Science.gov

Sample records for continents

  1. A continent ileostomy device.

    PubMed Central

    Pemberton, J H; van Heerden, J A; Beart, R W; Kelly, K A; Phillips, S F; Taylor, B M

    1983-01-01

    The feasibility of achieving fecal continence by mechanical occlusion of an end-ileostomy is explored. Accordingly, progressive stomal occlusion with an indwelling occluding device was evaluated in four healthy patients with Brooke ileostomies. Pre-occlusion clinical and physiologic tests were done, including fat balance, intestinal transit time, ileal motility and absorption, ileal compliance, ileal radiography, and ileoscopy. Progressive stomal occlusion was then employed until periods of occlusion of 5 to 8 hours were achieved after 10 to 16 weeks. Pre-occlusion tests were then repeated. Patients mastered use of the occluding device rapidly, and the device achieved reliable stomal continence in each patient. Whereas ileal capacity was small initially, intermittent occlusion resulted in a large, capacious ileal reservoir. Fasting ileal motility was increased slightly by stomal occlusion, although intestinal transit during feeding was not altered. Also, ileal absorption of glucose, electrolytes, vitamin B-12, and fat were not changed, and ileal mucosa at the site of occlusion remained intact endoscopically. The authors concluded that chronic intermittent occlusion of a Brooke ileostomy with an indwelling stomal device achieved enteric continence without impairing intestinal function. Images Fig. 1. Fig. 4. PMID:6847281

  2. Continents and Earth's rotational stability

    NASA Astrophysics Data System (ADS)

    Rose, I.; Buffett, B. A.

    2014-12-01

    Continents strongly constrain the planform of the mantle convection/plate tectonic system. They impose long wavelength structure on surface velocities and tend to collect subduction zones around their margins . Additionally, they may affect the ability of the underlying mantle to effectively cool, which would create persistent temperature gradients between subcontinental and suboceanic mantle. These effects will change the moment of inertia of the planet and may control its rotational dynamics. Configurations of the continents have been implicated for both Earth's apparent Cenozoic rotational stability as well as its potential for large scale true polar wander deeper in its past. Here we present investigations into how continents can affect Earth's long term rotational stability. We have developed a version of the mantle convection code Aspect with a free outer surface, allowing for isostatically compensated continents and dynamic topography due to plumes and slabs. This allows us to self-consistently calculate moment of inertia anomalies in mantle convection models with surface continents and lateral viscosity variations. We explore different surface fractions of continental material as well as different mantle viscosity structures to identify when continents have a controlling influence. Finally, we discuss implications for Earth history, during which both continental mass and mantle viscosity may have changed significantly.

  3. Mountain building processes during continent continent collision in the Uralides

    NASA Astrophysics Data System (ADS)

    Brown, D.; Juhlin, C.; Ayala, C.; Tryggvason, A.; Bea, F.; Alvarez-Marron, J.; Carbonell, R.; Seward, D.; Glasmacher, U.; Puchkov, V.; Perez-Estaun, A.

    2008-08-01

    Since the early 1990's the Paleozoic Uralide Orogen of Russia has been the target of a significant research initiative as part of EUROPROBE and GEODE, both European Science Foundation programmes. One of the main objectives of these research programmes was the determination of the tectonic processes that went into the formation of the orogen. In this review paper we focus on the Late Paleozoic continent-continent collision that took place between Laurussia and Kazakhstania. Research in the Uralides was concentrated around two deep seismic profiles crossing the orogen. These were accompanied by geological, geophysical, geochronological, geochemical, and low-temperature thermochronological studies. The seismic profiles demonstrate that the Uralides has an overall bivergent structural architecture, but with significantly different reflectivity characteristics from one tectonic zone to another. The integration of other types of data sets with the seismic data allows us to interpret what tectonic processes where responsible for the formation of the structural architecture, and when they were active. On the basis of these data, we suggest that the changes in the crustal-scale structural architecture indicate that there was significant partitioning of tectonothermal conditions and deformation from zone to zone across major fault systems, and between the lower and upper crust. Also, a number of the structural features revealed in the bivergent architecture of the orogen formed either in the Neoproterozoic or in the Paleozoic, prior to continent-continent collision. From the end of continent-continent collision to the present, low-temperature thermochronology suggests that the evolution of the Uralides has been dominated by erosion and slow exhumation. Despite some evidence for more recent topographic uplift, it has so far proven difficult to quantify it.

  4. Traveling the Continents and Cruising the Oceans.

    ERIC Educational Resources Information Center

    Slack, Glenda

    Elementary school students learn about the continents and the oceans by completing a variety of activities, games, and puzzles. Students learn to spell the names of the oceans and continents; recognize the locations, sizes, and shapes of the continents; and use directions on maps by completing a pretest, word searches, mazes, crossword puzzles,…

  5. The mechanism of continence after posterior urethroplasty

    PubMed Central

    Bagga, Herman S.; Angermeier, Kenneth W.

    2015-01-01

    The standard of care after a pelvic fracture urethral injury is a repair via a one-stage anastomotic posterior urethroplasty using a step-wise perineal approach. The initial injury, immediate postoperative management, and surgical repair can all affect urinary continence in these patients. Proximal continence mechanisms, particularly the bladder neck, are particularly important in maintaining urinary continence in these patients. Patients with bladder neck dysfunction should be counselled about the greater risk of urinary incontinence. PMID:26019981

  6. Promoting continence in women following childbirth.

    PubMed

    Steen, Mary

    Continence in women during pregnancy and following childbirth is an important issue that needs to be managed appropriately. Urinary and bowel problems can have numerous negative physical and psychological consequences, and women may be too embarrassed to seek help. Healthcare professionals need to encourage and support women to identify any changes in their normal bowel and bladder habits. They also need to have knowledge of the anatomy and physiology of the urinary, reproductive and digestive systems to understand how continence may be affected during pregnancy and following childbirth. PMID:24003819

  7. African Universities Tackle the Continent's Agricultural Crisis

    ERIC Educational Resources Information Center

    Lindow, Megan

    2009-01-01

    Pests, population growth, and depleted soil have wreaked havoc on agriculture in Africa, so universities across the continent are rethinking how they teach the topic. Some African universities have been building their own networks and pooling their limited resources to train more agricultural scientists and improve their responsiveness to the…

  8. Understanding Barriers to Continence Care in Institutions

    ERIC Educational Resources Information Center

    Tannenbaum, Cara; Labrecque, Danielle; Lepage, Christiane

    2005-01-01

    This work seeks to identify factors that facilitate or diminish care-providers' propensity to improve continence care in long-term care (LTC) settings. We conducted a cross-sectional qualitative study using focus group methodology in four long-term care institutions in Montreal, QC. Forty-two nurses, nursing assistants, and orderlies caring for…

  9. Spreading continents kick-started plate tectonics.

    PubMed

    Rey, Patrice F; Coltice, Nicolas; Flament, Nicolas

    2014-09-18

    Stresses acting on cold, thick and negatively buoyant oceanic lithosphere are thought to be crucial to the initiation of subduction and the operation of plate tectonics, which characterizes the present-day geodynamics of the Earth. Because the Earth's interior was hotter in the Archaean eon, the oceanic crust may have been thicker, thereby making the oceanic lithosphere more buoyant than at present, and whether subduction and plate tectonics occurred during this time is ambiguous, both in the geological record and in geodynamic models. Here we show that because the oceanic crust was thick and buoyant, early continents may have produced intra-lithospheric gravitational stresses large enough to drive their gravitational spreading, to initiate subduction at their margins and to trigger episodes of subduction. Our model predicts the co-occurrence of deep to progressively shallower mafic volcanics and arc magmatism within continents in a self-consistent geodynamic framework, explaining the enigmatic multimodal volcanism and tectonic record of Archaean cratons. Moreover, our model predicts a petrological stratification and tectonic structure of the sub-continental lithospheric mantle, two predictions that are consistent with xenolith and seismic studies, respectively, and consistent with the existence of a mid-lithospheric seismic discontinuity. The slow gravitational collapse of early continents could have kick-started transient episodes of plate tectonics until, as the Earth's interior cooled and oceanic lithosphere became heavier, plate tectonics became self-sustaining. PMID:25230662

  10. Global anisotropy and the thickness of continents.

    PubMed

    Gung, Yuancheng; Panning, Mark; Romanowicz, Barbara

    2003-04-17

    For decades there has been a vigorous debate about the depth extent of continental roots. The analysis of heat-flow, mantle-xenolith and electrical-conductivity data all indicate that the coherent, conductive part of continental roots (the 'tectosphere') is at most 200-250 km thick. Some global seismic tomographic models agree with this estimate, but others suggest that a much thicker zone of high velocities lies beneath continental shields, reaching a depth of at least 400 km. Here we show that this disagreement can be reconciled by taking into account seismic anisotropy. We show that significant radial anisotropy, with horizontally polarized shear waves travelling faster than those that are vertically polarized, is present under most cratons in the depth range 250-400 km--similar to that found under ocean basins at shallower depths of 80-250 km. We propose that, in both cases, the anisotropy is related to shear in a low-viscosity asthenospheric channel, located at different depths under continents and oceans. The seismically defined 'tectosphere' is then at most 200-250 km thick under old continents. The 'Lehmann discontinuity', observed mostly under continents at about 200-250 km, and the 'Gutenberg discontinuity', observed under oceans at depths of about 60-80 km, may both be associated with the bottom of the lithosphere, marking a transition to flow-induced asthenospheric anisotropy. PMID:12700758

  11. 21 CFR 876.5320 - Nonimplanted electrical continence device.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... vagina and used to stimulate the muscles of the pelvic floor to maintain urinary or fecal continence... nonimplanted electrical continence device and the powered vaginal muscle stimulator for therapeutic use (§...

  12. 21 CFR 876.5320 - Nonimplanted electrical continence device.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... vagina and used to stimulate the muscles of the pelvic floor to maintain urinary or fecal continence... nonimplanted electrical continence device and the powered vaginal muscle stimulator for therapeutic use (§...

  13. 21 CFR 876.5320 - Nonimplanted electrical continence device.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... vagina and used to stimulate the muscles of the pelvic floor to maintain urinary or fecal continence... nonimplanted electrical continence device and the powered vaginal muscle stimulator for therapeutic use (§...

  14. 21 CFR 876.5320 - Nonimplanted electrical continence device.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... vagina and used to stimulate the muscles of the pelvic floor to maintain urinary or fecal continence... nonimplanted electrical continence device and the powered vaginal muscle stimulator for therapeutic use (§...

  15. 21 CFR 876.5320 - Nonimplanted electrical continence device.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... vagina and used to stimulate the muscles of the pelvic floor to maintain urinary or fecal continence... nonimplanted electrical continence device and the powered vaginal muscle stimulator for therapeutic use (§...

  16. Lithospheric properties on a continent-continent collisional scenario: the Pyrenean range

    NASA Astrophysics Data System (ADS)

    Ledo, Juanjo; Campanyà, Joan; Fullea, Javier; Queralt, Pilar; Marcuello, Alex; Liesa, Montse; Muñoz, Josep Anton

    2013-04-01

    Continent-continent collision is a fundamental tectonic process that plays a primary role in the development and evolution of continents. The Pyrenees resulted from the continental collision between the Iberian and European plates during the Alpine orogeny. This mountain range offers an unique opportunity to study orogenic processes due to the well constrained geological evolution and the significant amount of geophysical data available. In this paper present a joint quantitative interpretation of the available geophysical and geochemical data along two transects across the Pyrenean orogeny. These new results confirm the previous hypothesis of partial melting of the subducted Iberian lower crust and constrain the depth of the lithosphere-astenosphere boundary (LAB). The bulk mantle electrical conductivity and seismic velocities have been modelled using the software package LitMod, which allows for coupled petrological and geophysical modeling of the lithosphere and sublithospheric upper mantle within an internally consistent thermodynamic-geophysical framework.

  17. Cystic fibrosis on the African continent.

    PubMed

    Stewart, Cheryl; Pepper, Michael S

    2016-07-01

    Cystic fibrosis (CF; OMIM 219700) is a life-shortening and costly autosomal recessive disease that has been most extensively studied in individuals of Caucasian descent. There is ample evidence, however, that it also affects other ethnicities. In Africa there have been several reports of CF, but there has been no concerted effort toward establishing the molecular epidemiology of this disease on the continent, which is the first step toward outlining a public health strategy to effectively address the needs of these patients. A literature search revealed reports from only 12 of the 54 African states on the molecular analysis of the mutations present in suspected CF patients, resulting in the identification of 79 mutations. Based on previous functional investigations, 39 of these cause CF, 10 are of varying clinical consequence, 4 have no associated evidence regarding whether they cause CF, 4 are synonymous, 5 are novel, and 21 are unique to Africa. We propose that CF be more thoroughly investigated on the continent to ensure that the public health needs of African CF patients-both those in Africa and those of African descent living elsewhere-are met.Genet Med 18 7, 653-662. PMID:26656651

  18. Imaging Lithospheric Structure beneath the Indian continent

    NASA Astrophysics Data System (ADS)

    Maurya, S.; Montagner, J. P.; Mangalampally, R. K.; Stutzmann, E.; Burgos, G.; Kumar, P.; Davuluri, S.

    2015-12-01

    The lithospheric structure and thickness to the LAB are the most debated issues, especially beneath continents. In this context, the structure and thickness of the Indian lithosphere has been controversial. Paleomagnetic data reveals that the Indian continent moved northwards at exceptionally high speeds (18-20 cm/year) and subsequently slowed down to 4-5 cm/year after its collision with Asia ≈40 Myr ago. This super mobility has been explained by an unusually thin Indian lithosphere (≈100 km; Kumar et al., 2007) in contradiction with the thick lithosphere that commonly underlies old cratonic nuclei. It is pertinent to note that the thermobarometric estimates on the ultramafic xenoliths from 65 Myr kimberlites of the Central India (Babu et al. 2009) suggest an approximately 175 km thick lithosphere. Also, recent results of P and S wave travel time tomography of India suggest that the lithospheric roots are not uniformly thick on a regional scale. Although high velocity roots typical of Precambrian shields are preserved beneath a few cratons of the Indian shield, they seem to have suffered attrition, in the plume ravaged regions like the NDVP and the Southern SGT (Singh et al., 2014). We assembled a new massive surface wave database towards obtaining 3D isotropic and anisotropic models for the Indian sub-continent, using surface waves. This necessitated processing of data from more than 500 seismic broadband stations across India and surrounding regions. Surface waves group and phase dispersion measurements are performed in a broad frequency range (16-250s). Our phase velocity anomaly maps recover most of the known geological structures. The cratons are associated with high velocity (4-6%) anomalies till 200 sec, with the WDC being faster than the EDC. Slow velocities in NW India and very high velocity anomalies (6-8%) beneath the central part of the Indo-Gangetic plains are possibly associated with the subducting Indian lithosphere. The LAB depths inferred from

  19. The ribbon continent of northwestern South America

    NASA Astrophysics Data System (ADS)

    Altamira-Areyan, Armando

    The tectonic structure of the Plate Boundary Zone (PBZ) between the Caribbean Plate (CARIB) and the South American Plate (SOAM) is interpreted using models that require CARIB motion from the Pacific into the Atlantic. Those models can be subdivided into: (1) those in which the island arc rocks that are now in the CARIB-SOAM PBZ have collided with the northern South America margin, either obliquely or directly during the Cretaceous or during the Cenozoic, and (2) those in which the island arc rocks now in the CARIB-SOAM PBZ collided with the west coast of South America during the Cretaceous and were transferred to the northern margin by transform motion during the Cenozoic. Magnetic anomalies were first rotated in the Central and South Atlantic, holding Africa fixed to establish how much NOAM had converged on SOAM during the Cenozoic. WSW convergence was discovered to have been accommodated in the northern boundary of the CARIB. There is no evidence of convergence in the form of Cenozoic island arc igneous rocks on the north coast of South America. Those results are consistent only with models of Class (2) that call for transform movement of material that had collided with the west coast of South America along the CARIB-SOAM PBZ on the northern margin of South America. 40Ar/39Ar ages of island arc rocks from northern Venezuela were found to be older than ca 70 Ma, which is consistent with a requirement of models of Class (2) that those rocks are from an island arc which collided with the west coast of South America during Cretaceous times. Testing that conclusion using data from Ecuador, Colombia, Venezuela, the Netherlands Antilles, Trinidad and Tobago has led to the construction of a new ribbon continent model of the northwestern Cordillera of South America. Because the part of the ribbon continent on the north coast of South America has been experiencing substantial deformation in the Maracaibo block during the past 10 m.y., structures in that body have had to be

  20. Young Africans Tackle Their Continent's Environmental Issues

    NASA Astrophysics Data System (ADS)

    Olwoch, Jane Mukarugwiza

    2008-11-01

    Young African Scientists Session at the Fourth International Geosphere-Biosphere Programme Congress; Cape Town, South Africa, 7 May 2008; Africa is often described as a unique and diverse continent. This is reflected in its biodiversity, economic and social circumstances, and diversity in culture and environment. The Young African Scientists (YAS) session at the International Geosphere-Biosphere Programme Congress was one of the congress's highlights. Global environmental change research in Africa was presented to an audience that included visiting international and national scientists, policy makers, and a group of schoolchildren. From the uniqueness of Africa's paleoclimate to the diversity and complexity of current and future impacts of environmental change on Africa, the session not only provided an overview of current projects but also highlighted the problems that are intertwined with poverty. This session was sponsored by the Global Change System for Analysis, Research, and Training (START).

  1. OxyContin: Prescription Drug Abuse. CSAT Advisory.

    ERIC Educational Resources Information Center

    Substance Abuse and Mental Health Services Administration (DHHS/PHS), Rockville, MD. Center for Substance Abuse Treatment.

    Recently, the media have issued numerous reports about the apparent increase in OxyContin abuse and addiction. OxyContin has been heralded as a miracle drug that allows patients with chronic pain to resume a normal life. It has also been called pharmaceutical heroin and is thought to have been responsible for a number of deaths and robberies in…

  2. 21 CFR 876.5030 - Continent ileostomy catheter.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Continent ileostomy catheter. 876.5030 Section 876.5030 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Therapeutic Devices § 876.5030 Continent...

  3. 21 CFR 876.5270 - Implanted electrical urinary continence device.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Implanted electrical urinary continence device. 876.5270 Section 876.5270 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Therapeutic Devices § 876.5270 Implanted electrical urinary continence device....

  4. 21 CFR 876.5270 - Implanted electrical urinary continence device.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... Implanted electrical urinary continence device. (a) Identification. An implanted electrical urinary device is a device intended for treatment of urinary incontinence that consists of a receiver implanted in... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Implanted electrical urinary continence...

  5. 21 CFR 876.5270 - Implanted electrical urinary continence device.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... Implanted electrical urinary continence device. (a) Identification. An implanted electrical urinary device is a device intended for treatment of urinary incontinence that consists of a receiver implanted in... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Implanted electrical urinary continence...

  6. 21 CFR 876.5030 - Continent ileostomy catheter.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Continent ileostomy catheter. 876.5030 Section 876.5030 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Therapeutic Devices § 876.5030 Continent...

  7. 21 CFR 876.5310 - Nonimplanted, peripheral electrical continence device.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ....5310 Nonimplanted, peripheral electrical continence device. (a) Identification. A nonimplanted, peripheral electrical continence device is a device that consists of an electrode that is connected by an electrical cable to a battery-powered pulse source. The electrode is placed onto or inserted into the body...

  8. 21 CFR 876.5310 - Nonimplanted, peripheral electrical continence device.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ....5310 Nonimplanted, peripheral electrical continence device. (a) Identification. A nonimplanted, peripheral electrical continence device is a device that consists of an electrode that is connected by an electrical cable to a battery-powered pulse source. The electrode is placed onto or inserted into the body...

  9. Doug Nelson's Contributions to our Understanding of Young Continent-Continent Collisions

    NASA Astrophysics Data System (ADS)

    Klemperer, S. L.; Brown, L. D.; Jones, A. G.

    2002-12-01

    K. Douglas Nelson, Department Chair and Jessie Page Heroy Professor of Earth Sciences at Syracuse University, died suddenly of heart failure on August 17th, 2002, age 49. At the time of his death he was at the heights of an increasingly distinguished career, and had, just prior to his death, agreed to be an invited speaker in this session of the 2002 Fall AGU meeting. Doug began his professional career as a field structural geologist, writing his PhD on the Newfoundland Appalachians, and as a post-doc in South Island, New Zealand. From there he went to Cornell University to join COCORP; he learned to interpret deep seismic reflection data and became hooked on the value of geophysics to the study of large-scale processes in mountain belts. He became one of the proponents of taking the COCORP methodology overseas, to the world's type example of young, continent-continent collisions, the Himalaya. For 10 years from 1992, by now a faculty member at Syracuse, Doug provided operational and intellectual leadership to the INDEPTH program (International Deep Profiling of Tibet and the Himalaya). His talk in this session would undoubtedly have focused on our new understanding of Tibet that resulted in large part from the work that he led and supervised. From the initial conception of INDEPTH as a single reflection profile across Earth's highest mountain range and largest plateau, the program grew through three major stages to encompass a full range of geophysical and geological surveys in a transect that now reaches from the High Himalaya across Tibet. Doug more than anyone was the enthusiastic integrator in the large multi-national group of investigators (from the U.S., China, Canada and Germany), not bound by a single technique, and best able to synthesize the seemingly disparate observations from all the techniques. In recent years he was particularly interested in the combination of magneto-telluric with seismic results to better constrain interpretation of deep geology

  10. Multimetric Macroinvertebrate Indices for Mid-continent US Great Rivers

    EPA Science Inventory

    We developed a set of great river macroinvertebrate indices of condition (GRMICs) for the mid-continent great rivers. We used a multiscale (site, reach, landscape) multimetric abiotic stressor gradient to select macroinvertebrate assemblage metrics sensitive to human disturbance ...

  11. 21 CFR 876.5270 - Implanted electrical urinary continence device.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... (premarket approval). (c) Date PMA or notice of completion of a PDP is required. A PMA or a notice of..., 1976. Any other implanted electrical urinary continence device shall have an approved PMA or a...

  12. 21 CFR 876.5270 - Implanted electrical urinary continence device.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... (premarket approval). (c) Date PMA or notice of completion of a PDP is required. A PMA or a notice of..., 1976. Any other implanted electrical urinary continence device shall have an approved PMA or a...

  13. Wrench faulting initiated by continent-continent collision between the Eratosthenes Seamount and Cyprus

    NASA Astrophysics Data System (ADS)

    Ehrhardt, A.; Schnabel, M.; Damm, V.; Huebscher, C. P.

    2010-12-01

    The Eratosthenes Seamount (ESM), located in the Eastern Mediterranean south of Cyprus, is considered to represent a continental fragment originating from the former African-Arabian continental margin. In the late Miocene the subduction of the African-Arabian Plate below the Anatolian Plate turned to continent-continent collision when the ESM collided with the island of Cyprus. This altered the tectonic pattern of the entire Eastern Mediterranean. Since the ESM blocks the northward drift of the African Plate south of Cyprus, the northward motion of the African-Arabian Plate (around 1cm/year) has to be compensated along wrench faults. The Baltim Hecateus Line (BHL) separates the ESM on its eastern side from the deep Levantine Basin. The BHL formed as an extensional fault system during the Triassic formation of the Levatine Basin. During the Upper Cretaceous and Eocene so called Syrian Arc inversion the BHL was reactivated. A set of recent multichannel seismic 2D lines (MCS), acquired with the R/V Maria S. Merian (MSM14-2) in 2010, will be presented here. The NW-SE trending lines show a transformal to transpressional nature of the Baltim Hecateus Line. We propose that the BHL converted to a transform fault during the incipient collision of the ESM with the island of Cyprus in order to compensate the northward motion of the African-Arabian Plate. At the eastern rim of the ESM the BHL continues beneath a prominent bathymetric escarpment. Whereas the escarpment matches the trace of the BHL it is covered below the thick Messinian Evaporites south and north of the ESM. Owing to the ductile properties of salt the Messinian evaporites decouple the sub salt sediments from the supra salt sediments. As a result no direct observations of the BHL are possible. However, seismic imaging reveals thrust folds at the western side of the Levantine Basin pointing to a transpressional nature of the BHL. The overlying sediments are thinned as a reaction to the transform motion. Due to a

  14. Predictors of early continence following robot-assisted radical prostatectomy

    PubMed Central

    Lavigueur-Blouin, Hugo; Noriega, Alina Camacho; Valdivieso, Roger; Hueber, Pierre-Alain; Bienz, Marc; Alhathal, Naif; Latour, Mathieu; Trinh, Quoc-Dien; El-Hakim, Assaad; Zorn, Kevin C.

    2015-01-01

    Introduction: Functional outcomes after robot-assisted radical prostatectomy (RARP) greatly influence patient quality of life. Data regarding predictors of early continence, especially 1 month following RARP, are limited. Previous reports mainly address immediate or 3-month postoperative continence rates. We examine preoperative predictors of pad-free continence recovery at the first follow-up visit 1 month after RARP. Methods: Between January 2007 and January 2013, preoperative and follow-up data were prospectively collected for 327 RARP patients operated on by 2 fellowship-trained surgeons (AEH and KCZ). Patient and operative characteristics included age, body mass index (BMI), staging, preoperative prostate-specific antigen (PSA), prostate weight, International Prostate Symptom Score (IPSS), Sexual Health Inventory for Men (SHIM) score and type of nerve-sparing performed. Continence was defined by 0-pad usage at 1 month follow-up. Univariate and multivariate logistic regression models were used to assess for predictors of early continence. Results: Overall, 44% of patients were pad-free 1 month post-RARP. In multivariate regression analysis, age (odds ratio [OR] 0.946, confidence interval [CI] 95%: 0.91, 0.98) and IPSS (OR: 0.953, CI 95%: 0.92, 0.99) were independent predictors of urinary continence 1 month following RARP. Other variables (BMI, staging, preoperative PSA, SHIM score, prostate weight and type of nerve-sparing) were not statistically significant predictors of early continence. Limitations of this study include missing data for comorbidities, patient use of pelvic floor exercises and patient maximal activity. Moreover, patient-reported continence using a 0-pad usage definition represents a semiquantitative and subjective measurement. Conclusion: In a broad population of patients who underwent RARP at our institution, 44% of patients were pad-free at 1 month. Age and IPSS were independent predictors of early continence after surgery. Men of advanced

  15. Anatomic basis for the continence-preserving radical retropubic prostatectomy.

    PubMed

    Steiner, M S

    2000-02-01

    The technique of continence-preserving anatomic radical retropubic prostatectomy focuses on the preservation of the following anatomic components of the external striated urethral sphincteric complex: (1) the entire circumference of the rhabdosphincter musculature, (2) the periurethral fascial investments (the pubourethral ligaments anterolaterally and median fibrous raphe posteriorly), and (3) the innervation of both the rhabdosphincter by way of the intrapelvic branch of the pudendal nerve (somatic) and the mucosal and smooth muscle components by way of the urethral branch of the inferior hypogastric plexus (autonomic). The clinical impact of preserving the external striated urethral sphincter and its innervation by performing a continence preserving anatomic retropubic prostatectomy is a shorter time to achieve urinary continence. PMID:10719925

  16. A Geological Model for the Evolution of Early Continents (Invited)

    NASA Astrophysics Data System (ADS)

    Rey, P. F.; Coltice, N.; Flament, N. E.; Thébaud, N.

    2013-12-01

    Geochemical probing of ancient sediments (REE in black shales, strontium composition of carbonates, oxygen isotopes in zircons...) suggests that continents were a late Archean addition at Earth's surface. Yet, geochemical probing of ancient basalts reveals that they were extracted from a mantle depleted of its crustal elements early in the Archean. Considerations on surface geology, the early Earth hypsometry and the rheology and density structure of Archean continents can help solve this paradox. Surface geology: The surface geology of Archean cratons is characterized by thick continental flood basalts (CFBs, including greenstones) emplaced on felsic crusts dominated by Trondhjemite-Tonalite-Granodiorite (TTG) granitoids. This simple geology is peculiar because i/ most CFBs were emplaced below sea level, ii/ after their emplacement, CFBs were deformed into relatively narrow, curviplanar belts (greenstone basins) wrapping around migmatitic TTG domes, and iii/ Archean greenstone belts are richly endowed with gold and other metals deposits. Flat Earth hypothesis: From considerations on early Earth continental geotherm and density structure, Rey and Coltice (2008) propose that, because of the increased ability of the lithosphere to flow laterally, orogenic processes in the Archean produced only subdued topography (continents, Flament et al. (2008) proposed a theory for the hypsometry of the early Earth showing that, until the late Archean, most continents were flooded and Earth was largely a water world. From this, a model consistent with many of the peculiar attributes of Archean geology, can be proposed: 1/ Continents appeared at Earth's surface at an early stage during the Hadean/Archean. However, because they were i/ covered by continental flood basalts, ii/ below sea level, and iii/ deprived of modern-style mountain belts and orogenic plateaux, early felsic

  17. Continent urinary diversion using an artificial urinary sphincter.

    PubMed

    Mitrofanoff, P; Bonnet, O; Annoot, M P; Bawab, F; Grise, P

    1992-07-01

    We report a new and simplified method of continent urinary diversion employing a modified AMS 800 artificial urinary sphincter (AUS). Our aim in using this artificial valve is to make a stoma continent, while allowing intermittent catheterisation. The AMS 800 pump is replaced by a subcutaneous injection port. This allows, by direct puncture, the accurate setting of the closing pressure by varying the volume of the intra-prosthetic liquid, with subsequent adjustment of this pressure as necessary. The cuff is placed on the subcutaneous part of the intestinal loop diversion. The pressure-regulating balloon is implanted within the area of abdominal pressure, retroperitoneally. After first confirming the efficacy of the system in 3 dogs, the device was placed in 2 patients. The first had a neuropathic bladder treated initially by enterocystoplasty with an appendicocutaneous stoma. Secondary leakage was subsequently controlled by placement of the device, with continuing excellent results at 32 months. The second patient was a girl in whom a urogenital rhabdomyosarcoma had been treated by anterior exenteration, radiotherapy and a sigmoid conduit diversion. This was subsequently converted to a continent reservoir by simple augmentation of the conduit and placement of the device, with a good result being maintained after a follow-up of 20 months. These two cases illustrate the best indications for this procedure, namely primary or secondary leakage from a supposedly continent urinary diversion, and conversion of a freely draining conduit into a continent reservoir. Although long-term results are still pending, our experience thus far encourages us to recommend this technique as a simple means of achieving a continent urinary diversion. PMID:1638370

  18. The Eastern Tennessee Seismic Zone: Reactivation of an Ancient Continent-Continent Suture Zone

    NASA Astrophysics Data System (ADS)

    Powell, C. A.

    2014-12-01

    The eastern Tennessee seismic zone (ETSZ) may represent reactivation of an ancient shear zone that accommodated left-lateral, transpressive motion of the Amazon craton during the Grenville orogeny. Several different lines of evidence support this concept including velocity models for the crust, earthquake hypocenter alignments, focal mechanism solutions, potential field anomalies, paleomagnetic pole positions, and isotopic geochemical studies. The ETSZ trends NE-SW for about 300 km and displays remarkable correlation with the prominent New York - Alabama (NY-AL) aeromagnetic lineament. Vp and Vs models for the crust derived from a local ETSZ earthquake tomography study reveal the presence of a narrow, NE-SW trending, steeply dipping zone of low velocities that extends to a depth of at least 24 km and is associated with the vertical projection of the NY-AL aeromagnetic lineament. The low velocity zone is interpreted as a major basement fault. The recent Mw 4.2 Perry County eastern Kentucky earthquake occurred north of the ETSZ but has a focal depth and mechanism that are similar to those for ETSZ earthquakes. We investigate the possibility that the proposed ancient shear zone extends into eastern Kentucky using Bouguer and aeromagnetic maps. The southern end of the ETSZ is characterized by hypocenters that align along planes dipping at roughly 45 degrees and focal mechanisms that contain large normal faulting components. The NY-AL aeromagnetic lineament also changes trend in the southern end of the ETSZ and the exact location of the lineament is ambiguous. We suggest that the southern portion of the ETSZ involves reactivation of reverse faults (now as normal faults) that mark the ancient transition between a collisional to a more transpressive boundary between Amazonia and Laurentia during the formation of the super continent Rodinia.

  19. Continent X: The Geopolitical Lesson of Size, Shape, and Location.

    ERIC Educational Resources Information Center

    Byklum, Daryl

    1992-01-01

    Offers suggestions for teaching high school students about the relevance of a nation's size, shape, and location to its geopolitical influence. Includes a map of and suggested teaching procedures concerning the hypothetical "Continent X" and its five component nations. Suggests follow-up topics. (SG)

  20. Regulating continent growth and composition by chemical weathering

    USGS Publications Warehouse

    Lee, C.-T.A.; Morton, D.M.; Little, M.G.; Kistler, R.; Horodyskyj, U.N.; Leeman, W.P.; Agranier, A.

    2008-01-01

    Continents ride high above the ocean floor because they are underlain by thick, low-density, Si-rich, and Mg-poor crust. However, the parental magmas of continents were basaltic, which means they must have lost Mg relative to Si during their maturation into continents. Igneous differentiation followed by lower crustal delamination and chemical weathering followed by subduction recycling are possible solutions, but the relative magnitudes of each process have never been quantitatively constrained because of the lack of appropriate data. Here, we show that the relative contributions of these processes can be obtained by simultaneous examination of Mg and Li (an analog for Mg) on the regional and global scales in arcs, delaminated lower crust, and river waters. At least 20% of Mg is lost from continents by weathering, which translates into >20% of continental mass lost by weathering (40% by delamination). Chemical weathering leaves behind a more Si-rich and Mg-poor crust, which is less dense and hence decreases the probability of crustal recycling by subduction. Net continental growth is thus modulated by chemical weathering and likely influenced by secular changes in weathering mechanisms. ?? 2008 by The National Academy of Sciences of the USA.

  1. Children's Estimations of the Sizes of the Continents.

    ERIC Educational Resources Information Center

    Wiegand, Patrick; Stiell, Bernadette

    1996-01-01

    Examines children's knowledge and understanding of global spatial relationships. Utilizing cut-outs of continents to estimate their size in relation to Europe, the students consistently underestimated the size of Asia and overestimated Australia. Possible reasons for this are discussed and teaching approaches suggested. (MJP)

  2. 21 CFR 876.5310 - Nonimplanted, peripheral electrical continence device.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Nonimplanted, peripheral electrical continence device. 876.5310 Section 876.5310 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Therapeutic Devices §...

  3. Petroleum Technology Transfer Council boosts North Mid-continent technology

    SciTech Connect

    Lyle, D.

    1995-10-01

    The Kansas Tertiary Oil Recovery Project served as one of the primary models for the Petroleum Technology Transfer Council, so it`s fitting this series on regional applications should start with the North Mid-Continent organization. The technology transfer program is described.

  4. Regulating continent growth and composition by chemical weathering

    PubMed Central

    Lee, Cin-Ty Aeolus; Morton, Douglas M.; Little, Mark G.; Kistler, Ronald; Horodyskyj, Ulyana N.; Leeman, William P.; Agranier, Arnaud

    2008-01-01

    Continents ride high above the ocean floor because they are underlain by thick, low-density, Si-rich, and Mg-poor crust. However, the parental magmas of continents were basaltic, which means they must have lost Mg relative to Si during their maturation into continents. Igneous differentiation followed by lower crustal delamination and chemical weathering followed by subduction recycling are possible solutions, but the relative magnitudes of each process have never been quantitatively constrained because of the lack of appropriate data. Here, we show that the relative contributions of these processes can be obtained by simultaneous examination of Mg and Li (an analog for Mg) on the regional and global scales in arcs, delaminated lower crust, and river waters. At least 20% of Mg is lost from continents by weathering, which translates into >20% of continental mass lost by weathering (40% by delamination). Chemical weathering leaves behind a more Si-rich and Mg-poor crust, which is less dense and hence decreases the probability of crustal recycling by subduction. Net continental growth is thus modulated by chemical weathering and likely influenced by secular changes in weathering mechanisms. PMID:18362343

  5. 21 CFR 876.5310 - Nonimplanted, peripheral electrical continence device.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Nonimplanted, peripheral electrical continence device. 876.5310 Section 876.5310 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Therapeutic Devices §...

  6. Miocene sedimentation and subsidence during continent-continent collision, Bengal basin, Bangladesh

    NASA Astrophysics Data System (ADS)

    Uddin, Ashraf; Lundberg, Neil

    2004-02-01

    The Bengal basin, a complex foreland basin south of the eastern Himalayas, exhibits dramatic variability in Neogene sediment thickness that reflects a complicated depositional and tectonic history. This basin originally formed as a trailing margin SE of the Indian continental crust, complicated by convergence with Asia to the north and oblique convergence with Burma to the east. Newly compiled isopach data and previously reported seismic data show evidence of thickening of basin fill toward the south, opposite of the pattern typically seen in foreland basins. This is presumably due to sedimentary loading of voluminous deltaic sediments near the continent-ocean boundary and basinward downfaulting analogous to that in the Gulf of Mexico. Isopach data show that there is considerable vertical relief along the base of the Miocene stratigraphic sequence, probably due to down-to-the-basin faulting caused by focused deltaic sedimentation and associated crustal flexure. In contrast, when viewed in east-west profile, basin shape is more typical of a foreland basin, with strata thickening eastward toward the Indo-Burman ranges, which reflects east-west convergence with Southeast Asia. Comparison of the lateral and vertical extent of the Bhuban and Boka Bil Formations with the Bouguer anomaly map of Bangladesh suggests that considerable subsidence of the Sylhet trough (in the northeastern part of the Bengal basin), which has the lowest gravity value of the region, had not taken place by the end of the Miocene. This post-Miocene subsidence is attributed to tectonic loading from southward thrusting of the Shillong Plateau along the Dauki fault. Relatively uniform Miocene isopachs across the Sylhet trough confirm that this began in the Pliocene, consistent with results of recent research on sediment provenance. In the northwest, in the region south of the Siwalik foreland basin, continental crust has not as yet been loaded, allowing relatively little accommodation space for

  7. Madagascar: Heads It's a Continent, Tails It's an Island

    NASA Astrophysics Data System (ADS)

    de Wit, Maarten J.

    Neither geologists nor biologists have a definition that is capable of classifying Madagascar unambiguously as an island or a continent; nor can they incorporate Malagasy natural history into a single model rooted in Africa or Asia. Madagascar is a microcosm of the larger continents, with a rock record that spans more than 3000 million years (Ma), during which it has been united episodically with, and divorced from, Asian and African connections. This is reflected in its Precambrian history of deep crustal tectonics and a Phanerozoic history of biodiversity that fluctuated between cosmopolitanism and parochialism. Both vicariance and dispersal events over the past 90 Ma have blended a unique endemism on Madagascar, now in decline following rapid extinctions that started about 2000 years ago.

  8. The Continent-Ocean Boundary of the South China Sea

    NASA Astrophysics Data System (ADS)

    Wan, Ling; Yao, Bochu; Zhang, Huodai; Han, Bin

    2014-05-01

    The Continent-Ocean Boundary of the South China Sea Ling Wan Bochu Yao Huodai Zhang Bin Han (Guangzhou Marine Geological Survey, Guangzhou, China, 510760) The determination of the Continent-Ocean Boundary (COB) of the South China Sea (SCS) is a key issue related to fully understanding the rifted continental margins and evolutionof the SCS. But the COB of the SCS is highly variable in different ways by different researcher. In this paper, we investigate the boundary between the continental and oceanic crust of this basin mainly relied on the multiple-channel seismic profiles constrained by free air gravity anomaly and magnetic anomaly. Based on the synthesied gephysical interpretation the COB of the SCS is relocated. Furthermore, the COB patterns of the SCS are presented.

  9. Mid-Continent rift system - a frontier hydrocarbon province

    SciTech Connect

    Lee, C.K.; Kerr, S.D. Jr.

    1983-08-01

    Geophysical evidence in the Mid-Continent has led to delineation of a rift system active during the Proterozoic Y Era. The Mid-Continent rift system can be traced by the Mid-Continent gravity high and corresponding aeromagnetic anomaly signature from the surface exposure of the Keweenawan Supergroup in the Lake Superior basin southwest in the subsurface through Wisconsin, Minnesota, Iowa, Nebraska, and Kansas. The aeromagnetic anomaly signature of the rift trend discloses where these sediments have been preserved. Thick accumulations of upper Proterozoic sediments are indicated by both upward continuation of the aeromagnetic profiles across the rift trend and gravity models which incorporate: 1) a deep mafic body to create the narrow gravity high, 2) anomalously thick crust to account for the more regional gravity low, and 3) sedimentary accumulations on the Precambrian surface to explain the small-scale notches which occur within the narrow gravity high. Reflection seismic data are virtually unknown in the rift area; however, data recently acquired by COCORP across the southern end of the feature in Kansas provide evidence of thick stratified sequences in the rift valley. Studies of the East African rift have revealed that the tropical rift valley is an exceptionally fertile environment for deposition and preservation of kerogenous material. The Sirte, Suez, Viking, Dnieper-Donetz, and Tsaidam basins are just a few of the rift basins currently classed as giant producers. The existence of a rift basin trend with thick accumulations of preserved sediments, demonstrably organic rich, introduces the northern Mid-Continent US as a new frontier for hydrocarbon exploration.

  10. Mid-continent natural gas reservoirs and plays

    SciTech Connect

    Bebout, D.G. )

    1993-09-01

    Natural gas reservoirs of the mid-continent states of Oklahoma, Kansas, and Arkansas (northern part) have produced 103 trillion cubic ft (tcf) of natural gas. Oklahoma has produced the most, having a cumulative production of 71 tcf. The major reservoirs (those that have produced more than 10 billion ft[sup 3]) have been identified and organized into 28 plays based on geologic age, lithology, and depositional environment. The Atlas of Major Midcontinent Gas Reservoirs, published in 1993, provides the documentation for these plays. This atlas was a collaborative effort of the Gas Research Institute; Bureau of Economic Geology. The University of Texas at Austin; Arkansas Geological Commission; Kansas Geological survey; and Oklahoma Geological Survey. Total cumulative production for 530 major reservoirs is 66 tcf associated and nonassociated gas. Oklahoma has the highest production with 39 tcf from 390 major reservoirs, followed by Kansas with 26 tcf from 105 major reservoirs. Most of the mid-continent production is from Pennsylvanian (46%) and Permian (41%) reservoirs; Mississippian reservoirs account for 10% production, and lower Paleozoic reservoirs, 3%. The largest play by far is the Wolfcampian Shallow Shelf Carbonate-Hugoton Embayment play with 25 tcf cumulative production, most of which is from the Hugoton and Panoma fields in Kansas and Guymon-Hugoton gas area in Oklahoma. A total of 53% of the mid-continent gas production is from dolostone and limestone reservoirs; 39% is from sandstone reservoirs. The remaining 8% is from chert conglomerate and granite-wash reservoirs. Geologically based plays established from the distribution of major gas reservoirs provide important support for the extension of productive trends, application of new resource technology to more efficient field development, and further exploration in the mid-continent region.

  11. Extreme events in gross primary production: a characterization across continents

    NASA Astrophysics Data System (ADS)

    Zscheischler, J.; Reichstein, M.; Harmeling, S.; Rammig, A.; Tomelleri, E.; Mahecha, M. D.

    2014-06-01

    Climate extremes can affect the functioning of terrestrial ecosystems, for instance via a reduction of the photosynthetic capacity or alterations of respiratory processes. Yet the dominant regional and seasonal effects of hydrometeorological extremes are still not well documented and in the focus of this paper. Specifically, we quantify and characterize the role of large spatiotemporal extreme events in gross primary production (GPP) as triggers of continental anomalies. We also investigate seasonal dynamics of extreme impacts on continental GPP anomalies. We find that the 50 largest positive extremes (i.e., statistically unusual increases in carbon uptake rates) and negative extremes (i.e., statistically unusual decreases in carbon uptake rates) on each continent can explain most of the continental variation in GPP, which is in line with previous results obtained at the global scale. We show that negative extremes are larger than positive ones and demonstrate that this asymmetry is particularly strong in South America and Europe. Our analysis indicates that the overall impacts and the spatial extents of GPP extremes are power-law distributed with exponents that vary little across continents. Moreover, we show that on all continents and for all data sets the spatial extents play a more important role for the overall impact of GPP extremes compared to the durations or maximal GPP. An analysis of possible causes across continents indicates that most negative extremes in GPP can be attributed clearly to water scarcity, whereas extreme temperatures play a secondary role. However, for Europe, South America and Oceania we also identify fire as an important driver. Our findings are consistent with remote sensing products. An independent validation against a literature survey on specific extreme events supports our results to a large extent.

  12. Extreme events in gross primary production: a characterization across continents

    NASA Astrophysics Data System (ADS)

    Zscheischler, J.; Mahecha, M. D.; Harmeling, S.; Rammig, A.; Tomelleri, E.; Reichstein, M.

    2014-01-01

    Climate extremes can affect the functioning of terrestrial ecosystems, for instance via a reduction of the photosynthetic capacity or alterations of respiratory processes. Yet the dominant regional and seasonal effects of hydrometeorological extremes are still not well documented. Here we quantify and characterize the role of large spatiotemporal extreme events in gross primary production (GPP) as triggers of continental anomalies. We also investigate seasonal dynamics of extreme impacts on continental GPP anomalies. We find that the 50 largest positive (increase in uptake) and negative extremes (decrease in uptake) on each continent can explain most of the continental variation in GPP, which is in line with previous results obtained at the global scale. We show that negative extremes are larger than positive ones and demonstrate that this asymmetry is particularly strong in South America and Europe. Most extremes in GPP start in early summer. Our analysis indicates that the overall impacts and the spatial extents of GPP extremes are power law distributed with exponents that vary little across continents. Moreover, we show that on all continents and for all data sets the spatial extents play a more important role than durations or maximal GPP anomaly when it comes to the overall impact of GPP extremes. An analysis of possible causes implies that across continents most extremes in GPP can best be explained by water scarcity rather than by extreme temperatures. However, for Europe, South America and Oceania we identify also fire as an important driver. Our findings are consistent with remote sensing products. An independent validation against a literature survey on specific extreme events supports our results to a large extent.

  13. Continents on the Move or "Where in the World Did Antarctica Come From?"

    ERIC Educational Resources Information Center

    CSTA Journal, 1995

    1995-01-01

    Presents an activity in which students trace the movement of the continents over the past 600 million years to help them understand how the continents' size and position have changed over time. Includes map puzzle pieces. (MKR)

  14. How Do People Make Continence Care Happen? An Analysis of Organizational Culture in Two Nursing Homes

    ERIC Educational Resources Information Center

    Lyons, Stacie Salsbury

    2010-01-01

    Purpose: Although nursing homes (NHs) are criticized for offering poor quality continence care, little is known about the organizational processes that underlie this care. This study investigated the influence of organizational culture on continence care practices in two NHs. Design and Methods: This ethnographic study explored continence care…

  15. 21 CFR 876.5280 - Implanted mechanical/hydraulic urinary continence device.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Implanted mechanical/hydraulic urinary continence....5280 Implanted mechanical/hydraulic urinary continence device. (a) Identification. An implanted mechanical/hydraulic urinary continence device is a device used to treat urinary incontinence by...

  16. Slow Mid-Lithosphere Beneath the Mid-continent, USA

    NASA Astrophysics Data System (ADS)

    Bedle, H.; van der Lee, S.

    2005-12-01

    The Illinois basin is one of several basins within the North American craton. Despite years of study, the formational mechanisms of the basin remain largely unknown. While the crustal structure of the basin is well-defined from seismic studies, it remains unclear whether the basin is expressed in the sub-crustal structure; and, if the mantle structure provides clues towards an understanding the basin. We study the S-velocity structure of the upper-mantle using seismic tomography beneath the Illinois basin and its surrounding area. Since this area of the North American craton has been relatively stable since 1.4 Gy, significant deviations in S-velocities within the uppermost mantle are not expected. Nevertheless, a slower S-velocity in the upper-mantle of the Illinois basin was previously modeled in the 3D model NA04 (van der Lee and Frederiksen, 2005). To improve resolution and verify the existence of this seismically slow region, we fit seismic waveforms from 11 mid-continent events, using the methodology of Partitioned Waveform Inversion (Nolet, 1990). In doing so, we also incorporate constraints that are representative of the Illinois basin's crustal and sedimentary layering. The resultant 3D model, IL05, confirms the existence of a slow S-velocity structure in the uppermost mantle beneath this region. This anomalously slow region exists from the base of the crust to depths of ~100 km, and is slower than a cratonic average by about 200 m/s. The slow uppermost-mantle beneath the Illinois basin is then underlain by a faster lithosphere typical of the North American craton to depths of ~200 km. The coherency of this deeper cratonic lithosphere rules out a lithospheric delamination origin of the anomaly. The model IL05 points to a heterogeneous mantle beneath the mid-continent. Our imaging agrees with evidence of a heterogeneous mantle recently found in the form of sub-Moho reflectors from reprocessed seismic reflection surveys (McBride and Okure, 2004). The

  17. Currents in the mantle and the geology of continents

    NASA Astrophysics Data System (ADS)

    Wilson, J. Tuzo

    1991-02-01

    This paper is the first of a series which have considered the possible effects of currents in the mantle upon continents. It mentions effects of aging in oceans upon the direction of slope of coastal peneplains. When oceans are young the coasts are cliffs from which peneplains dip downward on the inland side. As the margins separate from the ridge they cool and the slopes reverse. It suggests how Jeffreys' arguments against convection currents breaking the lithosphere can be avoided and discusses the possibility that upwelling has penetrated beneath the southwestern United States.

  18. Exploring the dark continent with fibre Bragg gratings

    NASA Astrophysics Data System (ADS)

    Arkwright, John W.; Wang, David Hsiao-Chuan; Maunder, Simon A.; Blenman, Neil G.; Underhill, Ian; Patton, Vicki; Dinning, Phil G.

    2014-05-01

    The lower gastrointestinal tract has been referred to as the `Dark Continent' of the human body because it is so hard to access without resorting to a surgeon's blade. In response to an unmet clinical need we have developed a fibre optic manometry catheter that is now in clinical use across Australia and New Zealand. The unparalleled detail of colonic activity that these devices provide is being hailed as ground breaking by global experts. In this paper we present the design and clinical application of the catheters, and also some of the (sometimes surprising) requirements of our clinical colleagues.

  19. Pressure injury prevention: continence, skin hygiene and nutrition management.

    PubMed

    Roosen, Kerri; Fulbrook, Paul; Nowicki, Tracy

    2010-08-10

    To prevent pressure injuries research indicates the importance of focusing on three key areas of practice: continence, skin hygiene and nutrition. These are a synergistic trio and many patients require considered management in all three areas. In addition to targeting specific aspects of nursing care in these areas, it is also crucial that there is organisational buy-in for strategic initiatives. Some of the ways that we achieved this are outlined below: Support from managerial level by presenting evidence and education to senior nurses and directors. Nurse unit managers completed individual ward action plans outlining their individual commitments to reducing pressure injuries. Providing support and education to staff to choose and use continence products effectively. Support from allied health colleagues in prevention of pressure injuries. After implementing the actions described above, pressure injury prevalence at the Prince Charles Hospital in Brisbane decreased from 13.78% in 2008 to 5.15% in 2010, representing a 62% reduction overall. Of these pressure injuries, 53% were stage one. PMID:20862898

  20. Permo-carboniferous hydrocarbon accumulations, Mid-continent, USA

    SciTech Connect

    Rascoe, B.; Adler, F.J.

    1983-06-01

    Approximately 19.4 billion bbl of oil and 119 tcf of nonassociated gas have been discovered in the Mid-Continent as of January 1, 1978. Although these volumes of hydrocarbons were trapped in thousands of fields throughout the Mid-Continent, the bulk of these resources were emplaced in a relatively few fields about 14.2 billion bbl of oil have been found in 111 significant and giant oil fields, and 103 tcf of nonassociated gas have been discovered in 57 significant and giant gas fields. PermoCarboniferous reservoirs are important in 101 of the large oil fields and 55 of the large gas fields; these fields contained 9.5 billion bbl of oil and 99 tcf of gas, respectively. Our calculations of the total oil and gas accumulations in Permo-Carboniferous reservoirs extrapolated from these data. About 2.1 billion bbl of oil and 5.1 tcf of nonassociated gas accumulated in Lower Carboniferous (Mississippian) reservoirs. Most of this oil and gas was stratigraphically trapped in Upper Mississippian sandstones and carbonates which are truncated at the pre-Pennsylvanian unconformity surface.

  1. Petroleum geology and hydrocarbon exploration in the continent of China

    SciTech Connect

    Xiaoguang Tong )

    1996-01-01

    The geological structure of the continent of China, which is formed by the amalgamation of three small-sized paleocratons and their peripheral orogenic belts, is very complex. Six big sedimentary basins developed on it: four of them are composite basins on the paleocratons; the other two basins are superimposed on the orogenic belts. In addition, there are a large number of small to middle-sized non-marine sedimentary basins. Up to now, the proved geological reserves in the continent of China are: oil, above 16 billion tons; natural gas, 1000 billion cubic meters. Last year, the annual oil output was more than 140 million tons; natural gas output reached 16 billion cubic meters. The six big basins are still the major exploration potential area. On the other hand, a lot of small to middle-sized reservoirs will be discovered in the small to middle-sized non-marine basins and coal-bearing basins in North China. Qiang Tang Basin and coalbed gas are two favorable frontiers.

  2. Petroleum geology and hydrocarbon exploration in the continent of China

    SciTech Connect

    Xiaoguang Tong

    1996-12-31

    The geological structure of the continent of China, which is formed by the amalgamation of three small-sized paleocratons and their peripheral orogenic belts, is very complex. Six big sedimentary basins developed on it: four of them are composite basins on the paleocratons; the other two basins are superimposed on the orogenic belts. In addition, there are a large number of small to middle-sized non-marine sedimentary basins. Up to now, the proved geological reserves in the continent of China are: oil, above 16 billion tons; natural gas, 1000 billion cubic meters. Last year, the annual oil output was more than 140 million tons; natural gas output reached 16 billion cubic meters. The six big basins are still the major exploration potential area. On the other hand, a lot of small to middle-sized reservoirs will be discovered in the small to middle-sized non-marine basins and coal-bearing basins in North China. Qiang Tang Basin and coalbed gas are two favorable frontiers.

  3. Treatment of continence in people with learning disabilities: 3.

    PubMed

    Stanley, R

    Behaviourism is a model of intervention for people with a learning disability which focuses on observable behaviour and methods of changing it. The behaviourist strategies do not typically place high value on some of the diagnostic labels that have been considered in the first two articles of this series (Vol 5(6): 364-8; Vol 5(8): 492-8). Rather, the behaviourist is concerned with the behaviours a particular individual shows. Behaviour modification is a particular methodology within psychotherapy that has many interpretations, ranging from a rigid orthodoxy through to an eclectic ecumenicism of theoretical models. The third article in this series on the management of continence in people with a learning disability examines the behavioural strategies that have been historically and are currently available to practitioners. The legacy of behaviour modification (1970s style) means that staff do sometimes perceive such strategies as treatment, whereas in fact the treatment is a combination of designing the environment, designing individual programmes and designing specific ways of developing more valuing forms of continence management. PMID:9015995

  4. Robotic Intracorporeal Continent Cutaneous Urinary Diversion: Primary Description.

    PubMed

    Goh, Alvin C; Aghazadeh, Monty A; Krasnow, Ross E; Pastuszak, Alexander W; Stewart, Julie N; Miles, Brian J

    2015-11-01

    The purpose is to present the first report and describe our novel technique for intracorporeal continent cutaneous diversion after robotic cystectomy. After completion of robot-assisted cystectomy using a standard six-port transperitoneal technique, three additional ports are placed, and the robot is redocked laterally over the patient's right side in the modified lateral position. Our technique replicates step-by-step the principles of the open approach. Ileocolonic anastomosis, ureteroenteral anastomoses, and construction of a hand-sewn right colonic pouch are all performed intracorporeally. Tapering of efferent ileal limb and reinforcement of the ileocecal valve are performed via the extraction site, while the stoma is matured through a prospective port site. Successful robotic intracorporeal creation of a modified Indiana pouch was achieved. Operative time for diversion was 3 hours, with negligible blood loss, and without any intraoperative complications. No major (Clavien III-V) 90-day complications were observed. At a follow-up of 1 year, the patient continues to catheterize without difficulty. We demonstrate the first description of robotic intracorporeal continent cutaneous urinary diversion after robot-assisted cystectomy. We present a systematic minimally invasive approach, replicating the principles of open surgery, which is technically feasible and safe with a good functional result. PMID:25556514

  5. Climate control of terrestrial carbon exchange across biomes and continents

    SciTech Connect

    Ricciuto, Daniel M; Gu, Lianhong

    2010-07-01

    Understanding the relationships between climate and carbon exchange by terrestrial ecosystems is critical to predict future levels of atmospheric carbon dioxide because of the potential accelerating effects of positive climate carbon cycle feedbacks. However, directly observed relationships between climate and terrestrial CO2 exchange with the atmosphere across biomes and continents are lacking. Here we present data describing the relationships between net ecosystem exchange of carbon (NEE) and climate factors as measured using the eddy covariance method at 125 unique sites in various ecosystems over six continents with a total of 559 site-years. We find that NEE observed at eddy covariance sites is (1) a strong function of mean annual temperature at mid- and high-latitudes, (2) a strong function of dryness at mid- and low-latitudes, and (3) a function of both temperature and dryness around the mid-latitudinal belt (45 N). The sensitivity of NEE to mean annual temperature breaks down at ~ 16 C (a threshold value of mean annual temperature), above which no further increase of CO2 uptake with temperature was observed and dryness influence overrules temperature influence.

  6. Continents as lithological icebergs: The importance of buoyant lithospheric roots

    USGS Publications Warehouse

    Abbott, D.H.; Drury, R.; Mooney, W.D.

    1997-01-01

    An understanding of the formation of new continental crust provides an important guide to locating the oldest terrestrial rocks and minerals. We evaluated the crustal thicknesses of the thinnest stable continental crust and of an unsubductable oceanic plateau and used the resulting data to estimate the amount of mantle melting which produces permanent continental crust. The lithospheric mantle is sufficiently depleted to produce permanent buoyancy (i.e., the crust is unsubductable) at crustal thicknesses greater than 25-27 km. These unsubductable oceanic plateaus and hotspot island chains are important sources of new continental crust. The newest continental crust (e.g., the Ontong Java plateau) has a basaltic composition, not a granitic one. The observed structure and geochemistry of continents are the result of convergent margin magmatism and metamorphism which modify the nascent basaltic crust into a lowermost basaltic layer overlain by a more silicic upper crust. The definition of a continent should imply only that the lithosphere is unsubductable over ??? 0.25 Ga time periods. Therefore, the search for the oldest crustal rocks should include rocks from lower to mid-crustal levels.

  7. Archean komatiite volcanism controlled by the evolution of early continents.

    PubMed

    Mole, David R; Fiorentini, Marco L; Thebaud, Nicolas; Cassidy, Kevin F; McCuaig, T Campbell; Kirkland, Christopher L; Romano, Sandra S; Doublier, Michael P; Belousova, Elena A; Barnes, Stephen J; Miller, John

    2014-07-15

    The generation and evolution of Earth's continental crust has played a fundamental role in the development of the planet. Its formation modified the composition of the mantle, contributed to the establishment of the atmosphere, and led to the creation of ecological niches important for early life. Here we show that in the Archean, the formation and stabilization of continents also controlled the location, geochemistry, and volcanology of the hottest preserved lavas on Earth: komatiites. These magmas typically represent 50-30% partial melting of the mantle and subsequently record important information on the thermal and chemical evolution of the Archean-Proterozoic Earth. As a result, it is vital to constrain and understand the processes that govern their localization and emplacement. Here, we combined Lu-Hf isotopes and U-Pb geochronology to map the four-dimensional evolution of the Yilgarn Craton, Western Australia, and reveal the progressive development of an Archean microcontinent. Our results show that in the early Earth, relatively small crustal blocks, analogous to modern microplates, progressively amalgamated to form larger continental masses, and eventually the first cratons. This cratonization process drove the hottest and most voluminous komatiite eruptions to the edge of established continental blocks. The dynamic evolution of the early continents thus directly influenced the addition of deep mantle material to the Archean crust, oceans, and atmosphere, while also providing a fundamental control on the distribution of major magmatic ore deposits. PMID:24958873

  8. Archean komatiite volcanism controlled by the evolution of early continents

    PubMed Central

    Mole, David R.; Fiorentini, Marco L.; Thebaud, Nicolas; Cassidy, Kevin F.; McCuaig, T. Campbell; Kirkland, Christopher L.; Romano, Sandra S.; Doublier, Michael P.; Belousova, Elena A.; Barnes, Stephen J.; Miller, John

    2014-01-01

    The generation and evolution of Earth’s continental crust has played a fundamental role in the development of the planet. Its formation modified the composition of the mantle, contributed to the establishment of the atmosphere, and led to the creation of ecological niches important for early life. Here we show that in the Archean, the formation and stabilization of continents also controlled the location, geochemistry, and volcanology of the hottest preserved lavas on Earth: komatiites. These magmas typically represent 50–30% partial melting of the mantle and subsequently record important information on the thermal and chemical evolution of the Archean–Proterozoic Earth. As a result, it is vital to constrain and understand the processes that govern their localization and emplacement. Here, we combined Lu-Hf isotopes and U-Pb geochronology to map the four-dimensional evolution of the Yilgarn Craton, Western Australia, and reveal the progressive development of an Archean microcontinent. Our results show that in the early Earth, relatively small crustal blocks, analogous to modern microplates, progressively amalgamated to form larger continental masses, and eventually the first cratons. This cratonization process drove the hottest and most voluminous komatiite eruptions to the edge of established continental blocks. The dynamic evolution of the early continents thus directly influenced the addition of deep mantle material to the Archean crust, oceans, and atmosphere, while also providing a fundamental control on the distribution of major magmatic ore deposits. PMID:24958873

  9. Correlation of Mid-Continent Virgilian (Late Pennsylvanian) Brachiopods

    SciTech Connect

    Weibel, C.P.

    1986-05-01

    Biostratigraphic correlations of Pennsylvanian strata in the Illinois basin with those of the Western Interior basin have been restricted largely to comparison of ostracode faunules and a few fusulinid occurrences. Seventeen brachiopod species from the Bogota and Greenup Limestone Members of the upper Mattoon Formation in east-central Illinois resemble species from Late Pennsylvanian Mid-Continent localities. Five Bogota species have relatively restricted ranges and are useful for correlation. Neochonetes granulifer var. transversalis is rare in the Douglas Group but abundant in the Shawnee and Wabaunsee. Lissochonetes geinitzianus var. plattsmouthensis ranges from uppermost Missourian to upper Shawnee and L. geinitzianus var. geronticus ranges from upper Wabaunsee to Lower Permian. Derbyia texana occurs in the Thrifty Formation of north Texas (probably upper Shawnee or lower Wabaunsee). Antiquatonia jemezensis has not been reported in the Mid-Continent but occurs in the upper Madera formation (probable Shawnee or early Wabaunsee) of New Mexico. A compositid from the younger Greenup Limestone Member is morphologically intermediate between the Early Pennsylvanian Composita wasatchensis and the middle Permian C. affinis. Other species from the Bogota and Greenup members range throughout the Upper Pennsylvanian, except for one linoproductid of Missourian affinities. This study, along with a previous study of brachiopods (Shumway Limestone Member) and of fusulinids, indicates that the Bogota is of middle Shawnee age, the Greenup is of upper Shawnee or lower Wabaunsee age, and the Missourian-Virgilian boundary in the Illinois basin is stratigraphically near the Omega Limestone Member.

  10. Brain-derived neurotrophic factor in urinary continence and incontinence.

    PubMed

    Song, Qi-Xiang; Chermansky, Christopher J; Birder, Lori A; Li, Longkun; Damaser, Margot S

    2014-10-01

    Urinary incontinence adversely affects quality of life and results in an increased financial burden for the elderly. Accumulating evidence suggests a connection between neurotrophins, such as brain-derived neurotrophic factor (BDNF), and lower urinary tract function, particularly with regard to normal physiological function and the pathophysiological mechanisms of stress urinary incontinence (SUI) and bladder pain syndrome/interstitial cystitis (BPS/IC). The interaction between BDNF and glutamate receptors affects both bladder and external urethral sphincter function during micturition. Clinical findings indicate reduced BDNF levels in antepartum and postpartum women, potentially correlating with postpartum SUI. Experiments with animal models demonstrate that BDNF is decreased after simulated childbirth injury, thereby impeding the recovery of injured nerves and the restoration of continence. Treatment with exogenous BDNF facilitates neural recovery and the restoration of continence. Serotonin and noradrenaline reuptake inhibitors, used to treat both depression and SUI, result in enhanced BDNF levels. Understanding the neurophysiological roles of BDNF in maintaining normal urinary function and in the pathogenesis of SUI and BPS/IC could lead to future therapies based on these mechanisms. PMID:25224451

  11. Hydration of the lithospheric mantle by the descending plate in a continent-continent collisional setting and its geodynamic consequences

    NASA Astrophysics Data System (ADS)

    Massonne, Hans-Joachim

    2016-05-01

    At the beginning of continent-continent collision the descending plate dehydrates. The influence of this dehydration on the adjacent lithospheric mantle was studied. For this reason, pressure (P), temperature (T) and T-H2O pseudosections were calculated for an average mantle composition using the computer software PERPLE_X. These pseudosections were contoured by isopleths, for instance, for volumes of amphibole, chlorite, and serpentine. In addition, P-T pseudosections were considered for four psammopelitic rocks, common in the upper portion of the continental crust, in order to quantify the release of H2O in these rocks during prograde metamorphism. At pressures around 1 GPa, a maximum of slightly more than 10 vol.% chlorite, almost 20 vol.% amphibole, and some talc but no serpentine forms when only 1.8 wt.% H2O is added to the dry ultrabasite at temperatures of 600 °C. For example, hydrous phases amount to about 35 vol.% serpentine and 10 vol.% each of chlorite and amphibole at 1 GPa, 550 °C, and 5 wt.% H2O. The modelled psammopelitic rocks can release 0.8-2.5 wt.% H2O between 450 and 650 °C at 0.8-1.4 GPa. On the basis of the above calculations, different collisional scenarios are discussed highlighting the role of hydrated lithospheric mantle. In this context a minimum hydration potential of the front region of the descending continental plate is considered, which amounts to 4.6 × 1016 kg releasable H2O for a 1000 km wide collisional zone, due to a thick sedimentary pile at the continental margin. Further suggestions are that (1) the lower crustal plate in a continent-continent collisional setting penetrates the lithospheric mantle, which is hydrated during the advancement of this plate, (2) the maximum depths of the subduction of upper continental crust is below 70 km and (3) hydrated mantle above the descending crustal plate is thrust onto this continental crust.

  12. The place of science in a continent at the crossroads.

    PubMed

    Koech, D K

    2001-01-01

    I have mentioned it before and I want to repeat it now, that we in Africa share a common history, heritage and basic problems of development. We, therefore, have an inescapable responsibility of pooling our talents and resources in shaping our common destiny. In fulfillment of its mission, AFHES, through its organized con notgresses and this Journal, is an invaluable vessel for enabling us to promote better health for the peoples of this continent. Africa is a continent endowed with great potential that, for one reason or an notother, has been ignored or misused, resulting in the current crisis now enveloping the continent. There is the escalating debt burden, falling agricultural productivity and the ever-increasing population. Efforts to improve the situation are hampered by adverse factors such as malnutrition, HTV/AIDS, malaria and other causes of ill health; wars, poor environmental management and the ever-worrisome problem of refugees. At the sunrise of the 21st Century, we must wake up and reverse the current trend by focusing our resources on priority areas of development. The fight for freedom from the yoke of colonialism and the traumatic experience of apartheid has been won. In some African countries, however, the winning of the fight for freedom has opened up a new fight, a fight that is more fierce and bloody than that which set us free. These include civil strife and internecine wars giving rise to a new black Diaspora, which is far greater than the one experienced during the period of slavery and slave trade. People supposed to build these nations have either been killed or forced into exile. Those intellectually endowed have sought refuge in safer and economically developed countries and, by the same process, also weaken the al notready weak economies of their mother countries. They have, therefore, helped to strengthen the already strong economies of the developed nations. This is indeed, a sad situation that poses a formidable challenge to the

  13. OxyContin® as currency: OxyContin® use and increased social capital among rural Appalachian drug users.

    PubMed

    Jonas, Adam B; Young, April M; Oser, Carrie B; Leukefeld, Carl G; Havens, Jennifer R

    2012-05-01

    Studies have shown that position within networks of social relations can have direct implications on the health behaviors of individuals. The present study examines connections between drug use and individual social capital within social networks of drug users (n = 503) from rural Appalachian Kentucky, U.S.A. Respondent driven sampling was used to recruit individuals age 18 and older who had used one of the following drugs to get high: cocaine, crack, heroin, methamphetamine, or prescription opioids. Substance use was measured via self-report and social network analysis of participants' drug use network was used to compute effective size, a measure of social capital. Drug network ties were based on sociometric data on recent (past 6 month) drug co-usage. Multivariate multi-level ordinal regression was used to model the independent effect of socio-demographic and drug use characteristics on social capital. Adjusting for gender, income, and education, daily OxyContin(®) use was found to be significantly associated with greater social capital, and daily marijuana use was associated with less social capital. These results suggest that in regions with marked economic disparities such as rural Appalachia, OxyContin(®) may serve as a form of currency that is associated with increased social capital among drug users. Interventions focusing on increasing alternate pathways to acquiring social capital may be one way in which to alleviate the burden of drug use in this high-risk population. PMID:22465379

  14. OxyContin® as Currency: OxyContin® Use and Increased Social Capital among Rural Appalachian Drug Users

    PubMed Central

    Jonas, Adam B.; Young, April M.; Oser, Carrie B.; Leukefeld, Carl G.; Havens, Jennifer R.

    2012-01-01

    Studies have shown that position within networks of social relations can have direct implications on the health behaviors of individuals. The present study examines connections between drug use and individual social capital within social networks of drug users (n=503) from rural Appalachian Kentucky, U.S.A. Respondent driven sampling was used to recruit individuals age 18 and older who had used one of the following drugs to get high: cocaine, crack, heroin, methamphetamine, or prescription opioids. Substance use was measured via self-report and social network analysis of participants’ drug use network was used to compute effective size, a measure of social capital. Drug network ties were based on sociometric data on recent (past 6 month) drug co-usage. Multivariate multi-level ordinal regression was used to model the independent effect of sociodemographic and drug use characteristics on social capital. Adjusting for gender, income, and education, daily OxyContin® use was found to be significantly associated with greater social capital, and daily marijuana use was associated with less social capital. These results suggest that in regions with marked economic disparities such as rural Appalachia, OxyContin® may serve as a form of currency that is associated with increased social capital among drug users. Interventions focusing on increasing alternate pathways to acquiring social capital may be one way in which to alleviate the burden of drug use in this high-risk population. PMID:22465379

  15. Simulation of active tectonic processes for a convecting mantle with moving continents

    USGS Publications Warehouse

    Trubitsyn, V.; Kaban, M.; Mooney, W.; Reigber, C.; Schwintzer, P.

    2006-01-01

    Numerical models are presented that simulate several active tectonic processes. These models include a continent that is thermally and mechanically coupled with viscous mantle flow. The assumption of rigid continents allows use of solid body equations to describe the continents' motion and to calculate their velocities. The starting point is a quasi-steady state model of mantle convection with temperature/ pressure-dependent viscosity. After placing a continent on top of the mantle, the convection pattern changes. The mantle flow subsequently passes through several stages, eventually resembling the mantle structure under present-day continents: (a) Extension tectonics and marginal basins form on boundary of a continent approaching to subduction zone, roll back of subduction takes place in front of moving continent; (b) The continent reaches the subduction zone, the extension regime at the continental edge is replaced by strong compression. The roll back of the subduction zone still continues after closure of the marginal basin and the continent moves towards the upwelling. As a result the ocean becomes non-symmetric and (c) The continent overrides the upwelling and subduction in its classical form stops. The third stage appears only in the upper mantle model with localized upwellings. ?? 2006 The Authors Journal compilation ?? 2006 RAS.

  16. A Zn isotope perspective on the rise of continents.

    PubMed

    Pons, M-L; Fujii, T; Rosing, M; Quitté, G; Télouk, P; Albarède, F

    2013-05-01

    Zinc isotope abundances are fairly constant in igneous rocks and shales and are left unfractionated by hydrothermal processes at pH < 5.5. For that reason, Zn isotopes in sediments can be used to trace the changing chemistry of the hydrosphere. Here, we report Zn isotope compositions in Fe oxides from banded iron formations (BIFs) and iron formations of different ages. Zinc from early Archean samples is isotopically indistinguishable from the igneous average (δ(66) Zn ~0.3‰). At 2.9-2.7 Ga, δ(66) Zn becomes isotopically light (δ(66) Zn < 0‰) and then bounces back to values >1‰ during the ~2.35 Ga Great Oxygenation Event. By 1.8 Ga, BIF δ(66) Zn has settled to the modern value of FeMn nodules and encrustations (~0.9‰). The Zn cycle is largely controlled by two different mechanisms: Zn makes strong complexes with phosphates, and phosphates in turn are strongly adsorbed by Fe hydroxides. We therefore review the evidence that the surface geochemical cycles of Zn and P are closely related. The Zn isotope record echoes Sr isotope evidence, suggesting that erosion starts with the very large continental masses appearing at ~2.7 Ga. The lack of Zn fractionation in pre-2.9 Ga BIFs is argued to reflect the paucity of permanent subaerial continental exposure and consequently the insignificant phosphate input to the oceans and the small output of biochemical sediments. We link the early decline of δ(66) Zn between 3.0 and 2.7 Ga with the low solubility of phosphate in alkaline groundwater. The development of photosynthetic activity at the surface of the newly exposed continents increased the oxygen level in the atmosphere, which in turn triggered acid drainage and stepped up P dissolution and liberation of heavy Zn into the runoff. Zinc isotopes provide a new perspective on the rise of continents, the volume of carbonates on continents, changing weathering conditions, and compositions of the ocean through time. PMID:23421593

  17. Comparison of different evaporation estimates over the African continent

    NASA Astrophysics Data System (ADS)

    Trambauer, P.; Dutra, E.; Maskey, S.; Werner, M.; Pappenberger, F.; van Beek, L. P. H.; Uhlenbrook, S.

    2014-01-01

    Evaporation is a key process in the water cycle with implications ranging, inter alia, from water management to weather forecast and climate change assessments. The estimation of continental evaporation fluxes is complex and typically relies on continental-scale hydrological models or land-surface models. However, it appears that most global or continental-scale hydrological models underestimate evaporative fluxes in some regions of Africa, and as a result overestimate stream flow. Other studies suggest that land-surface models may overestimate evaporative fluxes. In this study, we computed actual evaporation for the African continent using a continental version of the global hydrological model PCR-GLOBWB, which is based on a water balance approach. Results are compared with other independently computed evaporation products: the evaporation results from the ECMWF reanalysis ERA-Interim and ERA-Land (both based on the energy balance approach), the MOD16 evaporation product, and the GLEAM product. Three other alternative versions of the PCR-GLOBWB hydrological model were also considered. This resulted in eight products of actual evaporation, which were compared in distinct regions of the African continent spanning different climatic regimes. Annual totals, spatial patterns and seasonality were studied and compared through visual inspection and statistical methods. The comparison shows that the representation of irrigation areas has an insignificant contribution to the actual evaporation at a continental scale with a 0.5° spatial resolution when averaged over the defined regions. The choice of meteorological forcing data has a larger effect on the evaporation results, especially in the case of the precipitation input as different precipitation input resulted in significantly different evaporation in some of the studied regions. ERA-Interim evaporation is generally the highest of the selected products followed by ERA-Land evaporation. In some regions, the satellite

  18. Comparison of different evaporation estimates over the African continent

    NASA Astrophysics Data System (ADS)

    Trambauer, P.; Dutra, E.; Maskey, S.; Werner, M.; Pappenberger, F.; van Beek, L. P. H.; Uhlenbrook, S.

    2013-07-01

    Evaporation is a key process in the water cycle, with implications ranging from water management, to weather forecast and climate change assessments. The estimation of continental evaporation fluxes is complex and typically relies on continental-scale hydrological or land-surface models. However, it appears that most global or continental-scale hydrological models underestimate evaporative fluxes in some regions of Africa, and as a result overestimate stream flow. Other studies suggest that land-surface models may overestimate evaporative fluxes. In this study, we computed actual evaporation for the African continent using a continental version of the global hydrological model PCR-GLOBWB, which is based on a water balance approach. Results are compared with other independently computed evaporation products: the evaporation results from the ECMWF reanalysis ERA-Interim and ERA-Land (both based on the energy balance approach), the MOD16 evaporation product, and the GLEAM product. Three other alternative versions of the PCR-GLOBWB hydrological model were also considered. This resulted in eight products of actual evaporation, which were compared in distinct regions of the African continent spanning different climatic regimes. Annual totals, spatial patterns and seasonality were studied and compared through visual inspection and statistical methods. The comparison shows that the representation of irrigation areas has an insignificant contribution to the actual evaporation at a continental scale with a 0.5° spatial resolution. The choice of meteorological forcing data has a larger effect on the evaporation results, especially in the case of the precipitation input as different precipitation input resulted in significantly different evaporation in some of the studied regions. ERA-Interim evaporation is generally the highest of the selected products followed by ERA-Land evaporation. The satellite based products (GLEAM and MOD16) do not show regular behaviour when compared

  19. Asynchronous extinction of late Quaternary sloths on continents and islands

    PubMed Central

    Steadman, David W.; Martin, Paul S.; MacPhee, Ross D. E.; Jull, A. J. T.; McDonald, H. Gregory; Woods, Charles A.; Iturralde-Vinent, Manuel; Hodgins, Gregory W. L.

    2005-01-01

    Whatever the cause, it is extraordinary that dozens of genera of large mammals became extinct during the late Quaternary throughout the Western Hemisphere, including 90% of the genera of the xenarthran suborder Phyllophaga (sloths). Radiocarbon dates directly on dung, bones, or other tissue of extinct sloths place their “last appearance” datum at ≈11,000 radiocarbon years before present (yr BP) or slightly less in North America, ≈10,500 yr BP in South America, and ≈4,400 yr BP on West Indian islands. This asynchronous situation is not compatible with glacial–interglacial climate change forcing these extinctions, especially given the great elevational, latitudinal, and longitudinal variation of the sloth-bearing continental sites. Instead, the chronology of last appearance of extinct sloths, whether on continents or islands, more closely tracks the first arrival of people. PMID:16085711

  20. [Chiroptera and zoonosis: an emerging problem on all five continents].

    PubMed

    Hance, P; Garnotel, E; Morillon, M

    2006-04-01

    Zoonosis is the cause of the vast majority of emerging diseases. Bats that occupy the second place in the mammal class play an important role. Whether they belong to the microchiroptera suborder or to the megachiroptera suborder, bats on all five continents have been implicated in transmission of numerous pathogens including not only viruses such as Lyssavirus (e.g. rabies), Hepanivirus (e.g. Hendra and Nipah virus) and recently coronavirus (e.g. SARS-like coronavirus and Ebola virus) but also fungus such as histoplasmosis. By modifying environmental conditions and encroaching on their biotope, human intervention has probably contributed to the introduction of chiropteras into an epidemiologic chain in which they previously had no place, thus promoting the emergence of new pathogens. PMID:16775933

  1. The evolving continents /2nd revised and enlarged edition/

    NASA Astrophysics Data System (ADS)

    Windley, B. F.

    The earth's history is traced through the tectonic evolution of the continental crust from the very beginning of the geological record, rather than by studying the stratigraphy of a particular area. The topics addressed include: Archean granulite-gneiss belts; Archean greenstone belts; crustal evolution in the Archean; early to mid-Proterozoic basic ultrabasic intrusion, basins, and belts; mid-Proterozoic anorogenic magmatism and abortive rifting; mid-late Proterozoic basins, dykes, glaciations, and life forms; late Proterozoic mobile belts; and crustal evolution in the Proterozoic. Also considered are: paleomagnetism and continental drift; paleoclimatology and the fossil record; Caledonian-Appalachian fold belt; the Hercynian fold belt; Pangaea and its breakup; plate tectonics and sea-floor spreading; island arcs; continental margin orogenic belts; the Western Americas; the Alpine fold belt; the Himalayas; and the evolving continents.

  2. Plasmodium vivax Diversity and Population Structure across Four Continents.

    PubMed

    Koepfli, Cristian; Rodrigues, Priscila T; Antao, Tiago; Orjuela-Sánchez, Pamela; Van den Eede, Peter; Gamboa, Dionicia; van Hong, Nguyen; Bendezu, Jorge; Erhart, Annette; Barnadas, Céline; Ratsimbasoa, Arsène; Menard, Didier; Severini, Carlo; Menegon, Michela; Nour, Bakri Y M; Karunaweera, Nadira; Mueller, Ivo; Ferreira, Marcelo U; Felger, Ingrid

    2015-01-01

    Plasmodium vivax is the geographically most widespread human malaria parasite. To analyze patterns of microsatellite diversity and population structure across countries of different transmission intensity, genotyping data from 11 microsatellite markers was either generated or compiled from 841 isolates from four continents collected in 1999-2008. Diversity was highest in South-East Asia (mean allelic richness 10.0-12.8), intermediate in the South Pacific (8.1-9.9) Madagascar and Sudan (7.9-8.4), and lowest in South America and Central Asia (5.5-7.2). A reduced panel of only 3 markers was sufficient to identify approx. 90% of all haplotypes in South Pacific, African and SE-Asian populations, but only 60-80% in Latin American populations, suggesting that typing of 2-6 markers, depending on the level of endemicity, is sufficient for epidemiological studies. Clustering analysis showed distinct clusters in Peru and Brazil, but little sub-structuring was observed within Africa, SE-Asia or the South Pacific. Isolates from Uzbekistan were exceptional, as a near-clonal parasite population was observed that was clearly separated from all other populations (FST>0.2). Outside Central Asia FST values were highest (0.11-0.16) between South American and all other populations, and lowest (0.04-0.07) between populations from South-East Asia and the South Pacific. These comparisons between P. vivax populations from four continents indicated that not only transmission intensity, but also geographical isolation affect diversity and population structure. However, the high effective population size results in slow changes of these parameters. This persistency must be taken into account when assessing the impact of control programs on the genetic structure of parasite populations. PMID:26125189

  3. Laparoscopic Mitrofanoff continent catheterisable stoma in children with spina bifida

    PubMed Central

    Reddy, Mallikarjun N.; Nerli, Rajendra B.; Patil, Ranjeet A.; Jali, Sujata M.

    2015-01-01

    Background: In 1980, Mitrofanoff described the creation of an appendicovesicostomy for continent urinary diversion. This procedure greatly facilitates clean intermittent catheterisation in patients with neurogenic bladder. The purpose of our study was to determine the clinical efficacy of the laparoscopic Mitrofanoff catheterisable stoma for children and adolescents with spina bifida. Materials and Methods: Review of hospital records revealed that 11 children with spina bifida underwent a laparoscopic Mitrofanoff procedure with at least 1-year of follow-up. A four-port transperitoneal laparoscopic approach was used to create a Mitrofanoff appendicovesicostomy. The child was followed-up in the urology clinic at 6 weeks, 3 months, 6 months, 1-year, and then semiannually after that. Questionnaires were administered to determine, from the children's perspective, the level of satisfaction with catheterisation and the psychosocial implications of catheterisation before and after the creation of the Mitrofanoff continent catheterisable stoma. Results: Of the 11 children, six were female, and five were male. The mean age at presentation to Paediatric urological services was 11 ± 3.22 years. Overall the mean operative time was 144.09 ± 17.00 min. Mean estimated blood loss was 37.36 ± 11.44 cc. None of the cases needed conversion to open. Patient satisfaction with their catheterisation was measured at 2.18 ± 0.98 preoperatively, Post-operatively, this improved to 4.27 ± 0.46. Statistical analysis using paired t-test showed significance with P < 001. Conclusions: Laparoscopic Mitrofanoff catheterisable stoma is feasible in children with spina bifida and is associated with reasonable outcome with early recovery, resumption of normal activities and excellent cosmesis. PMID:26168751

  4. Plasmodium vivax Diversity and Population Structure across Four Continents

    PubMed Central

    Koepfli, Cristian; Rodrigues, Priscila T.; Antao, Tiago; Orjuela-Sánchez, Pamela; Van den Eede, Peter; Gamboa, Dionicia; van Hong, Nguyen; Bendezu, Jorge; Erhart, Annette; Barnadas, Céline; Ratsimbasoa, Arsène; Menard, Didier; Severini, Carlo; Menegon, Michela; Nour, Bakri Y. M.; Karunaweera, Nadira; Mueller, Ivo; Ferreira, Marcelo U.; Felger, Ingrid

    2015-01-01

    Plasmodium vivax is the geographically most widespread human malaria parasite. To analyze patterns of microsatellite diversity and population structure across countries of different transmission intensity, genotyping data from 11 microsatellite markers was either generated or compiled from 841 isolates from four continents collected in 1999–2008. Diversity was highest in South-East Asia (mean allelic richness 10.0–12.8), intermediate in the South Pacific (8.1–9.9) Madagascar and Sudan (7.9–8.4), and lowest in South America and Central Asia (5.5–7.2). A reduced panel of only 3 markers was sufficient to identify approx. 90% of all haplotypes in South Pacific, African and SE-Asian populations, but only 60–80% in Latin American populations, suggesting that typing of 2–6 markers, depending on the level of endemicity, is sufficient for epidemiological studies. Clustering analysis showed distinct clusters in Peru and Brazil, but little sub-structuring was observed within Africa, SE-Asia or the South Pacific. Isolates from Uzbekistan were exceptional, as a near-clonal parasite population was observed that was clearly separated from all other populations (FST>0.2). Outside Central Asia FST values were highest (0.11–0.16) between South American and all other populations, and lowest (0.04–0.07) between populations from South-East Asia and the South Pacific. These comparisons between P. vivax populations from four continents indicated that not only transmission intensity, but also geographical isolation affect diversity and population structure. However, the high effective population size results in slow changes of these parameters. This persistency must be taken into account when assessing the impact of control programs on the genetic structure of parasite populations. PMID:26125189

  5. Stagnant loop syndrome in patients with continent ileostomy (intra-abdominal ileal reservoir).

    PubMed Central

    Schjonsby, H; Halvorsen, J F; Hofstad, T; Hovdenak, N

    1977-01-01

    Intestinal absorption and bacteriology of the ileal contents were compared in seven patients with continent ileostomy and seven patients with conventional ileostomy. The absorption of vitamin B12 was reduced in five patients with continent ileostomy and subnormal in two patients with conventional ileostomy. Steatorrhoea was present in four patients with continent and one patient with conventional ileostomy. Increased concentrations of total anaerobic bacteria and Bacteroides were found in the ileum of the patients with continent ileostomy. After an oral dose of (1-14C) glycocholic acid there was no difference in the faecal excretion of radioactivity, whereas the 14CO2-expiration was increased in two patients with continent ileostomy. In four patients with continent ileostomy and malabsorption of B12, there was evidence of a stagnant loopsyndrome as oral lincomycin treatment resulted in increased absorption of B12 decreased excretion of faecal fat, and decreased concentrations of Bacteroides in the ileum. PMID:590837

  6. Recent Aeromagnetic Anomaly views of the Antarctic continent

    NASA Astrophysics Data System (ADS)

    Ferraccioli, F.

    2012-04-01

    Antarctica is a keystone within the Gondwana and Rodinia supercontinents. However, despite intense geological research along the coastal fringes of Antarctica, the interior of the continent remains one of the most poorly understood regions on Earth. Aeromagnetic investigations are a useful tool to help disclose the structure and the evolution of continents from the Precambrian to the Cenozoic and Antarctica is no exception. Here I review a variety of aeromagnetic studies in East and West Antarctica performed since the completion of the first generation ADMAP -Antarctic Digital Magnetic Anomaly Project- in 2001. In western Dronning Maud, in East Antarctica, aeromagnetic data help delineate the extent of the Jurassic Jutulstraumen subglacial rift that is flanked by remnants of a Grenvillian-age (ca 1.1. Ga) igneous province and magmatic arc. Different magnetic signatures appear to characterize the Coats Land block but reconnaissance surveys are insufficient to fully delineate the extent and significance of the Coats Land block, a possible tectonic tracer of Laurentia within Rodinia (Loewy et al., 2011). Further in the interior of East Antarctica, a mosaic of distinct and hitherto largely unknown Precambrian provinces has recently been revealed by combining aeromagnetic and satellite magnetic data with models of crustal thickness constrained by gravity modeling and seismology (Ferraccioli et al., 2011, Nature). A major collisional suture may lie between the Archean Ruker Province and an inferred Proterozoic Gamburtsev Province but the age of final assembly of central East Antarctica remains uncertain and controversial. I favour a Grenville-age collisional event (linked to Rodinia assembly) or possibly older Paleoproteroic collision, followed by intraplate reactivation, as opposed to Neoproterozoic or Early Cambrian collision linked to East-West Gondwana assembly (Boger, 2011). New aerogeophysical surveys over Prince Elizabeth and Queen Mary Land could test this

  7. GOCE observations for Mineral exploration in Africa and across continents

    NASA Astrophysics Data System (ADS)

    Braitenberg, Carla

    2014-05-01

    The gravity anomaly field over the whole Earth obtained by the GOCE satellite is a revolutionary tool to reveal geologic information on a continental scale for the large areas where conventional gravity measurements have yet to be made (e.g. Alvarez et al., 2012). It is, however, necessary to isolate the near-surface geologic signal from the contributions of thickness variations in the crust and lithosphere and the isostatic compensation of surface relief (e.g. Mariani et al., 2013) . Here Africa is studied with particular emphasis on selected geological features which are expected to appear as density inhomogeneities. These include cratons and fold belts in the Precambrian basement, the overlying sedimentary basins and magmatism, as well as the continental margins. Regression analysis between gravity and topography shows coefficients that are consistently positive for the free air gravity anomaly and negative for the Bouguer gravity anomaly (Braitenberg et al., 2013; 2014). The error and scatter on the regression is smallest in oceanic areas, where it is a possible tool for identifying changes in crustal type. The regression analysis allows the large gradient in the Bouguer anomaly signal across continental margins to be removed. After subtracting the predicted effect of known topography from the original Bouguer anomaly field, the residual field shows a continent-wide pattern of anomalies that can be attributed to regional geological structures. A few of these are highlighted, such as those representing Karoo magmatism, the Kibalian foldbelt, the Zimbabwe Craton, the Cameroon and Tibesti volcanic deposits, the Benue Trough and the Luangwa Rift. A reconstruction of the pre-break up position of Africa, South and North America is made for the residual GOCE gravity field obtaining today's gravity field of the plates forming West Gondwana. The reconstruction allows the positive and negative anomalies to be compared across the continental fragments, and so helps

  8. A model of weathering intensity for the Australian continent

    NASA Astrophysics Data System (ADS)

    Wilford, J.

    2013-12-01

    Regolith encompasses all weathered materials in the zone between the Earth's surface and fresh bedrock at depth. This weathered zone includes the soil, which may constitute the whole of the regolith profile or represent only its upper part. Important hydrological and biogeochemical processes operate within the regolith, including the infiltration and storage of near-surface water and nutrients, which sustain agricultural productivity. The degree to which the regolith is weathered (or its weathering intensity) is intrinsically linked to the factors involved in soil formation including parent material, climate, topography, biota and time. The degree to which the bedrock or sediments are weathered has a significant effect on the nature and distribution of regolith materials. There is commonly a strong correlation between weathering intensity and the degree of soil development as well as the depth of the weathering front. Changes in weathering intensity correspond to changes in the geochemical and physical properties of bedrock, ranging from essentially unweathered parent materials through to intensely weathered and leached regolith where all traits of the original protolith (original unweathered rock) are overprinted or lost altogether. With increasing weathering intensity we see mineral and geochemical convergence to more resistant secondary weathered materials including clay, silica, and various oxides. A weathering intensity index (WII) over the Australian continent has been developed at a 100 m resolution using two regression models based on airborne gamma-ray spectrometry imagery and the Shuttle Radar Topography Mission (SRTM) elevation data. Airborne gamma-ray spectrometry measures the concentration of three radioelements -- potassium (K), thorium (Th) and uranium (U) at the Earth's surface. The total gamma-ray flux (dose) is also calculated based on the weighted additions of the three radioelements. In general K is leached with increasing weathering whereas Th

  9. Convective Transport of Trace Gases in the Maritime Continent

    NASA Astrophysics Data System (ADS)

    Harris, Neil

    2015-04-01

    Passage of air through the Tropical Tropopause Layer (TTL) is the major route for troposphere to stratosphere transport. The UK CAST (Co-ordinated Airborne Studies in the Tropics) campaign took place in the West Pacific in January/February 2014. The field campaign was based mainly in Guam (13.5oN, 144.8oE) and had three components: CAST with the NERC FAAM BAe-146 research aircraft; the NASA ATTREX project based around the Global Hawk; the NCAR-led CONTRAST campaign based around the Gulfstream V (HIAPER) aircraft. Together, these aircraft were able to make detailed measurements of atmospheric structure and composition from the ocean surface to 20 km. The CAST team also made ground-based and ozonesonde measurements at the ARM site on Manus Island in Papua New Guinea during February 2014, and halocarbon measurements were made at several West Pacific sites. I will present an overview of the CAST campaign along with the results of high resolution global Unified Model studies and NAME (Numerical Atmospheric-dispersion Modelling Environment) trajectory calculations to look at the transport of air into the TTL in convective systems over the Maritime continent and West Pacific. I will focus on the transport of air from in and around the boundary layer and will assess the possible importance of natural and anthropogenic emissions for TTL composition.

  10. Volcanic passive margins: another way to break up continents.

    PubMed

    Geoffroy, L; Burov, E B; Werner, P

    2015-01-01

    Two major types of passive margins are recognized, i.e. volcanic and non-volcanic, without proposing distinctive mechanisms for their formation. Volcanic passive margins are associated with the extrusion and intrusion of large volumes of magma, predominantly mafic, and represent distinctive features of Larges Igneous Provinces, in which regional fissural volcanism predates localized syn-magmatic break-up of the lithosphere. In contrast with non-volcanic margins, continentward-dipping detachment faults accommodate crustal necking at both conjugate volcanic margins. These faults root on a two-layer deformed ductile crust that appears to be partly of igneous nature. This lower crust is exhumed up to the bottom of the syn-extension extrusives at the outer parts of the margin. Our numerical modelling suggests that strengthening of deep continental crust during early magmatic stages provokes a divergent flow of the ductile lithosphere away from a central continental block, which becomes thinner with time due to the flow-induced mechanical erosion acting at its base. Crustal-scale faults dipping continentward are rooted over this flowing material, thus isolating micro-continents within the future oceanic domain. Pure-shear type deformation affects the bulk lithosphere at VPMs until continental breakup, and the geometry of the margin is closely related to the dynamics of an active and melting mantle. PMID:26442807

  11. Volcanic passive margins: another way to break up continents

    PubMed Central

    Geoffroy, L.; Burov, E. B.; Werner, P.

    2015-01-01

    Two major types of passive margins are recognized, i.e. volcanic and non-volcanic, without proposing distinctive mechanisms for their formation. Volcanic passive margins are associated with the extrusion and intrusion of large volumes of magma, predominantly mafic, and represent distinctive features of Larges Igneous Provinces, in which regional fissural volcanism predates localized syn-magmatic break-up of the lithosphere. In contrast with non-volcanic margins, continentward-dipping detachment faults accommodate crustal necking at both conjugate volcanic margins. These faults root on a two-layer deformed ductile crust that appears to be partly of igneous nature. This lower crust is exhumed up to the bottom of the syn-extension extrusives at the outer parts of the margin. Our numerical modelling suggests that strengthening of deep continental crust during early magmatic stages provokes a divergent flow of the ductile lithosphere away from a central continental block, which becomes thinner with time due to the flow-induced mechanical erosion acting at its base. Crustal-scale faults dipping continentward are rooted over this flowing material, thus isolating micro-continents within the future oceanic domain. Pure-shear type deformation affects the bulk lithosphere at VPMs until continental breakup, and the geometry of the margin is closely related to the dynamics of an active and melting mantle. PMID:26442807

  12. Volcanic passive margins: another way to break up continents

    NASA Astrophysics Data System (ADS)

    Geoffroy, L.; Burov, E. B.; Werner, P.

    2015-10-01

    Two major types of passive margins are recognized, i.e. volcanic and non-volcanic, without proposing distinctive mechanisms for their formation. Volcanic passive margins are associated with the extrusion and intrusion of large volumes of magma, predominantly mafic, and represent distinctive features of Larges Igneous Provinces, in which regional fissural volcanism predates localized syn-magmatic break-up of the lithosphere. In contrast with non-volcanic margins, continentward-dipping detachment faults accommodate crustal necking at both conjugate volcanic margins. These faults root on a two-layer deformed ductile crust that appears to be partly of igneous nature. This lower crust is exhumed up to the bottom of the syn-extension extrusives at the outer parts of the margin. Our numerical modelling suggests that strengthening of deep continental crust during early magmatic stages provokes a divergent flow of the ductile lithosphere away from a central continental block, which becomes thinner with time due to the flow-induced mechanical erosion acting at its base. Crustal-scale faults dipping continentward are rooted over this flowing material, thus isolating micro-continents within the future oceanic domain. Pure-shear type deformation affects the bulk lithosphere at VPMs until continental breakup, and the geometry of the margin is closely related to the dynamics of an active and melting mantle.

  13. Capillary zone electrophoresis of humic acids from the American continent.

    PubMed

    Pacheco, Maria de Lourdes; Havel, Josef

    2002-01-01

    A multicomponent background electrolyte (BGE) was developed and its composition optimized using artificial neural networks (ANN). The optimal BGE composition was found to be 90 mM boric acid, 115 mM Tris, and 0.75 mM EDTA (pH 8.4). A separation voltage of 20 kV, 20 degrees C and detection at 210 nm were used. The method was applied to characterize several humic acids originating from various countries of the American continent: soil (Argentina), peat (Brazil), leonardite (Guatemala and Mexico) and coal (United States). Comparison with humic acids of International Humic Substances Society (IHSS) standard samples was also done. Well reproducible electropherograms showing a relatively high number of peaks were obtained. Characterization of the samples by elemental analysis and UV spectrophotometry was also done. In spite of the very different origins, the similarities between humic acids are high and by matrix assisted desorption/ionization-time of flight (MALDI-TOF)-mass spectrometry it was shown that most of the m/z patterns are the same in all humic acids. This means that humic acids of different origin have the same structural units or that they contain the same components. PMID:11840535

  14. The antegrade continence enema procedure and total anorectal reconstruction

    PubMed Central

    Zbar, Andrew P.

    2014-01-01

    Patients may present with anal incontinence (AI) following repair of a congenital anorectal anomaly years previously, or require total anorectal reconstruction (TAR) following radical rectal extirpation, most commonly for rectal cancer. Others may require removal of their colostomy following sphincter excision for Fournier's gangrene, or in cases of severe perineal trauma. Most of the data pertaining to antegrade continence enema (the ACE or Malone procedure) comes from the pediatric literature in the management of children with AI, but also with supervening chronic constipation, where the quality of life and compliance with this technique appears superior to retrograde colonic washouts. Total anorectal reconstruction requires an anatomical or physical supplement to the performance of a perineal colostomy, which may include an extrinsic muscle interposition (which may or may not be ‘dynamized'), construction of a neorectal reservoir, implantation of an incremental artificial bowel sphincter or creation of a terminal, smooth-muscle neosphincter. The advantages and disadvantages of these techniques and their outcome are presented here. PMID:24759342

  15. The ocean-continent transition of western Iberia

    SciTech Connect

    Whitmarsh, R.B.; Miles, P.R.; Pinheiro, L.M. ); Boillot, G. ); Recq, M. )

    1991-08-01

    The western continental margin of the Iberian peninsular has the characteristic of a rifted non-volcanic continental margin with half-graben and tilted fault blocks seen in several places on multichannel seismic reflection profiles. The ocean-continent transition (OCT) is therefore expected to be where thinned continental crust and oceanic crust are juxtaposed, as elsewhere. The authors located the OCT off western Iberia in order to constrain the pre-lift fit of Iberia to North America. This fit is only marginally constrained by sea-floor spreading magnetic anomalies because the Cretaceous constant polarity interval is adjacent to the OCT. Thinned continental crust can be distinguished from oceanic crust by the nature of the lower crustal velocity structure. In 1986-1987, a series of seismic refraction profiles was shot across three parts of the Iberian Abyssal Plain, the OCT can be detected not only from seismic velocities but also by modeling magnetic anomalies. The chosen location of the OCT is consistent with the interpretation of subsequently acquired multichannel profiles. Off Galicia Bank, the OCT, recognized from seismic velocities and multichannel profiles, corresponds to a seabed peridotite ridge, which has been extensively sampled. In the Tagus Abyssal Plain, limited seismic data gives a less clear picture of the OCT.

  16. 21 CFR 876.5280 - Implanted mechanical/hydraulic urinary continence device.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ....5280 Implanted mechanical/hydraulic urinary continence device. (a) Identification. An implanted mechanical/hydraulic urinary continence device is a device used to treat urinary incontinence by the... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Implanted mechanical/hydraulic urinary...

  17. 21 CFR 876.5280 - Implanted mechanical/hydraulic urinary continence device.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ....5280 Implanted mechanical/hydraulic urinary continence device. (a) Identification. An implanted mechanical/hydraulic urinary continence device is a device used to treat urinary incontinence by the... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Implanted mechanical/hydraulic urinary...

  18. Organic geochemistry of mid-continent Ordovician oils

    SciTech Connect

    Palmer, S.E.

    1985-01-01

    Early Paleozoic oils retain the biochemical imprint of oceanic life prior to evolution of land plants and vertebrates. Thus, these oils have geochemical features which make them unique with respect to younger oils, but also share some common properties with the latter. Characteristic mid-continent Ordovician oil features include predominance of n-C/sub 14/ to n-C/sub 19/ over n-C/sub 20/+ alkanes in the C/sub 15/+ saturate hydrocarbon fraction, low amounts of isoprenoids and abundant C/sub 27/ and C/sub 29/ diasteranes relative to normal steranes. Properties common to both Ordovician and younger oils are: nearly equal amounts of C/sub 15/+ n-alkanes, cycloalkanes, and aromatics and pristane/phytane ratios of 0.7 to 1.6. Collectively, these Ordovician oils have a relatively negative stable carbon isotopic composition but are not unique with respect to other marine oils. Although terpane distributions are generally similar to geologically-younger oils, the Ordovician oils contain significant amounts of C/sub 19/, C/sub 20/, and C/sub 21/ tricyclic diterpanes relative to the C/sub 23/ homolog as well as large contributions by C/sub 31/+ pentacyclic triterpanes. Presence of long-chained n-alkanes, C/sub 29/ steranes, and C/sub 24/ tetracyclic terpanes, which are generally accepted as input from land plants in, e.g., Tertiary deposits, are also present in Ordovician oils. The characteristics listed above describe oils from the Williston and Michigan basins as well as Ordovician oils from Kansas and Oklahoma.

  19. Stratigraphy, structure, and extent of the East Continent Rift Basin

    SciTech Connect

    Wickstrom, L.H. )

    1992-01-01

    The proven existence of pre-Mt. Simon sedimentary rocks named the Middle Run Formation in southwestern Ohio led to the establishment of the Cincinnati Arch Consortium, a joint industry-government partnership to investigate the areal extent, nature, and origin of this new unit. Utilizing available well, seismic, and potential-field data, the consortium has shown that the Middle Run was deposited in a Precambrian rift basin, named the East Continent Rift Basin (ECRB). These data indicate the ECRB assemblage consists of a large folded and faulted wedge of interlayered volcanic and sedimentary rocks, unconformably overlain by Cambrian strata. This wedge is estimated to be thickest (up to about 22,000 feet) on the western edge, where it is in fault contact with Grenville Province rocks. To the west, the ECRB may extend as far as central Illinois and postdates the Precambrian Granite-Rhyolite Province rocks. The contact between the ECRB and this older province appears to be in part an angular unconformity and in part block faulted. The northern limit of this basin was not encountered in the study area; this may indicate a connection with the Midcontinent Rift in Michigan. In central Kentucky, the boundary conditions are more complex. It appears that the ECRB is constricted between a large block of the Granite-Rhyolite Province to the west and the Grenville Front on the east. Large Cambrian extensional structures (Rough Creek Graben and Rome Trough) were overprinted on the Granite-Rhyolite and Grenville Provinces. The ECRB may have acted as a stable block between these Cambrian features. The relationships of the ECRB to overlying Paleozoic features may be profound. Indeed, the ECRB may prove to be the reason for the very existence of the Cincinnati and Kankakee Arches.

  20. Drifting continents and endemic goitre in northern Pakistan.

    PubMed Central

    Stewart, A G

    1990-01-01

    Although Baltistan, north east Pakistan, is in a region of iodine deficiency disorders, the distribution of goitre within the district, according to age and sex, has not been clearly defined. To establish the prevalence of the condition and to measure the reported difference in prevalence in the north and south of the district thyroid size was assessed in new patients attending the Aman clinic, Khapalu, and outlying areas between April and September from 1981 to 1986. Samples of potable water collected from villages were analysed for iodine (as iodide) concentrations in Britain. Population weighted prevalences were: in the north in males 20.4%, in females 28.1% and in the south in males 13.9%, in females 21.2%. There was an overall deficiency of iodine in the water (mean iodine (as iodide) concentrations (north) 11.0 nmol/l (1.4 micrograms/l), (south) 11.8 nmol/l (1.5 micrograms/l) (95% confidence interval -0.7 to 0.9). The differences followed the Main Karakoram Thrust, suggesting a geological goitrogen in the north, which might be minerals containing ions such as BF4- and SO3F-, and molybdenite and calcium, which are present in rocks in Baltistan. A new hypothesis for the genesis of endemic goitre is proposed--that is, that continents on crustal plates drift across the earth and collide, one plate sliding under the other and melting, giving rise to characteristic mineral assemblages in the overlying rocks. As the minerals weather out they enter the diet of the local population, where in the presence of iodine deficiency they produce or enhance iodine deficiency disorders. Despite the current iodised oil campaign by the Pakistani government with Unicef a long term working iodisation programme is still urgently needed. PMID:2372605

  1. Intraplate termination of transform faulting within the Antarctic continent

    NASA Astrophysics Data System (ADS)

    Storti, F.; Salvini, F.; Rossetti, F.; Phipps Morgan, J.

    2007-08-01

    The sector of Antarctica facing Australia east of 139 °E is characterized by the abundance of exceptionally long oceanic fracture zones that are collinear to post-rift right-lateral strike-slip fault systems developed at the northeastern edge of the Antarctic continent. High-resolution reflection seismic profiles indicate recent strike-slip activity at the southeastern edge of the Balleny Fracture Zone, similar to what is observed onshore in North Victoria Land. The architecture, kinematics, and timing of this intraplate deformation at the northeastern edge of Antarctica cannot be reconciled with typical plate tectonic kinematics, in particular, with a classical divergent plate boundary environment. Here we show that combined geological and geophysical data in northeastern Antarctica support the post-rift southeastward reactivation of the passive margin east of 139 °E along intraplate right-lateral strike-slip deformation belts. These deformation belts include oceanic transform faults and their collinear oceanic fracture zone and continental shear zone extensions. A striking consequence is that there is intraplate accommodation of transform fault slip in this region of Earth's surface along fracture zones and a long-active region of intracontinental deformation that is 'reusing' prior plate boundary fault zones. As the intraplate termination of plate boundary transform faulting is not predicted by classical plate tectonic theory; this region is one of the most clear examples of the transition from rigid to semi-rigid plate tectonic deformation during the formation and long-lived incubation of a potential new plate boundary.

  2. Northern and eastern margins of the Siberian continent in Triassic

    SciTech Connect

    Egorov, A.Yu. )

    1993-09-01

    Siliciclastic sedimentation has been predominant on the northern and eastern margins of the Siberian continent since the Triassic period. Seven transgression-regression cycles can be recognized in the Triassic succession: Griesbachien-Dienerian, Smithian-Low Spathian, Upper Spathian, Anissian (with subcycles), Ladian, Carnian, and Norlan (with subcycles). All zonal units were distinguished within transgressive portions of the cycles. Regressive portions of the cycles formed practically instantaneously. Very high sedimentation rate (300-3000 mm/1000 yr), specific structures of sedimentary rocks, and distribution of unconformities led to the conclusion that active avalanche sedimentation at the basin margins was of major significance. six facies regions are recognized in the sedimentation area: Taimyr, Kotuy-Anabar, Leno-Anabar, Bur-Olenek, Verkhoyansk, and Novosibirsk (New Siberian Islands). The main source areas were located at the Patoma Mountains for the eastern margin and at the Anabar anticline and Olenek uplift for the northern margin. Most sediments were transported to the eastern margin by a large river with a huge delta which was similar in size to the modern Lena's delta. Sediments were further distributed by contour streams. Local synsedimentary structures controlled the paleogeography of the entire area. The paleogeographical evolution of the eastern margin is the history of this delta development. The rifting activities with the trappean magmatism were the main events at the northern margin, especially in the Talmyr area. The pelagic sedimentation has been predominant in the New Siberian Islands area and most of the Laptev Sea aquatoria. The organic-rich sediments have been distinguished in Low Olenekian (Smithian), Low Anissian, Low Ladinian, and Low Carnian substages. Most of them could be hydrocarbon source rocks. Triassic oil and gas seeps have been discovered at the northern portion of the Vilyui syncline, near the Lena's delta and the Nordvic Bay.

  3. Preparation of northern mid-continent petroleum atlas

    SciTech Connect

    Gerhard, L.C.; Carr, T.R.; Watney, W.L.

    1997-02-13

    The prototype Digital Petroleum Atlas (DPA) Project is part of a long-term effort to develop a new methodology to provide efficient and timely access to the latest petroleum data and technology for the domestic oil and gas industry, public sector research organizations and local governmental units. The DPA provides real-time access through the Internet using widely available tools such as World-Wide-Web browsers. The latest technologies and information are published electronically when individual project components are completed removing the lag and expense of transferring technology using traditional paper publication. Active links, graphical user interfaces and database search mechanisms of the DPA provide a product with which the operator can interact in ways that are impossible in the paper publication. Contained in the DPA are forms of publication that can only be displayed in an electronic environment (for example, animated exploration histories through time). Improvement in data and technology access for the domestic petroleum industry represents one of the best and cost-effective options that is available for mitigating the continued decline in domestic production. The prototype DPA concentrated on developing methodologies and computerized procedures to generate and to publish a limited set of field and play studies concentrated in Kansas and to a lesser extent the Northern Mid-continent. Access is provided through the DPA to previously existing and new regional, play, field and individual well information. Methodologies, developed in year one of the prototype DPA Project, provide a published product and ongoing technology transfer activity that is continuously updated with the latest information and technology.

  4. Architecture and Kinematics of the Taiwan Arc-Continent Collision

    NASA Astrophysics Data System (ADS)

    Carena, S.; Suppe, J.; Wu, Y. M.; Kanda, R. V. S.

    2014-12-01

    In Taiwan two subduction zones come together in quasi-orthogonal, kinematically stable configuration. Under Taiwan the upper crust of Eurasia is decoupled from the rest of the lithosphere by a detachment that forms the main subduction interface between Eurasia (EU) and Philippine Sea plate (PSP). This interface is visible in both seismicity and crustal tomography at shallow depths and can be followed into the mantle to depths of 450-500 km using global tomography. The plate interface between EU and PSP in the upper 100 km changes from about 60 degrees in the south to vertical (south-central Taiwan) to overturned (north-central Taiwan). The Eurasian Moho is similarly folded, but it does not overturn. Shortening across the plate boundary is accomplished by a combination of subduction of Eurasian lithosphere, folding and thrusting in the Eurasian upper crust, and a secondary subduction zone within the PSP. We hypothesize that: (1) once arc-continent collision occurs, subduction of Eurasian continental lower crust and upper mantle can continue by lithospheric delamination and by continuity with the much larger Eurasian slab to the south; (2) the upper crust of EU deforms by faulting and folding; (3) the present convergence rate of about 90 mm/yr is limited to the last 2 Ma, whereas the long-term rate is about 30 mm/yr and in Taiwan the difference is being taken up by secondary subduction within the PSP margin; (4) a margin-parallel STEP (Subduction-Transform-Edge-Propagator) fault forms the northern limit of Eurasian subduction, which allows the whole system to propagate self-similarly southwestward.

  5. Smoke aerosol transport patterns over the Maritime Continent

    NASA Astrophysics Data System (ADS)

    Xian, Peng; Reid, Jeffrey S.; Atwood, Samuel A.; Johnson, Randall S.; Hyer, Edward J.; Westphal, Douglas L.; Sessions, Walter

    2013-03-01

    Smoke transport patterns over the Maritime Continent (MC) are studied through a combination of approaches, including a) analyzing AODs obtained from satellite products; b) aerosol transport modeling with AOD assimilation along with the atmospheric flow patterns; c) analyzing smoke wet deposition distributions; and d) examining forward trajectories for smoke events defined in this study. It is shown that smoke transport pathways are closely related to the low-level atmospheric flow, i.e., during June-Sept, smoke originating from the MC islands with a dominant source over central and southern Sumatra, and southern and western Borneo, is generally transported northwestward south of the equator and northeastward north of the equator with the cross-equatorial flow, to the South China Sea (SCS), the Philippines and even further to the western Pacific. During the October-November transitional period, smoke transport paths are more zonally oriented compared to June-September. Smoke originating from Java, Bali, Timor etc, and southern New Guinea, which are in the domain of easterlies and southeasterlies during the boreal summer (June-November), is generally transported westward. It is also found that smoke transport over the MC exhibits multi-scale variability. Smoke typically lives longer and can be transported farther in El Niño years and later MJO phases compared with non El Niño years and earlier MJO phases. During El Niño periods there is much stronger westward transport to the east tropical Indian Ocean. Finally, orographic effect on smoke transport over the MC is also clearly discernable.

  6. Continent-continent collision at the Pacific/Australian plate boundary: Lithospheric deformation, mountain building, and subsequent scientific endeavors

    NASA Astrophysics Data System (ADS)

    Okaya, D. A.; Stern, T. A.; Davey, F. J.

    2012-12-01

    Continental collision occurs at strike-slip plate boundaries where transform motion and oblique convergence create processes of surficial mountain building and deformation within the deeper crust and lithospheric mantle. The Pacific/Australian transform plate boundary in South Island, New Zealand, is characterized by active oblique continent-continent collision with an associated Southern Alps orogen that exhibits both high exhumation rates and rapid strike-slip movement. Beginning in the 1990s, this system was the focus of a decade-long collaborative USA-New Zealand multi-disciplinary study to understand lithospheric structure and processes involved in this transpression. Funded primarily by the NSF Continental Dynamics program and the New Zealand Science Foundation, this project known as SIGHT (South Island Geophysical Transect) with its companion SAPSE (Southern Alps Passive Seismic Experiment) included the following disciplines that involved substantial field observation experiments: seismic reflection, explosion refraction, onshore-offshore wide-angle reflection/refraction, regional and teleseismic passive seismology, magnetotellurics, laboratory petrophysics, gravity, regional geological investigations, and rheological analyses. More than fifty scientists and students from both nations participated in the combined set of studies that have led to over forty-five journal publications, an AGU Monograph, and a dozen graduate theses. Primary results of the project indicate the Pacific-Australian strike-slip plate boundary (Alpine fault) is not vertical but is eastward dipping and rheologically weak based on diverse geophysical data. Most deformation is within the Pacific plate that hosts the Southern Alps orogen. High mantle seismic velocities vertically disposed beneath the orogen suggest Pacific and perhaps Australian mantle lithosphere contribute to a zone of plate-boundary-parallel distributed mantle shortening. The crustal root of the overlying Southern Alps

  7. Improving continence services for older people from the service-providers’ perspective: a qualitative interview study

    PubMed Central

    Orrell, Alison; McKee, Kevin; Dahlberg, Lena; Gilhooly, Mary; Parker, Stuart

    2013-01-01

    Objective To examine in depth the views and experiences of continence service leads in England on key service and continence management characteristics in order to identify and to improve our understanding of barriers to a good-quality service and potential facilitators to develop and to improve services for older people with urinary incontinence (UI). Design Qualitative semistructured interviews using a purposive sample recruited across 16 continence services. Setting 3 acute and 13 primary care National Health Service Trusts in England. Participants 16 continence service leads in England actively treating and managing older people with UI. Results In terms of barriers to a good-quality service, participants highlighted a failure on the part of commissioners, managers and other health professionals in recognising the problem of UI and in acknowledging the importance of continence for older people and prevalent negative attitudes towards continence and older people. Patient assessment and continence promotion regardless of age, rather than pad provision, were identified as important steps for a good-quality service for older people with UI. More rapid and appropriate patient referral pathways, investment in service capacity, for example, more trained staff and strengthened interservice collaborations and a higher profile within medical and nurse training were specified as being important facilitators for delivering an equitable and high-quality continence service. There is a need, however, to consider the accounts given by our participants as perhaps serving the interests of their professional group within the context of interprofessional work. Conclusions Our data point to important barriers and facilitators of a good-quality service for older people with UI, from the perspective of continence service leads. Further research should address the views of other stakeholders, and explore options for the empirical evaluation of the effectiveness of identified service

  8. Quaternary Reorganization of North American Mid-continent Drainage Systems

    NASA Astrophysics Data System (ADS)

    Carson, E. C.; Rawling, J. E., III; Attig, J. W.; Bates, B. R.

    2013-12-01

    Identification of ancestral drainage systems in the North American mid-continent has been a topic of research and debate among geologists since the middle of the 19th Century. Over time our understanding of the significance of Quaternary glaciations in reshaping drainage patterns has grown. The ancestral Teays River, which drained large areas of the central Appalachians and flowed westward across Indiana and western Illinois, was dammed multiple times by Quaternary glaciers before finally being rerouted to the course of the modern central Ohio River. Similarly, the northward-flowing ancestral Pittsburgh River was dammed by pre-Illinoian glaciers; subsequent stream piracy converted this river system into the modern Allegheny, Monongahela and uppermost Ohio Rivers. Deposits and geomorphic features along the westward-flowing lower Wisconsin River indicate that the modern upper Mississippi River and Wisconsin River may have experienced a similar history of ice blockage, stream piracy, and radical rerouting. Coring into the Bridgeport strath terrace along the lower Wisconsin River reveals that the bedrock surface dips to the east, indicating the valley was cut by an eastward-flowing river. We believe the most likely scenario following this interpretation is that an ancestral river flowing along the modern upper Mississippi River valley made a sharp bend at Prairie du Chien, WI, and flowed eastward along the valley occupied by the modern lower Wisconsin River. This river, referred to here as the Wyalusing River, likely flowed northeastward into the Great Lakes (St. Lawrence) drainage until that path was blocked by ice advancing from the northwest. Subsequent stream piracy immediately south of the modern confluence of the Mississippi and Wisconsin Rivers rerouted these streams, converting them to the headwaters of the greater Mississippi drainage. The combined rerouting of these river systems into entirely different drainage basins necessitates significant fundamental

  9. The thermal influence of continents on a model-generated January climate

    NASA Technical Reports Server (NTRS)

    Spar, J.; Cohen, C.; Wu, P.

    1981-01-01

    Two climate simulations were compared. Both climate computations were initialized with the same horizontally uniform state of rest. However, one is carried out on a water planet (without continents), while the second is repeated on a planet with geographically realistic but flat (sea level) continents. The continents in this experiment have a uniform albedo of 0.14, except where snow accumulates, a uniform roughness height of 0.3 m, and zero water storage capacity. Both runs were carried out for a 'perpetual January' with solar declination fixed at January 15.

  10. Continent-ocean chemical heterogeneity in the mantle based on seismic tomography.

    PubMed

    Forte, A M; Dziewonski, A M; O'connell, R J

    1995-04-21

    Seismic models of global-scale lateral heterogeneity in the mantle show systematic differences below continents and oceans that are too large to be purely thermal in origin. An inversion of the geoid, based on a seismic model that includes viscous flow in the mantle, indicates that the differences beneath continents and oceans can be accounted for by differences in composition in the upper mantle superposed on mantle-wide thermal heterogeneities. The net continent-ocean density differences, integrated over depth, are small and cause only a low flux of mass and heat across the asthenosphere and mantle transition zone. PMID:17746544

  11. The continent-ocean transition of the Pearl River margin

    NASA Astrophysics Data System (ADS)

    Cameselle, A. L.; Ranero, C. R.; Franke, D.; Barckhausen, U.

    2013-12-01

    Rifted continental margins form by lithospheric extension and break-up. The continent to ocean transition (COT) architecture depends on the interplay between tectonic and magmatic processes, and thus, to study the COT variability of different systems is key to understand rifting. We use MCS data and magnetic lineations across the Pearl River margin (PRM) of South China Sea to investigate a previously poorly defined COT. The structure of the PRM presents different amounts of extension allowing the study of conjugate pairs of continental margins and their COT in a relative small region. We reprocessed about 2250 km of MCS data along 4 regional, crustal-scale lines and found that 3 of them possibly display the COT. The time-migrated seismic sections show differences in internal reflectivity, faulting style, fault-block geometry, the seismic character of the top of the basement, in the geometry of sediment deposits, and Moho reflections, that we interpret to represent clear continental and oceanic domains. The continental domain is characterized by arrays of normal faults and associated tilted blocks overlaid by syn-rift sedimentary units. The Moho is imaged as sub-horizontal reflections that define a fairly continuous boundary typically at 8-10 s TWT. Estimation of the thickness of the continental crust using 6 km/s average velocity indicates a ~22 km-thick continental crust under the uppermost slope passing abruptly to ~9-6 km under the lower slope. Comparatively the oceanic crust has a highly reflective top of basement, little-faulting, not discernible syn-tectonic strata, and fairly constant thickness (4-8 km) defined by usually clear Moho reflections. The COT occurs across a ~5-10 km narrow zone. Rifting resulted in asymmetric conjugate margins. The PRM shows arrays of tilted fault blocks covered by abundant syn-rift sediment, whereas the conjugate Macclesfield Bank margin displays abrupt thinning and little faulting. Seismic profiles also show a change in the

  12. Flexural Tectonics in Continents: Critical Stress amid Immeasurable Strain

    NASA Astrophysics Data System (ADS)

    Bilham, R. G.

    2012-12-01

    With a few notable exceptions, most fatalities from earthquakes in the past millennium have occurred in mid-continent regions along the southern edge of the Eurasian plate where earthquakes are not expected due to their infrequency, or absence, in local historical records. Although the spatial density geodetic measurement in many parts of the Indo-Eurasian collision zone is currently poor, geodetically estimated strain rates where these are sufficiently dense (e.g. North America) are now being considered an important option to quantify the stressing rate of regions where seismic productivity is low. Certain assumptions attend the use of surface strain as a measure of seismic productivity: that the observed surface strain rate provides a measure of strain at seismogeninc depths, that none of the observed strain is dissipated in aseismic processes, that currently measured rates are uniform in time, and perhaps most importantly, whether regional strain rate alone is an adequate measure of the failure process. The first of these assumptions can be violated in locations in continental collisional settings, such as India, where flexural stresses prevail. The minimum in-plane northerly directed compressional stress in the Indian plate required to support the Tibetan Plateau is overwhelmed by the flexural stresses caused by the depression of its northern edge. Flexure results in static stresses that vary with depth and latitude, but which, averaged over the entire plate vary negligibly with time, because the rocks of India stream through the >600 km wavelength flexural stress-field at rates of only 2 cm/yr. This theoretical result is consistent with India's mean north-south strain rate observed geodetically, which is less than a few nanostrain each year. The spatial distribution of flexural stress, however, varies spatially as a function of distance from the Himalayan front. Strain rates exceed 2 bars/km in a flexural trough between 1000-1800 km south of the Himalaya, and

  13. Correlation between mobile continents and elevated temperatures in the subcontinental mantle

    NASA Astrophysics Data System (ADS)

    Jain, Charitra; Rozel, Antoine; Tackley, Paul

    2016-04-01

    Rolf et al. (EPSL, 2012) and Coltice et al. (Science, 2012) have previously shown that continents exert a first order influence on Earth's mantle flow by affecting convective wavelength and surface heat flow. With stationary continents, Heron and Lowman (JGR, 2014) highlighted the decreasing role of continental insulation on subcontinental temperatures with higher Rayleigh number (Ra). However, the question whether there exists a correlation between mobile continents and elevated temperatures in the subcontinental mantle or not remains to be answered. By systematically varying parameters like core-mantle boundary (CMB) temperature, continental size, and mantle heating modes (basal and internal); we model thermo-chemical mantle convection with 2D spherical annulus geometry (Hernlund and Tackley, PEPI 2008) using StagYY (Tackley, PEPI 2008). Starting with a simple incompressible model having mobile continents, we observe this correlation. Furthermore, this correlation still holds when the model complexity is gradually increased by introducing internal heating, compressibility, and melting. In general, downwellings reduce the mantle temperature away from the continents, thereby resulting in correlation between mobile continents and elevated temperatures in the subcontinental mantle. For incompressible models (Boussinesq approximation), correlation exists and the dominant degree of convection varies with the continental distribution. When internal heating is switched on, correlation is observed but it is reduced as there are less cold regions in the mantle. Even for compressible models with melting, big continents are able to focus the heat underneath them. The dominant degree of convection changes with continental breakup. Additionally, correlation is observed to be higher in the upper mantle (300 - 1000 km) compared to the lower mantle (1000 - 2890 km). At present, mobile continents in StagYY are simplified into a compositionally distinct field drifting at the top of

  14. Effect of Nerve-Sparing Radical Prostatectomy on Urinary Continence in Patients With Preoperative Erectile Dysfunction

    PubMed Central

    2016-01-01

    Purpose: We aimed to assess whether nerve-sparing radical prostatectomy (nsRP) is associated with improved recovery of urinary continence compared to non–nerve-sparing radical prostatectomy (nnsRP) in patients with localized prostate cancer and preoperative erectile dysfunction. Methods: A total of 360 patients with organ-confined prostate cancer and an International Index of Erectile Function score of less than 17 were treated with nsRP or nnsRP in Seoul St. Mary’s Hospital. Patients who received neoadjuvant or adjuvant androgen deprivation therapy or had a history of prostate-related surgery were excluded. Recovery of urinary continence was assessed at 0, 1, 3, 6, and 12 months. Postoperative recovery of continence was defined as zero pad usage. The association between nerve-sparing status and urinary continence was assessed by using univariate and multivariate Cox regression analyses after controlling for known predictive factors. Results: Urinary continence recovered in 279 patients (77.5%) within the mean follow-up period of 22.5 months (range, 6–123 months). Recovery of urinary continence was reported in 74.6% and 86.4% of patients after nnsRP and nsRP, respectively, at 12 months (P=0.022). All groups had comparable perioperative criteria and had no significant preoperative morbidities. Age, American Society of Anesthesiologists score, and nerve-sparing status were significantly associated with recovery of urinary continence on univariate analysis. On multivariate analysis, age (hazard ratio [HR], 1.254; 95% confidence interval [CI], 1.002–1.478; P=0.026) and nerve-sparing status (HR, 0.713; 95% CI, 0.548–0.929; P=0.012) were independently associated with recovery of urinary continence. Conclusions: nsRP, as compared to nnsRP, improves recovery rates of urinary incontinence and decreases surgical morbidity without compromising pathologic outcomes. PMID:27032560

  15. The Ocean-Continent Boundary Effect on Seismic Noise Recorded on Land

    NASA Astrophysics Data System (ADS)

    Stutzmann, E.; Gualtieri, L.; Capdeville, Y.; Farra, V.; Mangeney, A.

    2014-12-01

    Seismic noise in the period band 3-10s is generated at the surface of the ocean by the interaction of ocean gravity waves. Noise signal is dominated by Rayleigh waves and is recorded worldwide, both on the ocean seafloor and on continent. Microseismic Rayleigh waves, like any other elastic wave, loose energy when traveling from the ocean to the continent. Thus, the noise records on continent are affected by the propagation of microseismic waves, especially across the boundary between the ocean and the continent, the main structural boundary along the source-receiver path. At the ocean-continent boundary, Rayleigh waves dissipate a significant amount of energy (e.g. McGarr, 1969) and noise Love waves may be generated (e.g. Gregersen, 1977). In order to investigate the effect of the ocean-continent boundary on seismic noise records, we simulate the propagation of the seismic wavefield across the seafloor using the spectral-element method in the secondary microseismic period band (3-10s). A single noise source is located at the surface of the ocean and the signal is recorded at the seafloor, both in deep and shallow ocean regions and on continent. The seismograms computed in a model with continental slope are compared to those computed in a model with flat seafloor, for varying periods and slopes. In the presence of the continental slope, the seismic records are affected by a secondary virtual source, generated by the seafloor topography. The effect of the spatial distribution of noise sources is also investigated.

  16. Representations of OxyContin in North American newspapers and medical journals

    PubMed Central

    Whelan, Emma; Asbridge, Mark; Haydt, Susan

    2011-01-01

    BACKGROUND: There are public concerns regarding OxyContin (Purdue Pharma, Canada) and charges within the pain medicine community that media coverage of the drug has been biased. OBJECTIVE: To analyze and compare representations of OxyContin in medical journals and North American newspapers in an attempt to shed light on how each contributes to the ‘social problem’ associated with OxyContin. METHODS: Using searches of newspaper and medical literature databases, two samples were drawn: 924 stories published between 1995 and 2005 in 27 North American newspapers, and 197 articles published between 1995 and 2007 in 33 medical journals in the fields of addiction/substance abuse, pain/anesthesiology and general/internal medicine. The foci, themes, perspectives represented and evaluations of OxyContin presented in these texts were analyzed statistically. RESULTS: Newspaper coverage of OxyContin emphasized negative evaluations of the drug, focusing on abuse, addiction, crime and death rather than the use of OxyContin for the legitimate treatment of pain. Newspaper stories most often conveyed the perspectives of law enforcement and courts, and much less often represented the perspectives of physicians. However, analysis of physician perspectives represented in newspaper stories and in medical journals revealed a high degree of inconsistency, especially across the fields of pain medicine and addiction medicine. CONCLUSION: The prevalence of negative representations of OxyContin is often blamed on biased media coverage and an ignorant public. However, the proliferation of inconsistent messages regarding the drug from physicians plays a role in the drug’s persistent status as a social problem. PMID:22059195

  17. Heat Flow Partitioning Between Continents and Oceans - from 2D to 3D

    NASA Astrophysics Data System (ADS)

    Moresi, L. N.; Cooper, C. M.; Lenardic, A.

    2010-12-01

    Scalings derived from thermal network theory explain how the presence of continents can influence the Earth’s overall heat loss. Intuitively, it may seem that increasing the proportion of a planet’s surface area covered by continents would decrease the efficiency of heat transfer given that continents do not participate in convective overturn. However, this ignores the potential feedback between the insulating effect of continents and the temperature-dependent viscosity of the mantle (Lenardic et al, 2005, Cooper et al, 2007). When this feedback is considered, a clear regime exists in which the partial stagnation and insulation of the surface by buoyant continental crust can lead to an increase in heat flow compared to the uninsulated case. The numerical results used to verify the scalings have mostly been conducted in two dimensions in order to cover a very wide range of Rayleigh number, fraction of continental coverage, and continental thickness. However as more recent results show that the configuration of the crust also plays a role in determining the heat flow partitioning and global heat flow (See Lenardic et al, “Continents, Super-Continents, Mantle Thermal Mixing, and Mantle Thermal Isolation” in this session), we have begun to repeat this exhaustive and exhausting 2D study in 3D. Cooper, C.M., A. Lenardic, and L.-N. Moresi "Effects of continental insulation and the partioning of heat producing elements on the Earth's heat loss." Geophys. Res. Lett., 33 ,10.1029, 2006. Lenardic, A., L.-N. Moresi, A.M. Jellinek, and M. Manga "Continental insulation, mantle cooling, and the surface area of oceans and continents." Earth Planet. Sci. Lett., 234 ,317-333, 2005.

  18. The Interaction of Eastward Propagating Equatorial Modes with the Maritime Continent

    NASA Astrophysics Data System (ADS)

    Flatau, M. K.

    2015-12-01

    We examine the processes that contribute to blocking of the eastward propagating equatorial modes by the Maritime Continent. The recent study by Baranowski at al (2015) have shown that the propgation of Kelvin waves through the Maritime Continent is strongly influenced by the interaction of the waves with the diurnnal cycle of convection over the land which can either amplify or supress the convective forcing of the wave. This suggests that inorder for the wave to cross the Maritime Continent it has to be in phase with local convection. Another possible mechanism through which the Maritime Continent can influence approaching Kelvin waves and MJO's is their interacton with cyclonic disturbances generated by the lee vortices at the tips of Sumatra. Both of these mechanisms can be misrepresented by dynamic models and contribute to predictability barrier in this region These equatorial modes ate examined in Navy models forecasts of DYNAMO MJOs and n idealized experiments. While the models appear to predict the MJO and Kelvin wave approach to the Maritime continent their propagation is too slowa andn westward propagating disturbance are often too strong. We examine the contribution of lee vortices and local diurnal convection variability to this process

  19. Quality audit--a review of the literature concerning delivery of continence care.

    PubMed

    Swaffield, J

    1995-09-01

    This paper outlines the role of quality audit within the framework of quality assurance, presenting the concurrent and retrospective approaches available. The literature survey provides a review of the limited audit tools available and their application to continence services and care delivery, as well as attempts to produce tools from national and local standard setting. Audit is part of a process; it can involve staff, patients and their relatives and the team of professionals providing care, as well as focusing on organizational and management levels. In an era of market delivery of services there is a need to justify why audit is important to continence advisors and managers. Effectiveness, efficiency and economics may drive the National Health Service, but quality assurance, which includes standards and audit tools, offers the means to ensure the quality of continence services and care to patients and auditing is also required in the purchaser/provider contracts for patient services. An overview and progress to date of published and other a projects in auditing continence care and service is presented. By outlining and highlighting the audit of continence service delivery and care as a basis on which to build quality assurance programmes, it is hoped that this knowledge will be shared through the setting up of a central auditing clearing project. PMID:7551434

  20. Cecal rupture after continent ileocecal urinary diversion during total pelvic exenteration

    SciTech Connect

    Brand, E. )

    1991-09-01

    Continent ureteral diversion at the time of pelvic exenteration avoids an external appliance and allows patients to retain bladder reservoir function. The technical difficulty of this procedure requires meticulous attention to operative and perioperative care, particularly after pelvic irradiation. A patient with recurrent stage IIIB carcinoma of the cervix underwent total pelvic exenteration with reconstructive procedures including low rectal anastomosis, neovagina formation, and ileocecal (Indiana) continent diversion. Early catheterization of the reservoir began 2 weeks postoperatively. One week later cecal rupture occurred, not related to suture line (technical) failure. Because of the high wall tension and reduced compliance in the irradiated cecum, the authors do not recommend catheterization of the urinary reservoir before 4-6 weeks. In order for continent diversion to become the standard diversion in exenteration patients, the major complication rate must remain comparable to that of noncontinent diversion.

  1. What caused the recent ``Warm Arctic, Cold Continents'' trend pattern in winter temperatures?

    NASA Astrophysics Data System (ADS)

    Sun, Lantao; Perlwitz, Judith; Hoerling, Martin

    2016-05-01

    The emergence of rapid Arctic warming in recent decades has coincided with unusually cold winters over Northern Hemisphere continents. It has been speculated that this "Warm Arctic, Cold Continents" trend pattern is due to sea ice loss. Here we use multiple models to examine whether such a pattern is indeed forced by sea ice loss specifically and by anthropogenic forcing in general. While we show much of Arctic amplification in surface warming to result from sea ice loss, we find that neither sea ice loss nor anthropogenic forcing overall yield trends toward colder continental temperatures. An alternate explanation of the cooling is that it represents a strong articulation of internal atmospheric variability, evidence for which is derived from model data, and physical considerations. Sea ice loss impact on weather variability over the high-latitude continents is found, however, to be characterized by reduced daily temperature variability and fewer cold extremes.

  2. Correlation Between Mobile Continents and Elevated Temperatures in the Subcontinental Mantle

    NASA Astrophysics Data System (ADS)

    Jain, C.; Rozel, A. B.; Tackley, P.

    2015-12-01

    Rolf et al. (EPSL, 2012) and Coltice et al. (Science, 2012) have previously shown that continents exert a first order influence on Earth's mantle flow by affecting convective wavelength and surface heat flow. With stationary continents, Heron and Lowman (JGR, 2014) highlighted the decreasing role of continental insulation on subcontinental temperatures with higher Rayleigh number (Ra). However, the question whether there exists a correlation between mobile continents and elevated temperatures in the subcontinental mantle or not remains to be answered. Continental motion is attributed to the viscous stresses imparted by the convecting mantle and the extent of this motion depends on the heat budget of the mantle. Core-mantle boundary (CMB) heat flux, internal heating from decay of radioactive elements, and mantle cooling contribute to this heat budget. Out of these sources, CMB heat flux is not well defined. However, the recent determination of core's high thermal conductivity requires a CMB heat flow of at least 12 TW (de Koker et al., PNAS 2012; Pozzo et al., Nature 2012; Gomi et al., PEPI 2013). Thus it is necessary to characterize the impact of basal heating on mantle dynamics with mobile continents and self-consistent plate tectonics. By systematically varying parameters such as CMB temperature, continental size, mantle heating modes, and Rayleigh number; we model Boussinesq, incompressible, thermo-chemical mantle convection with 2D spherical annulus geometry using StagYY (Tackley, PEPI 2008). We observe the aforementioned correlation irrespective of the variations in basal heating and continental size (except for very small continents). Moreover, we see episodicity between correlation-anticorrelation with increasing convective vigour. Furthermore, the effect of radioactivity in the continental crust on this correlation is investigated. At present, mobile continents in StagYY are simplified into a compositionally distinct field drifting at the top of the mantle

  3. Impact of Posterior Urethral Plate Repair on Continence Following Robot-Assisted Laparoscopic Radical Prostatectomy

    PubMed Central

    Kim, Isaac Yi; Hwang, Eun A; Mmeje, Chinedu; Ercolani, Matthew

    2010-01-01

    Purpose The objective of this study is to evaluate the continence rate following reconstruction of the posterior urethral plate in robot-assisted laparoscopic radical prostatectomy (RLRP). Materials and Methods A retrospective analysis of 50 men with clinically localized prostate cancer who underwent RLRP was carried out. Twenty-five patients underwent RLRP using the reconstruction of the posterior aspect of the rhabdosphincter (Rocco repair). Results of 25 consecutive patients who underwent RLRP prior to the implementation of the Rocco repair were used as the control. Continence was assessed at 7, 30, 90, and 180 days following foley catheter removal using the EPIC questionnaire as well as a follow-up interview with the surgeon. Results There was no statistically significant difference between the two groups in any of the patient demographics. At 7 days, the Rocco experimental group had a continence rate of 19% vs. 38.1% in the non-Rocco control group (p = 0.306). At 30 days, the continence rate in the Rocco group was 76.2% vs. 71.4% in the non-Rocco group (p = 1). At 90 days, the values were 88% vs. 80% (p = 0.718), respectively. At 180 days, the pad-free rate was 96% in both groups. Conclusion Rocco repair offers no significant advantage in the time to recovery of continence following RLRP when continence is defined as the use of zero pads per day. On the other hand, Rocco repair was associated with increased incidence of urinary retention requiring prolonged foley catheter placement. PMID:20376897

  4. The effects of size, configuration and distribution of continents on the efficiency of heat transport

    NASA Astrophysics Data System (ADS)

    Cooper, C. M.; Moresi, L. N.; Lenardic, A.

    2011-12-01

    The addition of continents to the surface of a planet alters its interior dynamics; understanding this alteration is critical to understanding the thermal evolution of the Earth. Specifically, the increase in temperature induced by continental insulation can be compensated by an increase in the heat loss through the overturn of the oceanic lithosphere, thus contradicting the predicted reduction of global heat loss due to presence of continents (e.g., Lenardic et al, 2005; Cooper et al, 2006; Lenardic et al, 2011). We reconfirm this counterintuitive result with three-dimensional simulations. In addition, we explore variations in the configuration of continents on the surface. Within simulations with equivalent continental coverage, but varying configuration, there is a competition between the lateral size of the blocks and the natural horizontal scale of the convection pattern which influences the stability of the models over time, and the efficiency of heat transport. Smaller continental blocks tend to induce a stable planform with upwellings permanently avoiding the blocks. However, in cases with larger continental blocks, the imposed scale is larger than the preferred scale of the convection pattern and upwellings are unable to avoid the blocks altogether. The dependency on stability and efficiency of heat transport within the Earth on continental coverage and configuration suggests continents can play a significant role in the Earth's heat budget and thermal history. Cooper, C.M., A. Lenardic, and L.-N. Moresi "Effects of continental insulation and the partioning of heat producing elements on the Earth's heat loss." Geophys. Res. Lett., 33 ,10.1029, 2006; Lenardic, A., C.M. Cooper, and L.-N. Moresi "A note on continents and the Earth's Urey ratio", Physics of the Earth and Planetary Interiors, 2011; Lenardic, A., L.-N. Moresi, A.M. Jellinek, and M. Manga "Continental insulation, mantle cooling, and the surface area of oceans and continents." Earth Planet. Sci

  5. The Making of Early Continents and the Initiation of Plate Tectonics on Earth

    NASA Astrophysics Data System (ADS)

    Rey, P. F.; Coltice, N.; Flament, N. E.

    2014-12-01

    We propose a simple, self-consistent model to explain a range of puzzling observation made in many Archean cratons including 1/ the marked petrological stratification of the lithospheric mantle; 2/ the multimodal polybaric volcanism of greenstone covers; 3/ the regional and temporal overlap between komatiitic-tholeiitic basalts and arc-volcanism; and 4/ the mid-lithospheric seismic discontinuity mapped across several cratons. This model also explains the possible transition from a stagnant-lid regime to a transient then steady-state plate tectonic regime. We performed several series of 2D thermo-mechanical numerical experiments to investigate the effect of an early continent on mantle convection. We considered a composite lid including 1/ a continent consisting of 55 km thick crust - made of TTG and continental flood basalts - above a 170-km-thick strongly depleted, strong and buoyant lithospheric mantle, and 2/ an oceanic lid including a 15-km-thick basaltic crust. These experiments show that the continent slowly spreads laterally toward the adjacent oceanic lid. The spreading and thinning of the continent drives exhumation of the fertile sub-continental mantle, which in turn promotes polybaric decompression melting producing komatiitic and tholeiitic basalts. Continental boudinage and rifting accompanying the spreading drives further upwelling and decompression melting to even shallower depths. This partial melting produces a moderately depleted mantle layer, progressively incorporated through cooling to the base of the continent. Our numerical experiments also show that spreading continents force the adjacent oceanic lid into the convective mantle, promoting subduction of the oceanic lid and temporal overlap between Archean komatiitic-tholeiitic basalts with arc-volcanism. Spreading and thinning of the continent lead to a sub-horizontal litho-tectonic fabric in the mantle, with a possible major discontinuity between the older strongly depleted mantle, and the

  6. Malone Antegrade Continence Enema in Patients with Perineal Colostomy After Rectal Resection.

    PubMed

    Wang, Jin-Hai; Xu, Jia-He; Ye, Feng; Xu, Xiang-Ming; Lin, Jian-Jiang; Chen, Wen-Bin

    2015-12-01

    The objective of this study was to evaluate the value of antegrade continence enema (Malone operation) in abdominoperineal resection (Miles' operation). Between January 2008 and May 2009, five cancer patients (two men and three women) underwent abdominoperineal resection and digestive reconstruction by perineal colostomy and Malone antegrade continence enema in our institution. Their functional results and quality of life were recorded. None of the patients died, but two had wound infections and one experienced urinary retention. Patients performed antegrade enema every 24 h with 2,000 mL of normal saline by themselves. The duration of the enema lasted for an average of approximately 35 min, and fecal contamination was not detected at 24 h. Patient satisfaction was determined to be 88 %. Malone antegrade continence enema associated with abdominoperineal resection and perineal colostomy provided acceptable continence. It preserved the body image of the patients and resulted in a satisfactory quality of life. It is a potential alternative for patients who are not willing to have a permanent colostomy. PMID:26730081

  7. Mechanisms and geologic significance of the mid-lithosphere discontinuity in the continents

    NASA Astrophysics Data System (ADS)

    Karato, Shun-Ichiro; Olugboji, Tolulope; Park, Jeffrey

    2015-07-01

    The stable continents have a puzzling structure. Recent seismological studies have revealed a marked drop in seismic velocity at middle-lithosphere depths, but a generally small velocity drop at the lithosphere-asthenosphere boundary. The mid-lithosphere discontinuity has previously been attributed to changes in composition and/or crystal alignment (anisotropy) caused by metasomatic alteration, as well as to partial melting and/or accretion of intruded materials that occurred after the formation of the continents. We show that these models cannot easily explain the global presence of a large seismic velocity drop in the middle lithosphere and a small velocity change at the lithosphere-asthenosphere boundary. These models are also difficult to reconcile with long-term continental stability and, in particular, observations of nearly depth-invariant ages of rocks in the continental lithosphere that do not support the notion of late alteration events. Instead, we propose an elastically accommodated grain-boundary sliding model that predicts a substantial velocity drop at the mid-lithosphere discontinuity and a weak seismic signal at the lithosphere-asthenosphere boundary, as observed, without invoking late-stage modifications to the lithosphere. In this model, the mid-lithosphere discontinuity is a general feature of the stable continents, the precise depth of which depends primarily on temperature and water content. Consequently, the depth of the mid-lithosphere discontinuity may provide clues to the evolution of continents.

  8. Profiles on Rural Education in the Seven State Mid-Continent Region.

    ERIC Educational Resources Information Center

    Missouri Univ., Columbia. Office of Social and Economic Data Analysis.

    Based on interviews with State Education Department personnel, this report presents information regarding the status of rural education in the seven-state region (Colorado, Kansas, Missouri, Nebraska, North Dakota, South Dakota, and Wyoming) served by the Mid-Continent Regional Laboratory. Of the 2,400 school districts in this region, 93 percent…

  9. Papers presented to the Conference on Heat and Detachment in Crustal Extension on Continents and Planets

    NASA Technical Reports Server (NTRS)

    1985-01-01

    Several topics relative to heat and detachment in crustal extension on continents and planets are discussed. Rifting on Venus, heat flow and continental breakup, magnetism, the mountains and tectonic processes of Io, and the ductile extension of planetary lithospheres are among the topics covered.

  10. Listening to carers talking about the subjects of continence and toileting.

    PubMed

    Forbat, Liz

    Toilets and continence play critical roles in the lives of people who care for a relative at home. Issues around toileting are central to the relationship between the carer and the person being cared for, with the bathroom often becoming the most important place in the house. PMID:14768154

  11. Modeled summer background concentration nutrients and suspended sediment in the mid-continent (USA) great rivers

    EPA Science Inventory

    We used regression models to predict background concentration of four water quality indictors: total nitrogen (N), total phosphorus (P), chloride, and total suspended solids (TSS), in the mid-continent (USA) great rivers, the Upper Mississippi, the Lower Missouri, and the Ohio. F...

  12. Extended Diaper Wearing: Effects on Continence in and out of the Diaper

    ERIC Educational Resources Information Center

    Tarbox, Rachel S. F.; Williams, W. Larry; Friman, Patrick C.

    2004-01-01

    Diaper use is widespread and possibly even increasing across diverse populations in the United States, ranging from infants to very old adults. We found no reports of an experimental analysis of the effect of wearing diapers on the frequency of urinary accidents and the attainment of continence skills (e.g., urinating in the toilet). In this…

  13. 21 CFR 876.5280 - Implanted mechanical/hydraulic urinary continence device.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... cuff to pass on the urethra. (b) Classification. Class III (premarket approval). (c) Date PMA or notice of completion of a PDP is required. A PMA or a notice of completion of a PDP is required to be filed... implanted mechanical/hydraulic urinary continence device shall have an approved PMA or a declared...

  14. Can individualized health care plans help increase continence in children with dysfunctional elimination syndrome?

    PubMed

    Boisclair-Fahey, Anne

    2009-10-01

    School-age children with dysfunctional elimination syndrome (DES) do not always have school support for their treatment plans, including an every 2-hr voiding schedule. The objective of this study was to increase school support of treatment plans by allowing access to bathrooms, thereby improving continence. An eight-question survey about bathroom access at schools was given to parents at baseline. The author contacted school nurses requesting that treatment plans be incorporated into individual health plans (IHPs) with teacher support of the IHP. Six weeks later, school nurses were contacted and parents completed a postintervention survey to determine whether IHPs were supported by teachers. Voiding diaries were used to document continence. Seventeen parents completed the survey at baseline, and 13 children were enrolled in the intervention. After the intervention, 100% of the children had IHPs and teacher support of treatment plans. Ninety-two percent had increased continence. IHPs improved teacher support of children's treatment plans and improved their continence. PMID:19342536

  15. Can Individualized Health Care Plans Help Increase Continence in Children with Dysfunctional Elimination Syndrome?

    ERIC Educational Resources Information Center

    Boisclair-Fahey, Anne

    2009-01-01

    School-age children with dysfunctional elimination syndrome (DES) do not always have school support for their treatment plans, including an every 2-hr voiding schedule. The objective of this study was to increase school support of treatment plans by allowing access to bathrooms, thereby improving continence. An eight-question survey about bathroom…

  16. Manipulation of the Family Photo Album: Esther Parada's Transplant--A Tale of Three Continents

    ERIC Educational Resources Information Center

    Eggemeyer, Valerie

    2004-01-01

    In this article, the author focuses on Esther Parada's non-traditional use of the Web to communicate her art, and offers a critique of Parada's work, "Transplant: A Tale of Three Continents," and suggestions for critiquing Web art in the school classroom. Parada creates an intersection between this new medium and the more traditional medium of…

  17. Mid-continent fall temperatures at the 10-cm soil depth

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Recommendations for applying N-fertilizer in autumn involve delaying applications until daily soil temperature at 10 cm depth is = or < 10° C. Daily soil temperature data during autumn were examined from 26 sites along a transect from 36° to 49° N latitude in the mid-continent USA. After soils first...

  18. Littoral and Shoreline Wood in Mid-continent Great Rivers (USA)

    EPA Science Inventory

    Less is known about the ecology of wood in great rivers than in smaller lotic systems. We used a probability survey to estimate the abundance of littoral and shoreline wood along the mid-continent great rivers of the United States: the Missouri, Upper Mississippi, and the Ohio Ri...

  19. Lost Continents? Children's Understanding of the Location and Orientation of the Earth's Land Masses.

    ERIC Educational Resources Information Center

    Wiegand, Patrick; Stiell, Bernadette

    1996-01-01

    Presents the results of an experiment that asked 53 middle school children to identify continent shapes and to arrange them to form a map of the world. Australia, Europe, and Asia were the most recognized. Misidentified and misaligned most consistently were Africa and Antarctica. Discusses possible reasons and teachers' responses. (MJP)

  20. Feldspar basalts in lunar soil and the nature of the lunar continents

    NASA Technical Reports Server (NTRS)

    Reid, A. M.; Ridley, W. I.; Harmon, R. S.; Warner, J.; Brett, R.; Jakes, P.; Brown, R. W.

    1974-01-01

    It is found that 25% on the Apollo-14 glasses have the same composition as the glasses in two samples taken from the Luna-16 column. The compositions are equivalent to feldspar basalt and anorthosite gabbro, and are similar to the feldspar basalts identified from Surveyor-7 analysis for lunar continents.

  1. A northern Cordilleran ocean-continent transect: Sitka Sound, Alaska, to Atlin Lake, British Columbia

    USGS Publications Warehouse

    Brew, D.A.; Karl, S.M.; Barnes, D.F.; Jachens, R.C.; Ford, A.B.; Horner, R.

    1991-01-01

    The 155 km wide, 310 km long Sitka Sound - Atlin Lake continent-ocean transect includes almost all the geologic, geophysical, and geotectonic elements of the Canadian Cordillera. It crosses the Chugach, Wrangellia, Alexander, Stikine, and Cache Creek terranes, the Gravina and Laberge overlap assemblages, intrusive and metamorphic belts, and neotectonic faults that bound major blocks. -from Authors

  2. 21 CFR 876.5280 - Implanted mechanical/hydraulic urinary continence device.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Implanted mechanical/hydraulic urinary continence device. 876.5280 Section 876.5280 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Therapeutic Devices § 876.5280 Implanted mechanical/hydraulic...

  3. Evaluation Plan of the Mid-continent Research for Education and Learning, FY1996-FY2000.

    ERIC Educational Resources Information Center

    Barley, Zoe

    This evaluation plan, which is updated annually, provides a synthesis of the various evaluation activities of Mid-continent Research for Education and Learning (McREL). During 1999, the fourth year of the Laboratory's contract period with the Office of Educational Research and Improvement, special studies and integrated studies were designed to…

  4. Rotational inertia of continents: A proposed link between polar wandering and plate tectonics

    USGS Publications Warehouse

    Kane, M.F.

    1972-01-01

    A mechanism is proposed whereby displacement between continents and the earth's pole of rotation (polar wandering) gives rise to latitudinal transport of continental plates (continental drift) because of their relatively greater rotational inertia. When extended to short-term polar wobble, the hypothesis predicts an energy change nearly equivalent to the seismic energy rate.

  5. Laparoscopic radical prostatectomy with bladder neck preservation: positive surgical margin and urinary continence status

    PubMed Central

    Jaskulski, Jaroslaw; Jarecki, Piotr; Dudek, Przemysław; Szopiński, Tomasz; Chłosta, Piotr

    2014-01-01

    Introduction Preservation of the bladder neck (BN) has been controversial, as limited excision of the bladder neck may result in incomplete resection of the disease. Moreover, the urinary continence rate may not be improved. Aim To evaluate the effect of bladder neck sparing on urinary continence, and surgical margins status in prostate cancer (PCa) patients treated with laparoscopic radical extraperitoneal prostatectomy. Material and methods A retrospective analysis of 295 consecutive patients who had undergone laparoscopic radical extraperitoneal prostatectomy for clinically localised prostate cancer in a single institution was performed. Positive surgical margin (SM(+)) and urinary continence status at 3, 6, and 12 months were evaluated. Results The distribution of SM(+) for pT2, pT3, and pT4a was 15.3% (27/176), 49.1% (58/118), and 100% (1/1), respectively. Overall, there were 55.61%, 80.61%, and 84.69% of men continent at 3, 6, and 12 months, respectively. However, when limiting the analysis to those who did not receive adjuvant radiotherapy within 12 months following surgery, urinary continence rates were 59.23%, 85.86%, and 90.21% at 3, 6, and 12 months, respectively. Preoperative prostate-specific antigen (PSA) and pathological T stage were identified as significant predictors of positive surgical margins. Conclusions Conclusions: Laparoscopic radical extraperitoneal prostatectomy with bladder neck preservation has been a safe procedure which has resulted in good functional outcome. We observed a relatively high incidence of positive surgical margins which could be attributed to a large number of extracapsular disease cases. PMID:25337159

  6. Is "Warm Arctic, Cold Continent" A Fingerprint Pattern of Climate Change?

    NASA Astrophysics Data System (ADS)

    Hoerling, M. P.; Sun, L.; Perlwitz, J.

    2015-12-01

    Cold winters and cold waves have recently occurred in Europe, central Asia and the Midwest to eastern United States, even as global mean temperatures set record highs and Arctic amplification of surface warming continued. Since 1979, Central Asia winter temperatures have in fact declined. Conjecture has it that more cold extremes over the mid-latitude continents should occur due to global warming and the impacts of Arctic sea ice loss. A Northern Hemisphere temperature signal termed the "Warm Arctic, Cold Continent" pattern has thus been surmised. Here we use a multi-model approach to test the hypothesis that such a pattern is indeed symptomatic of climate change. Diagnosis of a large model ensemble of historical climate simulations shows some individual realizations to yield cooling trends over Central Asia, but importantly the vast majority show warming. The observed cooling has thus likely been a low probability state of internal variability, not a fingerprint of forced climate change. We show that daily temperature variations over continents decline in winter due to global warming, and cold waves become less likely. This is partly related to diminution of Arctic cold air reservoirs due to warming-induced sea ice loss. Nonetheless, we find some evidence and present a physical basis that Arctic sea ice loss alone can induce a winter cooling over Central Asia, though with a magnitude that is appreciably smaller than the overall radiative-forced warming signal. Our results support the argument that recent cooling trends over central Asia, and cold extreme events over the winter continents, have principally resulted from atmospheric internal variability and have been neither a forced response to Arctic seas ice loss nor a symptom of global warming. The paradigm of climate change is thus better expressed as "Warm Arctic, Warm Continent" for the NH winter.

  7. 77 FR 39696 - Atlas Pipeline Mid-Continent WestTex, LLC; Pioneer Natural Resources USA, Inc.; Notice of Intent...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-05

    ... Energy Regulatory Commission Atlas Pipeline Mid-Continent WestTex, LLC; Pioneer Natural Resources USA... by Atlas Pipeline Mid-Continent WestTex, LLC and Pioneer Natural Resources USA, Inc. (Atlas and... provided landowners with a fact sheet prepared by the FERC entitled ``An Interstate Natural Gas Facility...

  8. Anthelmintic resistance in sheep farms: update of the situation in the American continent.

    PubMed

    Torres-Acosta, J F J; Mendoza-de-Gives, P; Aguilar-Caballero, A J; Cuéllar-Ordaz, J A

    2012-09-30

    The present paper reviews the frequency of anthelmintic resistance in sheep farms in different countries of the American continent and describes some aspects that might influence the trend in sheep farms. The situation of anthelmintic resistance in sheep farms has been explored mainly in south of the continent (Argentina, Brazil and Uruguay) where sheep farming is an important industry. In those three countries, as well as in Paraguay, the first comprehensive surveys of anthelmintic resistance were performed among countries in the continent, which showed evidence of high frequency of sheep farms with anthelmintic resistance. Today, it is common to find sheep flocks with multiple-resistant worms. In North and Central America, a similar situation has been reported in sheep farms in the south of the United States of America, parts of Mexico and Costa Rica. On the other hand, other areas of the continent show low frequency of farms with anthelmintic resistance. From many areas no results have been published regarding situation on anthelmintic resistance or, alternatively, published results have received limited dissemination. Although the diagnosis of anthelmintic resistance is important for decision making of helminth management/control at the farm level, this is still an aspiration rather than a reality. For decades, researchers working on anthelmintic resistance in the American continent have expressed the need to change farmers' attitudes towards anthelmintic drugs. A common advice has been to check the anthelmintic drug efficacy regularly and reduce the dependence on these with alternative control measures. In spite of such advice, the challenge to stop/delay the advancement of anthelmintic resistance against the available anthelmintic drugs is still present. The evidence suggests that anthelmintic resistance is a growing phenomenon in the American continent. The situation described might be the tip of the iceberg, as anthelmintic resistance is still largely under

  9. Is there any correlation between continents and elevated temperatures in the subcontinental mantle?

    NASA Astrophysics Data System (ADS)

    Jain, Charitra; Rozel, Antoine; Tackley, Paul

    2015-04-01

    Rolf et al. (EPSL, 2012) and Coltice et al. (Science, 2012) have previously shown that continents exert a first order influence on Earth's mantle flow by affecting convective wavelength and surface heat flow. However, how continents influence the development and location of mantle plumes (upwellings) remains a topic of considerable debate. While Heron and Lowman (GRL, 2010; Tectonophysics, 2011) propose regions where downwelling has ceased (irrespective of overlying plate) as the preferred location for plumes, O'Neill et al. (Gondwana Research, 2009) show an anti-correlation between the average positions of subducting slabs at continental margins, and mantle plumes at continental/oceanic interiors. Continental motion is attributed to the viscous stresses imparted by the convecting mantle and the extent of this motion depends on the heat budget of the mantle. Core-mantle boundary (CMB) heat flux, internal heating from decay of radioactive elements, and mantle cooling contribute to this heat budget. Out of these sources, CMB heat flux is not well defined. However, the recent determination of core's high thermal conductivity requires a CMB heat flow of at least 12 TW (de Koker et al., PNAS 2012; Pozzo et al., Nature 2012; Gomi et al., PEPI 2013). Thus it is necessary to characterize the impact of basal heating on mantle dynamics with continents and self-consistent plate tectonics. By systematically varying parameters like CMB temperature, continental size, mantle heating modes (basal and internal), and Rayleigh number; we model Boussinesq, incompressible, thermo-chemical mantle convection in 2D spherical annulus geometry using StagYY (Tackley, PEPI 2008). We observe correlation between continents and elevated temperatures in the subcontinental mantle irrespective of the variations in basal heating and continental size (except for very small continents). Moreover, we see episodicity between correlation and anti-correlation with increasing Rayleigh number. Furthermore

  10. Relationship of multispectral satellite data to land surface evaporation from the Australian continent

    NASA Technical Reports Server (NTRS)

    Smith, R. C. G.; Choudhury, B. J.

    1990-01-01

    Based on NOAA-9 AVHRR and Nimbus-7 SMMR satellite data, satellite indices of vegetation from the Australian continent are calculated for the period of May 1986 to April 1987. Visible (VIS) and near infrared (NIR) reflectances and the normalized difference (ND) vegetation index are calculated from the AVHRR sensor. The microwave polarization difference (PD) is also calculated as the difference between the vertically and horizontally polarized brightness temperatures at 37 GHz. ND, PD, VIS, and NIR indices were plotted against rainfall and water balance estimates of evaporation. It is concluded that direct satellite monitoring of annual evaporation across the Australian continent using PD or VIS satellite indices of vegetation biomass appears possible for areas with evaporation less than 600 mm/y and that use of the ND relationship at continental scale may underpredict monthly evaporation of forests relative to agriculture.

  11. Indiana pouch continent urinary reservoir in patients with previous pelvic irradiation

    SciTech Connect

    Mannel, R.S.; Braly, P.S.; Buller, R.E. )

    1990-05-01

    Little information exists on the use of continent urinary reservoirs in patients with previous pelvic irradiation. We report the use of the Indiana pouch urinary reservoir in ten women with a history of pelvic irradiation for cervical cancer, of whom eight underwent a total pelvic exenteration for recurrent pelvic tumor and two had diversion for radiation-induced vesicovaginal fistula. All ten women achieved daytime continence, with a median time between catheterizations of 4.5 hours and a median pouch capacity of 500 mL. There was no evidence of leakage from the reservoir or significant ureteral reflux or obstruction on postoperative radiographic evaluation. No patient has required reoperation or had significant postoperative complications with the technique described.

  12. A staff management system for maintaining improvements in continence with elderly nursing home residents.

    PubMed Central

    Burgio, L D; Engel, B T; Hawkins, A; McCormick, K; Scheve, A; Jones, L T

    1990-01-01

    We developed a staff management system for maintaining treatment gains achieved on a specialized continence unit located in a geriatric nursing home. Geriatric assistants learned to use a prompted voiding procedure to maintain improved dryness for 4 elderly residents. The staff management system included self-monitoring and recording of prompted voiding activities and supervisory monitoring and feedback based on group performance of these activities. Results show that the system was effective in maintaining prompted voiding activities with corresponding maintenance of improved patient continence. However, a gradual decline in staff performance was noted 4 to 5 months after the initiation of the system. During a subsequent phase of the study, provision of individual feedback restored staff performance to previous levels. Results are discussed in relation to the practicality of prompted voiding interventions in nursing home environments and the applicability of staff management systems in this setting. PMID:2335482

  13. Ophiolites in ocean-continent transitions: From the Steinmann Trinity to sea-floor spreading

    NASA Astrophysics Data System (ADS)

    Bernoulli, Daniel; Jenkyns, Hugh C.

    2009-05-01

    Before the theory of plate tectonics took hold, there was no coherent model for ocean-continent transitions that included both extant continental margins and fragmentary ancient examples preserved in orogenic belts. Indeed, during the early 1900, two strands of thought developed, one relying on the antiquity and permanence of continents and oceans, advocated by the mainstream of the scientific community and one following mobilist concepts derived from Wegener's hypothesis (1915) of continental drift. As an illustration of the prevailing North-American view, the different composition and thickness of continental and oceanic crust and the resulting isostatic response showed "how improbable it would be to suppose that a continent could founder or go to oceanic depth or that ocean floor at ± 3000 fathoms could ever have been a stable land area since the birth of the oceans" [H.H. Hess, Trans. R. Soc. London, A 222 (1954) 341-348]. Because of the perceived permanence of oceans and continents, mountain chains were thought to originate from narrow, elongated, unstable belts, the geosynclines, circling the continents or following "zones of crustal weakness" within them, from which geanticlines and finally mountain belts would develop. This teleological concept, whereby a geosyncline would inevitably evolve into a mountain chain, dominated geological interpretations of orogenic belts for several decades in the mid-twentieth century. However, the concept of permanence of oceans and continents and the concept of the geosyncline had already met with the critiques of Suess and others. As early as 1905, Steinmann considered the association of peridotite, "diabase" (basalt/dolerite) and radiolarite (a typical ocean-continent transition assemblage), present in the Alps and Apennines, as characteristic of the deep-ocean floor and Bailey (1936) placed Steinmann's interpretation into the context of continental drift and orogeny. Indeed, in both authors' writings, the concept of

  14. Image of the Moho across the continent-ocean transition, US east coast

    SciTech Connect

    Holbrook, W.S.; Purdy, G.M. ); Reiter, E.C.; Toksoez, M.N. )

    1992-03-01

    Strong wide-angle reflections from the Moho were recorded by ocean-bottom seismic instruments during the 1988 Carolina Trough multichannel seismic experiment, in an area where the Moho is difficult to detect with vertical-incidence seismic data. Prestack depth migration of these reflections has enabled the construction of a seismic image of the Moho across the continent-ocean transition of a sedimented passive margin. The Moho rises across the margin at a slope of 10{degree}-12{degree}, from a depth of about 33 km beneath the continental shelf to 20 km beneath the outer rise. This zone of crustal thinning defines a distinct, 60-70-km-wide continent-ocean transition zone. The authors interpret the Moho in the Carolina Trough as a Jurassic feature, formed by magmatic intrusion and underplating during the rifting of Pangea.

  15. Continent appendicocolostomy: a variation of the Mitrofanoff principle in pediatric urinary tract reconstruction.

    PubMed

    Elder, J S

    1992-07-01

    There are numerous options for continent urinary reconstruction in children. If the appendix is available and the bladder capacity is satisfactory, a Mitrofanoff procedure may be performed using the appendix as a catheterizable tube implanted into the bladder. However, in many patients the bladder is absent or too small for this type of reconstruction. An alternative technique, termed appendicocolostomy, is to implant the appendix under the tenia of a detubularized patch of cecum or sigmoid colon, which becomes part of a continent neobladder or is attached to the bladder itself. This procedure has been used in 12 children and 1 adult undergoing continent reconstruction. Urological diseases included bladder exstrophy (10 patients) and a neuropathic bladder (3). Two patients underwent undiversion of a sigmoid conduit, while in 7 of the remaining patients the bladder was included in the reservoir. In 1 patient histological examination of the tip of the appendix revealed an incidental invasive carcinoid tumor necessitating appendectomy and revision of the reconstruction. Otherwise, no complications have occurred. Three adults were scheduled for this procedure but the appendix was diseased and an alternative form of diversion was necessary. Followup ranged from 2 months to 4 years. All patients are totally dry with a capacity of 300 to 750 cc (mean 475 cc). The appendicocolostomy is a superior form of conduit reconstruction that should be considered when the appendix is available during continent reconstruction. However, in adults the appendix may be fibrotic, precluding its use. Because most boys with exstrophy and a small bladder capacity requiring augmentation cystoplasty must perform intermittent catheterization, attachment of the appendix to the reservoir is an alternative that allows for easier and less painful intermittent catheterization than catheterization of the reconstructed epispadiac penis. PMID:1613848

  16. Cold cratonic roots and thermal blankets: How continents affect mantle convection

    USGS Publications Warehouse

    Trubitsyn, V.P.; Mooney, W.D.; Abbott, D.H.

    2003-01-01

    Two-dimensional convection models with moving continents show that continents profoundly affect the pattern of mantle convection. If the continents are wider than the wavelength of the convection cells (???3000 km, the thickness of the mantle), they cause neighboring deep mantle thermal upwellings to coalesce into a single focused upwelling. This focused upwelling zone will have a potential temperature anomaly of about 200??C, much higher than the 100??C temperature anomaly of upwelling zones generated beneath typical oceanic lithosphere. Extensive high-temperature melts (including flood basalts and late potassic granites) will be produced, and the excess temperature anomaly will induce continental uplift (as revealed in sea level changes) and the eventual breakup of the supercontinent. The mantle thermal anomaly will persist for several hundred million years after such a breakup. In contrast, small continental blocks (<1000 km diameter) do not induce focused mantle upwelling zones. Instead, small continental blocks are dragged to mantle downwelling zones, where they spend most of their time, and will migrate laterally with the downwelling. As a result of sitting over relatively cold mantle (downwellings), small continental blocks are favored to keep their cratonic roots. This may explain the long-term survival of small cratonic blocks (e.g., the Yilgarn and Pilbara cratons of western Australia, and the West African craton). The optimum size for long-term stability of a continental block is <3000 km. These results show that continents profoundly affect the pattern of mantle convection. These effects are illustrated in terms of the timing and history of supercontinent breakup, the production of high-temperature melts, and sea level changes. Such two-dimensional calculations can be further refined and tested by three-dimensional numerical simulations of mantle convection with moving continental and oceanic plates.

  17. Bladder agenesis and incomplete kidney duplication: Ileal reservoir with continent diversion as definitive treatment

    PubMed Central

    Pacheco-Mendoza, Byron Alexis; González-Ledón, Fernando J.; Díaz-Pardo, Mario; Soto-Blanquel, Juan L.; Castelán-Martínez, Osvaldo Daniel

    2015-01-01

    Bladder agenesis is an extremely rare entity. A 12-year-old female patient presented with urinary incontinence, recurrent urinary tract infections, visible vaginal introitus and urethra, and two holes at the vulvar vestibule. An investigation revealed bladder agenesis. Surgery confirmed the absence of bladder, and ileal reservoir in omega (Ω) was performed with continent diversion. At the 30-month follow-up, there was no complication in clean intermittent catheterization. PMID:25844102

  18. Uppermost mantle structure of the Australian continent from Pn traveltime tomography

    NASA Astrophysics Data System (ADS)

    Sun, Weijia; Kennett, B. L. N.

    2016-03-01

    Past studies of the seismic structure of the Australian continent have dominantly exploited surface wave tomography for the mantle, with seismic refraction, receiver functions, and ambient noise used for crustal structure. The 3-D structure has been summarized in the Australian Seismological Reference Model (AuSREM), for which the zone immediately below the crust is the least well characterized. Pn traveltime tomography provides a way of improving structural information on the uppermost mantle across the continent. We have exploited waveforms from larger events across Australia recorded at both permanent and portable stations since 1993, supplemented by bulletin arrival times. To compensate for the large velocity contrasts, with much faster mantle wave speeds in the center and west, all events were relocated using the AuSREM model. After relocation, consistent patterns of traveltime residuals are obtained. We extract Pn as the first arrival in the distance range 1.8° to 15°. We use the FMTOMO approach to invert the travel-time residuals to generate a P wave speed structure with a resolution of 3°×3°. There is strong heterogeneity in Pn wave speed in the uppermost mantle across the continent. The fastest Pn wave speed of 8.36 km/s beneath the Precambrian cratons of western and central Australia is 3.99% faster than the global ak135 model, and the slowest Pn wave speed 7.66 km/s on the eastern margin is 4.74% slower. The slowest velocities in the uppermost mantle are found along the eastern margin of the Australian continent beneath the Phanerozoic orogenic belts, with links to Neogene volcanism.

  19. Fault Interaction and Earthquake Migration in Mid-Continents: Insights from Numerical Modeling

    NASA Astrophysics Data System (ADS)

    Liu, M.; Lu, Y.; Chen, L.; Luo, G.; Wang, H.

    2011-12-01

    Historic records in North China and other mid-continents show large earthquakes migrating among widespread fault systems. Mechanical coupling of these faults is indicated by complimentary seismic moment release on these faults. In a conceptual model (Liu et al., 2011, Lithosphere), the long-distance fault interaction and earthquake migration are explained as the consequences of regional stress readjustment among a system of intraplate faults that collectively accommodates tectonic loading at the plate boundaries. In such a system, failure of one fault (a large earthquake) can cause stress shifting on all other faults. Here we report preliminary results of numerical investigations of such long-distance fault interaction in mid-continents. In a set of elastic models, we have a model crust with internal faults loaded from the boundaries, and calculate the stress distribution on the faults when the system reaches equilibrium. We compare the results with those of a new model that has one or more of the faults weakened (ruptured). The results show that failure of one fault can cause up to a few MPa of stress changes on other faults over a large distance; the magnitude of the stress change and the radius of the impacted area are much greater than those of the static Coulomb stress changes associated with dislocation on the fault plane. In time-dependent viscoelasto-plastic models, we found that variations of seismicity on one fault can significantly affect the loading rates on other faults that share the same tectonic loading. Similar fault interactions are also found in complex plate boundary fault systems, such as between the San Andreas Fault and the San Jacinto Fault in southern California. The spatially migrating earthquakes resulting from the long-distance fault interactions in mid-continents can cause different spatial patterns of seismicity when observed through different time-windows. These results have important implications for assessing earthquake hazards in

  20. Continence outcomes following robotic radical prostatectomy: Our experience from 150 consecutive patients

    PubMed Central

    Gupta, Narmada P.; Yadav, Rajiv; Akpo, Emmanuel E.

    2014-01-01

    Introduction: Urinary continence is an important outcome parameter after robot assisted radical prostatectomy (RARP). We evaluated the continence outcomes following RARP using a double-layered urethrovesical reconstruction. Materials and Methods: One hundred fifty consecutive patients undergoing RARP and double-layered urethrovesical reconstruction were prospectively studied for preoperative, intraoperative and post operative parameters. Key points followed during surgery were: Minimal dissection of sphincteric complex, preservation of puboprostatic ligament, selective ligation of deep venous complex and both posterior and anterior reconstruction using the Von Velthoven stitch. Intraoperative bladder fill test was done at the end of anastomosis to rule out urine leak. Check cystogram was done prior to catheter removal in the outpatient department. Patients were subsequently followed at regular intervals regarding the status of urinary continence. All patients irrespective of adjuvant therapy were included in the analysis. Results: The mean age was 64 years (standard deviation ± 6.88), and mean serum PSA was 20.2 ng/ml. The mean BMI was 25.6 (SD: ±3.84). The mean prostate weight was 44.09 gm (range 18-103 gm, SD: ±15.59). Median days to catheter removal after surgery was 7 (range 4-14 days) days. Cystographically determined urinary leaks were seen in two patients. Urine leak was managed by delaying catheter removal for 1 week. Minimum 6 month follow up was available in 126 patients. ‘No pad’ status at 1 week, 1 month, 3 months, 6 months and 1 year was 15.1%, 54.9%, 78%, 90.5% and 94.1%, respectively. Conclusion: Excellent continence outcomes are observed in patients undergoing double-layered urethrovesical reconstruction. PMID:25378816

  1. A study on the birth and globalization of sports originated from each continent

    PubMed Central

    Lee, Byung Jin; Kim, Tae Young

    2016-01-01

    The purpose of this research is to see how continent specific sports rose to its modern-day status through globalization. This research focuses on the historical background of how England’s football, America’s national pastime, baseball, Japan’s Judo, and Korea’s Taekwondo developed into sports in addition to the reasoning behind its globalization. Promoted by England and the rest of the European continent, Soccer is considered to be one of the world’s most popular sports and has served its function as a form of cultural imperialism. It has also advanced alongside commerce, missionary work and other types of cultural clashes. In America, baseball was used to integrate its multicultural society and developed so that the team captain leads the rest of his team. The sports of Oriental countries were reborn through modernization that was influenced by the modern rationality, education etc. of its Western counterparts. Judo and Taekwondo were introduced globally through the Olympic Games. As mentioned above the birth of sporting events has a close connection to a nation’s cultural background and globalization has taken different forms depending on which continent it originated from. PMID:26933653

  2. Hypothesis That Urethral Bulb (Corpus Spongiosum) Plays an Active Role in Male Urinary Continence

    PubMed Central

    Rehder, Peter; Staudacher, Nina M.; Schachtner, Joerg; Berger, Maria E.; Schillfahrt, Florian; Hauser, Verena; Mueller, Raphael; Skradski, Viktor; Horninger, Wolfgang; Glodny, Bernhard

    2016-01-01

    The proximal urethral bulb in men is enlarged, surrounds the bulbous urethra, and extends dorsally towards the perineum. During intercourse engorgement takes place due to increased blood flow through the corpus spongiosum. Antegrade ejaculation is facilitated by contraction of the bulbospongiosus muscles during climax. Micturition during sexual stimulation is functionally inhibited. Supporting the bulb may indirectly facilitate continence in a certain subset of patients with postprostatectomy incontinence. During physical activity with increased abdominal pressure, reflex contraction of the pelvic floor muscles as well as the bulbospongiosus muscles occurs to support sphincter function and limit urinary incontinence. Operations to the prostate may weaken urinary sphincter function. It is hypothesized that the distal urinary sphincter may be supported indirectly by placing a hammock underneath the urethral bulb. During moments of physical stress the “cushion” of blood within the supported corpus spongiosum helps to increase the zone of coaptation within the sphincteric (membranous) urethra. This may lead to urinary continence in patients treated by a transobturator repositioning sling in patients with postprostatectomy incontinence. This paper describes the possible role of the urethral bulb in male urinary continence, including its function after retroluminal sling placement (AdVance, AdVance XP® Male Sling System, Minnetonka, USA). PMID:27022393

  3. Two-step rise of atmospheric oxygen linked to the growth of continents

    NASA Astrophysics Data System (ADS)

    Lee, Cin-Ty A.; Yeung, Laurence Y.; McKenzie, N. Ryan; Yokoyama, Yusuke; Ozaki, Kazumi; Lenardic, Adrian

    2016-06-01

    Earth owes its oxygenated atmosphere to its unique claim on life, but how the atmosphere evolved from an initially oxygen-free state remains unresolved. The rise of atmospheric oxygen occurred in two stages: approximately 2.5 to 2.0 billion years ago during the Great Oxidation Event and roughly 2 billion years later during the Neoproterozoic Oxygenation Event. We propose that the formation of continents about 2.7 to 2.5 billion years ago, perhaps due to the initiation of plate tectonics, may have led to oxygenation by the following mechanisms. In the first stage, the change in composition of Earth's crust from iron- and magnesium-rich mafic rocks to feldspar- and quartz-rich felsic rocks could have caused a decrease in the oxidative efficiency of the Earth's surface, allowing atmospheric O2 to rise. Over the next billion years, as carbon steadily accumulated on the continents, metamorphic and magmatic reactions within this growing continental carbon reservoir facilitated a gradual increase in the total long-term input of CO2 to the ocean-atmosphere system. Given that O2 is produced during organic carbon burial, the increased CO2 input may have triggered a second rise in O2. A two-step rise in atmospheric O2 may therefore be a natural consequence of plate tectonics, continent formation and the growth of a crustal carbon reservoir.

  4. A study on the birth and globalization of sports originated from each continent.

    PubMed

    Lee, Byung Jin; Kim, Tae Young

    2016-02-01

    The purpose of this research is to see how continent specific sports rose to its modern-day status through globalization. This research focuses on the historical background of how England's football, America's national pastime, baseball, Japan's Judo, and Korea's Taekwondo developed into sports in addition to the reasoning behind its globalization. Promoted by England and the rest of the European continent, Soccer is considered to be one of the world's most popular sports and has served its function as a form of cultural imperialism. It has also advanced alongside commerce, missionary work and other types of cultural clashes. In America, baseball was used to integrate its multicultural society and developed so that the team captain leads the rest of his team. The sports of Oriental countries were reborn through modernization that was influenced by the modern rationality, education etc. of its Western counterparts. Judo and Taekwondo were introduced globally through the Olympic Games. As mentioned above the birth of sporting events has a close connection to a nation's cultural background and globalization has taken different forms depending on which continent it originated from. PMID:26933653

  5. Percutaneous Imaging-Guided Access for the Treatment of Calculi in Continent Urinary Reservoirs

    SciTech Connect

    Davis, Winston Brooks; Trerotola, Scott O.; Johnson, Matthew S.; Patel, Nilesh H.; Namyslowski, Jan; Stecker, Michael S.; McLennan, Gordon; Shah, Himanshu; Bihrle, Richard; Foster, Richard

    2002-03-15

    Purpose: To describe our long-term experience with percutaneous access to continent urinary reservoirs for calculus removal. Patients and Methods: A retrospective study of 13 procedures in 10 patients was performed. In 2 of the 13 procedures, access and calculus removal was performed in a single session. In the other 11 procedures, initial access was obtained using ultrasonography,fluoroscopy, and/or computed tomography. The patients then returned ata later date for a second step where the access was dilated and the calculi were removed. Results: Access was achieved successfully in all cases with no complications. At mean follow-up time of 13.6 months (range 1-94 months) one patient had died of complications unrelated to her continent urinary reservoir. Another patient had been placed on suppressive antibiotics for recurrent calculi. The remaining patients were stone free and without late complication. Conclusions: Percutaneous removal of reservoir calculi can be performed safely, avoiding potential injury to the continence valve mechanism by a direct cystoscopic approach. We propose a two-stage procedure using CT guidance for initial access as the preferred technique.

  6. Seasonal Variability of Rainfall Over Indonesia Maritime Continent Based on Trmm pr Observations

    NASA Astrophysics Data System (ADS)

    Yulihastin, Erma; Kodama, Yasu-Masa

    Temporal and spatial distribution of near surface rain and three types of rainfall namely shallow rain, convective rain, and stratiform rain over Indonesia Maritime Continent (90E-150E, 15S-15N) was investigated using Tropical Rainfall Measuring Mission Precipitation Radar in a 10-years dataset (1998-2007). This research also using least square method to confirm distribution of annual and semiannual oscillation of rainfall over Indonesia Maritime Continent (IMC). Climatology rainfall of shallow, stratiform, and convective have agreement to seasonal variability of rainfall over IMC that influenced by monsoon which was rainfall became increased from November to April and reached peak value in January. Conversely, rainfall decreased from May to October and reached lowest value in July. The distribution of shallow rain showed the unique seasonal rainfall for local region namely Sulawesi, Maluku, and closely region. Seasonal of shallow rain in those regions approve to local type of rainfall which was reach peak value in July and August. This rainfall type was opposite to equator rainfall and monsoon rainfall in the most of IMC regions which are dry season occured in the same period. Shallow rain may contributed to local rainfall type over IMC. It might be drived by increasing low level moisture and strongly of subsidence flow in boundary layer which is also influenced by enhancement of Sea Surface Temperature in Malacca Strait at the same period. Keyword: Indonesia Maritime Continent, Tropical Rainfall Measuring Mission, Seasonal Vari-ability

  7. Parallel Evolution of Copy-Number Variation across Continents in Drosophila melanogaster.

    PubMed

    Schrider, Daniel R; Hahn, Matthew W; Begun, David J

    2016-05-01

    Genetic differentiation across populations that is maintained in the presence of gene flow is a hallmark of spatially varying selection. In Drosophila melanogaster, the latitudinal clines across the eastern coasts of Australia and North America appear to be examples of this type of selection, with recent studies showing that a substantial portion of the D. melanogaster genome exhibits allele frequency differentiation with respect to latitude on both continents. As of yet there has been no genome-wide examination of differentiated copy-number variants (CNVs) in these geographic regions, despite their potential importance for phenotypic variation in Drosophila and other taxa. Here, we present an analysis of geographic variation in CNVs in D. melanogaster. We also present the first genomic analysis of geographic variation for copy-number variation in the sister species, D. simulans, in order to investigate patterns of parallel evolution in these close relatives. In D. melanogaster we find hundreds of CNVs, many of which show parallel patterns of geographic variation on both continents, lending support to the idea that they are influenced by spatially varying selection. These findings support the idea that polymorphic CNVs contribute to local adaptation in D. melanogaster In contrast, we find very few CNVs in D. simulans that are geographically differentiated in parallel on both continents, consistent with earlier work suggesting that clinal patterns are weaker in this species. PMID:26809315

  8. Hypothesis That Urethral Bulb (Corpus Spongiosum) Plays an Active Role in Male Urinary Continence.

    PubMed

    Rehder, Peter; Staudacher, Nina M; Schachtner, Joerg; Berger, Maria E; Schillfahrt, Florian; Hauser, Verena; Mueller, Raphael; Skradski, Viktor; Horninger, Wolfgang; Glodny, Bernhard

    2016-01-01

    The proximal urethral bulb in men is enlarged, surrounds the bulbous urethra, and extends dorsally towards the perineum. During intercourse engorgement takes place due to increased blood flow through the corpus spongiosum. Antegrade ejaculation is facilitated by contraction of the bulbospongiosus muscles during climax. Micturition during sexual stimulation is functionally inhibited. Supporting the bulb may indirectly facilitate continence in a certain subset of patients with postprostatectomy incontinence. During physical activity with increased abdominal pressure, reflex contraction of the pelvic floor muscles as well as the bulbospongiosus muscles occurs to support sphincter function and limit urinary incontinence. Operations to the prostate may weaken urinary sphincter function. It is hypothesized that the distal urinary sphincter may be supported indirectly by placing a hammock underneath the urethral bulb. During moments of physical stress the "cushion" of blood within the supported corpus spongiosum helps to increase the zone of coaptation within the sphincteric (membranous) urethra. This may lead to urinary continence in patients treated by a transobturator repositioning sling in patients with postprostatectomy incontinence. This paper describes the possible role of the urethral bulb in male urinary continence, including its function after retroluminal sling placement (AdVance, AdVance XP® Male Sling System, Minnetonka, USA). PMID:27022393

  9. Longitudinal Study of Intestinal Symptoms and Fecal Continence in Patients With Conformal Radiotherapy for Prostate Cancer

    SciTech Connect

    Geinitz, Hans; Thamm, Reinhard; Keller, Monika; Astner, Sabrina T.; Heinrich, Christine; Scholz, Christian; Pehl, Christian; Kerndl, Simone; Prause, Nina; Busch, Raymonde; Molls, Michael; Zimmermann, Frank B.

    2011-04-01

    Purpose: To prospectively assess the intestinal symptoms and fecal continence in patients who had undergone conformal radiotherapy (CRT) for prostate cancer. Methods and Materials: A total of 78 men who had undergone definitive CRT for prostate cancer were evaluated. The patients were assessed before, during (treatment Weeks 4 and 6), and 2, 12, and 24 months after CRT completion. The intestinal symptoms and fecal continence were evaluated with comprehensive standardized questionnaires. Results: The intestinal symptoms were mostly intermittent, with only a small minority of patients affected daily. Defecation pain, fecal urge, and rectal mucous discharge increased significantly during therapy. Defecation pain and rectal mucous discharge had returned to baseline levels within 8 weeks and 1 year after CRT, respectively. However, fecal urge remained significantly elevated for {<=}1 year and then returned toward the pretreatment values. The prevalence of rectal bleeding was significantly elevated 2 years after CRT. Fecal continence deteriorated during CRT and remained impaired at 1 year after treatment. Incontinence was mostly minor, occurring less than once per week and predominantly affecting incontinence for gas. Conclusion: Intestinal symptoms and fecal incontinence increased during prostate CRT. Except for rectal bleeding, the intestinal symptoms, including fecal incontinence, returned to baseline levels within 1-2 years after CRT. Thus, the rate of long-term late radiation-related intestinal toxicity was low.

  10. Integrated Mid-Continent Carbon Capture, Sequestration & Enhanced Oil Recovery Project

    SciTech Connect

    Brian McPherson

    2010-08-31

    A consortium of research partners led by the Southwest Regional Partnership on Carbon Sequestration and industry partners, including CAP CO2 LLC, Blue Source LLC, Coffeyville Resources, Nitrogen Fertilizers LLC, Ash Grove Cement Company, Kansas Ethanol LLC, Headwaters Clean Carbon Services, Black & Veatch, and Schlumberger Carbon Services, conducted a feasibility study of a large-scale CCS commercialization project that included large-scale CO{sub 2} sources. The overall objective of this project, entitled the 'Integrated Mid-Continent Carbon Capture, Sequestration and Enhanced Oil Recovery Project' was to design an integrated system of US mid-continent industrial CO{sub 2} sources with CO{sub 2} capture, and geologic sequestration in deep saline formations and in oil field reservoirs with concomitant EOR. Findings of this project suggest that deep saline sequestration in the mid-continent region is not feasible without major financial incentives, such as tax credits or otherwise, that do not exist at this time. However, results of the analysis suggest that enhanced oil recovery with carbon sequestration is indeed feasible and practical for specific types of geologic settings in the Midwestern U.S.

  11. Seismotectonic features of the African plate: the possible dislocation of a continent

    NASA Astrophysics Data System (ADS)

    Meghraoui, Mustapha

    2014-05-01

    The African continent is made of seismically active structures with active deformation in between main substratum shields considered as stable continental interiors. Seismically active regions are primarily located along rift zones, thrust and fold mountain belts, transform faults and volcanic fields. The active tectonic structures generated large and destructive earthquakes in the past with significant damage and economic losses in Africa. Although some regions of the continent show a low-level of seismic activity, several large earthquakes (with M > 7) have occurred in the past. The presence of major active faults that generate destructive earthquakes is among the most important geological and geophysical hazards for the continent. National and International scientific projects dealing with the seismic hazards assessment are increasing in seismically active regions in Africa. The UNESCO-SIDA/IGCP (Project 601 http://eost.u-strasbg.fr/~igcp601/) support the preparation and implementation of the "Seismotectonic Map of Africa". Therefore, new seismotectonic data with the regional analysis of earthquake hazards became necessary as a basis for a mitigation of the earthquake damage. A database in historical and instrumental seismicity, active tectonics, stress tensor distribution, earthquake geology and paleoseismology, active deformation, earthquake geodesy (GPS) and gravity, crustal structure studies, magnetic and structural segmentation, volcanic fields, collision tectonics and rifting processes is prepared to constrain the geodynamic evolution of the continent. Taking into account the geological, tectonic and geophysical characteristics, we define six seismotectonic provinces that characterize the crustal deformation. With the previously identified Somalia tectonic block, the seismotectonic and geophysical framework of the continent reveal the existence of the Cameroon volcanic line, the South African tectonic block with transform faulting and Cape folding system

  12. Atmospheric dry deposition of trace elements at a site on Asian-continent side of Japan

    NASA Astrophysics Data System (ADS)

    Sakata, Masahiro; Asakura, Kazuo

    2011-02-01

    The sources of dry-deposited trace elements (As, Cd, Cr, Cu, Mn, Ni, Pb, Sb and V) and the factors controlling their dry deposition fluxes were investigated on the basis of two-year observations (April 2004-March 2006) at a site on the Asian-continent side of Japan, which has been strongly affected by air pollutants from the Asian continent. Dry deposition sampling was conducted using a water surface sampler connected to a wet-only precipitation sampler. The dry deposition of As, Cd, Pb and Sb showed a small contribution to atmospheric deposition (0.25-0.44 as ratios of annual dry/wet deposition fluxes). Moreover, the dry deposition fluxes of those elements increased negligibly during the period when their atmospheric particulate matter (PM) concentrations increased owing to transport from the Asian continent. Thus, the dry deposition of As, Cd, Pb and Sb from the Asian continent was not significant, because their overall dry deposition velocities are relatively low (mostly <1 cm s -1). Conversely, the annual dry deposition fluxes of Cr, Cu and Ni exceeded their annual wet deposition fluxes (2.5-12.4 as ratios of annual dry/wet deposition fluxes). Those overall dry deposition velocities were much higher (3.2-9.7 cm s -1), and the crustal enrichment factors (EFs) frequently exceeded ten. These results suggest that the dry deposition of Cr, Cu and Ni is dominated by considerably coarse particles from local anthropogenic sources. For Mn and V, the dry and wet depositions contributed almost equally to the annual deposition fluxes. Their monthly dry deposition fluxes correlated significantly with that of Al ( P < 0.001), and the EFs were close to unity, suggesting a large contribution of background soil to their dry deposition. The dry deposition fluxes of all the trace elements were dependent not on their atmospheric PM concentrations but on their overall dry deposition velocities. The particle size distributions of the elements in the atmosphere are likely the most

  13. Continent cutaneous diversion and external genitalia reconstruction in a child with severe variety urogenital sinus and ambiguous genitalia.

    PubMed

    Khemchandani, Sajni I

    2015-01-01

    The diagnosis and management of a child with ambiguous genitalia and severe variety of urogenital sinus with a high vesico-vaginal confluence is challenging. This 4-year-old female child had solitary right kidney with ectopic ureter opening in high variety of urogenital sinus with hypo-plastic urinary bladder and incontinence. We describe genitourinary reconstruction with complete functional rehabilitation in this child. This complex problem was managed with continent urinary diversion with Penn pouch and refashioning of external genitalia, rendering continence and near normal female external genitalia. The child and parents are happy with continence and aesthetically normal external genitalia. PMID:25829673

  14. Monitoring of Internet Forums to Evaluate Reactions to the Introduction of Reformulated OxyContin to Deter Abuse

    PubMed Central

    Coplan, Paul M; Black, Ryan A; Weber, Sarah E; Chilcoat, Howard D; Butler, Stephen F

    2014-01-01

    Background Reformulating opioid analgesics to deter abuse is one approach toward improving their benefit-risk balance. To assess sentiment and attempts to defeat these products among difficult-to-reach populations of prescription drug abusers, evaluation of posts on Internet forums regarding reformulated products may be useful. A reformulated version of OxyContin (extended-release oxycodone) with physicochemical properties to deter abuse presented an opportunity to evaluate posts about the reformulation in online discussions. Objective The objective of this study was to use messages on Internet forums to evaluate reactions to the introduction of reformulated OxyContin and to identify methods aimed to defeat the abuse-deterrent properties of the product. Methods Posts collected from 7 forums between January 1, 2008 and September 30, 2013 were evaluated before and after the introduction of reformulated OxyContin on August 9, 2010. A quantitative evaluation of discussion levels across the study period and a qualitative coding of post content for OxyContin and 2 comparators for the 26 month period before and after OxyContin reformulation were conducted. Product endorsement was estimated for each product before and after reformulation as the ratio of endorsing-to-discouraging posts (ERo). Post-to-preintroduction period changes in ERos (ie, ratio of ERos) for each product were also calculated. Additionally, post content related to recipes for defeating reformulated OxyContin were evaluated from August 9, 2010 through September 2013. Results Over the study period, 45,936 posts related to OxyContin, 18,685 to Vicodin (hydrocodone), and 23,863 to Dilaudid (hydromorphone) were identified. The proportion of OxyContin-related posts fluctuated between 6.35 and 8.25 posts per 1000 posts before the reformulation, increased to 10.76 in Q3 2010 when reformulated OxyContin was introduced, and decreased from 9.14 in Q4 2010 to 3.46 in Q3 2013 in the period following the reformulation

  15. Mesohabitat-specific Macroinvertebrate Assemblage Responses to Water Quality Variation in Mid-continent (North America) Great Rivers

    EPA Science Inventory

    We compared the responsiveness of macroinvertebrate assemblages to water quality stressors (ions, nutrients, dissolved metals and suspended sediment) in two mesohabitats within the main-channel macrohabitat of three mid-continent North American rivers, the Upper Mississippi, Miss...

  16. Refertilization-driven destabilization of subcontinental mantle and the importance of initial lithospheric thickness for the fate of continents

    NASA Astrophysics Data System (ADS)

    Zheng, J. P.; Lee, C.-T. A.; Lu, J. G.; Zhao, J. H.; Wu, Y. B.; Xia, B.; Li, X. Y.; Zhang, J. F.; Liu, Y. S.

    2015-01-01

    Continents are underlain by thick, cold thermal boundary layers. Thermal contraction should render these boundary layers negatively buoyant and unstable; this is why old, cold oceanic lithospheres subduct. However, the ancient lithospheric roots of many continents appear to have existed for billions of years. In the common view, this preservation is due to the fact that the thermal boundary layers are compositionally distinct from the ambient mantle in that they are highly melt-depleted and dehydrated; the former provides positive buoyancy and the latter provides strength. Here, we show using mantle xenoliths that the Precambrian South China Block originally was underlain by highly depleted mantle, but has been refertilized via silicate melts generated from the asthenosphere. It is now more fertile than the ambient convecting mantle and is intrinsically denser by more than 1.5%. Achieving sufficient melt generation for refertilization is only possible if the lithosphere is thin enough to provide "headspace" for decompression melting. Thus, continental boundary layers thinner than the maximum depth of melting should experience refertilization, whereas thicker continents would altogether suppress melting and hence the potential for refertilization. We propose that refertilization, once initiated, will destabilize the base of the continent; this in turn will increase the amount of "headspace" and promote further refertilization, resulting in a positive feedback that could culminate in lithospheric destruction. By contrast, continents that are thick enough may not experience significant refertilization. This suggests that initial lithospheric thickness, as well as lithospheric composition, may be important for defining the fate of continents.

  17. A satellite-based perspective of convective systems over the Maritime Continent

    NASA Astrophysics Data System (ADS)

    Rowe, A.; Houze, R.; Virts, K.; Zuluaga, M. D.

    2014-12-01

    Data from TRMM, the A-Train satellites, and the Worldwide Lightning Location Network (WWLLN) have been used to study extreme weather throughout low latitudes, from deep convection over the Himalayas to oceanic mesoscale systems associated with the MJO. This study presents a more in-depth examination of convection over the Maritime Continent (Indonesia and Malaysia). During November to February, this area is the rainiest regional climate on Earth, thus constituting one of the atmosphere's primary heat sources. On multiple temporal and spatial scales, it is a complex region with clouds and precipitation having both oceanic and orographic influence. The November-February season encompasses both the eastward propagation of the MJO through this region and rainfall associated with the Asian-Australian monsoon. More specifically, the precipitation in this region is strongly modulated by MJO phases, pulsations of the monsoon, and the powerful diurnal effects of the islands and ocean. Through a feature-based analysis of convective and stratiform components of storms, the evolution of precipitating clouds in this region will be described using data from the November-February time period over multiple years. This analysis leads to an increased understanding of the characteristics of convection associated with the intraseasonal and diurnal variability during these months over the Maritime Continent. Previous work using A-Train data noted the prevalence of smaller separated MCSs over the region during the locally active phase of the MJO, and WWLLN data have shown a peak in lightning density as convection becomes deeper and more numerous leading up to this active period. By applying the analysis of the TRMM data in addition to the A-Train and WWLLN datasets, the relative roles of convective and stratiform components of MCSs to the behavior of convection can be determined during the MJO and monsoonal maxima of rainfall over the Maritime Continent.

  18. The Emerging Legacy of USArray: New Views of the Architecture of the North American Continent

    NASA Astrophysics Data System (ADS)

    Ritzwoller, M. H.

    2013-12-01

    In the decade that preceded the new millennium, seismologists on several continents dared to think big: envisioning, designing, and then building seismic arrays of unprecedented quality, resolution, and scale. In the US, their vision became USArray: thousands of broadband seismometers spanning the continent, professionally deployed, superbly maintained, with data ready in realtime quite literally at one's fingertips. For many young (and not so young) seismologists the building of USArray, particularly the Transportable Array, marks the crucial event of their scientific careers. An important part of the legacy of USArray will be an improved understanding of the architecture of the North American continent - one of its seminal motivations. A more dimly perceived motivation, but perhaps more important aspect of its legacy, will be its impact on the discipline of seismology. The impacts are profound and broad, but I will speak only about one small area: the transformation of array-based surface wave seismology. Innovations stimulated by USArray include the creation of ambient noise tomography, the reformulation of the tomographic inverse problem in terms of local differential filters applied to observed travel time and amplitude fields, the extrication of subtle signals that reveal robust and independent information about anisotropy in the crust and mantle, and the joint interpretation with other kinds of geophysical data. Interpreting the results of these innovations in a Bayesian framework helps to define another legacy of USArray, the replacement of single models with statistical distributions of model variables that can be assimilated by researchers in other fields or by seismologists in the future. As we transition to considering the scientific legacy of USArray, it is important to remember Beno Gutenberg's faith in the power of data to resolve scientific dispute. As he stated in the next to last sentence of his remarkable book Physics of the Earth's Interior

  19. Methane over the North American Continent - INTEX-NA, Summer 2004

    NASA Astrophysics Data System (ADS)

    Karen, B.; Blake, D.; Meinardi, S.; Blake, N.; Sachse, G.; Slate, T.

    2005-12-01

    During July and August of 2004, the INTEX-NA mission was flown over the North American continent as a part of the integrated ICARTT campaign. Its primary focus was to examine the intercontinental transport and transformation of chemically and radiatively important trace gases and aerosols across the region. As a part of the mission, methane (CH4) was sampled using both canisters and a fast response tunable diode laser, the DACOM instrument. Agreement between the two techniques was excellent. Sources of methane are both natural (wetlands, wildfires) and anthropogenically controlled (landfills, ruminants, petroleum production and use, coal mining). Although natural biogenic emissions would be expected to be near seasonal maximums, the majority of North American wetlands are located in Canada and Alaska, and were difficult to isolate during the mission. Overall distributions were well correlated with C2Cl4, a tracer of industrial and urban activity, and reflect the widespread impact of anthropogenic emissions. As expected for a gas with surface continental sources, variability was greatest in the near-surface atmosphere and decreased with increasing altitude and distance from the continent. Summer convective activity over the region resulted in elevated concentrations measured at altitudes above 6 km. Enhanced levels with distinctive trace gas signatures were observed for a variety of sources, including petroleum mining and distribution, coal mining, Canadian wildfires, and aged Asian plumes advected across the Pacific. Several flights during the mission were flown along the U.S. east coast to sample air masses transported off the continent to the Atlantic. In the near-surface over the ocean, clean boundary layer air with mixing ratios comparable to background CMDL levels at this time were encountered. At altitudes above about 4 km, CH4 was enhanced by roughly 20-50 ppb.

  20. High-Resolution Genotyping of Campylobacter upsaliensis Strains Originating from Three Continents

    PubMed Central

    Lentzsch, P.; Rieksneuwöhner, B.; Wieler, L. H.; Hotzel, H.; Moser, I.

    2004-01-01

    Ninety-six Campylobacter upsaliensis strains that originated from Australia, Canada, and Europe (Germany) and that were isolated from humans, dogs, and cats were serotyped for their heat-stable surface antigens. All of them were genotyped by enterobacterial repetitive intergenic consensus sequence PCR (ERIC-PCR) profiling, and 83 strains were genotyped by macrorestriction analysis with the endonuclease XhoI. Eighty-four percent of the strains belonged to five different serotypes (serotypes OI, OII, OIII, OIV, and OVI), with the proportions of strains in each serotype being comparable among the groups of strains from all three continents. Two serotypes, OIII and OIV, were prevalent at rates of 35 to 40%. Serotypes OI, OII, and OVI were detected at rates of 1.5 to 15%. Between 10 and 17.7% of the strains did not react with the available antisera. Analysis of the ERIC-PCR profiles revealed two distinct genotypic clusters, which represented the German and the non-European strains, respectively. XhoI macrorestriction yielded two genotypic clusters; one of them contained 80.2% of the German strains and 34.6% of the non-European strains, and the second cluster consisted of 65.4% of the non-European strains and 19.8% of the German strains. Fourteen strains from all three continents were analyzed for their 16S rRNA gene sequences. Only two minor variations were detected in four of the strains. In conclusion, C. upsaliensis has undergone diverging processes of genome arrangement on different continents during evolution without segregating into different subspecies. PMID:15297481

  1. Moisture transport by Atlantic tropical cyclones onto the North American continent

    NASA Astrophysics Data System (ADS)

    Xu, Guangzhi; Osborn, Timothy J.; Matthews, Adrian J.

    2016-07-01

    Tropical Cyclones (TCs) are an important source of freshwater for the North American continent. Many studies have tried to estimate this contribution by identifying TC-induced precipitation events, but few have explicitly diagnosed the moisture fluxes across continental boundaries. We design a set of attribution schemes to isolate the column-integrated moisture fluxes that are directly associated with TCs and to quantify the flux onto the North American Continent due to TCs. Averaged over the 2004-2012 hurricane seasons and integrated over the western, southern and eastern coasts of North America, the seven schemes attribute 7-18 % (mean 14 % ) of total net onshore flux to Atlantic TCs. A reduced contribution of 10 % (range 9-11 % ) was found for the 1980-2003 period, though only two schemes could be applied to this earlier period. Over the whole 1980-2012 period, a further 8 % (range 6-9 % from two schemes) was attributed to East Pacific TCs, resulting in a total TC contribution of 19 % (range 17-22 % ) to the ocean-to-land moisture transport onto the North American continent between May and November. Analysis of the attribution uncertainties suggests that incorporating details of individual TC size and shape adds limited value to a fixed radius approach and TC positional errors in the ERA-Interim reanalysis do not affect the results significantly, but biases in peak wind speeds and TC sizes may lead to underestimates of moisture transport. The interannual variability does not appear to be strongly related to the El Niño-Southern Oscillation phenomenon.

  2. Scale interaction between the MJO and the diurnal cycle of precipitation over the Maritime Continent

    NASA Astrophysics Data System (ADS)

    Peatman, Simon; Matthews, Adrian; Stevens, David

    2013-04-01

    The Maritime Continent is a highly-populated region of many islands and shallow oceans, located in the oceanic warm pool, between the Indian and Pacific Oceans. A strong diurnal cycle of precipitation exists due to onshore breezes causing strong convergence of moist air - enhanced by topographic effects - over the land during the day time, peaking during afternoon-evening. The respective diurnal cycle over the ocean is far weaker and does not peak until early in the morning. On intra-seasonal time-scales the greatest source of variability in the tropics is the Madden-Julian Oscillation (MJO). The convectively active part of the MJO propagates slowly (~5 ms-1) eastward through the warm pool from the Indian Ocean to the western Pacific, followed by the convectively suppressed part. The complex topography of the Maritime Continent means the exact nature of the propagation through this region is unclear. Model simulations of the MJO are often poor over the region, leading to errors in latent heat release and, subsequently, global errors in medium-range weather prediction and climate simulation. Using 14 northern hemisphere winters of high-resolution satellite data it is shown that, over regions where the diurnal cycle is strong, more than 80% of the variance in precipitation during an MJO cycle is accounted for by changes in the amplitude of the diurnal cycle. A canonical view of the MJO is of smooth eastward progression of a large-scale precipitation envelope over the warm pool. However, by computing "MJO harmonics" it is shown that the leading edge of the precipitation envelope advances over the islands of the Maritime Continent approximately 6 days or 2000 km ahead of the main body. This behaviour can be accommodated within existing theories of MJO propagation. When the active convective MJO envelope is over the eastern Indian Ocean, frictional moisture convergence and topographic blocking in the easterlies of the equatorial Kelvin wave response supply moisture to

  3. Gravity domains and assembly of the North American continent by collisional tectonics

    NASA Technical Reports Server (NTRS)

    Thomas, M. D.; Grieve, R. A. F.; Sharpton, V. L.

    1988-01-01

    A gravity trend map of North America, based on a horizontal Bouguer gravity gradient map produced from gravity data for Canada and the conterminous United States, is presented and used to define a continental mosaic of gravity trend domains akin to structural domains. Contrasting trend characteristics at gravity domain boundaries support the concept of outward growth of the continent primarily by accretionary tectonics. Gravity patterns, however, indicate a different style of tectonics dominated in the development of now-buried Proterozoic orogenic belts in the south-central United States, supporting a view that these belts formed along the leading edge of a southward-migrating Proterozoic continental margin.

  4. The CONTIN algorithm and its application to determine the size distribution of microgel suspensions

    SciTech Connect

    Scotti, A.; Liu, W.; Hyatt, J. S.; Fernandez-Nieves, A.; Herman, E. S.; Lyon, L. A.; Choi, H. S.; Kim, J. W.; Gasser, U.

    2015-06-21

    We review a powerful regularization method, known as CONTIN, for obtaining the size distribution of colloidal suspensions from dynamic light scattering data. We show that together with the so-called L-curve criterion for selecting the optimal regularization parameter, the method correctly describes the average size and size distribution of microgel suspensions independently characterized using small-angle neutron scattering. In contrast, we find that when using the default regularization process, where the regularizer is selected via the “probability to reject” method, the results are not as satisfactory.

  5. Continental scale shear wave splitting analysis: Investigation of seismic anisotropy underneath the Australian continent

    NASA Astrophysics Data System (ADS)

    Heintz, Maggy; Kennett, Brian L. N.

    2005-07-01

    The structure of the upper mantle beneath the Australian continent is investigated using teleseismic shear wave splitting to extract seismic anisotropy. Measurements have been performed on data recorded at 190 sites with portable broadband seismic recorders, spanning almost the entire surface of the continent since 1992. The average time span of the various deployments, primarily designed for surface wave tomography, is 6 months, which is rather limited for shear wave splitting analysis. However, the data set provides a full continental scale survey using the reasonably favourable distribution of seismicity to Australia. Seismic anisotropy has the potential to provide insights into the lithospheric structure and the possible mechanical coupling between the crust and the upper mantle, but prior results for Australia have indicated relatively small levels of splitting and a complex pattern. These results are confirmed with our new and far more extensive measurements across the whole continent. The pattern of seismic anisotropy from shear wave splitting beneath Australia is rather complex and is not correlated with the almost north-south absolute plate motion (APM) from recent models. Deviation of the asthenospheric mantle flow around the lithospheric roots associated with the extensive Archaean and Proterozoic zones of central and western Australia could be occurring, and so mantle flow-related anisotropy cannot be completely ruled out. Despite the limited geological outcrop, especially in Phanerozoic eastern Australia, that is almost entirely covered by sedimentary basins, some relationships can be highlighted between the orientation of the polarization plane of the fast S-waves and structural trends along, for instance, the Halls Creek orogen bordering the eastern edge of the Kimberley basin or along the New England and Lachlan fold belts in the southeastern part of the continent. Such relationships might account for anisotropy frozen in the lithosphere during post

  6. Homogeneous magnitude system of the Eurasian continent: S and L waves

    NASA Astrophysics Data System (ADS)

    Christoskov, L.; Kondorskaya, N. V.; Vanek, J.

    1983-07-01

    A research project was started by the Commission of Academies of Socialist Countries on Planetary Geophysics (KAPG) to establish a system of seismic reference stations of the Eurasian continent for determining reliable earthquake magnitudes. This system was called the Homogeneous Magnitude System (HMS), and seismologist of 13 institutions from Bulgaria, Czechoslovakia, German Democratic Republic, Poland, and the U.S.S.R. participated. The project was sponsored by the Commission on Practice of the International Association of Seismology and Physics of the Earth's Interior, which created a special working group for homogeneous magnitude system within its Subcommission on Magnitude.

  7. Magnetotelluric Imaging of an Arc-Continent Collision Beneath Central Taiwan

    NASA Astrophysics Data System (ADS)

    Bertrand, E. A.; Unsworth, M. J.; Chiang, C.; Chen, C.; Turkoglu, E.; Hsu, H.; Hill, G. J.

    2007-12-01

    Arc-continent collisions are a fundamental part of the plate tectonic cycle and play an important role in mountain building and the growth of continents. Studying this process in ancient orogens is often hindered by tectonic overprinting and poorly resolved synorogenic plate kinematics and tectonic settings. The Taiwan arc-continent collision between the Luzon arc and the Eurasian continental margin is one of the most active arc-continent collisions in the world. The current plate motions and surface geology are well understood, making Taiwan an ideal location for geophysical investigations of this important tectonic process. The Taiwan Integrated Geodynamical Research (TAIGER) project was initiated in 2004 to image the lithospheric structure beneath Taiwan. The project includes the acquisition of both active and passive seismic data plus detailed magnetotellurics (MT) surveys. MT is a passive geophysical technique which records time variations of natural electromagnetic fields at the surface of the Earth and can determine the subsurface resistivity. This parameter can be used to constrain lithospheric composition and strength. Over the fall of 2006 and spring of 2007, 82 long-period MT soundings were acquired in Taiwan. The fieldwork was accomplished by collaboration between the University of Alberta and National Central University of Taiwan. In fall 2007, collection of additional broadband MT will complement these data. The long-period data were processed using robust techniques and remotely referenced with a station on the PengHu islands (~100km from the nearest site) to reduce the influence of cultural noise. The conductive Taiwan strait separating PengHu from the mainland acts as an effective attenuator of cultural EM fields. Two closely spaced parallel transects across central Taiwan are formed by 46 of these stations with a nominal spacing of 5km. Dimensionality analysis of these transects using the McNeice-Jones tensor decomposition algorithm reveal local 3

  8. The role of the Malone antegrade continence enema (MACE) in the management of myelodeysplatic patients.

    PubMed

    Zamilpa, Ismael; Koyle, Martin A

    2009-01-01

    Myelodysplasia is a congenital neural tube defect commonly affecting bladder and bowel function. Management of fecal incontinence is paramount to achieve patient independence and self-confidence. When conservative measures fail alternative invasive methods can be successfully applied. The Malone antegrade continence enema (MACE) was introduced in the late 1980's to treat spina bifida patients with fecal incontinence refractory to conservative management. Since its introduction, multiple successful variations have been described and its role has expanded. Indeed, the MACE has revolutionized the care of myelodysplastic patients, their bowel function, and ultimately their self image. PMID:21791795

  9. Lithospheric strength across the ocean-continent transition in the NW of the Iberian Peninsula

    NASA Astrophysics Data System (ADS)

    Martín-Velázquez, Silvia; Martín-González, Fidel

    2014-05-01

    The main objective of this work is to investigate the relation between the strength of the lithosphere and the observed pattern of seismicity across the ocean-continent transition in the NW margin of the Iberian Peninsula. The seismicity is diffuse in this intraplate area, far from the seismically active margin of the plate: the Eurasia-African plate boundary, where convergence occurs at a rate of 4-5mm/year. The earthquake epicentres are mainly limited to an E-W trending zone (onshore seismicity is more abundant than offshore), and most earthquakes occur at depths less than 30 km, however, offshore depths are up to 150 km). Moreover, one of the problems to unravel in this area is that the seismotectonic interpretations of the anomalous seismicity in the NW peninsular are contradictory. The temperature and strength profiles have been modelled in three domains along the non-volcanic rifted West Iberian Margin: 1) the oceanic lithosphere of the Iberian Abyssal Plain, 2) the oceanic lithosphere near the ocean-continent transition of the Galicia Bank, and 3) the continental lithosphere of the NW Iberian Massif. The average bathymetry and topography have been used to fit the thermal structures of the three types of lithospheres, given that the heat flow and heat production values show a varied range. The geotherms, together with the brittle and ductile rheological laws, have been used to calculate the strength envelopes in different stress regimes (compression, shear and tensile). The continental lithosphere-asthenosphere boundary is located at 123 km and several brittle-ductile transitions appear in the crust and the mantle. However, the oceanic lithospheres are thinner (110 km near the Galicia Bank and 87 km in the Iberian Abbysal Plain) and more simple (brittle behaviour in the crust and upper mantle). The earthquake distribution is best explained by lithospheres with dry compositions and shear or tensile stress regimes. These results are similar can be compared to

  10. Evaluating mid-Holocene precipitation over Australasia and the Maritime Continent in climate models

    NASA Astrophysics Data System (ADS)

    Ackerley, Duncan; Reeves, Jessica

    2015-04-01

    The Australasian INTIMATE (INTegration of Ice-core, Marine and Terrestrial records) initiative (INQUA project #0809) was undertaken to develop a consistent chronological assessment of the climate of the past 30000 years over Australia, New Zealand and the Maritime Continent. Work has continued as part of SHAPE initiative (INQUA project #1302), but there has currently been little use of this comprehensive resource for evaluating the available climate model data. Therefore, this work presents the initial assessment of model simulations of the mid-Holocene over the Australasian and Maritime Continents (taken from the Paleoclimate Modelling Intercomparison Project, PMIP) in relation to those available data. The mid-Holocene (6 ka) encompasses a period after sea level stabilisation (around 8-7.5 ka) and before the onset of strong ENSO-related variability (post 4 ka). There is some evidence of possibly drier conditions over northern Australia with increased coastal dune activity, along with slightly wetter conditions over Borneo and Papua New Guinea. Weakening of the Southern Hemisphere mid-latitude westerlies (relative to the early Holocene) is also likely to have occurred, as evidenced by drier conditions in Western Tasmania and Victoria. The modelled results from the mid-Holocene simulations indicate that conditions were approximately 1-6% drier over much of continental Australia than at present. There is also evidence of slightly wetter conditions (1-3%) over the northern tip of Australia and parts of Papua New Guinea and Borneo. The Southern Hemisphere westerlies in the mid-latitudes (around 50S) are also weaker by 1-2 m s-1 in the model simulations. There are also differences in the seasonal cycle of precipitation and circulation in these models in response to the changes in the orbital parameters in the mid-Holocene relative to present day. The precipitation in the early half of the monsoon season (October, November and December-OND) is typically 10% higher in the

  11. The Promotion and Marketing of OxyContin: Commercial Triumph, Public Health Tragedy

    PubMed Central

    2009-01-01

    I focus on issues surrounding the promotion and marketing of controlled drugs and their regulatory oversight. Compared with noncontrolled drugs, controlled drugs, with their potential for abuse and diversion, pose different public health risks when they are overpromoted and highly prescribed. An in-depth analysis of the promotion and marketing of OxyContin illustrates some of the associated issues. Modifications of the promotion and marketing of controlled drugs by the pharmaceutical industry and an enhanced capacity of the Food and Drug Administration to regulate and monitor such promotion can have a positive impact on the public health. PMID:18799767

  12. Organic geochemistry of Mid-Continent middle and Late Ordovician oils

    SciTech Connect

    Longman, M.W.; Palmer, S.E.

    1987-08-01

    Ordovician oils in Mohawkian and Cincinnatian reservoirs of the US Mid-Continent retain the biochemical imprint of Middle and Upper Ordovician oceanic life before the evolution of land plants and most vertebrates. Thus, these oils have some geochemical features that distinguish them from younger oils. These features include (1) a predominance of n-C/sub 15/, n-C/sub 17/, and n-C/sub 19/ alkanes in the saturated hydrocarbon fraction, (2) relatively low amounts of longer chain n-alkanes, (3) low amounts of chlorophyll-derived isoprenoids, such as pristane and phytane, and (4) abundant C/sub 29/ sterane relative to C/sub 27/ with rearranged forms (diasteranes) predominant over normal steranes. Ordovician oils also generally contain little sulfur and have a somewhat variable light stable carbon isotopic composition with delta/sup 13/C/sub sat/ and delta/sup 13/C/sub aro/ values of -28 to -31 per thousand (PDB), but these features are typical of many marine oils. The unusual chemistry of these Ordovician oils supports the interpretation of Reed, Illich, and Horsfield (1986) that prokaryotic organisms provided the organic matter for most Ordovician oils. Although their claim for Gloeocapsamorpha (a problematic unicellular prokaryote, possibly a blue-green alga or an unusually large bacterium) cannot be proven from oil chemistry alone, knowing that indigenous Mid-Continent Ordovician oils were derived from prokaryotic organisms may aid in future exploration for these reservoirs. 7 figures, 3 tables.

  13. Polychlorinated terphenyl patterns and levels in selected marine mammals and a river fish from different continents.

    PubMed

    Rosenfelder, Natalie; Vetter, Walter

    2014-01-01

    Polychlorinated terphenyls (PCTs) are a class of persistent organic pollutants which have been used from the 1920s to the 1980s for similar purposes as polychlorinated biphenyls (PCBs). Comparably little data was available on the PCT distribution in the environment mainly due to analytical difficulties in their determination. By means of a calculation algorithm recently developed we now studied the PCT pattern in individual marine mammal samples and one fish sample from different continents. Altogether, 97 PCTs were detected in eight samples and twelve to 66 tetra- to nonachloroterphenyl (tetra- to nonaCT) congeners were detected in individual samples. PCTs were present in all marine mammal samples which originated from four continents, but the PCT pattern was varied. TetraCTs were dominant in the sample from Africa, Australia, Spitsbergen (European Arctic) and in a sample from the Baltic Sea, heptaCTs in samples from the North Sea and octaCTs in a sample from Iceland. The abundance of sumPCTs relative to PCB 153, estimated from the GC/ECNI-MS response corrected for the degree of chlorination, ranged from 0.9 to 8.8%, corresponding with ~0.22-2.2% of the total PCB content. The highest PCT level detected was 980 mg/kg lipid in a harbour seal from the North Sea, Germany. The results from this study indicated that samples from certain areas, e.g. the North Sea may still be polluted with PCTs. PMID:24211498

  14. Tectonic evolution of Late Cenozoic arc-continent collision in Taiwan

    SciTech Connect

    Teng, L.S. )

    1990-06-01

    The island of Taiwan is an active orogen formed by the collision between the Luzon arc and the Asian continent. The kinematic progression of the arc-continent collision can be reconstructed by superimposing the restored paleopositions of Luzon arc upon the precollisional Asian continental margin. The geological history of the collision can be interpreted from the rock records of the mountain ranges of Taiwan. By incorporating geological information into plate kinematics, the collision can be attributed to the northwesterly impingement of the Luzon arc upon the continental margin in the last 12 million years. During the initial stage of the collision, some of the continental materials might have been metamorphosed in the deep subduction zone, but no distinct effects can be perceived in the sedimentary record. In the Mio-Pliocene time (about 5 Ma), the accretionary wedge grew large enough to become a sediment source for the Luzon forearc basin and to induce foreland subsidence on the continental margin. In the early late Pliocene (about 3 Ma), drastic collision caused rapid uplift of the collision orogen that shed voluminous orogenic sediments into the forearc and foreland basins. Continued collision progressively accreted the forearc and foreland basins to the collision orogen from north to south to the present configuration.

  15. Implications of the Projected Future Climate on Water Resources in the Indian Sub-continent Basins

    NASA Astrophysics Data System (ADS)

    Shah, H. L.; Mishra, V.

    2014-12-01

    Sustainability of water resources is vital for agricultural and socio-economic development in India. In the recent few decades, India has been witnessing erratic nature of the Indian summer monsoon, which accounts for about 80% of the total annual rainfall. While there is a large uncertainty in the precipitation projections during the summer monsoon from the regional and global climate models, we need to understand sensitivity of water resources in the Indian sub-continental river basins under the projected future climate. This is particularly important as the Indian sub-continent is one of the most populated regions of the world. We evaluated changes in water budget in the 18 Indian sub-continental basins under the projected future climate using the Variable Infiltration Capacity (VIC) model. The VIC model was calibrated and evaluated using the observed streamflow as well as satellite derived evapotranspiration and soil moisture. After the successful calibration and evaluation, we performed a sensitivity analysis for the water balance variables. Finally, we used downscaled and bias corrected climate forcings to develop scenarios of changes in water balance under the future climate. Despite the intermodal variation, Indian basins are projected to experience wetter and warmer climate in future. Results indicate positive changes in evapotranspiration and runoff under the projected future climate; however, increases in total runoff are projected to be significant in most of the basins in the sub-continent.

  16. American Exceptionalism: Population Trends and Flight Initiation Distances in Birds from Three Continents

    PubMed Central

    Møller, Anders Pape; Samia, Diogo S. M.; Weston, Mike A.; Guay, Patrick-Jean; Blumstein, Daniel T.

    2014-01-01

    Background All organisms may be affected by humans' increasing impact on Earth, but there are many potential drivers of population trends and the relative importance of each remains largely unknown. The causes of spatial patterns in population trends and their relationship with animal responses to human proximity are even less known. Methodology/Principal Finding We investigated the relationship between population trends of 193 species of bird in North America, Australia and Europe and flight initiation distance (FID); the distance at which birds take flight when approached by a human. While there is an expected negative relationship between population trend and FID in Australia and Europe, we found the inverse relationship for North American birds; thus FID cannot be used as a universal predictor of vulnerability of birds. However, the analysis of the joint explanatory ability of multiple drivers (farmland breeding habitat, pole-most breeding latitude, migratory habit, FID) effects on population status replicated previously reported strong effects of farmland breeding habitat (an effect apparently driven mostly by European birds), as well as strong effects of FID, body size, migratory habit and continent. Farmland birds are generally declining. Conclusions/Significance Flight initiation distance is related to population trends in a way that differs among continents opening new research possibilities concerning the causes of geographic differences in patterns of anti-predator behavior. PMID:25226165

  17. Continent-wide survey reveals massive decline in African savannah elephants

    PubMed Central

    Schlossberg, Scott; Griffin, Curtice R.; Bouché, Philippe J.C.; Djene, Sintayehu W.; Elkan, Paul W.; Ferreira, Sam; Grossman, Falk; Kohi, Edward Mtarima; Landen, Kelly; Omondi, Patrick; Peltier, Alexis; Selier, S.A. Jeanetta; Sutcliffe, Robert

    2016-01-01

    African elephants (Loxodonta africana) are imperiled by poaching and habitat loss. Despite global attention to the plight of elephants, their population sizes and trends are uncertain or unknown over much of Africa. To conserve this iconic species, conservationists need timely, accurate data on elephant populations. Here, we report the results of the Great Elephant Census (GEC), the first continent-wide, standardized survey of African savannah elephants. We also provide the first quantitative model of elephant population trends across Africa. We estimated a population of 352,271 savannah elephants on study sites in 18 countries, representing approximately 93% of all savannah elephants in those countries. Elephant populations in survey areas with historical data decreased by an estimated 144,000 from 2007 to 2014, and populations are currently shrinking by 8% per year continent-wide, primarily due to poaching. Though 84% of elephants occurred in protected areas, many protected areas had carcass ratios that indicated high levels of elephant mortality. Results of the GEC show the necessity of action to end the African elephants’ downward trajectory by preventing poaching and protecting habitat.

  18. Repeated arc-continent collision as a key mechanism for continental growth

    NASA Astrophysics Data System (ADS)

    Aitchison, J.; Buckman, S.

    2011-12-01

    Prevailing 'consensus' models for the Phanerozoic development of eastern Australia invoke a retreating accretionary orogen model in which slab retreat results in development of offshore island arcs in front of marginal basins. Periodically these basins close and the arcs are retro-thrust back onto the continental margin. Implicit in this model is the notion that all elements develop in an upper plate location upon the accretionary margin and that west-dipping subduction beneath eastern Gondwana was a long-lived phenomenon. We suggest this concept is flawed and instead propose a new testable hypothesis that eastern Australia grew through a series of arc-continent collisions in which east-directed subduction beneath intra-oceanic island arcs led to their collision with eastern Australia. At least four such arc-continent collisions are posited in mid-Cambrian (Mt Stavely arc), Late Ordovician (Macquarie arc), mid-Devonian (Gamilaroi arc) and Late Permian (Gympie arc) times. This process effectively transferred new material to the continental crust resulting in net growth. When collisions were followed by subduction flip episodes of west-directed subduction beneath the continental margin ensued giving rise to the S- and I-type granites for which eastern Australia is famous.

  19. Paleokarst and fracture overprints in Mid-Continent carbonates in evaluation of horizontal drilling potential

    SciTech Connect

    Fritz, R.D.; Shelton, J.W. ); Esteban, M. ); Wilson, J.L.

    1991-03-01

    The Mid-Continent region, especially in Oklahoma and Arkansas, contains thick Paleozoic carbonate sections that are dolomitic and karstic in character. These sections commonly exhibit strong structural overprints, including intense fracturing, due primarily to Pennsylvanian orogenies. Because of their rather wide association with source rocks, these carbonates are thought to represent good potential targets for horizontal drilling. The Cambro-Ordovician Arbuckle Group, the Ordovician Viola Group, the Siluro-Devonian Hunton Group, and the Mississippian Limestone all contain zones that are locally productive. These stratigraphic units are either uniformly tight or they are heterogeneous with complex porosity profiles. In karst terranes both types commonly occur together; both require fracturing to increase porosity and permeability. Both youthful and mature stages of paleokarst are observed in the Arbuckle Group; the best porosity is developed in the youthful stage. These stages can develop microporous, planar porous, or macroporous types of reservoir geometry. All of these may be heterogeneous in nature, requiring fractures to interconnect porous intervals. Horizontal drilling is yet to be proved as a reliable method for increasing production efficiency in Mid-Continent carbonates. An evaluation of diagenetic history, especially karst processes, along with local and regional structural settings, may provide a key for improved understanding of the horizontal drilling potential in these carbonates.

  20. Phylogeography of the Microcoleus vaginatus (Cyanobacteria) from Three Continents – A Spatial and Temporal Characterization

    PubMed Central

    Dvořák, Petr; Hašler, Petr; Poulíčková, Aloisie

    2012-01-01

    It has long been assumed that cyanobacteria have, as with other free-living microorganisms, a ubiquitous occurrence. Neither the geographical dispersal barriers nor allopatric speciation has been taken into account. We endeavoured to examine the spatial and temporal patterns of global distribution within populations of the cyanobacterium Microcoleus vaginatus, originated from three continents, and to evaluate the role of dispersal barriers in the evolution of free-living cyanobacteria. Complex phylogeographical approach was applied to assess the dispersal and evolutionary patterns in the cyanobacterium Microcoleus vaginatus (Oscillatoriales). We compared the 16S rRNA and 16S-23S ITS sequences of strains which had originated from three continents (North America, Europe, and Asia). The spatial distribution was investigated using a phylogenetic tree, network, as well as principal coordinate analysis (PCoA). A temporal characterization was inferred using molecular clocks, calibrated from fossil DNA. Data analysis revealed broad genetic diversity within M. vaginatus. Based on the phylogenetic tree, network, and PCoA analysis, the strains isolated in Europe were spatially separated from those which originated from Asia and North America. A chronogram showed a temporal limitation of dispersal barriers on the continental scale. Dispersal barriers and allopatric speciation had an important role in the evolution of M. vaginatus. However, these dispersal barriers did not have a permanent character; therefore, the genetic flow among populations on a continental scale was only temporarily present. Furthermore, M. vaginatus is a recently evolved species, which has been going through substantial evolutionary changes. PMID:22761955

  1. Usefulness of Anorectal Manometry for Diagnosing Continence Problems After a Low Anterior Resection

    PubMed Central

    Samalavicius, Narimantas E.

    2016-01-01

    Purpose For several decades, the low anterior resection (LAR) with total mesorectal excision (TME) has been the gold standard for treating patients with rectal cancer. Up to 90% of patients undergoing sphincter-preserving surgery will have changes in bowel habits, so-called 'anterior resection syndrome.' This study examined patients' continence after a LAR for the treatment of rectal cancer. Methods This prospective study was performed between September 2014 and August 2015 at the National Cancer Institute and included 30 patients who underwent anorectal manometry preoperatively and at 3 and 4 months after a LAR, but 10 were excluded from further evaluation for various reasons. Wexner score was recorded preoperatively and 4 months after LAR (1 month after ileostomy repair). Results Postoperatively, 70% of patients complained of some degree of soiling (incontinence to liquid stool), and 30% experienced urgent defecation. Four months after surgery, these symptoms had somewhat abated. The anal resting pressure and the maximum squeezing pressure did not change significantly. Rectal capacity and compliance were reduced in all patients. The majority of patients demonstrated manometric anorectal changes and clinical anorectal function disorders during the first 4 months after surgery. The Wexner scores and the manometric findings showed no correlation. Conclusion Many patients undergoing a LAR with TME for the treatment of rectal cancer experience some degree of incontinence postoperatively. Anorectal manometry may be used as an additional tool for evaluating problems with continence after a LAR. No correlation between the Wexner score and the manometric findings was observed. PMID:27437391

  2. Comparing determinants of alien bird impacts across two continents: implications for risk assessment and management

    PubMed Central

    Evans, Thomas; Kumschick, Sabrina; Dyer, Ellie; Blackburn, Tim

    2014-01-01

    Invasive alien species can have serious adverse impacts on both the environment and the economy. Being able to predict the impacts of an alien species could assist in preventing or reducing these impacts. This study aimed to establish whether there are any life history traits consistently correlated with the impacts of alien birds across two continents, Europe and Australia, as a first step toward identifying life history traits that may have the potential to be adopted as predictors of alien bird impacts. A recently established impact scoring system was used in combination with a literature review to allocate impact scores to alien bird species with self-sustaining populations in Australia. These scores were then tested for correlation with a series of life history traits. The results were compared to data from a previous study in Europe, undertaken using the same methodology, in order to establish whether there are any life history traits consistently correlated with impact across both continents. Habitat generalism was the only life history trait found to be consistently correlated with impact in both Europe and Australia. This trait shows promise as a potential predictor of alien bird impacts. The results support the findings of previous studies in this field, and could be used to inform decisions regarding the prevention and management of future invasions. PMID:25165531

  3. Onset of oxidative weathering of continents recorded in the geochemistry of ancient glacial diamictites

    NASA Astrophysics Data System (ADS)

    Gaschnig, Richard M.; Rudnick, Roberta L.; McDonough, William F.; Kaufman, Alan J.; Hu, Zhaochu; Gao, Shan

    2014-12-01

    Glacial diamictites deposited in the Mesoarchean, Paleoproterozoic, Neoproterozoic, and Paleozoic eras record temporal variations in their average compositions that reflect the changing composition of the upper continental crust (UCC). Twenty six of the 27 units studied show elevated chemical index of alternation (CIA) and low Sr abundances, regardless of their age, documenting pervasive weathering of the average UCC. Lower abundances of transition metals reflect a shift towards more felsic crustal compositions after the Archean. Superimposed on this chemical difference is the signal of the rise of oxidative weathering of the continents, recorded by changes in the absolute and relative abundances of the redox sensitive elements Mo and V. Neoproterozoic and Paleozoic diamictites show pervasive depletion in Mo and V, reflecting their loss from the continents due to increasing intensity of oxidative weathering, as also recorded in some of the Paleoproterozoic diamictites. A few of the Paleoproterozoic diamictites deposited after the Great Oxidation Event show no depletion in Mo and V (e.g., Gowganda), but such signatures could be inherited from their provenance. In contrast, the pre-GOE Duitschland diamictite (ca. 2.3-2.5 Ga) from South Africa reveals evidence of intense oxidative weathering (i.e., large depletions in Mo), supporting a growing body of observations showing the presence of measurable atmospheric oxygen prior to permanent loss of the mass independent fractionation signal in sulfur isotopes.

  4. The further development of the active urine collection device: a novel continence management system.

    PubMed

    Tinnion, E; Jowitt, F; Clarke-O'Neill, S; Cottenden, A M; Fader, M; Sutherland, I

    2003-01-01

    Continence difficulties affect the lives of a substantial minority of the population. Women are far more likely than men to be affected by urinary incontinence but the range of management options for them is limited. There has been considerable interest in developing an external urine collection system for women but without success to date. This paper describes the development and preliminary clinical testing of an active urine collection device (AUCD), which could provide a solution for sufferers. The device uses stored vacuum, protected by a high bubble point filter, to remove urine as quickly as it is produced. This allows a small battery-operated pump to provide the required vacuum, enabling the device to be portable. Two different types of non-invasive patient/device interface were developed, and tested by volunteers: urinal and small pad. The slimline urinal was popular with users although liquid noise was a problem. The pad interface was successful on occasions but further work is necessary to produce a reliable pad. This study has successfully demonstrated that a prototype AUCD liquid handling system can remove urine at clinically relevant flowrates. While further development is required, volunteer tests have shown that the AUCD could be a useful advance in continence management. PMID:12885199

  5. Convergence across a continent: adaptive diversification in a recent radiation of Australian lizards.

    PubMed

    Blom, Mozes P K; Horner, Paul; Moritz, Craig

    2016-06-15

    Recent radiations are important to evolutionary biologists, because they provide an opportunity to study the mechanisms that link micro- and macroevolution. The role of ecological speciation during adaptive radiation has been intensively studied, but radiations can arise from a diversity of evolutionary processes; in particular, on large continental landmasses where allopatric speciation might frequently precede ecological differentiation. It is therefore important to establish a phylogenetic and ecological framework for recent continental-scale radiations that are species-rich and ecologically diverse. Here, we use a genomic (approx. 1 200 loci, exon capture) approach to fit branch lengths on a summary-coalescent species tree and generate a time-calibrated phylogeny for a recent and ecologically diverse radiation of Australian scincid lizards; the genus Cryptoblepharus We then combine the phylogeny with a comprehensive phenotypic dataset for over 800 individuals across the 26 species, and use comparative methods to test whether habitat specialization can explain current patterns of phenotypic variation in ecologically relevant traits. We find significant differences in morphology between species that occur in distinct environments and convergence in ecomorphology with repeated habitat shifts across the continent. These results suggest that isolated analogous habitats have provided parallel ecological opportunity and have repeatedly promoted adaptive diversification. By contrast, speciation processes within the same habitat have resulted in distinct lineages with relatively limited morphological variation. Overall, our study illustrates how alternative diversification processes might have jointly stimulated species proliferation across the continent and generated a remarkably diverse group of Australian lizards. PMID:27306048

  6. Evolution of female urinary continence after physical therapy and associated factors

    PubMed Central

    2014-01-01

    Background Urinary incontinence (UI) is defined as any involuntary loss of urine that can influence the quality of life, personal hygiene and social interaction. The types of UI that most affect women are stress urinary incontinence, urge incontinence and mixed urinary incontinence. There are several risk factors that result in specific treatments. We aimed to investigate the evolution of female urinary continence after physical therapy intervention and its associated factors. Method A retrospective cross-sectional study was conducted with 71 participants who were discharged from physiotherapy sector from August 2006 to April 2012 and met the inclusion criteria. Results Among the studied variables, the number of sessions and completion of home pelvic floor exercises showed a significant association. The urinary continence appeared in 43.7% of the cases, and factors, performance of home exercises, and number of sessions showed a significant association. Conclusion The number of sessions and completion of home pelvic floor exercises showed a significant relationship with each other. PMID:24839462

  7. Circumpolar oil-and-gas-bearing basins of the arctic part of the North American continent

    NASA Astrophysics Data System (ADS)

    Zabanbark, A.; Lobkovsky, L. I.

    2015-09-01

    Major geotectonic elements of the reviewed territory of the Arctic part of the North American continent are the Hyperborean Precambrian Platform, the Franklin folding belt, the northern part of the Precambrian Canadian platform, and the Mesozoic folding belt of Canada and Alaska. The rise of the Arctic slope of Alaska, the Beaufort Sea, and the Sverdrup basin are located in the southern margins of the Hyperborean Platform. The structure and peculiarities of development of these structural elements are genetically related to the evolution of this platform, as well as the current state of petroleum potential of the most promising exploration region of Arctic in the 21st century. The forced exploration of the Arctic regions of the United States and Canada has become an important milestone in the current development of the world energetics. Up to 100 oil, gas, and gas condensate fields have been discovered as a result of violent studies, and the potential oil and gas reserves in the Arctic part of the North American continent have been estimated to 30 billiion t and 50 trillion cubic meters, respectively. Many prospects are related to the continental slopes of all three above-mentioned basins; the total potential reserves of slopes are estimated as 10-12 billion t of oil and 20-25 trillion cubic meters of gas.

  8. Development of clinical practice guidelines for urinary continence care of adult stroke survivors in acute and rehabilitation settings.

    PubMed

    Fisher, Andrea R

    2014-01-01

    This study developed evidence-based clinical practice guidelines for the urinary continence care of adult stroke survivors in acute and rehabilitation settings. The research team conducted a comprehensive review of the literature on urinary continence interventions and outcomes. The team then developed a set of recommendations outlined in the resulting clinical practice guidelines titled Clinical Practice Guidelines (CPGs) for the Urinary Continence Care of Stroke Survivors in Acute and Rehabilitation Settings. The evaluation of the CPGs consisted of a two-part assessment and pilot implementation. An expert panel of 25 local and regional experts in stroke and continence care assessed the proposed CPGs. This assessment consisted of two stages: a) evaluating the guidelines using the Appraisal of Guidelines Research and Evaluation (AGREE) Instrument (http://www. agreetrust.org); and, b) conducting focus groups to identify barriers and facilitators to the implementation of the guidelines using the Ottawa Model of Research Use (OMRU). Results from the expert panel assessments/feedback contributed to the refinement of the CPGs as well as identification and construction of implementation strategies. Two sites conducted a three-month pilot implementation of three recommendations from the CPGs as selected by each site. The two inpatient sites were a rehabilitation setting and a mixed acute and rehabilitation setting. The implementation of the CPGs included the development of learning strategies tailored to the needs of each site and in addition to the creation of an online self-learning portal. This study assessed nurses' knowledge, attitudes, and beliefs regarding urinary continence challenges using a survey before and after the pilot. Chart reviews before and after the pilot implementation audited the nurses' urinary continence practices for patients and uptake of the selected guidelines' recommendations. Study findings suggested the implementation of the CPGs

  9. Intermediate crust (IC); its construction at continent edges, distinctive epeirogenic behaviour and identification as sedimentary basins within continents: new light on pre-oceanic plate motions

    NASA Astrophysics Data System (ADS)

    Osmaston, Miles F.

    2014-05-01

    Introduction. The plate tectonics paradigm currently posits that the Earth has only two kinds of crust - continental and oceanic - and that the former may be stretched to form sedimentary basins or the latter may be modified by arc or collision until it looks continental. But global analysis of the dynamics of actual plate motions for the past 150 Ma indicates [1 - 3] that continental tectospheres must be immensely thicker and rheologically stiffer than previously thought; almost certainly too thick to be stretched with the forces available. In the extreme case of cratons, these tectospheric keels evidently extend to 600 km or more [2, 3]. This thick-plate behaviour is attributable, not to cooling but to a petrological 'stiffening' effect, associated with a loss of water-weakening of the mineral crystals, which also applies to the hitherto supposedly mobile LVZ below MORs [4, 5]. The corresponding thick-plate version of the mid-ocean ridge (MOR) process [6 - 8], replacing the divergent mantle flow model, has a deep, narrow wall-accreting axial crack which not only provides the seismic anisotropy beneath the flanks but also brings two outstanding additional benefits:- (i) why, at medium to fast spreading rates, MOR axes become straight and orthogonally segmented [6], (ii) not being driven by body forces, it can achieve the sudden jumps of axis, spreading-rate and direction widely present in the ocean-floor record. Furthermore, as we will illustrate, the crack walls push themselves apart at depth by a thermodynamic mechanism, so the plates are not being pulled apart. So the presence of this process at a continental edge would not imply the application of extensional force to the margin. Intermediate Crust (IC). In seeking to resolve the paradox that superficially extensional structures are often seen at margins we will first consider how this MOR process would be affected by the heavy concurrent sedimentation to be expected when splitting a mature continent. I reason

  10. Evolutionary conservatism and convergence both lead to striking similarity in ecology, morphology and performance across continents in frogs.

    PubMed

    Moen, Daniel S; Irschick, Duncan J; Wiens, John J

    2013-12-22

    Many clades contain ecologically and phenotypically similar species across continents, yet the processes generating this similarity are largely unstudied, leaving fundamental questions unanswered. Is similarity in morphology and performance across assemblages caused by evolutionary convergence or by biogeographic dispersal of evolutionarily conserved ecotypes? Does convergence to new ecological conditions erase evidence of past adaptation? Here, we analyse ecology, morphology and performance in frog assemblages from three continents (Asia, Australia and South America), assessing the importance of dispersal and convergent evolution in explaining similarity across regions. We find three striking results. First, species using the same microhabitat type are highly similar in morphology and performance across both clades and continents. Second, some species on different continents owe their similarity to dispersal and evolutionary conservatism (rather than evolutionary convergence), even over vast temporal and spatial scales. Third, in one case, an ecologically specialized ancestor radiated into diverse ecotypes that have converged with those on other continents, largely erasing traces of past adaptation to their ancestral ecology. Overall, our study highlights the roles of both evolutionary conservatism and convergence in explaining similarity in species traits over large spatial and temporal scales and demonstrates a statistical framework for addressing these questions in other systems. PMID:24174109

  11. Force Required to Breakup a Continent: Implications on Rifting Localization and Migration

    NASA Astrophysics Data System (ADS)

    Svartman Dias, A. E.; Lavier, L. L.; Hayman, N. W.

    2014-12-01

    The maximum force from ridge push available is about 5 TN/m, lower than that required by 2D and 3D numerical experiments to rift the lithosphere in the absence of magmatic input. We carry out 2D numerical experiments without any magmatic input to study the extensional force necessary to start a rift basin and to breakup a continent. We assume a range of initial temperature structure, crust and mantle initial thicknesses and composition. In a first step, we use velocity boundary conditions (1cm/yr) and we monitor the force necessary to breakup the continent. Results can be classified in two groups according to the amount of force needed to rift through time: (1) The initial force builds up rapidly to 12-20 TN/m within 0.4-1.0 Myr. This is followed by an exponential decrease due to early strain localization and lithospheric weakening. The force is < 5TN/m after 4.4-7.0 Myr of extension. Continental breakup occurs approximately 10 Myr after the onset of extension forming narrow conjugate margins. This group encompasses experiments with initial Tmoho < 650oC and crustal thicknesses ≤ 35 km, where crust and mantle deformation are coupled from the early stages of rifting. (2) The initial build-up is more discrete, from < 3 TN/m to 4-6.5 TN/m in the first 0.1 Myr, followed by a decrease to a nearly constant value of 3-5 TN/m from 0.4 Myr to 10 Myr, when strain starts localizing. The constant force through time reflects lithosphere strengthening and migration of the deformation. This rift migration forms a wide basin (> 250 km wide) that may evolve to form very asymmetric conjugate margins. Breakup occurs 18 Myr after the onset of rifting or later. This second group corresponds to experiments with initial Tmoho > 650 km and crustal thicknesses ≥ 35 km. High bending stresses result in upper crust brittle failure and on enhancement of lower crust lateral flow. Interaction between ductile failure in the lower crust and brittle failure in the upper crust controls the

  12. Pandemic Vibrio parahaemolyticus O3:K6 on the American continent

    PubMed Central

    Velazquez-Roman, Jorge; León-Sicairos, Nidia; de Jesus Hernández-Díaz, Lucio; Canizalez-Roman, Adrian

    2014-01-01

    Vibrio parahaemolyticus is one of the most important seafood-borne bacterial in recent years and is the leading causal agent of human acute gastroenteritis, primarily following the consumption of raw, undercooked or mishandled marine products. Until 1996, infections caused by V. parahaemolyticus were generally associated with diverse serovars. However, in February 1996, a unique serovar (O3:K6) of V. parahaemolyticus with specific genetic markers (tdh, toxRS/New and/or orf8) appeared abruptly in Kolkata, India. In subsequent years, O3:K6 isolates similar to those isolated in Kolkata have been reported from food borne outbreaks in Southeast Asia, as well as in the Atlantic and Gulf coasts of the United States (U.S). More recently, there have been reports in Europe, Africa and Central and South America. Specifically, in the American continent, some countries have reported cases of gastroenteritis due to the pandemic O3:K6 strain and its serovariants; the pandemic strain was first detected in Peru (1996, >100 cases), subsequently spreading to Chile in 1998 (>16,804 human cases), to the U.S. in 1998 (>700 cases), to Brazil in 2001 (>18 cases) and to Mexico in 2004 (>1200 cases). The arrival of the pandemic clone on the American continent may have resulted in a significant shift on the epidemic dynamics of V. parahaemolyticus. However, although O3:K6 is the predominant serovar of the recognized clinical strains in some countries in the Americas, a decrease in clinical cases caused by O3:K6 and an increase in cases associated with a new serotype (O3:K59, Chile) have been recently reported. The emergence and worldwide dissemination of O3:K6 and other pandemic strains since 1996 have come to represent a threat to public health and should concern health authorities. This review focuses on the presence, distribution and virulence factors of the V. parahaemolyticus O3:K6 pandemic clone and its serovariants in clinical and environmental strains on the American continent. PMID

  13. A decade of aerogeophysical exploration helps unveil the architecture and evolution of the Antarctic continent

    NASA Astrophysics Data System (ADS)

    Ferraccioli, F.

    2012-12-01

    Although Antarctica is a keystone within the Gondwana and Rodinia supercontinents it remains the least understood continent on Earth. A decade of aerogeophysical exploration provides fundamental new insights into crustal architecture, evolution, and processes that shaped the Antarctic continent. In western Dronning Maud, aeromagnetic data delineate the Jurassic Jutulstraumen rift that heralded break up between East Antarctica and South Africa. Along the rift flanks remnants of a Grenvillian-age (ca 1.1. Ga) igneous province and magmatic arc are recognised (Ferraccioli et al., 2005, EPS). In the interior of East Antarctica, a mosaic of Precambrian provinces is apparent from aeromagnetic and satellite magnetic data and models of crustal thickness and lithospheric strength (Ferraccioli et al., 2011, Nature). A major suture lies between the Archean Ruker Province and an inferred Meso and Paleoproterozoic Gamburtsev Province. We propose that Grenville-age accretion and collision events linked to Rodinia assembly or older Paleoproteroic events related to the assembly of Nuna/Columbia were responsible for assembling the mosaic of provinces in interior East Antarctica. The inherited mosaic of Precambrian provinces in interior East Antarctica exerts a key influence on the effective elastic thickness of the lithosphere and consequently helps control the location of the newly identified East Antarctic Rift System, which extends for over 3,500 km from India to the Recovery Highlands. Over Wilkes Land, aeromagnetic and aiborne gravity data (Ferraccioli et al., 2009 Tectonophysics; Jordan et al 2012 a, Tectonophysics) offer tantalizing new glimpses into Precambrian basement provinces that were formerly adjacent to Australia. An over 1,900 km long magnetic low is traced from a new magnetic anomaly compilation along the margin of the Archean-Proterozoic Mawson continent, and is interpreted as delineating part of a Neoproterozoic rift system that heralded Rodinia break

  14. A Link Between Reduced Arctic Sea Ice and Cold Winter Extremes over Northern Continents

    NASA Astrophysics Data System (ADS)

    Semenov, V. A.; Petoukhov, V.

    2009-04-01

    The recent overall Northern Hemisphere warming was accompanied by several severe northern continental winters, in particular extremely cold winter 2005/2006 in Europe and northern Asia. Here we show that these cold extremes might be favored by anomalous sea ice reduction in the Barents and Kara Seas in the Eastern Arctic. Atmospheric general circulation model simulations demonstrate that strong anti-cyclonic circulation over the Polar Ocean and easterly advection over northern continents may arise as a response to anomalous atmospheric heating. This brings about a continental-scale winter cooling reaching 1.5˚C, with more than three times increased probability of cold winter extremes. Our results imply that several recent harsh winters do not conflict the global warming picture but rather supplement it, being in agreement with the large-scale atmospheric circulation response to Arctic sea ice reduction.

  15. The peopling of the African continent and the diaspora into the new world

    PubMed Central

    Campbell, Michael C; Hirbo, Jibril B; Townsend, Jeffrey P; Tishkoff, Sarah A

    2014-01-01

    Africa is the birthplace of anatomically modern humans, and is the geographic origin of human migration across the globe within the last 100,000 years. The history of African populations has consisted of a number of demographic events that have influenced patterns of genetic and phenotypic variation across the continent. With the increasing amount of genomic data and corresponding developments in computational methods, researchers are able to explore long-standing evolutionary questions, expanding our understanding of human history within and outside of Africa. This review will summarize some of the recent findings regarding African demographic history, including the African Diaspora, and will briefly explore their implications for disease susceptibility in populations of African descent. PMID:25461616

  16. Consistent response of bird populations to climate change on two continents.

    PubMed

    Stephens, Philip A; Mason, Lucy R; Green, Rhys E; Gregory, Richard D; Sauer, John R; Alison, Jamie; Aunins, Ainars; Brotons, Lluís; Butchart, Stuart H M; Campedelli, Tommaso; Chodkiewicz, Tomasz; Chylarecki, Przemysław; Crowe, Olivia; Elts, Jaanus; Escandell, Virginia; Foppen, Ruud P B; Heldbjerg, Henning; Herrando, Sergi; Husby, Magne; Jiguet, Frédéric; Lehikoinen, Aleksi; Lindström, Åke; Noble, David G; Paquet, Jean-Yves; Reif, Jiri; Sattler, Thomas; Szép, Tibor; Teufelbauer, Norbert; Trautmann, Sven; van Strien, Arco J; van Turnhout, Chris A M; Vorisek, Petr; Willis, Stephen G

    2016-04-01

    Global climate change is a major threat to biodiversity. Large-scale analyses have generally focused on the impacts of climate change on the geographic ranges of species and on phenology, the timing of ecological phenomena. We used long-term monitoring of the abundance of breeding birds across Europe and the United States to produce, for both regions, composite population indices for two groups of species: those for which climate suitability has been either improving or declining since 1980. The ratio of these composite indices, the climate impact indicator (CII), reflects the divergent fates of species favored or disadvantaged by climate change. The trend in CII is positive and similar in the two regions. On both continents, interspecific and spatial variation in population abundance trends are well predicted by climate suitability trends. PMID:27034371

  17. Contribution of the maritime continent convection during the preconditioning stage of the Madden-Julian Oscillation

    NASA Astrophysics Data System (ADS)

    Kubota, H.; Yoneyama, K.; Nasuno, T.; Hamada, J.

    2013-12-01

    During the international field experiment 'Cooperative Indian Ocean experiment on intraseasonal variability in the Year 2011 (CINDY2011)', the preconditioning process of the MJO was observed. In this study, the contribution of the maritime continent convection was focused on the preconditioning process of the third MJO. During the preconditioning stage of the MJO, westward propagating disturbances were observed from Sumatera Island to the central Indian Ocean and moistened the atmosphere. Convections over the Sumatera Island were activated around December 15th when the moist air mass reached from South China Sea. The origin of the moist air mass was tropical cyclone which was formed in South China Sea in December 10th. The high moisture associated with tropical cyclone activated the convection over Sumatera Island, promoted westward propagating disturbances, and acted a favorable environment for the preconditioning of the MJO. This preconditioning stage of the MJO is simulated by Nonhydrostatic ICosahedral Atmospheric Model (NICAM) and investigated the moistening process.

  18. Global change research for protecting resources in the Crown of the continent Ecosystem

    SciTech Connect

    Fagre, D.B. )

    1993-06-01

    A multi-faceted, long-term research program has been initiated by the National Park Service to evaluate the potential effects of climatic changes on natural resources of parks. Glacier National Park is centrally located in a mountainous wilderness complex along the continental divide which was described early in the century as the [open quotes]Crown of the Continent[close quotes]. A central component of the program is a regional ecosystem simulation system. This system acts as an interface for a number of ecological models which collectively provide spatially explicit, mechanistically-derived predictions of microclimate, hydrological output, and forest biophysical processes within the park. Validation of the system is being carried out over the next 5 years with associated studies on glacier dynamics, stream hydrology, lake chemistry, forest landscape classification, remote sensing, and others.

  19. Crustal volumes of the continents and of oceanic and continental submarine plateaus

    NASA Technical Reports Server (NTRS)

    Schubert, G.; Sandwell, D.

    1989-01-01

    Using global topographic data and the assumption of Airy isostasy, it is estimated that the crustal volume of the continents is 7182 X 10 to the 6th cu km. The crustal volumes of the oceanic and continental submarine plateaus are calculated at 369 X 10 to the 6th cu km and 242 X 10 to the 6th cu km, respectively. The total continental crustal volume is found to be 7581 X 10 to the 6th cu km, 3.2 percent of which is comprised of continental submarine plateaus on the seafloor. An upper bound on the contintental crust addition rate by the accretion of oceanic plateaus is set at 3.7 cu km/yr. Subduction of continental submarine plateaus with the oceanic lithosphere on a 100 Myr time scale yields an upper bound to the continental crustal subtraction rate of 2.4 cu km/yr.

  20. The peopling of the African continent and the diaspora into the new world.

    PubMed

    Campbell, Michael C; Hirbo, Jibril B; Townsend, Jeffrey P; Tishkoff, Sarah A

    2014-12-01

    Africa is the birthplace of anatomically modern humans, and is the geographic origin of human migration across the globe within the last 100,000 years. The history of African populations has consisted of a number of demographic events that have influenced patterns of genetic and phenotypic variation across the continent. With the increasing amount of genomic data and corresponding developments in computational methods, researchers are able to explore long-standing evolutionary questions, expanding our understanding of human history within and outside of Africa. This review will summarize some of the recent findings regarding African demographic history, including the African Diaspora, and will briefly explore their implications for disease susceptibility in populations of African descent. PMID:25461616

  1. Consistent response of bird populations to climate change on two continents

    USGS Publications Warehouse

    Stephens, Philip A.; Mason, Lucy R.; Green, Rhys E.; Gregory, Richard D.; Sauer, John R.; Alison, Jamie; Aunins, Ainars; Brotons, Lluís; Butchart, Stuart H.M.; Campedelli, Tommaso; Chodkiewicz, Tomasz; Chylarecki, Przemyslaw; Crowe, Olivia; Elts, Jaanus; Escandell, Virginia; Foppen, Ruud P.B.; Heldbjerg, Henning; Herrando, Sergi; Husby, Magne; Jiguet, Frédéric; Lehikoinen, Aleksi; Lindström, Åke; Noble, David G.; Paquet, Jean-Yves; Reif, Jiri; Sattler, Thomas; Szép, Tibor; Teufelbauer, Norbert; Trautmann, Sven; Van Strien, Arco; van Turnhout, Chris A.M.; Vorisek, Petr; Willis, Stephen G.

    2016-01-01

    Global climate change is a major threat to biodiversity. Large-scale analyses have generally focused on the impacts of climate change on the geographic ranges of species and on phenology, the timing of ecological phenomena. We used long-term monitoring of the abundance of breeding birds across Europe and the United States to produce, for both regions, composite population indices for two groups of species: those for which climate suitability has been either improving or declining since 1980. The ratio of these composite indices, the climate impact indicator (CII), reflects the divergent fates of species favored or disadvantaged by climate change. The trend in CII is positive and similar in the two regions. On both continents, interspecific and spatial variation in population abundance trends are well predicted by climate suitability trends.

  2. A complex empirical orthogonal function for combining two different variables over Indonesian maritime continent

    NASA Astrophysics Data System (ADS)

    Nuryanto, Danang Eko

    2016-02-01

    The spatiotemporal patterns of Indonesian Maritime Continent (IMC) convective activity was documented by using two different variables i.e. cloud and wind datasets. In this study, a Complex Empirical Orthogonal Function (CEOF) was used to combining that variables. This method was applied to representing the land-sea-atmosphere interaction of diurnal convective activity in IMC. This study used pseudo-vector to define complex signals from convective index (cloud) as complex part and convergence (wind) as real part. The results showed that the phase patterns of CEOF were more consistent than those of pseudo-vector. Both CEOF1 and CEOF2 have shown semi-annual and annual cycles, respectively. Spatially, CEOF1 represents common patterns, whereas CEOF2 was more toward local patterns and tends to be in random.

  3. The changing role of mammal life histories in Late Quaternary extinction vulnerability on continents and islands.

    PubMed

    Lyons, S Kathleen; Miller, Joshua H; Fraser, Danielle; Smith, Felisa A; Boyer, Alison; Lindsey, Emily; Mychajliw, Alexis M

    2016-06-01

    Understanding extinction drivers in a human-dominated world is necessary to preserve biodiversity. We provide an overview of Quaternary extinctions and compare mammalian extinction events on continents and islands after human arrival in system-specific prehistoric and historic contexts. We highlight the role of body size and life-history traits in these extinctions. We find a significant size-bias except for extinctions on small islands in historic times. Using phylogenetic regression and classification trees, we find that while life-history traits are poor predictors of historic extinctions, those associated with difficulty in responding quickly to perturbations, such as small litter size, are good predictors of prehistoric extinctions. Our results are consistent with the idea that prehistoric and historic extinctions form a single continuing event with the same likely primary driver, humans, but the diversity of impacts and affected faunas is much greater in historic extinctions. PMID:27330176

  4. Multiple broadly synchronous km-scale exhumation episodes on different continents: implications for controlling processes

    NASA Astrophysics Data System (ADS)

    Green, Paul; Duddy, Ian; Japsen, Peter

    2015-04-01

    Numerous low temperature thermochronology studies have defined regional cooling episodes which imply removal of several km of section over areas of several 104 km2. The origin of such events has long been the subject of debate, while their reality has sometimes been questioned because of the lack of a viable mechanism. Kilometre-scale denudation at rifted margins has traditionally been interpreted as related to rifting and breakup, magnified by the flexural response to denudation of the uplifted rift flanks. But it is now clear that at many margins the post-breakup history is more complex, with km-scale uplift and erosion commonly post-dating breakup by 10s of Myr and often affecting regions many 100s of kilometres inland of the margins (Green et al., 2013; Brown et al., 2014). Numerous examples around the world of km-scale exhumation affecting regions distant from continental margins, including cratonic regions traditionally regarded as stable over Phanerozoic time (e.g. Ault et al., 2009; Flowers & Kelley, 2011), cannot be explained by margin-related mechanisms. It has also become clear that periods of exhumation are separated by episodes of burial, defining a series of positive and negative vertical movements. Previous studies have defined a broad synchroneity of Early, Middle and Late Cenozoic exhumation events in regions from Alaska to Greenland, Norway and Svalbard (Green and Duddy, 2010). New results from SE Australia define a series of exhumation episodes ranging in time from Carboniferous to Cenozoic which are broadly synchronous with similar events previously defined in Brazil and South Africa (Green et al. 2013). While estimates of the timing of exhumation in different areas are subject to some uncertainty, data across three southern hemisphere continents show a broad synchronicity in similar fashion to the northern hemisphere examples cited above. Dynamic topography has been invoked as a possible mechanism for producing uplift, the effects of which

  5. [Hypotheses on the origin of certain parasites on the Latin American continent].

    PubMed

    Nozais, J P

    1985-01-01

    The South American continent has been connected to Africa over millions of centuries. In prehistorical time, the filling of the Bering strait allowed passage on firm ground between Asia and North America. South American peopling has thus occurred from North America, through the Pacific sea and, from the 15th century A.C., through the Atlantic. Necator americanus was present in South America prior to the arrival of black slaves and its African origin is probably related to contacts between Africa and South America; the same applies to Leishmania donovani and Biom-Phalaria glabrata. Ankylostoma duodenale originates from Asia as well as Plasmodium falciparum which was brought by man at time of his migration. To the contrary, muco-cutaneous Leishmaniasis stem (or have a South American origin) from South America. Finally, it is difficult to understand for which reasons Loa loa has not established itself in South America as did Schistosoma mansoni. PMID:3928184

  6. Hierarchical Genetic Analysis of German Cockroach (Blattella germanica) Populations from within Buildings to across Continents

    PubMed Central

    Vargo, Edward L.; Crissman, Jonathan R.; Booth, Warren; Santangelo, Richard G.; Mukha, Dmitry V.; Schal, Coby

    2014-01-01

    Understanding the population structure of species that disperse primarily by human transport is essential to predicting and controlling human-mediated spread of invasive species. The German cockroach (Blattella germanica) is a widespread urban invader that can actively disperse within buildings but is spread solely by human-mediated dispersal over longer distances; however, its population structure is poorly understood. Using microsatellite markers we investigated population structure at several spatial scales, from populations within single apartment buildings to populations from several cities across the U.S. and Eurasia. Both traditional measures of genetic differentiation and Bayesian clustering methods revealed increasing levels of genetic differentiation at greater geographic scales. Our results are consistent with active dispersal of cockroaches largely limited to movement within a building. Their low levels of genetic differentiation, yet limited active spread between buildings, suggests a greater likelihood of human-mediated dispersal at more local scales (within a city) than at larger spatial scales (within and between continents). About half the populations from across the U.S. clustered together with other U.S. populations, and isolation by distance was evident across the U.S. Levels of genetic differentiation among Eurasian cities were greater than those in the U.S. and greater than those between the U.S. and Eurasia, but no clear pattern of structure at the continent level was detected. MtDNA sequence variation was low and failed to reveal any geographical structure. The weak genetic structure detected here is likely due to a combination of historical admixture among populations and periodic population bottlenecks and founder events, but more extensive studies are needed to determine whether signatures of global movement may be present in this species. PMID:25020136

  7. Petroleum potential of lower and middle Paleozoic rocks in Nebraska portion of Mid-Continent

    SciTech Connect

    Carlson, M.P. )

    1989-08-01

    Central North America during the Paleozoic was characterized by northern (Williston) and southern (Anadarko) depositional regimes separated by a stable Transcontinental arch. Nebraska lies on the southern flank of this arch and contains the northern zero edges of the lower and middle Paleozoic rocks of the southern regime. Most of these rocks are secondary dolomites with zones of excellent intercrystalline porosity. The Reagan-LaMotte Sandstones and the overlying Arbuckle dolomites are overlapped by Middle Ordovician rocks toward the Transcontinental arch. Rocks equivalent to the Simpson consist of a basal sand (St. Peter) and overlying interbedded gray-green shales and dolomitic limestones. An uppermost shale facies is present in the Upper Ordovician (Viola-Maquoketa) eastward and southward across Nebraska. The dolomite facies extends northward into the Williston basin. The Silurian dolomites, originally more widely deposited, are overlapped by Devonian dolomites in southeastern Nebraska. Upper Devonian rocks exhibit a regional facies change from carbonate to green-gray shale to black shale southeastward across the Mid-Continent. Mississippian carbonates overlap the Devonian westward and northward across the Transcontinental arch. Pennsylvanian uplift and erosion were widespread, producing numerous stratigraphic traps. Sands related to the basal Pennsylvanian unconformity produce along the Cambridge arch. Arbuckle, Simpson, Viola, and Hunton production is present in the Forest City basin and along the Central Kansas uplift. Although source rocks are scarce and the maturation is marginal, current theories of long-distance oil migration encourage exploration in the extensive lower and middle Paleozoic reservoirs in this portion of the Mid-Continent.

  8. Assessing Microseismicity of the Northern Mid-Continent Rift Zone and Surrounding Regions

    NASA Astrophysics Data System (ADS)

    Bartz, D.; Wysession, M. E.; Wiens, D. A.; Aleqabi, G. I.; Shore, P.; van der Lee, S.; Jurdy, D. M.; Stein, S. A.; Revenaugh, J.; Wolin, E.; Bollmann, T. A.; Frederiksen, A. W.; Darbyshire, F. A.

    2014-12-01

    SPREE is a flexible array (FA) deployment associated with the EarthScope project with the aim of better understanding the Mid-Continent Rift Zone (MCRZ). We have used data from SPREE FA and TA stations to detect and locate small earthquakes in the vicinity of the northwestern arm of the Mid-Continent Rift Zone, covering Minnesota, Wisconsin, and parts of Iowa, Michigan, and Ontario. This region, now stable craton, is a failed Precambrian rift marked by low levels of recorded seismicity, perhaps resulting in part from a historic dearth of stations deployed in the region. We assessed this possibility by taking advantage of the densest array that has been deployed in the region. Processing has allowed for regional stress constraints and a means of distinguishing earthquakes from mine blasts, and a quantitative method to differentiate natural earthquakes from mine blasting events, frequent here. After automated event identification, a manual review confirmed 14 earthquakes and several hundred blasting events with magnitudes ranging from M1 - M3. Observed seismicity is in reasonable agreement with available historical data. We use these earthquakes in conjunction with historical catalogs to estimate regional recurrence intervals for events of greater magnitudes. While initial earthquake/blast discrimination was done manually, the ratio of Rayleigh to P-wave amplitude appears to be a reliable discriminant for distinguishing between earthquakes and mine blasting in this region in a systematic way, with earthquakes displaying a systematically depressed ratio. Additionally, P-wave first-motion data and S/P amplitude ratios from natural events constrain focal mechanisms and regional stresses. These methods indicate roughly WSW-ENE compression, consistent with other determinations and absolute plate motion. The majority of events detected lie some distance from the actual rift; we thus conclude current seismicity bears no preferred association with the MCR.

  9. The connectivity of Mytilus galloprovincialis in northern Morocco: A gene flow crossroads between continents

    NASA Astrophysics Data System (ADS)

    Ouagajjou, Yassine; Presa, Pablo

    2015-01-01

    Previous population genetic studies on the Mediterranean mussel Mytilus galloprovincialis have shown the existence of two well differentiated sets of populations around Southern European coasts, one Atlantic and another Mediterranean. Those two population pools are kept apart by the Almería - Oran Oceanographic Front (AOOF), an oceanographic discontinuity acting either as a cause of such differentiation or simply as a means of maintaining two historically differentiated gene pools. The role of the Gibraltar Strait at shaping mussel larval flow entering the Alboran Sea has been much less addressed, especially regarding mussel swarms inhabiting the northern coast of Morocco. The present study applies seven microsatellite markers to describing the genetic status of northern Moroccan populations of M. galloprovincialis and their relationship with the two well-characterized mussel gene pools from southern Europe. We show that the Atlantic Iberia gene pool extending continuously from the Cantabrian Sea (NE Iberia) to the Alboran Sea (SE Iberia) up to the AOOF is well differentiated from the Atlantic Moroccan mussel. Either an oceanographic barrier or a limited larval dispersal or both, are required to explain this unexpected intercontinental differentiation regarding previous studies on this species. Populations from Atlantic Morocco conformed to a single gene pool (FST ± SD = 0.012 ± 0.007) as opposed to the reported latitudinal barrier to gene flow at Cape Ghir in western Morocco. Additionally, a significant restriction to gene flow was observed between Atlantic Morocco and Alboran Morocco (FST ± SD = 0.038 ± 0.010) in contrast to the reported mussel genetic continuity along the Iberian coast up to AOOF. Three major mussel gene pools appear to meet at this crossroads between continents and between seas, namely, a Mediterranean European subpopulation, an Atlantic Iberia subpopulation including the Alboran Sea, and an Atlantic Morocco subpopulation. Knowledge on

  10. Hierarchical genetic analysis of German cockroach (Blattella germanica) populations from within buildings to across continents.

    PubMed

    Vargo, Edward L; Crissman, Jonathan R; Booth, Warren; Santangelo, Richard G; Mukha, Dmitry V; Schal, Coby

    2014-01-01

    Understanding the population structure of species that disperse primarily by human transport is essential to predicting and controlling human-mediated spread of invasive species. The German cockroach (Blattella germanica) is a widespread urban invader that can actively disperse within buildings but is spread solely by human-mediated dispersal over longer distances; however, its population structure is poorly understood. Using microsatellite markers we investigated population structure at several spatial scales, from populations within single apartment buildings to populations from several cities across the U.S. and Eurasia. Both traditional measures of genetic differentiation and Bayesian clustering methods revealed increasing levels of genetic differentiation at greater geographic scales. Our results are consistent with active dispersal of cockroaches largely limited to movement within a building. Their low levels of genetic differentiation, yet limited active spread between buildings, suggests a greater likelihood of human-mediated dispersal at more local scales (within a city) than at larger spatial scales (within and between continents). About half the populations from across the U.S. clustered together with other U.S. populations, and isolation by distance was evident across the U.S. Levels of genetic differentiation among Eurasian cities were greater than those in the U.S. and greater than those between the U.S. and Eurasia, but no clear pattern of structure at the continent level was detected. MtDNA sequence variation was low and failed to reveal any geographical structure. The weak genetic structure detected here is likely due to a combination of historical admixture among populations and periodic population bottlenecks and founder events, but more extensive studies are needed to determine whether signatures of global movement may be present in this species. PMID:25020136

  11. Continent-wide risk assessment for the establishment of nonindigenous species in Antarctica.

    PubMed

    Chown, Steven L; Huiskes, Ad H L; Gremmen, Niek J M; Lee, Jennifer E; Terauds, Aleks; Crosbie, Kim; Frenot, Yves; Hughes, Kevin A; Imura, Satoshi; Kiefer, Kate; Lebouvier, Marc; Raymond, Ben; Tsujimoto, Megumu; Ware, Chris; Van de Vijver, Bart; Bergstrom, Dana Michelle

    2012-03-27

    Invasive alien species are among the primary causes of biodiversity change globally, with the risks thereof broadly understood for most regions of the world. They are similarly thought to be among the most significant conservation threats to Antarctica, especially as climate change proceeds in the region. However, no comprehensive, continent-wide evaluation of the risks to Antarctica posed by such species has been undertaken. Here we do so by sampling, identifying, and mapping the vascular plant propagules carried by all categories of visitors to Antarctica during the International Polar Year's first season (2007-2008) and assessing propagule establishment likelihood based on their identity and origins and on spatial variation in Antarctica's climate. For an evaluation of the situation in 2100, we use modeled climates based on the Intergovernmental Panel on Climate Change's Special Report on Emissions Scenarios Scenario A1B [Nakićenović N, Swart R, eds (2000) Special Report on Emissions Scenarios: A Special Report of Working Group III of the Intergovernmental Panel on Climate Change (Cambridge University Press, Cambridge, UK)]. Visitors carrying seeds average 9.5 seeds per person, although as vectors, scientists carry greater propagule loads than tourists. Annual tourist numbers (∼33,054) are higher than those of scientists (∼7,085), thus tempering these differences in propagule load. Alien species establishment is currently most likely for the Western Antarctic Peninsula. Recent founder populations of several alien species in this area corroborate these findings. With climate change, risks will grow in the Antarctic Peninsula, Ross Sea, and East Antarctic coastal regions. Our evidence-based assessment demonstrates which parts of Antarctica are at growing risk from alien species that may become invasive and provides the means to mitigate this threat now and into the future as the continent's climate changes. PMID:22393003

  12. Malone antegrade continence enema (MACE) for fecal incontinence in imperforate anus improves quality of life.

    PubMed

    Mattix, Kelly D; Novotny, Nathan M; Shelley, Anita A; Rescorla, Frederick J

    2007-12-01

    The MACE procedure has been used in patients with imperforate anus (IA) to improve fecal continence. Our aim was to assess the impact of the MACE on the quality of life (QOL) in children with IA and fecal incontinence. A retrospective review was performed of children with IA that underwent the MACE procedure between 1997 and 2004. Patients and their parents were contacted by telephone survey regarding continence and its psychosocial effects before and after MACE. The same survey was given to the patients' teachers. Responses to 15 questions were compiled and a QOL score calculated and significance evaluated by t-test (P < or = 0.05). IRB approval was obtained. Thirty-two patients were identified with a mean age at operation of 9 years (4-19 years) and mean follow-up of 3.8 years (7 months to 8 years). Four patients had a low malformation, 8 were intermediate, 15 were high, and 5 had a cloacal anomaly. Twenty patients had documented sacral/spinal anomalies, including five with tethered cord. Post-MACE complications included stenosis in 16 (50%), with 11 requiring an operative revision at a mean of 21.7 months (2 months to 6 years), takedown in one at 4 years and volvulus in one at 18 months. Prior to the MACE, 18/25 (72%) had poor QOL scores. Post-MACE QOL results were similar between patients, parents and teachers. Patients' mean QOL score improved from 59.9 to 26.3% (P < 0.001), with parents from 59.7 to 26.4% (P < 0.001). QOL score improved >50% in nine families, 25-50% in ten and <25% in six. All patients and parents interviewed reported an improvement in their QOL following the MACE. This procedure should be offered to children with IA with the expectation of significant improvement in QOL. PMID:17938937

  13. Continent-wide risk assessment for the establishment of nonindigenous species in Antarctica

    PubMed Central

    Chown, Steven L.; Huiskes, Ad H. L.; Gremmen, Niek J. M.; Lee, Jennifer E.; Terauds, Aleks; Crosbie, Kim; Frenot, Yves; Hughes, Kevin A.; Imura, Satoshi; Kiefer, Kate; Lebouvier, Marc; Raymond, Ben; Tsujimoto, Megumu; Ware, Chris; Van de Vijver, Bart; Bergstrom, Dana Michelle

    2012-01-01

    Invasive alien species are among the primary causes of biodiversity change globally, with the risks thereof broadly understood for most regions of the world. They are similarly thought to be among the most significant conservation threats to Antarctica, especially as climate change proceeds in the region. However, no comprehensive, continent-wide evaluation of the risks to Antarctica posed by such species has been undertaken. Here we do so by sampling, identifying, and mapping the vascular plant propagules carried by all categories of visitors to Antarctica during the International Polar Year's first season (2007–2008) and assessing propagule establishment likelihood based on their identity and origins and on spatial variation in Antarctica's climate. For an evaluation of the situation in 2100, we use modeled climates based on the Intergovernmental Panel on Climate Change's Special Report on Emissions Scenarios Scenario A1B [Nakićenović N, Swart R, eds (2000) Special Report on Emissions Scenarios: A Special Report of Working Group III of the Intergovernmental Panel on Climate Change (Cambridge University Press, Cambridge, UK)]. Visitors carrying seeds average 9.5 seeds per person, although as vectors, scientists carry greater propagule loads than tourists. Annual tourist numbers (∼33,054) are higher than those of scientists (∼7,085), thus tempering these differences in propagule load. Alien species establishment is currently most likely for the Western Antarctic Peninsula. Recent founder populations of several alien species in this area corroborate these findings. With climate change, risks will grow in the Antarctic Peninsula, Ross Sea, and East Antarctic coastal regions. Our evidence-based assessment demonstrates which parts of Antarctica are at growing risk from alien species that may become invasive and provides the means to mitigate this threat now and into the future as the continent's climate changes. PMID:22393003

  14. Seismic investigation of an ocean-continent transition zone in the northern South China Sea

    NASA Astrophysics Data System (ADS)

    Zhu, J.; Qiu, X.; Xu, H.; Zhan, W.; Sun, Z.

    2011-12-01

    Rifted continental margins and basins are mainly formed by the lithospheric extension. Thined lithosphere of passive continental margins results in decompression melt of magma and created oceanic crust and thined ocean-continent transition (OCT) zone. Two refraction profiles used ocean bottom seismometers deployed in the broad continental shelf and three multi-channel seismic reflection lines in the northern South China Sea, acquired by the ship "Shiyan 2" of the South China Sea Institute of Oceanology, Chinese Academy of Sciences in 2010, are processed and interpreted in this study. Seismic reflection lines cut through the Dongsha rise, Zhu-1 and Zhu-2 depression within a Tertiary basin, Pear River Mouth basin (called as Zhujiangkou basin). These tectonic features are clear imaged in the seismic reflection records. Numerous normal faults, cutted through the basement and related to the stretch of the northern South China Sea margin, are imaged and interpreted. Reflection characteristics of the ocean-continent transition (OCT) zone are summaried and outlined. The COT zone is mainly divided into the northern syn-rift subsidence zone, central volcano or buried volcano uplift zone and tilt faulted block near the South Chia Sea basin. Compared to the previous seismic reflection data and refraction velocity models, the segmentation range of the OCT zone is outlined, from width of about 225 km in the northeastern South China Sea , of 160 km in the central to of 110 km in the north-central South China Sea. Based on the epicenter distribution of sporadic and large than 6 magnitude earthquakes, it suggests the OCT zone in the northern South China Sea at present is still an active seismic zone.

  15. Exploration of tectonic structures with GOCE in Africa and across-continents

    NASA Astrophysics Data System (ADS)

    Braitenberg, Carla

    2015-03-01

    The gravity anomaly field over the whole Earth obtained by the GOCE satellite is a revolutionary tool to reveal geologic information on a continental scale for the large areas where conventional gravity measurements have yet to be made. It is, however, necessary to isolate the near-surface geologic signal from the contributions of thickness variations in the crust and lithosphere and the isostatic compensation of surface relief. Here Africa is studied with particular emphasis on selected geological features which are expected to appear as density inhomogeneities. These include cratons and fold belts in the Precambrian basement, the overlying sedimentary basins and magmatism, as well as the continental margins. Regression analysis between gravity and topography shows coefficients that are consistently positive for the free air gravity anomaly and negative for the Bouguer gravity anomaly. The error and scatter on the regression are smallest in oceanic areas, where it is a possible tool for identifying changes in crustal type. The regression analysis allows the large gradient in the Bouguer anomaly signal across continental margins to be removed. After subtracting the predicted effect of known topography from the original Bouguer anomaly field, the residual field shows a continent-wide pattern of anomalies that could be attributed to regional geological structures. A few of these are highlighted, such as those representing Karoo magmatism, the Kibalian foldbelt, the Zimbabwe Craton, the Cameroon and Tibesti volcanic deposits, the Benue Trough and the Luangwa Rift. A reconstruction of the pre-break up position of Africa and South America (the plates forming West Gondwana) is made for the residual GOCE gravity field. The reconstruction allows the positive and negative anomalies to be compared across the continental fragments, and so helps identify common geologic units that extend across both the now-separate continents.

  16. Patterns of Human Diversity, within and among Continents, Inferred from Biallelic DNA Polymorphisms

    PubMed Central

    Romualdi, Chiara; Balding, David; Nasidze, Ivane S.; Risch, Gregory; Robichaux, Myles; Sherry, Stephen T.; Stoneking, Mark; Batzer, Mark A.; Barbujani, Guido

    2002-01-01

    Previous studies have reported that about 85% of human diversity at Short Tandem Repeat (STR) and Restriction Fragment Length Polymorphism (RFLP) autosomal loci is due to differences between individuals of the same population, whereas differences among continental groups account for only 10% of the overall genetic variance. These findings conflict with popular notions of distinct and relatively homogeneous human races, and may also call into question the apparent usefulness of ethnic classification in, for example, medical diagnostics. Here, we present new data on 21 Alu insertions in 32 populations. We analyze these data along with three other large, globally dispersed data sets consisting of apparently neutral biallelic nuclear markers, as well as with a β-globin data set possibly subject to selection. We confirm the previous results for the autosomal data, and find a higher diversity among continents for Y-chromosome loci. We also extend the analyses to address two questions: (1) whether differences between continental groups, although small, are nevertheless large enough to confidently assign individuals to their continent on the basis of their genotypes; (2) whether the observed genotypes naturally cluster into continental or population groups when the sample source location is ignored. Using a range of statistical methods, we show that classification errors are at best around 30% for autosomal biallelic polymorphisms and 27% for the Y chromosome. Two data sets suggest the existence of three and four major groups of genotypes worldwide, respectively, and the two groupings are inconsistent. These results suggest that, at random biallelic loci, there is little evidence, if any, of a clear subdivision of humans into biologically defined groups. PMID:11932244

  17. “Total reconstruction” of the urethrovesical anastomosis contributes to early urinary continence in laparoscopic radical prostatectomy

    PubMed Central

    Liao, Xiaoxing; Qiao, Peng; Tan, Zhaohui; Shi, Hongbin; Xing, Nianzeng

    2016-01-01

    ABSTRACT Purpose: To demonstrate the effect of total reconstruction technique on postoperative urinary continence after laparoscopic radical prostatectomy (LRP). Material and Methods: LRP was performed using a standard urethrovesical anastomosis in 79 consecutive patients (Group-A) from June 2011 to October 2012, and a total reconstruction procedure in 82 consecutive patients (Group-B) from June 2012 to June 2013. The primary outcome measurement was urinary continence assessed at 1, 2, 4, 12, 24 and 52 weeks after catheter removal. Other data recorded were patient age, body mass index, International Prostate Symptoms Score, prostate volume, preoperative PSA, Gleason score, neurovascular bundle preservation, operation time, estimated blood loss, complications and pathology results. Results: In Group-A, the continence rates at 1, 2, 4, 12, 24 and 52 weeks were 7.59%, 20.25%, 37.97%, 58.22%, 81.01% and 89.87% respectively. In Group-B, the continence rates were 13.41%, 32.92%, 65.85%, 81.71%, 90.24% and 95.12% respectively. Group––B had significantly higher continence rates at 4 and 12 weeks after surgery (P<0.001 and P=0.001). There were no significant differences between the groups with respect to patient's age, body mass index, prostate-specific antigen level, prostate volume, IPSS, estimated blood loss, number of nerve-sparing procedures and postoperative complications. Conclusions: Total reconstruction technique in the procedure of urethrovesical anastomosis during LRP improved early recovery of continence. PMID:27256174

  18. Warming increases plant biomass and reduces diversity across continents, latitudes, and species migration scenarios in experimental wetland communities.

    PubMed

    Baldwin, Andrew H; Jensen, Kai; Schönfeldt, Marisa

    2014-03-01

    Atmospheric warming may influence plant productivity and diversity and induce poleward migration of species, altering communities across latitudes. Complicating the picture is that communities from different continents deviate in evolutionary histories, which may modify responses to warming and migration. We used experimental wetland plant communities grown from seed banks as model systems to determine whether effects of warming on biomass production and species richness are consistent across continents, latitudes, and migration scenarios. We collected soil samples from each of three tidal freshwater marshes in estuaries at three latitudes (north, middle, south) on the Atlantic coasts of Europe and North America. In one experiment, we exposed soil seed bank communities from each latitude and continent to ambient and elevated (+2.8 °C) temperatures in the greenhouse. In a second experiment, soil samples were mixed either within each estuary (limited migration) or among estuaries from different latitudes in each continent (complete migration). Seed bank communities of these migration scenarios were also exposed to ambient and elevated temperatures and contrasted with a no-migration treatment. In the first experiment, warming overall increased biomass (+16%) and decreased species richness (-14%) across latitudes in Europe and North America. Species richness and evenness of south-latitude communities were less affected by warming than those of middle and north latitudes. In the second experiment, warming also stimulated biomass and lowered species richness. In addition, complete migration led to increased species richness (+60% in North America, + 100% in Europe), but this higher diversity did not translate into increased biomass. Species responded idiosyncratically to warming, but Lythrum salicaria and Bidens sp. increased significantly in response to warming in both continents. These results reveal for the first time consistent impacts of warming on biomass and

  19. A note on the annual cycles of surface heat balance and temperature over a continent. [North America

    NASA Technical Reports Server (NTRS)

    Spar, J.; Crane, G.

    1974-01-01

    A surface heating function, defined as the ratio of the time derivative of the mean annual temperature curve to the surface heat balance, is computed from the annual temperature range and heat balance data for the North American continent. An annual cycle of the surface heat balance is then reconstructed from the surface heating function and the annual temperature curve, and an annual cycle of evaporative plus turbulent heat loss is recomputed from the annual cycles of radiation balance and surface heat balance for the continent. The implications of these results for long range weather forecasting are discussed.

  20. Intermediate crust (IC); its construction at continent edges, distinctive epeirogenic behaviour and identification as sedimentary basins within continents: new light on pre-oceanic plate motions

    NASA Astrophysics Data System (ADS)

    Osmaston, Miles F.

    2014-05-01

    Introduction. The plate tectonics paradigm currently posits that the Earth has only two kinds of crust - continental and oceanic - and that the former may be stretched to form sedimentary basins or the latter may be modified by arc or collision until it looks continental. But global analysis of the dynamics of actual plate motions for the past 150 Ma indicates [1 - 3] that continental tectospheres must be immensely thicker and rheologically stiffer than previously thought; almost certainly too thick to be stretched with the forces available. In the extreme case of cratons, these tectospheric keels evidently extend to 600 km or more [2, 3]. This thick-plate behaviour is attributable, not to cooling but to a petrological 'stiffening' effect, associated with a loss of water-weakening of the mineral crystals, which also applies to the hitherto supposedly mobile LVZ below MORs [4, 5]. The corresponding thick-plate version of the mid-ocean ridge (MOR) process [6 - 8], replacing the divergent mantle flow model, has a deep, narrow wall-accreting axial crack which not only provides the seismic anisotropy beneath the flanks but also brings two outstanding additional benefits:- (i) why, at medium to fast spreading rates, MOR axes become straight and orthogonally segmented [6], (ii) not being driven by body forces, it can achieve the sudden jumps of axis, spreading-rate and direction widely present in the ocean-floor record. Furthermore, as we will illustrate, the crack walls push themselves apart at depth by a thermodynamic mechanism, so the plates are not being pulled apart. So the presence of this process at a continental edge would not imply the application of extensional force to the margin. Intermediate Crust (IC). In seeking to resolve the paradox that superficially extensional structures are often seen at margins we will first consider how this MOR process would be affected by the heavy concurrent sedimentation to be expected when splitting a mature continent. I reason

  1. Tag team tectonics: mantle upwelling and lithospheric heterogeneity ally to rift continents (Invited)

    NASA Astrophysics Data System (ADS)

    Nelson, W. R.; Furman, T.

    2013-12-01

    The configuration of continents we know today is the result of several billion years of active Wilson Cycle tectonics. The rifting of continents and subsequent development of ocean basins is an integral part of long-term planetary-scale recycling processes. The products of this process can be seen globally, and the East African Rift System (EARS) provides a unique view of extensional processes that actively divide a continent. Taken together with the adjoining Red Sea and Gulf of Aden, the EARS has experienced over 40 Ma of volcanism and ~30 Ma of extension. While early (pre-rift) volcanism in the region is attributed to mantle plume activity, much of the subsequent volcanism occurs synchronously with continental rifting. Numerous studies indicate that extension and magmatism are correlated: extension leads to decompression melting while magmatism accommodates further extension (e.g. Stein et al., 1997; Buck 2004; Corti 2012). Evaluation of the entire EARS reveals significant geochemical patterns - both spatial and temporal - in the volcanic products. Compositional variations are tied directly to the melt source(s), which changes over time. These variations can be characterized broadly by region: the Ethiopian plateau and Turkana Depression, the Kenya Rift, and the Western Rift. In the Ethiopian plateau, early flood basalt volcanism is dominated by mantle plume contributions with variable input from lherzolitic mantle lithosphere. Subsequent alkaline shield volcanism flanking the juvenile Main Ethiopian Rift records the same plume component as well as contributions from a hydrous peridotitic lithosphere. The hydrous lithosphere does not contribute indefinitely. Instead, young (< 2 Ma) volcanism taps a combination of the mantle plume and anhydrous depleted lithospheric mantle. In contrast, volcanism in the Kenya Rift and the Western Rift are derived dominantly from metasomatized lithospheric mantle rather than mantle plume material. These rifts lie in the mobile

  2. High-resolution mapping of biomass burning emissions in tropical regions across three continents

    NASA Astrophysics Data System (ADS)

    Shi, Yusheng; Matsunaga, Tsuneo; Saito, Makoto

    2015-04-01

    Biomass burning emissions from open vegetation fires (forest fires, savanna fires, agricultural waste burning), human waste and biofuel combustion contain large amounts of trace gases (e.g., CO2, CH4, and N2O) and aerosols (BC and OC), which significantly impact ecosystem productivity, global atmospheric chemistry, and climate . With the help of recently released satellite products, biomass density based on satellite and ground-based observation data, and spatial variable combustion factors, this study developed a new high-resolution emissions inventory for biomass burning in tropical regions across three continents in 2010. Emissions of trace gases and aerosols from open vegetation burning are estimated from burned areas, fuel loads, combustion factors, and emission factors. Burned areas were derived from MODIS MCD64A1 burned area product, fuel loads were mapped from biomass density data sets for herbaceous and tree-covered land based on satellite and ground-based observation data. To account for spatial heterogeneity in combustion factors, global fractional tree cover (MOD44B) and vegetation cover maps (MCD12Q1) were introduced to estimate the combustion factors in different regions by using their relationship with tree cover under less than 40%, between 40-60% and above 60% conditions. For emission factors, the average values for each fuel type from field measurements are used. In addition to biomass burning from open vegetation fires, the emissions from human waste (residential and dump) burning and biofuel burning in 2010 were also estimated for 76 countries in tropical regions across the three continents and then allocated into each pixel with 1 km grid based on the population density (Gridded Population of the World v3). Our total estimates for the tropical regions across the three continents in 2010 were 17744.5 Tg CO2, 730.3 Tg CO, 32.0 Tg CH4, 31.6 Tg NOx, 119.2 Tg NMOC, 6.3 Tg SO2, 9.8 NH3 Tg, 81.8 Tg PM2.5, 48.0 Tg OC, and 5.7 Tg BC, respectively. Open

  3. SELECTION AND TREATMENT OF STRIPPER GAS WELLS FOR PRODUCTION ENHANCEMENT IN THE MID-CONTINENT

    SciTech Connect

    Scott Reeves

    2003-03-01

    Stripper gas wells are an important source of domestic energy supply and under constant threat of permanent loss (shut-in) due to marginal economics. In 1998, 192 thousand stripper gas wells produced over a Tcf of gas, at an average rate of less than 16 Mcfd. This represents about 57% of all producing gas wells in the onshore lower-48 states, yet only 8% of production. Reserves of stripper gas wells are estimated to be only 1.6 Tcf, or slightly over 1% of the onshore lower-48 total (end of year 1996 data). Obviously, stripper gas wells are at the very margin of economic sustenance. As the demand for natural gas in the U.S. grows to the forecasted estimate of over 30 Tcf annually by the year 2010, supply from current conventional sources is expected to decline. Therefore, an important need exists to fully exploit known domestic resources of natural gas, including those represented by stripper gas wells. The overall objectives of this project are to develop an efficient and low-cost methodology to broadly categorize the well performance characteristics for a stripper gas field, identify the high-potential candidate wells for remediation, and diagnose the specific causes for well underperformance. With this capability, stripper gas well operators can more efficiently and economically produce these resources and maximize these gas reserves. A further objective is to identify/develop, evaluate and test ''new and novel,'' economically viable remediation options. Finally, it is the objective of this project that all the methods and technologies developed in this project, while being tested in the Mid-Continent, be widely applicable to stripper gas wells of all types across the country. The project activities during the reporting period were: (1) Continued to solicit industry research partners to provide test sites. A Cooperative Research Agreement has been signed with Oneok, for a test site in the Mocane-Laverne field in the Anadarko basin (Oklahoma). The site consists of

  4. Globalization and Multilingualism: Case Studies of Indigenous Culture-Based Education from the Indian Sub-Continent and Their Implications

    ERIC Educational Resources Information Center

    Singh, Navin Kumar

    2013-01-01

    This paper presents some of the major program initiatives honoring Indigenous knowledge, culture, heritage, arts, and skills through curricular reforms and culturally appropriate educational practices on the Indian sub-continent. It presents case studies of Indigenous culture-based education, with reference to mother tongue and multicultural…

  5. 77 FR 35959 - Atlas Pipeline Mid-Continent WestTex, LLC; Pioneer Natural Resources USA, Inc.; Notice of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-15

    ... Federal Energy Regulatory Commission Atlas Pipeline Mid-Continent WestTex, LLC; Pioneer Natural Resources...Tex, LLC (Atlas) and Pioneer Natural Resources USA, Inc. (Pioneer), filed in the above referenced docket a joint application pursuant to section 7(c) of the Natural Gas Act (NGA) and Part 157 of...

  6. An Assessment of Stressor Extent and Biological Condition in the North American Mid-continent Great Rivers (USA)

    EPA Science Inventory

    We assessed the North American mid-continent great rivers (Upper Mississippi, Missouri, and Ohio). We estimated the extent of each river in most- (MDC) or least-disturbed condition (LDC) based on multiple biological response indicators: fi sh and macroinvertebrate, trophic stat...

  7. Taking the pulse of a continent: Expanding site-based research infrastructure for regional- to continental-scale ecology

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Many of the most dramatic and surprising effects of global change on ecological systems will occur across large spatial extents, from regions to continents. Multiple ecosystem types will be impacted across a range of interacting spatial and temporal scales. The ability of ecologists to understand an...

  8. Imaging high-pressure rock exhumation along the arc-continent suture in eastern Taiwan

    NASA Astrophysics Data System (ADS)

    Brown, Dennis; Feng, Kuan-Fu; Wu, Yih-Min; Huang, Hsin-Hua

    2015-04-01

    Imaging high-pressure rock exhumation in active tectonic settings is considered to be one of the important observations that could potentially help to move forward the understanding of how this process works. Petrophysical analyses carried out along a high velocity zone imaged by seismic travel time tomography along the suture zone between the actively colliding Luzon Arc and the southeastern margin of Eurasia in Taiwan suggests that high-pressure rocks are being exhumed from at least a depth of 50 km below the arc-continent suture to the shallow subsurface where they coincide with an outcropping tectonic mélange called the Yuli Belt. The Yuli Belt comprises mainly greenschist facies quartz-mica schist, with lesser metabasite, metamorphosed mantle fragments and, importantly, minor blueschist. Modeling of published data bases of measured seismic velocities for a large suite of rocks suggests that all of the Yuli belt lithologies fit well with the measured Vp, Vs, and Vp/Vs at ambient pressures and temperatures (a 20 oC/km geotherm is used) from 10 to about 20 km depth. With the exception of hornblendite, mantle rocks need 30% to 40 % serpentinization to approximate the in situ range of Vp and and Vs at these depths. From about 20 km to 30 km, most continental crust and volcanic arc lithologies move out of the range of velocities measured by the tomography model at these depths. Blueschist (including the calculated Vp and Vs for the Yuli Belt samples), pyroxenite, and harzburgite, lherzolite, and dunite with around 20% to 30% serpentinization now enter into the range of velocities for these depths. From 40 km to 50 km depth, the mantle rocks pyroxenite, and weakly to unserpentinized harzburgite, lherzolite, and dunite, together with mafic eclogite velocities best fit the range of Vp, Vs and Vp/Vs at these depths. Seismicity along the arc-continent suture, the upper bounding fault of the high velocity zone examined here, indicate that it is a moderately oblique

  9. 3D Geometry and Kinematics of the Taiwan Arc-continent Collision

    NASA Astrophysics Data System (ADS)

    Carena, S.; Suppe, J.; Wu, Y. M.

    2015-12-01

    In Taiwan two subduction zones (Manila trench and Ryukyu trench) come together in a quasi-orthogonal, kinematically stable configuration. Subduction is ongoing in both trenches, even though the tectonic setting in the Manila trench is that of an arc-continent collision. The upper crust of Eurasia (EU) is decoupled from the rest of the lithosphere by a detachment horizon, which is the main subduction interface between EU and Philippine Sea plate (PSP). The interface is visible in both seismicity and crustal tomography at shallow depths, and it can be followed into the mantle to 450-500 km depth with global tomography. Shortening across the plate boundary is accomplished by a combination of subduction of EU lithosphere, folding and thrusting in the Eurasian upper crust, and a secondary subduction zone within the PSP. We hypothesize that: (1) once arc-continent collision occurs, subduction of Eurasian continental lower crust and upper mantle can continue by lithospheric delamination and by continuity with the much larger Eurasian slab to the south; (2) the upper crust of EU deforms by faulting and folding; (3) the present convergence rate of about 90 mm/yr is limited at most to the last 2 Ma, whereas the long-term rate is about 30 mm/yr and in Taiwan the difference is being taken up by secondary subduction within the PSP margin; (4) a margin-parallel STEP (Subduction-Transform-Edge-Propagator) fault forms the northern limit of Eurasian subduction, which allows the whole system to propagate self-similarly southwestward. No slab breakoff is required for the kinematics of the margin, and none is observed in geophysical or geological data either. This kinematics is consistent with geologic observations: from timing of opening of the southern Okinawa trough, to geometry of geologic boundaries within the Taiwan mountain belt, to geographic distribution, geochemical character, and timing of Quaternary volcanism in the northern Taiwan volcanic zone. We constrained the long

  10. Moho depth variations beneath China continent from deep seismic sounding profiling

    NASA Astrophysics Data System (ADS)

    Teng, Jiwen; Zhang, Zhongjie; Zhang, Yongqian; Pi, Jiaolong; Deng, Yangfan; Zhang, Xiankang; Wang, Chunyong; Gao, Rui; Liu, Cai

    2013-04-01

    Knowledge of Moho depth and crustal structure are required to study and explore the deep process and coupling response of the formation of mountains, basins, rocks and disasters. In the past half century, the geophysicists in China have completed more than 130 seismic refraction and wide-angle reflection profiles with a total length of 60000km and 11 global geosciences transections (GGT) in China. In this study, we aim to make a systematic research into the Moho depth and crustal structure in China based on the data of velocity models of the crust and upper mantle derived from these more than 130 wide-angle seismic profiles acquired in the last 50 years in China and the surrounding areas. With advanced interpolation technique, we obtain Moho map and average P-wave velocity model, and then make the study on the variations in Moho depth and crustal structure in different tectonics in the East Asia. According to our research results, the resultant Moho depth ranges within 10 and 80 km, and is featured with the deepest Moho discontinuity of about 70-85km beneath Tibetan plateau formed by ongoing continent-continent collision; and relatively constant 30-35 km beneath the eastern North China craton enduring destruction of Lithosphere destruction. Also, we analyzed the average crustal thickness of the consolidated crust beneath the three cratons in China, which is characterized by a gradual thickening from east to west with the values of 29~47 km beneath North-China craton (east), 30~56 km beneath Yangtze craton (south) and 42~59 km beneath Tarim craton (west). In addition, there are three major fold tectonic units in the continental domain and the adjacent oceanic areas, namely the Tethyan-Himalayan zone (south and west), the Paleo-Asian zone (northwest and northeast) and the Circum-Pacific zone (east), which in turn are subdivided into 15 orogenic zones. The Moho depth in these 15 orogenic zones is quite different, too.

  11. Intraseasonal Variability of δ18O of Precipitation in The Indonesia Maritime Continent

    NASA Astrophysics Data System (ADS)

    Belgaman, H. A.; Ichiyanagi, K.; Tanoue, M.; Suwarman, R.; Yoshimura, K.; Mori, S.; Yamanaka, M. D.; Kurita, N.; Syamsudin, F.

    2014-12-01

    The Indonesian maritime continent (IMC) consists of many islands in a warm pool of sea water and is located between two great oceans—the Pacific Ocean and Indian Ocean, and two major continents—the Asian and Australian continents. This tropical region also influenced by many regional and local climate and weather phenomenon which causes high spatial and temporal rainfall variability. These factors may produce unique variability of isotopic precipitation. The isotopic content (d18O and dD) in precipitation have been known to have important role for reconstructing the atmospheric circulation, hydrological cycle, and paleoclimate. Using daily data from six observation station across the IMC (Bukit tinggi, Jambi, Denpasar, Makasar, Manado, and Palau Island), the variability of δ18O was explored. Observation times for each station were different. Bukit Tinggi (GAW) was from Jan. 2001 - Mar. 2010, Jambi (JMB) was from Apr. 2001 - Dec. 2005, Denpasar (DPS), Makassar (MKS), Manado (MND) were from Nov. 2002 - Mar. 2010, and Palau Island (PLL) was from Dec. 2001 - May 2007. Daily average value of δ18O were -7.57‰, -5.41‰, -3.15‰, -6.12‰, -5.49‰ and -4.26‰ for GAW, JMB, DPS, MKS, MND and PLL respectively. Daily value of δ18O in GAW has the lowest value compare with the other station was because the location of GAW station located at high altitude. High correlation of variability of δ18O and Madden-Julian Oscillation (MJO) was observed at western part of the IMC (GAW and JMB), and northern part of the IMC (MKS, MND, and PLL), meanwhile δ18O variability at DPS was less correlated with MJO compare with other stations. Preliminary result from Color Moisture Analysis (CMA) model revealed that precipitable water at GAW and JMB stations was mostly occupied by water vapor evaporated from the Indian Ocean. However, precipitable water at other stations was mostly composed of water vapor evaporated from the Java Sea and the Pacific Ocean. These findings indicate

  12. Refining Upper Mantle Structure in the North American continent using Spectral Element method

    NASA Astrophysics Data System (ADS)

    Romanowicz, B. A.; Yuan, H.; Cupillard, P.

    2011-12-01

    Our recently published azimuthally anisotropic tomographic model of North America has revealed a rapid change of fast axis direction at mid-lithospheric depths in the North American craton (Yuan and Romanowicz, 2010). Shear wave receiver functions also report a sharp negative velocity gradient in this depth range at many of the cratonic stations (Abt et al., 2010; Fischer et al., 2010), marking a mid-lithospheric-discontinuity (MLD; Fischer et al., 2010). The MLD is also found in other continents (e.g., Ford et al., 2010) and may reflect a global feature associated with the shear wave velocity drop around 100 km found from long range profiles (Thybo, 2006; Romanowicz, 2009). Further exploring the nature of this mid-lithospheric boundary, and better constraining the absolute values of shear velocities of the lithospheric layers becomes a timely endeavor as the Transportable Array (TA) sweeps across the continental US. We conduct a refined 3D tomographic inversion of the cratonic North American upper mantle. The new inversion utilizes shorter period waveforms (down to 40 s) from over 100 local and regional events, and a regional Spectral Element code, RegSEM (Cupillard et al., 2011) to compute the forward synthetics. RegSEM includes ellipticity, attenuation, arbitrary anisotropy, non-conformal mapping of discontinuities, and can accurately represent scattering and focusing/defocusing effects caused by the 3D Earth structure. We apply a hybrid iterative inversion approach that uses accurate RegSEM synthetics and computationally efficient 2D finite frequency kernels based on NACT normal mode perturbation theory (Li and Romanowicz, 1995). We also test the use of much more time-consuming numerical Frechet kernels computed using RegSEM and the adjoint formalism. Our initial results confirm a lithospheric thickness in the craton of ~200-250 km. Along the eastern margin of the craton, a noticeable band of low velocity structure closely follows the Grenville

  13. Redox state and water content in the upper mantle: Linkages to the atmosphere, hydrosphere and continents

    NASA Astrophysics Data System (ADS)

    Li, Zhengxue

    Geochemical and petrologic tools were deployed to investigate the redox state and water content of the earth's upper mantle. Study results are discussed in the context of their linkages to the atmospheric oxygen level, hydrospheric water budget and lithospheric evolution of continents. Because the partitioning of V is redox-sensitive and otherwise similar to that of Sc which is not redox sensitive, the V/Sc ratios of basalts of different ages act as a natural recorder of the redox states of the upper mantle. Through a comparison between global mid-ocean ridge basalts and Archean basalts, the fO2 of the upper mantle was inferred to have changed by no more than 0.3 log units since Archean. Combined with results from a thermodynamic model simulating the redox reactions of volcanic gases, this observation argues against the idea that the increase in oxygen in the atmosphere ˜2.3 billion years ago was caused by redox transition in the upper mantle. Through a geochemical and petrologic study at the Feather River Ophiolite (in northern California), global water recycling rates at subduction zones were estimated based on reconstructed serpentinization depths for the oceanic lithospheric mantle. Within uncertainties, the estimated water recycling rates roughly match global volcanic dewatering rates, which suggest the hydrospheric water storage is current at steady-state. Based on water contents measured in mantle xenoliths from the Colorado Plateau and vicinity, the idea that the lithospheric mantle beneath the western North America was rehydrated by the dewatering of the flat-subducting Farallon slab is confirmed. As predicted by an updated flow law for olivine aggregates, hydration might have weakened the basal lithosphere beneath the Colorado Plateau and thus induced lithospheric thinning by ˜15 km as a result of basal erosion. Extrapolation of the flow law to thick, cratonic lithosphere further suggests lithospheric thinning of much larger extents can occur if enough

  14. Suicidal behaviour across the African continent: a review of the literature

    PubMed Central

    2014-01-01

    Background Suicide is a major cause of premature mortality worldwide, but data on its epidemiology in Africa, the world’s second most populous continent, are limited. Methods We systematically reviewed published literature on suicidal behaviour in African countries. We searched PubMed, Web of Knowledge, PsycINFO, African Index Medicus, Eastern Mediterranean Index Medicus and African Journals OnLine and carried out citation searches of key articles. We crudely estimated the incidence of suicide and suicide attempts in Africa based on country-specific data and compared these with published estimates. We also describe common features of suicide and suicide attempts across the studies, including information related to age, sex, methods used and risk factors. Results Regional or national suicide incidence data were available for less than one third (16/53) of African countries containing approximately 60% of Africa’s population; suicide attempt data were available for <20% of countries (7/53). Crude estimates suggest there are over 34,000 (inter-quartile range 13,141 to 63,757) suicides per year in Africa, with an overall incidence rate of 3.2 per 100,000 population. The recent Global Burden of Disease (GBD) estimate of 49,558 deaths is somewhat higher, but falls within the inter-quartile range of our estimate. Suicide rates in men are typically at least three times higher than in women. The most frequently used methods of suicide are hanging and pesticide poisoning. Reported risk factors are similar for suicide and suicide attempts and include interpersonal difficulties, mental and physical health problems, socioeconomic problems and drug and alcohol use/abuse. Qualitative studies are needed to identify additional culturally relevant risk factors and to understand how risk factors may be connected to suicidal behaviour in different socio-cultural contexts. Conclusions Our estimate is somewhat lower than GBD, but still clearly indicates suicidal behaviour is an

  15. Efficacy of Duloxetine in the Early Management of Urinary Continence after Radical Prostatectomy

    PubMed Central

    Alan, Cabir; Eren, Ali E.; Ersay, Ahmet R.; Kocoglu, Hasan; Basturk, Gokhan; Demirci, Emrah

    2015-01-01

    Aim To evaluate the efficacy of early duloxetine therapy in stress urinary incontinence occurring after radical prostatectomy (RP). Material and Method Patients that had RP were randomly divided into 2 groups following the removal of the urinary catheter. Group A patients (n = 28) had pelvic floor exercise and duloxetine therapy. Group B patients (n = 30) had only pelvic floor exercise. The incontinence status of the patients and number of pads were recorded and 1-hour pad test and Turkish validation of International Consultation on Incontinence Questionnaire-Short Form test were applied to the patients at the follow-up. Results When the dry state of the patients was evaluated, 5, 17, 3, and 2 of 28 Group A patients stated that they were completely dry in the 3rd, 6th, 9th and 12th month respectively and pad use was stopped. There was no continence in 30 Group B in the first 3 months. Twelve, 6, and 8 patients stated that they were completely dry in the 6th, 9th and 12th month, respectively. But 3 of 4 patients in whom dryness could not be provided were using a mean of 7.6 pads in the first day and a mean of 1.3 pads after 1 year. When pad use of the patients was evaluated, the mean monthly number of pad use was determined to be 6.2 (4-8) in the initial evaluation, 2.7 (0-5) in the in 3rd month, 2 (0-3) in the 6th month and 1.6 (0-2) pad/d in the 9th month in the group taking medicine. The mean monthly number of pads used was determined to be 5.8 (4-8) in the initial evaluation, 4.3 (3-8) in the 3rd month, 3 (0-6) in the 6th month and 1.6 (0-6) pad/d in the 9th month in the group not taking medicine. Conclusion According to the results, early duloxetine therapy in stress urinary incontinence that occurred after RP provided early continence. PMID:26195963

  16. Ecosystem modelling, scaling, benchmarking and data assimilation for the Australian continent

    NASA Astrophysics Data System (ADS)

    Evans, B. J.

    2013-12-01

    Modelling terrestrial biosphere processes in the world's driest inhabited continent presents some unique challenges, but also excellent opportunities to capitalize on major data infrastructure projects led by the Terrestrial Ecosystem Research Network (TERN). TERN, Australia's counterpart to NEON, has charged its ecosystem Modelling And Scaling InfrasTructure facility (e-MAST) with enhancing the national capacity for model benchmarking, data assimilation and data-model integration. e-MAST models the Australian terrestrial biosphere in space and time from various disciplinary perspectives. The foundation for all e-MAST modelling is ANUCLIMATE, a set of well-founded, high-resolution estimates of key climate variables (minimum and maximum temperature, precipitation, vapour pressure) from the 1970s up to near the present. Using all reliable meteorological measurements, we have enhanced the standard (ANUSPLIN) approach to allow interpolation of all variables at daily time resolution to a common 0.01 degree grid. Satellite data assimilation is used to provide continent-wide fields of derived variables including stomatal conductance, evapotranspiration and soil moisture. Plant productivity has been modelled by fusion of eddy-covariance CO2 flux measurements with satellite reflectance data, exploiting the well-tested light-use-efficiency modelling approach. Working towards the next generation of robust, process-based ecosystem models, we are synthesizing observations of plant biophysical and physiological traits; developing gridded surfaces of these traits; and working with TERN's MultiScale Plot Network to improve national coverage of trait measurements. Evaluation and benchmarking of models is based on the Protocol for the Analysis of Land Surface Models (PALS), which is being extended from its original core of flux data-model comparison ';experiments' to encompass more data types, including remote atmospheric CO2¬ concentrations and streamflow measurements, which (when

  17. Evaluation of the Interplate and Intraplate Deformations of the African Continent Using cGNSS Data

    NASA Astrophysics Data System (ADS)

    Apolinário, J. P.; Fernandes, R. M. S.; Bos, M. S.; Meghraoui, M.; Miranda, J. M. A.

    2014-12-01

    Two main plates, Nubia and Somalia, plus some few more tectonic blocks in the East African Rift System (EARS) delimit the African continent. The major part of the external plate boundaries of Africa is well defined by oceanic ridge systems with the exception of the Nubia-Eurasia complex convergence-collision tectonic zone. In addition, the number and distribution of the tectonic blocks along the EARS region is a major scientific issue that has not been completely answered so far. Nevertheless, the increased number of cGNSS (continuous Global Navigation Satellite Systems) stations in Africa with sufficient long data span is helping to better understand and constrain the complex sub-plate distribution in the EARS as well as in the other plate boundaries of Africa. This work is the geodetic contribution for the IGCP-Project 601 - "Seismotectonics and Seismic Hazards in Africa". It presents the current tectonic relative motions of the African continent based on the analysis of the estimated velocity field derived from the existing network of cGNSS stations in Africa and bordering plate tectonics. For the majority of the plate pairs, we present the most recent estimation of their relative velocity using a dedicated processing. The velocity solutions are computed using HECTOR, a software that takes into account the existing temporal correlations between the daily solutions of the stations. It allows to properly estimate the velocity uncertainties and to detect any artifacts in the time-series. For some of the plate pairs, we compare our solutions of the angular velocities with other geodetic and geophysical models. In addition, we also study the sensitivity of the derived angular velocity to changes in the data (longer data-span for some stations) for tectonic units with few stations, and in particular for the Victoria and Rovuma blocks of the EARS. Finally, we compute estimates of velocity fields for several sub-regions correlated with the seismotectonic provinces and

  18. An Analysis of Surface and Subsurface Lineaments and Fractures for Oil and Gas Exploration in the Mid-Continent Region

    SciTech Connect

    Guo, Genliang; and George, S.A.

    1999-04-08

    An extensive literature search was conducted and geological and mathematical analyses were performed to investigate the significance of using surface lineaments and fractures for delineating oil and gas reservoirs in the Mid-Continent region. Tremendous amount of data were acquired including surface lineaments, surface major fracture zones, surface fracture traces, gravity and magnetic lineaments, and Precambrian basement fault systems. An orientation analysis of these surface and subsurface linear features was performed to detect the basic structural grains of the region. The correlation between surface linear features and subsurface oil and gas traps was assessed, and the implication of using surface lineament and fracture analysis for delineating hydrocarbon reservoirs in the Mid-Continent region discussed. It was observed that the surface linear features were extremely consistent in orientation with the gravity and magnetic lineaments and the basement faults in the Mid-Continent region. They all consist of two major sets bending northeast and northwest, representing, therefore, the basic structural grains of the region. This consistency in orientation between the surface and subsurface linear features suggests that the systematic fault systems at the basement in the Mid-Continent region have probably been reactivated many times and have propagated upward all the way to the surface. They may have acted as the loci for the development of other geological structures, including oil and gas traps. Also observed was a strong association both in orientation and position between the surface linear features and the subsurface reservoirs in various parts of the region. As a result, surface lineament and fracture analysis can be used for delineating additional oil and gas reserves in the Mid-Continent region. The results presented in this paper prove the validity and indicate the significance of using surface linear features for inferring subsurface oil and gas reservoirs

  19. Maritime Continent rainfall variability during the TRMM era: The role of monsoon, topography and El Niño Modoki

    NASA Astrophysics Data System (ADS)

    As-syakur, Abd. Rahman; Osawa, Takahiro; Miura, Fusanori; Nuarsa, I. Wayan; Ekayanti, Ni Wayan; Dharma, I. Gusti Bagus Sila; Adnyana, I. Wayan Sandi; Arthana, I. Wayan; Tanaka, Tasuku

    2016-09-01

    Rainfall is among the most important climatic elements of the Maritime Continent. The Maritime Continent rainfall climate is uniquely located in the world's most active convective area. Satellite data measured by the Tropical Rainfall Measuring Mission (TRMM) 3B43 based high-resolution rainfall products represent monthly Maritime Continent rainfall characteristics over 16 years. Several statistical scores were employed to analyse annual means, linear trends, seasonal means, and anomalous Maritime Continent rainfall characteristic percentages. The effects of land and topography on rainfall quantities were also studied and compared with the Global Precipitation Climatology Project (GPCP) gridded precipitation estimates which has low-resolution. Comparison also applied on linear correlation and partial correlation techniques to determine the relationship between rainfall and the El Niño Modoki and El Niño-Southern Oscillation (ENSO; hereafter conventional El Niño). The results show that north-south Maritime Continent precipitation is associated with and generated by the northwest and southeast monsoon patterns. In addition, the large-scale circulations are linked with heavy rainfall over this land-ocean region due to large-scale island-topography-induced convective organization. The rainfall responses to El Niño Modoki and conventional El Niño clearly indicated the times at which the conventional El Niño had a higher impact than El Niño Modoki, especially during northern winter and spring, and vice versa during northern fall, and similarly affect during northern summer. Furthermore, the dynamic movements of rainfall anomaly that are caused by El Niño Modoki and the conventional El Niño events spanned from the southwest during June-July-August (JJA) to throughout the northeast ending in March-April-May (MAM).

  20. A Geophysical Overview of the Structure and Evolution of the Crust of the Mid-Continent Region of North America

    NASA Astrophysics Data System (ADS)

    Keller, G. R., Jr.

    2015-12-01

    A variety of geophysical data, including newly released 3-D seismic reflection data, show us that the crustal structure of the Mid-Continent region of North America is very complex. The dimensions of many of the crustal structures is very large by global standards, and thus, they are a tectonic puzzle because of their size, structural complexity, and distance from active plate margins that usually create the driving mechanisms for intraplate deformation evident. The crust of the Mid-Continent region formed during a period of continental growth that extended from about 1.8 to 0.9 Ga. The impressive Mid-Continent rift system (MCRS) tried to interrupt this period of continental growth at about 1.1 Ga but it its western arm failed even though it modified the crust massively. However, the supercontinent resulting from this growth did not survive long and began to break up by ~700 Ma. This period of rifting established the structural framework of the southern Mid-Continent region, subsequent Early Paleozoic basin development, and at least partly, the formation of the Ancestral Rocky Mountains in the late Paleozoic. The Southern Oklahoma aulacogen (SOA) is an impressive example of this rifting event. The deformation that formed the Ancestral Rocky Mountains resulted in massive inversion of SOA rift structures and is due to a plate collision in the late Paleozoic whose origin is under debate. There has been increased emphasis on the use of gravity, magnetic, seismic, drilling, and remote sensing data in studies of the Mid-Continent region. For example, the MCRS is traditionally viewed as ending in central Kansas and the SOA can be interpreted as ending in the Texas panhandle. However, we used enhancement of gravity and magnetic data, seismic data, geologic mapping, and deep-drilling data to study its southern extent, and it appears that the MCRS could extend further southward beneath the much younger Anadarko basin of Oklahoma to abut the SOA.

  1. The newfoundland basin - Ocean-continent boundary and Mesozoic seafloor spreading history

    NASA Technical Reports Server (NTRS)

    Sullivan, K. D.

    1983-01-01

    It is pointed out that over the past 15 years there has been considerable progress in the refinement of predrift fits and seafloor spreading models of the North Atlantic. With the widespread acceptance of these basic models has come increasing interest in resolution of specific paleogeographic and kinematic problems. Two such problems are the initial position of Iberia with respect to North America and the geometry and chronology of early (pre-80 m.y.) relative motions between these two plates. The present investigation is concerned with geophysical data from numerous Bedford Institute/Dalhousie University cruises to the Newfoundland Basin which were undrtaken to determine the location of the ocean-continent boundary (OCB) and the Mesozoic spreading history on the western side. From the examination of magnetic data in the Newfoundland Basin, the OCB east of the Grand Banks is defined as the seaward limit of the 'smooth' magnetic domain which characterizes the surrounding continental shelves. A substantial improvement in Iberia-North America paleographic reconstructions is achieved.

  2. Prevalence of abnormal urodynamic test results in continent women with severe genitourinary prolapse.

    PubMed

    Rosenzweig, B A; Pushkin, S; Blumenfeld, D; Bhatia, N N

    1992-04-01

    Twenty-two clinically continent women with severe genitourinary prolapse were evaluated urodynamically to determine the prevalence of urodynamic abnormalities that could lead to potential urinary incontinence. Urodynamic testing found an occult incontinence disorder in 13 women (59%), of whom four had urine loss during cough pressure profiles after pessary placement, four had uninhibited detrusor contractions during retrograde medium-fill water cystometry, and five had both stress urinary incontinence and an unstable bladder. Therefore, nine of the 22 patients (41%) had uninhibited detrusor contractions during urodynamic testing. However, uroflowmetry did not reveal voiding dysfunction in this group, although peak flow rates appeared to be lower in the subgroup of women manifesting uninhibited detrusor contractions. Associated symptoms of frequency, nocturia, and urgency occurred in 41% of the women in this study; four of nine (44%) who had normal urodynamic test results, five of 13 (38%) who had abnormal test results, and five of nine (56%) who had an unstable bladder. Therefore, associated symptoms could not be used to determine which women would have abnormal urodynamic test results. These preliminary results suggest that women with genitourinary prolapse may be at risk for an occult incontinence disorder that is masked by the prolapse and that could manifest after corrective surgery for prolapse. Urodynamic testing is suggested for women with genitourinary prolapse who present with or without symptoms of incontinence, so that more data can be obtained to determine the importance of abnormal test results. PMID:1553172

  3. Dynamic Earth Models: Sea Level and Vertical Motion of Continents since the Late Cretaceous

    NASA Astrophysics Data System (ADS)

    Spasojevic, S.; Gurnis, M.

    2010-12-01

    We show results from global dynamic earth models (DEMs) since the Late Cretaceous, which combine inverse and forward models of mantle convection, with viscosity that varies vertically and laterally. DEMs assimilate plate tectonic reconstructions, and account for the influence of the geoid and the evolving paleogeography of the sea floor self-consistently. Global DEMs are computed in the mantle frame, but we implement the integrated plate reconstruction-mantle convection system that enables linkage between geologic observations obtained in a plate frame of reference and dynamic topography, which is essential for sea-level studies. Since DEMs account for the most important factors controlling long-term sea-level change self-consistently, we present implications for the influence of the mantle on vertical motion of earth’s surface and regional and global sea-level change since Late Cretaceous. We find that neither dynamic topography nor eustasy dominant the global patterns of marine sedimentation on continents since the Late Cretaceous. Dynamic topography appears to be important in controlling the flooding patterns in North America, Australia and southern India since the Late Cretaceous, Sundaland since the Oligocene, and Arabia during Cenozoic. Eustasy has a larger role in controlling flooding in Eurasia and northern India. Mantle dynamics also seems to be an important factor contributing to Cenozoic long-wavelength tilting in Australia and Siberia. Interpretation of modeling results and the relative importance of eustatic versus dynamic factors is difficult in Africa and South America due to either unknown paleotopography or limited stratigraphic data.

  4. The origin and geologic evolution of the East Continent Rift Basin

    SciTech Connect

    Drahovzal, J.A. . Kentucky Geological Survey)

    1992-01-01

    The East Continent Rift Basin (ECRB) is a newly recognized, dominantly sedimentary-volcanic Proterozoic rift basin that apparently represents the southern extension of the Keweenawan Midcontinent Rift. The ECRB extends from central Michigan at least as far south as south-central Kentucky. The inferred age of the rift fill is approximately 1,000 Ma. Evidence supporting a rift origin for the ECRB includes: interbedding of continental flood basalts and felsic volcanics with siliciclastics; sedimentary fill consisting of distal, arid-climate alluvial fan sediments that lack metamorphic lithologies; close proximity and similar lithologic succession to the Keweenawan rift-fill rocks of the Michigan Basin; and inferred marginal block faulting of Granite-Rhyolite Province rocks near the western edge of the ECRB. ECRB evolution is interpreted as follows: (1) formation of Granite-Rhyolite Province rocks (1,500--1,340 Ma); (2) Keweenawan crustal extension and rifting with development of central mafic complexes, emplacement of volcanic rocks, and deposition of siliciclastic fill from eroded marginal Granite-Rhyolite Province tilted fault blocks (ca 1,000 Ma); (3) overthrusting of the Grenville allochthon and associated foreland thrusting and folding of the rift sequence rocks together with deposition of foreland basin sediments (975---890 Ma); (4) Late Proterozoic erosional removal of the foreland basin sediments and interpreted wrench faulting along the Grenville Front (post-975 to pre-570 Ma); and (5) tectonic inversion, with the ECRB area remaining relatively high during major cambrian subsidence in central Kentucky (590--510 Ma).

  5. Biogeochemistry of Hypersaline Springs Supporting a Mid-Continent Marine Ecosystem: An Analogue for Martian Springs?

    NASA Astrophysics Data System (ADS)

    Grasby, Stephen E.; Londry, Kathleen L.

    2007-08-01

    Hypersaline springs that host unique mid-continent marine ecosystems were examined in central Manitoba, Canada. The springs originate from a reflux of glacial meltwater that intrudes into underlying bedrock and dissolved buried salt beds. Two spring types were distinguished based both on flow rate and geochemistry. High flow springs (greater than 10 L/s) hosted extensive marine microbial mats, which were dominated by algae but also included diverse microbes. These varied somewhat between springs as indicated by changes in profiles of fatty acid methyl esters. Culture studies confirmed the presence of sulfate-reducing bacteria in sediments at the high flow sites. In contrast, low flow springs were affected by solar evaporation, increasing salinity, and temperature. These low flow springs behaved more like closed nutrient-limited systems and did not support microbial mats. Direct comparison of the high and low flow springs revealed interesting implications for the potential to record biosignatures in the rock record. High flow springs have abundant, well-developed microbial mats, which desiccate and are cemented along the edges of the spring pools; however, the high mass flux overwhelms any geochemical signature of microbial activity. In contrast, the nutrient-limited low flow sites develop strong geochemical signatures of sulfate reduction, even in the absence of microbial mats, due to less dilution with the lower flows. Geochemical and physical evidence for life did not correlate with the abundance of microbial life but, rather, with the extent to which the biological system formed a closed ecosystem.

  6. Propagating convective system as a rainfall connection between southwestern Tibetan Plateau and Indian continent

    NASA Astrophysics Data System (ADS)

    Dong, W.; Lin, Y.; Xie, Y.

    2014-12-01

    The Tibetan Plateau (TP) is called "Asia's Water Tower" because it is the headwaters of many major rivers in Asia, upon which the production and living of nearly 1/6 world population strongly depends. Precipitation and its future change over the TP pose a large socio-economic impact on the surrounding nations. Using multiple precipitation datasets and CMIP5 model simulations, summer (June to September) precipitation over the TP and Indian continent is investigated. We note a close linkage of rainfall over the southwestern Tibetan Plateau (SWTP) and central-eastern India. Such a linkage is maintained by frequent propagation of convective systems from northern Indian lower lands over the high mountain range into SWTP. An objective propagation identification method suggests such propagation contributes nearly half of the total summer rainfall in SWTP. The propagation is prominent from late June to mid-September. Its occurrence is rather stable and appears not to be strongly modulated by Indian monsoon strength. The propagation also modifies the rainfall diurnal cycle with a second peak near midnight in addition to the late afternoon peak induced by localized convective systems. Favorable environmental conditions for propagations are also explored.

  7. Long aftershock sequences within continents and implications for earthquake hazard assessment.

    PubMed

    Stein, Seth; Liu, Mian

    2009-11-01

    One of the most powerful features of plate tectonics is that the known plate motions give insight into both the locations and average recurrence interval of future large earthquakes on plate boundaries. Plate tectonics gives no insight, however, into where and when earthquakes will occur within plates, because the interiors of ideal plates should not deform. As a result, within plate interiors, assessments of earthquake hazards rely heavily on the assumption that the locations of small earthquakes shown by the short historical record reflect continuing deformation that will cause future large earthquakes. Here, however, we show that many of these recent earthquakes are probably aftershocks of large earthquakes that occurred hundreds of years ago. We present a simple model predicting that the length of aftershock sequences varies inversely with the rate at which faults are loaded. Aftershock sequences within the slowly deforming continents are predicted to be significantly longer than the decade typically observed at rapidly loaded plate boundaries. These predictions are in accord with observations. So the common practice of treating continental earthquakes as steady-state seismicity overestimates the hazard in presently active areas and underestimates it elsewhere. PMID:19890328

  8. Continent catheterizable conduit for urinary diversion in children: Applicability and acceptability

    PubMed Central

    Solanki, Shailesh; Babu, Muniamjanappa Narendra; Jadhav, Vinay; Shankar, Gowri; Ramesh, Santhanakrishnan

    2015-01-01

    Background: Continent catheterizable conduit (CCC) has made clean intermittent catheterization (CIC) painless and easy. It is applicable in diverse clinical conditions. Nonetheless, convincing the parents for the need of conduit procedure is still difficult. Materials and Methods: A prospective study, included children who underwent CCC procedure from March 2008 to February 2013. The data were assessed for; diagnosis, type of conduit, number of preoperative counselling sessions before acceptance, role of “self-help group” in decision making, parental concern and satisfaction for the procedure. Results: Twenty-nine patients (males; 24, females; 5) underwent CCC procedure for various clinical conditions. The multiple preoperative counselling sessions and creation of “self-help groups” were helped them for decision making. The main concerns among parents were: (1) Impact of procedure on future fertility and sexual life. (2) Patency of native urethral channel. (3) Permanent urinary stoma over the abdomen. Conclusion: CCC procedures are applicable to a wide array of clinical situations with a good outcome. The acceptability of the CCC procedure improves with preoperative counselling of parent/child, initiation of preoperative per urethral CIC and creation of self-help groups. PMID:25659547

  9. A VLBI baseline post-adjustment approach for station velocity estimation in Eurasian continent

    NASA Astrophysics Data System (ADS)

    Zhang, Zhibin; Liu, Xiang

    2014-10-01

    Baseline lengths and their time-derivatives among 58 geodetic VLBI stations were fitted by using 4439 observing sessions from the International VLBI Service for Geodesy and Astrometry (IVS). First, the velocities of eight stations in Eurasian continent were set as unknown quantities. Then, two standard global solutions from 3523 IVS sessions and 1110 sessions from database code XA, respectively, were applied prior to all-station coordinates and the non-estimated station velocities. Finally, from the relations among the coordinates, velocities, baseline length and its time-derivative, two types of baseline post-adjustment (BPA) were used to estimate the velocities of the eight stations. We discuss the data processing details, including the effect of different prior values for the stations and the optimal solution. The results suggest that the precision of the station velocities based on the proposed approach is comparable to that of the global solution of the XA sessions. The baseline structure and the prior values of the stations affect the velocity estimates. Compared to the standard method of velocity estimation, there are no external constrains and conditions used in the proposed method.

  10. Early onset of industrial-era warming across the oceans and continents.

    PubMed

    Abram, Nerilie J; McGregor, Helen V; Tierney, Jessica E; Evans, Michael N; McKay, Nicholas P; Kaufman, Darrell S

    2016-08-25

    The evolution of industrial-era warming across the continents and oceans provides a context for future climate change and is important for determining climate sensitivity and the processes that control regional warming. Here we use post-ad 1500 palaeoclimate records to show that sustained industrial-era warming of the tropical oceans first developed during the mid-nineteenth century and was nearly synchronous with Northern Hemisphere continental warming. The early onset of sustained, significant warming in palaeoclimate records and model simulations suggests that greenhouse forcing of industrial-era warming commenced as early as the mid-nineteenth century and included an enhanced equatorial ocean response mechanism. The development of Southern Hemisphere warming is delayed in reconstructions, but this apparent delay is not reproduced in climate simulations. Our findings imply that instrumental records are too short to comprehensively assess anthropogenic climate change and that, in some regions, about 180 years of industrial-era warming has already caused surface temperatures to emerge above pre-industrial values, even when taking natural variability into account. PMID:27558063

  11. SELECTION AND TREATMENT OF STRIPPER GAS WELLS FOR PRODUCTION ENHANCEMENT IN THE MID-CONTINENT

    SciTech Connect

    Scott Reeves

    2003-03-01

    Stripper gas wells are an important source of domestic energy supply and under constant threat of permanent loss (shut-in) due to marginal economics. In 1998, 192 thousand stripper gas wells produced over a Tcf of gas, at an average rate of less than 16 Mcfd. This represents about 57% of all producing gas wells in the onshore lower-48 states, yet only 8% of production. Reserves of stripper gas wells are estimated to be only 1.6 Tcf, or slightly over 1% of the onshore lower-48 total (end of year 1996 data). Obviously, stripper gas wells are at the very margin of economic sustenance. As the demand for natural gas in the U.S. grows to the forecasted estimate of over 30 Tcf annually by the year 2010, supply from current conventional sources is expected to decline. Therefore, an important need exists to fully exploit known domestic resources of natural gas, including those represented by stripper gas wells. The overall objectives of this project are to develop an efficient and low-cost methodology to broadly categorize the well performance characteristics for a stripper gas field, identify the high-potential candidate wells for remediation, and diagnose the specific causes for well underperformance. With this capability, stripper gas well operators can more efficiently and economically produce these resources and maximize these gas reserves. A further objective is to identify/develop, evaluate and test ''new and novel,'' economically viable remediation options. Finally, it is the objective of this project that all the methods and technologies developed in this project, while being tested in the Mid-Continent, be widely applicable to stripper gas wells of all types across the country. The project activities during the reporting period were: (1) Prepared various materials to describe the project for promotional purposes and to attract potential industry partners. Materials included slides for DOE's displays at the SPE Eastern Regional and Annual Technical Conference, and

  12. Climate deterioration on the Asian continent after the Middle Eocene Climatic Optimum (MECO)

    NASA Astrophysics Data System (ADS)

    Dupont-Nivet, G.; Bosboom, R. E.; Hemmo, A.; Hoorn, C.; van den Berg, B.; Guo, Z.

    2012-12-01

    Cenozoic global climate cooling leading from greenhouse to icehouse conditions, occurred mainly during a peculiar interval referred to as the 'doubthouse' from the early Eocene (~50 Ma) until permanent Antarctic ice-sheet formation at the ~34 Ma Eocene-Oligocene transitions (EOT). Understanding this critical interval characterized by periodic polar ice-sheet formations as well as short-lived warming events (hyperthermals), of which the Middle Eocene Climatic Optimum (MECO) is most noticeable, requires high resolution records that are being gathered in marine basins but are still lacking in the terrestrial realm. Here, we analyze the lithofacies and palynological changes within four lacustrine sedimentary sections from the central Asian continent (Xining Basin, NW China), precisely dated with magnetostratigraphy between ~43 and ~36 Ma. We show that a permanent regional aridification and a shift to obliquity-dominated cyclicity is, within uncertainty, concomitant with peak warming of the MECO records in the marine realm at ~39.3 Ma (basal part of chron C18n.2n). We interpret our results to indicate that incipient polar ice sheet formation in association with higher climate variability started directly following the MECO, marking the onset of a major cooling step leading to the EOT. The permanent - rather than transient - expression of the MECO in Asian terrestrial paleoenvironments suggests this warming event marks the crossing of a critical threshold for atmospheric conditions in their course from greenhouse to icehouse conditions.

  13. Wet Deposition Measurements across the Continent: Observations from The National Ecological Observatory Network

    NASA Astrophysics Data System (ADS)

    Taylor, J. R.; Goodman, K. J.; Luo, H.; Roehm, C. L.

    2013-12-01

    The National Ecological Observatory Network (NEON) is responsible for making observations of terrestrial, aquatic, and organismal ecology at 106 sites in 20 different eco-climatic domains across the North American continent. NEON will provide data on key local, meteorological, climate, and chemical variables, as well as their associated biogeochemical and biotic responses, in an effort to better understand and predict the effects of climate change, land-use change, and invasive species. The volume of data collected is expected to exceed hundreds of Terabytes per year and will be freely available via a web portal for use by researchers, educators, and policy makers. Chemical scavenging by wet deposition is a principle means of chemical inputs into an ecosystem. By the time NEON becomes fully operational in 2017; wet deposition will be collected and measured at 55 sites across the US. It is expected that these measurements will capture, among other compounds, the deposition of sulfate, ammonium, and nitrate spanning gradients and 'hot spots' across terrestrial and aquatic ecosystems. This poster will highlight the network planning for these measurements, the instrumentation and observational details, as well as opportunities to link these data products with external networks. Particular emphasis will be placed on how these measurements complement and link with other biogeochemical and climatological data products at NEON.

  14. The likelihood of observing dust-stimulated phytoplankton growth in waters proximal to the Australian continent

    NASA Astrophysics Data System (ADS)

    Cropp, R. A.; Gabric, A. J.; Levasseur, M.; McTainsh, G. H.; Bowie, A.; Hassler, C. S.; Law, C. S.; McGowan, H.; Tindale, N.; Viscarra Rossel, R.

    2013-05-01

    We develop a tool to assist in identifying a link between naturally occurring aeolian dust deposition and phytoplankton response in the ocean. Rather than examining a single, or small number of dust deposition events, we take a climatological approach to estimate the likelihood of observing a definitive link between dust deposition and a phytoplankton bloom for the oceans proximal to the Australian continent. We use a dust storm index (DSI) to determine dust entrainment in the Lake Eyre Basin (LEB) and an ensemble of modelled atmospheric trajectories of dust transport from the basin, the major dust source in Australia. Deposition into the ocean is computed as a function of distance from the LEB source and the local over-ocean precipitation. The upper ocean's receptivity to nutrients, including dust-borne iron, is defined in terms of time-dependent, monthly climatological fields for light, mixed layer depth and chlorophyll concentration relative to the climatological monthly maximum. The resultant likelihood of a dust-phytoplankton link being observed is then mapped as a function of space and time. Our results suggest that the Southern Ocean (north of 45°S), the North West Shelf, and Great Barrier Reef are ocean regions where a rapid biological response to dust inputs is most likely to be observed. Conversely, due to asynchrony between deposition and ocean receptivity, direct causal links appear unlikely to be observed in the Tasman Sea and Southern Ocean south of 45°S.

  15. Land-Use Change and Emerging Infectious Disease on an Island Continent

    PubMed Central

    McFarlane, Rosemary A.; Sleigh, Adrian C.; McMichael, Anthony J.

    2013-01-01

    A more rigorous and nuanced understanding of land-use change (LUC) as a driver of emerging infectious disease (EID) is required. Here we examine post hunter-gatherer LUC as a driver of infectious disease in one biogeographical region with a compressed and documented history—continental Australia. We do this by examining land-use and native vegetation change (LUCC) associations with infectious disease emergence identified through a systematic (1973–2010) and historical (1788–1973) review of infectious disease literature of humans and animals. We find that 22% (20) of the systematically reviewed EIDs are associated with LUCC, most frequently where natural landscapes have been removed or replaced with agriculture, plantations, livestock or urban development. Historical clustering of vector-borne, zoonotic and environmental disease emergence also follows major periods of extensive land clearing. These advanced stages of LUCC are accompanied by changes in the distribution and density of hosts and vectors, at varying scales and chronology. This review of infectious disease emergence in one continent provides valuable insight into the association between accelerated global LUC and concurrent accelerated infectious disease emergence. PMID:23812027

  16. High diversity of picornaviruses in rats from different continents revealed by deep sequencing.

    PubMed

    Hansen, Thomas Arn; Mollerup, Sarah; Nguyen, Nam-Phuong; White, Nicole E; Coghlan, Megan; Alquezar-Planas, David E; Joshi, Tejal; Jensen, Randi Holm; Fridholm, Helena; Kjartansdóttir, Kristín Rós; Mourier, Tobias; Warnow, Tandy; Belsham, Graham J; Bunce, Michael; Willerslev, Eske; Nielsen, Lars Peter; Vinner, Lasse; Hansen, Anders Johannes

    2016-01-01

    Outbreaks of zoonotic diseases in humans and livestock are not uncommon, and an important component in containment of such emerging viral diseases is rapid and reliable diagnostics. Such methods are often PCR-based and hence require the availability of sequence data from the pathogen. Rattus norvegicus (R. norvegicus) is a known reservoir for important zoonotic pathogens. Transmission may be direct via contact with the animal, for example, through exposure to its faecal matter, or indirectly mediated by arthropod vectors. Here we investigated the viral content in rat faecal matter (n=29) collected from two continents by analyzing 2.2 billion next-generation sequencing reads derived from both DNA and RNA. Among other virus families, we found sequences from members of the Picornaviridae to be abundant in the microbiome of all the samples. Here we describe the diversity of the picornavirus-like contigs including near-full-length genomes closely related to the Boone cardiovirus and Theiler's encephalomyelitis virus. From this study, we conclude that picornaviruses within R. norvegicus are more diverse than previously recognized. The virome of R. norvegicus should be investigated further to assess the full potential for zoonotic virus transmission. PMID:27530749

  17. Climate as a driver of continent-wide irruptions in boreal seed-eating birds (Invited)

    NASA Astrophysics Data System (ADS)

    Strong, C.; Zuckerberg, B.; Betancourt, J. L.

    2013-12-01

    Boreal seed-eating birds regularly breed and overwinter throughout Canada and Alaska, but every few years these species demonstrate impressive irruptive migrations out of the boreal forest and into more southerly regions. It is thought that irruptive migrations are inversely dependent on a circumboreally synchronized pattern of seed crop fluctuations in boreal trees; seed-eating boreal birds stay in the north when food is plentiful, but sojourn south when food is scarce. Because both seed production and bird irruptions are characterized by periodicity ranging from biennial to decadal cycles, there is a strong possibility that these ecological phenomena are driven by climate variability. Using over twenty years of data from Project FeederWatch (a national citizen science project), we found that 'super irruptions' are correlated with continent-wide irruptive events in pine siskin population, and that these irruptions are associated with multi-decadal climate variability of Pacific origin. We also investigate how climate variability may influence the distribution of boreal bird species across different regions of North America during winter, and evaluate results in the context of limited banding data to assess possible geographic pathways of irruptions.

  18. Conservation education in Madagascar: three case studies in the biologically diverse island-continent.

    PubMed

    Dolins, Francine L; Jolly, Alison; Rasamimanana, Hantanirina; Ratsimbazafy, Jonah; Feistner, Anna T C; Ravoavy, Florent

    2010-05-01

    Few Malagasy children and adults are aware of the rare and unique fauna and flora indigenous to their island-continent, including flagship lemur species. Even the Malagasy ancestral proverbs never mentioned lemurs, but these same proverbs talked about the now extinct hippopotamus. Madagascar's geography, history, and economic constraints contribute to severe biodiversity loss. Deforestation on Madagascar is reported to be over 100,000 ha/year, with only 10-15% of the island retaining natural forest [Green & Sussman, 1990]. Educating children, teacher-training, and community projects about environmental and conservation efforts to protect the remaining natural habitats of endangered lemur species provide a basis for long-term changes in attitudes and practices. Case studies of three conservation education projects located in different geographical regions of Madagascar, Centre ValBio, Madagacar Wildlife Conservation Alaotra Comic Book Project, and The Ako Book Project, are presented together with their ongoing stages of development, assessment, and outcomes. We argue that while nongovernmental organizational efforts are and will be very important, the Ministry of Education urgently needs to incorporate biodiversity education in the curriculum at all levels, from primary school to university. PMID:20039330

  19. Analysis of metagenomic data reveals common features of halophilic viral communities across continents.

    PubMed

    Roux, Simon; Enault, Francois; Ravet, Viviane; Colombet, Jonathan; Bettarel, Yvan; Auguet, Jean-Christophe; Bouvier, Thierry; Lucas-Staat, Soizick; Vellet, Agnès; Prangishvili, David; Forterre, Patrick; Debroas, Didier; Sime-Ngando, Telesphore

    2016-03-01

    Microbial communities from hypersaline ponds, dominated by halophilic archaea, are considered specific of such extreme conditions. The associated viral communities have accordingly been shown to display specific features, such as similar morphologies among different sites. However, little is known about the genetic diversity of these halophilic viral communities across the Earth. Here, we studied viral communities in hypersaline ponds sampled on the coast of Senegal (8-36% of salinity) using metagenomics approach, and compared them with hypersaline viromes from Australia and Spain. The specificity of hyperhalophilic viruses could first be demonstrated at a community scale, salinity being a strong discriminating factor between communities. For the major viral group detected in all samples (Caudovirales), only a limited number of halophilic Caudovirales clades were highlighted. These clades gather viruses from different continents and display consistent genetic composition, indicating that they represent related lineages with a worldwide distribution. Non-tailed hyperhalophilic viruses display a greater rate of gene transfer and recombination, with uncharacterized genes conserved across different kind of viruses and plasmids. Thus, hypersaline viral communities around the world appear to form a genetically consistent community that are likely to harbour new genes coding for enzymes specifically adapted to these environments. PMID:26472517

  20. FROM MICROCONTINENTS TO EXTENSIONAL ALLOCHTHONS: WITNESSES OF HOW CONTINENTS BREAK APART? (Invited)

    NASA Astrophysics Data System (ADS)

    Peron-Pinvidic, G.; Manatschal, G.

    2009-12-01

    It is well known that extensional processes can lead to different crustal configurations, depending notably on lithospheric composition, thermal structure and extension rate. Thereby, rifted margins are characterized, worldwide, by distinct tectonic, geological and magmatic contexts. Direct comparisons are not straightforward. However, even if different, these margins also present a limited number of crustal features that are regularly observed and described such as micro-continents, continental ribbons, H blocks, extensional allochthons and outer highs. If some of these structures have been proposed to be issued from plume-related events and strength differences between oceanic and continental lithosphere, it is still unclear how these different types of crustal bodies are generated and consequently what they may tell us about the underlying processes and associated tectonic evolution. However, we believe each of these features, by their similarities and differences, point to distinct processes (stretching, thinning, exhumation, magmatism, spreading). The aim of this contribution is to present these different "building stones", describe their characteristics and positions within the margins, and discuss the underlying tectonic processes and stratigraphic relationships related to their formation. We propose, using the example of the North Atlantic, that the superposition of specific deformation modes may explain the various types of crustal blocks and, as a consequence, that the occurrence of these various blocks are the witnesses of particular rifting processes.

  1. Depressive symptoms and psychosocial stress at work among older employees in three continents

    PubMed Central

    2012-01-01

    Background To assess whether an association of psychosocial stress at work with depressive symptoms among older employees is evident in a set of comparable empirical studies from Europe, North America and Asia. Methods Cross-sectional and longitudinal multivariate regression analyses of data from 4 cohort studies with elder workers (2004 and 2006) testing associations of psychosocial stress at work (‘effort-reward imbalance’; ‘low control’) with depressive symptoms. Results Cross-sectional analyses from 17 countries with 14.236 participants reveal elevated odds ratios of depressive symptoms among people experiencing high work stress compared to those with low or no work stress. Adjusted odds ratios vary from 1.64 (95% CI 1.02-2.63) in Japan to 1.97 (95% CI 1.75-2.23) in Europe and 2.28 (95% CI 1.59-3.28) in the USA. Odds ratios from additional longitudinal analyses (in 13 countries) controlling for baseline depression are smaller, but remain in part significant. Conclusion Findings indicate that psychosocial stress at work might be a relevant risk factor for depressive symptoms among older employees across countries and continents. This observation may call for global policy efforts to improve quality of work in view of a rapidly aging workforce, in particular in times of economic globalization. PMID:22818354

  2. Stratigraphy of Mid-Continent rift system in Kansas as revealed by recent exploration wells

    SciTech Connect

    Newell, K.D.; Berendsen, P.; Watney, W.L.; Doveton, J.H.; Steeples, D.

    1989-03-01

    The Texaco 1 Poersch well in Kansas (11,300 ft TD) was the first significant exploration test of the Mid-Continent Rift System (MRS). An upper succession of rift-related rocks (2846-7429 ft) contains approximately 90% mafic igneous rocks with minor pegmatites and 10% oxidized siltstone and arkose. Arkose and subarkose with minor siltstone and shale make up 90% of a lower succession (7429 ft to TD). The remaining lower succession is composed of mafic igneous rocks. Mafic rocks are typically alkali basalts. Individual flows (detected by presence of amygdules, interflow sediments, compositional differences, and oxidized zones) range in thickness from 20 to 250 ft. Sedimentary rocks in the lower succession are divided into three sequences, each 1000-2000 ft thick. The sequences overlie relatively thin mafic flows or intrusives. Each sequence is generally composed of fining-upward units (50-150 ft thick) attributed to episodic movement and erosion of fault blocks in alluvial fan-dominated sedimentary environments. Shales and siltstones are too oxidized to be viable petroleum source rocks, but gray shale with approximately 0.5% total organic carbon was found in the MRS by the 1-4 Finn well, 21 mi to the northeast. Geologic examination of several shallower Precambrian tests holes near 1 Poersch shows considerable variability in sedimentary and tectonic settings along the MRS. Correlation between wells in Kansas and exposed areas of the MRS is still problematic. Additional wells will be necessary to better understand its hydrocarbon potential.

  3. Sensitivity of the Maritime Continent precipitation to horizontal resolution in a coupled regional model

    NASA Astrophysics Data System (ADS)

    Li, Yue; Jourdain, Nicolas; Taschetto, Andréa; Gupta, Alex Sen; Masson, Sébastien; Cai, Wenju

    2015-04-01

    The Maritime Continent (MC) is centred at one of the major monsoon systems in the world. Characterized by massive tropical heating and precipitation, it is strongly influencing both the Hadley and Walker circulations. However, there are significant challenges in correctly represent climate of this region because of the complex topography and the arrangement of lands and seas. It is often argued that improved representation of the diurnal cycle over islands and the complex mesoscale circulation associated with land-sea contrast is important to energy and hydrological cycles of this region. To investigate the sensitivity of precipitation over the MC to model horizontal resolution, we perform three regional numerical experiments using the coupled NEMO-OASIS-WRF model at different horizontal resolutions of 3/4°, 1/4° and 1/12° in both atmosphere and ocean components. The 3/4° and 1/4° experiments are run on a large MC domain for 21 years (1989 to 2009), and the 1/12° experiment is nested within the 1/4° domain using two-way interactive nesting over 5 years. Increasing the resolution reduces biases in mean SST and mean precipitation. The precipitation distribution is also improved at higher resolution, particularly in coastal areas. A part of these improvements are related to different behaviours of the model physical schemes across the three resolutions. Other changes are interpreted in terms of land-sea breeze, that we describe through a new comprehensive method.

  4. Relationships between the Maritime Continent Heat Source and the El Niño-Southern Oscillation Phenomenon.

    NASA Astrophysics Data System (ADS)

    McBride, John L.; Haylock, Malcolm R.; Nicholls, Neville

    2003-09-01

    Various earlier studies have demonstrated that rainfall in the Maritime Continent-Indonesia region is strongly related to the El Niño-Southern Oscillation (ENSO) during the dry half of the year but has a very weak association with ENSO during the summer-wet season months. This relationship is investigated over a wider domain through the use of outgoing longwave radiation (OLR) data as a proxy for rainfall.Consistent with the hypothesis of Haylock and McBride, it is found that the large-scale structure of the low-order empirical orthogonal functions (EOFs) of OLR have a strong resemblance to the patterns of correlation between OLR and the Southern Oscillation index (SOI). This supports the hypothesis that the predictable component of rainfall is determined by the component that is spatially coherent, as quantified through EOF analysis.As was found earlier with rainfall, the region of largest correlation between interannual OLR anomalies and the SOI lies in the winter hemisphere. The predictable component of OLR (or rainfall) remains in the region of the Maritime Continent throughout the year and thus does not accompany the minimum OLR (maximum rainfall) during its annual interhemispheric progression as the major monsoon heat source.The sign of the OLR-SOI relationship is such that the Maritime Continent has increased rainfall during a La Niña or cold event. Patterns of correlation between sea surface temperature and the SOI show the existence of a region to the east of the Maritime Continent whereby sea surface temperature anomalies are positive during these (La Niña) conditions. This is in the sense of a direct relationship, that is, positive sea surface temperature anomalies corresponding to increased rainfall.The annual cycle of the sea surface temperature structure of ENSO is represented by the first EOF of the interannual sea surface temperature series for each separate calendar month. The region of the sea surface temperature anomaly giving the direct

  5. Cooling and exhumation of continents at billion-year time scales

    NASA Astrophysics Data System (ADS)

    Blackburn, T.; Bowring, S. A.; Perron, T.; Mahan, K. H.; Dudas, F. O.

    2011-12-01

    The oldest rocks on Earth are preserved within the continental lithosphere, where assembled fragments of ancient orogenic belts have survived erosion and destruction by plate tectonic and surface processes for billions of years. Though the rate of orogenic exhumation and erosion has been measured for segments of an orogenic history, it remains unclear how these exhumation rates have changed over the lifetime of any terrane. Because the exhumation of the lithospheric surface has a direct effect on the rate of heat loss within the lithosphere, a continuous record of lithosphere exhumation can be reconstructed through the use of thermochronology. Thermochronologic studies have typically employed systems sensitive to cooling at temperatures <300 °C, such as the (U-Th)/He and 40Ar/39Ar systems. This largely restricts their application to measuring cooling in rocks from the outer 10 km of the Earth's crust, resulting in a thermal history that is controlled by either upper crustal flexure and faulting and/or isotherm inflections related to surface topography. Combining these biases with the uplift, erosion and recycling of these shallow rocks results in a poor preservation potential of any long-term record. Here, an ancient and long-term record of lithosphere exhumation is constructed using U-Pb thermochronology, a geochronologic system sensitive to cooling at temperatures found at 20-50 km depth (400-650 °C). Lower crustal xenoliths provide material that resided at these depths for billions of years or more, recording a thermal history that is buried deep enough to remain insensitive to upper crustal deformation and instead is dominated by the vertical motions of the continents. We show how this temperature-sensitive system can produce a long-term integrated measure of continental exhumation and erosion. Preserved beneath Phanerozoic sedimentary rocks within Montana, USA, the Great Falls Tectonic Zone formed when two Archean cratons, the Wyoming Province and Medicine

  6. Petrology and tectonics of Phanerozoic continent formation: From island arcs to accretion and continental arc magmatism

    USGS Publications Warehouse

    Lee, C.-T.A.; Morton, D.M.; Kistler, R.W.; Baird, A.K.

    2007-01-01

    Mesozoic continental arcs in the North American Cordillera were examined here to establish a baseline model for Phanerozoic continent formation. We combine new trace-element data on lower crustal xenoliths from the Mesozoic Sierra Nevada Batholith with an extensive grid-based geochemical map of the Peninsular Ranges Batholith, the southern equivalent of the Sierras. Collectively, these observations give a three-dimensional view of the crust, which permits the petrogenesis and tectonics of Phanerozoic crust formation to be linked in space and time. Subduction of the Farallon plate beneath North America during the Triassic to early Cretaceous was characterized by trench retreat and slab rollback because old and cold oceanic lithosphere was being subducted. This generated an extensional subduction zone, which created fringing island arcs just off the Paleozoic continental margin. However, as the age of the Farallon plate at the time of subduction decreased, the extensional environment waned, allowing the fringing island arc to accrete onto the continental margin. With continued subduction, a continental arc was born and a progressively more compressional environment developed as the age of subducting slab continued to young. Refinement into a felsic crust occurred after accretion, that is, during the continental arc stage, wherein a thickened crustal and lithospheric column permitted a longer differentiation column. New basaltic arc magmas underplate and intrude the accreted terrane, suture, and former continental margin. Interaction of these basaltic magmas with pre-existing crust and lithospheric mantle created garnet pyroxenitic mafic cumulates by fractional crystallization at depth as well as gabbroic and garnet pyroxenitic restites at shallower levels by melting of pre-existing lower crust. The complementary felsic plutons formed by these deep-seated differentiation processes rose into the upper crust, stitching together the accreted terrane, suture and former

  7. Collaborative Taiwan-USA Seismic Onshore-Offshore Imaging of Arc-Continent Collision under Taiwan

    NASA Astrophysics Data System (ADS)

    Okaya, D. A.; Wang, C.; Kuo, Y. N.; Yen, H.; Huang, B.; Liang, W.; Shih, M.; Wen, S.; Wu, F. T.

    2009-12-01

    The Philippine Sea and Eurasian plates converge for over 2500 km along the east Asian continental margin. For nearly four-fifths of its northwestern boundary, the young Philippine Sea plate routinely subducts to the west under continental Eurasia as is marked by the Ryukyu island arc. However, the western Philippine Sea plate contains the Luzon island arc that is formed by eastward subduction of the South China Sea portion of the Eurasian plate. The island of Taiwan marks the location where (1) subduction reversal takes place and (2) impingement of the island arc with the continental Eurasian plate. The ongoing orogeny of Taiwan involves a complex interaction often considered the type example of arc-continent collision. Tectonic models to explain how this collision occurs and produces associated mountain building, of which Taiwan's is one of the fastest rising in the world, range from thin-skinned to lithospheric-scale end-members. In the thin skinned model, subduction of continental Eurasian mantle and lower crust is separated from a deforming crustal wedge by a plate boundary decollement. In the latter, deformation of crust and mantle occurs within a vertically contiguous system, with progressive thickening of continental mantle beneath the core of the mountain belt. The 3D geophysical signatures are fundamentally different between these models. The Taiwan Integrated Geodynamics Research (TAIGER) project is a joint USA-Taiwan program that has carried out several types of seismological studies in Taiwan. TAIGER carried out an onshore-offshore seismic experiment across and around Taiwan during March-June 2009. A 2D portable land array was deployed for 2+ months across Taiwan and contained 280 Taiwan and PASSCAL three-component recorders. Airgun sources were provided by the USA R/V Langseth which carried out 7000+ km MCS profiles (see McIntosh et al., this session). In addition, 3200 regional and local earthquakes occurred and were recorded during the land

  8. A link between reduced Barents-Kara sea ice and cold winter extremes over northern continents

    NASA Astrophysics Data System (ADS)

    Petoukhov, Vladimir; Semenov, Vladimir A.

    2010-11-01

    The recent overall Northern Hemisphere warming was accompanied by several severe northern continental winters, as for example, extremely cold winter 2005-2006 in Europe and northern Asia. Here we show that anomalous decrease of wintertime sea ice concentration in the Barents-Kara (B-K) seas could bring about extreme cold events like winter 2005-2006. Our simulations with the ECHAM5 general circulation model demonstrate that lower-troposphere heating over the B-K seas in the Eastern Arctic caused by the sea ice reduction may result in strong anticyclonic anomaly over the Polar Ocean and anomalous easterly advection over northern continents. This causes a continental-scale winter cooling reaching -1.5°C, with more than 3 times increased probability of cold winter extremes over large areas including Europe. Our results imply that several recent severe winters do not conflict the global warming picture but rather supplement it, being in qualitative agreement with the simulated large-scale atmospheric circulation realignment. Furthermore, our results suggest that high-latitude atmospheric circulation response to the B-K sea ice decrease is highly nonlinear and characterized by transition from anomalous cyclonic circulation to anticyclonic one and then back again to cyclonic type of circulation as the B-K sea ice concentration gradually reduces from 100% to ice free conditions. We present a conceptual model that may explain the nonlinear local atmospheric response in the B-K seas region by counter play between convection over the surface heat source and baroclinic effect due to modified temperature gradients in the vicinity of the heating area.

  9. Risk factors of postoperative complications after radical cystectomy with continent or conduit urinary diversion in Armenia.

    PubMed

    Tsaturyan, Arman; Petrosyan, Varduhi; Crape, Byron; Sahakyan, Yeva; Abrahamyan, Lusine

    2016-01-01

    To estimate the surgical volume and the incidence of in-hospital complications of RC in Armenia from 2005 to 2012, and to investigate potential risk factors of complications. The study utilized a retrospective chart review in a cohort of patients who had RC followed by either continent or conduit urinary diversion in all hospitals of Armenia from 2005 to 2012. A detailed chart review was conducted abstracting information on baseline demographic and clinical characteristics, surgical procedural details, postoperative management and in-hospital complications. Multivariable logistic regression analysis was applied to estimate the independent risk factors for developing 'any postoperative complication'. The total study sample included 273 patients (mean age = 58.5 years, 93.4 % men). Overall, 28.9 % (n = 79) of patients had at least one in-hospital complication. The hospital mortality rate was 4.8 % (n = 13). The most frequent types of complications were wound-related (10.3 %), gastrointestinal (9.2 %) and infectious (7.0 %). The ischemic heart disease (OR = 3.3, 95 % CI 1.5-7.4), perioperative transfusion (OR = 2.0, 1.1-3.6), glucose level [OR = 0.71 (0.63-0.95)], and hospital type (OR = 2.3, 95 % CI 1.1-4.7) were independent predictors of postoperative complications. The rate of RC complications in Armenia was similar to those observed in other countries. Future prospective studies should evaluate the effect of RC complications on long-term outcomes and costs in Armenia. Policy recommendations should address the issues regarding surgeon training and hospital volume to decrease the risk of RC complications. PMID:26933633

  10. Bacteria Community in the Terrestrial Deep Subsurface Microbiology Research of the Chinese Continent Scientific Drilling

    NASA Astrophysics Data System (ADS)

    Wang, Y.; Xia, Y.; Dong, H.; Dong, X.; Yang, K.; Dong, Z.; Huang, L.

    2005-12-01

    Microbial communities in the deep drill cores from the Chinese Continent Scientific Drilling were analyzed with culture-independent and dependent techniques. Genomic DNA was extracted from two metamorphic rocks: S1 from 430 and S13 from 1033 meters below the ground surface. The 16S rRNA gene was amplified by polymerase chain reaction (PCR) followed by cloning and sequencing. The total cell number was counted using the 4',6-diamidino-2-phenylindole (DAPI) staining and biomass of two specific bacteria were quantified using real-time PCR. Enrichment was set up for a rock from 3911 meters below the surface in medium for authotrophic methanogens (i.e., CO2 + H2). The total cell number in S13 was 1.0 × 104 cells per gram of rock. 16S rRNA gene analysis indicated that low G + C Gram positive sequences were dominant (50 percent of all 54 clone sequenced) followed by the alpha-, beta, and gamma-Proteobacteria. Within the low G + C Gram positive bacteria, most clone sequences were similar to species of Bacillus from various natural environments (deserts, rivers etc.). Within the Proteobacteria, our clone sequences were similar to species of Acinetobacter, Acidovorax, and Aeromonas. The RT-RCP results showed that biomass of two particular clone sequences (CCSD1305, similar to Aeromonas caviae and CCSD1307, similar to Acidovorax facilis) was 95 and 1258 cells/g, respectively. A bacterial isolate was obtained from the 3911-m rock in methanogenic medium. It was Gram negative with no flagella, immobile, and facultative anaerobic, and grows optimally at 65oC. Phylogenetic analysis indicated that it was closely related to the genus of Bacillus. Physiological tests further revealed that it was a strain of Bacillus caldotenax.

  11. Tiny worms from a mighty continent: high diversity and new phylogenetic lineages of African monogeneans.

    PubMed

    Přikrylová, Iva; Vanhove, Maarten P M; Janssens, Steven B; Billeter, Paul A; Huyse, Tine

    2013-04-01

    The family Gyrodactylidae contains one of the most significant radiations of platyhelminth fish parasites. The so-called hyperviviparity is very rare in the animal kingdom, and the rapid generation time can lead to an explosive population growth, which can cause massive losses in farmed fish. Here we present the first molecular phylogeny including all-but-one African genera, inferred from ITS and 18S rDNA sequences. The validity of nominal genera is discussed in relation to the systematic value of morphological characters traditionally used for generic identification. New complete 18S rDNA sequences of 18 gyrodactylid species of eight genera together with ITS rDNA gene sequences of eight species representing seven genera were generated and complemented with GenBank sequences. The maximum likelihood and Bayesian analyses pointed to a paraphyletic nature of African Gyrodactylus species. They formed well-supported clades possibly indicating speciation within host taxa: (1) parasites of cichlids (Cichlidae); (2) parasites of catfishes (Siluriformes), consisting of a lineage infecting mochokids and one infecting clariids. Macrogyrodactylus spp. firmly clustered into a monophyletic group. We found that Swingleus and Fundulotrema are very closely related and clearly cluster within Gyrodactylus. This supports earlier claims as to the paraphyly of the nominal genus Gyrodactylus as it is currently defined, and necessitates a revision of Swingleus and Fundulotrema. Molecular dating estimates confirmed a relatively young, certainly post-Gondwanan, origin of gyrodactylid lineages. Building on the previously suggested South-American origin of viviparous gyrodactylids, the dataset suggests subsequent intercontinental dispersal to Africa and from there repeated colonisation of the Holarctic. Even though the African continent has been heavily under sampled, the present diversity is far greater than in the intensively studied European fauna, probably because of the high endemicity

  12. Big Data and Ecological Forecasting: Integrating NEON Observational and Sensor Data from Reach to Continent

    NASA Astrophysics Data System (ADS)

    Vance, J. M.; Goodman, K. J.; Lunch, C. K.; Fitzgerald, M.

    2015-12-01

    The ability to forecast the response of varied ecosystems to changes in climate and land use will be crucial for the management of resources and ecosystem services. Ecological forecasting presents many significant challenges within each of the aspects of data capture, assimilation, and modeling. High space-time resolution sampling is required to address the challenges of scaling from the site level to the continent. Determining the uncertainty of data used for model input and parameterization is critical for constraining the model for accurate representation. The National Ecological Observatory Network (NEON) is poised to greatly expand the scale and availability of biogeochemical and aquatic ecological data. NEON is a continental-scale facility designed to collect and disseminate data that addresses the impacts of climate change, land-use, and invasive species on ecosystem structure and function. Using a combination of standardized observational sampling and sensor measurements, NEON will provide a rich source of biogeochemical and biophysical data from 34 aquatic and 47 terrestrial sites spatially distributed across the US, including Alaska, Hawaii and Puerto Rico for 30 years. Sites were selected to be representative of major ecosystems and maximize scalability. In addition to standardizing measurements, NEON is determining the quantitative uncertainty of each data product making them well suited to constrain models. NEON aquatic data will not only serve to baseline aquatic ecology in major ecosystems but also presents opportunities to bolster Hydrologic Models as well as incorporate aquatic biogeochemical cycling into Land Surface Models. Here we present examples of published and provisional data currently available from deployed aquatic sites, as well as an overview of the full scope and release schedule of the open source ecological data to be published on the NEON web portal. Several use cases, such as whole stream metabolism, groundwater exchange, high

  13. Local feedback mechanisms of the shallow water region around the Maritime Continent

    NASA Astrophysics Data System (ADS)

    Xue, Pengfei; Eltahir, Elfatih A. B.; Malanotte-Rizzoli, Paola; Wei, Jun

    2014-10-01

    The focus of this study is the local-scale air-sea feedback mechanisms over the shallow shelf water region (water depth <200 m) of the Maritime Continent (MC). MC was selected as a pilot study site for its extensive shallow water coverage, geographic complexity, and importance in the global climate system. To identify the local-scale air-sea feedback processes, we ran numerical experiments with perturbed surface layer water temperature using a coupled ocean-atmosphere model and an uncoupled ocean model. By examining the responses of the coupled and uncoupled models to the water temperature perturbation, we identify that, at a local-scale, a negative feedback process through the coupled dynamics that tends to restore the SST from its perturbation could dominate the shallow water region of the MC at a short time scale of several days. The energy budget shows that 38% of initial perturbation-induced heat energy was adjusted through the air-sea feedback mechanisms within 2 weeks, of which 58% is directly transferred into the atmosphere by the adjustment of latent heat flux due to the evaporative cooling mechanism. The increased inputs of heat and moisture into the lower atmosphere then modifies its thermal structure and increases the formation of low-level clouds, which act as a shield preventing incoming solar radiation from reaching the sea surface, accounts for 38% of the total adjustment of surface heat fluxes, serving as the second mechanism for the negative feedback process. The adjustment of sensible heat flux and net longwave radiation play a secondary role. The response of the coupled system to the SST perturbation suggests a response time scale of the coupled feedback process of about 3-5 days. The two-way air-sea feedback tightly links the surface heat fluxes, clouds and SST, and can play an important role in regulating the short-term variability of the SST over the shallow shelf water regions.

  14. Benchmark map of forest carbon stocks in tropical regions across three continents

    PubMed Central

    Saatchi, Sassan S.; Harris, Nancy L.; Brown, Sandra; Lefsky, Michael; Mitchard, Edward T. A.; Salas, William; Zutta, Brian R.; Buermann, Wolfgang; Lewis, Simon L.; Hagen, Stephen; Petrova, Silvia; White, Lee; Silman, Miles; Morel, Alexandra

    2011-01-01

    Developing countries are required to produce robust estimates of forest carbon stocks for successful implementation of climate change mitigation policies related to reducing emissions from deforestation and degradation (REDD). Here we present a “benchmark” map of biomass carbon stocks over 2.5 billion ha of forests on three continents, encompassing all tropical forests, for the early 2000s, which will be invaluable for REDD assessments at both project and national scales. We mapped the total carbon stock in live biomass (above- and belowground), using a combination of data from 4,079 in situ inventory plots and satellite light detection and ranging (Lidar) samples of forest structure to estimate carbon storage, plus optical and microwave imagery (1-km resolution) to extrapolate over the landscape. The total biomass carbon stock of forests in the study region is estimated to be 247 Gt C, with 193 Gt C stored aboveground and 54 Gt C stored belowground in roots. Forests in Latin America, sub-Saharan Africa, and Southeast Asia accounted for 49%, 25%, and 26% of the total stock, respectively. By analyzing the errors propagated through the estimation process, uncertainty at the pixel level (100 ha) ranged from ±6% to ±53%, but was constrained at the typical project (10,000 ha) and national (>1,000,000 ha) scales at ca. ±5% and ca. ±1%, respectively. The benchmark map illustrates regional patterns and provides methodologically comparable estimates of carbon stocks for 75 developing countries where previous assessments were either poor or incomplete. PMID:21628575

  15. Benchmark map of forest carbon stocks in tropical regions across three continents.

    PubMed

    Saatchi, Sassan S; Harris, Nancy L; Brown, Sandra; Lefsky, Michael; Mitchard, Edward T A; Salas, William; Zutta, Brian R; Buermann, Wolfgang; Lewis, Simon L; Hagen, Stephen; Petrova, Silvia; White, Lee; Silman, Miles; Morel, Alexandra

    2011-06-14

    Developing countries are required to produce robust estimates of forest carbon stocks for successful implementation of climate change mitigation policies related to reducing emissions from deforestation and degradation (REDD). Here we present a "benchmark" map of biomass carbon stocks over 2.5 billion ha of forests on three continents, encompassing all tropical forests, for the early 2000s, which will be invaluable for REDD assessments at both project and national scales. We mapped the total carbon stock in live biomass (above- and belowground), using a combination of data from 4,079 in situ inventory plots and satellite light detection and ranging (Lidar) samples of forest structure to estimate carbon storage, plus optical and microwave imagery (1-km resolution) to extrapolate over the landscape. The total biomass carbon stock of forests in the study region is estimated to be 247 Gt C, with 193 Gt C stored aboveground and 54 Gt C stored belowground in roots. Forests in Latin America, sub-Saharan Africa, and Southeast Asia accounted for 49%, 25%, and 26% of the total stock, respectively. By analyzing the errors propagated through the estimation process, uncertainty at the pixel level (100 ha) ranged from ± 6% to ± 53%, but was constrained at the typical project (10,000 ha) and national (>1,000,000 ha) scales at ca. ± 5% and ca. ± 1%, respectively. The benchmark map illustrates regional patterns and provides methodologically comparable estimates of carbon stocks for 75 developing countries where previous assessments were either poor or incomplete. PMID:21628575

  16. Precipitation over urban areas in the western Maritime Continent using a convection-permitting model

    NASA Astrophysics Data System (ADS)

    Argüeso, Daniel; Di Luca, Alejandro; Evans, Jason P.

    2015-11-01

    This study investigates the effects of urban areas on precipitation in the western Maritime Continent using a convection-permitting regional atmospheric model. The Weather Research and Forecasting model was used to simulate the atmosphere at a range of spatial resolutions using a multiple nesting approach. Two experiments (with and without urban areas) were completed over a 5-year period (2008-2012) each to estimate the contribution of cities to changes in local circulation. At first, the model is evaluated against two satellite-derived precipitation products and the benefit of using a very high-resolution model (2-km grid spacing) over a region where rainfall is dominated by convective processes is demonstrated, particularly in terms of its diurnal cycle phase and amplitude. The influence of cities on precipitation characteristics is quantified for two major urban nuclei in the region (Jakarta and Kuala Lumpur) and results indicate that their presence locally enhances precipitation by over 30 %. This increase is mainly due to an intensification of the diurnal cycle. We analyse the impact on temperature, humidity and wind to put forward physical mechanisms that explain such changes. Cities increase near surface temperature, generating instability. They also make land-sea temperature contrasts stronger, which enhances sea breeze circulations. Together, they increase near-surface moisture flux convergence and favour convective processes leading to an overall increase of precipitation over urban areas. The diurnal cycle of these effects is reflected in the atmospheric footprint of cities on variables such as humidity and cloud mixing ratio and accompanies changes in precipitation.

  17. Crustal structure of the Caribbean-northeastern South America arc-continent collision zone

    NASA Astrophysics Data System (ADS)

    Christeson, Gail L.; Mann, Paul; Escalona, Alejandro; Aitken, Trevor J.

    2008-08-01

    We present the results of a 568-km-long regional wide-angle seismic profile conducted in the southeastern Caribbean that crosses an active island arc, a remnant arc, two basins possibly floored by oceanic crust, an allochthonous terrane of forearc affinity, and the passive margin of northern South America. The velocity structures of the Late Cretaceous Aves Ridge remnant arc and Miocene and younger Lesser Antilles arc are remarkably similar, which implies that magmatic processes have remained moderately steady over time. Crustal thickness is ˜26 km at the Aves Ridge and ˜24 km at the Lesser Antilles arc. In comparison to the Izu-Bonin and Aleutian arcs, the Lesser Antilles arc is thinner and has no evidence for a lower crustal cumulate layer, which is consistent with the estimated low magma production rates of the Lesser Antilles arc. Crustal thickness beneath the Grenada and Tobago basins is 4-10 km, and the velocity structure suggests that these basins could be floored by oceanic crust. A decrease of ˜1 km/s in average seismic velocity of the upper crust is observed from NW to SE across the North Coast fault zone; we argue that this marks the suture between the far-traveled Caribbean arc and the passive margin of the South American continent. Current strike-slip motion between the Caribbean and South American plates is located ˜30 km to the south, and thus material originally deposited on the South American passive margin has now been transferred to the Caribbean plate.

  18. Simulated versus observed patterns of warming over the extratropical Northern Hemisphere continents during the cold season.

    PubMed

    Wallace, John M; Fu, Qiang; Smoliak, Brian V; Lin, Pu; Johanson, Celeste M

    2012-09-01

    A suite of the historical simulations run with the Intergovernmental Panel on Climate Change Fourth Assessment Report (IPCC AR4) models forced by greenhouse gases, aerosols, stratospheric ozone depletion, and volcanic eruptions and a second suite of simulations forced by increasing CO(2) concentrations alone are compared with observations for the reference interval 1965-2000. Surface air temperature trends are disaggregated by boreal cold (November-April) versus warm (May-October) seasons and by high latitude northern (N: 40°-90 °N) versus southern (S: 60 °S-40 °N) domains. A dynamical adjustment is applied to remove the component of the cold-season surface air temperature trends (over land areas poleward of 40 °N) that are attributable to changing atmospheric circulation patterns. The model simulations do not simulate the full extent of the wintertime warming over the high-latitude Northern Hemisphere continents during the later 20th century, much of which was dynamically induced. Expressed as fractions of the concurrent trend in global-mean sea surface temperature, the relative magnitude of the dynamically induced wintertime warming over domain N in the observations, the simulations with multiple forcings, and the runs forced by the buildup of greenhouse gases only is 721, and roughly comparable to the relative magnitude of the concurrent sea-level pressure trends. These results support the notion that the enhanced wintertime warming over high northern latitudes from 1965 to 2000 was mainly a reflection of unforced variability of the coupled climate system. Some of the simulations exhibit an enhancement of the warming along the Arctic coast, suggestive of exaggerated feedbacks. PMID:22847408

  19. Continent-arc collision in the Banda Arc imaged by ambient noise tomography

    NASA Astrophysics Data System (ADS)

    Porritt, Robert W.; Miller, Meghan S.; O'Driscoll, Leland J.; Harris, Cooper W.; Roosmawati, Nova; Teofilo da Costa, Luis

    2016-09-01

    The tectonic configuration of the Banda region in southeast Asia captures the spatial transition from subduction of Indian Ocean lithosphere to subduction and collision of the Australian continental lithosphere beneath the Banda Arc. An ongoing broadband seismic deployment funded by NSF is aimed at better understanding the mantle and lithospheric structure in the region and the relationship of the arc-continent collision to orogenesis. Here, we present results from ambient noise tomography in the region utilizing this temporary deployment of 30 broadband instruments and 39 permanent stations in Indonesia, Timor Leste, and Australia. We measure dispersion curves for over 21,000 inter-station paths resulting in good recovery of the velocity structure of the crust and upper mantle beneath the Savu Sea, Timor Leste, and the Nusa Tenggara Timur (NTT) region of Indonesia. The resulting three dimensional model indicates up to ∼25% variation in shear velocity throughout the plate boundary region; first-order velocity anomalies are associated with the subducting oceanic lithosphere, subducted Australian continental lithosphere, obducted oceanic sediments forming the core of the island of Timor, and high velocity anomalies in the Savu Sea and Sumba. The structure in Sumba and the Savu Sea is consistent with an uplifting forearc sliver. Beneath the island of Timor, we confirm earlier inferences of pervasive crustal duplexing from surface mapping, and establish a link to underlying structural features in the lowermost crust and uppermost mantle that drive upper crustal shortening. Finally, our images of the volcanic arc under Flores, Wetar, and Alor show high velocity structures of the Banda Terrane, but also a clear low velocity anomaly at the transition between subduction of oceanic and continental lithosphere. Given that the footprint of the Banda Terrane has previously been poorly defined, this model provides important constraints on tectonic reconstructions that

  20. Quality of life related to urinary continence in adult spina bifida patients

    PubMed Central

    Dong, Caroline; Casey, Jessica T.; Greiman, Alyssa; Mukherjee, Shubhra; Kielb, Stephanie J.

    2015-01-01

    Introduction To analyze the correlations of bladder management technique, ambulatory status and urologic reconstruction on quality of life (QOL) as affected by urinary symptoms in adult spina bifida (SB) patients. Material and methods Sixty–six adult SB patients completed the RAND 36–Item Health Survey (mSF–36) and Incontinence Quality of Life (I–QOL). Demographic information, history of urinary reconstruction, and bladder management techniques were reviewed and analyzed with respect to survey scores. Results Mean age of patients was 32.3 (SD ±7.2) years and 44 patients (66.7%) were female. Forty–five patients (68.2%) were mainly ambulatory, 21 (31.8%) use a wheelchair and 10 (15.2%) had urologic reconstruction, while 56 (83.3%) did not. Twelve patients (18.2%) void, 42 (63.6%) perform clean intermittent catheterization (CIC), 4 (6.1%) use an indwelling catheter, 3 (4.5%) have an ileal conduit (IC) and 5 (7.6%) mainly use diapers. Mean mSF–36 General Health score was 56.5 (SD ±22.9) and mean I–QOL Sum score was 50.9 (SD ±21.7), where lower scores reflect lower QOL. mSF–36 and I–QOL scores did not significantly correlate with bladder management technique, ambulatory status or urologic reconstruction. A correlation was noted between I–QOL scales and most mSF–36 scales (all p <0.02). Conclusions In our cohort study of adult SB patients, bladder management technique and urologic reconstruction did not correlate with urinary (I–QOL) or general health (mSF–36) domains, although I–QOL and mSF–36 scores correlated closely, suggesting urinary continence is significantly related to general QOL. However, we are unable to identify a single factor that improves either urinary or general QOL. PMID:25914840

  1. The Ocean-Continent Transition at the North Atlantic Volcanic Margins

    NASA Astrophysics Data System (ADS)

    White, R. S.; Christie, P. A.; Kusznir, N. J.; Roberts, A. M.; Eccles, J.; Lunnon, Z.; Parkin, C. J.; Smith, L. K.; Spitzer, R.; Roberts, A. W.

    2005-05-01

    The continental margins of the northern North Atlantic are the best studied volcanic margins in the world. There is a wealth of integrated wide-angle and deep seismic profiles across the continent-ocean transition and the adjacent oceanic and continental crust, several of which form conjugate margin studies. We show new results from the integrated Seismic Imaging and Modelling of Margins (iSIMM) profiles across the Faroes continental margin which image both the extruded volcanics which generate seaward dipping reflector sequences and the underlying lower-crustal intrusions from which the extruded basalts are fed. This enables estimation of the degree of continental stretching and the total volume of melt generated from the mantle at the time of continental breakup. The new results are set in the context of profiles along the entire northern North Atlantic margins. The pattern of melt generation during continental breakup and the initiation of seafloor spreading allows us to map the pattern of enhanced sub-lithospheric mantle temperatures caused by initiation of the Iceland mantle plume over this period. The initial mantle plume thermal anomalies have the shape of rising hot sheets of mantle up to 2000 km in length, which focus into a more axisymmetric shape under the present location of Iceland. These spatial and temporal variations in the mantle temperature exert important controls on the history of uplift and subsidence and thermal maturation of the sediments near the continental margin and its hinterland. The iSIMM Scientific Team comprises NJ Kusznir, RS White, AM Roberts, PAF Christie, R Spitzer, N Hurst, ZC Lunnon, CJ Parkin, AW Roberts, LK Smith, V Tymms, J Eccles and D Healy. The iSIMM project is supported by Liverpool and Cambridge Universities, Schlumberger Cambridge Research, Badley Technology Limited, WesternGeco, Amerada Hess, Anadarko, BP, ConocoPhillips, ENI-UK, Statoil, Shell, the NERC and DTI. We thank WesternGeco for provision of Q-streamer data.

  2. Northern Papua New Guinea: Structure and sedimentation in a modern arc-continent collision

    SciTech Connect

    Abbott, L.; Silver, E. )

    1990-05-01

    Northern Papua New Guinea and the Solomon Sea are the site of a modern oblique, arc-continent collision, which is progressing from northwest to southeast. By combining offshore seismic data from the Solomon Sea with geologic mapping in the Markham Valley area of northern Papua New Guinea the authors are predicting the outcome of this collision. The Huon Gulf is the present site of initial collision. Seismic profiles show this area is dominated by thin thrust sheets. Onshore, the bulk of the uplifted accretionary wedge is a melange with exotic blocks of a variety of lithologies. Structurally below the melange lies the Leron Formation composed of thick channelized sandstone and conglomerate. It dips north at approximately 40{degree} and is cut by several thrust fault with associated folds. Limestone blocks within the melange are reported to be 2 Ma, and Beryllium 10 anomalies from Bismarck arc volcanoes suggest that initial collision of the Finisterre block (375 km northwest of the present collision point) began no earlier than 3 Ma. This implies the collision is propagating laterally at about 125 km/m.y.. Large outcrops of basalt and gabbro within the melange suggest that segments of oceanic crust were incorporated into the accretionary wedge. Modern sedimentation within the collision zone grades from fluvial sediments in the Markham Valley to deep-water turbidites ponded behind a structural ridge near the point of incipient collision. The Markham submarine canyon occupies the collision front here, and efficiently erodes the accretionary wedge. This setting may serve as a modem analog for deposition of much of the Leron Formation which exhibits tremendous sediment reworking.

  3. Age relationships for magmatic units of Mid-Continent rift system

    SciTech Connect

    Van Schmus, W.R.

    1989-03-01

    K-Ar ages ranging from about 600 to 1000 Ma have recently been reported for gabbro and basalt recovered from the Texaco 1 Poersch well in Kansas. This has prompted suggestions that rift magmatism there may be distinctly younger than that in the Lake Superior region, and that development of the rift may have lasted several hundred million years. Review of ages from Keweenawan volcanic and plutonic rocks in the Lake Superior region shows that the best results are obtained from U-Pb analyses of zircon and baddeleyite; recent published results range from 1087 to 1108 Ma, with uncertainties on individual ages of /plus minus/ 4 m.y. This finding is consistent with earlier reported U-Pb zircon results. Virtually all other techniques are susceptible to geologic error and generally yield ages of significant less than 1100 Ma. The reliability decreases approximately in the sequence Rb-Sr (whole rock), K-Ar (biotite), Ar/sup 39/-Ar/sup 40/ (whole rock), K-Ar (whole rock), with fresh, coarse-grained plutonic rocks yielding older ages than altered, fine-grained volcanic rocks. K-Ar data on altered, fine-grained mafic rocks, therefore, are very poor indicators of original crystallization ages. Since the rocks from the Texaco 1 Poersch well are fine grained and slightly to moderately altered, their true ages are probably substantially older than 800-900 Ma. Interpretations based on the K-Ar ages from this well are ill advised; tectonic interpretation of the Mid-Continent rift system must wait for more accurate results. Several possibilities exist for obtaining more reliable ages from samples of the Poersch well and other, older wells in the region. These studies are in progress, and any available results will be presented.

  4. Preparation of northern mid-continent petroleum. Quarterly report, July 1--September 20, 1996

    SciTech Connect

    Gerhard, L.C.; Carr, T.R.; Watney, W.L.

    1997-04-01

    Project will develop a prototype for a digital and hard-copy atlas of petroleum fields and reservoirs in the northern Mid-continent region. A limited number of reservoirs in Kansas are to be included in the prototype project,but the goal is to expand beyond the prototype atlas to include significant reservoirs representing the major plays in Kansas, Nebraska, south dakota, North Dakota, the Williston basin portion of Montana, the Denver-Julesburg basin of eastern Colorado and southeastern Colorado. Primary products of the prototype atlas will be on-line accessible digital data bases covering two selected petroleum plays in Kansas. ``Pages`` and data schema for the atlas overview and field studies have been developed and are accessible through the world-wide-web. The atlas structure includes access to geologic, geophysical and production information at levels from the national, to the regional, to the field to the individual well. Several approaches have been developed that provide efficient and flexible screening and search procedures. The prototype of the digital atlas is accessible through the Kansas Geological Survey Petroleum Research Section (PRS) HomePage (the Universal Resource Locator [URL] is http://www.kgs.ukans.edu/PRS/PRS.html). The Digital Petroleum Atlas (DPA) HomePage is available directly at http://www.kgs. ukans.edu/DPA/dpaHome.html. Technology transfer is underway through presentations at national and regional meetings and through the use of monthly electronic updates and the on-line availability of the DPA products. Project information and Quarterly Progress Reports are linked to the Digital Petroleum Atlas HomePage.

  5. Mesoscale modeling of smoke transport over the South Asian maritime continent: vertical distributions and topographic effect

    NASA Astrophysics Data System (ADS)

    Ge, C.; Wang, J.; Yang, Z.; Hyer, E. J.; Reid, J. S.; Chew, B.; Mahamod, M.

    2011-12-01

    The online-coupled Weather Research and Forecasting model with Chemistry (WRF-Chem) is used in conjunction with the FLAMBE MODIS-based biomass burning emissions to simulate the transport of smoke particles over the southeast Asian Maritime Continent (MC, 10°S - 10°N, 90°E-150°E) during September - October 2006 when the moderate El Nino event caused the largest region biomass burning outbreak since 1998. The modeled smoke transport pathway is found to be consistent with the MODIS true color images. Quantitatively, the modeled smoke particle mass can explain ~50% of temporal variability in 24-hour average observed PM10 at most ground stations, with linear correlation coefficients often larger than 0.7. Analysis of CALIOP data shows that smoke aerosols are primarily located within 3.5 km above the surface, and we found that smoke injection height in the model should be at ~800 m above surface to best match CALIOP observations downwind, instead of 2 km as used in the past literature. Comparison of CALIOP data in October 2006 with that in other years (2007-2010) reveals that the peak of aerosol extinction always occurs at ~1 km above surface, but smoke events in 2006 doubled the aerosol extinction from the surface to 3.5 km. Numerical experiments further show that the Tama Abu topography in Malaysia Peninsula has a significant impact on smoke transport and the surface in the vicinity. A conceptual model, based upon our analysis of two-month WRFchem simulation and satellite data, is proposed to explain the meteorological causes for smoke layers above the clouds as seen in the CALIOP data.

  6. Study protocol: ICONS: Identifying continence options after stroke: A randomised trial

    PubMed Central

    2011-01-01

    Background Urinary incontinence following acute stroke is common, affecting between 40%-60% of people in hospital after a stroke. Despite the availability of clinical guidelines for urinary incontinence and urinary incontinence after stroke, national audit data suggest incontinence is often poorly managed. Conservative interventions (e.g. bladder training, pelvic floor muscle training and prompted voiding) have been shown to have some effect with participants in Cochrane systematic reviews, but have not had their effectiveness demonstrated with stroke patients. Methods/Design A cluster randomised controlled pilot trial designed to assess the feasibility of a full-scale cluster randomised trial and to provide preliminary evidence of the effectiveness and cost-effectiveness of a systematic voiding programme for the management of continence after stroke. Stroke services will be randomised to receive the systematic voiding programme, the systematic voiding programme plus supported implementation, or usual care. The trial aims to recruit at least 780 participants in 12 stroke services (4 per arm). The primary outcome is presence/absence of incontinence at six weeks post-stroke. Secondary outcomes include frequency and severity of incontinence, quality of life and cost-utility. Outcomes will be measured at six weeks, three months and (for participants recruited in the first three months) twelve months after stroke. Process data will include rates of recruitment and retention and fidelity of intervention delivery. An integrated qualitative evaluation will be conducted in order to describe implementation and assist in explaining the potential mediators and modifiers of the process. Trial Registration ISRCTN: ISRCTN08609907 PMID:21599945

  7. The continent-ocean transition at the northern margin of the South China Sea

    NASA Astrophysics Data System (ADS)

    Gao, J.; Wu, S.; McIntosh, K. D.; Mi, L.; Yao, B.; Chen, Z.; Jia, L.

    2014-12-01

    The northern margin of the South China Sea (SCS) has particular characteristics compared with typical passive margins. Several tectonic movements and volcanic activities have happened in the SCS and resulted in diverse structures along its northern margin. Based on several crustal-scale, high-resolution, multi-channel seismic reflection profiles and satellite gravity data across the northern SCS margin, this paper analyses the structures, volcanoes and deep crust of the continent-ocean transition zone (COT) at the mid-northern margin of the SCS to study the pattern and extension model of the SCS. Gravity modelling revealed that a stepped crustal thinning occurs across the COT and a High Velocity Layer (HVL) with 0.8-6 km thick is located in the slope below the lower crust. Results show that the COT close to the Dongsha uplift is characterized by a syn-rift depression and structural highs with igneous rocks bounded by seamounts seaward. Farther west, the COT shows a zone including syn-rift depressions, structural high with igneous sills, volcanic zone, and tilted fault blocks bounded by normal fault seaward. Reflector T60 may represent an important unconformity in Pearl River Mouth Basin indicating a delayed rift in the northern SCS margin related to a ridge jump in 23.8 Ma. Our study delineates an extent of HVL just located in the eastern portion of the northern SCS margin based on the geophysical data. The non-coupling of the spatial extent between HVL and COT shows that the HVL may not be a necessary sign of the COT at the northern SCS margin. The magmatic intrusions and HVL may result from post-rifting underplating due to the partial melting from lithospheric extension and the passive mantle/asthenospheric upwelling. This study proposed an intermediate rifting mode to explain the mid-northern margin of the SCS which is closer to the magma-poor margins than volcanic margins.

  8. Electromagnetic Subsurface Soundings at HF frequencies and Antenna Impedance Measurements on the Antarctic Continent

    NASA Astrophysics Data System (ADS)

    Valerie, C.; Jean-Jacques, B.; Richard, N.; Michel, H.; Sebastien, B.; Francois, D.; Alain, R.

    2004-05-01

    In the frame of the NETLANDER project, a ground penetrating radar (GPR) dedicated to the exploration of the Martian subsurface has been developed. This GPR is designed for deep sounding down to a depth which is sufficient to allow possible detection of liquid water and thus operates mainly at a frequency of 2 MHz. Contrary to the normal mode of operation of subsurface radars which can be moved over the soil to be explored, the GPR of NETLANDER aims at performing 3D imaging of the underground reflecting structures even if it operates in a fixed position. This is achieved by retrieving not only the distance of the reflectors but also the direction of the backscattered waves by measuring the 2 horizontal electric components and the 3 magnetic components of the reflected waves. Two perpendicular dipoles each consisting in two 35-meters electric monopoles are used for both transmission and reception, while the receiving magnetic antenna can be successively directed along 3 mutually orthogonal directions. In addition, the perfect stability of the environment allows a very large number of coherent integrations to be performed, which provide a satisfactory sensitivity Ground tests were recently carried out on the Antarctic continent in 2004. Soundings at frequencies in the range 2-5 MHz have been performed with the NETLANDER monostatic GPR prototype and with the updated version of this instrument, which operates in a real bistatic mode. As expected the echoes due to interaction with the bedrock are detected and the magnetic component measurements provide information linked to the orientation of the reflecting structures. The first experimental results will be reported. We will present results on the electric antenna impedance measurements, which give information on the permittivity of the upper subsurface layer. We will also focus on the analysis of the backscattered signals using both electric and magnetic components of the received field. Comparisons with numerical

  9. Accretionary complex structure and kinematics during Paleozoic arc continent collision in the southern Urals

    NASA Astrophysics Data System (ADS)

    Alvarez-Marron, J.; Brown, D.; Perez-Estaun, A.; Puchkov, V.; Gorozhanina, Y.

    2000-10-01

    The southern Urals contain a well-preserved accretionary complex that has overthrust the continental margin during arc-continent collision between the East European Craton (EEC) and the Magnitogorsk island arc in the Late Devonian. Within the accretionary complex, we study three tectonic units that differ in deformation style, and each provides a unique geodynamic implication. The Zilair Nappe, the largest and best exposed unit, consists of 5-6 km of syncollisional, arc-derived Upper Devonian to Lower Carboniferous polymictic and graywacke turbidites that were deposited across the continental margin and incorporated by frontal accretion into the accretionary complex. The Zilair Nappe is a bivergent thrust imbricate where the west-vergent thrusts dominate and have associated kilometer-scale ramp anticlines with well developed east-dipping axial planar cleavage. Along its eastern contact, however, the cleavage fans until it dips moderately westward and the folds are east-vergent. Following its emplacement, west-vergent, basement-involved thrusting that breached the whole accretionary complex imbricated the Zilair Nappe. The Timirovo Duplex is structurally beneath the Zilair Nappe, and outcrops for several tens of kilometers along its northwestern margin. The duplex forms a west-vergent thrust stack composed of a highly deformed and sheared Lower and Middle Devonian reef carbonates of the former EEC margin platform. These rocks were shallowly underplated at the base of the accretionary complex during emplacement over the margin. The Suvanyak Complex outcrops along the eastern contact of the Zilair Nappe, and consists of polydeformed greenschist facies metasediments of the former EEC slope that were offscraped, underplated and incorporated at the rear of the accretionary complex.

  10. SELECTION AND TREATMENT OF STRIPPER GAS WELLS FOR PRODUCTION ENHANCEMENT IN THE MID-CONTINENT

    SciTech Connect

    Scott Reeves

    2003-03-01

    Stripper gas wells are an important source of domestic energy supply and under constant threat of permanent loss (shut-in) due to marginal economics. In 1998, 192 thousand stripper gas wells produced over a Tcf of gas, at an average rate of less than 16 Mcfd. This represents about 57% of all producing gas wells in the onshore lower-48 states, yet only 8% of production. Reserves of stripper gas wells are estimated to be only 1.6 Tcf, or slightly over 1% of the onshore lower-48 total (end of year 1996 data). Obviously, stripper gas wells are at the very margin of economic sustenance. As the demand for natural gas in the U.S. grows to the forecasted estimate of over 30 Tcf annually by the year 2010, supply from current conventional sources is expected to decline. Therefore, an important need exists to fully exploit known domestic resources of natural gas, including those represented by stripper gas wells. The overall objectives of this project are to develop an efficient and low-cost methodology to broadly categorize the well performance characteristics for a stripper gas field, identify the high-potential candidate wells for remediation, and diagnose the specific causes for well underperformance. With this capability, stripper gas well operators can more efficiently and economically produce these resources and maximize these gas reserves. A further objective is to identify/develop, evaluate and test ''new and novel,'' economically viable remediation options. Finally, it is the objective of this project that all the methods and technologies developed in this project, while being tested in the Mid-Continent, be widely applicable to stripper gas wells of all types across the country. The project activities during the reporting period were: (1) The contract was signed on August 20, 2000. Little work has been performed other than preliminary planning to get the project underway.

  11. SELECTION AND TREATMENT OF STRIPPER GAS WELLS FOR PRODUCTION ENHANCEMENT IN THE MID-CONTINENT

    SciTech Connect

    Scott Reeves

    2003-04-01

    Stripper gas wells are an important source of domestic energy supply and under constant threat of permanent loss (shut-in) due to marginal economics. In 1998, 192 thousand stripper gas wells produced over a Tcf of gas, at an average rate of less than 16 Mcfd. This represents about 57% of all producing gas wells in the onshore lower-48 states, yet only 8% of production. Reserves of stripper gas wells are estimated to be only 1.6 Tcf, or slightly over 1% of the onshore lower-48 total (end of year 1996 data). Obviously, stripper gas wells are at the very margin of economic sustenance. As the demand for natural gas in the U.S. grows to the forecasted estimate of over 30 Tcf annually by the year 2010, supply from current conventional sources is expected to decline. Therefore, an important need exists to fully exploit known domestic resources of natural gas, including those represented by stripper gas wells. The overall objectives of this project are to develop an efficient and low-cost methodology to broadly categorize the well performance characteristics for a stripper gas field, identify the high-potential candidate wells for remediation, and diagnose the specific causes for well underperformance. With this capability, stripper gas well operators can more efficiently and economically produce these resources and maximize these gas reserves. A further objective is to identify/develop, evaluate and test ''new and novel,'' economically viable remediation options. Finally, it is the objective of this project that all the methods and technologies developed in this project, while being tested in the Mid-Continent, be widely applicable to stripper gas wells of all types across the country. The project activities during the reporting period were: Continued coordinating the final selection of candidates and field implementation with Oneok. Oneok plans on performing the operations early in 2003.

  12. SELECTION AND TREATMENT OF STRIPPER GAS WELLS FOR PRODUCTION ENHANCEMENT IN THE MID-CONTINENT

    SciTech Connect

    Scott Reeves

    2003-03-01

    Stripper gas wells are an important source of domestic energy supply and under constant threat of permanent loss (shut-in) due to marginal economics. In 1998, 192 thousand stripper gas wells produced over a Tcf of gas, at an average rate of less than 16 Mcfd. This represents about 57% of all producing gas wells in the onshore lower-48 states, yet only 8% of production. Reserves of stripper gas wells are estimated to be only 1.6 Tcf, or slightly over 1% of the onshore lower-48 total (end of year 1996 data). Obviously, stripper gas wells are at the very margin of economic sustenance. As the demand for natural gas in the U.S. grows to the forecasted estimate of over 30 Tcf annually by the year 2010, supply from current conventional sources is expected to decline. Therefore, an important need exists to fully exploit known domestic resources of natural gas, including those represented by stripper gas wells. The overall objectives of this project are to develop an efficient and low-cost methodology to broadly categorize the well performance characteristics for a stripper gas field, identify the high-potential candidate wells for remediation, and diagnose the specific causes for well underperformance. With this capability, stripper gas well operators can more efficiently and economically produce these resources and maximize these gas reserves. A further objective is to identify/develop, evaluate and test ''new and novel,'' economically viable remediation options. Finally, it is the objective of this project that all the methods and technologies developed in this project, while being tested in the Mid-Continent, be widely applicable to stripper gas wells of all types across the country. The project activities during the reporting period were: (1) Continued coordinating the final selection of candidates and field implementation with Oneok. Oneok plans on performing the operations early in 2003.

  13. SELECTION AND TREATMENT OF STRIPPER GAS WELLS FOR PRODUCTION ENHANCEMENT IN THE MID-CONTINENT

    SciTech Connect

    Scott Reeves

    2003-03-01

    Stripper gas wells are an important source of domestic energy supply and under constant threat of permanent loss (shut-in) due to marginal economics. In 1998, 192 thousand stripper gas wells produced over a Tcf of gas, at an average rate of less than 16 Mcfd. This represents about 57% of all producing gas wells in the onshore lower-48 states, yet only 8% of production. Reserves of stripper gas wells are estimated to be only 1.6 Tcf, or slightly over 1% of the onshore lower-48 total (end of year 1996 data). Obviously, stripper gas wells are at the very margin of economic sustenance. As the demand for natural gas in the U.S. grows to the forecasted estimate of over 30 Tcf annually by the year 2010, supply from current conventional sources is expected to decline. Therefore, an important need exists to fully exploit known domestic resources of natural gas, including those represented by stripper gas wells. The overall objectives of this project are to develop an efficient and low-cost methodology to broadly categorize the well performance characteristics for a stripper gas field, identify the high-potential candidate wells for remediation, and diagnose the specific causes for well underperformance. With this capability, stripper gas well operators can more efficiently and economically produce these resources and maximize these gas reserves. A further objective is to identify/develop, evaluate and test ''new and novel,'' economically viable remediation options. Finally, it is the objective of this project that all the methods and technologies developed in this project, while being tested in the Mid-Continent, be widely applicable to stripper gas wells of all types across the country. The project activities during the reporting period were: (1) Began preparing final project report, less the field implementation component. (2) Coordinated the final selection of candidates and field implementation with Oneok.

  14. Long-term Follow-up of Patients After Antegrade Continence Enema Procedure

    PubMed Central

    Siddiqui, Anees A.; Fishman, Steven J.; Bauer, Stuart B.; Nurko, Samuel

    2013-01-01

    Background Antegrade continence enema (ACE) has become an important therapeutic modality in the treatment of intractable constipation and fecal incontinence. There are little data available on the long-term performance of the ACE procedure in children. Methods A retrospective review of patients who underwent the ACE procedure was conducted. Irrigation characteristics and complications were noted. Outcome was assessed for individual encounters based on frequency of bowel movements, incontinence, pain, and predictability. Results One hundred seventeen patients underwent an ACE. One hundred five patients had at least 6 months of follow-up, and were included in the analysis. Diagnoses included myelodysplasia (39%), functional intractable constipation (26%), anorectal malformations (21%), nonrelaxing internal anal sphincter (7%), cerebral palsy (3%), and other diagnoses (4%). The average follow-up was 68 months (range 7–178 months). At the last follow-up, 69% of patients had successful bowel management. Of the 31% of patients who did not have successful bowel management, 20% were using the ACE despite suboptimal results, 10% required surgical removal, and 2% were not using the ACE because of behavioral opposition to it. Patients were started on normal saline, but were switched to GoLYTELY (PEG-3350 and electrolyte solution) if there was an inadequate response (61% at final encounter). Additives were needed in 34% of patients. The average irrigation dose was 23 ± 0.7mL/kg. The average toilet sitting time was 51.7 ± 3.5minutes, with infusions running for 12.1 ± 1.2minutes. Stomal complications occurred in 63% (infection, leakage, and stenosis) of patients, 33% required surgical revision and 6% eventually required diverting ostomies. Conclusions Long-term use of the ACE gives successful results in 69% of patients, whereas 63% had a stoma-related complication and 33% required surgical revision of the stoma. PMID:21502828

  15. Reconstructed and simulated temperature asymmetry between continents in both hemispheres over the last centuries

    NASA Astrophysics Data System (ADS)

    Goosse, Hugues

    2016-05-01

    Available proxy-based temperature reconstructions covering the past millennium display contrasted evolutions between the continents. The difference is particularly large between the two hemispheres. When driven by realistic natural and anthropogenic forcings, climate models tend to simulate a more spatially homogenous temperature response. This is associated with a relatively good agreement between model results and reconstructions in the Northern Hemisphere but a low consistency in the Southern Hemisphere. Here, simulations with data assimilations are performed to analyse the causes of this apparent disagreement. It shows that, when the uncertainties are taken into account, states of the climate system compatible with the forcing estimates, the reconstructions and the model physics can be obtained over the past millennium, except for the twentieth century in Antarctica where the simulated warming is always much larger than in the reconstructions. Such states consistent with all sources of information can be achieved even if the uncertainties of the reconstructions are underestimated. Although, well within the range of the proxy-based reconstructions, the temperatures obtained after data assimilation display more similar developments between the hemispheres than in those reconstructions. Ensuring the compatibility does not require to systematically reduce the model response to the forcing or to strongly enhance the model internal variability. From those results, there is thus no reason to suspect that the model is strongly biased in one aspect or another. The constraint imposed by the data assimilation is too low to unambiguously identify the origin of each feature displayed in the reconstructions but, as expected, changes in atmospheric circulation likely played a role in many of them. Furthermore, ocean heat uptake and release as well as oceanic heat transport are key elements to understand the delayed response of the Southern Hemisphere compared to the northern

  16. Interannual variations in snowpack in the Crown of the Continent Ecosystem

    NASA Astrophysics Data System (ADS)

    Selkowitz, David J.; Fagre, Daniel B.; Reardon, Blase A.

    2002-12-01

    Ecosystem changes such as glacier recession and alpine treeline advance have been documented over the previous 150 years in the Rocky Mountains of northern Montana and southern British Columbia and Alberta, a region known as the Crown of the Continent Ecosystem (CCE). Such changes are controlled, at least partially, by variations in snowpack. The CCE consists primarily of public lands, the majority of which is undeveloped or wilderness. Consequently, this region is well suited for an examination of long-term snowpack variation and associated ecosystem change. Data from nine SNOTEL sites provide an indication of the daily accumulation and ablation of snowpack over the period 1977-2001, as well as the relationship between precipitation, temperature and snowpack. 1 April data from 21 snow courses indicated the extent of regional snowpack variation and trends over the period 1950-2001, and 1 May data from three snow courses in Glacier National Park allow this record to be extended back to 1922. SNOTEL data suggest CCE snowpacks are larger and more persistent than in most regions of the western USA, and that water year precipitation is the primary control on 1 April snow water equivalent (SWE). Snow course data indicate that variations in both 1 April and 1 May mean SWE are closely tied to the Pacific decadal oscillation, an El Niño-southern oscillation-like interdecadal pattern of Pacific Ocean climate variability. Despite relatively stable snowpacks and summer temperatures since 1922, the glaciers in Glacier National Park have receded steadily during this period, implying a significant climatic shift between their Little Ice Age glacial maxima (ca 1860) and 1922. Published in 2002 by John Wiley & Sons Ltd.

  17. TRAC-MIP: Tropical Rain bands with an Annual cycle and Continent - Model Intercomparison Project.

    NASA Astrophysics Data System (ADS)

    Biasutti, Michela; Voigt, Aiko; Scheff, Jack; Zeppetello, Lucas Randall

    2016-04-01

    Understanding and modeling tropical rainfall has proven to be one of the most stubborn challenges in climate science. Tropical rainfall biases such as a double inter-tropical convergence zone (ITCZ) in the East Pacific have now persisted more than two decades despite the general improvements of climate models, and projections for the ITCZ and the monsoon systems remain uncertain in magnitude and sign. Progress in these areas can be fostered by a set of idealized experiments that target the dynamics of tropical rain band, as long as these simple experiments are properly integrated within a full hierarchy of model simulations. To this aim, we have designed the "Tropical Rain belts with an Annual cycle and Continent - Model Intercomparison Project." TRAC-MIP involves five experiments using idealized aquaplanet and land setups to explore the dynamics of tropical rainfall. By using interactive sea-surface temperatures and seasonally-varying insolation TRAC-MIP fills the gap between idealized aquaplanet simulations with prescribed SSTs and the fully-coupled realistic model simulations of CMIP5. TRAC-MIP includes the participation of 13 state-of-the art comprehensive climate models, and it also includes a simplified model that neglects cloud and water-vapor radiative feedbacks, thus allowing a more direct connection between the results from the TRAC-MIP comprehensive models and the theoretical studies of tropical rain belt dynamics. We will present preliminary results from the ensemble, aiming to examine the mechanisms controlling tropical precipitation in the context of forced variability. First and foremost, we are interested in the largest forced variation: the annual cycle. Second, we are interested in the response to key forcings of the future (greenhouse gases) and of the Holocene (insolation). We will draw out the similarities and the distinctions between oceanic and continental rain bands, study the ways in which the two interact with each other, and investigate

  18. Thermal evolution of the western South Atlantic and the adjacent continent during Termination 1

    NASA Astrophysics Data System (ADS)

    Chiessi, C. M.; Mulitza, S.; Mollenhauer, G.; Silva, J. B.; Groeneveld, J.; Prange, M.

    2015-06-01

    During Termination 1, millennial-scale weakening events of the Atlantic meridional overturning circulation (AMOC) supposedly produced major changes in sea surface temperatures (SSTs) of the western South Atlantic, and in mean air temperatures (MATs) over southeastern South America. It has been suggested, for instance, that the Brazil Current (BC) would strengthen (weaken) and the North Brazil Current (NBC) would weaken (strengthen) during slowdown (speed-up) events of the AMOC. This anti-phase pattern was claimed to be a necessary response to the decreased North Atlantic heat piracy during periods of weak AMOC. However, the thermal evolution of the western South Atlantic and the adjacent continent is so far largely unknown. Here we address this issue, presenting high-temporal-resolution SST and MAT records from the BC and southeastern South America, respectively. We identify a warming in the western South Atlantic during Heinrich Stadial 1 (HS1), which is followed first by a drop and then by increasing temperatures during the Bølling-Allerød, in phase with an existing SST record from the NBC. Additionally, a similar SST evolution is shown by a southernmost eastern South Atlantic record, suggesting a South Atlantic-wide pattern in SST evolution during most of Termination 1. Over southeastern South America, our MAT record shows a two-step increase during Termination 1, synchronous with atmospheric CO2 rise (i.e., during the second half of HS1 and during the Younger Dryas), and lagging abrupt SST changes by several thousand years. This delay corroborates the notion that the long duration of HS1 was fundamental in driving the Earth out of the last glacial.

  19. Thermal evolution of the western South Atlantic and the adjacent continent during Termination 1

    NASA Astrophysics Data System (ADS)

    Chiessi, C. M.; Mulitza, S.; Mollenhauer, G.; Silva, J. B.; Groeneveld, J.; Prange, M.

    2014-12-01

    During Termination 1, millennial-scale weakening events of the Atlantic meridional overturning circulation (AMOC) supposedly produced major changes in sea surface temperatures (SST) of the western South Atlantic, and in mean air temperatures (MAT) over southeastern South America. It was suggested, for instance, that the Brazil Current (BC) would strengthen (weaken) and the North Brazil Current (NBC) would weaken (strengthen) during slowdown (speed-up) events of the AMOC. This anti-phase pattern was claimed to be a necessary response to the decreased North Atlantic heat piracy during periods of weak AMOC. However, the thermal evolution of the western South Atlantic and the adjacent continent is largely unknown and a compelling record of the BC-NBC anti-phase behavior remains elusive. Here we address this issue, presenting high temporal resolution SST and MAT records from the BC and southeastern South America, respectively. We identify a warming in the western South Atlantic during Heinrich Stadial 1 (HS1), which is followed first by a drop and then by increasing temperatures during the Bølling-Allerød, in-phase with an existing NBC record. Additionally, a similar SST evolution is shown by a southernmost eastern South Atlantic record, suggesting a South Atlantic-wide pattern in SST evolution during most of Termination 1. Over southeastern South America, our MAT record shows a two-step increase during Termination 1, synchronous with atmospheric CO2 rise (i.e., during the second half of HS1 and during the Younger Dryas), and lagging abrupt SST changes by several thousand years. This delay corroborates the notion that the long duration of HS1 was fundamental to drive the Earth out of the last glacial.

  20. Precipitation over urban areas in the western Maritime Continent using a convection-permitting model

    NASA Astrophysics Data System (ADS)

    Argüeso, Daniel; Di Luca, Alejandro; Evans, Jason P.

    2016-08-01

    This study investigates the effects of urban areas on precipitation in the western Maritime Continent using a convection-permitting regional atmospheric model. The Weather Research and Forecasting model was used to simulate the atmosphere at a range of spatial resolutions using a multiple nesting approach. Two experiments (with and without urban areas) were completed over a 5-year period (2008-2012) each to estimate the contribution of cities to changes in local circulation. At first, the model is evaluated against two satellite-derived precipitation products and the benefit of using a very high-resolution model (2-km grid spacing) over a region where rainfall is dominated by convective processes is demonstrated, particularly in terms of its diurnal cycle phase and amplitude. The influence of cities on precipitation characteristics is quantified for two major urban nuclei in the region (Jakarta and Kuala Lumpur) and results indicate that their presence locally enhances precipitation by over 30 %. This increase is mainly due to an intensification of the diurnal cycle. We analyse the impact on temperature, humidity and wind to put forward physical mechanisms that explain such changes. Cities increase near surface temperature, generating instability. They also make land-sea temperature contrasts stronger, which enhances sea breeze circulations. Together, they increase near-surface moisture flux convergence and favour convective processes leading to an overall increase of precipitation over urban areas. The diurnal cycle of these effects is reflected in the atmospheric footprint of cities on variables such as humidity and cloud mixing ratio and accompanies changes in precipitation.

  1. Simulated versus observed patterns of warming over the extratropical Northern Hemisphere continents during the cold season

    PubMed Central

    Wallace, John M.; Fu, Qiang; Smoliak, Brian V.; Lin, Pu; Johanson, Celeste M.

    2012-01-01

    A suite of the historical simulations run with the Intergovernmental Panel on Climate Change Fourth Assessment Report (IPCC AR4) models forced by greenhouse gases, aerosols, stratospheric ozone depletion, and volcanic eruptions and a second suite of simulations forced by increasing CO2 concentrations alone are compared with observations for the reference interval 1965–2000. Surface air temperature trends are disaggregated by boreal cold (November-April) versus warm (May-October) seasons and by high latitude northern (N: 40°–90 °N) versus southern (S: 60 °S–40 °N) domains. A dynamical adjustment is applied to remove the component of the cold-season surface air temperature trends (over land areas poleward of 40 °N) that are attributable to changing atmospheric circulation patterns. The model simulations do not simulate the full extent of the wintertime warming over the high-latitude Northern Hemisphere continents during the later 20th century, much of which was dynamically induced. Expressed as fractions of the concurrent trend in global-mean sea surface temperature, the relative magnitude of the dynamically induced wintertime warming over domain N in the observations, the simulations with multiple forcings, and the runs forced by the buildup of greenhouse gases only is 7∶2∶1, and roughly comparable to the relative magnitude of the concurrent sea-level pressure trends. These results support the notion that the enhanced wintertime warming over high northern latitudes from 1965 to 2000 was mainly a reflection of unforced variability of the coupled climate system. Some of the simulations exhibit an enhancement of the warming along the Arctic coast, suggestive of exaggerated feedbacks. PMID:22847408

  2. The continent-ocean transition at the mid-northern margin of the South China Sea

    NASA Astrophysics Data System (ADS)

    Gao, Jinwei; Wu, Shiguo; McIntosh, Kirk; Mi, Lijun; Yao, Bochu; Chen, Zeman; Jia, Liankai

    2015-07-01

    The northern margin of the South China Sea (SCS) has particular structural and stratigraphic characteristics that are somewhat different from those described in typical passive margin models. The differences are attributable to poly-phase tectonic movements and magmatic activity resulting from the interaction among the Eurasian, Philippine Sea and Indo-Australian plates. Based on several crustal-scale multi-channel seismic reflection profiles and satellite gravity data across the northern SCS margin, this paper analyzes the structures, volcanoes and deep crust of the continent-ocean transition zone (COT) at the mid-northern margin of the SCS to study the patterns and model of extension there. The results indicate that the COT is limited landward by basin-bounding faults near Baiyun sag and is bounded by seaward-dipping normal faults near the oceanic basin in our seismic lines. The shallow anatomy of the COT is characterized by rift depression, structural highs with igneous rock and/or a volcanic zone or a zone of tilted fault blocks at the distal edge. Gravity modeling revealed that a high velocity layer (HVL) with a 0.8-6-km thickness is frequently present in the slope below the lower crust. Our study shows that the HVL is only located in the eastern portion of the northern SCS margin based on the available geophysical data. We infer from this that the presence of an HVL is not required in the COT at the northern SCS margin. The magmatic intrusions and HVL may be related to partial melting caused by the decompression of a passive, upwelling asthenosphere, which resulted primarily in post-rifting underplating and magmatic emplacement or modification of the crust. Based on this study, we propose that an intermediate mode of rifting was active in the mid-northern margin of the SCS with characteristics that are closer to those of the magma-poor margins than those of volcanic margins.

  3. Present-day groundwater recharge estimation in parts of the Indian Sub-Continent

    NASA Astrophysics Data System (ADS)

    Bhanja, S. N.; Mukherjee, A.; Wada, Y.; Scanlon, B. R.; Taylor, R. G.; Rodell, M.; Malakar, P.

    2015-12-01

    Large part of global population has been dependent on groundwater as a source of fresh water. The demand would further increase with increasing population and stress associated with climate change. We tried to provide regional-scale groundwater recharge estimates in a large part of Indian Sub-Continent. A combination of ground-based, satellite-based and numerical model simulated recharge estimates were presented in the densely populated region. Three different methods: an intense network of observational wells (n>13,000 wells), a satellite (TRMM) and global land-surface model (CLM) outputs, and a global-scale hydrological model (PCR GLOBWB) were employed to calculate recharge estimates. Groundwater recharge values exhibit large spatial variations over the entire region on the basis of aquifer hydrogeology, precipitation and groundwater withdrawal patterns. Groundwater recharge estimates from all three estimation techniques were found to be higher (>300 mm/year) in fertile planes of Indus-Ganges-Brahmaputra (IGB) river basins. A combination of favorable hydrogeologic conditions (porosity, permeability etc.), comparatively higher rates of precipitation, and return flow from rapidly withdrawn irrigation water might influence occurrence of high recharge rates. However, central and southern study area experiences lower recharge rates (<200 mm/year), might be associated with unfavorable hydrogeologic conditions associated with cratonic provinces. Statistical analysis of inter-comparison between the three different recharge estimates show good matches in some of the areas. Recharge estimates indicate dynamic nature of groundwater recharge as a function of precipitation, land use pattern, and hydrogeologic parameters. On a first hand basis, the estimates will help policy makers to understand groundwater recharge process over the densely populated region and finally would facilitate to implement sustainable policy for securing water security.

  4. Arc-parallel extrusion of the Timor sector of the Banda arc-continent collision

    NASA Astrophysics Data System (ADS)

    Duffy, Brendan; Quigley, Mark; Harris, Ron; Ring, Uwe

    2013-06-01

    studies of synorogenic basins in Timor using field and remote sensing techniques provide new structural and geomorphic evidence for syn-collisional extension in the converging plate boundary zone between the Australian Plate and Banda Arc. Fault mapping and kinematic analysis at scales ranging from outcrop (<1 m2) to the dimensions of the active orogen in East Timor (~100 km2) identify a predominance of NW-SE oriented dextral-normal faults and NE-SW oriented sinistral-normal faults that collectively bound large (5-20 km2) bedrock massifs throughout the island. These fault systems intersect at non-Andersonian conjugate angles of approximately 120° and accommodate an estimated 20 km of NE-directed extension across the Timor orogen based on reconstructions of fault-dismembered massifs. Major orogen-parallel ENE-oriented faults on the northern and southern sides of Timor exhibit normal-sinistral and normal-dextral kinematics, respectively. The overall pattern of deformation is one of lateral crustal extrusion sub-parallel to the Banda Arc. Stratigraphic relationships suggest that extrusion began prior to 5.5 Ma, before pronounced rapid uplift of the orogen. We link this to progressive coupling of the fore-arc to an underthrust plateau on the Australian Plate and subduction of its ocean crust. Our results enable us to track the structural evolution of the upper crust during dramatic plate-boundary reorganizations accompanying the transition from subduction to collision. The deformation structures that we document suggest that both upper and lower plate deformation during incipient island arc-continent collision was largely controlled by the geometry and topography of the lower plate.

  5. Highly variable phenology across the driest inhabited continent characterized by the Australian Phenology Product

    NASA Astrophysics Data System (ADS)

    Broich, M.; Huete, A. R.; Held, A. A.; Ma, X.; Davies, K.; Restrepo-Coupe, N.; Devadas, R.

    2013-12-01

    This work for the first time quantified inter- and intra-annual variabilities in phenological cycles across Australia for 2000-2013 using Moderate Resolution Imaging Spectroradiometer (MODIS) Enhanced Vegetation Index (EVI) data as input for the Australian Phenology Product. The Australian Phenology Product was designed to accommodate the complexity of Australian conditions featuring vast areas covered by arid and semi arid ecosystems. The product was developed under the Australian Terrestrial Ecosystem Research Network (TERN) and is disseminated by the AusCover TERN Sydney node. It provides an internally consistent quantification of phenological cycles of vegetation greening and browning that can inform, agricultural applications, wildfire fuel accumulation, land surface modeling, ecosystem research and climate change studies. Based on the Australian Phenology Product we were able to characterize high inter- and intra-annual variabilites of phenological cycles across large areas of arid and semi-arid Australia between 2000 and 2013 and linked these spatial-temporal variability patterns with atmospheric circulation indices such as SOI. This resulted in a spatially explicit representation of extreme vegetation productivity response to regional climatic variability highlighting the effect of the transition between El Nino drought to La Nina floods in 2011 (Fig 1: average and standard anomalies of annual EVI integrated over the phenological cycle [iEVI]). This first characterization of the inter-annual variability in vegetation phenology across the driest inhabited continent is of special interest to vegetation and ecosystem monitoring and modeling as Australia's rainfall has been described as more variable and the vegetation as different from equivalent climatic zone around the world.

  6. Variations in heat flow across the ocean—continent transition in the Iberia abyssal plain

    NASA Astrophysics Data System (ADS)

    Louden, Keith E.; Sibuet, Jean-Claude; Harmegnies, Francois

    1997-10-01

    New heat flow observations have been made in the Iberia abyssal plain off the Galicia margin along the transect of Ocean Drilling Program Leg 149 drill sites, in order to investigate the nature of this unusually wide and deep continent-ocean transition region. Our results indicate the presence of three separate zones. Average values of 47.5 ± 3 mW m -2 in the westernmost zone III agree with predictions of standard oceanic lithospheric models for its estimated age of 126 Ma. In contrast, the heat flow within zone II is 5-15 mW m -2 higher than predicted, assuming that the mantle heat flow remains constant across the basin. This region of high values is coincident with the location of a major intra-crustal "S"-type reflector east of ODP Site 900, and the anomaly is consistent with the presence of 2-3 km of primarily upper continental crust above the reflector, with concentrations of radiogenic components similar to those from granodiorite samples dredged off Galicia Bank. It is not, however, consistent with the low values of heat production measured on gabbroic samples from its western end at ODP Site 900. In zone I, detailed measurements across the tilted fault block south of ODP Site 901 show consistent variations which closely match predictions due to the effects of basement structure and sediment deposition. There is no evidence for variations due to vertical convective transport along the dipping basement fault block. Once corrected for these variations, measurements in zone 1 yield average values that agree quite well with previous measurements across Galicia Bank, indicating no systematic landward increase in heat flow with decreasing amounts of continental extension.

  7. INDUCED SEISMICITY. High-rate injection is associated with the increase in U.S. mid-continent seismicity.

    PubMed

    Weingarten, M; Ge, S; Godt, J W; Bekins, B A; Rubinstein, J L

    2015-06-19

    An unprecedented increase in earthquakes in the U.S. mid-continent began in 2009. Many of these earthquakes have been documented as induced by wastewater injection. We examine the relationship between wastewater injection and U.S. mid-continent seismicity using a newly assembled injection well database for the central and eastern United States. We find that the entire increase in earthquake rate is associated with fluid injection wells. High-rate injection wells (>300,000 barrels per month) are much more likely to be associated with earthquakes than lower-rate wells. At the scale of our study, a well's cumulative injected volume, monthly wellhead pressure, depth, and proximity to crystalline basement do not strongly correlate with earthquake association. Managing injection rates may be a useful tool to minimize the likelihood of induced earthquakes. PMID:26089509

  8. High-rate injection is associated with the increase in U.S. mid-continent seismicity

    NASA Astrophysics Data System (ADS)

    Weingarten, M.; Ge, S.; Godt, J. W.; Bekins, B. A.; Rubinstein, J. L.

    2015-06-01

    An unprecedented increase in earthquakes in the U.S. mid-continent began in 2009. Many of these earthquakes have been documented as induced by wastewater injection. We examine the relationship between wastewater injection and U.S. mid-continent seismicity using a newly assembled injection well database for the central and eastern United States. We find that the entire increase in earthquake rate is associated with fluid injection wells. High-rate injection wells (>300,000 barrels per month) are much more likely to be associated with earthquakes than lower-rate wells. At the scale of our study, a well’s cumulative injected volume, monthly wellhead pressure, depth, and proximity to crystalline basement do not strongly correlate with earthquake association. Managing injection rates may be a useful tool to minimize the likelihood of induced earthquakes.

  9. High-rate injection is associated with the increase in U.S. mid-continent seismicity

    USGS Publications Warehouse

    Weingarten, Matthew; Ge, Shemin; Godt, Jonathan W.; Bekins, Barbara A.; Rubinstein, Justin L.

    2015-01-01

    An unprecedented increase in earthquakes in the U.S. mid-continent began in 2009. Many of these earthquakes have been documented as induced by wastewater injection. We examine the relationship between wastewater injection and U.S. mid-continent seismicity using a newly assembled injection well database for the central and eastern United States. We find that the entire increase in earthquake rate is associated with fluid injection wells. High-rate injection wells (>300,000 barrels per month) are much more likely to be associated with earthquakes than lower-rate wells. At the scale of our study, a well’s cumulative injected volume, monthly wellhead pressure, depth, and proximity to crystalline basement do not strongly correlate with earthquake association. Managing injection rates may be a useful tool to minimize the likelihood of induced earthquakes.

  10. Crustal Structure and Lithospheric Rupture Process of the Continent-Ocean Boundary of the South China Sea

    NASA Astrophysics Data System (ADS)

    Song, T. R.; Li, C. F.; Shi, H.; Ding, W.; Li, J.

    2014-12-01

    Seismic reflection profiles acquired in the continent-ocean transition zone (COT) of South China Sea provide a detailed view of Moho and deep crustal reflectors and continental lithosphere extension and breakup styles. At the north margin, rift basins are often bounded by listric normal faults, most of which are terminated at the base of the upper crust. The upper-lower crust interface corresponds to the brittle-ductile transition zone, where listric faults tend to converge into a low angle detachment fault. According to calculated stretch factors in different depth scales (upper crust, lower crust) along several profiles, hyper-extended continental crust is widespread, with the upper crust being often preferentially more thinned than the lower crust. The ductile lower crust is more resistant to faulting and therefore stretching. A high-velocity lower crustal layer represents either magmatic underplating or pervasive lower crustal intrusions in the northern margin. The possible lower crust ductile flow and the high-velocity lower crustal layer may have contributed to extension discrepancy, leading to direct exposure of lower crust material landward of the continent-ocean boundary. Hyper-extended continental crust and thick syn-rift sequence developed during a long period of rifting prior to the inception of seafloor spreading are also observed in the southern continental margin, further suggesting depth-dependent continental extension in the South China Sea. Basement highs and discontinuity in Moho reflector are common features around the continent-ocean boundary of South China Sea. The basement ridges are located at the landward edge of the continent-ocean boundary and possibly composed by lower crust material. The COT is ~50 km wide, where the gravity anomaly is approximately zero and the Moho reflector is discontinuous. The COT here is narrower than those found in other magma-poor margins (e.g., Iberia-Newfoundland type), indicating that normal oceanic crust

  11. The potential impacts of warmer-continent-related lower-layer equatorial westerly wind on tropical cyclone initiation

    NASA Astrophysics Data System (ADS)

    Yuan, Zhuojian; Qian, Yu-Kun; Qi, Jindian; Wu, Junjie

    2012-03-01

    Global climate models predict that the increasing Amazonian-deforestation rates cause rising temperatures (increases of 1.8°C to 8°C under different conditions) and Amazonian drying over the 21st century. Observations in the 20th century also show that over the warmer continent and the nearby western South Atlantic Ocean, the lower-layer equatorial westerly wind (LLEWW) strengthens with the initiation of tropical cyclones (TCs). The warmer-continent-related LLEWW can result from the Coriolis-force-induced deflection of the cross-equatorial flow (similar to the well-known heat-island effect on sea breeze) driven by the enhanced land-sea contrast between the warmer urbanized continents and relatively cold oceans. This study focuses on the processes relating the warmer-continent-related LLEWW to the TC initiation and demonstrates that the LLEWW embedded in trade easterlies can directly initiate TCs by creating cyclonic wind shears and forming the intertropical convergence zone. In addition to this direct effect, the LLEWW combined with the rotating Earth can boost additional updraft vapor over the high sea-surface temperature region (factor 1), facilitating a surface-to-midtroposphere moist layer (factor 2) and convective instability (factor 3) followed by diabatic processes. According to previous studies, the diabatic heating in a finite equatorial region also activates TCs (factor 4) on each side of the Equator with weak vertical shear (factor 5). Factors 1-5 are favorable conditions for the initiation of severe TCs. Statistical analyses show that the earliest signal of sustained LLEWW not only leads the earliest signal of sustained tropical depression by >3 days but also explains a higher percentage of total variance.

  12. The history of the North African mitochondrial DNA haplogroup U6 gene flow into the African, Eurasian and American continents

    PubMed Central

    2014-01-01

    Background Complete mitochondrial DNA (mtDNA) genome analyses have greatly improved the phylogeny and phylogeography of human mtDNA. Human mitochondrial DNA haplogroup U6 has been considered as a molecular signal of a Paleolithic return to North Africa of modern humans from southwestern Asia. Results Using 230 complete sequences we have refined the U6 phylogeny, and improved the phylogeographic information by the analysis of 761 partial sequences. This approach provides chronological limits for its arrival to Africa, followed by its spreads there according to climatic fluctuations, and its secondary prehistoric and historic migrations out of Africa colonizing Europe, the Canary Islands and the American Continent. Conclusions The U6 expansions and contractions inside Africa faithfully reflect the climatic fluctuations that occurred in this Continent affecting also the Canary Islands. Mediterranean contacts drove these lineages to Europe, at least since the Neolithic. In turn, the European colonization brought different U6 lineages throughout the American Continent leaving the specific sign of the colonizers origin. PMID:24885141

  13. Pattern and process in Northern Rocky Mountain headwaters: Ecological linkages in the headwaters of the Crown of the Continent

    SciTech Connect

    Hauer, F.R.; Stanford, J.A.; Lorang, M.S.

    2007-02-15

    The Crown of the Continent is one of the premiere ecosystems in North America containing Waterton-Glacier International Peace Park, the Bob Marshall-Great Bear-Scapegoat Wilderness Complex in Montana, various Provincial Parks in British Columbia and Alberta, several national and state forest lands in the USA, and Crown Lands in Canada. The region is also the headwater source for three of the continent's great rivers: Columbia, Missouri and Saskatchewan that flow to the Pacific, Atlantic and Arctic Oceans, respectively. While the region has many remarkably pristine headwater streams and receiving rivers, there are many pending threats to water quality and quantity. One of the most urgent threats comes from the coal and gas fields in the northern part of the Crown of the Continent, where coal deposits are proposed for mountain-top removal and open-pit mining operations. This will have significant effects on the waters of the region, its native plants and animals and quality of life of the people.

  14. Deep crustal structure and continent-ocean boundary along the Galicia continental margin (NW Iberia)

    NASA Astrophysics Data System (ADS)

    Druet, María; Muñoz-Martín, Alfonso; Carbó, Andrés; Acosta, Juan; Granja Bruña, José Luis; Llanes, Pilar; Vázquez, Juan-Tomás; Ercilla, Gemma

    2016-04-01

    The Galicia continental margin is a magma-poor rifted margin with an extremely complex structure. Its formation involves several rifting episodes during the Mesozoic in the vicinity of a ridge triple junction, which produces a change in the orientation of the main structures. In addition, there is an overimposed Cenozoic partial tectonic inversion along its northern border. Although this continental margin has been widely studied since the 70's, most studies have focused on its western part in the transition to the Iberia Abyssal Plain, and there is a significant lack of information on the north and northwestern flanks of this margin. This fact, along with its great structural complexity, has resulted in the absence of a previous comprehensive regional geodynamic model integrating all the processes observed. In the present study we integrate a large volume of new geophysical data (gravity, swath bathymetry and 2D multichannel reflection seismic). Data come from the systematic mapping of the Spanish EEZ project which provides a dense grid of gravity data and full seafloor coverage with swath bathymetry, and from the ERGAP project which provides serially-arranged 2D seismic reflection profiles across the NW Iberia margin. The combined interpretation and modelling of this new information has arisen significant constraints on the origin, the deep crustal structure and the physiographic complexity of the margin, as well as on the characterization of the along- and across-strike variation of the ocean-continent transition along NW Iberia margin. The analysis of this information leads us to propose a conceptual model for the initiation of the tectonic inversion of a magma-poor rifted margin. Finally, a framework for the geodynamic evolution of the Galicia margin has been constructed, involving three main stages: A) an early stage from the end of rifting and oceanic drift in the Bay of Biscay (Santonian); B) an intermediate stage with the beginning of tectonic inversion in

  15. Genetic Structure of Natural Populations of Escherichia coli in Wild Hosts on Different Continents

    PubMed Central

    Souza, Valeria; Rocha, Martha; Valera, Aldo; Eguiarte, Luis E.

    1999-01-01

    Current knowledge of genotypic and phenotypic diversity in the species Escherichia coli is based almost entirely on strains recovered from humans or zoo animals. In this study, we analyzed a collection of 202 strains obtained from 81 mammalian species representing 39 families and 14 orders in Australia and the Americas, as well as several reference strains; we also included a strain from a reptile and 10 from different families of birds collected in Mexico. The strains were characterized genotypically by multilocus enzyme electrophoresis (MLEE) and phenotypically by patterns of sugar utilization, antibiotic resistance, and plasmid profile. MLEE analysis yielded an estimated genetic diversity (H) of 0.682 for 11 loci. The observed genetic diversity in this sample is the greatest yet reported for E. coli. However, this genetic diversity is not randomly distributed; geographic effects and host taxonomic group accounted for most of the genetic differentiation. The genetic relationship among the strains showed that they are more associated by origin and host order than is expected by chance. In a dendrogram, the ancestral cluster includes primarily strains from Australia and ECOR strains from groups B and C. The most differentiated E. coli in our analysis are strains from Mexican carnivores and strains from humans, including those in the ECOR group A. The kinds and numbers of sugars utilized by the strains varied by host taxonomic group and country of origin. Strains isolated from bats were found to exploit the greatest range of sugars, while those from primates utilized the fewest. Toxins are more frequent in strains from rodents from both continents than in any other taxonomic group. Strains from Mexican wild mammals were, on average, as resistant to antibiotics as strains from humans in cities. On average, the Australian strains presented a lower antibiotic resistance than the Mexican strains. However, strains recovered from hosts in cities carried significantly more

  16. Failure was not an option- the Mid-Continent Rift system succeeded

    NASA Astrophysics Data System (ADS)

    Merino, M.; Stein, C. A.; Stein, S. A.; Keller, G. R.; Flesch, L. M.; Jurdy, D. M.

    2013-12-01

    The 1.1 Ga Mid-Continent Rift (MCR) in North America is often viewed as a failed rift formed by isolated midplate volcanism and extension within the ~1.3-~0.98 Ga Grenville orogeny. An alternative view is suggested by analogy with younger and morphologically similar rift systems, whose plate tectonic settings are more easily understood because their surroundings - including seafloor with magnetic anomalies - have not been deformed or destroyed by subsequent collisions and rifting events. In this view, the MCR was part of a larger plate boundary rifting event that resulted in a successful episode of seafloor spreading. This view is motivated by various pieces of evidence. The MCR rifting looks much like rigid plate block motion, such as associated with the West Central African Rift systems formed during the Mesozoic breakup of Africa and South America and the ongoing rifting in the East African Rift region with seafloor spreading in the Gulf of Aden and the Red Sea. This view explains the affinities of the Grenville-age rocks in the central and southern Appalachians to Amazonia rather than Canadian Grenville-age Appalachian rocks. The MCR extends farther to the south than traditionally assumed along the East Continental Gravity High (a buried feature from Ohio to Alabama). This failed portion of the rift system connected to the rift successfully separating Laurentia and Amazonia. The seafloor spreading separating Amazonia from Laurentia may explain the former's relative motion toward Greenland and Baltica. This model is consistent with some of the ~1.1 Ga geological events in Amazonia. A change in the apparent polar wander path for Laurentia during the period of volcanism of the MCR could be attributed to this plate reconfiguration. The extensional phase on the MCR may have ended because motion was taken up by seafloor spreading between Laurentia and Amazonia rather ending due to another continental collision. Later reverse faulting on the MCR normal faults due to

  17. Revisiting Seafloor-Spreading in the Red Sea: Basement Nature, Transforms and Ocean-Continent Boundary

    NASA Astrophysics Data System (ADS)

    Tapponnier, P.; Dyment, J.; Zinger, M. A.; Franken, D.; Afifi, A. M.; Wyllie, A.; Ali, H. G.; Hanbal, I.

    2013-12-01

    A new marine geophysical survey on the Saudi Arabian side of the Red Sea confirms early inferences that ~ 2/3 of the eastern Red Sea is floored by oceanic crust. Most seismic profiles south of 24°N show a strongly reflective, landward-deepening volcanic basement up to ~ 100 km east of the axial ridge, beneath thick evaporitic deposits. This position of the Ocean-Continent Boundary (OCB) is consistent with gravity measurements. The low amplitudes and long wavelengths of magnetic anomalies older than Chrons 1-3 can be accounted for by low-pass filtering due to thick sediments. Seafloor-spreading throughout the Red Sea started around 15 Ma, as in the western Gulf of Aden. Its onset was coeval with the activation of the Aqaba/Levant transform and short-cutting of the Gulf of Suez. The main difference between the southern and northern Red Sea lies not in the nature of the crust but in the direction and modulus of the plate motion rate. The ~ 30° counterclockwise strike change and halving of the spreading rate (~ 16 to ~ 8 mm/yr) between the Hermil (17°N) and Suez triple junctions results in a shift from slow (≈ North Atlantic) to highly oblique, ultra-slow (≈ Southwest Indian) ridge type. The obliquity of spreading in the central and northern basins is taken up by transform discontinuities that stop ~ 40 km short of the coastline, at the OCB. Three large transform fault systems (Jeddah, Zabargad, El Akhawein) nucleated as continental transfer faults reactivating NNE-trending Proterozoic shear zones. The former two systems divide the Red Sea into three main basins. Between ~15 and ~5 Ma, for about 10 million years, thick evaporites were deposited directly on top of oceanic crust in deep water, as the depositional environment, modulated by climate, became restricted by the Suez and Afar/Bab-el-Mandeb volcano-tectonic 'flood-gates.' The presence of these thick deposits (up to ~ 8 km) suffices to account for the difference between the Red Sea and the Gulf of Aden

  18. Anomalous Subsidence at the Ocean Continent Transition of the Gulf of Aden Rifted Continental Margin

    NASA Astrophysics Data System (ADS)

    Cowie, Leanne; Kusznir, Nick; Leroy, Sylvie

    2013-04-01

    It has been proposed that some rifted continental margins have anomalous subsidence and that at break-up they were elevated at shallower bathymetries than the isostatic response predicted by classical rift models (McKenzie, 1978). The existence of anomalous syn- or early-post break-up subsidence of this form would have important implications for our understanding of the geodynamics of continental break-up and sea-floor spreading initiation. We have investigated subsidence of the young rifted continental margin of the eastern Gulf of Aden, focussing on the western Oman margin (break-up age 17.6 Ma). Lucazeau et al. (2008) have found that the observed bathymetry here is approximately 1 km shallower than the predicted bathymetry. In order to examine the proposition of an anomalous early post break-up subsidence history of the Omani Gulf of Aden rifted continental margin, we have determined the subsidence of the oldest oceanic crust adjacent to the continent-ocean boundary (COB) using residual depth anomaly (RDA) analysis corrected for sediment loading and oceanic crustal thickness variation. RDAs corrected for sediment loading using flexural backstripping and decompaction have been calculated by comparing observed and age predicted oceanic bathymetries in order to identify anomalous subsidence of the Gulf of Aden rifted continental margin. Age predicted bathymetric anomalies have been calculated using the thermal plate model predictions of Crosby and McKenzie (2009). Non-zero RDAs at the Omani Gulf of Aden rifted continental margin can be the result of non standard oceanic crustal thickness or the effect of mantle dynamic topography or a non-classical rift and break-up model. Oceanic crustal basement thicknesses from gravity inversion together with Airy isostasy have been used to predict a "synthetic" gravity RDA, in order to determine the RDA contribution from non-standard oceanic crustal thickness. Gravity inversion, used to determine crustal basement thickness

  19. NorthAm Fest : fostering a North American continent approach to countering terrorism.

    SciTech Connect

    Gerdes, Dick; Moore, Judy Hennessey; Whitley, John B.; Turnley, Jessica Glicken; Oborotova, Marina

    2004-12-01

    On September 14-16, 2004, the Advanced Concepts Group of Sandia National Laboratories in conjunction with the University of Texas at El Paso and the North American Institute hosted a workshop (fest) designed to explore the concept of a North American continental approach to countering terrorism. The fest began with the basic premise that the successful defense of North America against the threat of terrorism will require close collaboration among the North American allies--Canada, Mexico and the U.S.--as well as a powerful set of information collection and analysis tools and deterrence strategies. The NorthAm Fest recast the notion of ''homeland defense'' as a tri-national effort to protect the North American continent against an evolving threat that respects no borders. This is a report of the event summarizing the ideas explored. The fest examined the uniqueness of dealing with terrorism from a tri-national North American viewpoint, the role and possible features of joint security systems, concepts for ideal continental security systems for North America, and the challenges and opportunities for such systems to become reality. The following issues were identified as most important for the advancement of this concept. (1) The three countries share a set of core values--democracy, prosperity and security--which form the basis for joint interactions and allow for the development of a culture of cooperation without affecting the sovereignty of the members. (2) The creation of a continental defensive strategy will require a set of strategic guidelines and that smart secure borders play a pivotal role. (3) Joint security systems will need to operate from a set of complementary but not identical policies and procedures. (4) There is a value in joint task forces for response and shared information systems for the prevention of attacks. (5) The private sector must play a critical role in cross-border interactions. Finally, participants envisioned a ''Tri-National Security

  20. Physical Climatology of Indonesian Maritime Continent: An Overview of Observational Studies

    NASA Astrophysics Data System (ADS)

    Yamanaka, M. D.

    2014-12-01

    The Indonesian maritime continent (IMC) is a miniature of our land-sea coexisting planet Earth. Firstly, without interior activity, the Earth becomes an even-surfaced "aqua-planet" with both atmosphere and ocean flowing almost zonally, and solar differential heating generates (global thermal tides and) Hadley's meridional circulations with ITCZ along the equator as observed actually over open (Indian and Pacific) oceans in the both sides of IMC. ITCZ involves intraseasonal variations or super cloud clusters moving eastward. Secondly, the lands and seas over the actual Earth have been keeping the area ratio of 3:7 (similar to that of islands and inland/surrounding seas in IMC), but their displacements have produced IMC near the equator, which turns equatorial Pacific easterly current northward (Kuroshio) and reflects equatorial oceanic waves inducing coupled ocean-atmosphere interannual variations such as ENSO and IOD, or displacements of Walker's zonal circulations. Thirdly, because IMC consists of many large/small islands with very long coastlines, many narrow straits become a dam for the global (Pacific to Indian) ocean circulation, and the land-sea heat capacity contrasts along the coastlines generate the world's largest rainfall with diurnal cycles (sea-land breeze circulations). The diurnal cycles are dominant in the rainy season (austral summer in Jawa and Bali), because rainfall-induced sprinkler-like land cooling reverses the trans-coastal temperature gradient before sunrise, and subsequent clear sky on land until around noon provides solar heating dependent on season. These processes lead to rapid land/hydrosphere-atmosphere water exchange, local air pollutant washout, and transequatorial boreal winter monsoon (cold surge). In El Niño years the cooler sea-surface temperature suppresses the morning coastal-sea rainfall, and induces often serious smog over IMC. Lastly, high-resolution observations/models covering both over islands and seas are necessary. A

  1. A review of droughts in the African continent: a geospatial and long-term perspective

    NASA Astrophysics Data System (ADS)

    Masih, I.; Maskey, S.; Mussá, F. E. F.; Trambauer, P.

    2014-03-01

    This paper presents a comprehensive review and analysis of the available literature and information on droughts to build a continental, regional and country level perspective on geospatial and temporal variation of droughts in Africa. The study is based on the review and analysis of droughts occurred during 1900-2013 as well as evidence available from past centuries based on studies on the lake sediment analysis, tree-ring chronologies and written and oral histories and future predictions from the global climate change models. Most of the studies based on instrumental records indicate that droughts have become more frequent, intense and widespread during the last 50 yr. The extreme droughts of 1972-1973, 1983-1984 and 1991-1992 were continental in nature and stand unique in the available records. Additionally, many severe and prolonged droughts were recorded in the recent past such as the 1999-2002 drought in Northwest Africa, 1970s and 1980s droughts in West Africa (Sahel), 2010-2011 drought in East Africa (Horn of Africa) and 2001-2003 drought in Southern and Southeast Africa, to name a few. The available (though limited) evidence before the 20th century confirms the occurrence of several extreme and multi-year droughts during each century, with the most prolonged and intense droughts that occurred in Sahel and Equatorial East Africa regions. Complex and highly variant nature of many physical mechanisms such as El Niño-Southern Oscillation (ENSO), Sea Surface Temperature (SST) and land-atmosphere feedback adds to the daunting challenge of drought monitoring and forecasting. The future predictions of droughts based on global climate models indicate increased droughts and aridity at the continental scale but large differences exist due to model limitations and complexity of the processes especially for Sahel and North Africa regions. However, the available evidence from the past clearly shows that the African continent is likely to face extreme and widespread

  2. A review of droughts on the African continent: a geospatial and long-term perspective

    NASA Astrophysics Data System (ADS)

    Masih, I.; Maskey, S.; Mussá, F. E. F.; Trambauer, P.

    2014-09-01

    This paper presents a comprehensive review and analysis of the available literature and information on droughts to build a continental, regional and country level perspective on geospatial and temporal variation of droughts in Africa. The study is based on the review and analysis of droughts occurred during 1900-2013, as well as evidence available from past centuries based on studies on the lake sediment analysis, tree-ring chronologies and written and oral histories and future predictions from the global climate change models. Most of the studies based on instrumental records indicate that droughts have become more frequent, intense and widespread during the last 50 years. The extreme droughts of 1972-1973, 1983-1984 and 1991-1992 were continental in nature and stand unique in the available records. Additionally, many severe and prolonged droughts were recorded in the recent past such as the 1999-2002 drought in northwest Africa, 1970s and 1980s droughts in western Africa (Sahel), 2010-2011 drought in eastern Africa (Horn of Africa) and 2001-2003 drought in southern and southeastern Africa, to name a few. The available (though limited) evidence before the 20th century confirms the occurrence of several extreme and multi-year droughts during each century, with the most prolonged and intense droughts that occurred in Sahel and equatorial eastern Africa. The complex and highly variant nature of many physical mechanisms such as El Niño-Southern Oscillation (ENSO), sea surface temperature (SST) and land-atmosphere feedback adds to the daunting challenge of drought monitoring and forecasting. The future predictions of droughts based on global climate models indicate increased droughts and aridity at the continental scale but large differences exist due to model limitations and complexity of the processes especially for Sahel and northern Africa. However, the available evidence from the past clearly shows that the African continent is likely to face extreme and

  3. Arctic Crustal Thickness and Ocean-Continent Transition from Gravity Inversion Incorporating a Lithosphere Thermal Correction

    NASA Astrophysics Data System (ADS)

    Greenhalgh, E.; Kusznir, N. J.; Lebedeva-Ivanova, N.; Alvey, A.; Gaina, C.; Torsvik, T. H.

    2007-12-01

    Crustal thickness and continental lithosphere thinning factors have been determined for the High Arctic using a gravity inversion method which incorporates a lithosphere thermal gravity anomaly correction. Continental lithosphere thinning factor maps, determined by the inversion of the NGA (U) Arctic Gravity Project data have been used to predict the distribution of oceanic lithosphere and ocean-continent transition (OCT) location for the Amerasia Basin. Thin crust and high lithosphere thinning factors are predicted in the Makarov, Podvodnikov and Canada Basins consistent with these basins being oceanic. Larger crustal thicknesses, in the range 20 - 30 km, are predicted for the Lomonosov, Alpha and Mendeleev Ridges. Moho depths predicted by gravity inversion have been compared with seismic estimates for the TransArctica and Arctica profiles with seismically observed sediment thickness included in the gravity inversion. Agreement between gravity and seismic Moho depths is generally good. The largest differences between gravity and seismic Moho depths occur where lower crustal seismic velocities, Vp, are in excess of ~ 7.3km/s. Gravity inversion to determine Moho depth and crustal thickness variation is carried out in the 3D spectral domain. A correction for the large negative residual thermal gravity anomaly within oceanic and stretched continental margin lithosphere is made and requires a lithosphere thermal model to predict the present day lithosphere thermal anomaly. For continental margin lithosphere, the lithosphere thermal perturbation is calculated from the lithosphere thinning factor (1-1/beta) obtained from crustal thinning determined by gravity inversion and breakup age for thermal re-equilibration time. A correction is made for crustal volcanic addition due to decompression melting during breakup and sea-floor spreading. For the Amerasia Basin, where ocean isochrons are uncertain, all lithosphere is assumed to be initially continental, and a lithosphere

  4. Thermal models of dyke intrusion during development of continent-ocean transition

    NASA Astrophysics Data System (ADS)

    Daniels, K. A.; Bastow, I. D.; Keir, D.; Sparks, R. S. J.; Menand, T.

    2014-01-01

    thickness and Moho depth in the Danakil region of northernmost Afar are markedly reduced and seismicity is shallower than in the MER. Thermally driven variations in crustal rheology over time in response to dyke intrusion thus play an important role in the development of continent-ocean transition.

  5. The continent-ocean transition on the northwestern South China Sea

    NASA Astrophysics Data System (ADS)

    Cameselle, Alejandra L.; Ranero, César R.; Franke, Dieter; Barckhausen, Udo

    2015-04-01

    Rifted margins are created as a result of stretching and breakup of continental lithosphere that eventually leads to oceanic spreading and formation of a new oceanic basin. A cornerstone for understanding how rift characteristics vary along strike in the same system and what processes control the final transition to seafloor spreading is the continent-ocean transition (COT). We use four regional multichannel seismic profiles and published magnetic lineations to study the structure and variability of COT on the northwest subbasin (NWSB) of the South China Sea and to discern continental from oceanic domains. The continental domain is characterized by tilted fault blocks overlaid by thick syn-rift sedimentary units and fairly continuous Moho reflections typically at 8-10 s twtt. Thickness of the continental crust changes from ~20-25 km under the uppermost slope to ~9-6 km under the lower slope. The oceanic domain is interpreted where a highly reflective top of basement, little faulting, no syntectonic strata, and fairly constant thickness basement (4-8 km) occur. The COT is imaged as a ~5-10 km wide zone where oceanic-type features abut continental-type structures. The South China margin is deformed by abundant normal faults dissecting the continental crust, whereas the conjugate Macclesfield Bank margin displays comparatively abrupt thinning and little faulting. Seismic profiles show an along-strike variation in the tectonic structure of the continental margin. The NE-most lines display ~20-40 km wide segments of intense faulting under the slope and associated continental-crust thinning. Towards the SW, faulting and thinning of the continental crust occurs across a ~100-110 km wide segment. We interpret this 3D structural variability and the narrow COT as a consequence of the abrupt termination of continental rifting tectonics by the NE to SW propagation of a spreading center. We suggest that breakup occurred by spreading center propagation to a larger degree than by

  6. SELECTION AND TREATMENT OF STRIPPER GAS WELLS FOR PRODUCTION ENHANCEMENT IN THE MID-CONTINENT

    SciTech Connect

    Scott Reeves

    2003-03-01

    Stripper gas wells are an important source of domestic energy supply and under constant threat of permanent loss (shut-in) due to marginal economics. In 1998, 192 thousand stripper gas wells produced over a Tcf of gas, at an average rate of less than 16 Mcfd. This represents about 57% of all producing gas wells in the onshore lower-48 states, yet only 8% of production. Reserves of stripper gas wells are estimated to be only 1.6 Tcf, or slightly over 1% of the onshore lower-48 total (end of year 1996 data). Obviously, stripper gas wells are at the very margin of economic sustenance. As the demand for natural gas in the U.S. grows to the forecasted estimate of over 30 Tcf annually by the year 2010, supply from current conventional sources is expected to decline. Therefore, an important need exists to fully exploit known domestic resources of natural gas, including those represented by stripper gas wells. The overall objectives of this project are to develop an efficient and low-cost methodology to broadly categorize the well performance characteristics for a stripper gas field, identify the high-potential candidate wells for remediation, and diagnose the specific causes for well underperformance. With this capability, stripper gas well operators can more efficiently and economically produce these resources and maximize these gas reserves. A further objective is to identify/develop, evaluate and test ''new and novel,'' economically viable remediation options. Finally, it is the objective of this project that all the methods and technologies developed in this project, while being tested in the Mid-Continent, be widely applicable to stripper gas wells of all types across the country. The project activities during the reporting period were: (1) The search for another field site was abandoned after discussion with DOE. There is a clear absence of willing industry partners to participate in this project. The greatest obstacle is having the necessary data to perform the

  7. SELECTION AND TREATMENT OF STRIPPER GAS WELLS FOR PRODUCTION ENHANCEMENT IN THE MID-CONTINENT

    SciTech Connect

    Scott Reeves

    2003-08-01

    Stripper gas wells are an important source of domestic energy supply and under constant threat of permanent loss (shut-in) due to marginal economics. In 1998, 192 thousand stripper gas wells produced over a Tcf of gas, at an average rate of less than 16 Mcfd. This represents about 57% of all producing gas wells in the onshore lower-48 states, yet only 8% of production. Reserves of stripper gas wells are estimated to be only 1.6 Tcf, or slightly over 1% of the onshore lower-48 total (end of year 1996 data). Obviously, stripper gas wells are at the very margin of economic sustenance. As the demand for natural gas in the U.S. grows to the forecasted estimate of over 30 Tcf annually by the year 2010, supply from current conventional sources is expected to decline. Therefore, an important need exists to fully exploit known domestic resources of natural gas, including those represented by stripper gas wells. The overall objectives of this project are to develop an efficient and low-cost methodology to broadly categorize the well performance characteristics for a stripper gas field, identify the high-potential candidate wells for remediation, and diagnose the specific causes for well underperformance. With this capability, stripper gas well operators can more efficiently and economically produce these resources and maximize these gas reserves. A further objective is to identify/develop, evaluate and test ''new and novel,'' economically viable remediation options. Finally, it is the objective of this project that all the methods and technologies developed in this project, while being tested in the Mid-Continent, be widely applicable to stripper gas wells of all types across the country. The project activities during the reporting period were: (1) Compiled information and results of field activities that Oneok has conducted in relation to the project. Field activities have included performing six pressure transient tests, and implementing six workovers, four of which were

  8. SELECTION AND TREATMENT OF STRIPPER GAS WELLS FOR PRODUCTION ENHANCEMENT IN THE MID-CONTINENT

    SciTech Connect

    Scott Reeves

    2003-03-01

    Stripper gas wells are an important source of domestic energy supply and under constant threat of permanent loss (shut-in) due to marginal economics. In 1998, 192 thousand stripper gas wells produced over a Tcf of gas, at an average rate of less than 16 Mcfd. This represents about 57% of all producing gas wells in the onshore lower-48 states, yet only 8% of production. Reserves of stripper gas wells are estimated to be only 1.6 Tcf, or slightly over 1% of the onshore lower-48 total (end of year 1996 data). Obviously, stripper gas wells are at the very margin of economic sustenance. As the demand for natural gas in the U.S. grows to the forecasted estimate of over 30 Tcf annually by the year 2010, supply from current conventional sources is expected to decline. Therefore, an important need exists to fully exploit known domestic resources of natural gas, including those represented by stripper gas wells. The overall objectives of this project are to develop an efficient and low-cost methodology to broadly categorize the well performance characteristics for a stripper gas field, identify the high-potential candidate wells for remediation, and diagnose the specific causes for well underperformance. With this capability, stripper gas well operators can more efficiently and economically produce these resources and maximize these gas reserves. A further objective is to identify/develop, evaluate and test ''new and novel,'' economically viable remediation options. Finally, it is the objective of this project that all the methods and technologies developed in this project, while being tested in the Mid-Continent, be widely applicable to stripper gas wells of all types across the country. The project activities during the reporting period were: (1) Finished preparing the final project report, less the field implementation component. Sent to DOE for review. (2) Continued coordinating the final selection of candidates and field implementation with Oneok. Oneok postponed field

  9. SELECTION AND TREATMENT OF STRIPPER GAS WELLS FOR PRODUCTION ENHANCEMENT IN THE MID-CONTINENT

    SciTech Connect

    Scott Reeves

    2003-03-01

    Stripper gas wells are an important source of domestic energy supply and under constant threat of permanent loss (shut-in) due to marginal economics. In 1998, 192 thousand stripper gas wells produced over a Tcf of gas, at an average rate of less than 16 Mcfd. This represents about 57% of all producing gas wells in the onshore lower-48 states, yet only 8% of production. Reserves of stripper gas wells are estimated to be only 1.6 Tcf, or slightly over 1% of the onshore lower-48 total (end of year 1996 data). Obviously, stripper gas wells are at the very margin of economic sustenance. As the demand for natural gas in the U.S. grows to the forecasted estimate of over 30 Tcf annually by the year 2010, supply from current conventional sources is expected to decline. Therefore, an important need exists to fully exploit known domestic resources of natural gas, including those represented by stripper gas wells. The overall objectives of this project are to develop an efficient and low-cost methodology to broadly categorize the well performance characteristics for a stripper gas field, identify the high-potential candidate wells for remediation, and diagnose the specific causes for well underperformance. With this capability, stripper gas well operators can more efficiently and economically produce these resources and maximize these gas reserves. A further objective is to identify/develop, evaluate and test ''new and novel,'' economically viable remediation options. Finally, it is the objective of this project that all the methods and technologies developed in this project, while being tested in the Mid-Continent, be widely applicable to stripper gas wells of all types across the country. The project activities during the reporting period were: (1) Type curve matching continued during the reporting period. (2) A second data collection trip to Tulsa was performed to gather information on the additional reservoirs to be included in the analysis. Created updated database

  10. SELECTION AND TREATMENT OF STRIPPER GAS WELLS FOR PRODUCTION ENHANCEMENT IN THE MID-CONTINENT

    SciTech Connect

    Scott Reeves

    2003-03-01

    Stripper gas wells are an important source of domestic energy supply and under constant threat of permanent loss (shut-in) due to marginal economics. In 1998, 192 thousand stripper gas wells produced over a Tcf of gas, at an average rate of less than 16 Mcfd. This represents about 57% of all producing gas wells in the onshore lower-48 states, yet only 8% of production. Reserves of stripper gas wells are estimated to be only 1.6 Tcf, or slightly over 1% of the onshore lower-48 total (end of year 1996 data). Obviously, stripper gas wells are at the very margin of economic sustenance. As the demand for natural gas in the U.S. grows to the forecasted estimate of over 30 Tcf annually by the year 2010, supply from current conventional sources is expected to decline. Therefore, an important need exists to fully exploit known domestic resources of natural gas, including those represented by stripper gas wells. The overall objectives of this project are to develop an efficient and low-cost methodology to broadly categorize the well performance characteristics for a stripper gas field, identify the high-potential candidate wells for remediation, and diagnose the specific causes for well underperformance. With this capability, stripper gas well operators can more efficiently and economically produce these resources and maximize these gas reserves. A further objective is to identify/develop, evaluate and test ''new and novel,'' economically viable remediation options. Finally, it is the objective of this project that all the methods and technologies developed in this project, while being tested in the Mid-Continent, be widely applicable to stripper gas wells of all types across the country. The project activities during the reporting period were: (1) Continued to solicit industry research partners to provide test sites, including Patina Oil and Gas and EOG Resources, each of whom have previously worked with ARI on a similar projects funded by the Gas Technology Institute. Both

  11. SELECTION AND TREATMENT OF STRIPPER GAS WELLS FOR PRODUCTION ENHANCEMENT IN THE MID-CONTINENT

    SciTech Connect

    Scott Reeves

    2003-03-01

    Stripper gas wells are an important source of domestic energy supply and under constant threat of permanent loss (shut-in) due to marginal economics. In 1998, 192 thousand stripper gas wells produced over a Tcf of gas, at an average rate of less than 16 Mcfd. This represents about 57% of all producing gas wells in the onshore lower-48 states, yet only 8% of production. Reserves of stripper gas wells are estimated to be only 1.6 Tcf, or slightly over 1% of the onshore lower-48 total (end of year 1996 data). Obviously, stripper gas wells are at the very margin of economic sustenance. As the demand for natural gas in the U.S. grows to the forecasted estimate of over 30 Tcf annually by the year 2010, supply from current conventional sources is expected to decline. Therefore, an important need exists to fully exploit known domestic resources of natural gas, including those represented by stripper gas wells. The overall objectives of this project are to develop an efficient and low-cost methodology to broadly categorize the well performance characteristics for a stripper gas field, identify the high-potential candidate wells for remediation, and diagnose the specific causes for well underperformance. With this capability, stripper gas well operators can more efficiently and economically produce these resources and maximize these gas reserves. A further objective is to identify/develop, evaluate and test ''new and novel,'' economically viable remediation options. Finally, it is the objective of this project that all the methods and technologies developed in this project, while being tested in the Mid-Continent, be widely applicable to stripper gas wells of all types across the country. The project activities during the reporting period were: (1) Completed both type curve and artificial neural network analysis of the field. Developed list of production enhancement candidates. (2) Made final presentation of results to Oneok in Tulsa (February 26). (3) Made presentations on

  12. The development of extension and magmatism during continent-ocean transition: evidence from Ethiopia

    NASA Astrophysics Data System (ADS)

    Bastow, Ian; Keir, Derek; Booth, Adam; Corti, Giacomo; Magee, Craig; Jackson, Christopher; Wilkinson, Jason

    2016-04-01

    The geological record at rifts and margins worldwide often reveals along-strike variations in volumes of extruded and intruded igneous rocks. These variations may be the result of asthenospheric heterogeneity, variations in rate and timing of extension. Preexisting plate architecture and/or the evolving kinematics of extension during breakup may also influence magmatism strongly. The Ethiopian and Afar Rift systems provide an excellent opportunity to address these issues since they expose, along strike, several sectors of ongoing, asynchronous rift development from embryonic continental rifting in the south to incipient oceanic spreading in the north. A consensus has now emerged from a variety of disciplines in Ethiopia that a considerable proportion of extension in Ethiopia is accommodated by focused dyke intrusion in narrow axial zones, without marked crustal (and plate?) thinning. These "magmatic segments" may mark the final breakup boundary and location of an incipient oceanic spreading centre. However, observations of markedly thinned crust and a pulse in Quaternary-Recent basaltic volcanism within the Danakil Depression have recently been cited as evidence that an abrupt, late stage of localised plate stretching may instead mark the final stages of continent-ocean transition (Bastow & Keir, 2011). We explore this hypothesis using recently-acquired seismic reflection data and accompanying borehole geological constraints from Danakil. Thick sequences of evaporites have been deposited in an asymmetric basin, whose subsidence has been controlled primarily by a major, east dipping normal fault. Surprisingly, no significant magmatism is observed in the upper ~1000m. Age constraints on a potash-bearing sequence presently being mined in the basin point towards rapid basin infill in the last several tens-to-hundreds of thousands of years. Basin formation cannot be easily attributed to the effects of magmata intrusion. Instead, an abrupt, localised, late-stage, plate

  13. A lithospheric profile across northern Taiwan: from arc-continent collision to extension

    NASA Astrophysics Data System (ADS)

    Van Avendonk, Harm J. A.; McIntosh, Kirk D.; Kuo-Chen, Hao; Lavier, Luc L.; Okaya, David A.; Wu, Francis T.; Wang, Chien-Ying; Lee, Chao-Shing; Liu, Char-Shine

    2016-01-01

    During arc-continent collision, buoyant sections of sediments and rifted continental crust from a subducting plate will accrete to the forearc of the upper plate as long as this backstop remains intact. Deformation of the oceanic arc and forearc block may ultimately lead to accretion of these mafic rock units to the new orogen. The Taiwan mountain belt, which formed at ˜6.5 Ma by oblique convergence between the Eurasian passive margin and the overriding Luzon arc in northern Taiwan, offers important insight in this process, since the collision is more advanced in the north than in the south. The incipient stage of arc-collision can be studied in southern Taiwan, while the northern portion of the orogen is presently undergoing collapse due to a flip in the subduction polarity between the Eurasian Plate and the Philippine Sea Plate. In this study, we seismically image the structure of the northern section of the mountain belt with a tomographic inversion. We present marine and land-based seismic refraction data, as well as local earthquake data, from transect T6 of the Taiwan Integrated Geodynamic Research (TAIGER) program across the Taiwan mountain belt and the adjacent Ryukyu arc. Our 2-D compressional seismic velocity model for this transect, which is based on a tomographic inversion of 10 213 P-wave arrival times, shows that the Eurasian crystalline continental crust thickens from ˜24 km in the Taiwan Strait to ˜40 km beneath the eastern Central Range of Taiwan. The detailed seismic velocity structure of the Taiwan mountain belt shows vertical continuity in the upper 15 km, which suggests that rocks are exhumed to the surface here from the middle crust in a near-vertical path. The continental crust of the westernmost Ryukyu arc is almost as thick (˜40 km) as in the adjacent northern Central Range of Taiwan, and it appears to override the leading edge of the Philippine Sea Plate offshore northeastern Taiwan. If we assume that the western Ryukyu arc crust also

  14. Tectonic Evolution of the Banda Arc-Continent Collision in the Timor Region

    NASA Astrophysics Data System (ADS)

    Harris, R. A.

    2011-12-01

    Recent detailed studies of the active Banda arc-continent collision reveal many new features about its tectonic evolution, such as (1) when collision initiated, (2) conditions and age of metamorphism, (3) timing of island emergence and exhumation, (4) how the arc is affected by collision, (5) differences between rock and surface uplift rates, (6) the temporal distribution of strain and (7) natural hazards. (1) The youngest Australian continental margin material incorporated into the Banda orogen is 7-8 Ma in East Timor and 6 Ma in West Timor. (2) Collision-related metamorphic rocks in East Timor yield max. temperatures of 850 °C and pressures of 12 kb. The age of the metamorphism is constrained by zircon U/Pb ages of 6.7 Ma. (3) Island emergence and erosional exhumation is constrained by foraminifera depth vs. age estimates of the transition from deep marine chalk to distal turbidite deposition at 4.2 Ma in East Timor and younger to the east and west. Exhumation of metamorphic rocks is constrained by amphibole with Ar/Ar cooling ages of ~6 Ma (~525°C), zircons with U/He ages of 4.5 Ma (215°C), and apatite with U/He ages of 3.5 Ma (90°C). Younger exhumation ages are found to the south. (4) Contamination of the volcanic arc by subducted continental material is first detected in eroded arc islands near East Timor at 5 Ma. The age of contamination youngs both east and west in less eroded, active arc islands. The main arc edifice north of East Timor is abandoned at 1-3 Ma and is shifted 30 km to the north by the Wetar backarc thrust. A new volcanic center emerges further north. (5) Coral terraces encrust the rising islands and yield highly variable uplift rates, with some as high as 1.5 mm/a. The highest rates correspond with active thrust faults and diapirs. Rock uplift rates associated with exhumation of the schist belt are as high as 8 mm/a. (6) GPS velocities in the most advanced part of the collision (central Timor) show that 70% of the 70 mm/a convergence

  15. Physical climatology of Indonesian maritime continent: An outline to comprehend observational studies

    NASA Astrophysics Data System (ADS)

    Yamanaka, Manabu D.

    2016-09-01

    The Indonesian maritime continent (IMC) is a miniature of our land-sea coexisting planet Earth. Firstly, without interior activity, the Earth becomes an even-surfaced "aqua-planet" with both atmosphere and ocean flowing almost zonally, and solar differential heating generates (global thermal tides and) Hadley's meridional circulations with the inter-tropical convergence zone (ITCZ) along the equator as observed actually over the open (Indian and Pacific) oceans on the both sides of the IMC. The ITCZ involves intraseasonal variations or super cloud clusters moving eastward with hierarchical substructures moving also westward. Secondly, the lands and seas over the actual Earth have been keeping the area ratio of 3:7 (similar to that of islands and inland/surrounding seas in the IMC), but their displacements have produced the IMC near the equator, which turns equatorial Pacific easterly ocean current northward (Kuroshio) and reflects equatorial oceanic waves that affect coupled ocean-atmosphere interannual variations such as ENSO and IOD, or displacements of Walker's zonal circulations. Thirdly, because the IMC consists of many large/small islands with very long coastlines, many narrow straits control the global (Pacific to Indian) ocean circulation, and the land-sea heat capacity contrasts along the coastlines generate the world's largest rainfall with diurnal cycles (sea-land breeze circulations). The diurnal cycles are dominant even in the rainy season (austral summer in Jawa and Bali), because rainfall-induced sprinkler-like land cooling reverses the trans-coastal temperature gradient before sunrise, and subsequent clear sky on land until around noon provides solar heating dependent on season. These processes lead to rapid land/hydrosphere-atmosphere water exchange, local air pollutant washout, and transequatorial boreal winter monsoon (cold surge). In El Niño years, for example, the cooler sea-surface temperature suppresses the morning coastal-sea rainfall, and

  16. Improving time to continence after robot-assisted laparoscopic prostatectomy: augmentation of the total anatomic reconstruction technique by adding dynamic detrusor cuff trigonoplasty and suprapubic tube placement.

    PubMed

    Tewari, Ashutosh K; Ali, Adnan; Ghareeb, George; Ludwig, Wesley; Metgud, Sheela; Theckumparampil, Nithin; Takenaka, Atsushi; Chugtai, Bilal; Shrivastava, Abhishek; Kaplan, Steve A; Leung, Robert; Paryani, Rahul; Grushow, Siobhan; Durand, Matthieu; Peyser, Alexandra; Chopra, Sameer; Harneja, Niyati; Lee, Richard K; Herman, Michael; Robinson, Brian; Shevchuck, Maria M

    2012-12-01

    After robot-assisted laparoscopic prostatectomy, total anatomic reconstruction (TR) with the additions of a circumapical urethral dissection, a dynamic detrusor cuff trigonoplasty, and placement of a suprapubic catheter was performed in 49 patients from June to July 2012. Continence at 6 weeks after catheter removal was assessed for an initial group of 23 patients, and also at 2 weeks in an additional 26 patients who most recently had undergone surgery. Follow-up appointments and telephone interviews were used to assess pad use and continence. Of the initial 23 patients receiving the modified TR, 60.9% had 0 pad use at 6 weeks. By 2 weeks, 65.4% of the most recent 26 patients operated on achieved continence with 0-1 pad use. Preservation and reconstruction of the pelvic floor and supporting bladder structures leads to an earlier return of continence. These key steps need to be validated and confirmed in larger and randomized trials. PMID:23230868

  17. The continent-ocean transition of the rifted South China continental margin

    NASA Astrophysics Data System (ADS)

    Cameselle, Alejandra L.; Ranero, César R.; Franke, Dieter; Barckhausen, Udo

    2014-05-01

    The continent to ocean transition (COT) architecture of rifted margins represents a key aspect in the study of the variability of different rifting systems and thus, to understand lithospheric extension and final break-up processes. We used 2250 km of reprocessed multichannel seismic data along 4 regional lines and magnetic data acquired across the NW South China continental margin to investigate a previously poorly defined COT. The along-strike structure of the NW subbasin of the South China Sea presents different amounts of extension allowing the study of conjugate pairs of continental margins and their COT in a relative small region. The time-migrated seismic sections allow us to interpreted clear continental and oceanic domains from differences in internal reflectivity, faulting style, fault-block geometry, the seismic character of the top of the basement, the geometry of sediment deposits, and Moho reflections. The continental domain is characterized by arrays of normal faults and associated tilted blocks overlaid by syn-rift sedimentary units. The Moho is imaged as sub-horizontal reflections that define a fairly continuous boundary typically at 8-10 s TWT. Estimation of the thickness of the continental crust using 6 km/s average velocity indicates a ~22 km-thick continental crust under the uppermost slope thinning abruptly to ~9-6 km under the lower slope. The oceanic crust has a comparatively highly reflective top of basement, little-faulting, not discernible syn-tectonic strata, and fairly constant thickness (4-8 km) over tens of km distance defined by usually clear Moho reflections. The COT can be very well defined based on MSC images and occurs across a ~5-10 km narrow zone. Rifting in the NW subbasin resulted in asymmetric conjugate margins. Arrays of tilted fault blocks covered by abundant syn-rift sediment are displayed across the northwestern South China continental margin, whereas the conjugate Macclesfield Bank margin shows abrupt thinning and

  18. High amplitude continous infrasonic signals recorded on the Romanian Black Sea coast

    NASA Astrophysics Data System (ADS)

    Moldovan, Iren-Adelina; Emilian Toader, Victorin; Septimiu Moldovan, Adrian

    2014-05-01

    locations in order to obtain data to be compared with the data recorded at Mangalia site. The system was firstly placed in the Dobrogea Seismological Observatory, from Eforie, situated at 500m from the sea front. Similar signals appeared on the recordings around 2Hz, but without higher frequency harmonics. The second location of the portable recording unit was at Izvoarele, Galati County, at 128km from the Black Sea coast line, and 15km away from the Danube River. The recordings presented no high amplitude continous signals above 2Hz, similar to other recordings obtained with the Romanian Chaparal and MB-AZEL2007 Infrasound Network. In the last days of 2013, the system was moved in a new place, at Vrancioaia site, on the top of a hill, with steep slopes both in front and back of the measuring point. A new interesting signal was revealed. The corroboration of the infrasound recordings and spectrograms with local meteorological data, wind speed, magnitude of sea waves or atmospheric electric field amplitude, could yield important scientific conclusions, beneficial both for authorities and academic media.

  19. Role of Multi-scale Physical Processes in the Spatial and Temporal Variability of Rainfall over the Maritime Continent

    NASA Astrophysics Data System (ADS)

    Qian, J.; Robertson, A. W.; Moron, V.

    2009-12-01

    We studied the role of multiscale physical processes of ENSO, monsoon, and diurnal cycle on the spatial distribution and temporal variability of rainfall over the Maritime Continent by using high-resolution observations and regional climate model simulations. It is found that precipitation over the Maritime Continent is mostly concentrated over islands. Analysis of the diurnal cycles of precipitation and winds indicates that this is predominantly caused by sea-breeze convergence over islands, reinforced by mountain-valley winds, and further amplified by the cumulus merger processes. The climate variability over the Maritime Continent is found spatially heterogeneous. Besides the well-known anomalous dry conditions that characterize the dry and transitioning seasons during an El Nino year, analysis of regional model output reveals a wet south versus dry north dipolar structure of rainfall anomalies over Java and a wet west versus dry east dipolar pattern of rainfall anomalies over Borneo associated with El Nino during the peak rainy season. Climate Predictability Tools (CPT) are used to analyze the relationship between the sea surface temperature and station rain gauge and modeling data and confirm these ENSO-related dipolar patterns. Modeling experiments indicate that these dipolar structures of rainfall anomalies are caused by the interaction of the El Nino-induced monsoonal wind anomalies and the island- and mountain- induced local diurnal cycle of winds and precipitation. In the wet season in El Nino years, large-scale anomalous southeasterly winds are in opposite direction to the climatological northwesterly monsoon, thus reduce the monsoon wind speed. Then the monsoon intensity affects the local diurnal cycle of land-sea breezes and mountain-valley winds and the propagation of rainfall maxima. A weather typing cluster method is also used to study the impacts of ENSO and monsoon on the local rainfall variability.

  20. Medical devices; gastroenterology-urology devices; nonimplanted, peripheral electrical continence device. Food and Drug Administration, HHS. Final rule.

    PubMed

    2000-04-01

    The Food and Drug Administration (FDA) is classifying the nonimplanted, peripheral electrical continence device into class II (special controls). The special controls that will apply to this device are set forth below. The agency is taking this action in response to a petition submitted under the Federal Food, Drug, and Cosmetic Act (the act) as amended by the Medical Device Amendments of 1976, the Safe Medical Devices Act of 1990, and the Food and Drug Administration Modernization Act of 1997. The agency is classifying this device into class II (special controls) in order to provide a reasonable assurance of safety and effectiveness of the device. PMID:11010624

  1. Perioperative and continence outcomes of robotic radical prostatectomy in elderly Indian men (≥70 years): A sub-group analysis

    PubMed Central

    Yadav, Rajiv; Gupta, Narmada P.; Akpo, Emmanuel E.; Kumar, Anand

    2015-01-01

    Introduction: Many healthy elderly Indian men seek surgical treatment for localized prostate cancer. Quite often, radical surgery is not offered to the patients over 70 years of age due to the perception of increased side-effects and complications. We have previously reported our results of robotic radical prostatectomy in a study comprising 150 Indian patients, where almost a quarter of patients were elderly. This subgroup analysis was therefore focused on evaluating perioperative and continence outcomes in elderly men (≥70 years) with localized prostate cancer. Materials and Methods: Between April 2010 and August 2013, 153 men had robot-assisted radical prostatectomy performed by two surgeons. Of the 150 men analyzed, 39 (26%) were aged ≥70 years. All patients underwent robotic prostatectomy using a 4 arm da Vinci surgical system. Pre-operative, intraoperative and post-operative parameters were studied. Check cystogram was performed in all patients prior to catheter removal. Complications were categorized using the Clavien-Dindo classification system. Continence was defined as use of “no pad” or security liner only. All data were recorded prospectively and analyzed using SPSS version 20. Results: There were no significant intraoperative or perioperative complications in this group. Median blood loss during surgery was 150 mL. None of the patient required blood transfusion. There were two minor complications (5.1%) within the first 30 days of surgery: Minimal anastomotic site leak (one patient) requiring replacement and prolongation of Foley's drainage by 1 week and ileus (one patient). No patient had any cardiopulmonary or vascular complications in the post-operative period. The median duration of hospital stay was 3 days. The median duration of catheterization was 7 days. No patient had problem of bladder neck stenosis in the follow-up period. At 1 month, 3 months, 6 months and 1 year of follow-up, 66.7% (n = 26), 74.3% (n = 29), 87.9% (n = 34) and 94

  2. The longevity of Archean mantle residues in the convecting upper mantle and their role in young continent formation

    NASA Astrophysics Data System (ADS)

    Liu, Jingao; Scott, James M.; Martin, Candace E.; Pearson, D. Graham

    2015-08-01

    The role played by ancient melt-depleted lithospheric mantle in preserving continental crust through time is critical in understanding how continents are built, disrupted and recycled. While it has become clear that much of the extant Archean crust is underpinned by Archean mantle roots, reports of Proterozoic melt depletion ages for peridotites erupted through Phanerozoic terranes raise the possibility that ancient buoyant lithospheric mantle acts as a "life-raft" for much of the Earth's continental crust. Here we report the largest crust-lithospheric mantle age decoupling (∼2.4 Ga) so far observed on Earth and examine the potential cause for such extreme age decoupling. The Phanerozoic (<300 Ma) continental crust of West Otago, New Zealand, is intruded by Cenozoic diatremes that have erupted cratonic mantle-like highly depleted harzburgites and dunites. These peridotites have rhenium depletion Os model ages that vary from 0.5 to 2.7 Ga, firmly establishing the record of an Archean depletion event. However, the vast range in depletion ages does not correlate with melt depletion or metasomatic tracer indices, providing little support for the presence of a significant volume of ancient mantle root beneath this region. Instead, the chemical and isotopic data are best explained by mixing of relict components of Archean depleted peridotitic mantle residues that have cycled through the asthenosphere over Ga timescales along with more fertile convecting mantle. Extensive melt depletion associated with the "docking" of these melt residues beneath the young continental crust of the Zealandia continent explains the decoupled age relationship that we observe today. Hence, the newly formed lithospheric root incorporates a mixture of ancient and modern mantle derived from the convecting mantle, cooled and accreted in recent times. We argue that in this case, the ancient components played no earlier role in continent stabilization, but their highly depleted nature along with

  3. Urinary Continence Outcomes after Puboprostatic Ligament Preserving Open Retropubic Radical Prostatectomy at a Sub-Saharan Hospital

    PubMed Central

    Kaggwa, S.; Galukande, M.

    2014-01-01

    Background. Open retropubic radical prostatectomy is a commonly performed procedure for clinically localized prostate cancer. The demand for high level functional outcomes after therapy is increasing especially for young age patients; in this regard refinements in the surgical technique have been made. There is limited data to show the success of some of these refinements in resource limited settings. Methods. A retrospective clinical study was performed over a 2-year period at Mengo Hospital, Urology Unit. Men with clinically localized prostate cancer and who consented to the procedure were eligible and were recruited. Consequently excluded were those that turned out to have advanced disease and those with severe comorbidities. Patients were followed up for 3 months after surgery. Data was entered using SPSS version 17 and analyzed. Results. A total of 24 men with clinically localized prostate cancer underwent open retropubic puboprostatic ligament preserving radical prostatectomy technique. Mean age was 66, range 54–75 years. Outcome. Two patients had stress incontinence and three were incontinent at 3 months. The urinary continence recovery rate was 19/24 (79%) at 3 months. Conclusion. Preservation of the puboprostatic ligament in open retropubic radical prostatectomy was associated with rapid and a high rate of return to urinary continence among men with clinically localized disease.

  4. Rarity of a top predator triggers continent-wide collapse of mammal prey: dingoes and marsupials in Australia.

    PubMed

    Johnson, Christopher N; Isaac, Joanne L; Fisher, Diana O

    2007-02-01

    Top predators in terrestrial ecosystems may limit populations of smaller predators that could otherwise become over abundant and cause declines and extinctions of some prey. It is therefore possible that top predators indirectly protect many species of prey from excessive predation. This effect has been demonstrated in some small-scale studies, but it is not known how general or important it is in maintaining prey biodiversity. During the last 150 years, Australia has suffered the world's highest rate of mammal decline and extinction, and most evidence points to introduced mid-sized predators (the red fox and the feral cat) as the cause. Here, we test the idea that the decline of Australia's largest native predator, the dingo, played a role in these extinctions. Dingoes were persecuted from the beginning of European settlement in Australia and have been eliminated or made rare over large parts of the continent. We show a strong positive relationship between the survival of marsupials and the geographical overlap with high-density dingo populations. Our results suggest that the rarity of dingoes was a critical factor which allowed smaller predators to overwhelm marsupial prey, triggering extinction over much of the continent. This is evidence of a crucial role of top predators in maintaining prey biodiversity at large scales in terrestrial ecosystems and suggests that many remaining Australian mammals would benefit from the positive management of dingoes. PMID:17164197

  5. Variations in the Delivery of SI to the Oceans from the Continents: Implications of a Dynamic Terrestrial SI Cycle

    NASA Astrophysics Data System (ADS)

    Frings, P.; Conley, D. J.; Clymans, W.; Fontorbe, G.; De La Rocha, C. L.

    2014-12-01

    A common assumption is that the modern day continental Si cycle is at steady-state. However, a new paradigm is emerging regarding the terrestrial biogeochemical Si cycle and its importance. We now know that the terrestrial Si cycle is strongly biologically mediated, which creates and recycles a pool of reactive Si in soils and sediments that ultimately buffers the export of dissolved silicate (DSi) to the oceans. Our recent results show that imbalances in the continental Si pool on millennial scales may have caused systematic mis-estimation of silicate weathering rates, particularly when using river chemistry at large spatial scales to calculate weathering rates. Quantifying this imbalance is essential to understand ocean-terrestrial biogeochemical interactions. On short (human) timescales large-scale changes in land cover, erosion and eutrophication have significantly altered the fluvial flux of Si. Likewise, periods of glacial-interglacial transitions produce new weathering products from the continents with subsequent impacts on oceanic DSi. Over still longer timescales significant changes in fluvial Si fluxes have probably occurred with large-scale changes in chemical weathering due to orogeny, climate change, the emplacement of large igneous provinces, or changes in volcanic activity. We will discuss the timescale dependency of processes and the assumption of steady state. In addition, we will examine how a changing terrestrial Si cycle impacts the ocean Si cycle. Finally, we will address unresolved questions regarding the delivery of Si to the oceans from the continents.

  6. Stomatal controls on vegetation productivity and water cycling across the African continent in a warmer and CO2 enriched climate

    NASA Astrophysics Data System (ADS)

    Sato, H.; Kumagai, T.; Takahashi, A.; Katul, G. G.

    2014-12-01

    General Circulation Models (GCMs) forecast higher vapor pressure deficit (VPD) but unchanged relative humidity (RH) in future climates. A recent literature survey revealed some 50% of Earth System (ESMs) and Land Surface (LSMs) Models embedded within GCMs employ RH as an atmospheric aridity index when describing stomatal conductance (gs) while the remaining 50% employ VPD. Propagating the consequences of using RH or VPD in gs models on water cycling and vegetation productivity in future climates in one of the most vulnerable continents, the African continent, remains to be explored. Using process-based global dynamic vegetation model runs, changes in the hydrological cycle and concomitant vegetation productivity for a 21st century projected climate are conducted by altering only gs responses to VPD or RH while maintaining all other formulations unaltered. In the simulations under warming trend of the 21st century, both stomata functions of VPD and RH result in nearly identical changes in the geographic pattern of Gross Primary Production (GPP). However, continental total of GPP becomes bit larger for the VPD function than for the RH function. Transpiration rates becomes lower resulting in water-use-efficiency becoming higher by some 13% for the VPD function when compared to its RH counterpart.

  7. A new look at the structure of the Antarctic continent from P wave travel times and adaptively parameterized tomography

    NASA Astrophysics Data System (ADS)

    Bishop, J. A.; Hansen, S. E.

    2011-12-01

    The geologic processes shaping the Antarctic continent are widely debated. In order to evaluate candidate models for the region, tomographic images that highlight the upper mantle structure are crucial; however, existing continental-scale tomography models for Antarctica lack sufficient resolution to delineate important, diagnostic features. Most tomographic models are generated using a uniformly-spaced grid over the entire study area, which can result in reduced resolution by over-emphasizing poorly sampled areas of the model and not providing enough emphasis in areas containing pertinent small-scale structure. Alternatively, the adaptively parameterized tomography method constructs a more condensed grid spacing in areas with better seismic ray coverage, thereby allowing such regions to be better resolved, while at the same time limiting the resolution of features in areas with less seismic coverage. By generating such a model for Antarctica, this approach allows candidate geologic models to be more critically assessed, resulting in a better understanding not only of Antarctic geodynamic processes but also of important processes on a global scale. In addition, the resulting tomographic model will impact thermal lithospheric estimates used to characterize ice sheet dynamics and climate-ice models, which are important in understanding the cooling history of the continent. Preliminary results will be shown.

  8. Training through gametherapy promotes coactivation of the pelvic floor and abdominal muscles in young women, nulliparous and continents

    PubMed Central

    Silva, Valeria Regina; Riccetto, Cássio; Martinho, Natalia Miguel; Marques, Joseane; Carvalho, Leonardo Cesar; Botelho, Simone

    2016-01-01

    ABSTRACT Introduction and objectives: Several studies have been investigated co-activation can enhance the effectveness of PFM training protocols allowing preventive and therapeutic goals in pelvic floor dysfunctions. The objective of the present study was to investigate if an abdominal-pelvic protocol of training (APT) using gametherapy would allow co-activation of PFM and transversus abdominis/oblique internal (TrA/OI) muscles. Patients and methods: Twenty-five nulliparous, continent, young females, with median age 24.76 (±3.76) years were evaluated using digital palpation (DP) of PFM and surface electromyography of PFM and TrA/OI simultaneously, during maximal voluntary contraction (MVC), alternating PFM and TrA/OI contraction requests. All women participated on a supervised program of APT using gametherapy, that included exercises of pelvic mobilization associated to contraction of TrA/OI muscles oriented by virtual games, for 30 minutes, three times a week, in a total of 10 sessions. Electromyographic data were processed and analyzed by ANOVA - analysis of variance. Results: When MVC of TrA/OI was solicited, it was observed simultaneous increase of electromyographic activity of PFM (p=0.001) following ATP. However, EMG activity did not change significantly during MVC of PFM. Conclusion: Training using gametherapy allowed better co-activation of pelvic floor muscles in response to contraction of TrA, in young nulliparous and continent women. PMID:27564290

  9. Magnetic Signatures and Curie Surface Trend Across an Arc-Continent Collision Zone: An Example from Central Philippines

    NASA Astrophysics Data System (ADS)

    Manalo, Pearlyn C.; Dimalanta, Carla B.; Ramos, Noelynna T.; Faustino-Eslava, Decibel V.; Queaño, Karlo L.; Yumul, Graciano P.

    2016-05-01

    Ground and aeromagnetic data are combined to characterize the onshore and offshore magnetic properties of the central Philippines, whose tectonic setting is complicated by opposing subduction zones, large-scale strike-slip faulting and arc-continent collision. The striking difference between the magnetic signatures of the islands with established continental affinity and those of the islands belonging to the island arc terrane is observed. Negative magnetic anomalies are registered over the continental terrane, while positive magnetic anomalies are observed over the Philippine Mobile Belt. Several linear features in the magnetic anomaly map coincide with the trace of the Philippine Fault and its splays. Power spectral analysis of the magnetic data reveals that the Curie depth across the central Philippines varies. The deepest point of the magnetic crust is beneath Mindoro Island at 32 km. The Curie surface shallows toward the east: the Curie surface is 21 km deep between the islands of Sibuyan and Masbate, and 18 km deep at the junction of Buruanga Peninsula and Panay Island. The shallowest Curie surface (18 km) coincides with the boundary of the arc-continent collision, signifying the obduction of mantle rocks over the continental basement. Comparison of the calculated Curie depth with recent crustal thickness models reveals the same eastwards thinning trend and range of depths. The coincidence of the magnetic boundary and the density boundary may support the existence of a compositional boundary that reflects the crust-mantle interface.

  10. Study on the location and fit of continents in western central Pangea with a focus on the Mediterranean and North Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Kwon, Ohyeok; Cheong, Hyeong-Bin

    2015-04-01

    Since Alfred Wegener proposed the theory of continental drift more than a century ago, continuous effort to reconstruct the super continent Pangea has been carried out paleo-geographically during past several decades. Although a remarkable success has been achieved, there remains still a great uncertainty on the precise location and fits of the continents that constitute the Pangea. While the fits are recognized as quite complete for Gondwana, the northern part of Pangea, the fits for Laurasia which contains North Ameraica and Eurasia, are left with a lot of improvement. What the two giant continents look like when they were fitted to form the Pangea is also a unsolved question. Several hypothesis for the fits of Laurasia and Gondwana have been raised, and the scenarios of Pangea A1, Pangea A2, Pangea B, and Pangea C were proposed hitherto. Recently, an updated version very close to Pangea A2 was suggested by authors including Van der Voo, Trond H. Torsvik, which have improved several deficiencies of the Pangea A2. However, it was found that the new scenario cannot be fully supported by the paleomagnetism data. Furthermore, it is not in complete agreement with previous paleogeological surveys on major geological features such as Variscan and Caledonian orogenic belt, indicating that a more sophisticated scenario is needed still for the Pangea. The purpose of this study is to reconstruct the continents in western central Pangea with a focus on the Mediterranean and North Atlantic Ocean. A new fit of continents to form the Pangea is proposed, where the continents are fitted with enhanced accuracy compared to other models of Pangea particularly for the Mediterranean Sea, central America, Iran Plateau etc.. The results suggest that the continents were not distorted significantly on the process of drifting and merging during the past 200 million years.

  11. Estimating Carbon Dioxide Fluxes from Sources and Sinks in the Mid-Continent Intensive using Inventories and Satellite Remote Sensing

    NASA Astrophysics Data System (ADS)

    West, T. O.; Bandaru, V.; Brandt, C. C.; Schuh, A. E.; Gurney, K. R.; Heath, L. S.; Izaurralde, R. C.; Liu, S.; Li, Z.; Ogle, S. M.

    2009-12-01

    Estimates of carbon dioxide sources and sinks have been compiled from numerous models and national inventories. Flux estimates include those for cropland, grassland, and forest biomass; cropland and grassland soils; fossil-fuel emissions; emissions from livestock and humans; and movement of carbon into and out of the region. Estimates have been scaled to coincide with entities responsible for respective carbon fluxes and for consistent estimates among flux sources. We will present methods used to scale fluxes using satellite remote sensing data and present comprehensive results of carbon fluxes within a ten-state region surrounding the State of Iowa. Results will be compared to previous carbon flux estimates produced under the Mid-Continent Intensive Interim synthesis. We will discuss significant changes in estimation methods and variability associated with components of the current estimates.

  12. How the growth and freeboard of continents may relate to geometric and kinematic parameters of mid-ocean spreading ridges

    USGS Publications Warehouse

    Howell, D.G.

    1989-01-01

    If the volume of continents has been growing since 4 Ga then the area of the ocean basins must have been shrinking. Therefore, by inferring a constant continental freeboard, in addition to constant continental crustal thicknesses and seawater volume, it is possible to calculate the necessary combinations of increased ridge lengths and spreading rates required to displace the seawater in the larger oceans of the past in order to maintain the constant freeboard. A reasonable choice from the various possibilities is that at 4 Ga ago, the ridge length and spreading rates were ca. 2.5 times greater than the averages of these parameters during the past 200 Ma. By 2.5 Ga ago the ridge length and spreading rate decreased to about 1.8 times the recent average and by 1 Ga ago these features became reduced to approximately 1.4 times recent averages. ?? 1989.

  13. Dynamical implications of single-sided subduction and floating continents in global self-consistent models of mantle convection

    NASA Astrophysics Data System (ADS)

    Crameri, F.; Rolf, T.; Tackley, P. J.

    2012-12-01

    Previous global dynamical models using a visco-plastic rheology are able to reproduce some aspects of plate tectonics and mantle convection. However, these models still fail to reproduce some first-order features of plate tectonics, for example Earth-like one-sided subduction. The usual assumption these models make inhibits development of surface topography. Schmeling et al. (2008) and Crameri et al. (2012a) showed that it is necessary to include a proper free surface in numerical models in order to reproduce laboratory results and to guarantee a physically accurate topographic evolution, respectively. According to these benchmark studies, mimicking a free surface by inserting a weak, zero density layer on top of the crust is an adequate approach if (a) it is sufficiently thick and (b) has a sufficiently low viscosity. As shown in Crameri et al. (2012b), this model extension directly leads to dynamically self-consistent single-sided subduction. On the other hand, Rolf & Tackley (2011) showed that the presence of pre-existing, floating continents plays an important role on the evolution of plate tectonics: convective stresses may be focused at the rheological boundary between continent and ocean, which facilitates the formation of plate boundaries and makes the Earth-like, mobile lid mode of plate tectonics easier to observe. We here study the effect of (a) the mode of subduction and (b) the presence of strong Archean cratons on the dynamics of Earth's interior using Cartesian 2-D to spherical 3-D global, fully dynamic mantle convection models with self-consistent plate tectonics. For this we use the finite volume multi-grid code STAGYY (Tackley 2008). While in the mobile lid (plate tectonic like) regime, our model shows that single-sided subduction has strong implications on Earth's interior such as its rms. velocity and mantle flow distribution. Continents might support a model that produces continuously evolving single-sided subduction and thus allow for

  14. GPS Observation of Fast-moving Continent-size Traveling TEC Pulsations at the Start of Geomagnetic Storms

    NASA Astrophysics Data System (ADS)

    Pradipta, R.; Valladares, C. E.; Doherty, P. H.

    2014-12-01

    Using network of GPS receiver stations in North and South America, we have recently observed fast-moving continent-size traveling plasma disturbances in the mapped total electron content (TEC) data. These space plasma disturbances occurred at the beginning of geomagnetic storms, immediately after the storm's suddent commencement (SSC) and prior to the appearance of large-scale traveling ionospheric disturbances (LSTIDs) from the auroral regions. More specifically, these supersize TEC perturbations were observed when the IMF Bz was oscillating between northward and southward directions. They were found to propagate zonally westward with a propagation speed of 2-3 km/s, if projected onto an ionospheric-equivalent altitude of 350 km. Based on their general characteristics and comparison with ground-based ionosonde data, we interpret these TEC pulsations as ion drift waves in the magnetosphere/plasmasphere that propagate azimuthally inside the GPS orbit.

  15. Transfer of nutrients and labile metals from the continent to the sea by a small Mediterranean river.

    PubMed

    Nicolau, R; Galera-Cunha, A; Lucas, Y

    2006-04-01

    The contribution of small watersheds to coastal pollution in Mediterranean areas is still poorly known, and presents great variations along an hydrological year. This work deals with the characterization and quantification of Al, Fe, Zn, Cu, Pb, Si, NO(3)(-) and organic carbon transported from the continent to the sea by a small coastal river in the French Mediterranean area. Transported species were characterized both during rainy and dry periods. During non-rainy periods (base-flow), waters showed a low content of contaminants, whereas during heavy rain events, following dry periods, some metals and organic carbon reached concentrations that could affect biological populations. These contaminants were mainly found in the particulate fraction, originating from the runoff of surface waters, which represents the main process of pollution in urban areas. PMID:16213558

  16. A report from the 42nd Annual Meeting of the International Continence Society (October 15-19 - Beijing, China).

    PubMed

    Rabasseda, X

    2012-11-01

    As Beijing was selected as the site for this year's International Continence Society (ICS) meeting, crowds of locals navigating through the subway train lines and tourists lining up for access to the Forbidden City and other landmarks were joined by a less numerous but a still significant number of researchers, scientists and practitioners working on urinary tract diseases and disorders going to the China National Convention Center to attend the podium and poster sessions. Located next to the Bird's Nest Olympic stadium and offering grand views over the Olympic park from the upper floor where non-discussion posters were displayed, the modern facilities allowed for a smooth, seamless meeting during which a number of highly relevant new findings were discussed. The following report summarizes selected presentations on pharmacotherapy and drug candidates for overactive bladder and other common diseases of the urinary tract. PMID:23170310

  17. An empirical investigation on different methods of economic growth rate forecast and its behavior from fifteen countries across five continents

    NASA Astrophysics Data System (ADS)

    Yin, Yip Chee; Hock-Eam, Lim

    2012-09-01

    Our empirical results show that we can predict GDP growth rate more accurately in continent with fewer large economies, compared to smaller economies like Malaysia. This difficulty is very likely positively correlated with subsidy or social security policies. The stage of economic development and level of competiveness also appears to have interactive effects on this forecast stability. These results are generally independent of the forecasting procedures. Countries with high stability in their economic growth, forecasting by model selection is better than model averaging. Overall forecast weight averaging (FWA) is a better forecasting procedure in most countries. FWA also outperforms simple model averaging (SMA) and has the same forecasting ability as Bayesian model averaging (BMA) in almost all countries.

  18. Analysis of pan-African Centres of excellence in health innovation highlights opportunities and challenges for local innovation and financing in the continent.

    PubMed

    Nwaka, Solomon; Ochem, Alexander; Besson, Dominique; Ramirez, Bernadette; Fakorede, Foluke; Botros, Sanaa; Inyang, Uford; Mgone, Charles; Adae-Mensah, Ivan; Konde, Victor; Nyasse, Barthelemy; Okole, Blessed; Guantai, Anastasia; Loots, Glaudina; Atadja, Peter; Ndumbe, Peter; Sanou, Issa; Olesen, Ole; Ridley, Robert; Ilunga, Tshinko

    2012-01-01

    A pool of 38 pan-African Centres of Excellence (CoEs) in health innovation has been selected and recognized by the African Network for Drugs and Diagnostics Innovation (ANDI), through a competitive criteria based process. The process identified a number of opportunities and challenges for health R&D and innovation in the continent: i) it provides a direct evidence for the existence of innovation capability that can be leveraged to fill specific gaps in the continent; ii) it revealed a research and financing pattern that is largely fragmented and uncoordinated, and iii) it highlights the most frequent funders of health research in the continent. The CoEs are envisioned as an innovative network of public and private institutions with a critical mass of expertise and resources to support projects and a variety of activities for capacity building and scientific exchange, including hosting fellows, trainees, scientists on sabbaticals and exchange with other African and non-African institutions. PMID:22838941

  19. Analysis of pan-African Centres of excellence in health innovation highlights opportunities and challenges for local innovation and financing in the continent

    PubMed Central

    2012-01-01

    A pool of 38 pan-African Centres of Excellence (CoEs) in health innovation has been selected and recognized by the African Network for Drugs and Diagnostics Innovation (ANDI), through a competitive criteria based process. The process identified a number of opportunities and challenges for health R&D and innovation in the continent: i) it provides a direct evidence for the existence of innovation capability that can be leveraged to fill specific gaps in the continent; ii) it revealed a research and financing pattern that is largely fragmented and uncoordinated, and iii) it highlights the most frequent funders of health research in the continent. The CoEs are envisioned as an innovative network of public and private institutions with a critical mass of expertise and resources to support projects and a variety of activities for capacity building and scientific exchange, including hosting fellows, trainees, scientists on sabbaticals and exchange with other African and non-African institutions. PMID:22838941

  20. Large-scale distribution of CH4 in the western North Pacific: Sources and transport from the Asian continent

    NASA Astrophysics Data System (ADS)

    Bartlett, Karen B.; Sachse, Glen W.; Slate, Thomas; Harward, Charles; Blake, Donald R.

    2003-10-01

    Methane (CH4) mixing ratios in the northern Pacific Basin were sampled from two aircraft during the TRACE-P mission (Transport and Chemical Evolution over the Pacific) from late February through early April 2001 using a tunable diode laser system. Described in more detail by [2003], the mission was designed to characterize Asian outflow to the Pacific, determine its chemical evolution, and assess changes to the atmosphere resulting from the rapid industrialization and increased energy usage on the Asian continent. The high-resolution, high-precision data set of roughly 13,800 CH4 measurements ranged between 1602 ppbv in stratospherically influenced air and 2149 ppbv in highly polluted air. Overall, CH4 mixing ratios were highly correlated with a variety of other trace gases characteristic of a mix of anthropogenic industrial and combustion sources and were strikingly correlated with ethane (C2H6) in particular. Averages with latitude in the near-surface (0-2 km) show that CH4 was elevated well above background levels north of 15°N close to the Asian continent. In the central and eastern Pacific, levels of CH4 were lower as continental inputs were mixed horizontally and vertically during transport. Overall, the correlation between CH4 and other hydrocarbons such as ethane (C2H6), ethyne (C2H2), and propane (C3H8) as well as the urban/industrial tracer perchloroethene (C2Cl4), suggests that for CH4 colocated sources such as landfills, wastewater treatment, and fossil fuel use associated with urban areas dominate regional inputs at this time. Comparisons between measurements made during TRACE-P and those of PEM-West B, flown during roughly the same time of year and under a similar meteorological setting 7 years earlier, suggest that although the TRACE-P CH4 observations are higher, the changes are not significantly greater than the increases seen in background air over this time interval.

  1. Assessing Climatic Impacts due to Land Use Change over Southeast Asian Maritime Continent base on Mesoscale Model Simulations

    NASA Astrophysics Data System (ADS)

    Feng, N.; Christopher, S. A.; Nair, U. S.

    2014-12-01

    Due to increasing urbanization, deforestation, and agriculture, land use change over Southeast Asia has dramatically risen during the last decades. Large areas of peat swamp forests over the Southeast Asian Maritime Continent region (10°S~20°N and 90°E~135°E) have been cleared for agricultural purposes. The Center for Remote Imaging, Sensing and Processing (CRISP) Moderate Resolution Imaging Spectroradiometer (MODIS) derived land cover classification data show that changes in land use are dominated by conversion of peat swamp forests to oil palm plantation, open lowland or lowland mosaic categories. Nested grid simulations based on Weather Research Forecasting Version 3.6 modelling system (WRFV3.6) over the central region of the Sarawak coast are used to investigate the climatic impacts of land use change over Maritime Continent. Numerical simulations were conducted for August of 2009 for satellite derived land cover scenarios for years 2000 and 2010. The variations in cloud formation, precipitation, and regional radiative and non-radiative parameters on climate results from land use change have been assessed based on numerical simulation results. Modelling studies demonstrate that land use change such as extensive deforestation processes can produce a negative radiative forcing due to the surface albedo increase and evapotranspiration decrease, while also largely caused reduced rainfall and cloud formation, and enhanced shortwave radiative forcing and temperature over the study area. Land use and land cover changes, similar to the domain in this study, has also occurred over other regions in Southeast Asia including Indonesia and could also impact cloud and precipitation formation in these regions.

  2. Origin and development of plains-type folds in the mid-continent (United States) during the late Paleozoic

    USGS Publications Warehouse

    Merriam, D.F.

    2005-01-01

    Plains-type folds are local, subtle anticlines formed in the thin sedimentary package overlying a shallow, crystalline basement on the craton. They are small in areal extent (usually less than 1-3 km 2 [0.4-1.2 mi2]), and their amplitude increases with depth (usually tens of meters), which is mainly the result of differential compaction of sediments (usually clastic units) over tilted, rigid, basement fault blocks. The development of these structural features by continuous but intermittent movement of the basement fault blocks in the late Paleozoic in the United States mid-continent is substantiated by a record of stratigraphic and sedimentological evidence. The recurrent structural movement, which reflects adjustment to external stresses, is expressed by the change in thickness of stratigraphic units over the crest of the fold compared to the flanks. By plotting the change in thickness for different stratigraphic units of anticlines on different fault blocks, it is possible to determine the timing of movement of the blocks that reflect structural adjustment. These readjustments are confirmed by sedimentological evidence, such as convolute, soft-sediment deformation features and small intraformational faults. The stratigraphic interval change in thickness for numerous structures in the Cherokee, Forest City, and Salina basins and on the Nemaha anticline of the mid-continent United States was determined and compared for location and timing of the adjustments. Most of the adjustment occurred during and after time of deposition of the Permian-Pennsylvanian clastic units, which, in turn, reflect tectonic disturbance in adjacent areas, and the largest amount of movement on the plains-type structures occurred on those nearest and semiparallel to major positive features, such as the Nemaha anticline. Depending on the time of origin and development of plains-type folds, they may control the entrapment and occurrence of oil and gas. Copyright ??2005. The American

  3. Large-scale Distribution of CH4 in the Western North Pacific: Sources and Transport from the Asian Continent

    NASA Technical Reports Server (NTRS)

    Bartlett, Karen B.; Sachse, Glen W.; Slate, Thomas; Harward, Charles; Blake, Donald R.

    2003-01-01

    Methane (CH4) mixing ratios in the northern Pacific Basin were sampled from two aircraft during the TRACE-P mission (Transport and Chemical Evolution over the Pacific) from late February through early April 2001 using a tunable diode laser system. Described in more detail by Jacob et al., the mission was designed to characterize Asian outflow to the Pacific, determine its chemical evolution, and assess changes to the atmosphere resulting from the rapid industrialization and increased energy usage on the Asian continent. The high-resolution, high-precision data set of roughly 13,800 CH4 measurements ranged between 1602 ppbv in stratospherically influenced air and 2149 ppbv in highly polluted air. Overall, CH4 mixing ratios were highly correlated with a variety of other trace gases characteristic of a mix of anthropogenic industrial and combustion sources and were strikingly correlated with ethane (C2H6) in particular. Averages with latitude in the near-surface (0-2 km) show that CH4 was elevated well above background levels north of 15 deg N close to the Asian continent. In the central and eastern Pacific, levels of CH4 were lower as continental inputs were mixed horizontally and vertically during transport. Overall, the correlation between CH4 and other hydrocarbons such as ethane (C2H6), ethyne (C2H2), and propane (C3H8) as well as the urban/industrial tracer perchloroethene (C2Cl4), suggests that for CH4 colocated sources such as landfills, wastewater treatment, and fossil fuel use associated with urban areas dominate regional inputs at this time. Comparisons between measurements made during TRACE-P and those of PEM-West B, flown during roughly the same time of year and under a similar meteorological setting 7 years earlier, suggest that although the TRACE-P CH4 observations are higher, the changes are not significantly greater than the increases seen in background air over this time interval.

  4. Increasing Potential Risk of a Global Aquatic Invader in Europe in Contrast to Other Continents under Future Climate Change

    PubMed Central

    Liu, Xuan; Guo, Zhongwei; Ke, Zunwei; Wang, Supen; Li, Yiming

    2011-01-01

    Background Anthropogenically-induced climate change can alter the current climatic habitat of non-native species and can have complex effects on potentially invasive species. Predictions of the potential distributions of invasive species under climate change will provide critical information for future conservation and management strategies. Aquatic ecosystems are particularly vulnerable to invasive species and climate change, but the effect of climate change on invasive species distributions has been rather neglected, especially for notorious global invaders. Methodology/Principal Findings We used ecological niche models (ENMs) to assess the risks and opportunities that climate change presents for the red swamp crayfish (Procambarus clarkii), which is a worldwide aquatic invasive species. Linking the factors of climate, topography, habitat and human influence, we developed predictive models incorporating both native and non-native distribution data of the crayfish to identify present areas of potential distribution and project the effects of future climate change based on a consensus-forecast approach combining the CCCMA and HADCM3 climate models under two emission scenarios (A2a and B2a) by 2050. The minimum temperature from the coldest month, the human footprint and precipitation of the driest quarter contributed most to the species distribution models. Under both the A2a and B2a scenarios, P. clarkii shifted to higher latitudes in continents of both the northern and southern hemispheres. However, the effect of climate change varied considerately among continents with an expanding potential in Europe and contracting changes in others. Conclusions/Significance Our findings are the first to predict the impact of climate change on the future distribution of a globally invasive aquatic species. We confirmed the complexities of the likely effects of climate change on the potential distribution of globally invasive species, and it is extremely important to develop

  5. An assessment of stressor extent and biological condition in the North American mid-continent great rivers (USA)

    USGS Publications Warehouse

    Angradi, Ted R.; Bolgriend, David W.; Jicha, Terri M.; Pearson, Mark S.; Taylor, Debra L.; Moffett, Mary F.; Blocksom, Karen A.; Walters, David M.; Elonen, Colleen M.; Anderson, Leroy E.; Lazorchak, James M.; Reavie, Euan D.; Kireta, Amy R.; Hill, Brian H.

    2011-01-01

    We assessed the North American mid-continent great rivers (Upper Mississippi, Missouri, and Ohio). We estimated the extent of each river in most- (MDC) or least-disturbed condition (LDC) based on multiple biological response indicators: fish and macroinvertebrate, trophic state based on chlorophyll a, macrophyte cover, and exposure of fish-eating wildlife to toxic contaminants in fish tissue (Hg, total chlordane, total DDT, PCBs). We estimated the extent of stressors on each river including nutrients, suspended solids, sediment toxicity, invasive species, and land use (agriculture and impervious surface). All three rivers had a greater percent of their river length in MDC than in LDC based on fish assemblages. The Upper Mississippi River had the greatest percent of river length with eutrophic status. The Ohio River had the greatest percent of river length with fish with tissue contaminant levels toxic to wildlife. Overall, condition indices based on fish assemblages were more sensitive to stress than macroinvertebrate indices. Compared to the streams in its basin, more of the Upper Mississippi and Missouri Rivers were in MDC for nutrients than the Ohio River. Invasive species (Asian carp and Dreissenid mussels) were less widespread and less abundant on the Missouri River than on the other great rivers. The Ohio River had the most urbanized floodplains (greatest percent impervious surface). The Missouri River had the most floodplain agriculture. The effect of large urban areas on river condition was apparent for several indicators. Ecosystem condition based in fish assemblages, trophic state, and fish tissue contamination was related to land use on the floodplain and at the subcatchment scale. This is the first unbiased bioassessment of the mid-continent great rivers in the United States. The indicators, condition thresholds, results, and recommendations from this program are a starting point for improved future great river assessments.

  6. Early Eocene (c. 50 Ma) collision of the Indian and Asian continents: Constraints from the North Himalayan metamorphic rocks, southeastern Tibet

    NASA Astrophysics Data System (ADS)

    Ding, Huixia; Zhang, Zeming; Dong, Xin; Tian, Zuolin; Xiang, Hua; Mu, Hongchen; Gou, Zhengbin; Shui, Xinfang; Li, Wangchao; Mao, Lingjuan

    2016-02-01

    Despite several decades of investigations, the nature and timing of the India-Asia collision remain debated. In the western Himalaya, the leading edge of the Indian continent was deeply subducted to mantle depths and experienced ultrahigh-pressure metamorphism in the Eocene at c. 50 Ma. In this paper, however, we demonstrate that the North Himalayan metamorphic rocks in the eastern Himalaya underwent Early Eocene (48-45 Ma) medium-pressure (MP) metamorphism due to shallow subduction of the Indian continent beneath southeastern Tibet. The studied garnet-kyanite-staurolite schists occur in the core of the Yardoi gneiss dome, the easternmost North Himalayan Gneiss Dome, and represent the upper structural level of the Higher Himalayan Crystallines (HHC). Petrology and phase equilibria modeling show that these rocks have mineral assemblages of Grt + Pl + Bt + Qz ± Ky ± St ± Ms that were formed under conditions of 7-8 kbar and 630-660 °C. Zircon U-Pb chronology shows that these rocks have peak-metamorphic ages of 48-45 Ma and protracted zircon growth, indicating that the collision between Indian and Asian continents must have occurred at c. 50 Ma in southeastern Tibet. Combining with available data, we suggest that the HHC represents a crustal section of the subducted and subsequently exhumed Indian continent. Due to shallow subduction of the continent during the Eocene, the middle to lower crust of the continent was subducted into depths of 40-60 km and underwent high-pressure (HP) and high-temperature (HT) granulite-facies metamorphism and intense anatexis, whereas the upper crust was buried to shallower depths of 20-30 km and witnessed MP metamorphism and intrusion of leucogranites derived from the lower structural level of the HHC.

  7. Sublatitudinal Isotope Heterogeneity of The Atlantic and Adjacent Continents: A Relation To The Litospheric Plates and Superplums

    NASA Astrophysics Data System (ADS)

    Mironov, Yu. V.; Ryakhovsky, V. M.; Pustovoy, A. A.; Lapidus, I. V.

    Four Sr-Nd-Pb isotope sublatitudinal provinces are chosen in the Atlantic and on ad- jacent continents. They include mid-ocean ridges, oceanic rises and islands, as well as Late Mesozoic - Cenozoic continental rifts and traps. A modified Zindler-Hart "man- tle tetrahedron" (1986) have been used for rock systematics. Its major classification element alongside with known end-members (DM, HIMU, EM1, EM2) is any in- tratetrahedron component F ("focal") (Mironov et al., 2000; Rundquist et al., 2000; Ryakhovsky, 2000). It represents average characteristic of all known intratetrahedron components (FOZO, C, PREMA etc.), updated by methods of multidimensional statis- tics. Northern province includes Mid-Atlantic Ridge from a southern part of Reykjanes ridge up to 24S, numerous islands and rises, located at the same latitudes, Cameroon Line, African and European rifts, Aden and Red sea spreading centres, and also Co- mores in Indian ocean. The main composition dispersion of volcanics from withinplate oceanic and continental structures is determined by mixture of F and HIMU (rarely with admixture EM2). MORB within this area are characterized by stable admixture HIMU. Similar composition have the rocks in Bouvet-Antarctic province, within the limits of which the rises Spiss and Shona, the most southern part of Mid-Atlantic ridge, island Bouvet, an adjacent part of Southwest-Indian Ridge, and also traps and rifts on northern coast of Antarctic Continent are located. The Southern province lies in outlines of known Southern hemisphere DUPAL-anomaly (Hart, 1984). The with- inplate oceanic rocks (Gough, Tristan-da-Kunha, Walvis ridge, Rio Grande Plateau, Discovery) correspond to a mixture F + EM1 (sometimes F + EM1 + EM2) and are similar with traps of Southern America and Africa. Further to east this province is traced on islands and mid-ocean ridges in Indian ocean. MORB of Southern Atlantic and Indian ocean are enriched EM1. The Arctic province includes spreading ridges of

  8. Reduction of Risk in Exploration and Prospect Generation through a Multidisciplinary Basin-Analysis Program in the South-Central Mid-Continent Region

    SciTech Connect

    Banerjee, S.; Barker, C.; Fite, J.; George, S.; Guo, Genliang; Johnson, W.; Jordan, J., Szpakiewicz, M.; Person, M.; Reeves, T.K.; Safley, E.; Swenson, J.B.; Volk, L.; and Erickson, R.

    1999-04-02

    This report will discuss a series of regional studies that were undertaken within the South-Central Mid-Continent region of the U.S. Coverage is also provided about a series of innovative techniques that were used for this assessment.

  9. Annotated Bibliography of Children's Literature Resources on War, Terrorism, and Disaster since 1945: By Continents/Countries for Grades K-8

    ERIC Educational Resources Information Center

    Gangi, Jane M.

    2009-01-01

    This article presents an annotated bibliography of children's literature resources on war, terrorism, and disaster since 1945. This annotated bibliography focuses on grades K-8 from different continents/countries, including (1) Africa; (2) Asia; (3) The Caribbean; (4) Central and South America; (5) Europe; and (6) The Middle East.

  10. Crustal Structure in the area of the North American Mid-Continent Rift System from P-wave Receiver Functions

    NASA Astrophysics Data System (ADS)

    Zhang, H.; van der Lee, S.; Wolin, E.; Bollmann, T. A.; Revenaugh, J.; Wiens, D. A.; Wysession, M. E.; Aleqabi, G. I.; Frederiksen, A. W.; Darbyshire, F. A.; Stein, S. A.; Jurdy, D. M.

    2015-12-01

    The Mid-continent Geophysical Anomaly (MGA) represents the largest gravity anomaly in the North American continental interior, its strongest portion stretching from Iowa to Lake Superior, and is the direct result of 1.1 Ga deposition and uplift of volcanic rocks in the Mid-continent Rift System (MRS). The Superior Province Rifting Earthscope Experiment (SPREE) collected broadband seismic data around this prominent portion of the MGA for 2.5 years from 82 seismic stations, simultaneously with about 30 Transportable Array (TA) stations in the region. To image crustal structure around the MGA, we analyzed the P-wave trains of 119 teleseismic earthquakes at these stations using the time-domain iterative-deconvolution method of Ligorria and Ammon (1999), the waveform-fitting method of Van der Meijde et al. (2003), and the H-κ stacking method of Zhu and
Kanamori (2000). Our aim was to resolve intra-crustal layering and Moho characteristics. Despite considerable noise related to station installation constraints, we find that outside of the MGA, the Moho is sharp and relatively flat, both beneath the Archean Superior Province as well as beneath the Proterozoic terranes to its south. This Moho produces consistent P to S converted phases in the analyzed receiver functions. Receiver functions show much more complexity along the MGA, where P to S converted phases from the Moho are much weaker and more variable with azimuth and epicentral distance. Similar results have been found in Iowa by French et al. (2009). For many stations along the MGA, multiple weak S phases arrive around the time expected for the Moho-converted phase. In addition, strong P-to-S converted phases are observed from the base of shallow sedimentary layers. The base of the sedimentary layer is fairly shallow outside of the MGA, thickens near the flanks where gravity anomalies are low and shallows again in the center where the gravity peaks. We conclude that the Moho is not a strong feature of the MRS

  11. Constraints on the Mid-Continent Deformation Gravity Gradient Determined from Co-located GPS and Absolute Gravity Observations

    NASA Astrophysics Data System (ADS)

    James, T. S.; Mazzotti, S.; Mazzotti, S.; Lambert, A.

    2001-12-01

    The deformation gravity gradient (DGG) is the ratio of the time rate of change of surface gravity to vertical crustal velocity. Different processes generate different theoretical predictions of the DGG. Consequently, observational constraints on the DGG are necessary to link crustal uplift observations to satellite-derived observations of the time rate of change of the Earth's gravitational field, which will be generated by upcoming satellite missions such as GRACE. Larson and van Dam (2000) have compared secular gravity trends from 4 sites in interior North America to crustal uplift rates obtained from global point-positioning analyses of GPS observations, and found they agree, assuming a nominal DGG value appropriate to postglacial rebound of -0.15 μ Gal/mm (Wahr et al., 1995). Here we revisit and extend their analysis in order to determine the observational constraints on the DGG in mid-continent North America. We use recently published gravity rates derived from significantly more absolute gravity observations and a different GPS analysis scheme. Lambert et al. (2001) have published secular gravity rates for 7 sites in mid-continent North America, using all available absolute gravity observations and allowing for instrumental offsets. The sites, chosen to sample postglacial rebound, lie on a transect from Churchill, Manitoba, located on Hudson Bay, to North Liberty, Iowa. Four of these sites (Churchill, Flin Flon, Lac du Bonnet, and North Liberty) also feature a nearby GPS station. The GPS observations were analyzed using double differencing with Bernese 4.2, yielding 5 year time series for vertical position. The daily repeatabilities of 5 to 9 mm compare well to the weekly repeatabilities of 7-8 mm reported by Larson and van Dam (2000). A comparison of the vertical rates derived from these time series to the secular solid-surface gravity trends finds a DGG of -0.14 +/- 0.06 μ Gal/mm. This value is in good agreement with model predictions for postglacial

  12. Continent-Wide Decoupling of Y-Chromosomal Genetic Variation from Language and Geography in Native South Americans

    PubMed Central

    Gusmão, Leonor; Gomes, Veronica; González, Miguel; Corach, Daniel; Sala, Andrea; Alechine, Evguenia; Palha, Teresinha; Santos, Ney; Ribeiro-dos-Santos, Andrea; Geppert, Maria; Willuweit, Sascha; Nagy, Marion; Zweynert, Sarah; Baeta, Miriam; Núñez, Carolina; Martínez-Jarreta, Begoña; González-Andrade, Fabricio; Fagundes de Carvalho, Elizeu; da Silva, Dayse Aparecida; Builes, Juan José; Turbón, Daniel; Lopez Parra, Ana Maria; Arroyo-Pardo, Eduardo; Toscanini, Ulises; Borjas, Lisbeth; Barletta, Claudia; Ewart, Elizabeth; Santos, Sidney; Krawczak, Michael

    2013-01-01

    Numerous studies of human populations in Europe and Asia have revealed a concordance between their extant genetic structure and the prevailing regional pattern of geography and language. For native South Americans, however, such evidence has been lacking so far. Therefore, we examined the relationship between Y-chromosomal genotype on the one hand, and male geographic origin and linguistic affiliation on the other, in the largest study of South American natives to date in terms of sampled individuals and populations. A total of 1,011 individuals, representing 50 tribal populations from 81 settlements, were genotyped for up to 17 short tandem repeat (STR) markers and 16 single nucleotide polymorphisms (Y-SNPs), the latter resolving phylogenetic lineages Q and C. Virtually no structure became apparent for the extant Y-chromosomal genetic variation of South American males that could sensibly be related to their inter-tribal geographic and linguistic relationships. This continent-wide decoupling is consistent with a rapid peopling of the continent followed by long periods of isolation in small groups. Furthermore, for the first time, we identified a distinct geographical cluster of Y-SNP lineages C-M217 (C3*) in South America. Such haplotypes are virtually absent from North and Central America, but occur at high frequency in Asia. Together with the locally confined Y-STR autocorrelation observed in our study as a whole, the available data therefore suggest a late introduction of C3* into South America no more than 6,000 years ago, perhaps via coastal or trans-Pacific routes. Extensive simulations revealed that the observed lack of haplogroup C3* among extant North and Central American natives is only compatible with low levels of migration between the ancestor populations of C3* carriers and non-carriers. In summary, our data highlight the fact that a pronounced correlation between genetic and geographic/cultural structure can only be expected under very specific

  13. Potential for producing oil and gas from Woodford Shale (Devonian-Mississippian) in the southern Mid-Continent, USA

    SciTech Connect

    Comer, J.B. )

    1991-03-01

    Woodford Shale is a prolific oil source rock throughout the southern Mid-Continent of the US. Extrapolation of thickness and organic geochemical data based on the analysis of 614 samples from the region indicate that on the order of 100 {times} 10{sup 9} bbl of oil (300 {times} 10{sup 12} ft {sup 3} of natural gas equivalent). Tapping this resource is most feasible in areas where the Woodford subcrop contains competent lithofacies (e.g., chert, sandstone, siltstone, dolostone) and is high fractured. Horizontal drilling may provide the optimum exploitation technique. Areas with the greatest potential and the most prospective lithologies include (1) the Nemaha uplift (chert, sandstone, dolostone), (2) Marietta-Ardmore basin (chert), (3) southern flank of the Anadarko basin along the Wichita Mountain uplift (chert), (4) frontal zone of the Ouachita tectonic belt in Oklahoma (chert), and (5) the Central Basin platform in west Texas and New Mexico (chert and siltstone). In virtually all of these areas the Woodford is in the oil or gas window. Thus, fracture porosity would be continuously fed by hydrocarbons generated in the enclosing source rocks. Reservoir systems such as these have typically produced at low to moderate flow rates for many decades.

  14. Potential for producing oil and gas from the Woodford Shale (Devonian-Mississippian) in the southern mid-continent, USA

    SciTech Connect

    Comer, J.B. )

    1992-04-01

    The Woodford Shale is a prolific oil source rock throughout the southern mid-continent of the United States. Extrapolation of thickness and organic geochemical data based on the analysis of 614 samples from the region indicate that on the order of 100 {times} 10{sup 9} bbl of oil (300 {times} 10{sup 12} ft{sup 3} of natural gas equivalent) reside in the Woodford in Oklahoma and northwestern Arkansas. The Woodford in west Texas and southeastern New Mexico contains on the order of 80 {times} 10{sup 9} bbl of oil (240 {times} 10{sup 12} ft{sup 3} of natural gas equivalent). Tapping this resource is most feasible in areas where the Woodford subcrop contains competent lithofacies (e.g., chert, sandstone, siltstone, dolostone) and is highly fractured. Horizontal drilling may provide the optimum exploitation technique. Areas with the greatest potential and the most prospective lithologies include (1) the Nemaha uplift (chert, sandstone, dolostone), (2) Marietta-Ardmore basin (chert), (3) southern flank of the Anadarko basin along the Wichita Mountain uplift (chert), (4) frontal zone of the Ouachita tectonic belt in Oklahoma (chert), and (5) the Central Basin platform in west Texas and New Mexico (chert and siltstone). In virtually all of these areas, the Woodford is in the oil or gas window. Thus, fracture porosity would be continuously fed by hydrocarbons generated in the enclosing source rocks. Reservoir systems such as these typically have produced at low to moderate flow rates for many decades.

  15. Death by sex in an Australian icon: a continent-wide survey reveals extensive hybridization between dingoes and domestic dogs.

    PubMed

    Stephens, Danielle; Wilton, Alan N; Fleming, Peter J S; Berry, Oliver

    2015-11-01

    Hybridization between domesticated animals and their wild counterparts can disrupt adaptive gene combinations, reduce genetic diversity, extinguish wild populations and change ecosystem function. The dingo is a free-ranging dog that is an iconic apex predator and distributed throughout most of mainland Australia. Dingoes readily hybridize with domestic dogs, and in many Australian jurisdictions, distinct management strategies are dictated by hybrid status. Yet, the magnitude and spatial extent of domestic dog-dingo hybridization is poorly characterized. To address this, we performed a continent-wide analysis of hybridization throughout Australia based on 24 locus microsatellite DNA genotypes from 3637 free-ranging dogs. Although 46% of all free-ranging dogs were classified as pure dingoes, all regions exhibited some hybridization, and the magnitude varied substantially. The southeast of Australia was highly admixed, with 99% of animals being hybrids or feral domestic dogs, whereas only 13% of the animals from remote central Australia were hybrids. Almost all free-ranging dogs had some dingo ancestry, indicating that domestic dogs could have poor survivorship in nonurban Australian environments. Overall, wild pure dingoes remain the dominant predator over most of Australia, but the speed and extent to which hybridization has occurred in the approximately 220 years since the first introduction of domestic dogs indicate that the process may soon threaten the persistence of pure dingoes. PMID:26514639

  16. Afferent nipple valve malfunction caused by anchoring collar: an unexpected late complication of the Kock continent ileal reservoir.

    PubMed

    Arai, Y; Okada, Y; Matsuda, T; Hida, S; Takeuchi, H; Kihara, Y; Yoshida, O

    1991-01-01

    In the construction of a Kock continent ileal reservoir for urinary diversion, significantly high rates of late postoperative complications regarding nipple valves, the efferent limb in particular, have been reported. There are only a few reports on afferent nipple valve malfunction. A total of 42 patients who underwent a Kock pouch operation and were observed for more than 12 months (mean 38 months) was evaluated in terms of afferent nipple valve malfunction. Late afferent nipple valve complications were observed in 10 of the 42 patients (24%). These complications included erosion of the polyester fiber fabric used as a collar (5 patients), stenosis of the afferent limb (2) and obstruction of the afferent nipple by a mucous plug or fungus ball (3). The latter 2 complications were due to mechanical or dynamic obstruction of urine flow caused by a nonabsorbable collar. None of the 10 patients had problems with efferent nipple valve function. Our results suggest that the peristaltic direction of the intestine and the use of nonabsorbable material as a collar are primarily responsible for the late afferent nipple valve complications. Further modifications are needed to produce a stable nipple valve. Otherwise, simpler and more reliable alternative techniques of antireflux anastomosis should be considered. PMID:1984094

  17. Geologic Evolution of North America: Geologic features suggest that the continent has grown and differentiated through geologic time.

    PubMed

    Engel, A E

    1963-04-12

    The oldest decipherable rock complexes within continents (more than 2.5 billion years old) are largely basaltic volcanics and graywacke. Recent and modern analogs are the island arcs formed along and adjacent to the unstable interface of continental and oceanic crusts. The major interfacial reactions (orogenies) incorporate pre-existing sial, oceanic crust, and mantle into crust of a more continental type. Incipient stages of continental evolution, more than 3 billion years ago, remain obscure. They may involve either a cataclysmic granite-forming event or a succession of volcanic-sedimentary and granite-forming cycles. Intermediate and recent stages of continental evolution, as indicated by data for North America, involve accretion of numerous crustal interfaces with fragments of adjacent continental crust and their partial melting, reinjection, elevation, unroofing, and stabilization. Areas of relict provinces defined by ages of granites suggest that continental growth is approximately linear. But the advanced differentiation found in many provinces and the known overlaps permit wide deviation from linearity in the direction of a more explosive early or intermediate growth. PMID:17819825

  18. Evaluation of regional-scale hydrological models using multiple criteria for 12 large river basins on all continents

    NASA Astrophysics Data System (ADS)

    Huang, Shaochun; Krysanova, Valentina; Hattermann, Fred; Vetter, Tobias; Flörke, Martina; Samaniego, Luis; Arheimer, Berit; Yang, Tao; van Griensven, Ann; Su, Buda; Gelfan, Alexander; Breuer, Lutz; Haberlandt, Uwe

    2016-04-01

    A good performance of hydrological impact models under historical climate and land use conditions is a prerequisite for reliable projections under climate change. The evaluation of nine regional-scale hydrological models considering monthly river discharge, long-term average seasonal dynamics and extremes was performed in the framework of the ISI-MIP project for 12 large river basins on all continents. The modelling tools include: ECOMAG, HBV, HYMOD, HYPE, mHM, SWAT, SWIM, VIC and WaterGAP3. These models were evaluated for the following basins: the Rhine and Tagus in Europe, the Niger and Blue Nile in Africa, the Ganges, Lena, Upper Yellow and Upper Yangtze in Asia, the Upper Mississippi, MacKenzie and Upper Amazon in America, and Darling in Australia. The model calibration and validation was done using WATCH climate data for all cases. The model outputs were evaluated using twelve statistical criteria to assess the fidelity of model simulations for monthly discharge, seasonal dynamics, flow duration curves, extreme floods and low flow. The reproduction of monthly discharge and seasonal dynamics was successful in all basins except the Darling, and the high flows and flood characteristics were also captured satisfactory in most cases. However, the criteria for low flow were below the thresholds in many cases. An overview of this collaborative experiment and main results on model evaluation will be presented.

  19. Effect of combined application insulin and insulin detemir on continous glucose monitor in children with type 1 diabetes mellitus

    PubMed Central

    Chen, Xiao-Yun; Dong, Qing; Li, Gui-Mei

    2015-01-01

    Insulin detemir is a soluble long-acting human insulin analogue at neutral pH with a unique mechanism of action, which could strengthen the effects of insulin. This study aims to explore the effects of insulin combined with insulin detemir on the continous glucose in children with type 1 diabetes mellitus. In this study, 150 patients with type 1 diabetes enrolled were included and randomly divided into 3 groups: insulin group (group A), insulin detemir group (group B) and insulin combined with insulin detemir group (group C). Each subject underwent 72 h of continuous glucose monitoring (CGM). MAGE, HbA1c and Noctumal Hypoglycemia levels were examined by using the ELISA kits. The body weight changes were also detected in this study. The results indicated that the information including age, body weight, disease duration and glucose level and HbA1c percentage on the start time point among three groups indicated no statistical differences. Insulin combined with insulin detemir decrease MAGE and HbA1c level in Group C compared to Group A and Group A (P < 0.05). Insulin combined with insulin detemir decreas noctumal hypoglycemia levels and body weight changes (P < 0.05). In conclusion, this study confirmed efficacy of insulin detemir by demonstrating non-inferiority of insulin detemir compared with insulin with respect to HbA1c, with an improved safety profile including significantly fewer hypoglycaemic episodes and less undesirable weight gain in children. PMID:26064343

  20. Wing trait-inversion associations in Drosophila subobscura can be generalized within continents, but may change through time.

    PubMed

    Simões, P; Fragata, I; Lopes-Cunha, M; Lima, M; Kellen, B; Bárbaro, M; Santos, M; Matos, M

    2015-12-01

    Clinal variation is one of the most emblematic examples of the action of natural selection at a wide geographical range. In Drosophila subobscura, parallel clines in body size and inversions, but not in wing shape, were found in Europe and South and North America. Previous work has shown that a bottleneck effect might be largely responsible for differences in wing trait-inversion association between one European and one South American population. One question still unaddressed is whether the associations found before are present across other populations of the European and South American clines. Another open question is whether evolutionary dynamics in a new environment can lead to relevant changes in wing traits-inversion association. To analyse geographical variation in these associations, we characterized three recently laboratory founded D. subobscura populations from both the European and South American latitudinal clines. To address temporal variation, we also characterized the association at a later generation in the European populations. We found that wing size and shape associations can be generalized across populations of the same continent, but may change through time for wing size. The observed temporal changes are probably due to changes in the genetic content of inversions, derived from adaptation to the new, laboratory environment. Finally, we show that it is not possible to predict clinal variation from intrapopulation associations. All in all this suggests that, at least in the present, wing traits-inversion associations are not responsible for the maintenance of the latitudinal clines in wing shape and size. PMID:26302686

  1. Continent-wide association of H5N1 outbreaks in wild and domestic birds in Europe

    PubMed Central

    Williams, Richard A. J.; Xiao, Xiang-Ming; Peterson, A. Townsend

    2016-01-01

    The highly pathogenic avian influenza strain H5N1 was first detected in Europe in 2005, and has since been documented continent-wide in wild birds and poultry. However, the relative roles of each host group in transmission remain contentious. Using recently developed tools for analysis of ecological niches and geographic distributions of species, we compared ecological niche requirements for H5N1 between paired host groups (poultry versus wild birds, Anseriformes versus Falconiformes, swans versus non-swan Anseriformes). If environmental signals of different host groups are significantly different, the groups are likely to be involved in distinct transmission cycles. In contrast, models for which similarity cannot be rejected imply no unique ecological niches and no potential linkage of transmission cycles. In 24 similarity tests, we found significant similarity (13/24) or no significant differences (9/24). Although 2 of the 24 analyses showed significant differences, neither was unequivocal, so we conclude an overall signal of niche similarity among groups. We thus could not document distinct ecological niches for H5N1 occurrences in different host groups and conclude that the transmission cycles are broadly interwoven. PMID:21590675

  2. Impact of Different Body Positions on Bioelectrical Activity of the Pelvic Floor Muscles in Nulliparous Continent Women

    PubMed Central

    Chmielewska, Daria; Stania, Magdalena; Sobota, Grzegorz; Kwaśna, Krystyna; Błaszczak, Edward; Taradaj, Jakub; Juras, Grzegorz

    2015-01-01

    We examined pelvic floor muscles (PFM) activity (%MVC) in twenty nulliparous women by body position during exercise as well as the activation of abdominal muscles and the gluteus maximus during voluntary contractions of the PFMs. Pelvic floor muscle activity was recorded using a vaginal probe during five experimental trials. Activation of transversus abdominis, rectus abdominis, and gluteus maximus during voluntary PFM contractions was also assessed. Significant differences in mean normalized amplitudes of baseline PFM activity were revealed between standing and lying (P < 0.00024) and lying and ball-sitting positions (P < 0.0053). Average peak, average time before peak, and average time after peak did not differ significantly during the voluntary contractions of the PFMs. Baseline PFM activity seemed to depend on the body position and was the highest in standing. Pelvic floor muscles activity during voluntary contractions did not differ by position in continent women. Statistically significant differences between the supine lying and sitting positions were only observed during a sustained 60-second contraction of the PFMs. PMID:25793212

  3. Reconciliation of Carbon Dioxide Flux Estimates from Atmospheric Inversions and Inventories in the Mid-Continent Intensive

    NASA Astrophysics Data System (ADS)

    Breidt, F. J.; Cooley, D. S.; Thurier, Q.; Wang, Y.; Schuh, A. E.; Denning, A.; Davis, K. J.; West, T. O.; Ogle, S. M.

    2009-12-01

    Atmospheric inversions and inventories provide two distinct data sources for describing regional carbon budgets in the Mid-Continent Intensive (MCI) study of the North American Carbon Program (NACP). Inversions rely on temporally rich CO2 concentration measurements to infer fluxes between the terrestrial surface and atmosphere. Since towers from which concentration measurements are obtained are sparsely distributed on the landscape, inversion data tend to be temporally rich and spatially poor. Inventories are typically conducted using models for which the inputs are driving variables that influence uptake and release of CO2 from the terrestrial surface, and the outputs are predicted changes in C pools, or CO2 fluxes directly. In contrast to inversions, the inventory data tend to be spatially rich and temporally poor. A statistical methodology based on a state-space model and the Kalman recursions is proposed to combine the inversion and inventory data for optimal estimation of CO2 fluxes. The methodology trades off the strengths and weaknesses of the two data streams. This synthesis activity provides the most rigorous estimates of CO2 flux for the MCI, along with estimated uncertainties. In particular, it identifies portions of the region and time series, as well as sources and C pools, with the largest uncertainties.

  4. Comparison of Regional Carbon Dioxide Fluxes from Atmospheric Inversions and Inventories in the Mid-Continent Intensive

    NASA Astrophysics Data System (ADS)

    Ogle, S. M.; Cooley, D. S.; Schuh, A. E.; Denning, A.; Davis, K. J.; West, T. O.; Breidt, F. J.

    2009-12-01

    Atmospheric inversions and inventories represent two lines of evidence on the carbon budget of regions. Inversions rely on repeated CO2 concentration measurements to infer fluxes between the terrestrial surface and atmosphere. Inventories are typically conducted using models to predict changes in C pools, or CO2 fluxes directly, based on various driving variables influencing uptake and release of CO2 from the terrestrial surface. Both of the approaches have their strengths and weaknesses, and one of the key objectives of the Mid-Continent Intensive (MCI) for the North American Carbon Program (NACP) is to reconcile differences in estimates between these approaches, to the extent possible. An exploratory approach has been undertaken to compare inventory and inversions using graphical tools, testing for spatial and temporal autocorrelations, and a regression analysis where the differences between the inventories and inversions are regressed against both inventory estimates and land-use characteristics. Results from a pre-campaign time period (2000-05) suggest limited agreement between the inversions and inventory results that is due to a lack of atmospheric observations in the MCI region. However, sampling density is much greater during the campaign years (2007-08), and inventory and inversion data are more comparable given the improved observational constraint on the high resolution inversions. Overall, this synthesis activity is improving diagnosis of regional carbon fluxes, which is a key objective of the NACP.

  5. A study on crustal shear wave splitting in the western part of the Banda arc-continent collision

    NASA Astrophysics Data System (ADS)

    Syuhada, Hananto, Nugroho D.; Puspito, Nanang T.; Anggono, Titi; Yudistira, Tedi

    2016-03-01

    We analyzed shear wave splitting parameters from local shallow (< 30 km) earthquakes recorded at six seismic stations in the western part of the Banda arc-continent collision. We determined fast polarization and delay time for 195 event-stations pairs calculated from good signal-to-noise ratio waveforms. We observed that there is evidence for shear wave splitting at all stations with dominant fast polarization directions oriented about NE-SW, which are parallel to the collision direction of the Australian plate. However, minor fast polarization directions are oriented around NW-SE being perpendicular to the strike of Timor through. Furthermore, the changes in fast azimuths with the earthquake-station back azimuth suggest that the crustal anisotropy in the study area is not uniform. Splitting delay times are within the range of 0.05 s to 0.8 s, with a mean value of 0.29±0.18 s. Major seismic stations exhibit a weak tendency increasing of delay times with increasing hypocentral distance suggesting the main anisotropy contribution of the shallow crust. In addition, these variations in fast azimuths and delay times indicate that the crustal anisotropy in this region might not only be caused by extensive dilatancy anisotropy (EDA), but also by heterogeneity shallow structure such as the presence of foliations in the rock fabric and the fracture zones associated with active faults.

  6. Heat flow patterns of the North American continent: A discussion of the DNAG Geothermal Map of North America

    SciTech Connect

    Blackwell, David D.; Steele, John L.; Carter, Larry C.

    1990-01-01

    The large and small-scale geothermal features of the North American continent and surrounding ocean areas illustrated on the new 1:5,000,000 DNAG Geothermal Map of North America are summarized. Sources for the data included on the map are given. The types of data included are heat flow sites coded by value, contours of heat flow with a color fill, areas of major groundwater effects on regional heat flow, the top-of-geopressure in the Gulf Coast region, temperature on the Dakota aquifer in the midcontinent, location of major hot springs and geothermal systems, and major center of Quaternary and Holocene volcanism. The large scale heat flow pattern that is well known for the conterminous United States and Canada of normal heat flow east of the Cordillera and generally high heat flow west of the front of the Cordillera dominates the continental portion of the map. However, details of the heat flow variations are also seen and are discussed briefly in this and the accompanying papers.

  7. Mid-continent Magnetoseismic Chain (McMAC): A Ground-based Magnetometer Chain for Magnetospheric Sounding

    NASA Astrophysics Data System (ADS)

    Chi, P. J.; Engebretson, M. J.; Moldwin, M. B.; Russell, C. T.; Mann, I. R.; Samson, J. C.; Lopez, R. E.; Cruz-Abeyro, J. A.; Yumoto, K.; Lee, D.

    2004-05-01

    The Mid-continent Magnetoseismic Chain (McMaC) is a National Science Foundation (NSF) project that conducts research in magnetospheric sounding using ground magnetic field observations. We refer to the methodology used in this research as ``magneto-seismology,'' reflecting its similarity to terrestrial seismology and helioseismology. The magnetoseismic research consists of two parts: the normal mode analysis that deduces the plasma density along a field line from its resonant frequencies, and the travel-time analysis that infers the density distribution in an extended region by timing the arrival of impulsive signals at multiple locations. To provide necessary data for employing magnetoseismic methods, 9 new magnetic stations will be installed in the United States and Mexico roughly along the 330° magnetic longitude meridian. These new stations will be equipped with highly sensitive fluxgate magnetometers synchronized by GPS signals. The McMAC stations and the ``Fort Churchill Line'' of the CANOPUS will be on the same meridian, and together they form a long north-south chain of magnetometers whose L-values range from 1.3 to 11.7. A database of the mass density of magnetospheric plasma derived from magnetoseismic methods will be established to investigate magnetospheric dynamics under different solar wind and ionospheric conditions.

  8. Emergence of the continents

    NASA Technical Reports Server (NTRS)

    Frey, H.

    1978-01-01

    If early degassing of the Earth produced a global ocean several km deep overlying a global sialic crust, then late heavy bombardment of that crust by basin forming impacting bodies would have produced topography such that by 4 billion years ago dry continential landmasses would stand above sea level. From extrapolation of lunar crater statistics, at least 50% of an original global crust on the earth would have been converted into basins averaging 4 km deep after isostatic adjustment. These basins formed the sink into which such a global ocean would drain. If the ocean was initially 2 km deep, then approximately 50% of the early Earth would have stood above sea level when the late heavy bombardment came to a close.

  9. OxyContin

    MedlinePlus

    ... Contact Get Information Drug Guide A Focus on Heroin & Opioids Breaking Points: Teens & Stress Parent Toolkit The ... medication, causing a rush of euphoria similar to heroin. What are its short-term effects? The most ...

  10. Penile vibratory stimulation in the recovery of urinary continence and erectile function after nerve-sparing radical prostatectomy: a randomized, controlled trial

    PubMed Central

    Fode, Mikkel; Borre, Michael; Ohl, Dana A; Lichtbach, Jonas; Sønksen, Jens

    2014-01-01

    Objective To examine the effect of penile vibratory stimulation (PVS) in the preservation and restoration of erectile function and urinary continence in conjunction with nerve-sparing radical prostatectomy (RP). Patients and Methods The present study was conducted between July 2010 and March 2013 as a randomized prospective trial at two university hospitals. Eligible participants were continent men with an International Index of Erectile Function-5 (IIEF-5) score of at least 18, scheduled to undergo nerve-sparing RP. Patients were randomized to a PVS group or a control group. Patients in the PVS group were instructed in using a PVS device (FERTI CARE® vibrator). Stimulation was performed at the frenulum once daily by the patients in their own homes for at least 1 week before surgery. After catheter removal, daily PVS was re-initiated for a period of 6 weeks. Participants were evaluated at 3, 6 and 12 months after surgery with the IIEF-5 questionnaire and questions regarding urinary bother. Patients using up to one pad daily for security reasons only were considered continent. The study was registered at http://clinicaltrials.gov/ (NCT01067261). Results Data from 68 patients were available for analyses (30 patients randomized to PVS and 38 patients randomized to the control group). The IIEF-5 score was highest in the PVS group at all time points after surgery with a median score of 18 vs 7.5 in the control group at 12 months (P = 0.09), but the difference only reached borderline significance. At 12 months, 16/30 (53%) patients in the PVS group had reached an IIEF-5 score of at least 18, while this was the case for 12/38 (32%) patients in the control group (P = 0.07). There were no significant differences in the proportions of continent patients between groups at 3, 6 or 12 months. At 12 months 90% of the PVS patients were continent, while 94.7% of the control patients were continent (P = 0.46). Conclusion The present study did not document a significant effect of

  11. Remnants of an Ancient Ocean-Continent Transition Exposed in the Alps: A Window for Understanding Break-up Processes

    NASA Astrophysics Data System (ADS)

    Manatschal, G.

    2005-05-01

    In the last two decades, remnants of an ancient Ocean-Continent Transition (OCT) of the Alpine Tethys ocean have been mapped in the Alps in SE Switzerland. The most prominent structure within the reconstructed OCT is a detachment system that can be traced from the thinned continental crust, across a Zone of Exhumed Continental Mantle (ZECM) towards oceanic crust. The detachment system is formed by at least two corrugated detachment faults that are overlain by extensional allochthons, tectono-sedimentary breccias and syn-and post-rift sediments. In the ZECM, basaltic magmas grade from T- to N-MORB oceanwards. Near the continental edge they form isolated volcanic bodies emplaced directly onto exhumed mantle whereas further oceanwards they are more voluminous and associated with syn-magmatic high-angle normal faults. In the OCT, lower crustal rocks are rare and where present related to Permian underplated gabbros preserving primary contacts to mantle rocks. In the ZECM, the mantle rocks change from pyroxenite-rich spinel peridotites close to the continent to pyroxenite-poor peridotites impregnated and intruded by asthenospheric melts further oceanwards. Across the whole OCT, the detachment system can be mapped as a damage zone, up to hundred meters thick, with a core zone formed by gouges. The fault rocks record a complex fluid and reaction assisted retrograde deformation history. Maximum temperatures at which the detachment faults were active are 300C in crustal rocks and 600C in mantle rocks. Enrichment of chromium and nickel along the detachment fault in the continental crust may result from fluids derived from a serpentinizing mantle underlying the extending continental crust. High-temperature granulite facies mylonites are found in the lower crustal and mantle rocks, however, their relation to the detachment is not yet fully understood. In the syn-extensional gabbros microstructures reveal a deformation history ranging from syn-magmatic to seafloor conditions

  12. Carbon isotope variation in mid-continent Ordovician-type oils: relationship to a major middle Ordovician carbon isotope shift

    SciTech Connect

    Hatch, J.R.; Jacobson, S.R.; Witzke, B.J.; Anders, D.E.; Watney, W.L.; Newell, K.D.

    1985-05-01

    Detailed organic geochemical comparisons of Mid-Continent Ordovician oils with extracts of potential source rocks show that in the Forest City basin of northeastern Kansas and southeastern Nebraska, oil source rocks are Middle Ordovician shales of the Simpson Group. For the Keota Dome field, Washington County, Iowa, the oil source rock is the Middle Ordovician Glenwood Shale Member of the Platteville Formation. Analyses of saturated and aromatic hydrocarbon fractions of Ordovician-type oils from the Forest City basin, Keota Dome field, and the Michigan basin show that sigma TC of the two fractions are similar and that sigma T varies over a considerable range, from -32.5 per mil to -25.5 per mil (PDB). This large range in sigma TC reflects a major shift in the carbon isotope composition of organic matter during the Middle Ordovician. This shift is shown in a 62.5-ft (19 m) interval of core from the Decorah and Platteville Formations in the E.M. Greene 1 well in Washington County, Iowa, where organic carbon sigma TC changes regularly upward from -32.2 per mil to -22.7 per mil (PDB). The change in organic carbon sigma TC in this core is not related to variations in amount (0.13-41.4% TOC) or type (hydrogen index = 69 to 1000 mg HC/g TOC) of the marginally mature (T/sub max/ = 440 +/- 5C) organic matter. Ordovician-type oils in both the Forest City and Michigan basins show variable sigma TC, suggesting that the sigma TC shift displayed in the Middle Ordovician rocks of southeastern Iowa is a regional and possibly a global effect, related to changes in the sigma TC of the ocean-atmosphere carbon reservoir. Isotopic analyses of coexisting carbonate minerals support this interpretation.

  13. Heat-flow and hydrothermal circulation at the ocean-continent transition of the eastern gulf of Aden

    NASA Astrophysics Data System (ADS)

    Lucazeau, Francis; Leroy, Sylvie; Rolandone, Frédérique; d'Acremont, Elia; Watremez, Louise; Bonneville, Alain; Goutorbe, Bruno; Düsünur, Doga

    2010-07-01

    In order to investigate the importance of fluid circulation associated with the formation of ocean-continent transitions (OCT), we examine 162 new heat-flow (HF) measurements in the eastern Gulf of Aden, obtained at close locations along eight seismic profiles and with multi-beam bathymetry. The average HF values in the OCT and in the oceanic domain (~ 18 m.y.) are very close to the predictions of cooling models, showing that the overall importance of fluids remains small at the present time compared to oceanic ridge flanks of the same age. However, local HF anomalies are observed, although not systematically, in the vicinity of the unsedimented basement and are interpreted by the thermal effect of meteoric fluids flowing laterally. We propose a possible interpretation of hydrothermal paths based on the shape of HF anomalies and on the surface morphology: fluids can circulate either along-dip or along-strike, but are apparently focussed in narrow "pipes". In several locations in the OCT, there is no detectable HF anomaly while the seismic velocity structure suggests serpentinization and therefore past circulation. We relate the existence of the present day fluid circulation in the eastern Gulf of Aden to the presence of unsedimented basement and to the local extensional stress in the vicinity of the Socotra-Hadbeen fault zone. At the scale of rifted-margins, fluid circulation is probably not as important as in the oceanic domain because it can be inhibited rapidly with high sedimentation rates, serpentinization and stress release after the break-up.

  14. Phylogeography across a continent: the evolutionary and demographic history of the North American racer (Serpentes: Colubridae: Coluber constrictor).

    PubMed

    Burbrink, Frank T; Fontanella, Frank; Alexander Pyron, R; Guiher, Timothy J; Jimenez, Cynthia

    2008-04-01

    Most phylogeographic studies examine organisms that do not have transcontinental distributions and therefore the genetic and temporal effects of barriers across an entire continent cannot be assessed with respect to a single species. We examined the phylogeographic structure, lineage age, and historical demography using sequences from the mtDNA cytochrome b gene of the widespread North American racer (Coluber constrictor), one of the few abundant transcontinental snakes that occurs throughout many diverse biomes. Our results indicate that this complex is comprised of six lineages differing greatly in geographic extent, with the largest (a central US clade) being approximately 26 times greater than the smallest (a lineage restricted to the Florida Panhandle and nearby portions of adjacent States). Most of the six lineages appear to be separated at previously identified genetic barriers for several vertebrates with similar ranges. Lineage diversification in this species began in the late Miocene, separating populations in the Florida Peninsula from the remainder of the US. Diversification of lineages continued throughout the Pliocene and early Pleistocene. Four of the six lineages occur east of the Mississippi River, with only two distinctly young ( approximately 1.5 mya) lineages found west of the Mississippi River (one occurs west of Continental Divide). All methods of demographic inference, including the mismatch distribution, Fu and Li's D and Tajima's D , and Bayesian skyline plots revealed population expansion occurring in the mid-to-late Pleistocene for every lineage, regardless of size or proximity to formerly glaciated areas. Population expansion for lineages found east of the Mississippi River occurred earlier and was much greater than those found west of the River. PMID:18093846

  15. Evidence for deposition of 10 million tonnes of impact spherules across four continents 12,800 y ago

    NASA Astrophysics Data System (ADS)

    Wittke, James H.; Weaver, James C.; Bunch, Ted E.; Kennett, James P.; Kennett, Douglas J.; Moore, Andrew M. T.; Hillman, Gordon C.; Tankersley, Kenneth B.; Goodyear, Albert C.; Moore, Christopher R.; Daniel, I. Randolph, Jr.; Ray, Jack H.; Lopinot, Neal H.; Ferraro, David; Israde-Alcántara, Isabel; Bischoff, James L.; DeCarli, Paul S.; Hermes, Robert E.; Kloosterman, Johan B.; Revay, Zsolt; Howard, George A.; Kimbel, David R.; Kletetschka, Gunther; Nabelek, Ladislav; Lipo, Carl P.; Sakai, Sachiko; West, Allen; Firestone, Richard B.

    2013-06-01

    Airbursts/impacts by a fragmented comet or asteroid have been proposed at the Younger Dryas onset (12.80 ± 0.15 ka) based on identification of an assemblage of impact-related proxies, including microspherules, nanodiamonds, and iridium. Distributed across four continents at the Younger Dryas boundary (YDB), spherule peaks have been independently confirmed in eight studies, but unconfirmed in two others, resulting in continued dispute about their occurrence, distribution, and origin. To further address this dispute and better identify YDB spherules, we present results from one of the largest spherule investigations ever undertaken regarding spherule geochemistry, morphologies, origins, and processes of formation. We investigated 18 sites across North America, Europe, and the Middle East, performing nearly 700 analyses on spherules using energy dispersive X-ray spectroscopy for geochemical analyses and scanning electron microscopy for surface microstructural characterization. Twelve locations rank among the world's premier end-Pleistocene archaeological sites, where the YDB marks a hiatus in human occupation or major changes in site use. Our results are consistent with melting of sediments to temperatures >2,200 °C by the thermal radiation and air shocks produced by passage of an extraterrestrial object through the atmosphere; they are inconsistent with volcanic, cosmic, anthropogenic, lightning, or authigenic sources. We also produced spherules from wood in the laboratory at >1,730 °C, indicating that impact-related incineration of biomass may have contributed to spherule production. At 12.8 ka, an estimated 10 million tonnes of spherules were distributed across ∼50 million square kilometers, similar to well-known impact strewnfields and consistent with a major cosmic impact event.

  16. Multi-model climate impact assessment and intercomparison for three large-scale river basins on three continents

    NASA Astrophysics Data System (ADS)

    Vetter, T.; Huang, S.; Aich, V.; Yang, T.; Wang, X.; Krysanova, V.; Hattermann, F.

    2015-01-01

    Climate change impacts on hydrological processes should be simulated for river basins using validated models and multiple climate scenarios in order to provide reliable results for stakeholders. In the last 10-15 years, climate impact assessment has been performed for many river basins worldwide using different climate scenarios and models. However, their results are hardly comparable, and do not allow one to create a full picture of impacts and uncertainties. Therefore, a systematic intercomparison of impacts is suggested, which should be done for representative regions using state-of-the-art models. Only a few such studies have been available until now with the global-scale hydrological models, and our study is intended as a step in this direction by applying the regional-scale models. The impact assessment presented here was performed for three river basins on three continents: the Rhine in Europe, the Upper Niger in Africa and the Upper Yellow in Asia. For that, climate scenarios from five general circulation models (GCMs) and three hydrological models, HBV, SWIM and VIC, were used. Four representative concentration pathways (RCPs) covering a range of emissions and land-use change projections were included. The objectives were to analyze and compare climate impacts on future river discharge and to evaluate uncertainties from different sources. The results allow one to draw some robust conclusions, but uncertainties are large and shared differently between sources in the studied basins. Robust results in terms of trend direction and slope and changes in seasonal dynamics could be found for the Rhine basin regardless of which hydrological model or forcing GCM is used. For the Niger River, scenarios from climate models are the largest uncertainty source, providing large discrepancies in precipitation, and therefore clear projections are difficult to do. For the Upper Yellow basin, both the hydrological models and climate models contribute to uncertainty in the

  17. Continent-wide increase of water-use efficiency in vegetation during severe droughts of the recent decade

    NASA Astrophysics Data System (ADS)

    Peters, Wouter; van der Velde, Ivar; Miller, John. B.; Tans, Pieter P.; Vaughn, Bruce; White, James W. C.

    2015-04-01

    Recent severe droughts in Europe, Russia, China, and North America have caused widespread decline of agricultural yield and reduction of forest carbon uptake during the past decade. During droughts plants limit their water-loss at the expense of carbon uptake by partially closing their stomata, which increases the intrinsic water-use efficiency defined as the ratio of gross primary production to stomatal conductance. Here we present new evidence on this drought response of terrestrial vegetation derived from year-to-year changes in the 13C:12C stable isotope ratio in atmospheric CO2 (δ13C). Observations from more than 50,000 flask samples from a global monitoring network show a strong increase in water-use efficiency over continent-wide scales during severe droughts in Europe (2003, 2006), Russia (2010), and the United States (2002). This large-scale area-integrated vegetation drought response can not be measured from laboratory experiments or local-scale field studies and the atmospheric δ13C record thus offers a unique perspective on large-scale vegetation drought dynamics. Independent evidence from multiple eddy-covariance sites supports our inverse model interpretation of the observed global atmospheric δ13C record. With the parameterized stomatal conductance and soil moisture response used in our study, as well as many current climate models, our vegetation model underestimates this increase in water-use efficiency during severe droughts. We therefore suggest minor modifications to better reproduce the observations. We conclude that the global δ13C record provides a new opportunity to test and improve interannual drought dynamics in coupled biosphere-atmosphere models for CO2.

  18. Evidence for deposition of 10 million tonnes of impact spherules across four continents 12,800 y ago.

    PubMed

    Wittke, James H; Weaver, James C; Bunch, Ted E; Kennett, James P; Kennett, Douglas J; Moore, Andrew M T; Hillman, Gordon C; Tankersley, Kenneth B; Goodyear, Albert C; Moore, Christopher R; Daniel, I Randolph; Ray, Jack H; Lopinot, Neal H; Ferraro, David; Israde-Alcántara, Isabel; Bischoff, James L; DeCarli, Paul S; Hermes, Robert E; Kloosterman, Johan B; Revay, Zsolt; Howard, George A; Kimbel, David R; Kletetschka, Gunther; Nabelek, Ladislav; Lipo, Carl P; Sakai, Sachiko; West, Allen; Firestone, Richard B

    2013-06-01

    Airbursts/impacts by a fragmented comet or asteroid have been proposed at the Younger Dryas onset (12.80 ± 0.15 ka) based on identification of an assemblage of impact-related proxies, including microspherules, nanodiamonds, and iridium. Distributed across four continents at the Younger Dryas boundary (YDB), spherule peaks have been independently confirmed in eight studies, but unconfirmed in two others, resulting in continued dispute about their occurrence, distribution, and origin. To further address this dispute and better identify YDB spherules, we present results from one of the largest spherule investigations ever undertaken regarding spherule geochemistry, morphologies, origins, and processes of formation. We investigated 18 sites across North America, Europe, and the Middle East, performing nearly 700 analyses on spherules using energy dispersive X-ray spectroscopy for geochemical analyses and scanning electron microscopy for surface microstructural characterization. Twelve locations rank among the world's premier end-Pleistocene archaeological sites, where the YDB marks a hiatus in human occupation or major changes in site use. Our results are consistent with melting of sediments to temperatures >2,200 °C by the thermal radiation and air shocks produced by passage of an extraterrestrial object through the atmosphere; they are inconsistent with volcanic, cosmic, anthropogenic, lightning, or authigenic sources. We also produced spherules from wood in the laboratory at >1,730 °C, indicating that impact-related incineration of biomass may have contributed to spherule production. At 12.8 ka, an estimated 10 million tonnes of spherules were distributed across ∼50 million square kilometers, similar to well-known impact strewnfields and consistent with a major cosmic impact event. PMID:23690611

  19. Habitat productivity constrains the distribution of social spiders across continents – case study of the genus Stegodyphus

    PubMed Central

    2013-01-01

    Introduction Sociality has evolved independently multiple times across the spider phylogeny, and despite wide taxonomic and geographical breadth the social species are characterized by a common geographical constrain to tropical and subtropical areas. Here we investigate the environmental factors that drive macro-ecological patterns in social and solitary species in a genus that shows a Mediterranean–Afro-Oriental distribution (Stegodyphus). Both selected drivers (productivity and seasonality) may affect the abundance of potential prey insects, but seasonality may further directly affect survival due to mortality caused by extreme climatic events. Based on a comprehensive dataset including information about the distribution of three independently derived social species and 13 solitary congeners we tested the hypotheses that the distribution of social Stegodyphus species relative to solitary congeners is: (1) restricted to habitats of high vegetation productivity and (2) constrained to areas with a stable climate (low precipitation seasonality). Results Using spatial logistic regression modelling and information-theoretic model selection, we show that social species occur at higher vegetation productivity than solitary, while precipitation seasonality received limited support as a predictor of social spider occurrence. An analysis of insect biomass data across the Stegodyphus distribution range confirmed that vegetation productivity is positively correlated to potential insect prey biomass. Conclusions Habitat productivity constrains the distribution of social spiders across continents compared to their solitary congeners, with group-living in spiders being restricted to areas with relatively high vegetation productivity and insect prey biomass. As known for other taxa, permanent sociality likely evolves in response to high predation pressure and imposes within-group competition for resources. Our results suggest that group living is contingent upon productive

  20. Evidence for deposition of 10 million tonnes of impact spherules across four continents 12,800 y ago

    USGS Publications Warehouse

    Wittke, James H.; Weaver, James C.; Bunch, Ted E.; Kennett, James P.; Kennett, Douglas J.; Moore, Andrew M.T.; Hillman, Gordon C.; Tankersly, Kenneth B.; Goodyear, Albert C.; Moore, Christopher R.; Daniel, I. Randolph, Jr.; Ray, Jack H.; Lopinot, Neal H.; Ferraro, David; Israde-Alcántara, Isabel; Bischoff, James L.; DeCarli, Paul S.; Hermes, Robert E.; Kloosterman, Johan B.; Revay, Zsolt; Howard, George A.; Kimbel, David R.; Kletetschka, Gunther; Nabelek, Ladislav; Lipo, Carl P.; Sakai, Sachiko; West, Allen; Firestone, Richard B.

    2013-01-01

    Airbursts/impacts by a fragmented comet or asteroid have been proposed at the Younger Dryas onset (12.80 ± 0.15 ka) based on identification of an assemblage of impact-related proxies, including microspherules, nanodiamonds, and iridium. Distributed across four continents at the Younger Dryas boundary (YDB), spherule peaks have been independently confirmed in eight studies, but unconfirmed in two others, resulting in continued dispute about their occurrence, distribution, and origin. To further address this dispute and better identify YDB spherules, we present results from one of the largest spherule investigations ever undertaken regarding spherule geochemistry, morphologies, origins, and processes of formation. We investigated 18 sites across North America, Europe, and the Middle East, performing nearly 700 analyses on spherules using energy dispersive X-ray spectroscopy for geochemical analyses and scanning electron microscopy for surface microstructural characterization. Twelve locations rank among the world’s premier end-Pleistocene archaeological sites, where the YDB marks a hiatus in human occupation or major changes in site use. Our results are consistent with melting of sediments to temperatures >2,200 °C by the thermal radiation and air shocks produced by passage of an extraterrestrial object through the atmosphere; they are inconsistent with volcanic, cosmic, anthropogenic, lightning, or authigenic sources. We also produced spherules from wood in the laboratory at >1,730 °C, indicating that impact-related incineration of biomass may have contributed to spherule production. At 12.8 ka, an estimated 10 million tonnes of spherules were distributed across ∼50 million square kilometers, similar to well-known impact strewnfields and consistent with a major cosmic impact event.

  1. Thermal history of the 1.1-Ga Nonesuch Formation, North American mid-continent rift, White Pine, Michigan

    SciTech Connect

    Price, K.L.; Huntoon, J.E.; McDowell, S.D.

    1996-01-01

    The Nonesuch Formation, a black siltstone, was deposited in the Lake Superior portion of the mid-continent rift system during middle Proterozoic rifting. Despite its age of nearly 1.1 Ga, the Nonesuch Formation contains liquid petroleum and solid pyrobitumen. Numerical modeling techniques were used in this study to constrain the thermal history of the Nonesuch Formation at White Pine, Michigan. Thermal modeling addresses two issues: (1) the utility of illite-smectite expandability as a limiting parameter for describing the thermal history of ancient (Proterozoic) sedimentary rocks, and (2) the potential for hydrocarbon maturation within the Nonesuch Formation at White Pine. A range of potential burial histories for the Nonesuch Formation was constructed based on geological evidence. Time-temperature histories were calculated for each burial history model assuming one-dimensional, transient, conductive heat flow. Results of numerical time-temperature models were then evaluated on the basis of organic and inorganic thermal maturity indicators including Rock-Eval{reg_sign} pyrolysis data and biomarker indices (correlated to equivalent vitrinite reflectance values), in addition to illite-smectite expendability. Modeling results demonstrate that a combination of elevated basal heat flow and rapid burial during the Proterozoic is required to produce the observed thermal maturities at White Pine, Michigan. More specifically, modeling indicates that maximum temperatures for the Nonesuch Formation, 110 to 125{degrees}C, were reached at about 1075 Ma, coincident with a maximum burial depth of about 6 km, although 4 km represents a more plausible value. The results support a thermal history consistent with in-situ oil generation at White Pine; however, thermal modeling alone cannot rule out the possibility that oil was generated and expelled elsewhere and migrated into the area with fluids expelled during an episode of postrift compression.

  2. Correlation and implications of results from recent wildcat wells in Mid-Continent rift in northeastern Kansas

    SciTech Connect

    Newll, K.D.; Berendsen, P.; Doveton, J.H.; Watney, W.L. )

    1989-08-01

    Three recent wildcat wells, the Texaco 1 Poersch (Sec. 31, T5S, R5E), the Producers Engineering et al 1 Finn (Sec. 4, T4S, R7E), and 1 Freiderich (Sec. 8, T7S, R5E), respectively, penetrated 8,455, 1,848, and 1,781 ft of Precambrian rocks in the Mid-Continent rift system (MRS) in Kansas. The Producers Engineering et al 1 Finn, which is 18 mi northeast of the Texaco 1 Poersch, encountered mostly arkosic sandstones and shales. The Producers Engineering et al 1 Freiderich, 7 mi south of the Texaco 1 Poersch, penetrated mafic igneous and volcanic clastic rocks. In contrast, the Poersch well drilled approximately 90% mafic igneous rocks and 10% arkosic sandstones in the upper 4,584 ft of the Precambrian section. In the lower 3,871 ft of the well, the proportions of these rock-types were reversed. No Precambrian petroleum source rocks were found in the Poersch and Freiderich wells, but 300 ft of gray siltstone (approximately 0.5% TOC) were encountered directly below the Precambrian unconformity in the Finn well. The Finn well also has significantly more red siltstones than the Poersch well, thereby possibly indicating more distal lacustrine or low-energy marine environments of deposition. Alluvial fans and playas are probably responsible for most of the sedimentary deposition in the Poersch well. Geophysical and well data indicate the MRS in northeastern Kansas is divided into small subbasins that probably are only a few tens of square miles in areal extent. Abrupt facies changes and complicated structure make lithostratigraphic correlations difficult.

  3. Crustal Structure of and near the North American Mid-continent Rift System from Receiver Function Studies

    NASA Astrophysics Data System (ADS)

    Zhang, H.; van der Lee, S.; Wolin, E.; Bollmann, T. A.; Revenaugh, J.; Aleqabi, G. I.; Wiens, D. A.; Frederiksen, A. W.; Darbyshire, F. A.

    2014-12-01

    The more than 1000-km-long main branch of the mid-continent rift system (MRS) near Lake Superior and the Minnesota-Wisconsin border nearly took North America apart, but ceased rifting soon after it began. Thermal and magmatic events and subsidence- related sedimentary processes significantly changed the structure of the upper crust across and along the MRS. To map the depth extent and lateral changes in deep lithospheric structure related to the MRS, we estimated and studied receiver functions (RFs) from 82 SPREE (Superior Province Rifting EarthScope Experiment) broadband seismic stations and seven EarthScope Transportable Array stations. We inverted the RFs for depths of seismic-velocity discontinuities and shear-velocity structure of the crust. The RFs for each station are derived from the deconvolution of the radial component with the vertical component in the time domain (Ammon et al., 1991). Using a relatively high corner frequency in the deconvolution passband helps us resolve multiple layers within the crust. The most prominent feature of the RFs is the P-to-S wave converted at the Moho (Fig. 1), which reflects the contrast in rock properties between the lower crust and upper mantle. This Moho-generated P-to-S converted wave is very clear in RFs for stations outside of the MRS. Inside the MRS, the RFs are more ambiguous and suggestive of a basal crustal layer with shear velocities in between typical lower crust and upper mantle values. There is more variation among the RFs for stations within the MRS than among stations outside of the MRS.

  4. Dalbavancin Activity When Tested against Streptococcus pneumoniae Isolated in Medical Centers on Six Continents (2011 to 2014).

    PubMed

    Jones, Ronald N; Schuchert, Jason E; Mendes, Rodrigo E

    2016-06-01

    Dalbavancin, a novel lipoglycopeptide, was approved for use in 2014 by regulatory agencies in the United States and Europe for the treatment of skin and skin structure infections. The activity of dalbavancin was also widely assessed by determination of its activity against Streptococcus pneumoniae clinical isolates collected from patients on six continents monitored during two time intervals (2011 to 2013 and 2014). A total of 18,186 pneumococcal isolates were obtained from 49 nations and submitted to a monitoring laboratory as part of the SENTRY Antimicrobial Surveillance Program for reference susceptibility testing. The potency of dalbavancin against S. pneumoniae was consistent across the years that it was monitored, with the MIC50 and MIC90 being 0.015 and 0.03 μg/ml, respectively, and all isolates were inhibited by ≤0.12 μg/ml. The activity of dalbavancin was not adversely influenced by nonsusceptibility to β-lactams (ceftriaxone or penicillin), macrolides, clindamycin, fluoroquinolones, or tetracyclines or multidrug resistance (MDR). Regional variations in dalbavancin activity were not detected, but S. pneumoniae strains isolated in the Asia-Pacific region were more likely to be nonsusceptible to penicillin and ceftriaxone as well as to be MDR than strains isolated in North or South America and Europe. Direct comparisons of potency illustrated that dalbavancin (MIC50 and MIC90, 0.015 and 0.03 μg/ml, respectively) was 16-fold or more active than vancomycin (MIC50, 0.25 μg/ml), linezolid (MIC50, 1 μg/ml), levofloxacin (MIC50, 1 μg/ml), ceftriaxone (MIC90, 1 μg/ml), and penicillin (MIC90, 2 μg/ml). In conclusion, dalbavancin had potent and consistent activity against this contemporary (2011 to 2014) collection of S. pneumoniae isolates. PMID:27001811

  5. Morphological analysis of the urethral muscle of the male pig with relevance to urinary continence and micturition.

    PubMed

    Ragionieri, Luisa; Ravanetti, Francesca; Gazza, Ferdinando; Botti, Maddalena; Ivanovska, Ana; Cacchioli, Antonio

    2016-03-01

    To investigate whether the pig could be considered a suitable model to study lower urinary tract function and dysfunction, the pelvic urethra of 24 slaughtered male pigs were collected, and the associated muscles were macroscopically, histologically and histochemically analyzed. In cross-sections of the urethra, a muscular complex composed of an inner layer of smooth muscle and an outer layer of striated muscle that are not separated by fascial planes was observed. A tunica muscularis, composed of differently oriented smooth muscle bundles, is only evident in the proximal part of the pelvic urethra while, in the remaining part, it contributes to form the prostatic fibromuscular stroma. The striated urethral muscle surrounds the pelvic urethra in a horseshoe-like configuration with a dorsal longitudinal raphe, extending from the bladder neck to the central tendon of perineum. Proximally to the bladder, it is constituted of slow-twitch and fast-twitch myofibers of very small diameter, and embedded in an abundant collagen and elastic fiber net. Moving caudally it is gradually encircled and then completely substituted by larger and compact myofibers, principally presenting circular orientation and fast-twitch histochemical characteristics. So, like in humans, the cranial tract of the muscular system surrounding the pelvic urethra is principally composed of smooth musculature. The striated component cranially may have a role in blocking retrograde ejaculation, while the middle and caudal tracts may facilitate urine and semen flow, and seem especially concerned with the rapid and forceful urethral closure during active continence. Some differences in the morphology and structure between pigs and humans seem due to the different morphology of the 'secondary' sexual organs that develop from the urethral wall and to the different effect of gravity on the mechanics of the urinary system in quadruped and bipedal mammals. PMID:26573248

  6. Nature of basement highs in ultra-distal ocean-continent transitions: on- and off-shore examples

    NASA Astrophysics Data System (ADS)

    Epin, Marie-Eva; Manatschal, Gianreto

    2016-04-01

    Despite the fact that many studies investigated magma-poor rifted margins, there are still questions that are related to the nature and the origin of basement highs in ultra-distal Ocean-Continent Transitions (OCT). Indeed it has been observed that the morphology of the OCT of magma-poor rifted margins is structured and complex. The aim of this study is to determine the nature of these basement highs, their 3D morphology, the processes associated to their creation, and the timing related to their formation. To do this, we focused on distal seismic lines with well data from the Iberia and Newfoundland margins and on field observations of the Platta nappe, which exposes an about 300 km² large, little overprinted remnant of a fossil OCT belonging to the Alpine Tethys, exposed in the area of Bivio in SE Switzerland. The first results are the establishment of criteria allowing the identification of the different types of basement highs or groups of basement highs using offshore and onshore data. The main criteria are: the top-basement morphology, seismic reflectivity patterns, rooting depth of basement highs, the size, the related sedimentary architecture, the relative location in the margin, and if possible to determine, the magmatic budget. These criteria allow us to define 4 different types of highs that are: 1) footwall crustal wedges, 2) hanging wall extensional allochthon blocks, 3) peridotite ridges, and 4) outer highs. The overall observations provide important information on the temporal and spatial organization of the structural and magmatic systems. These systems are at the origin of the creation of ultra-distal OCTs which are important for the understanding of the processes controlling the final rifting stage. The goal of this study is to use an observation driven approach and to create identification criteria that can be used to describe the nature of basement highs at not yet drilled distal magma-poor rifted margins.

  7. Evidence for deposition of 10 million tonnes of impact spherules across four continents 12,800 y ago

    PubMed Central

    Wittke, James H.; Weaver, James C.; Bunch, Ted E.; Kennett, James P.; Kennett, Douglas J.; Moore, Andrew M. T.; Hillman, Gordon C.; Tankersley, Kenneth B.; Goodyear, Albert C.; Moore, Christopher R.; Daniel, I. Randolph; Ray, Jack H.; Lopinot, Neal H.; Ferraro, David; Israde-Alcántara, Isabel; Bischoff, James L.; DeCarli, Paul S.; Hermes, Robert E.; Kloosterman, Johan B.; Revay, Zsolt; Howard, George A.; Kimbel, David R.; Kletetschka, Gunther; Nabelek, Ladislav; Lipo, Carl P.; Sakai, Sachiko; West, Allen; Firestone, Richard B.

    2013-01-01

    Airbursts/impacts by a fragmented comet or asteroid have been proposed at the Younger Dryas onset (12.80 ± 0.15 ka) based on identification of an assemblage of impact-related proxies, including microspherules, nanodiamonds, and iridium. Distributed across four continents at the Younger Dryas boundary (YDB), spherule peaks have been independently confirmed in eight studies, but unconfirmed in two others, resulting in continued dispute about their occurrence, distribution, and origin. To further address this dispute and better identify YDB spherules, we present results from one of the largest spherule investigations ever undertaken regarding spherule geochemistry, morphologies, origins, and processes of formation. We investigated 18 sites across North America, Europe, and the Middle East, performing nearly 700 analyses on spherules using energy dispersive X-ray spectroscopy for geochemical analyses and scanning electron microscopy for surface microstructural characterization. Twelve locations rank among the world’s premier end-Pleistocene archaeological sites, where the YDB marks a hiatus in human occupation or major changes in site use. Our results are consistent with melting of sediments to temperatures >2,200 °C by the thermal radiation and air shocks produced by passage of an extraterrestrial object through the atmosphere; they are inconsistent with volcanic, cosmic, anthropogenic, lightning, or authigenic sources. We also produced spherules from wood in the laboratory at >1,730 °C, indicating that impact-related incineration of biomass may have contributed to spherule production. At 12.8 ka, an estimated 10 million tonnes of spherules were distributed across ∼50 million square kilometers, similar to well-known impact strewnfields and consistent with a major cosmic impact event. PMID:23690611

  8. The Vulcan Project: Recent advances and emissions estimation for the NACP mid-continent intensive campaign region

    NASA Astrophysics Data System (ADS)

    Gurney, K. R.; Zhou, Y.; Geethakumar, S.; Godbole, A.; Mendoza, D. L.; Vaidhyanathan, M.; Sahni, N.

    2009-12-01

    The Vulcan Project has quantified 2002 fossil fuel CO2 for the US at the sub-county/hourly scale and is a key component of attributing CO2 fluxes within the North American Carbon Program. Vulcan approached quantification of CO2 emissions by leveraging information already contained within regulatory and monitoring agencies including the US EPA’s Acid Rain Program, the EPA’s National Emissions Inventory for the assessment of nationally regulated air pollution, the Department of Energy, the U.S. Census and the Department of Transportation. By utilizing the inventory emissions of carbon monoxide combined with fuel/device-specific emission factors, we have calculated CO2 emissions for industrial point sources, power plants, mobile sources, residential and commercial sectors with information on fuel used and source classification information. In this presentation, I provide critical recent advances in the Vulcan Project with particular emphasis on our contribution to the NACP mid-continent intensive campaign. Version 1.2 of the Vulcan fossil fuel CO2 emissions inventory includes the 2008 US Census road atlas, overcoming many of the missing roads and links that were prevalent in previous road atlas releases. This offers better spatial allocation of the onroad emissions. Figure 1 shows the improved road layer density for the MCI study region. Furthermore the temporal dimension of onroad emissions have been improved through the use of hourly traffic monitoring data at roughly 6000 monitoring locations across the US. The residential and commercial sector emissions now have hourly time structure via a spatially explicit heating degree day calculation utilizing the North American Regional Reanalysis temperature output. Finally, we have generated a multiyear (1997-2008) data product for the MCI region through use of Energy Information Administration state-level fuel sales data. Figure 1. improved road density via utilization of the new 2008 US census road layer. Left

  9. Evolution of the intercontinental disjunctions in six continents in the Ampelopsis clade of the grape family (Vitaceae)

    PubMed Central

    2012-01-01

    Background The Ampelopsis clade (Ampelopsis and its close allies) of the grape family Vitaceae contains ca. 43 species disjunctly distributed in Asia, Europe, North America, South America, Africa, and Australia, and is a rare example to study both the Northern and the Southern Hemisphere intercontinental disjunctions. We reconstruct the temporal and spatial diversification of the Ampelopsis clade to explore the evolutionary processes that have resulted in their intercontinental disjunctions in six continents. Results The Bayesian molecular clock dating and the likelihood ancestral area analyses suggest that the Ampelopsis clade most likely originated in North America with its crown group dated at 41.2 Ma (95% HPD 23.4 - 61.0 Ma) in the middle Eocene. Two independent Laurasian migrations into Eurasia are inferred to have occurred in the early Miocene via the North Atlantic land bridges. The ancestor of the Southern Hemisphere lineage migrated from North America to South America in the early Oligocene. The Gondwanan-like pattern of intercontinental disjunction is best explained by two long-distance dispersals: once from South America to Africa estimated at 30.5 Ma (95% HPD 16.9 - 45.9 Ma), and the other from South America to Australia dated to 19.2 Ma (95% HPD 6.7 - 22.3 Ma). Conclusions The global disjunctions in the Ampelopsis clade are best explained by a diversification model of North American origin, two Laurasian migrations, one migration into South America, and two post-Gondwanan long-distance dispersals. These findings highlight the importance of both vicariance and long distance dispersal in shaping intercontinental disjunctions of flowering plants. PMID:22316163

  10. Deep Mantle Dynamics under the North American Continent Drives Localised Flow and Stress Below the New Madrid Seismic Zone

    NASA Astrophysics Data System (ADS)

    Forte, A. M.; Mitrovica, J. X.; Moucha, R.; Simmons, N. A.; Grand, S. P.

    2007-12-01

    The origin of intraplate earthquakes represents one of the outstanding problems in modern geophysical research, and the major earthquake sequence that struck the central Mississippi River Valley in 1811-1812, the so-called New Madrid seismic sequence, has become a principal target of this research. As Johnston and Schweig (1996) have noted, the occurrence of such large magnitude earthquakes in "stable" North American crust, far from any plate boundaries, remains an enigma. To understand the possible origin of this enigmatic seismic activity we have developed a new high resolution model of mantle flow below North America. The model is constrained by simultaneously inverting global seismic and mantle-convection data sets and it includes an explicit treatment of the positive chemical buoyancy of the continental tectosphere. Moreover, it adopts a depth dependent mantle viscosity structure which reconciles both glacial isostatic adjustment (GIA) and convection data. The flow model successfully reproduces plate velocities and observations of surface gravity and topography, including the continent-scale quasi-linear depression (after corrections for GIA and crustal heterogeneity) extending from northern Alaska to Venezuela. The predictions also match lithospheric flow and stress fields inferred from local and regional measurements of seismic anisotropy and surface deformation. We demonstrate that these signals are largely driven by viscous flow coupled to density anomalies within the lower mantle associated with the descent of the ancient Kula-Farallon plate system. More importantly, the flow calculations elucidate how these large-scale heterogeneities give rise to flow and stress patterns below the New Madrid Seismic Zone which are favourably oriented with respect the local fault geometry in this portion of the Mississippi valley.

  11. Natural hazards and decision-making in the most densely populated country in the American continent: a 20-year perspective

    NASA Astrophysics Data System (ADS)

    Cruz Martínez, Celina; Cepeda, Jose

    2010-05-01

    With a population density of ~300 per km2, El Salvador is the most densely populated country in the American continent and the capital, San Salvador, is probably the city in the Americas most frequently hit by natural hazards, earthquakes in particular. As a consequence of a magnitude 5.4 earthquake in 1986, 1500 people were killed, with as many as one-third of these casualties associated to the collapse of engineered structures, a high rate compared to contemporary figures worldwide. Four years earlier, during a long precipitation period in September 1982, a debris flow was triggered from the summit of the San Salvador volcano and travelled ~4 km for about one hour before it killed up to 500 people in an area to the North-West of the Metropolitan Area of San Salvador (AMSS). This same area had been previously hit by a similar event 50 years earlier, but with no consequences at that time since it was uninhabited. These are only some examples of the main facts that motivated the creation of the Office for Urban Planning of the Metropolitan Area of San Salvador (OPAMSS) in 1990. This institution is an autonomous municipal organisation whose functions and attributes comprise the planning and control of urban development. After 20 years of the foundation of OPAMSS, this paper presents its history and evolution, the main achievements and challenges, focusing on how the institution has been shaped by some key milestones, such as the earthquake-triggered landslide at Las Colinas neighbourhood in January 2001, which killed ~600 people in the Western AMSS, and the widespread flooding in October 2005 after the urban drainage network collapsed during Hurricane Stan. The development of OPAMSS as a key organisation in land use management and decision-making is an example that illustrates how the integration of technical and legal aspects can be oriented towards the improvement of governance at the scale of metropolitan areas.

  12. Elevated Mississippi River discharge during glacial times: A 6,000 year wet period on the North American continent

    NASA Astrophysics Data System (ADS)

    Hill, H. W.; Hollander, D. J.; Flower, B. P.; Quinn, T. M.

    2005-12-01

    Sedimentary basins proximal to major rivers can provide a coherent, high-resolution assessment of the oceanic and continental responses to changing hydrologic regimes attributed to abrupt climate variability. Documenting these regime changes under climatic extremes, including glacial time periods that are often considered cold and dry in temperate North America, is important to understand the potential impacts associated with changing hydrologic conditions. The Orca Basin in the northern Gulf of Mexico (GOM) is ideally situated to record inputs from the Mississippi River and to relate these inputs to changing moisture balance over North America. We use organic and inorganic geochemical analyses to document a 6 ka wet period on the North American continent from 32-38 ka, during glacial Marine Isotope Stage 3, that is decoupled from Laurentide Ice Sheet meltwater dynamics over this interval. This wet period is inferred from a 5-fold increase in the input of long-chain n-alkanes derived from terrestrial plants and concurrent increases in the percent coarse fraction and insoluble residue in the bulk sediment. Associated with the wet period, a 5-fold increase in the algal derived n-alkanes implies that continentally sourced nutrients supported marine production. A 0.6 ‰ increase in the inorganic δ13CG. ruber and a shift in the δ13C of bulk organic matter from -26 to -23 ‰ also points to an increase in marine production. Further, a 1°C cooling in SST, as determined from G.ruber Mg-derived temperatures, is synchronous with the fluvial inputs. Our evidence suggests that the GOM served as an enhanced moisture source to the Mississippi River basin during this interval, perhaps via the southern displacement of frontal weather systems, resulting in oceanic physical and biological changes. Results of this study will be discussed in the context of regionally defined climate patterns, continental paleorecords and global circulation models.

  13. What is responsible for development of the Asian-Pacific transition zone: The geodynamics of oceanic plates or the Asian continent?

    NASA Astrophysics Data System (ADS)

    Utkin, V. P.

    2016-03-01

    The main unusual feature of tectogenesis of the Asian-Pacific transition zone in the Mesozoic-Cenozoic consists in the formation of left-lateral strike-slip faults, which form the East Asian global shear zone with paragenesis of its constituent variously oriented fault systems. Paragenetic analysis has revealed that continental blocks of the Asian-Pacific transition zone were displaced along systems of transit left-lateral strike-slip faults of the East Asian global shear zone by hundreds of kilometers in the southerly to southwesterly direction due to tectonic activity of the Asian continent, which drifted southwestward. This process was accompanied by the formation of compression and extension structures. Otherwise, it is difficult to explain the structuring of the overhanging margin of the continent by subduction of oceanic lithospheric plates in the northerly to northwesterly direction opposite relative to the displacement of the continental crust as is usually thought.

  14. A harbinger of plate tectonics: a commentary on Bullard, Everett and Smith (1965) ‘The fit of the continents around the Atlantic’

    PubMed Central

    Dewey, John F.

    2015-01-01

    In the 1960s, geology was transformed by the paradigm of plate tectonics. The 1965 paper of Bullard, Everett and Smith was a linking transition between the theories of continental drift and plate tectonics. They showed, conclusively, that the continents around the Atlantic were once contiguous and that the Atlantic Ocean had grown at rates of a few centimetres per year since the Early Jurassic, about 160 Ma. They achieved fits of the continental margins at the 500 fathom line (approx. 900 m), not the shorelines, by minimizing misfits between conjugate margins and finding axes, poles and angles of rotation, using Euler's theorem, that defined the unique single finite difference rotation that carried congruent continents from contiguity to their present positions, recognizing that the real motion may have been more complex around a number of finite motion poles. Critically, they were concerned only with kinematic reality and were not restricted by considerations of the mechanism by which continents split and oceans grow. Many of the defining features of plate tectonics were explicit or implicit in their reconstructions, such as the torsional rigidity of continents, Euler's theorem, closure of the Tethyan ocean(s), major continental margin shear zones, the rapid rotation of small continental blocks (Iberia) around nearby poles, the consequent opening of small wedge-shaped oceans (Bay of Biscay), and misfit overlaps (deltas and volcanic piles) and underlaps (stretched continental edges). This commentary was written to celebrate the 350th anniversary of the journal Philosophical Transactions of the Royal Society. PMID:25750142

  15. A harbinger of plate tectonics: a commentary on Bullard, Everett and Smith (1965) 'The fit of the continents around the Atlantic'.

    PubMed

    Dewey, John F

    2015-04-13

    In the 1960s, geology was transformed by the paradigm of plate tectonics. The 1965 paper of Bullard, Everett and Smith was a linking transition between the theories of continental drift and plate tectonics. They showed, conclusively, that the continents around the Atlantic were once contiguous and that the Atlantic Ocean had grown at rates of a few centimetres per year since the Early Jurassic, about 160 Ma. They achieved fits of the continental margins at the 500 fathom line (approx. 900 m), not the shorelines, by minimizing misfits between conjugate margins and finding axes, poles and angles of rotation, using Euler's theorem, that defined the unique single finite difference rotation that carried congruent continents from contiguity to their present positions, recognizing that the real motion may have been more complex around a number of finite motion poles. Critically, they were concerned only with kinematic reality and were not restricted by considerations of the mechanism by which continents split and oceans grow. Many of the defining features of plate tectonics were explicit or implicit in their reconstructions, such as the torsional rigidity of continents, Euler's theorem, closure of the Tethyan ocean(s), major continental margin shear zones, the rapid rotation of small continental blocks (Iberia) around nearby poles, the consequent opening of small wedge-shaped oceans (Bay of Biscay), and misfit overlaps (deltas and volcanic piles) and underlaps (stretched continental edges). This commentary was written to celebrate the 350th anniversary of the journal Philosophical Transactions of the Royal Society. PMID:25750142

  16. Long-term follow-up after ileocaecal continent cutaneous urinary diversion (Mainz I pouch): A retrospective study of a monocentric experience

    PubMed Central

    Khalil, Fahd; Fellahi, Saad; Ouslim, Hicham; Mhanna, Tarik; El Houmaidi, Amine; Aynaou, Mohammed; Boteng, Paapa Dua; Barki, Ali; Nouini, Yassine

    2015-01-01

    Objective To assess the long-term follow-up after ileocaecal continent cutaneous reservoir (ICCR) and to review the late complications. Patients and methods In all, 756 patients underwent an ICCR in our department, with long-term follow-up data available in 50 patients. The inclusion criterion was ICCR regardless of the indication and the exclusion criteria were orthotopic neobladder or other continent urinary diversions not performed with the ileocaecum. Patients were followed to record primary outcomes and late complications. Complications were stratified according to the Clavien–Dindo classification. Results The mean patient age was 44 years and pelvic malignancies were the first indication for urinary diversion. The mean (range) follow-up was 19 (9–36) years. A stoma stenosis was the most frequent outlet-related complication requiring re-intervention, followed by ischaemic outlet degeneration, and stoma incontinence. Six renal units (RUs) developed obstruction at the anastomotic site and were managed by open surgery. Three RUs had to be removed due to deterioration. A dederivation was necessary in three patients (6%). Conclusion The ICCR is a safe and established technique when an orthotopic pouch is impossible. The long-term follow-up shows acceptable complication rates and satisfactory continence conditions. However, large population studies are necessary to confirm this observation. PMID:26609442

  17. Phosphodiesterase type 5 inhibitor administered immediately after radical prostatectomy temporarily increases the need for incontinence pads, but improves final continence status

    PubMed Central

    Yamashita, Shinichi; Ito, Akihiro; Kawasaki, Yoshihide; Izumi, Hideaki; Kawamorita, Naoki; Adachi, Hisanobu; Mitsuzuka, Koji; Arai, Yoichi

    2016-01-01

    Purpose To evaluate the effects of phosphodiesterase type 5 inhibitor (PDE5i) on urinary continence recovery after bilateral nerve-sparing radical prostatectomy (BNSRP). Materials and Methods Between 2002 and 2012, 137 of 154 consecutive patients who underwent BNSRP in our institution retrospectively divided into 3 groups that included patients taking PDE5i immediately after surgery (immediate PDE5i group, n=41), patients starting PDE5i at an outpatient clinic after discharge (PDE5i group, n=56), and patients taking no medication (non-PDE5i group, n=40). Using self-administered questionnaires, the proportion of patients who did not require incontinence pads (pad-free patients) was calculated preoperatively and at 1, 3, 6, 12, 18, and 24 months after BNSRP. Severity of incontinence was determined based on the pad numbers and then compared among the 3 groups. Results Proportions of pad-free patients and severity of incontinence initially deteriorated in all of the groups to the lowest values soon after undergoing BNSRP, with gradual improvement noted thereafter. The deterioration was most prominent in the immediate PDE5i group. As compared to the non-PDE5i group, both the PDE5i and immediate PDE5i groups exhibited a better final continence status. Conclusions PDE5i improves final continence status. However, administration of PDE5i immediately after surgery causes a distinct temporary deterioration in urinary incontinence.

  18. A Comparison of Food Supply from 1984 to 2009 and Degree of Dietary Westernization in Taiwan with Asian Countries and World Continents

    PubMed Central

    Peng, Cheau-Jane; Lin, Cheng-Yao; Guo, How-Ran

    2015-01-01

    Objective. To compare quality, quantity, and trends of food supply from 1984 to 2009 and degree of food westernization in Taiwan with Asian countries and world continents by using food balance data. Methods. We compiled data from food balance sheets of Taiwan and Food and Agriculture Organization, including five continents and three most populated countries each in Eastern, Southern, and Southeastern Asia over the period 1984–2009. Quantity of food supply per capita was referenced to Taiwan food guides. The population-weighted means of food supply from Europe, North America, South America, and Australia and New Zealand continents in terms of energy and nutrient distributions, animal/plant sources, and sugar/alcohol contribution were used as indicators of westernization. Trends of food supply per capita of six food groups were plotted, and linear regression was applied to evaluate food changes. Findings. Taiwan's food supply provided sufficient quantity in food energy, with the lowest cereals/roots supply and rice to wheat ratio, but the highest meat and oil supplies per capita among the 10 studied Asian countries. Taiwan food supply showed the most westernization among these countries. Conclusion. Food supply of Taiwan, although currently sufficient, indicated some security problems and high tendency of diet westernization. PMID:26295045

  19. Ocean-continent-transition and oceanic ridge structural evolution (eastern Gulf of Aden): Implications for rift to seafloor spreading processes

    NASA Astrophysics Data System (ADS)

    D'Acremont, E.; Leroy, S. D.; Beslier, M.; Autin, J.; Watremez, L.; Maia, M. A.; Gente, P.

    2009-12-01

    The rifting between Arabia and Somalia, which started around 35 Ma ago, is followed by oceanic accretion from at least 17.6 Ma leading to the present Gulf of Aden. The transition between the thinned continental and the oceanic crusts is characterized, in space and time, by an ocean-continent transition (OCT). Here, we use bathymetry, gravity, seismic reflection and magnetism from the Encens-Sheba and Encens cruises in order to constrain the structure and segmentation of the conjugate OCT as well as the oceanic ridge between two main fracture zones (Alula-Fartak and Socotra-Hadbeen). The segmentation of the initial oceanic spreading centers seem directly related to the margin structure. Then, magmatic processes and kinematics change strongly influenced the evolution of the segmentation. The OCT and the oceanic domain can be divided into two distinct areas in the study area. The Eastern area is characterized by an extremely thin OCT and oceanic crusts (< 4km), a ~30 km wide and tectonized OCT with isolated continental blocks and short axial segments. In the western area, thicker OCT and oceanic crusts (>5km), a ~15 km wide OCT with a volcanic ridge, and a 6 km thick underplated mafic body in the northern margin suggest a high melt supply. The magmatic supply observed in the western domain is probably due to an off-axis thermal anomaly located below the southern flank of the Sheba ridge, at 75 km east of the major Alula-Fartak transform fault. This suggests that the OCT and the axial ridge morphology of this domain are perturbed by post-rift volcanism, which is due to a combination of the spreading rate, a thermal anomaly, and the cold edge effect of the Alula-Fartak transform fault. The presence of the inherited Mesozoic basins (Jezar-Qamar-Gardafui basin) located on this western domain can also explain, the difference in both the structure and the nature of the OCT between the two domains. The nature of the OCT could be either (or both) exhumed lower crust or

  20. Mesoscale modeling of smoke transport over the Southeast Asian Maritime Continent: Interplay of sea breeze, trade wind, typhoon, and topography

    NASA Astrophysics Data System (ADS)

    Wang, Jun; Ge, Cui; Yang, Zhifeng; Hyer, Edward J.; Reid, Jeffrey S.; Chew, Boon-Ning; Mahmud, Mastura; Zhang, Yongxin; Zhang, Meigen

    2013-03-01

    The online-coupled Weather Research and Forecasting model with Chemistry (WRFchem) is used to simulate the transport of smoke particles over the Southeast Asian Maritime Continent during September-October 2006. In this period, dry conditions associated with the moderate El Niño event caused the largest regional biomass burning outbreak since 1997. Smoke emission in WRFchem is specified according to the Fire Locating and Modeling of Burning Emissions (FLAMBE) database derived from Moderate Resolution Imaging Spectroradiometer (MODIS) fire products. The modeled smoke transport pathway is found to be consistent with the MODIS true color images and measured mass concentration of surface PM10 (particulate matter with diameter less than 10 μm). The interplay of sea/land breezes, typhoons and storms over the subtropical western Pacific Ocean, trade winds, and topographic effects, can be clearly seen in the model simulation. The most severe smoke events in 1-5 October 2006 are found to be associated with the meteorological responses to the typhoon Xangsane (#18) over the western subtropical Pacific Ocean, which moved smoke from Sumatra eastward in the lower troposphere (below 700 hPa), forming smoke layers mixed with and above the boundary layer clouds over Borneo. In contrast, the second largest week-long smoke transport event of 15-18 October 2006 was associated with the seasonal monsoonal transition period, during which smoke plumes were wide spread over the 5°S-5°N zone as a result of (a) the near surface divergence coupled with the 700 hPa bifurcation of wind (flowing both to the west and to the east), and (b) the near-surface southeasterly and easterly winds along the equator transporting smoke from Borneo to Sumatra and Peninsular Malaysia. Analysis of data from the Cloud-Aerosol Lidar with Orthogonal Polarisation (CALIOP) shows that smoke particles in October 2006 were primarily located within 3.5 km above the surface. Smoke particles contributed roughly half

  1. Mantle flow deduced from geochemical variations in alkaline magmas of HIMU affinity from continent to ocean, northwestern Ross Sea, Antarctica

    NASA Astrophysics Data System (ADS)

    Castillo, P. R.; Panter, K. S.; McIntosh, W. C.

    2011-12-01

    Cenozoic alkaline magmatism in the northwestern Ross Sea (NWRS) region has been recently expanded to include numerous volcanic seamounts on the continental shelf and hundreds more located within the oceanic Adare Basin [1]. The seamounts are Pliocene in age and petrogenetically akin to volcanism on land in the West Antarctic rift system. In general, trace element and Sr-Nd-Pb isotopic data resemble those from ocean islands with HIMU affinity. Apart from the well studied Cameroon volcanic line in West Africa, the NWRS is a unique setting for comparing contemporary alkaline volcanism bridging the transition from oceanic to thinned continental lithosphere adjacent to the thick East Antarctic craton. The geochemistry of NWRS basalts, extending to the northeast from the Mariner Glacier to the Adare Peninsula and into the Adare Basin (~168°E 73°S to ~173°E 70°S), shows a remarkable orderly increase in degree of silica-undersaturation, P2O5, Nb, Zr, Sr contents and La/Yb, Nb/Y, 143Nd/144Nd and 206Pb/204Pb ratios, coupled with a decrease in Ba/La and 87Sr/86Sr ratios, suggesting they were generated from a common heterogeneous mantle source at progressively smaller melt fractions from land to sea. Geochemical variations coincide with northward age propagation in magmatism and southward increase in rifting since the middle Miocene [2]. We propose that the HIMU-like signature in both continental and oceanic sectors is derived from metasomatized lithosphere, whereby the most easily fusible components contribute to the smaller degree melts in greater proportions ocean-ward. Melting may have been triggered by influx of warm asthenosphere initially beneath the continent and then northward by edge-driven convection and channelized by focused extension [3] into the Adare Basin where the metasomatized source is more dispersed. [1] Panter & Castillo (2008) USGS Open-File Report 2007-1047, 069. [2] Granot et al. (2010) Geochem. Geophys. Geosyst. 11(8). [3] Huerta & Harry (2007

  2. Linking the Late Cretaceous to Paleogene Pacific plate and the Atlantic bordering continents using plate circuits and paleomagnetic data

    NASA Astrophysics Data System (ADS)

    Doubrovine, Pavel V.; Tarduno, John A.

    2008-07-01

    Late Cretaceous to Paleogene paleomagnetic data from the Pacific plate (the Emperor Seamounts) can be compared with data from the Atlantic bordering continents through the use of plate circuit reconstructions. Here we summarize the uncertainties in all data sets and present formal tests. We report agreement between Late Cretaceous Pacific paleomagnetic data and predictions based on the estimates of non-Pacific pole positions from synthetic apparent polar wander paths. This congruency points to the veracity of the plate circuits and the accuracy of the paleomagnetic estimates. In contrast to the agreement seen for the Late Cretaceous, small discrepancies are observed in the comparisons of the Pacific Paleogene data and predictions from synthetic apparent polar wander paths. Such a disparity in a younger time interval is unexpected, given the agreement of the Late Cretaceous data. The possibility that minor, temporally variable nondipole field components contribute to the discrepancy cannot be completely discounted. However, an alternative and more straightforward explanation is suggested by further comparisons of the mean non-Pacific paleomagnetic data and the highest-quality poles that contribute to the means. In particular, we note that (1) the Pacific Paleogene data are in full agreement with coeval poles from North America meeting strict reliability criteria and (2) the non-Pacific Paleogene poles of synthetic apparent polar wander paths are dominated by results from the North Atlantic Igneous Province (NAIP), but taken as a whole, the NAIP data fail a paleomagnetic reversal test. Hence, minor discrepancies between Paleocene paleomagnetic data from the Pacific and Atlantic hemispheres may point to limitations of the latter, which incorporate a relatively large number of older, lower-quality data. These findings call for renewed data collections utilizing comprehensive rock magnetic and paleomagnetic (demagnetization) procedures to improve resolution of Paleocene

  3. Transfer of atmospheric boron from the oceans to the continents: An investigation using precipitation waters and epiphytic lichens

    NASA Astrophysics Data System (ADS)

    Rose, E. F.; Carignan, J.; Chaussidon, M.

    2000-11-01

    large range of B concentrations measured in single rain events by selective removal of one of the two B components. In this model, unfractionated marine air masses can reach the continents with very variable B concentrations, between ˜0.2 and ˜20 μg/L.

  4. Cretaceous seamounts along the continent ocean transition of the Iberian margin: U Pb ages and Pb Sr Hf isotopes

    NASA Astrophysics Data System (ADS)

    Merle, Renaud; Schärer, Urs; Girardeau, Jacques; Cornen, Guy

    2006-10-01

    To elucidate the age and origin of seamounts in the eastern North Atlantic, 54 titanite and 10 zircon fractions were dated by the U-Pb chronometer, and initial Pb, Sr, and Hf isotope ratios were measured in feldspars and zircon, respectively. Rocks analyzed are essentially trachy-andesites and trachytes dredged during the "Tore Madeira" cruise of the Atalante in 2001. The ages reveal different pulses of alkaline magmatism occurring at 104.4 ± 1.4 (2 σ) Ma and 102.8 ± 0.7 Ma on the Sponge Bob seamount, at 96.3 ± 1.0 Ma on Ashton seamount, at 92.3 ± 3.8 Ma on the Gago Coutinho seamount, at 89.3 ± 2.3 Ma and 86.5 ± 3.4 Ma on the Jo Sister volcanic complex, and at 88.3 ± 3.3 Ma, 88.2 ± 3.9, and 80.5 ± 0.9 Ma on the Tore locality. No space-time correlation is observed for alkaline volcanism in the northern section of the Tore-Madeira Rise, which occurred 20-30 m.y. after opening of the eastern North Atlantic. Initial isotope signatures are: 19.139-19.620 for 206Pb/ 204Pb, 15.544-15.828 for 207Pb/ 204Pb, 38.750-39.936 for 208Pb/ 204Pb, 0.70231-0.70340 for 87Sr/ 86Sr, and +6.9 to +12.9 for initial epsilon Hf. These signatures are different from Atlantic MORB, the Madeira Archipelago and the Azores, but they lie in the field of worldwide OIB. The Cretaceous seamounts therefore seem to be generated by melts from a OIB-type source that interact with continental lithospheric mantle lying formerly beneath Iberia and presently within the ocean-continent transition zone. Inheritance in zircon and high 207Pb of initial Pb substantiate the presence of very minor amounts of continental material in the lithospheric mantle. A long-lived thermal anomaly is the most plausible explanation for alkaline magmatism since 104 Ma and it could well be that the same anomaly is still the driving force for tertiary and quaternary alkaline magmatism in the eastern North Atlantic region. This hypothesis is agreement with the plate-tectonic position of the region since Cretaceous time

  5. Coupling of a regional atmospheric model (RegCM3) and a regional oceanic model (FVCOM) over the maritime continent

    NASA Astrophysics Data System (ADS)

    Wei, Jun; Malanotte-Rizzoli, Paola; Eltahir, Elfatih A. B.; Xue, Pengfei; Xu, Danya

    2014-09-01

    Climatological high resolution coupled climate model simulations for the maritime continent have been carried out using the regional climate model (RegCM) version 3 and the finite volume coastal ocean model (FVCOM) specifically designed to resolve regions characterized by complex geometry and bathymetry. The RegCM3 boundary forcing is provided by the EMCWF-ERA40 re-analysis. FVCOM is embedded in the Global MITgcm which provides boundary forcing. The domain of the coupled regional model covers the entire South China Sea with its through-flow, the entire Indonesian archipelago with the Indonesian through-flow (ITF) and includes a large region in the western Pacific and eastern Indian oceans. The coupled model is able to provide stable and realistic climatological simulations for a specific decade of atmospheric-oceanic variables without flux correction. The major focus of this work is on oceanic properties. First, the coupled simulation is assessed against ocean-only simulations carried out under two different sets of air-sea heat fluxes. The first set, provided by the MITgcm, is proved to be grossly deficient as the heat fluxes are evaluated by a two-dimensional, zonally averaged atmosphere and the simulated SST have anomalous cold biases. Hence the MITgcm fluxes are discarded. The second set, the NCEP re-analysis heat fluxes, produces a climatological evolution of the SST with an average cold bias of ~-0.8 °C. The coupling eliminates the cold bias and the coupled SST evolution is in excellent agreement with the analogous evolution in the SODA re-analysis data. The detailed comparison of oceanic circulation properties with the International Nusantara Stratification and Transport observations shows that the coupled simulation produces the best estimate of the total ITF transport through the Makassar strait while the transports of three ocean-only simulations are all underestimated. The annual cycle of the transport is also very well reproduced. The coupling also

  6. Lithosphere and Asthenosphere Properties beneath Oceans and Continents and their Relationship with Domains of Partial Melt Stability in the Mantle

    NASA Astrophysics Data System (ADS)

    Dasgupta, R.

    2014-12-01

    The depth of the lithosphere-asthenosphere boundary (LAB) and the change in properties across the lithosphere, asthenosphere, and LAB in various tectonic settings are captured in a variety of geophysical data, including seismic velocities and electrical conductivity. A sharp drop in shear wave velocity and increase in electrical conductivity can potentially be caused by the appearance of partial melt at or below the LAB but the chemical and dynamic stability of partial melt across lithosphere and at LAB remain debated. Here I apply the recent models of mantle melting in the presence of water and carbon [1, 2] to evaluate the domains of stability of partial melt both beneath continents and oceans. The model allows prediction of the possible presence, the fraction, and composition of partial melt as a function of depth, bulk C and H2O content, and fO2 [3] in various geologic/tectonic settings. The results show that while a hydrous, carbonated melt is stable only beneath LAB and in the asthenospheric mantle beneath oceans, continental mantle can contain a carbonate-rich melt within the lithosphere. For geotherms corresponding to surface heat flux (SHF) of 40-50 mW m-2, which also match P-T estimates beneath cratons based on thermo-barometry of peridotite xenoliths [4], the solidus of fertile peridotite with trace amount of CO2 and H2O is crossed at depths as shallow as 80-120 km [5]. If elevated geotherms of the Proterozoic and Phanerozoic terrains are applied, carbonatitic melt becomes stable somewhat shallower. These depths are similar to those argued for a mid-lithospheric discontinuity (MLD) where a negative velocity gradient has been detected much shallower than the proposed depth of LAB in many places. With a drop in oxygen fugacity with depth, a freezing of carbonatitic melt may be expected at intermediate depths (~150-200 km). At 200-250 km a hydrous, carbonated silicate melt may reappear owing to the interplay of fO2 and freezing point depression effect of CO

  7. Modulation of Cenozoic climate by weathering of large igneous provinces on continents drifting through equatorial humid belt

    NASA Astrophysics Data System (ADS)

    Muttoni, G.; Kent, D. V.

    2011-12-01

    The small reservoir of CO2 in the atmosphere (pCO2) that modulates climate through the greenhouse effect is a delicate balance between large fluxes of sources and sinks. The major long-term source of CO2 is global degassing from sea-floor spreading, subduction, hotspot activity, and metamorphism; the ultimate sink is through weathering of continental silicates. Most carbon cycle models are driven by changes in the source flux, in particular, variable rates of ocean floor production (and concomitant subduction) but the area/age versus age distribution of the modern ocean is compatible with a steady rate since 180 Ma (Rowley, 2002 GSA Bulletin). We previously suggested (2008 PNAS) that evidence of high pCO2 and warm climates in the Cretaceous-early Cenozoic could be explained by the subduction of Tethyan ocean crust loaded with equatorial carbonate-rich pelagic (more readily subductable) sediments since the onset of India's northward flight at ~120 Ma up until the CO2-producing decarbonation factory slowed down with collision of India and Asia at the Early Eocene Climate Optimum at 50 Ma. At about this time, the India continent and the highly weatherable Deccan Traps drifted into the equatorial humid belt where uptake of CO2 by efficient silicate weathering would further lower the level of pCO2. Continued weathering uptake was influenced by the southerly extrusion of SE Asia in response to the Indian indentor starting at ~40 Ma (Molnar & Tapponnier, 1975 Science) as well as the emplacement of the Ethiopian traps near the Equator at 30 Ma. The ongoing impingement of India into Asia and resultant southerly tectonic extrusion of SE Asia (Replumaz & Tapponnier, 2003 JGR) makes it the dominant new area in the equatorial humid belt. Moreover, SE Asia presently accounts for 25% of CO2 consumption of all basaltic provinces, which account for ~1/3 of the total consumption by continental silicate weathering (Dessert et al., 2003 Chemical Geology) that is within the range of

  8. Measurement of electromagnetic waves in ELF and VLF bands to monitor lightning activity in the Maritime Continent

    NASA Astrophysics Data System (ADS)

    Yamashita, Kozo; Takahashi, Yukihiro; Ohya, Hiroyo; Tsuchiya, Fuminori; Sato, Mitsuteru; Matsumoto, Jun

    2013-04-01

    Data of lightning discharge has been focused on as an effective way for monitoring and nowcasting of thunderstorm activity which causes extreme weather. Spatial distribution of lightning discharge has been used as a proxy of the presence or absence of deep convection. Latest observation shows that there is extremely huge lightning whose scale is more than hundreds times bigger than that of averaged event. This result indicates that lightning observation should be carried out to estimate not only existence but also scale for quantitative evaluation of atmospheric convection. In this study, lightning observation network in the Maritime Continent is introduced. This network is consisted of the sensors which make possible to measure electromagnetic wave radiated from lightning discharges. Observation frequency is 0.1 - 40 kHz for the measurement of magnetic field and 1 - 40 kHz for that of electric field. Sampling frequency is 100 kHz. Waveform of electromagnetic wave is recorded by personal computer. We have already constructed observation stations at Tainan in Taiwan (23.1N, 121.1E), Saraburi in Thailand (14.5N, 101.0E), and Pontianak in Indonesia (0.0N, 109.4E). Furthermore, we plan to install the monitoring system at Los Banos in Philippines (14.18, 121.25E) and Hanoi in Viet Nam. Data obtained by multipoint observation is synchronized by GPS receiver installed at each station. By using data obtained by this network, location and scale of lightning discharge can be estimated. Location of lightning is determined based on time of arrival method. Accuracy of geolocation could be less than 10km. Furthermore, charge moment is evaluated as a scale of each lightning discharge. It is calculated from electromagnetic waveform in ELF range (3-30 kHz). At the presentation, we will show the initial result about geolocation for source of electromagnetic wave and derivation of charge moment value based on the measurement of ELF and VLF sferics.

  9. Implication of vector characteristics of Phlebotomus argentipes in the kala-azar elimination programme in the Indian sub-continent

    PubMed Central

    Chowdhury, Rajib; Kumar, Vijay; Mondal, Dinesh; Das, Murari Lal; Das, Pradeep; Dash, Aditya Prasad

    2016-01-01

    Background Visceral leishmaniasis (VL), also known as kala-azar in the Indian sub-continent (ISC), is a major public health concern in Bangladesh, India, and Nepal, where it is caused by Leishmania donovani transmitted by the sand fly Phlebotomus argentipes. Various ecological parameters including air temperature, rainfall, wind speed, relative humidity, soil moisture, pH, and organic carbon are known to influence the oviposition of female sand flies, as well as the survival and development of larvae. However, more detailed knowledge on vector behavior, such as biting times, breeding places, and preferred hosts are needed to design optimal evidence-based vector control interventions. Methods In order to facilitate rational decisions regarding VL vector control, a systematic review was conducted to identify the prevailing practice and knowledge gaps in relation to vector bionomics and behavior. Search terms included ‘sand fly bionomics’, ‘habitat’, and ‘visceral leishmaniasis/kala-azar vector control’ using the Boolean operator AND to identify the country of interest, namely: Bangladesh, India, and Nepal. Both PubMed and Google search engines were used. Additional unpublished documents in the three countries were also analyzed. Results Information on the life cycle of VL vectors, their breeding behavior, infection rate with L. donovani, feeding behavior, and seasonal variation are useful for designing vector control operations. Unfortunately, none of the studies on the life cycle of P. argentipes was conducted in field settings of the ISC, so the publications from other locations had to be used for determining the duration of life cycle and development from egg to adult. However, information about breeding places, seasonal variation of vector densities, and 47 out of the selected 51 papers are available from the ISC and can be used for intelligent design of control operations. Conclusion Vector control services should undertake routine insecticide

  10. From magma-poor Ocean Continent Transitions to steady state oceanic spreading: the balance between tectonic and magmatic processes

    NASA Astrophysics Data System (ADS)

    Gillard, Morgane; Manatschal, Gianreto; Autin, Julia; Decarlis, Alessandro; Sauter, Daniel

    2016-04-01

    The evolution of magma-poor rifted margins is linked to the development of a transition zone whose basement is neither clearly continental nor oceanic. The development of this Ocean-Continent Transition (OCT) is generally associated to the exhumation of serpentinized mantle along one or several detachment faults. That model is supported by numerous observations (IODP wells, dredges, fossil margins) and by numerical modelling. However, if the initiation of detachment faults in a magma-poor setting tends to be better understood by numerous studies in various area, the transition with the first steady state oceanic crust and the associated processes remain enigmatic and poorly studied. Indeed, this latest stage of evolution appears to be extremely gradual and involves strong interactions between tectonic processes and magmatism. Contrary to the proximal part of the exhumed domain where we can observe magmatic activity linked to the exhumation process (exhumation of gabbros, small amount of basalts above the exhumed mantle), in the most distal part the magmatic system appears to be independent and more active. In particular, we can observe large amounts of extrusive material above a previously exhumed and faulted basement (e.g. Alps, Australia-Antarctica margins). It seems that some faults can play the role of feeder systems for the magma in this area. Magmatic underplating is also important, as suggested by basement uplift and anomalously thick crust (e.g. East Indian margin). It results that the transition with the first steady state oceanic crust is marked by the presence of a hybrid basement, composed by exhumed mantle and magmatic material, whose formation is linked to several tectonic and magmatic events. One could argue that this basement is not clearly different from an oceanic basement. However, we consider that true, steady state oceanic crust only exists, if the entire rock association forming the crust is created during a single event, at a localized

  11. Anomalous Subsidence of the Ocean Continent Transition at Rifted Continental Margins: Observations from the Gulf of Aden

    NASA Astrophysics Data System (ADS)

    Cowie, L.; Kusznir, N. J.

    2011-12-01

    It has been proposed that some continental rifted margins have anomalous early subsidence histories and that at break-up they were elevated at shallower bathymetries than the isostatic response of classical rift models (McKenzie 1978) would predict. The existence of anomalous syn- or early post-breakup subsidence, of this form, would have important implications for our understanding of the geodynamics of continental breakup and sea-floor spreading initiation and important consequences for syn- and post-breakup depositional systems. Possible explanations for anomalous subsidence during continental breakup could include transient effects as the continental geotherm evolves towards an oceanic form, or small scale convection. Lucazeau et al. (2008) have reported anomalously high heat-flows in the ocean continent transition (OCT) of the young rifted margin of the Eastern Gulf of Aden which would have implications for its subsidence history. In order to verify (or otherwise) the proposition of an anomalous early post-breakup subsidence history in the Eastern Gulf of Aden, we have determined anomalous oceanic subsidence using residual depth anomaly (RDA) analysis and have compared lithosphere thinning across the OCT measured using subsidence analysis with continental crustal basement thinning from gravity inversion. Both 3D regional and localised 2D analyses have been carried out. The localised studies focus on published seismic reflection lines (Autin et al, 2010; D'Acremont et al, 2005; Fournier et al, 2007; Leroy et al, 2004; Leroy et al, 2010; Lucazeau et al 2008; Lucazeau et al 2010). RDAs have been calculated by comparing observed and predicted oceanic bathymetries. Regional 3D RDAs for the Gulf of Aden, without a sediment correction, show positive RDAs between 3km and 4km at the rifted margins decreasing to 0.5km at the ocean ridge axis. Localised 2D sediment corrected RDA profiles determined within and adjacent to the OCT of the Eastern Gulf of Aden are also

  12. Nurture Versus Nature: Accounting for the Differences Between the Taiwan and Timor active arc-continent collisions

    NASA Astrophysics Data System (ADS)

    Harris, R. A.

    2011-12-01

    The active Banda arc/continent collision of the Timor region provides many important contrasts to what is observed in Taiwan, which is mostly a function of differences in the nature of the subducting plate. One of the most important differences is the thermal state of the respective continental margins: 30 Ma China passive margin versus 160 Ma NW Australian continental margin. The subduction of the cold and strong NW Australian passive margin beneath the Banda trench provides many new constraints for resolving longstanding issues about the formative stages of collision and accretion of continental crust. Some of these issues include evidence for slab rollback and subduction erosion, deep continental subduction, emplacement or demise of forearc basement, relative amounts of uplift from crustal vs. lithospheric processes, influence of inherited structure, partitioning of strain away from the thrust front, extent of mélange development, metamorphic conditions and exhumation mechanisms, continental contamination and accretion of volcanic arcs, does the slab tear, and does subduction polarity reverse? Most of these issues link to the profound control of lower plate crustal heterogeneity, thermal state and inherited structure. The thermomechanical characteristics of subducting an old continental margin allow for extensive underthrusting of lower plate cover units beneath the forearc and emplacement and uplift of extensive nappes of forearc basement. It also promotes subduction of continental crust to deep enough levels to experience high pressure metamorphism (not found in Taiwan) and extensive contamination of the volcanic arc. Seismic tomography confirms subduction of continental lithosphere beneath the Banda Arc to at least 400 km with no evidence for slab tear. Slab rollback during this process results in massive subduction erosion and extension of the upper plate. Other differences in the nature of the subducting plates in Taiwan in Timor are differences in the

  13. The Second "Ring of Towers": Over-sampling the Mid Continent Intensive region CO2 mixing ratio?

    NASA Astrophysics Data System (ADS)

    Richardson, S.; Miles, N.; Davis, K.; Crosson, E.; Denning, S.; Zupanksi, D.; Uliasz, M.

    2007-12-01

    A central barrier preventing the scientific community from understanding the carbon balance of the continent is methodological; it is technically difficult to bridge the gap in spatial scales that exists between the detailed understanding of ecological processes that can be gathered via intensive local field study, and the overarching but mechanistically poor understanding of the global carbon cycle that is gained by analyzing the atmospheric CO2 budget. The NACP's Midcontinental Intensive (MCI) study seeks to bridge this gap by conducting a rigorous methodological test of our ability to measure the terrestrial carbon balance of the upper Midwest. A critical need in bridging this gap is increased data density. A primary goal of the project is to increase the regional atmospheric CO2 data density so that 1) atmospheric inversions can derive well-constrained regional ecosystem carbon flux estimates and 2) the trade off between data density and accuracy of the flux estimates can be determined quantitatively using field observations, thus providing guidance to future observational network designs. Our work adds a regional network of five communications-tower based atmospheric CO2 observations to the planned long-term atmospheric CO2 observing network (tall towers, flux towers and aircraft profiles) in the midcontinent intensive region. Measurements began in April-June 2007, If the measurements are shown to be spatially dense enough to over sample the CO2 mixing ratio, the experiment will provide an upper bounds on the density of measurements required to produce the most accurate flux possible with current atmospheric inversions. The five sites for "Ring 2" and deployment dates are Centerville, IA (Apr 07), Round Lake, MN (May 07), Kewanee, IL (Apr 07), Mead, NE (Apr 07), Galesville, WI (June 07). Two heights are sampled at each tower (30 m AGL and between 110 and 140 m AGL). More details are available at www.ring2.psu.edu. In addition, two systems in PSU's network of

  14. Crustal Thickness Mapping of the Rifted Margin Ocean-Continent Transition using Satellite Gravity Inversion Incorporating a Lithosphere Thermal Correction

    NASA Astrophysics Data System (ADS)

    Hurst, N. W.; Kusznir, N. J.

    2005-05-01

    A new method of inverting satellite gravity at rifted continental margins to give crustal thickness, incorporating a lithosphere thermal correction, has been developed which does not use a priori information about the location of the ocean-continent transition (OCT) and provides an independent prediction of OCT location. Satellite derived gravity anomaly data (Sandwell and Smith 1997) and bathymetry data (Gebco 2003) are used to derive the mantle residual gravity anomaly which is inverted in 3D in the spectral domain to give Moho depth. Oceanic lithosphere and stretched continental margin lithosphere produce a large negative residual thermal gravity anomaly (up to -380 mgal), which must be corrected for in order to determine Moho depth. This thermal gravity correction may be determined for oceanic lithosphere using oceanic isochron data, and for the thinned continental margin lithosphere using margin rift age and beta stretching estimates iteratively derived from crustal basement thickness determined from the gravity inversion. The gravity inversion using the thermal gravity correction predicts oceanic crustal thicknesses consistent with seismic observations, while that without the thermal correction predicts much too great oceanic crustal thicknesses. Predicted Moho depth and crustal thinning across the Hatton and Faroes rifted margins, using the gravity inversion with embedded thermal correction, compare well with those produced by wide-angle seismology. A new gravity inversion method has been developed in which no isochrons are used to define the thermal gravity correction. The new method assumes all lithosphere to be initially continental and a uniform lithosphere stretching age is used corresponding to the time of continental breakup. The thinning factor produced by the gravity inversion is used to predict the thickness of oceanic crust. This new modified form of gravity inversion with embedded thermal correction provides an improved estimate of rifted

  15. The helium flux from the continents and ubiquity of low-3He/4He recycled crust and lithosphere

    NASA Astrophysics Data System (ADS)

    Day, James M. D.; Barry, Peter H.; Hilton, David R.; Burgess, Ray; Pearson, D. Graham; Taylor, Lawrence A.

    2015-03-01

    geological timescales (>0.1 Ga), and that U and Th contents vary between cratonic lithosphere and non-cratonic lithosphere, calculations yield a 3He flux of 0.25-2.2 atoms/s/cm2 for the continental lithospheric mantle. These estimates differ by a factor of ten from non-cratonic lithospheric mantle and are closer to the observed 3He flux from the continents (<1 atoms/s/cm2). Pyroxenites and eclogites from the continental regions are all characterized by 3He/4He (0.03-5.6 RA) less than the depleted upper mantle, and relatively high U and Th contents. Together with oceanic and continental lithospheric peridotites, these materials represent reservoirs with low time-integrated 3He/(U + Th) in the mantle. Pyroxenites and eclogites are also characterized by higher Fe/Mg, more radiogenic Os-Pb isotope compositions, and more variable δ18O values (∼3‰ to 7‰), compared with peridotitic mantle. These xenoliths are widely interpreted to be the metamorphic/metasomatic equivalents of recycled oceanic crustal protoliths. The low-3He/4He values of these reservoirs and their distinctive compositions make them probable end-members to explain the compositions of some low-3He/4He OIB, and provide an explanation for the low-3He/4He measured in most HIMU lavas. Continental lithospheric mantle and recycled oceanic crust protoliths are not reservoirs for high-3He/4He and so alternative, volumetrically significant, He-rich reservoirs, such as less-degassed (lower?) mantle, are required to explain high-3He/4He signatures measured in some intraplate lavas. Recycling of oceanic crust represents a fundamental process for the generation of radiogenic noble gases in the mantle, and can therefore be used effectively as tracers for volatile recycling.

  16. High-dose OxyContin to treat pain associated with bone metastasis in patients with small-cell lung cancer: a case study report

    PubMed Central

    Zhou, Tao; Zhang, Xia; Dong, Yan; Zhuang, Feifei; Jiang, Fengquan; Yu, Jinming; Zhang, Bin

    2016-01-01

    Pain management is an important topic that has received extensive attention from clinical practitioners. Nearly all patients with malignant tumors suffer pain at the advanced stage of their disease. Oxycodone is a first-line choice for treating moderate-to-severe cancer-related pain, and OxyContin, a controlled-release oxycodone hydrochloride tablet, is internationally recognized as a safe and effective opioid analgesic. OxyContin has the characteristics of both immediate release and sustained release, with a time to onset and peak similar to those of immediate-release morphine. It acts on both μ and κ receptors and has been shown to be effective in treating different types of pain, especially neuropathic pain, theoretically without a dose cap. However, the dose is limited in clinical applications due to various factors that are likely to affect its analgesic effect and reduce patient quality of life. Cooperation with a patient’s family members is required during the treatment of cancer pain. Chronic cancer pain has a long disease course, which could easily cause complex psychological symptoms due to their important role in the pain experience. Pain is controllable, and patients have a right to not experience pain. An optimal living state can be achieved through collaboration between physicians and patients. Rational personalized treatment of cancer pain can improve patient quality of life, relieve pain, and help prolong patient survival. This article reports the treatment procedure and adverse reactions in a patient who was treated with high-dose OxyContin, with the aim of providing a reference for other clinical practitioners. PMID:26855563

  17. Cell concentration of bacteria in the Asian continent outflow under different weather conditions observed at southwestern Japan between 2010 and 2013

    NASA Astrophysics Data System (ADS)

    Zhang, D.; Murata, K.

    2013-12-01

    Widespread dispersal of microorganisms in the air is considered to be particularly important for ice cloud formation in elevated levels. However, very few quantitative data on their concentration are available. The purpose of the study is to figure out the manner by which bacteria are transported and gain the bacteria's concentration and viability in the Northern Hemisphere westerly winds at the downstream areas of the Asian continent. Viable and non-viable airborne bacteria were measured with fluorescence microscopy coupled with LIVE/DEAD BacLight Bacterial Viability Kits under various weather conditions at Kumamoto, a coastal city in southwestern Japan. The concentration in thermodynamically different air parcels was in the similar order, hundreds of thousand cells per cubic meter, but different ranges. No correlation was found between the concentration and coarse aerosol particles (diameter>1.0 μm) in prefrontal air and anticyclone air. In contrast, the concentration correlated closely with coarse particles in the postfrontal air and the concentration increased proportionally to coarse particle concentrations by 1 ~ 2 orders in the presence of Asian dust. Bacterial viability was around 70% on average in the different kinds of air parcels. However, the viability in fast-moving postfrontal air was smaller. In summary, air parcels following strong cold fronts in the westerly wind flow constantly and efficiently convey airborne bacteria, characterized by coarse particle-correlated high concentration and low viability, from the Asian continent while the bacteria in slowly-moving anticyclone and prefrontal air, characterized by low concentration and high viability, are more likely a mixture of bacteria from the Asian continent and the local areas.

  18. From Archean to Present - Structure and Evolution of the North American Mid-Continent through the Lens of EarthScope Magnetotelluric Data

    NASA Astrophysics Data System (ADS)

    Bedrosian, P.

    2015-12-01

    The North American mid-continent presents a window into craton growth and stabilization as well as a 1.1 Ga rifting event that nearly tore Laurentia apart. Unique to this region is the preservation of this tectonic collage, largely unmodified by subsequent tectonic events, which permits examination of if and how such events are preserved in the continental lithosphere. I will present a three-dimensional lithospheric-scale resistivity model derived from EarthScope magnetotelluric data. I will discuss details of the resistivity model in relation to lithospheric sutures, defined primarily from aeromagnetic and geochronologic data, which record the southward growth of the Laurentian margin in the Precambrian. I will examine in detail the resistivity signature of the 1.1 Ga Mid-Continent Rift System as relates to rift geometry, extent, and segmentation. I further speculate that axial drainage along the southwest rift arm created an unrecognized expanse of (concealed) Precambrian deltaic deposits in Kansas akin to the Rio Grande delta that today drains multiple sub-basins within the Rio Grande Rift. The resistivity model also reveals the distribution of highly conductive Paleoproterozoic metasediments in Minnesota, Michigan, and Wisconsin. The high conductivity is attributed to metallic sulfides and in some cases graphite. The former is considered a potential source of sulfur for multiple types of mineral deposits found in the region. Finally, I consider the imprint left within the mantle following the 1.1 Ga rifting event. Throughout the mid-continent, variations in lithospheric mantle conductivity are revealed, most likely reflecting variations in hydration (depleted versus metasomatized mantle). The spatial pattern of conductivity variations bears little resemblance to past tectonic events or to the direction of North American absolute plate motion.

  19. Interannual variations in atmospheric mass over liquid water oceans, continents, and sea-ice-covered arctic regions and their possible impacts on the boreal winter climate

    NASA Astrophysics Data System (ADS)

    Guan, Zhaoyong; Zhang, Qian; Li, Minggang

    2015-12-01

    Using reanalysis data from National Centers for Environmental Prediction/National Center for Atmospheric Research, ERA-interim, and Hadley Centre Sea Ice and Sea Surface Temperature for the period of 1979-2012, the variations in atmospheric mass (AM) over liquid water oceans, continents, and sea-ice-covered Arctic regions during boreal winter are investigated. It is found that AM may migrate in a compensatory manner among these three types of surfaces on interannual time scales. There are two pairs of strong antiphase relations. One lies in a zonal orientation between the Eurasian continent and the midlatitude Pacific (referred to as Eurasian continent/Pacific antiphase relation) and exhibits a teleconnection pattern characterized by two strong correlation centers, one over Eurasia and one over the North Pacific. The other antiphase AM relation, referred to as ocean/ice-covered Arctic antiphase relation (OIAR), exhibits a meridional orientation between the ice-covered Arctic and liquid water oceans, including the Atlantic and Pacific. In the context of the OIAR, two teleconnection patterns are observed. One features three strong correlation centers, one each over the Mediterranean, Arctic, and North Pacific, and corresponds to AM fluctuations over liquid water oceans. The other is characterized by three strong correlation centers over the Mediterranean, the Arctic, and East Asia, and corresponds to AM fluctuations over the ice-covered Arctic. These teleconnections are the results of thermal contrasts among the three types of surfaces. Rossby waves and vertical circulations play important roles in the formation of these teleconnections. Interestingly, these teleconnections may have significant and widespread influences on the winter climate in the Northern Hemisphere, especially in regions near the Mediterranean, the northern Eurasia, parts of North America, and East Asia.

  20. Gondwana to Asia: Plate tectonics, paleogeography and the biological connectivity of the Indian sub-continent from the Middle Jurassic through latest Eocene (166 35 Ma)

    NASA Astrophysics Data System (ADS)

    Ali, Jason R.; Aitchison, Jonathan C.

    2008-06-01

    Using the most up-to-the-date information available, we present a considerably revised plate tectonic and paleogeographic model for the Indian Ocean bordering continents, from Gondwana's Middle Jurassic break-up through to India's collision with Asia in the middle Cenozoic. The landmass framework is then used to explore the sometimes complex and occasionally counter-intuitive patterns that have been observed in the fossil and extant biological records of India, Madagascar, Africa and eastern Eurasia, as well those of the more distal continents. Although the paleogeographic model confirms the traditional view that India became progressively more isolated from the major landmasses during the Cretaceous and Paleocene, it is likely that at various times minor physiographic features (principally ocean islands) provided causeways and/or stepping-stone trails along which land animals could have migrated to/from the sub-continent. Aside from a likely link (albeit broken by several marine gaps) to Africa for much of this time (it is notable, that the present-day/recent biota of Madagascar indicates that the ancestors of five land-mammal orders, plus bats, crossed the > 400-km-wide Mozambique Channel at different times in the Cenozoic), it is possible that the Kerguelen Plateau connected India and Australia-Antarctica in the mid-Cretaceous (approximately 115-90 Ma). Later, the Seychelles-Mascarene Plateau and nearby elevated sea-floor areas could have allowed faunas to pass between southern India and Madagascar in the Late Cretaceous, from around 85-65 Ma, with an early Cenozoic extension to this path forming as a result of the Reunion hot-spot trace islands growing on the ocean floor to the SSW of India. The modelling also suggests that India's northward passage towards Asia, with eventual collision at 35 Ma, involved the NE corner of the sub-continent making a glancing contact with Sumatra, followed by Burma from ~ 57 Ma (late Paleocene) onwards, a scenario which is

  1. Gastroenterology and urology devices; effective date of requirement for premarket approval of the implanted mechanical/hydraulic urinary continence device. Food and Drug Administration, HHS. Final rule.

    PubMed

    2000-09-26

    The Food and Drug Administration (FDA) is issuing a final rule to require the filing of a premarket approval application (PMA) or a notice of completion of a product development protocol (PDP) for the implanted mechanical/hydraulic urinary continence device, a generic type of medical device intended for the treatment of urinary incontinence. This action is being taken under the Federal Food, Drug, and Cosmetic Act (the act), as amended by the Medical Device Amendments of 1976 (the amendments), the Safe Medical Devices Act of 1990 (the SMDA), and the Food and Drug Administration Modernization Act of 1997. PMID:11503643

  2. Structural evolution from Paleogene extension to Latest Miocene-Recent arc-continent collision offshore Taiwan: comparison with on land geology

    NASA Astrophysics Data System (ADS)

    Huang, Chi-Yue; Xia, Kanyuan; Yuan, Peter B.; Chen, Pu-Gang

    2001-08-01

    Marine structures observed in seismic profiles across the NE South China Sea-Taiwan Strait-Luzon Arc region show that they are comparable to those observed onshore Taiwan. The Hanjiang Depression and Dongsha Uplift off the SE China coast extend to the Penghu Basin and Penghu Platform, respectively, in the Taiwan Strait, while the Tainan Basin in the south of Penghu Platform is connected to the Chaoshan Depression south of the Dongsha Uplift. The Hanjiang Depression and the Penghu Basin are composed of Paleogene syn-rift sequences on the Mesozoic basement and are unconformably overlain by Neogene post-rift strata. Similar successions are found underneath the coastal plain or have been thrust up as a fold-and-thrust belt bordering the Peikang Basement High onshore central Taiwan. East of the Manila Trench, off southwestern Taiwan, parts of the Tainan Basin are thrust into the submarine syn-collision accretionary wedge (the fold-and-thrust Kaoping Slope) in the initial arc-continent collision zone. They have also been exposed in the fold-and-thrust Western Foothills south of the Peikang Basement High in southern Taiwan during an advanced stage of arc-continent collision since the Late Pliocene. Further east, the pre-collision accretionary wedge (the Hengchun Ridge) shoals northward to the Hengchun Peninsula, with Late Miocene turbidites unconformably overlain by Plio-Pleistocene shallow-marine slope basin sequences. In the arc domain, east of the arc-prism boundary fault, the western forearc sequences in the North Luzon Trough are deformed. Two normal-faulted intra-arc basins occur on the eastern part of the Lanhsu Island in the Luzon Arc. The scenario of the deformed forearc sequences and the development of the two intra-arc basins in the initial arc-continent collision zone are analogous to the Lichi Mélange-Taiyuan Basin and the intra-arc basins in the southern Coastal Range, eastern Taiwan. Additionally, the lateral change in the marine structure from the passive

  3. The (146,147)Sm-(142,143)Nd systematics of early terrestrial differentiation and the lost continents of the early Earth

    NASA Technical Reports Server (NTRS)

    Harper, Charles L., Jr.; Jacobsen, Stein B.

    1992-01-01

    The very early history of the Earth has been one of the great enduring puzzles in the history of geology. We report evidence which clearly can be described as a vestige of a beginning, because the evidence that we report cannot be interpreted in any other way except as a geochemical signal of processes active in the very early history of the Earth. The evidence itself is a very small anomaly in the abundance of SM-146. The primary aims of this study were to: (1) verify the existence of the 'lost continents' of the Hadean era; and (2) determine their mean age.

  4. Possible late middle Ordovician organic carbon isotope excursion: evidence from Ordovician oils and hydrocarbon source rocks, Mid-Continent and east-central United States

    SciTech Connect

    Hatch, J.R.; Jacobson, S.R.; Witzke, B.J.; Risatti, J.B.; Anders, D.E.; Watney, W.L.; Newell, K.D.; Vuletich, A.K.

    1987-11-01

    A possible coeval excursion in organic-matter delta/sup 13/C is recognized in different late Middle Ordovician lithologic facies over a distance of 480 mi (770 km), perhaps 930 mi (1500 km), in the Mid-Continent and east-central US. The large variability in the carbon isotope compositions of Ordovician oils from the Mid-Continent and east-central US is a direct result of the variable carbon isotope composition of organic matter in the Middle Ordovician hydrocarbon source rocks. The excursion in organic-matter delta/sup 13/C in late Middle Ordovician rocks may reflect significantly increased organic matter productivity and/or preservation. The excursion is not directly related to maceral composition of the organic matter. Limited dissolved CO/sub 2/ availability, possibly a result of continued high organic matter productivity, and limited circulation in the Middle Ordovician seas may have increased the size of the excursion in organic matter delta/sup 13/C. 5 figures, 4 tables.

  5. New model of succession of Middle and Late Pennsylvanian fossil communities in north Texas, Mid-Continent, and Appalachians with implications on black shale controversy

    SciTech Connect

    Boardman, D.R. II; Yancey, T.E.; Mapes, R.H.; Malinky, J.M.

    1983-03-01

    A new model for the succession of Pennsylvanian fossil communities, preserved in cyclothems, is proposed on the basis of more than 200 fossil localities in the Mid-Continent, Appalachians, and north Texas. Early models for Mid-Continent cyclothems placed the black shales in shallow water, with maximum transgression at the fusulinid-bearing zone in the overlying limestone. The most recent model proposed that the black phosphatic shales, which commonly occur between two subtidal carbonates, are widespread and laterally continuous over great distances and represent maximum transgression. The black phosphatic shales contain: ammonoids; inarticulate brachiopods; radiolarians; conularids; shark material and abundant and diverse conodonts. The black shales grade vertically and laterally into dark gray-black shales which contain many of the same pelagic and epipelagic forms found in the phosphatic black shales. This facies contains the deepest water benthic community. Most of these forms are immature, pyritized, and generally are preserved as molds. The dark gray-black facies grades into a medium gray shale facies which contains a mature molluscan fauna. The medium gray shale grades into a lighter gray facies, which is dominated by brachiopods, crinoids, and corals, with occasional bivalves and gastropods. (These facies are interpreted as being a moderate to shallow depth shelf community). The brachiopid-crinoid community is succeeded by shallow water communities which may have occupied shoreline, lagoonal, bay, interdeltaic, or shallow prodeltaic environments.

  6. Analysis of Lake Baikal's phytoplankton and fluvial input dynamics using SeaWiFS satellite data within the Scope of the Paleoclimate Project CONTINENT

    NASA Astrophysics Data System (ADS)

    Heim, B.; Oberhaensli, H.; Kaufmann, H.

    2003-04-01

    Multispectral ocean colour satellite data provide a new tool for spatial and temporal limnological data overview. The Ulaan Baatar (Mongolia) HRPT (high resolution picture transmission) station provides the paleoclimate EC-Project CONTINENT "High Resolution CONTINENTal Paleoclimate Record in Lake Baikal (Siberia, Russia)" with daily SeaWiFS data covering the area of south-eastern Siberia. After a SeaWiFS data processing chain with radiometric and atmospheric correction, we use the water leaving reflectances to gain information on phytoplankton and suspended sediment whose dynamics are a response to the present climate forcing. During the CONTINENT Summer cruises in 2001 and 2002, we were able to verify the spectral analysis of SeaWiFS satellite data with a high quality calibration/validation ground truth data set (field spectrometer and fluorometer measurement activities simultaneously to water sampling activities for pigment and suspended matter SPM and DOC analysis and algae counting). The fluviatil input into Lake Baikal is visible in the SeaWiFS data due to its higher loads of suspended matter, further particularly due to the presence of coloured dissolved organic matter (cDOM). These coloured fraction of DOM (mainly humic acids) originate from the bog areas and swampy basins within the Lake Baikal watershed. The so called yellow substances react optically with a strong absorption in the blue spectral bands of SeaWiFS and are therefore ideal tracers for the river input even over long distances from the river inflow. The phytoplankton main pigment chlorophyll-a is made visible by its absorption band in the blue which results in a green reflectance peak. Additional pigment groups (carotinoids, phycobilins) differentiate the spectral shape of the water leaving reflectance depending on the respective main phytoplankton composition. On satellite images obtained in late Summer, we can differentiate between diatom and cyanobacteria-picoplankton dominated surface water

  7. Visceral leishmaniasis on the Indian sub-continent: a multi-centre study of the costs of three interventions for the control of the sandfly vector, Phlebotomus argentipes.

    PubMed

    Das, M; Banjara, M; Chowdhury, R; Kumar, V; Rijal, S; Joshi, A; Akhter, S; Das, P; Kroeger, A

    2008-12-01

    The sandflies that transmit the parasites causing human visceral leishmaniasis (VL) can be controlled by several methods, including indoor residual spraying (IRS), the use of long-lasting insecticidal nets (LLIN) and ecological vector management (EVM). The financial costs of each of these three methods of sandfly control have recently been assessed and compared, in a multi-centre study based on the Indian sub-continent. In each of the four study sites (two in Nepal and one each in India and Bangladesh), 24 neighbourhoods were randomly selected in districts with high incidences of VL. The costs of the three interventions were then prospectively assessed in each study neighbourhood, in the local currency, and then converted to U.S. dollars at the prevailing exchange rate in the country concerned. The costs of IRS, which ranged from U.S.$2.4-11.7 (mean = U.S.$5.9) per household-year, were greater than those of LLIN (U.S.$3.5-5.1/household-year, with a mean of U. S.$4.5) but less than those of EVM (U. S.$5.0- 14.0/household-year, with a mean of U.S.$8.7). These results indicate that LLIN and IRS may be the cheaper options for the control of sandflies on the Indian sub-continent, and that EVM should perhaps only be taken up as a complimentary and voluntary method. Various combinations of these interventions (based on country-specific social and economic factors) may, however, be the best and most cost-effective choice. PMID:19000390

  8. Arc-continent collision and the formation of continental crust: A new geochemical and isotopic record from the Ordovician Tyrone Igneous Complex, Ireland

    USGS Publications Warehouse

    Draut, Amy E.; Clift, Peter D.; Amato, Jeffrey M.; Blusztajn, Jerzy; Schouten, Hans

    2009-01-01

    Collisions between oceanic island-arc terranes and passive continental margins are thought to have been important in the formation of continental crust throughout much of Earth's history. Magmatic evolution during this stage of the plate-tectonic cycle is evident in several areas of the Ordovician Grampian-Taconic orogen, as we demonstrate in the first detailed geochemical study of the Tyrone Igneous Complex, Ireland. New U-Pb zircon dating yields ages of 493 2 Ma from a primitive mafic intrusion, indicating intra-oceanic subduction in Tremadoc time, and 475 10 Ma from a light rare earth element (LREE)-enriched tonalite intrusion that incorporated Laurentian continental material by early Arenig time (Early Ordovician, Stage 2) during arc-continent collision. Notably, LREE enrichment in volcanism and silicic intrusions of the Tyrone Igneous Complex exceeds that of average Dalradian (Laurentian) continental material that would have been thrust under the colliding forearc and potentially recycled into arc magmatism. This implies that crystal fractionation, in addition to magmatic mixing and assimilation, was important to the formation of new crust in the Grampian-Taconic orogeny. Because similar super-enrichment of orogenic melts occurred elsewhere in the Caledonides in the British Isles and Newfoundland, the addition of new, highly enriched melt to this accreted arc terrane was apparently widespread spatially and temporally. Such super-enrichment of magmatism, especially if accompanied by loss of corresponding lower crustal residues, supports the theory that arc-continent collision plays an important role in altering bulk crustal composition toward typical values for ancient continental crust. ?? 2009 Geological Society of London.

  9. Continental hyperextension, mantle exhumation and thin oceanic crust at the continent-ocean transition, West Iberia: new insights from wide-angle seismic

    NASA Astrophysics Data System (ADS)

    Davy, Richard; Minshull, Tim; Bayrakci, Gaye; Bull, Jon; Klaeschen, Dirk; Papenberg, Cord; Reston, Timothy; Sawyer, Dale; Zelt, Colin

    2016-04-01

    Anomalously thin oceanic crust and expanses of exhumed and serpentinised mantle material at magma-poor rift margins are now a globally observed phenomena that characterizes the seaward limit of the continent-ocean transition. Hyperextension of continental crust at the Deep Galicia rifted margin in the North Atlantic has been accommodated by the rotation of continental fault blocks, which are underlain by the S-reflector, an interpreted detachment fault, along which exhumed and serpentinized mantle peridotite is observed. West of these features, the enigmatic Peridotite Ridge has been