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https://www.readbyqxmd.com/read/28435888/continental-drift-and-speciation-of-the-cryptococcus-neoformans-and-cryptococcus-gattii-species-complexes
#1
Arturo Casadevall, Joudeh B Freij, Christopher Hann-Soden, John Taylor
Genomic analysis has placed the origins of two human-pathogenic fungi, the Cryptococcus gattii species complex and the Cryptococcus neoformans species complex, in South America and Africa, respectively. Molecular clock calculations suggest that the two species separated ~80 to 100 million years ago. This time closely approximates the breakup of the supercontinent Pangea, which gave rise to South America and Africa. On the basis of the geographic distribution of these two species complexes and the coincidence of the evolutionary divergence and Pangea breakup times, we propose that a spatial separation caused by continental drift resulted in the emergence of the C...
March 2017: MSphere
https://www.readbyqxmd.com/read/28433875/framing-causal-questions-about-the-past-the-cambrian-explosion-as-case-study
#2
Greg Priest
About 540 million years ago, a rapid radiation of animal phyla radically changed the Earth's biota in a geological eye-blink. What caused this "Cambrian explosion"? Over the years, paleontologists have pointed to a wide array of different physical mechanisms as the causal "trigger" for the explosion. More recently, some paleontologists have proposed complex causal pathways to which multiple physical mechanisms are said to have contributed. Despite their variety, these answers share an assumption that a single explanation can in principle be constructed that identifies some factor or confluence of factors as the cause of the Cambrian explosion...
April 20, 2017: Studies in History and Philosophy of Biological and Biomedical Sciences
https://www.readbyqxmd.com/read/28432368/indoor-radon-in-micro-geological-setting-of-an-indigenous-community-in-canada-a-pilot-study-for-hazard-identification
#3
Atanu Sarkar, Derek Hc Wilton, Erica Fitzgerald
BACKGROUND: Radon is the second leading cause of lung cancer after smoking. In Canada, the health authorities have no access to comprehensive profile of the communities built over uranium-rich micro-geological settings. The present indoor radon monitoring guideline is unable to provide an accurate identification of health hazards due to discounting several parameters of housing characteristics. OBJECTIVE: To explore indoor radon levels in a micro-geological setting known for high uranium in bedrock and to develop a theoretical model for a revised radon testing protocol...
April 2017: International Journal of Occupational and Environmental Medicine
https://www.readbyqxmd.com/read/28431380/recent-aspects-of-uranium-toxicology-in-medical-geology
#4
REVIEW
Geir Bjørklund, Olav Albert Christophersen, Salvatore Chirumbolo, Olle Selinus, Jan Aaseth
Uranium (U) is a chemo-toxic, radiotoxic and even a carcinogenic element. Due to its radioactivity, the effects of U on humans health have been extensively investigated. Prolonged U exposure may cause kidney disease and cancer. The geological distribution of U radionuclides is still a great concern for human health. Uranium in groundwater, frequently used as drinking water, and general environmental pollution with U raise concerns about the potential public health problem in several areas of Asia. The particular paleo-geological hallmark of India and other Southern Asiatic regions enhances the risk of U pollution in rural and urban communities...
April 18, 2017: Environmental Research
https://www.readbyqxmd.com/read/28431336/beam-induced-back-streaming-electron-suppression-analysis-for-an-accelerator-type-neutron-generator-designed-for-40-ar-39-ar-geochronology
#5
Cory Waltz, Mauricio Ayllon, Tim Becker, Lee Bernstein, Ka-Ngo Leung, Leo Kirsch, Paul Renne, Karl Van Bibber
A facility based on a next-generation, high-flux D-D neutron generator has been commissioned and it is now operational at the University of California, Berkeley. The current generator designed for (40)Ar/(39)Ar dating of geological materials produces nearly monoenergetic 2.45MeV neutrons at outputs of 10(8)n/s. The narrow energy range is advantageous relative to the (235)U fission spectrum neutrons due to (i) reduced (39)Ar recoil energy, (ii) minimized production of interfering argon isotopes from K, Ca, and Cl, and (iii) reduced total activity for radiological safety and waste generation...
April 13, 2017: Applied Radiation and Isotopes
https://www.readbyqxmd.com/read/28431105/extinction-vs-rapid-radiation-the-juxtaposed-evolutionary-histories-of-coelotine-spiders-support-the-eocene-oligocene-orogenesis-of-the-tibetan-plateau
#6
Zhe Zhao, Shuqiang Li
Evolutionary biology has long been concerned with how changing environments affect and drive the spatiotemporal development of organisms. Coelotine spiders (Agelenidae: Coelotinae) are common species in the temperate and subtropical areas of the Northern Hemisphere. Their long evolutionary history and the extremely imbalanced distribution of species richness suggest that Eurasian environments, especially since the Cenozoic, are the drivers of their diversification. We use phylogenetics, molecular dating, ancestral area reconstructions, diversity, and ecological niche analyses to investigate the spatiotemporal evolution of 286 coelotine species from throughout the region...
April 20, 2017: Systematic Biology
https://www.readbyqxmd.com/read/28430153/a-novel-method-of-localization-for-moving-objects-with-an-alternating-magnetic-field
#7
Xiang Gao, Shenggang Yan, Bin Li
Magnetic detection technology has wide applications in the fields of geological exploration, biomedical treatment, wreck removal and localization of unexploded ordinance. A large number of methods have been developed to locate targets with static magnetic fields, however, the relation between the problem of localization of moving objectives with alternating magnetic fields and the localization with a static magnetic field is rarely studied. A novel method of target localization based on coherent demodulation was proposed in this paper...
April 21, 2017: Sensors
https://www.readbyqxmd.com/read/28427815/the-swedish-radiological-environmental-protection-regulations-applied-in-a-review-of-a-license-application-for-a-geological-repository-for-spent-nuclear-fuel
#8
Pål Andersson, Karolina Stark, Shulan Xu, Maria Nordén, Björn Dverstorp
For the first time, a system for specific consideration of radiological environmental protection has been applied in a major license application in Sweden. In 2011 the Swedish Nuclear Fuel & Waste Management Co. (SKB) submitted a license application for construction of a geological repository for spent nuclear fuel at the Forsmark site. The license application is supported by a post-closure safety assessment, which in accordance with regulatory requirements includes an assessment of environmental consequences...
April 17, 2017: Journal of Environmental Radioactivity
https://www.readbyqxmd.com/read/28426985/current-uses-of-ground-penetrating-radar-in-groundwater-dependent-ecosystems-research
#9
REVIEW
Catarina Paz, Francisco J Alcalá, Jorge M Carvalho, Luís Ribeiro
Ground penetrating radar (GPR) is a high-resolution technique widely used in shallow groundwater prospecting. This makes GPR ideal to characterize the hydrogeological functioning of groundwater-dependent ecosystems (GDE). This paper reviews current uses of GPR in GDE research through the construction of a database comprising 91 worldwide GPR case studies selected from the literature and classified according to (1) geological environments favouring GDE; (2) hydrogeological research interests; and (3) field technical and (4) hydrogeological conditions of the survey...
April 17, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28423077/early-devonian-late-emsian-shark-fin-remains-chondrichthyes-from-the-paran%C3%A3-basin-southern-brazil
#10
Martha Richter, Elvio P Bosetti, Rodrigo S Horodyski
We report on the pioneering discovery of Devonian fish remains in the Paraná Basin, which represents the southernmost record of fishes from that period in mainland South America. The material comes from an outcrop at the lower portion of the São Domingos Formation, within Sequence C of the Paraná-Apucarana sub-basin in Tibagi, State of Paraná. Marine invertebrates are abundant in the same strata. The dark colored fish remains were collected in situ and represent natural moulds of partially articulated shark fin rays (radials)...
January 2017: Anais da Academia Brasileira de Ciências
https://www.readbyqxmd.com/read/28419899/the-long-term-tsunami-impact-evolution-of-iron-speciation-and-major-elements-concentration-in-tsunami-deposits-from-thailand
#11
Lidia Kozak, Przemyslaw Niedzielski
The article describes the unique studies of the chemical composition changes of new geological object (tsunami deposits in south Thailand - Andaman Sea Coast) during four years (2005-2008) from the beginning of formation of it (deposition of tsunami transported material, 26 December 2004). The chemical composition of the acid leachable fraction of the tsunami deposits has been studied in the scope of concentration macrocompounds - concentration of calcium, magnesium, iron, manganese and iron speciation - the occurrence of Fe(II), Fe(III) and non-ionic iron species described as complexed iron (Fe complex)...
April 15, 2017: Chemosphere
https://www.readbyqxmd.com/read/28418705/accurate-differentiation-of-carotenoid-pigments-using-flight-representative-raman-spectrometers
#12
Cedric Malherbe, Ian B Hutchinson, Melissa McHugh, Richard Ingley, Jan Jehlička, Howell G M Edwards
Raman spectrometers will be utilized on two Mars rover missions, ExoMars and Mars 2020, in the near future, to search for evidence of life and habitable geological niches on Mars. Carotenoid pigments are recognized target biomarkers, and as they are highly active in Raman spectroscopy, they can be readily used to characterize the capabilities of space representative instrumentation. As part of the preparatory work being performed for the ExoMars mission, a gypsum crust colonized by microorganisms was interrogated with commercial portable Raman instruments and a flight representative Raman laser spectrometer...
April 2017: Astrobiology
https://www.readbyqxmd.com/read/28418663/airborne-quantification-of-methane-emissions-over-the-four-corners-region
#13
Mackenzie L Smith, Alexander Gvakharia, Eric A Kort, Colm Sweeney, Stephen A Conley, Ian C Faloona, Tim Newberger, Russell Schnell, Stefan Schwietzke, Sonja Wolter
Methane (CH4) is a potent greenhouse gas and the primary component of natural gas. The San Juan Basin (SJB) is one of the largest coal-bed methane producing regions in North America and, including gas production from conventional and shale sources, contributes ~2% of U.S. natural gas production in 2015. In this work, we quantify the CH4 flux from the SJB using continuous atmospheric sampling from aircraft collected during the TOPDOWN2015 field campaign in April 2015. Using five independent days of measurements and the aircraft-based mass balance method, we calculate an average CH4 flux of 0...
April 18, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28417168/rdx-degradation-in-bioaugmented-model-aquifer-columns-under-aerobic-and-low-oxygen-conditions
#14
Mark E Fuller, Paul B Hatzinger, Charles W Condee, Christina Andaya, Rachel Rezes, Mandy M Michalsen, Fiona H Crocker, Karl J Indest, Carina M Jung, G Alon Blakeney, Jonathan D Istok, Steven A Hammett
Degradation of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in laboratory columns following biostimulation and bioaugmentation was investigated using sediment and groundwater from a contaminated aquifer at a US Navy facility. No RDX degradation was observed following aerobic biostimulation with either fructose or lactate (both 0.1 mM) prior to bioaugmentation. Replicate columns were then bioaugmented with either Gordonia sp. KTR9, Pseudomonas fluorescens I-C (Ps I-C), or both strains. Under aerobic conditions (influent dissolved oxygen (DO) >6 mg/L), RDX was degraded following the addition of fructose, and to a lesser extent with lactate, in columns bioaugmented with KTR9...
April 17, 2017: Applied Microbiology and Biotechnology
https://www.readbyqxmd.com/read/28416728/global-water-cycle-and-the-coevolution-of-the-earth-s-interior-and-surface-environment
#15
Jun Korenaga, Noah J Planavsky, David A D Evans
The bulk Earth composition contains probably less than 0.3% of water, but this trace amount of water can affect the long-term evolution of the Earth in a number of different ways. The foremost issue is the occurrence of plate tectonics, which governs almost all aspects of the Earth system, and the presence of water could either promote or hinder the operation of plate tectonics, depending on where water resides. The global water cycle, which circulates surface water into the deep mantle and back to the surface again, could thus have played a critical role in the Earth's history...
May 28, 2017: Philosophical Transactions. Series A, Mathematical, Physical, and Engineering Sciences
https://www.readbyqxmd.com/read/28416727/remotely-distinguishing-and-mapping-endogenic-water-on-the-moon
#16
Rachel L Klima, Noah E Petro
Water and/or hydroxyl detected remotely on the lunar surface originates from several sources: (i) comets and other exogenous debris; (ii) solar-wind implantation; (iii) the lunar interior. While each of these sources is interesting in its own right, distinguishing among them is critical for testing hypotheses for the origin and evolution of the Moon and our Solar System. Existing spacecraft observations are not of high enough spectral resolution to uniquely characterize the bonding energies of the hydroxyl molecules that have been detected...
May 28, 2017: Philosophical Transactions. Series A, Mathematical, Physical, and Engineering Sciences
https://www.readbyqxmd.com/read/28416726/d-h-ratios-of-the-inner-solar-system
#17
REVIEW
L J Hallis
The original hydrogen isotope (D/H) ratios of different planetary bodies may indicate where each body formed in the Solar System. However, geological and atmospheric processes can alter these ratios through time. Over the past few decades, D/H ratios in meteorites from Vesta and Mars, as well as from S- and C-type asteroids, have been measured. The aim of this article is to bring together all previously published data from these bodies, as well as the Earth, in order to determine the original D/H ratio for each of these inner Solar System planetary bodies...
May 28, 2017: Philosophical Transactions. Series A, Mathematical, Physical, and Engineering Sciences
https://www.readbyqxmd.com/read/28416654/reconstructed-ancestral-enzymes-suggest-long-term-cooling-of-earth-s-photic-zone-since-the-archean
#18
Amanda K Garcia, J William Schopf, Shin-Ichi Yokobori, Satoshi Akanuma, Akihiko Yamagishi
Paleotemperatures inferred from the isotopic compositions (δ(18)O and δ(30)Si) of marine cherts suggest that Earth's oceans cooled from 70 ± 15 °C in the Archean to the present ∼15 °C. This interpretation, however, has been subject to question due to uncertainties regarding oceanic isotopic compositions, diagenetic or metamorphic resetting of the isotopic record, and depositional environments. Analyses of the thermostability of reconstructed ancestral enzymes provide an independent method by which to assess the temperature history inferred from the isotopic evidence...
April 17, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28415221/dynamic-phases-of-active-matter-systems-with-quenched-disorder
#19
Cs Sándor, A Libál, C Reichhardt, C J Olson Reichhardt
Depinning and nonequilibrium transitions within sliding states in systems driven over quenched disorder arise across a wide spectrum of size scales ranging from atomic friction at the nanoscale, flux motion in type II superconductors at the mesoscale, colloidal motion in disordered media at the microscale, and plate tectonics at geological length scales. Here we show that active matter or self-propelled particles interacting with quenched disorder under an external drive represents a class of system that can also exhibit pinning-depinning phenomena, plastic flow phases, and nonequilibrium sliding transitions that are correlated with distinct morphologies and velocity-force curve signatures...
March 2017: Physical Review. E
https://www.readbyqxmd.com/read/28412980/arctic-systems-in-the-quaternary-ecological-collision-faunal-mosaics-and-the-consequences-of-a-wobbling-climate
#20
E P Hoberg, J A Cook, S J Agosta, W Boeger, K E Galbreath, S Laaksonen, S J Kutz, D R Brooks
Climate oscillations and episodic processes interact with evolution, ecology and biogeography to determine the structure and complex mosaic that is the biosphere. Parasites and parasite-host assemblages are key components in a general explanatory paradigm for global biodiversity. We explore faunal assembly in the context of Quaternary time frames of the past 2.6 million years, a period dominated by episodic shifts in climate. Climate drivers cross a continuum from geological to contemporary timescales and serve to determine the structure and distribution of complex biotas...
April 17, 2017: Journal of Helminthology
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