was assessed by utilizing fluoride ion selective electrode, Orion 9609BN, and categorized on the basis of fluoride concentration into low, medium, and high-fluoride regions, i...
December 2016: Journal of International Society of Preventive & Community Dentistry
https://www.readbyqxmd.com/read/28216136/arsenic-speciation-in-the-lower-athabasca-river-watershed-a-geochemical-investigation-of-the-dissolved-and-particulate-phases
#11
Mark W Donner, Muhammad Babar Javed, William Shotyk, Kevin A Francesconi, Tariq Siddique
Human and ecosystem health concerns for arsenic (As) in the lower Athabasca River downstream of Athabasca Bituminous Sands (ABS) mining (Alberta, Canada) prompted an investigation to determine its forms in surface and groundwater upstream and downstream of industry. Dissolved As species, together with total and particulate As, were used to evaluate the potential bioavailability of As in water as well as to decipher inputs from natural geological processes and ABS mining and upgrading activities. Water samples were collected from the river in October at 13 locations in 2014 and 19 locations in 2015, spanning up to 125 km...
February 17, 2017: Environmental Pollution
https://www.readbyqxmd.com/read/28215805/private-well-groundwater-quality-in-west-virginia-usa-2010
#12
R K Law, M W Murphy, E Choudhary
The Centers for Disease Control and Prevention (CDC), in collaboration with the West Virginia Bureau of Public Health (BPH), initiated an investigation to characterize private well water quality in West Virginia. The objective was to better characterize private well water across various aquifer geologies by testing household drinking water samples and comparing them to EPA's National Primary Drinking Water Standards. The BPH selected ten counties representing three regions to capture geologically diverse areas that represent varying aquifer geology...
February 16, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28211601/biogeography-of-nodulated-legumes-and-their-nitrogen-fixing-symbionts
#13
REVIEW
Janet I Sprent, Julie Ardley, Euan K James
Contents I. II. III. IV. V. VI. VII. VIII. References SUMMARY: In the last decade, analyses of both molecular and morphological characters, including nodulation, have led to major changes in our understanding of legume taxonomy. In parallel there has been an explosion in the number of genera and species of rhizobia known to nodulate legumes. No attempt has been made to link these two sets of data or to consider them in a biogeographical context. This review aims to do this by relating the data to the evolution of the two partners: it highlights both longitudinal and latitudinal trends and considers these in relation to the location of major land masses over geological time...
February 17, 2017: New Phytologist
https://www.readbyqxmd.com/read/28196688/biodiversity-and-topographic-complexity-modern-and-geohistorical-perspectives
#14
REVIEW
Catherine Badgley, Tara M Smiley, Rebecca Terry, Edward B Davis, Larisa R G DeSantis, David L Fox, Samantha S B Hopkins, Tereza Jezkova, Marjorie D Matocq, Nick Matzke, Jenny L McGuire, Andreas Mulch, Brett R Riddle, V Louise Roth, Joshua X Samuels, Caroline A E Strömberg, Brian J Yanites
Topographically complex regions on land and in the oceans feature hotspots of biodiversity that reflect geological influences on ecological and evolutionary processes. Over geologic time, topographic diversity gradients wax and wane over millions of years, tracking tectonic or climatic history. Topographic diversity gradients from the present day and the past can result from the generation of species by vicariance or from the accumulation of species from dispersal into a region with strong environmental gradients...
February 11, 2017: Trends in Ecology & Evolution
https://www.readbyqxmd.com/read/28195495/accuracy-enhancement-of-raman-spectroscopy-using-complementary-laser-induced-breakdown-spectroscopy-libs-with-geologically-mixed-samples
#15
Soojin Choi, Dongyoung Kim, Junho Yang, Jack J Yoh
Quantitative Raman analysis was carried out with geologically mixed samples that have various matrices. In order to compensate the matrix effect in Raman shift, laser-induced breakdown spectroscopy (LIBS) analysis was performed. Raman spectroscopy revealed the geological materials contained in the mixed samples. However, the analysis of a mixture containing different matrices was inaccurate due to the weak signal of the Raman shift, interference, and the strong matrix effect. On the other hand, the LIBS quantitative analysis of atomic carbon and calcium in mixed samples showed high accuracy...
January 1, 2017: Applied Spectroscopy
https://www.readbyqxmd.com/read/28194673/assessment-of-groundwater-vulnerability-using-supervised-committee-to-combine-fuzzy-logic-models
#16
Ata Allah Nadiri, Maryam Gharekhani, Rahman Khatibi, Asghar Asghari Moghaddam
Vulnerability indices of an aquifer assessed by different fuzzy logic (FL) models often give rise to differing values with no theoretical or empirical basis to establish a validated baseline or to develop a comparison basis between the modeling results and baselines, if any. Therefore, this research presents a supervised committee fuzzy logic (SCFL) method, which uses artificial neural networks to overarch and combine a selection of FL models. The indices are expressed by the widely used DRASTIC framework, which include geological, hydrological, and hydrogeological parameters often subject to uncertainty...
February 13, 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/28193877/origin-of-microbial-biomineralization-and-magnetotaxis-during-the-archean
#17
Wei Lin, Greig A Paterson, Qiyun Zhu, Yinzhao Wang, Evguenia Kopylova, Ying Li, Rob Knight, Dennis A Bazylinski, Rixiang Zhu, Joseph L Kirschvink, Yongxin Pan
Microbes that synthesize minerals, a process known as microbial biomineralization, contributed substantially to the evolution of current planetary environments through numerous important geochemical processes. Despite its geological significance, the origin and evolution of microbial biomineralization remain poorly understood. Through combined metagenomic and phylogenetic analyses of deep-branching magnetotactic bacteria from the Nitrospirae phylum, and using a Bayesian molecular clock-dating method, we show here that the gene cluster responsible for biomineralization of magnetosomes, and the arrangement of magnetosome chain(s) within cells, both originated before or near the Archean divergence between the Nitrospirae and Proteobacteria This phylogenetic divergence occurred well before the Great Oxygenation Event...
February 13, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28193874/six-centuries-of-geomagnetic-intensity-variations-recorded-by-royal-judean-stamped-jar-handles
#18
Erez Ben-Yosef, Michael Millman, Ron Shaar, Lisa Tauxe, Oded Lipschits
Earth's magnetic field, one of the most enigmatic physical phenomena of the planet, is constantly changing on various time scales, from decades to millennia and longer. The reconstruction of geomagnetic field behavior in periods predating direct observations with modern instrumentation is based on geological and archaeological materials and has the twin challenges of (i) the accuracy of ancient paleomagnetic estimates and (ii) the dating of the archaeological material. Here we address the latter by using a set of storage jar handles (fired clay) stamped by royal seals as part of the ancient administrative system in Judah (Jerusalem and its vicinity)...
February 13, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28190688/antimony-as-a-global-dilemma-geochemistry-mobility-fate-and-transport
#19
REVIEW
Indika Herath, Meththika Vithanage, Jochen Bundschuh
Elevated concentrations of antimony (Sb) in environmental, biological and geochemical systems originating from natural, geological and anthropogenic sources are of particular global concern. This review presents a critical overview of natural geochemical processes which trigger the mobilization of Sb from its host mineral phases and related rocks to the surrounding environments. The primary source of Sb contamination in the environment is geogenic. The geochemical characteristics of Sb are determined by its oxidation states, speciation and redox transformation...
February 9, 2017: Environmental Pollution
https://www.readbyqxmd.com/read/28189114/nano-scale-synthesis-of-the-complex-silicate-minerals-forsterite-and-enstatite
#20
Lawrence M Anovitz, Adam J Rondinone, Lindsay Sochalski-Kolbus, Jörgen Rosenqvist, Michael C Cheshire
Olivine is a relatively common family of silicate minerals in many terrestrial and extraterrestrial environments, and is also useful as a refractory ceramic. A capability to synthesize fine particles of olivine will enable additional studies on surface reactivity under geologically relevant conditions. This paper presents a method for the synthesis of nanocrystalline samples of the magnesium end-member, forsterite (Mg2SiO4) in relatively large batches (15-20g) using a sol-gel/surfactant approach. Magnesium methoxide and tetraethylorthosilicate (TEOS) are refluxed in a toluene/methanol mixture using dodecylamine as a surfactant and tert-butyl amine and water as hydrolysis agents...
January 18, 2017: Journal of Colloid and Interface Science
keyword
keyword
31664
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"