211 research outputs found
Pervasive deformation of an oceanic plate and relationship to large >Mw 8 intraplate earthquakes: The northern Wharton Basin, Indian Ocean
Large-magnitude intraplate earthquakes within the ocean basins are not well understood. The Mw 8.6 and Mw 8.2 strike-slip intraplate earthquakes on 11 April 2012, while clearly occurring in the equatorial Indian Ocean diffuse plate boundary zone, are a case in point, with disagreement on the nature of the focal mechanisms and the faults that ruptured. We use bathymetric and seismic reflection data from the rupture area of the earthquakes in the northern Wharton Basin to demonstrate pervasive brittle deformation between the Ninetyeast Ridge and the Sunda subduction zone. In addition to evidence of recent strike-slip deformation along approximately north-southâtrending fossil fracture zones, we identify a new type of deformation structure in the Indian Ocean: conjugate Riedel shears limited to the sediment section and oriented oblique to the north-south fracture zones. The Riedel shears developed in the Miocene, at a similar time to the onset of diffuse deformation in the central Indian Ocean. However, left-lateral strike-slip reactivation of existing fracture zones started earlier, in the Paleocene to early Eocene, and compartmentalizes the Wharton Basin. Modeled rupture during the 11 April 2012 intraplate earthquakes is consistent with the location of two reactivated, closely spaced, approximately north-southâtrending fracture zones. However, we find no evidence for WNW-ESEâtrending faults in the shallow crust, which is at variance with most of the earthquake fault models
Effect of volcanic dykes on coastal groundwater flow and saltwater intrusion : a field-scale multiphysics approach and parameter evaluation
Acknowledgments This research was primarily based on research grantâaided by the Irish Department of Communications, Energy and Natural Resources under the National Geoscience Programme 2007â2013. It also benefited from complementary funding from the Scottish Alliance for Geoscience, Environment and Society (SAGES). We acknowledge the contribution in data acquisition of the MSc students in Environmental Engineering at Queen's University Belfast, the landowner for access to the inland fields and the Department of Geography, Archaeology and Paleoecology at QUB for provision of the tidal model of Belfast Lough. The data used are listed in the references, tables, and figures and are available from the corresponding author upon demand. We acknowledge the constructive comments by the Associate Editor and three reviewers, which helped in improving the final manuscript.Peer reviewedPublisher PD
The Vehicle, Spring 1997
Vol. 38, No. 2
Table of Contents
Poetry:
Don QuixotePatrick Scanlanpage 1
Last SupperChristine Starrpage 1
Marriage VowsKristopher Clausingpage 2
The LibraryPatrick Lairpage 4
GuruJohn Dylan McNeilpage 5
Tripping in OzKim Evanspage 5
TranceStephanie Kavanaughpage 6
The CleftEmilie Roypage 7
FlannelAmanda Watsonpage 8
Strip PokerEbben Moorepage 8
IceJohn Dylan McNeilpage 9
ChloeMichael Kawapage 11
OrchardCarmella Cosenzapage 12
Jenn & Cookie MonsterJacob Tolbertpage 13
Barry ManilowKatie Wrightpage 14
GoodbyesShannon Goodallpage 15
Prose:
Alice (A Short, Short Story)Carmella Cosenzapage 17
UntitledJoe Robesonpage 17
A New World AloneKendall W. Baumanpage 22
Biographiespage 35https://thekeep.eiu.edu/vehicle/1069/thumbnail.jp
Aqueous-phase mechanism for secondary organic aerosol formation from isoprene: application to the southeast United States and co-benefit of SO2 emission controls
Isoprene emitted by vegetation is an important precursor of secondary organic aerosol (SOA), but the mechanism and yields are uncertain. Aerosol is prevailingly aqueous under the humid conditions typical of isoprene-emitting regions. Here we develop an aqueous-phase mechanism for isoprene SOA formation coupled to a detailed gas-phase isoprene oxidation scheme. The mechanism is based on aerosol reactive uptake coefficients (γ) for water-soluble isoprene oxidation products, including sensitivity to aerosol acidity and nucleophile concentrations. We apply this mechanism to simulation of aircraft (SEAC4RS) and ground-based (SOAS) observations over the southeast US in summer 2013 using the GEOS-Chem chemical transport model. Emissions of nitrogen oxides (NOx ⥠NO + NO2) over the southeast US are such that the peroxy radicals produced from isoprene oxidation (ISOPO2) react significantly with both NO (high-NOx pathway) and HO2 (low-NOx pathway), leading to different suites of isoprene SOA precursors. We find a mean SOA mass yield of 3.3 % from isoprene oxidation, consistent with the observed relationship of total fine organic aerosol (OA) and formaldehyde (a product of isoprene oxidation). Isoprene SOA production is mainly contributed by two immediate gas-phase precursors, isoprene epoxydiols (IEPOX, 58 % of isoprene SOA) from the low-NOx pathway and glyoxal (28 %) from both low- and high-NOx pathways. This speciation is consistent with observations of IEPOX SOA from SOAS and SEAC4RS. Observations show a strong relationship between IEPOX SOA and sulfate aerosol that we explain as due to the effect of sulfate on aerosol acidity and volume. Isoprene SOA concentrations increase as NOx emissions decrease (favoring the low-NOx pathway for isoprene oxidation), but decrease more strongly as SO2 emissions decrease (due to the effect of sulfate on aerosol acidity and volume). The US Environmental Protection Agency (EPA) projects 2013-2025 decreases in anthropogenic emissions of 34 % for NOx (leading to a 7 % increase in isoprene SOA) and 48 % for SO2 (35 % decrease in isoprene SOA). Reducing SO2 emissions decreases sulfate and isoprene SOA by a similar magnitude, representing a factor of 2 co-benefit for PM2.5 from SO2 emission controls
Impact of InâCloud Aqueous Processes on the Chemistry and Transport of Biogenic Volatile Organic Compounds
We investigate the impacts of cloud aqueous processes on the chemistry and transport of biogenic volatile organic compounds (BVOC) using the National Center for Atmospheric Researchâs largeâeddy simulation code with an updated chemical mechanism that includes both gasâ and aqueousâphase reactions. We simulate transport and chemistry for a meteorological case with a diurnal pattern of nonprecipitating cumulus clouds from the BaltimoreâWashington area DISCOVERâAQ campaign. We evaluate two scenarios with and without aqueousâphase chemical reactions. In the cloud layer (2â3Â km), the addition of aqueous phase reactions decreases HCHO by 18% over the domain due to its solubility and the fast depletion from aqueous reactions, resulting in a corresponding decrease in radical oxidants (e.g., 18% decrease in OH). The decrease of OH increases the mixing ratios of isoprene and methacrolein (MACR) (100% and 15%, respectively) in the cloud layer because the reaction rate is lower. Aqueousâphase reactions can modify the segregation between OH and BVOC by changing the sign of the segregation intensity, causing up to 55% reduction in the isopreneâOH reaction rate and 40% reduction for the MACRâOH reaction when clouds are present. Analysis of the isopreneâOH covariance budget shows the chemistry term is the primary driver of the strong segregation in clouds, triggered by the decrease in OH. All organic acids except acetic acid are formed only through aqueousâphase reactions. For acids formed in the aqueous phase, turbulence mixes these compounds on short time scales, with the nearâsurface mixing ratios of these acids reaching 20% of the mixing ratios in the cloud layer within 1Â h of cloud formation.Key PointsAdding aqueous chemistry to a LES model reduces OH by up to 25% and increases isoprene, promoting their segregation in cloudsCovariance of isoprene oxidation products with OH changes sign (from positive to negative) when aqueousâphase reactions are includedInâcloud formation of organic acids increases their mixing ratios throughout the boundary layerPeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/139963/1/jgrd54176_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/139963/2/jgrd54176.pd
Social Cognition for Human-Robot SymbiosisâChallenges and Building Blocks
The next generation of robot companions or robot working partners will need to satisfy social requirements somehow similar to the famous laws of robotics envisaged by Isaac Asimov time ago (Asimov, 1942). The necessary technology has almost reached the required level, including sensors and actuators, but the cognitive organization is still in its infancy and is only partially supported by the current understanding of brain cognitive processes. The brain of symbiotic robots will certainly not be a âpositronicâ replica of the human brain: probably, the greatest part of it will be a set of interacting computational processes running in the cloud. In this article, we review the challenges that must be met in the design of a set of interacting computational processes as building blocks of a cognitive architecture that may give symbiotic capabilities to collaborative robots of the next decades: (1) an animated body-schema; (2) an imitation machinery; (3) a motor intentions machinery; (4) a set of physical interaction mechanisms; and (5) a shared memory system for incremental symbiotic development. We would like to stress that our approach is totally un-hierarchical: the five building blocks of the shared cognitive architecture are fully bi-directionally connected. For example, imitation and intentional processes require the âservicesâ of the animated body schema which, on the other hand, can run its simulations if appropriately prompted by imitation and/or intention, with or without physical interaction. Successful experiences can leave a trace in the shared memory system and chunks of memory fragment may compete to participate to novel cooperative actions. And so on and so forth. At the heart of the system is lifelong training and learning but, different from the conventional learning paradigms in neural networks, where learning is somehow passively imposed by an external agent, in symbiotic robots there is an element of free choice of what is worth learning, driven by the interaction between the robot and the human partner. The proposed set of building blocks is certainly a rough approximation of what is needed by symbiotic robots but we believe it is a useful starting point for building a computational framework
Examining the effectiveness of general practitioner and nurse promotion of electronic cigarettes versus standard care for smoking reduction and abstinence in hardcore smokers with smoking-related chronic disease:protocol for a randomised controlled trial
BACKGROUND: Despite the clear harm associated with smoking tobacco, many people with smoking-related chronic diseases or serious mental illnesses (SMI) are unwilling or unable to stop smoking. In many cases, these smokers have tried and exhausted all methods to stop smoking and yet clinicians are repeatedly mandated to offer them during routine consultations. Providing nicotine through electronic cigarettes (e-cigarettes) may reduce the adverse health consequences associated with tobacco smoking, but these are not currently offered. The aim of this study is to examine the feasibility, acceptability and effectiveness of general practitioners (GPs) and nurses delivering a brief advice intervention on e-cigarettes and offering an e-cigarette starter pack and patient support resources compared with standard care in smokers with smoking-related chronic diseases or SMI who are unwilling to stop smoking. METHODS/DESIGN: This is an individually randomised, blinded, two-arm trial. Smokers with a smoking-related chronic condition or SMI with no intention of stopping smoking will be recruited through primary care registers. Eligible participants will be randomised to one of two groups if they decline standard care for stopping smoking: a control group who will receive no additional support beyond standard care; or an intervention group who will receive GP or nurse-led brief advice about e-cigarettes, an e-cigarette starter pack with accompanying practical support booklet, and telephone support from experienced vapers and online video tutorials. The primary outcome measures will be smoking reduction, measured through changes in cigarettes per day and 7-day point-prevalence abstinence at 2 months. Secondary outcomes include smoking reduction, 7-day point-prevalence abstinence and prolonged abstinence at 8 months. Other outcomes include patient recruitment and follow-up, patient uptake and use of e-cigarettes, nicotine intake, contamination of randomisation and practitioner adherence to the delivery of the intervention. Qualitative interviews will be conducted in a subsample of practitioners, patients and the vape team to garner their reactions to the programme. DISCUSSION: This is the first randomised controlled trial to investigate whether e-cigarette provision alongside a brief intervention delivered by practitioners leads to reduced smoking and abstinence among smokers with smoking-related chronic diseases or SMI. TRIAL REGISTRATION: ISRCTN registry, ISRCTN59404712. Registered 28/11/17
The social patterning of risk factors for noncommunicable diseases in five countries: evidence from the modeling the epidemiologic transition study (METS)
In situ oxygen-isotope, major-, and trace-element constraints on the metasomatic modification and crustal origin of a diamondiferous eclogite from Roberts Victor, Kaapvaal Craton
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