Science.gov

Sample records for elekriki haste shekafande

  1. Hastings Center

    MedlinePlus

    ... on, and advocacy for, wiser health care and science policy. In addition to her leadership role at The Hastings Center, she is a professor at Harvard Medical School, where she directs the school’s Fellowship in Bioethics, a program that ...

  2. Disrupting the Education Monopoly: A Conversation with Reed Hastings

    ERIC Educational Resources Information Center

    Jacobs, Joanne

    2015-01-01

    This article features an interview with Netflix CEO, Reed Hastings. In this interview, Hastings relates that he told the "Wall Street Journal" in 2008 that he started looking at education--trying to figure out why our education is lagging when our technology is increasing at great rates and there's great innovation in so many other areas…

  3. VIEW OF PIEDMONT AVENUE AT INTERSECTION OF HASTE STREET, CHATEAU ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF PIEDMONT AVENUE AT INTERSECTION OF HASTE STREET, CHATEAU APARTMENTS BY CLARENCE CASEBOLT DAKIN, 1929 AT 2747 HASTE ON WEST SIDE OF PIEDMONT. LOOKING NORTH. Photograph by Fredrica Drotos and Michael Kelly, July 8, 2006 - Piedmont Way & the Berkeley Property Tract, East of College Avenue between Dwight Way & U.C. Memorial Stadium, Berkeley, Alameda County, CA

  4. E SERIES MAGAZINES FROM HASTINGS ST. SHOWING ACCESS DRIVE AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    E SERIES MAGAZINES FROM HASTINGS ST. SHOWING ACCESS DRIVE AND LOADING PLATFORMS. E 103 MAGAZINES IN FORGROUND. - Naval Magazine Lualualei, Headquarters Branch, Magazine Type, Eleventh, Thirteenth, Fifteenth, Sixteenth, & Seventeenth Streets, Pearl City, Honolulu County, HI

  5. The Lady Hastings' Charity Schools: Accounting for Eighteenth-Century Rural Philanthropy.

    ERIC Educational Resources Information Center

    Baker, Mae

    1997-01-01

    Describes the philanthropic activities of Lady Elizabeth Hastings and the local provision of rural charity schools in 18th-century England. Covers Hastings' background, her establishment of girls' charity schools, charity-school curricula, the Society for the Promotion of Christian Knowledge, and charity-school teachers. Evaluates Hastings'…

  6. The surgeon's assistant: an orthopaedic model at Hastings.

    PubMed

    Stenhouse, N; Gallannaugh, S C

    1996-07-01

    An Orthopaedic Surgeon's Assistant has been part of the orthopaedic surgical team at Hastings since 1983. Having a suitably trained person in post ensures continuity and stability and enhances the treatment of patients, the performance of the department and the training offered to Higher Surgical Trainees. Discussion includes the value of such a role, other orthopaedic models and the need for a nationally accredited training scheme and qualification.

  7. The Hastings Center and the early years of bioethics.

    PubMed

    Callahan, Daniel

    2012-02-01

    The Hastings Center was founded in 1969 to study ethical problems in medicine and biology. The Center arose from a confluence of three social currents: the increased public scrutiny of medicine and its practices, the concern about the moral problems being generated by technological developments, and the desire of one of its founders (Callahan) to make use of his philosophical training in a more applied way. The early years of the Center were devoted to raising money, developing an early agenda of issues, and identifying a cadre of people around the country interested in the issues. Various stresses and strains in the Center and the field are identified, and some final reflections are offered on the nature and value of the contributions made by bioethics as an academic field.

  8. A general construction for parallelizing Metropolis−Hastings algorithms

    PubMed Central

    Calderhead, Ben

    2014-01-01

    Markov chain Monte Carlo methods (MCMC) are essential tools for solving many modern-day statistical and computational problems; however, a major limitation is the inherently sequential nature of these algorithms. In this paper, we propose a natural generalization of the Metropolis−Hastings algorithm that allows for parallelizing a single chain using existing MCMC methods. We do so by proposing multiple points in parallel, then constructing and sampling from a finite-state Markov chain on the proposed points such that the overall procedure has the correct target density as its stationary distribution. Our approach is generally applicable and straightforward to implement. We demonstrate how this construction may be used to greatly increase the computational speed and statistical efficiency of a variety of existing MCMC methods, including Metropolis-Adjusted Langevin Algorithms and Adaptive MCMC. Furthermore, we show how it allows for a principled way of using every integration step within Hamiltonian Monte Carlo methods; our approach increases robustness to the choice of algorithmic parameters and results in increased accuracy of Monte Carlo estimates with little extra computational cost. PMID:25422442

  9. Metropolis-Hastings Robbins-Monro Algorithm for Confirmatory Item Factor Analysis

    ERIC Educational Resources Information Center

    Cai, Li

    2010-01-01

    Item factor analysis (IFA), already well established in educational measurement, is increasingly applied to psychological measurement in research settings. However, high-dimensional confirmatory IFA remains a numerical challenge. The current research extends the Metropolis-Hastings Robbins-Monro (MH-RM) algorithm, initially proposed for…

  10. High-Dimensional Exploratory Item Factor Analysis by a Metropolis-Hastings Robbins-Monro Algorithm

    ERIC Educational Resources Information Center

    Cai, Li

    2010-01-01

    A Metropolis-Hastings Robbins-Monro (MH-RM) algorithm for high-dimensional maximum marginal likelihood exploratory item factor analysis is proposed. The sequence of estimates from the MH-RM algorithm converges with probability one to the maximum likelihood solution. Details on the computer implementation of this algorithm are provided. The…

  11. Recreational Development and Fish and Wildlife Enhancement, Lake Rebecca, Hastings, Minnesota.

    DTIC Science & Technology

    1978-03-01

    birdlife, primarily because it is the main stem of the Mississippi flyway and within an area of overlapping eastern and western ornithological ranges...Historical Society has been consulted for cultural resources located in the Hastings vicinity. There are a number of prehistoric, historic, and...Park Commission Minnesota Pollution Control Agency Minnesota Historical Society Minnesota Water Resources Board Minnesota State Archaeologist

  12. Selected water-quality characteristics in the upper Mississippi River basin, Royalton to Hastings, Minnesota

    USGS Publications Warehouse

    Have, M.R.

    1991-01-01

    Results of this study show that the quality of water in the Mississippi River as it leaves the accounting unit at Hastings is not representative of water quality in most of the accounting unit. Three water-quality regions have been identified, and sampling sites are needed in each region to assess the quality of streams throughout the study area adequately.

  13. A Monte Carlo Metropolis-Hastings algorithm for sampling from distributions with intractable normalizing constants.

    PubMed

    Liang, Faming; Jin, Ick-Hoon

    2013-08-01

    Simulating from distributions with intractable normalizing constants has been a long-standing problem in machine learning. In this letter, we propose a new algorithm, the Monte Carlo Metropolis-Hastings (MCMH) algorithm, for tackling this problem. The MCMH algorithm is a Monte Carlo version of the Metropolis-Hastings algorithm. It replaces the unknown normalizing constant ratio by a Monte Carlo estimate in simulations, while still converges, as shown in the letter, to the desired target distribution under mild conditions. The MCMH algorithm is illustrated with spatial autologistic models and exponential random graph models. Unlike other auxiliary variable Markov chain Monte Carlo (MCMC) algorithms, such as the Møller and exchange algorithms, the MCMH algorithm avoids the requirement for perfect sampling, and thus can be applied to many statistical models for which perfect sampling is not available or very expensive. The MCMH algorithm can also be applied to Bayesian inference for random effect models and missing data problems that involve simulations from a distribution with intractable integrals.

  14. General Metropolis-Hastings jump diffusions for automatic target recognition in infrared scenes

    NASA Astrophysics Data System (ADS)

    Lanterman, Aaron D.; Miller, Michael I.; Snyder, Donald L.

    1997-04-01

    To locate and recognize ground-based targets in forward- looking IR (FLIR) images, 3D faceted models with associated pose parameters are formulated to accommodate the variability found in FLIR imagery. Taking a Bayesian approach, scenes are simulated from the emissive characteristics of the CAD models and compared with the collected data by a likelihood function based on sensor statistics. This likelihood is combined with a prior distribution defined over the set of possible scenes to form a posterior distribution. To accommodate scenes with variable numbers of targets, the posterior distribution is defined over parameter vectors of varying dimension. An inference algorithm based on Metropolis-Hastings jump- diffusion processes empirically samples from the posterior distribution, generating configurations of templates and transformations that match the collected sensor data with high probability. The jumps accommodate the addition and deletion of targets and the estimation of target identities; diffusions refine the hypotheses by drifting along the gradient of the posterior distribution with respect to the orientation and position parameters. Previous results on jumps strategies analogous to the Metropolis acceptance/rejection algorithm, with proposals drawn from the prior and accepted based on the likelihood, are extended to encompass general Metropolis-Hastings proposal densities. In particular, the algorithm proposes moves by drawing from the posterior distribution over computationally tractible subsets of the parameter space. The algorithm is illustrated by an implementation on a Silicon Graphics Onyx/Reality Engine.

  15. 76 FR 58241 - Designation for the Aberdeen, SD; Decatur, IL; Hastings, NE; Fulton, IL; the State of Missouri...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-20

    ... services under the United States Grain Standards Act, as amended (USGSA). DATES: Effective Date: October 1... From the Federal Register Online via the Government Publishing Office ] DEPARTMENT OF AGRICULTURE...; Hastings, NE; Fulton, IL; the State of Missouri, and the State of South Carolina Areas AGENCY:...

  16. Efficient implementation of the Metropolis-Hastings algorithm, with application to the Cormack-Jolly-Seber model

    USGS Publications Warehouse

    Link, W.A.; Barker, R.J.

    2008-01-01

    Judicious choice of candidate generating distributions improves efficiency of the Metropolis-Hastings algorithm. In Bayesian applications, it is sometimes possible to identify an approximation to the target posterior distribution; this approximate posterior distribution is a good choice for candidate generation. These observations are applied to analysis of the Cormack-Jolly-Seber model and its extensions. ?? Springer Science+Business Media, LLC 2007.

  17. A Sanctuary for Science: The Hastings Natural History Reservation and the Origins of the University of California's Natural Reserve System.

    PubMed

    Alagona, Peter S

    2012-01-01

    In 1937 Joseph Grinnell founded the University of California's (U.C.) first biological field station, the Hastings Natural History Reservation. Hastings became a center for field biology on the West Coast, and by 1960 it was serving as a model for the creation of additional U.C. reserves. Today, the U.C. Natural Reserve System (NRS) is the largest and most diverse network of university-based biological field stations in the world, with 36 sites covering more than 135,000 acres. This essay examines the founding of the Hastings Reservation, and asks how it managed to grow and develop, in the 1940s and 1950s, during a time of declining support for natural history research. It shows how faculty and staff courted the support of key institutional allies, presented themselves as the guardians of a venerable tradition in nature study, and emphasized the station's capacity to document ecological change and inform environmental policy and management. In the years since, Hastings and other U.C. reserves have played crucial roles in California environmental politics. Biological field stations in the post-war era deserve more attention not only from historians of biology, but also from environmental historians and other scholars interested in the role of science in society.

  18. Estimation of Contextual Effects through Nonlinear Multilevel Latent Variable Modeling with a Metropolis-Hastings Robbins-Monro Algorithm

    ERIC Educational Resources Information Center

    Yang, Ji Seung; Cai, Li

    2014-01-01

    The main purpose of this study is to improve estimation efficiency in obtaining maximum marginal likelihood estimates of contextual effects in the framework of nonlinear multilevel latent variable model by adopting the Metropolis-Hastings Robbins-Monro algorithm (MH-RM). Results indicate that the MH-RM algorithm can produce estimates and standard…

  19. Metropolis–Hastings thermal state sampling for numerical simulations of Bose–Einstein condensates

    PubMed Central

    Grišins, Pjotrs; Mazets, Igor E.

    2014-01-01

    We demonstrate the application of the Metropolis–Hastings algorithm to sampling of classical thermal states of one-dimensional Bose–Einstein quasicondensates in the classical fields approximation, both in untrapped and harmonically trapped case. The presented algorithm can be easily generalized to higher dimensions and arbitrary trap geometry. For truncated Wigner simulations the quantum noise can be added with conventional methods (half a quantum of energy in every mode). The advantage of the presented method over the usual analytical and stochastic ones lies in its ability to sample not only from canonical and grand canonical distributions, but also from the generalized Gibbs ensemble, which can help to shed new light on thermodynamics of integrable systems. PMID:25843966

  20. Dynamical behavior of fractional-order Hastings-Powell food chain model and its discretization

    NASA Astrophysics Data System (ADS)

    Matouk, A. E.; Elsadany, A. A.; Ahmed, E.; Agiza, H. N.

    2015-10-01

    In this work, the dynamical behavior of fractional-order Hastings-Powell food chain model is investigated and a new discretization method of the fractional-order system is introduced. A sufficient condition for existence and uniqueness of the solution of the proposed system is obtained. Local stability of the equilibrium points of the fractional-order system is studied. Furthermore, the necessary and sufficient conditions of stability of the discretized system are also studied. It is shown that the system's fractional parameter has effect on the stability of the discretized system which shows rich variety of dynamical behaviors such as Hopf bifurcation, an attractor crisis and chaotic attractors. Numerical simulations show the tea-cup chaotic attractor of the fractional-order system and the richer dynamical behavior of the corresponding discretized system.

  1. Time Lapse Gravity and Seismic Monitoring of CO2 Injection at the West Hastings Field, Texas

    NASA Astrophysics Data System (ADS)

    Ferguson, J. F.; Richards, T.; Klopping, F.; MacQueen, J.; Hosseini, S. A.

    2015-12-01

    Time lapse or 4D gravity and seismic reflection surveys are being conducted at the West Hastings Field near Houston, Texas to monitor the progress of CO2 injection. This Department of Energy supported CO2 sequestration experiment is conducted in conjunction with a Denbury Onshore, LLC tertiary recovery project. The reservoir is at a depth of 1.8 km in the Oligocene Frio sands and has been produced since the 1930s. Goals are an accounting and mapping of the injected CO2 and to determine if migration occurs along intra-reservoir faults. An integrated interpretation of the geophysical surveys will be made together with well logs and engineering data. Gravity monitoring of water versus gas replacement has been very successful, but liquid phase CO2 monitoring is problematic due to the smaller density contrast with respect to oil and water. This reservoir has a small volume to depth ratio and hence only a small gravity difference signal is expected on the surface. New borehole gravity technology introduced by Micro-g-Lacoste can make gravity measurements at near reservoir depths with a much higher signal to noise ratio. This method has been successfully evaluated on a simulation of the Hastings project. Field operations have been conducted for repeated surface and borehole gravity surveys beginning in 2013. The surface survey of 95 stations covers an area of 3 by 5 km and 22 borehole gravity logs are run in the interval above the Frio formation. 4D seismic reflection surveys are being made at 6 month intervals on the surface and in 3 VSP wells. CO2 injection into the targeted portion of the reservoir only began in early 2015 and monitoring will continue into 2017. To date only the baseline reservoir conditions have been assessed. The overall success of the gravity monitoring will not be determined until 2017.

  2. Chaos control of Hastings-Powell model by combining chaotic motions

    NASA Astrophysics Data System (ADS)

    Danca, Marius-F.; Chattopadhyay, Joydev

    2016-04-01

    In this paper, we propose a Parameter Switching (PS) algorithm as a new chaos control method for the Hastings-Powell (HP) system. The PS algorithm is a convergent scheme that switches the control parameter within a set of values while the controlled system is numerically integrated. The attractor obtained with the PS algorithm matches the attractor obtained by integrating the system with the parameter replaced by the averaged value of the switched parameter values. The switching rule can be applied periodically or randomly over a set of given values. In this way, every stable cycle of the HP system can be approximated if its underlying parameter value equalizes the average value of the switching values. Moreover, the PS algorithm can be viewed as a generalization of Parrondo's game, which is applied for the first time to the HP system, by showing that losing strategy can win: "losing + losing = winning." If "loosing" is replaced with "chaos" and, "winning" with "order" (as the opposite to "chaos"), then by switching the parameter value in the HP system within two values, which generate chaotic motions, the PS algorithm can approximate a stable cycle so that symbolically one can write "chaos + chaos = regular." Also, by considering a different parameter control, new complex dynamics of the HP model are revealed.

  3. Chaos control of Hastings-Powell model by combining chaotic motions.

    PubMed

    Danca, Marius-F; Chattopadhyay, Joydev

    2016-04-01

    In this paper, we propose a Parameter Switching (PS) algorithm as a new chaos control method for the Hastings-Powell (HP) system. The PS algorithm is a convergent scheme that switches the control parameter within a set of values while the controlled system is numerically integrated. The attractor obtained with the PS algorithm matches the attractor obtained by integrating the system with the parameter replaced by the averaged value of the switched parameter values. The switching rule can be applied periodically or randomly over a set of given values. In this way, every stable cycle of the HP system can be approximated if its underlying parameter value equalizes the average value of the switching values. Moreover, the PS algorithm can be viewed as a generalization of Parrondo's game, which is applied for the first time to the HP system, by showing that losing strategy can win: "losing + losing = winning." If "loosing" is replaced with "chaos" and, "winning" with "order" (as the opposite to "chaos"), then by switching the parameter value in the HP system within two values, which generate chaotic motions, the PS algorithm can approximate a stable cycle so that symbolically one can write "chaos + chaos = regular." Also, by considering a different parameter control, new complex dynamics of the HP model are revealed.

  4. Estimation of Contextual Effects through Nonlinear Multilevel Latent Variable Modeling with a Metropolis-Hastings Robbins-Monro Algorithm. CRESST Report 833

    ERIC Educational Resources Information Center

    Yang, Ji Seung; Cai, Li

    2013-01-01

    The main purpose of this study is to improve estimation efficiency in obtaining full-information maximum likelihood (FIML) estimates of contextual effects in the framework of a nonlinear multilevel latent variable model by adopting the Metropolis-Hastings Robbins-Monro algorithm (MH-RM; Cai, 2008, 2010a, 2010b). Results indicate that the MH-RM…

  5. On the Metropolis-Hastings acceptance probability to add or drop a quantitative trait locus in Markov chain Monte Carlo-based Bayesian analyses.

    PubMed Central

    Jannink, Jean-Luc; Fernando, Rohan L

    2004-01-01

    The Metropolis-Hastings algorithm used in analyses that estimate the number of QTL segregating in a mapping population requires the calculation of an acceptance probability to add or drop a QTL from the model. Expressions for this acceptance probability need to recognize that sets of QTL are unordered such that the number of equivalent sets increases with the factorial of the QTL number. Here, we show how accounting for this fact affects the acceptance probability and review expressions found in the literature. PMID:15020452

  6. Two-dimensional direct-current resistivity survey to supplement borehole data in ground-water models of the former Blaine Naval Ammunition Depot, Hastings, Nebraska, September 2003

    USGS Publications Warehouse

    Kress, Wade H.; Ball, Lyndsay B.; Teeple, Andrew; Turco, Michael J.

    2006-01-01

    The former Blaine Naval Ammunition Depot located immediately southeast of Hastings, Nebraska, was an ammunition facility during World War II and the Korean Conflict. Waste-management practices during operation and decommissioning of the former Depot resulted in soil and ground-water contamination. Ground-water models have been used by the U.S. Army Corps of Engineers to provide information on the fate and transport of contaminants on the former Depot site. During September 2003, the U.S. Geological Survey, in cooperation with the U.S. Army Corps of Engineers, Kansas City District, conducted a pilot study to collect two-dimensional direct-current resistivity data on the site along six profiles near existing monitoring wells. The inversion results of field data from five of the six two-dimensional direct-current resistivity profiles display distinct electrical stratigraphy consistent with three resistivity units (low resistivity, high resistivity, and low resistivity). These three resistivity units correlate with rock-stratigraphic or hydrogeologic units described prior to this study. To interpret the resistivity profiles, additional data extending through the lower confining unit into the underlying Niobrara Formation could be used with the existing data to construct forward models for data analysis and interpretation.

  7. Benefits of a new Metropolis-Hasting based algorithm, in non-linear regression for estimation of ex vivo antimalarial sensitivity in patients infected with two strains.

    PubMed

    Bauer, Rebecca; Mentré, France; Kaddouri, Halima; Le Bras, Jacques; Le Nagard, Hervé

    2014-12-01

    Malaria is one of the world׳s most widespread parasitic diseases. The parasitic protozoans of the genus Plasmodium have developed resistance to several antimalarial drugs. Some patients are therefore infected by two or more strains with different levels of antimalarial drug sensitivity. We previously developed a model to estimate the drug concentration (IC50) that inhibits 50% of the growth of the parasite isolated from a patient infected with one strain. We propose here a new Two-Slopes model for patients infected by two strains. This model involves four parameters: the proportion of each strain and their IC50, and the sigmoidicity parameter. To estimate the parameters of this model, we have developed a new algorithm called PGBO (Population Genetics-Based Optimizer). It is based on the Metropolis-Hasting algorithm and is implemented in the statistical software R. We performed a simulation study and defined three evaluation criteria to evaluate its properties and compare it with three other algorithms (Gauss-Newton, Levenberg-Marquardt, and a simulated annealing). We also evaluated it using in vitro data and three ex vivo datasets from the French Malaria Reference Center. Our evaluation criteria in the simulation show that PGBO gives good estimates of the parameters even if the concentration design is poor. Moreover, our algorithm is less sensitive than Gauss-Newton algorithms to initial values. Although parameter estimation is good, interpretation of the results can be difficult if the proportion of the second strain is close to 0 or 1. For these reasons, this approach cannot yet be implemented routinely.

  8. Using satellite observations to improve model estimates of CO2 and CH4 flux: a Metropolis Hastings Markov Chain Monte Carlo approach

    NASA Astrophysics Data System (ADS)

    MacBean, Natasha; Disney, Mathias; Lewis, Philip; Ineson, Phil

    2010-05-01

    profile as a whole. We present results from an Observing System Simulation Experiment (OSSE) designed to investigate the impact of management and climate change on peatland carbon fluxes, as well as how observations from satellites may be able to constrain modeled carbon fluxes. We use an adapted version of the Carnegie-Ames-Stanford Approach (CASA) model (Potter et al., 1993) that includes a representation of methane dynamics (Potter, 1997). The model formulation is further modified to allow for assimilation of satellite observations of surface soil moisture and land surface temperature. The observations are used to update model estimates using a Metropolis Hastings Markov Chain Monte Carlo (MCMC) approach. We examine the effect of temporal frequency and precision of satellite observations with a view to establishing how, and at what level, such observations would make a significant improvement in model uncertainty. We compare this with the system characteristics of existing and future satellites. We believe this is the first attempt to assimilate surface soil moisture and land surface temperature into an ecosystem model that includes a full representation of CH4 flux. Bubier, J., and T. Moore (1994), An ecological perspective on methane emissions from northern wetlands, TREE, 9, 460-464. Charman, D. (2002), Peatlands and Environmental Change, JohnWiley and Sons, Ltd, England. Gorham, E. (1991), Northern peatlands: Role in the carbon cycle and probable responses to climatic warming, Ecological Applications, 1, 182-195. Lai, D. (2009), Methane dynamics in northern peatlands: A review, Pedosphere, 19, 409-421. Le Mer, J., and P. Roger (2001), Production, oxidation, emission and consumption of methane by soils: A review, European Journal of Soil Biology, 37, 25-50. Limpens, J., F. Berendse, J. Canadell, C. Freeman, J. Holden, N. Roulet, H. Rydin, and Potter, C. (1997), An ecosystem simulation model for methane production and emission from wetlands, Global Biogeochemical

  9. Avoid haste in defining human muscular Sarcocystosis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We appreciate Dr. Italiano’s [1] interest in our article [2] and agree that our case definition, described in our methods as ‘intentionally specific,’ may have resulted in the exclusion of some travelers infected with Sarcocystis nesbitti. Nevertheless, we believe published data from outbreak invest...

  10. High Altitude Supersonic Target (HAST), Phase 2

    DTIC Science & Technology

    1974-08-01

    obtained using Flight Mission No. 1. The results of this analysis indicate necessary protection is provided by 3/16 inch of Fiberfrax ® insulation in...are protected by wraps of five layers of Fiberfrax ® (ceramic paper) in addition to the insulating tape; a technique tested to withstand greater than

  11. Cases in Bioethics from the Hastings Center Report.

    ERIC Educational Resources Information Center

    Levine, Carol, Ed.; Veatch, Robert M.

    Case studies of ethical issues based on real events are followed by comments illustrating how people from various ethical traditions and frameworks and from different academic and professional disciplines analyze the issues and work toward a resolution of the conflict posed. The cases are intended to help the public and professional persons pursue…

  12. Preliminary Flight Rating Tests of the HAST Propulsion System

    DTIC Science & Technology

    1975-01-01

    project engineer for propulsion was Mr. Fred Hewitt. Contractor personnel providing support included Messrs. William Bryne , James Auiler, Gary...Management Assembly ....... 11 Controlled Thrust Assembly .......... . Z Event Sequencing ................. 24 III TES.2 FACILITY...system will reliably perform the intended flight test missions, ( Z ) verify safe altitude ignition and operation so as to be able to certify flight safety

  13. VizieR Online Data Catalog: HST and Magellan observations of Haumea system (Hastings+, 2016)

    NASA Astrophysics Data System (ADS)

    Hastings, D. M.; Ragozzine, D.; Fabrycky, D. C.; Burkhart, L. D.; Fuentes, C.; Margot, J.-L.; Brown, M. E.; Holman, M.

    2017-01-01

    The Hubble Space Telescope (HST) observations of the Haumea system comprised five HST orbits' worth of 100s exposures of the Wide Field Planetary Camera 2 from 2009 February 4 (Program 11971) and 10 HST orbits' worth of 44s exposures of the Wide Field Camera 3 from 2010 June 28 (Program 12243). This system was also observed on the night of UT 2009 June 2 with the Magellan Baade telescope at Las Campanas Observatory in Chile. We used the Raymond and Beverly Sackler Magellan Instant Camera (MagIC). Observations were taken from the beginning of the night until it was unobservable, for a total of ~5hr. We centered the system on one of the four quadrants defined by the instrument's four amplifiers. The seeing was constant during the observations and consistently close to 0.5'', smaller than Hi'iaka's separation of 1.4''. The SITe CCD detector has a pixel scale of 0.069''/pixel. We set the exposure times at 120s to avoid saturation and optimize readout time. The filter selected was Johnson-Cousins R. Standard calibrations were taken at the beginning and end of the night. The telescope guiding system ensured that the pointing was constant to within an FWHM over the course of the observations. Table1 presents the relative normalized photometry inferred from our observations. (1 data file).

  14. When Does Haste Make Waste? Speed-Accuracy Tradeoff, Skill Level, and the Tools of the Trade

    ERIC Educational Resources Information Center

    Beilock, Sian L.; Bertenthal, Bennett I.; Hoerger, Michael; Carr, Thomas H.

    2008-01-01

    Novice and skilled golfers took a series of golf putts with a standard putter (Exp. 1) or a distorted "funny putter" (consisting of an s-shaped and arbitrarily weighted putter shaft; Exp. 2) under instructions to either (a) take as much time as needed to be accurate or to (b) putt as fast as possible while still being accurate. Planning and…

  15. Estimation of a Ramsay-Curve Item Response Theory Model by the Metropolis-Hastings Robbins-Monro Algorithm

    ERIC Educational Resources Information Center

    Monroe, Scott; Cai, Li

    2014-01-01

    In Ramsay curve item response theory (RC-IRT) modeling, the shape of the latent trait distribution is estimated simultaneously with the item parameters. In its original implementation, RC-IRT is estimated via Bock and Aitkin's EM algorithm, which yields maximum marginal likelihood estimates. This method, however, does not produce the…

  16. 77 FR 35960 - City of Hastings, MN; Notice of Application for Amendment of License and Soliciting Comments...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-15

    ... structure and anchored for stability using anchors and spuds; two synchronous alternating current (AC) generating units that sit atop the barge; a 225-ampere molded case circuit breaker along with a...

  17. Estimation of Contextual Effects through Nonlinear Multilevel Latent Variable Modeling with a Metropolis-Hastings Robbins-Monro Algorithm

    ERIC Educational Resources Information Center

    Yang, Ji Seung

    2012-01-01

    Nonlinear multilevel latent variable modeling has been suggested as an alternative to traditional hierarchical linear modeling to more properly handle measurement error and sampling error issues in contextual effects modeling. However, a nonlinear multilevel latent variable model requires significant computational effort because the estimation…

  18. Estimation of a Ramsay-Curve Item Response Theory Model by the Metropolis-Hastings Robbins-Monro Algorithm. CRESST Report 834

    ERIC Educational Resources Information Center

    Monroe, Scott; Cai, Li

    2013-01-01

    In Ramsay curve item response theory (RC-IRT, Woods & Thissen, 2006) modeling, the shape of the latent trait distribution is estimated simultaneously with the item parameters. In its original implementation, RC-IRT is estimated via Bock and Aitkin's (1981) EM algorithm, which yields maximum marginal likelihood estimates. This method, however,…

  19. Mississippi River 9-Foot Channel Navigation Pools, St. Anthony Falls Pools and Pools 1-10, Master Recreation Plan; Plan for Development, Lake Rebecca - Pool 2, Hastings, Minnesota. Supplement Number 1.

    DTIC Science & Technology

    1978-03-01

    of June and September when they are from the southeast. The seasonal change and variation in climate...end of Lake Rebecca, oil deposits remain in the sediments from an oil spill in 1970. This oil-saturated soil will be avoided for use as fill material...and development will not be planned in the area. 2.09 Though there are some restrictions on development because of soils , a large portion, of the soils

  20. Diversity of human astrovirus genotypes circulating in children with acute gastroenteritis in Thailand during 2000-2011.

    PubMed

    Malasao, Rungnapa; Khamrin, Pattara; Chaimongkol, Natthawan; Ushijima, Hiroshi; Maneekarn, Niwat

    2012-11-01

    Human astrovirus (HAstV) is one of the causative agents of acute gastroenteritis in children worldwide. The objective of this study was to elucidate the molecular epidemiology and genotypic diversity of HAstV circulating in pediatric patients admitted to hospital with diarrhea in Thailand during the year 2000-2011, except for 2004, 2006, and 2009. A total of 1,022 fecal specimens were tested for HAstV by reverse transcription polymerase chain reaction (RT-PCR). HAstV was detected at 1.4% (14 of 1,022). All HAstV strains detected in this study were characterized further by nucleotide sequencing and phylogenetic analysis. Analysis of 348 bp partial capsid nucleotide sequences revealed that HAstV strains detected were HAstV-1 (1a, 1b, and 1d) (8 strains), HAstV-2 (2c) (3 strains), HAstV-3 (1 strain), and HAstV-5 (2 strains). HAstV-1, the most predominant genotype was detected initially in 2002 and circulated continuously up to 2011. HAstV-2 was detected in year 2001, and 2007 and grouped into a 2c lineage. HAstV-3 was found only in 2000 and HAstV-5 was found in the year 2001. The findings indicate that a wide variety of HAstV strains continue to circulate in children admitted to hospital with acute gastroenteritis in Thailand over a decade. The data provide an epidemiological overview of HAstV infection and HAstV genotype distribution in Thailand.

  1. Results of Field and Laboratory Investigations Conducted for Remediation of Interim Response Actions, Other Contamination Sources. Volume 2. Appendixes

    DTIC Science & Technology

    1990-12-01

    of the alluvial groundwater. A.6.2 Previous Investigations Previous studies done in the Motor Pool Area include: a May 1984 RCRA audit done by the...19 HASTE STi. PFE 4/24/39 N I 6064 4/5/89 HASTE STIG. PE 4/24/189 N 6065 4/5/89 HASTE STAG. PPE 5/23/19 N 6069 4/14/89 HASTE STR. ??E 4/24/89 H 6070 4...13009 4117/69 HASTE STR6. PPE 5/1/89 K S13010 4/17/69 HVAST[ STAG. PIE 5/1/89 H 13011 4/17/10 HASTE STRG. PFE 0/4/89 Y 5/8 INCH HOSE 13012 4/17/19 HASTE

  2. Complete genome sequence of human astrovirus genotype 6

    PubMed Central

    2010-01-01

    Background Human astroviruses (HAstVs) are one of the important causes of acute gastroenteritis in children. Currently, eight HAstV genotypes have been identified and all but two (HAstV-6 and HAstV-7) have been fully sequenced. We here sequenced and analyzed the complete genome of a HAstV-6 strain (192-BJ07), which was identified in Beijing, China. Results The genome of 192-BJ07 consists of 6745 nucleotides. The 192-BJ07 strain displays a 77.2-78.0% nucleotide sequence identity with other HAstV genotypes and exhibits amino acid sequence identities of 86.5-87.4%, 94.2-95.1%, and 65.5-74.8% in the ORF1a, ORF1b, and ORF2 regions, respectively. Homological analysis of ORF2 shows that 192-BJ07 is 96.3% identical to the documented HAstV-6 strain. Further, phylogenetic analysis indicates that different genomic regions are likely undergoing different evolutionary and selective pressures. No recombination event was observed in HAstV-6 in this study. Conclusion The completely sequenced and characterized genome of HAstV-6 (192-BJ07) provides further insight into the genetics of astroviruses and aids in the surveillance and control of HAstV gastroenteritis. PMID:20137100

  3. Structure of a Human Astrovirus Capsid-Antibody Complex and Mechanistic Insights into Virus Neutralization

    SciTech Connect

    Bogdanoff, Walter A.; Campos, Jocelyn; Perez, Edmundo I.; Yin, Lu; Alexander, David L.; DuBois, Rebecca M.; López, Susana

    2016-11-02

    ABSTRACT

    Human astroviruses (HAstVs) are a leading cause of viral diarrhea in young children, the immunocompromised, and the elderly. There are no vaccines or antiviral therapies against HAstV disease. Several lines of evidence point to the presence of protective antibodies in healthy adults as a mechanism governing protection against reinfection by HAstV. However, development of anti-HAstV therapies is hampered by the gap in knowledge of protective antibody epitopes on the HAstV capsid surface. Here, we report the structure of the HAstV capsid spike domain bound to the neutralizing monoclonal antibody PL-2. The antibody uses all six complementarity-determining regions to bind to a quaternary epitope on each side of the dimeric capsid spike. We provide evidence that the HAstV capsid spike is a receptor-binding domain and that the antibody neutralizes HAstV by blocking virus attachment to cells. We identify patches of conserved amino acids that overlap the antibody epitope and may comprise a receptor-binding site. Our studies provide a foundation for the development of therapies to prevent and treat HAstV diarrheal disease.

    IMPORTANCEHuman astroviruses (HAstVs) infect nearly every person in the world during childhood and cause diarrhea, vomiting, and fever. Despite the prevalence of this virus, little is known about how antibodies in healthy adults protect them against reinfection. Here, we determined the crystal structure of a complex of the HAstV capsid protein and a virus-neutralizing antibody. We show that the antibody binds to the outermost spike domain of the capsid, and we provide evidence that the antibody blocks virus attachment to human cells. Importantly, our findings suggest that a subunit-based vaccine focusing the immune system on the HAstV capsid spike domain could be effective in protecting children against HAstV disease.

  4. 75 FR 76778 - Environmental Impact Statement for the Milwaukee, WI (Milwaukee Intermodal Station) to...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-09

    ... Canadian Pacific Railway (CP) right-of-way from Milwaukee, WI to Watertown, WI; right-of-way owned by the... Madison, WI; CP right-of-way from Johnson Street Yard in Madison through Portage, WI and La Crosse, WI to Red Wing, MN and to Hastings, MN; CP or BNSF Railway Co. (BNSF) right-of-way from Hastings, MN to...

  5. Wisdom from the Factory Floor: For Best Results, Limit Initiatives, Build Capacity, and Monitor Progress

    ERIC Educational Resources Information Center

    Dumas, Chad; Kautz, Craig

    2014-01-01

    In the Hastings Nebraska Public schools, two of the eight schools have been identified as national models of educational effectiveness. In seven of eight buildings, in just four years, student test scores have increased from around 60% proficiency to around 80% proficiency or better. At Hastings, central office leaders emphasize three key…

  6. 1. Photocopied October 1976, from F.B. Tower, Illistrations of the ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. Photocopied October 1976, from F.B. Tower, Illistrations of the Croton Aqueduct, New York: Wiley and Putnam, 1843. CROTON AQUEDUCT AT HASTINGS: ARCH PROVIDED ACCESS TO STONE QUARRY. PLATE XVII, PAGE 106. - Old Croton Aqueduct, Quarry Railroad Bridge, Aqueduct Lane at Williams Street, Hastings-on-Hudson, Westchester County, NY

  7. Surveillance of Human Astrovirus Infection in Brazil: The First Report of MLB1 Astrovirus

    PubMed Central

    Xavier, Maria da Penha Trindade Pinheiro; Carvalho Costa, Filipe Aníbal; Rocha, Mônica Simões; de Andrade, Juliana da Silva Ribeiro; Diniz, Fernanda Kreischer Bandeira; de Andrade, Thais Ramos; Miagostovich, Marize Pereira; Leite, José Paulo Gagliardi; Volotão, Eduardo de Mello

    2015-01-01

    Human astrovirus (HAstV) represents the third most common virus associated with acute diarrhea (AD). This study aimed to estimate the prevalence of HAstV infection in Brazilian children under 5 years of age with AD, investigate the presence of recently described HAstV strains, through extensive laboratory-based surveillance of enteric viral agents in three Brazilian coastal regions between 2005 and 2011. Using reverse transcription-polymerase chain reaction (RT-PCR), the overall HAstV detection rate reached 7.1% (207/2.913) with percentage varying according to the geographic region: 3.9% (36/921) in the northeast, 7.9% in the south (71/903) and 9.2% in the southeast (100/1.089) (p < 0.001). HAstV were detected in cases of all age groups. Detection rates were slightly higher during the spring. Nucleotide sequence analysis of a 320-bp ORF2 fragment revealed that HAstV-1 was the predominant genotype throughout the seven years of the study. The novel AstV-MLB1 was detected in two children with AD from a subset of 200 samples tested, demonstrating the circulation of this virus both the in northeastern and southeastern regions of Brazil. These results provide additional epidemiological and molecular data on HAstV circulation in three Brazilian coastal regions, highlighting its potential to cause infantile AD. PMID:26274322

  8. 24. BUILDING NO. 266, GENERAL PURPOSE LABORATORY (ORIGINALLY MAGAZINE FOR ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    24. BUILDING NO. 266, GENERAL PURPOSE LABORATORY (ORIGINALLY MAGAZINE FOR HE 'A' PUMP & CHANGE HOUSE), LOOKING HAST AT NORTHWEST SIDE OF BUILDING. - Picatinny Arsenal, 200 Area, Shell Component Loading, State Route 15 near I-80, Dover, Morris County, NJ

  9. Geoscientists for international development

    USGS Publications Warehouse

    Hastings, David A.

    1980-01-01

    Professional societies are usually concerned with the advancement of scientific knowledge, but a relative newcomer to the international scene has a different focus - geoscience development in the Third World. David Hastings, a member of AGID, explains.

  10. Plastic encapsulated parts

    SciTech Connect

    Castillo, T.

    1994-10-01

    Plastic semiconductor packages were characterized as possible alternatives for canned devices, which are susceptible to internal shorts caused by conductive particles. Highly accelerated stress testing (HAST) as well as electrical and mechanical testing were conducted on plastic technology devices.

  11. 3. Historic American Buildings Survey California State Library Collection Sacramento ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. Historic American Buildings Survey California State Library Collection Sacramento Co. History Thompson & West Sketch of 1880 Rephoto 1960 NORTHEAST CORNER - B. F. Hastings Bank Building, 128-132 J Street, Sacramento, Sacramento County, CA

  12. 75 FR 10347 - Federal Property Suitable as Facilities To Assist the Homeless

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-05

    ...--hunting, subject to existing easements. Nevada Approx. 22 acres Mount Diablo Henderson NV Landholding... recent use--Ohio Air Natl Guard site. PFC Joe R. Hastings Army Reserve Center 3120 Parkway Dr. Canton...

  13. PTB Binds to the 3’ Untranslated Region of the Human Astrovirus Type 8: A Possible Role in Viral Replication

    PubMed Central

    Espinosa-Hernández, Wendy; Velez-Uriza, Dora; Valdés, Jesús; Vélez-Del Valle, Cristina; Salas-Benito, Juan; Martínez-Contreras, Rebeca; García-Espítia, Matilde; Salas-Benito, Mariana; Vega-Almeida, Tania; De Nova-Ocampo, Mónica

    2014-01-01

    The 3′ untranslated region (3′UTR) of human astroviruses (HAstV) consists of two hairpin structures (helix I and II) joined by a linker harboring a conserved PTB/hnRNP1 binding site. The identification and characterization of cellular proteins that interact with the 3′UTR of HAstV-8 virus will help to uncover cellular requirements for viral functions. To this end, mobility shift assays and UV cross-linking were performed with uninfected and HAstV-8-infected cell extracts and HAstV-8 3′UTR probes. Two RNA-protein complexes (CI and CII) were recruited into the 3′UTR. Complex CII formation was compromised with cold homologous RNA, and seven proteins of 35, 40, 45, 50, 52, 57/60 and 75 kDa were cross-linked to the 3′UTR. Supermobility shift assays indicated that PTB/hnRNP1 is part of this complex, and 3′UTR-crosslinked PTB/hnRNP1 was immunoprecipitated from HAstV-8 infected cell-membrane extracts. Also, immunofluorescence analyses revealed that PTB/hnRNP1 is distributed in the nucleus and cytoplasm of uninfected cells, but it is mainly localized perinuclearly in the cytoplasm of HAstV-8 infected cells. Furthermore, the minimal 3′UTR sequences recognized by recombinant PTB are those conforming helix I, and an intact PTB/hnRNP1-binding site. Finally, small interfering RNA-mediated PTB/hnRNP1 silencing reduced synthesis viral genome and virus yield in CaCo2 cells, suggesting that PTB/hnRNP1 is required for HAstV replication. In conclusion, PTB/hnRNP1 binds to the 3′UTR HAstV-8 and is required or participates in viral replication. PMID:25406089

  14. Human Astroviruses

    PubMed Central

    Pintó, Rosa M.; Guix, Susana

    2014-01-01

    SUMMARY Human astroviruses (HAtVs) are positive-sense single-stranded RNA viruses that were discovered in 1975. Astroviruses infecting other species, particularly mammalian and avian, were identified and classified into the genera Mamastrovirus and Avastrovirus. Through next-generation sequencing, many new astroviruses infecting different species, including humans, have been described, and the Astroviridae family shows a high diversity and zoonotic potential. Three divergent groups of HAstVs are recognized: the classic (MAstV 1), HAstV-MLB (MAstV 6), and HAstV-VA/HMO (MAstV 8 and MAstV 9) groups. Classic HAstVs contain 8 serotypes and account for 2 to 9% of all acute nonbacterial gastroenteritis in children worldwide. Infections are usually self-limiting but can also spread systemically and cause severe infections in immunocompromised patients. The other groups have also been identified in children with gastroenteritis, but extraintestinal pathologies have been suggested for them as well. Classic HAstVs may be grown in cells, allowing the study of their cell cycle, which is similar to that of caliciviruses. The continuous emergence of new astroviruses with a potential zoonotic transmission highlights the need to gain insights on their biology in order to prevent future health threats. This review focuses on the basic virology, pathogenesis, host response, epidemiology, diagnostic assays, and prevention strategies for HAstVs. PMID:25278582

  15. Epidemiological Characteristics of Sapovirus and Human Astrovirus Detected among Children in Nara Prefecture, Japan, during the 2009/2010-2014/2015 Seasons.

    PubMed

    Yoneda, Masaki; Nakano, Mamoru; Sugimoto, Daichi; Inada, Machi; Fujitani, Misako; Kitahori, Yoshiteru

    2017-01-24

    The current study elucidated the epidemiological characteristics of sapovirus (SaV) and human astrovirus (HAstV) associated with gastroenteritis among children in regional populations of Nara Prefecture, Japan, during the 2009/2010-2014/2015 seasons. The SaV detection rate was 7.5% (71/948) according to reverse transcription-polymerase chain reaction. A high SaV detection rate of 13.5% was observed among children 4 years of age. The highest SaV detection rate was observed in June (19.2%), followed by July (11.1%). The detected SaV included 7 genotypes: GI.1, GI.2, GII.3, GII.1, GI.3, GII.2, and GV, in order of decreasing prevalence. In comparison, the HAstV detection rate was 4.2% (40/948). The HAstV detection rate among children 4 years of age was 12.2%. The HAstV detection rate was highest in July (13.9%), followed by May (10.5%) and August (6.7%). The detected HAstVs included genotypes 1, 4, 6, and 8. The most prevalent genotype was 1, followed by 4 and 8. This report provides an epidemiological overview of SaV and HAstV infection in Nara Prefecture, Japan.

  16. Complete genome sequencing of a recombinant strain between human astrovirus antigen types 2 and 8 isolated from South Korea.

    PubMed

    Ha, Hyun-Ju; Lee, Sung-Geun; Cho, Han-Gil; Jin, Ji-Young; Lee, Jae Woong; Paik, Soon-Yong

    2016-04-01

    Human astroviruses (HAstVs) occur worldwide and are known to the causative agents of diarrhea in infants and elderly patients with immune dysfunction. This study aimed to identify recombinant HAstV strains and characterize rare genotypes. The full-length genome of a recombinant HAstV strain isolated from the stool sample of a patient with acute gastroenteritis from South Korea was amplified using three pairs of previously designed primers and seven newly designed primers. The recombinant HAstV was 6757-bp long and contained three sequential open reading frames (ORFs), designated as ORF1a (2781 bp), ORF1b (1548 bp), and ORF2 (2349 bp). Our findings suggested that a recombination event had occurred between ORF1b and ORF2 of the isolated strain, with a recombination breakpoint at 4081 bp. To our knowledge, this is the first study to reveal the complete nucleotide sequence of a recombinant HAstV strain from South Korea. Our study findings might be useful for identifying other recombinant HAstV strains and for developing vaccines against this pathogenic virus.

  17. Prevalence and Genetic Diversity of Human Astroviruses in Mexican Children with Symptomatic and Asymptomatic Infections

    PubMed Central

    Méndez-Toss, Martha; Griffin, Dixie D.; Calva, Juan; Contreras, Juan F.; Puerto, Fernando I.; Mota, Felipe; Guiscafré, Héctor; Cedillo, Roberto; Muñoz, Onofre; Herrera, Ismael; López, Susana; Arias, Carlos F.

    2004-01-01

    The prevalence and type diversity of human astroviruses (HAstV) in children with symptomatic and asymptomatic infections were determined in five localities of Mexico. HAstV were detected in 4.6 (24 of 522) and 2.6% (11 of 428) of children with and without diarrhea, respectively. Genotyping of the detected strains showed that at least seven (types 1 to 4 and 6 to 8) of the eight known HAstV types circulated in Mexico between October 1994 and March 1995. HAstV types 1 and 3 were the most prevalent in children with diarrhea, although they were not found in all localities studied. HAstV type 8 was found in Mexico City, Monterrey, and Mérida; in the last it was as prevalent (40%) as type 1 viruses, indicating that this astrovirus type is more common than previously recognized. A correlation between the HAstV infecting type and the presence or absence of diarrheic symptoms was not observed. Enteric adenoviruses were also studied, and they were found to be present in 2.3 (12 of 522) and 1.4% (6 of 428) of symptomatic and asymptomatic children, respectively. PMID:14715746

  18. Examination of a plasmid-based reverse genetics system for human astrovirus.

    PubMed

    Chapellier, Benoit; Tange, Shoichiro; Tasaki, Hidetaka; Yoshida, Kazuhiro; Zhou, Yan; Sakon, Naomi; Katayama, Kazuhiko; Nakanishi, Akira

    2015-10-01

    A plasmid-based reverse genetics system for human astrovirus type 1 (HAstV1) is examined. Upon transfection into 293T cells, the plasmid vector, which harbors a HAstV1 expression cassette, expressed astroviral RNA that appeared to be capable of viral RNA replication, as indicated by the production of subgenomic RNA and capsid protein expression irrespective of the heterologous 5' ends of the transcribed RNA. Particles infectious to Caco-2 cells were made in this system; however, their infectivity was much lower than would be expected from the amount of particles apparently produced. Using Huh-7 cells as the transfection host with the aim of improving viral capsid processing for virion maturation partially restored the efficiency of infectious particle formation. Our results support the possibility that the DNA transfection process induces a cellular response that targets late, but not early, stages of HAstV1 infection.

  19. Crystal Structure of the Human Astrovirus Capsid Protein

    PubMed Central

    Toh, Yukimatsu; Harper, Justin; Dryden, Kelly A.; Yeager, Mark; Méndez, Ernesto

    2016-01-01

    ABSTRACT Human astrovirus (HAstV) is a leading cause of viral diarrhea in infants and young children worldwide. HAstV is a nonenveloped virus with a T=3 capsid and a positive-sense RNA genome. The capsid protein (CP) of HAstV is synthesized as a 90-kDa precursor (VP90) that can be divided into three linear domains: a conserved N-terminal domain, a hypervariable domain, and an acidic C-terminal domain. Maturation of HAstV requires proteolytic processing of the astrovirus CP both inside and outside the host cell, resulting in the removal of the C-terminal domain and the breakdown of the rest of the CP into three predominant protein species with molecular masses of ∼34, 27/29, and 25/26 kDa, respectively. We have now solved the crystal structure of VP9071–415 (amino acids [aa] 71 to 415 of VP90) of human astrovirus serotype 8 at a 2.15-Å resolution. VP9071–415 encompasses the conserved N-terminal domain of VP90 but lacks the hypervariable domain, which forms the capsid surface spikes. The structure of VP9071–415 is comprised of two domains: an S domain, which adopts the typical jelly-roll β-barrel fold, and a P1 domain, which forms a squashed β-barrel consisting of six antiparallel β-strands similar to what was observed in the hepatitis E virus (HEV) capsid structure. Fitting of the VP9071–415 structure into the cryo-electron microscopy (EM) maps of HAstV produced an atomic model for a continuous, T=3 icosahedral capsid shell. Our pseudoatomic model of the human HAstV capsid shell provides valuable insights into intermolecular interactions required for capsid assembly and trypsin-mediated proteolytic maturation needed for virus infectivity. Such information has potential applications in the development of a virus-like particle (VLP) vaccine as well as small-molecule drugs targeting astrovirus assembly/maturation. IMPORTANCE Human astrovirus (HAstV) is a leading cause of viral diarrhea in infants and young children worldwide. As a nonenveloped virus

  20. Statistical Modeling Efforts for Headspace Gas

    SciTech Connect

    Weaver, Brian Phillip

    2016-03-17

    The purpose of this document is to describe the statistical modeling effort for gas concentrations in WIPP storage containers. The concentration (in ppm) of CO2 in the headspace volume of standard waste box (SWB) 68685 is shown. A Bayesian approach and an adaptive Metropolis-Hastings algorithm were used.

  1. Evolutionary outcomes should inform plant breeding and transgenic approaches to drought tolerance in crop species: the importance of xylem traits

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Genomic-assisted breeding and transgenic approaches to crop improvement are presently targeting phenotypic traits that allegedly confer drought tolerance. A news feature published in Nature Biotechnology last year suggests that these efforts may not be proceeding with sufficient haste, considering t...

  2. A Rural Community and Its School: Contemporary Insights through Historical Analysis.

    ERIC Educational Resources Information Center

    Moore, Keith

    1999-01-01

    The experiences of two schoolmasters in the small Western Port Bay fishing community of Hastings (Australia) in the last century are presented to provide insights to present-day teachers about the nature of living and teaching in a rural community. The second schoolmaster did a much better job than the first in involving parents in school…

  3. Algorithm for the Retrieval of Fire Pixels from DMSP Operational Linescan System Data

    DTIC Science & Technology

    2007-11-02

    near Darjeeling , India in May 1848, British naturalist Joseph Dalton Hooker (1855) wrote that "fires, invisible by day, are seen raging all around...Washington, D.C, Final Report Volume II. Hooker , J.D., 1855: "Himalayan Journals" John Murray, London. 22 Row, L.W. Ill and Hastings, D.A., 1995

  4. The need to get smarter on smart grid projects: four Lessons

    SciTech Connect

    2010-10-15

    Significant investments are being made in gadgets and technologies, sometimes without proper analysis of the costs and potential benefits, often without much thought on how the various components of the effort would interface with one another. As often happen when things are done in great haste, there have been setbacks in a number of these initiatives, three of which are highlighted in the article.

  5. Making Art Invisible: Visual Education and the Cultural Stagnation of Neo-Liberal Rationality

    ERIC Educational Resources Information Center

    Peers, Chris

    2011-01-01

    The popularity of visual literacy may have resulted, in part, from some school authorities rushing the process of determining school curriculum. This article argues that the haste is reflective of pressure placed on educational discourse to conform to neo-liberal reforms of the sector, and is not the result of a careful and complex debate within…

  6. Their Spirits Live within Us: Aboriginal Women in Downtown Eastside Vancouver Emerging into Visibility

    ERIC Educational Resources Information Center

    Culhane, Dara

    2003-01-01

    The intersection of Main and Hastings streets--known locally as "Pain and Wastings"--marks the heart of Vancouver's inner-city neighborhood: the Downtown Eastside. Since 1997, when the City of Vancouver Health Department declared a public health emergency in response to reports that HIV infection rates among residents exceeded those…

  7. Type I Interferon Response Is Delayed in Human Astrovirus Infections

    PubMed Central

    Guix, Susana; Pérez-Bosque, Anna; Miró, Lluïsa; Moretó, Miquel; Bosch, Albert; Pintó, Rosa M.

    2015-01-01

    Type I interferon (IFN) activation and its subsequent effects are important in the response to viral infections. Here we show that human astroviruses (HAstVs), which are important agents of acute gastroenteritis in children, induce a mild and delayed IFN response upon infecting CaCo-2 cells. Although IFN-β mRNA is detected within infected cells and supernatant from infected cells show antiviral activity against the replication of other well-known IFN-sensitive viruses, these responses occur at late stages of infection once genome replication has taken place. On the other hand, HAstV replication can be partially reduced by the addition of exogenous IFN, and inhibition of IFN activation by BX795 enhances viral replication, indicating that HAstVs are IFN-sensitive viruses. Finally, different levels of IFN response were observed in cells infected with different HAstV mutants with changes in the hypervariable region of nsP1a/4, suggesting that nsP1a/4 genotype may potentially have clinical implications due to its correlation with the viral replication phenotype and the antiviral responses induced within infected cells. PMID:25837699

  8. MathBench Biology Modules: Web-Based Math for All Biology Undergraduates

    ERIC Educational Resources Information Center

    Nelson, Karen C.; Marbach-Ad, Gili; Schneider, Katie; Thompson, Katerina V.; Shields, Patricia A.; Fagan, William F.

    2009-01-01

    Historically, biology has not been a heavily quantitative science, but this is changing rapidly (Ewing 2002; Gross 2000; Hastings and palmer 2003; Jungck 2005; Steen 2005). Quantitative approaches now constitute a key tool for modern biologists, yet undergraduate biology courses remain largely qualitative and descriptive. Although biology majors…

  9. Type I interferon response is delayed in human astrovirus infections.

    PubMed

    Guix, Susana; Pérez-Bosque, Anna; Miró, Lluïsa; Moretó, Miquel; Bosch, Albert; Pintó, Rosa M

    2015-01-01

    Type I interferon (IFN) activation and its subsequent effects are important in the response to viral infections. Here we show that human astroviruses (HAstVs), which are important agents of acute gastroenteritis in children, induce a mild and delayed IFN response upon infecting CaCo-2 cells. Although IFN-β mRNA is detected within infected cells and supernatant from infected cells show antiviral activity against the replication of other well-known IFN-sensitive viruses, these responses occur at late stages of infection once genome replication has taken place. On the other hand, HAstV replication can be partially reduced by the addition of exogenous IFN, and inhibition of IFN activation by BX795 enhances viral replication, indicating that HAstVs are IFN-sensitive viruses. Finally, different levels of IFN response were observed in cells infected with different HAstV mutants with changes in the hypervariable region of nsP1a/4, suggesting that nsP1a/4 genotype may potentially have clinical implications due to its correlation with the viral replication phenotype and the antiviral responses induced within infected cells.

  10. The Interim Superintendent: A Case Study

    ERIC Educational Resources Information Center

    Bigham, Gary; Nix, Susan J.

    2011-01-01

    Considering the vitally important role that the superintendent plays in the overall functioning and wellbeing of any school district, the filling of that position should never be done in haste. Due to the importance of this process and the time it requires, school districts often employ an interim superintendent. In this single case study, one…

  11. The Brave New World of the Interim Superintendency

    ERIC Educational Resources Information Center

    Bigham, Gary D.

    2011-01-01

    Considering the vital role the superintendent plays in the overall functioning and well-being of any school district, the filling of the top leadership post with a permanent appointment never should be done in haste. The process of advertising, reviewing applications, conducting background checks, interviewing candidates, negotiating contracts,…

  12. FT. Sam 91 Whiskey Combat Medic Medical Simulation Training Quantitative Integration Enhancement Program

    DTIC Science & Technology

    2011-07-01

    COL Patricia Hastings to LTC Paul Mayer. LTC Mayer was deployed in 2008 and replaced by COL James Signaigo. On the UPMC side, Terri Collin, PhD...knowledge. Systems, Man and Cybernetics. IEE Transactions: May/Jun 1989:19(3):462- 472. Dominguez, C.O., Hutton , R.J.B., Flach, J.M., & McKellar

  13. Effective Collaboration Among Health Care and Education Professionals: A Necessary Condition for Successful Early Intervention in Rural Areas. Making It Work in Rural Communities. A Rural Network Monograph.

    ERIC Educational Resources Information Center

    Smith-Dickson, Bonnie, Ed.; Hutinger, Patricia, Ed.

    Addressing the lack of cooperation between early intervention programs and the rural health community, this monograph presents eight papers by educators and health professionals who identify specific problems and offer solutions in the form of effective collaboration techniques and model programs. Papers by Susan Hastings and Stewart Gabel…

  14. Action Items

    ERIC Educational Resources Information Center

    Baker, Mark; Keane, Brian

    2009-01-01

    Maximizing school resources and managing a shrinking budget--these are two important items affected when a building's roofing system does not perform properly. Rather than acting in haste, school and university administrators should do what every teacher tells a student prior to answering any question: think through the research and studies to…

  15. 75 FR 65282 - Medicare and Medicaid Programs; Requirements for Long Term Care Facilities; Hospice Services

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-22

    ... skilled nursing facility (SNF) in the Medicare program, or as a nursing facility (NF) in the Medicaid..., approximately 1.4 million elderly and disabled nursing home residents are receiving care in nearly 16,000... percent of older Americans die in nursing homes. (Johnson, Sandra H., Hastings Center Report, Making...

  16. Moderate Baseline Vagal Tone Predicts Greater Prosociality in Children

    ERIC Educational Resources Information Center

    Miller, Jonas G.; Kahle, Sarah; Hastings, Paul D.

    2017-01-01

    Vagal tone is widely believed to be an important physiological aspect of emotion regulation and associated positive behaviors. However, there is inconsistent evidence for relations between children's baseline vagal tone and their helpful or prosocial responses to others (Hastings & Miller, 2014). Recent work in adults suggests a quadratic…

  17. First North American record of the Palearctic Microplax albofasciata (Costa) (Hemiptera: Lygaeoidea: Oxycarenidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Microplax albofasciata (Costa), a Palearctic (mainly Mediterranean) species of the small family Oxycarenidae, is reported from California as the first record for the New World. Adults of this little-known lygaeoid bug were found in 2012 and 2013 at the Hastings Natural History Reservation in norther...

  18. LEACHING BOUNDARY IN CEMENT-BASED WASTE FORMS

    EPA Science Inventory

    Cement-based fixation systems are among the most commonly employed stabilization/solidification techniques. These cement haste mixtures, however, are vulnerable to ardic leaching solutions. Leaching of cement-based waste forms in acetic acid solutions with different acidic streng...

  19. The Experience of a Man with Severe Challenging Behaviour Following Resettlement from Hospital: A Single Case Design

    ERIC Educational Resources Information Center

    Bissell, Lianne; Phillips, Neil; Kroese, Biza Stenfert

    2005-01-01

    Carers' behaviour is thought to contribute to the development and maintenance of challenging behaviour in people with learning disabilities (Emerson et al. 1995; Hastings & Remington 1994). The present study sought to investigate the effectiveness of a behavioural intervention in the management of such problem behaviours by means of a long-term…

  20. Diffusion-weighted imaging in the prostate: an apparent diffusion coefficient comparison of half-Fourier acquisition single-shot turbo spin-echo and echo planar imaging.

    PubMed

    Babourina-Brooks, Ben; Cowin, Gary J; Wang, Deming

    2012-02-01

    Prostate cancer detection using diffusion-weighted imaging is highly affected by the accuracy of the apparent diffusion coefficient (ADC) values in an image. Echo planar imaging (EPI) is a fast sequence commonly used for diffusion imaging but has inherent magnetic susceptibility and chemical shift artefacts associated. A diffusion sequence that is less affected by these artefacts is therefore advantageous. The half-Fourier acquisition single-shot turbo spin-echo (HASTE) sequence was chosen. The diffusion sequences were compared in image quality, repeatability of the ADC value and the effect on the ADC value with varied b values. Eight volunteers underwent three scans of each sequence, on a 1.5-T Siemens system, using b values of 0, 150, 300, 450, 600, 750, 900 and 1000 s/mm(2). ADC maps were created to address the reproducibility of the ADC value when using two b values compared to eight b values. The ADC value using all b values with the HASTE sequence gave the best performance in all tested categories. Both sequences gave significantly different ADC mean values for two b values compared to when using eight b values (P<.05) suggesting larger error is present when using two b values. HASTE was shown to be an improvement over EPI in terms of repeatability, signal variation within a region of interest and standard deviation over the volunteer set. The improved accuracy of the ADC value in the HASTE sequence makes it potentially a more sensitive tumor detection technique.

  1. Bayesian Estimation of Multidimensional Item Response Models. A Comparison of Analytic and Simulation Algorithms

    ERIC Educational Resources Information Center

    Martin-Fernandez, Manuel; Revuelta, Javier

    2017-01-01

    This study compares the performance of two estimation algorithms of new usage, the Metropolis-Hastings Robins-Monro (MHRM) and the Hamiltonian MCMC (HMC), with two consolidated algorithms in the psychometric literature, the marginal likelihood via EM algorithm (MML-EM) and the Markov chain Monte Carlo (MCMC), in the estimation of multidimensional…

  2. Extended Mixed-Efects Item Response Models with the MH-RM Algorithm

    ERIC Educational Resources Information Center

    Chalmers, R. Philip

    2015-01-01

    A mixed-effects item response theory (IRT) model is presented as a logical extension of the generalized linear mixed-effects modeling approach to formulating explanatory IRT models. Fixed and random coefficients in the extended model are estimated using a Metropolis-Hastings Robbins-Monro (MH-RM) stochastic imputation algorithm to accommodate for…

  3. The Effect of an Integrative Parent Education Program on Quality of Life for Families of Children with an Autism Spectrum Disorder

    ERIC Educational Resources Information Center

    White, Caroline Jane

    2010-01-01

    Families of children with an Autism Spectrum Disorder (ASD) exhibit decreases in cohesion and adaptability, increased social isolation (Higgins et al., 2005), higher levels of marital dissatisfaction (Hastings et al., 2005), and overall disruption to daily life (Bristol et al., 1988). Research has provided evidence of higher levels of stress,…

  4. 2. AERIAL VIEW SHOWING AQUEDUCT RIGHTOFWAY PASSING OVER RAILROAD LINE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. AERIAL VIEW SHOWING AQUEDUCT RIGHT-OF-WAY PASSING OVER RAILROAD LINE FROM STONE QUARRY. TRACKS ARE GONE BUT RIGHT-OF-WAY IS STILL VISIBLE. - Old Croton Aqueduct, Quarry Railroad Bridge, Aqueduct Lane at Williams Street, Hastings-on-Hudson, Westchester County, NY

  5. Stochastic Approximation Methods for Latent Regression Item Response Models

    ERIC Educational Resources Information Center

    von Davier, Matthias; Sinharay, Sandip

    2010-01-01

    This article presents an application of a stochastic approximation expectation maximization (EM) algorithm using a Metropolis-Hastings (MH) sampler to estimate the parameters of an item response latent regression model. Latent regression item response models are extensions of item response theory (IRT) to a latent variable model with covariates…

  6. "Reading" Mixed Methods Research: Contexts for Criticism

    ERIC Educational Resources Information Center

    Freshwater, Dawn

    2007-01-01

    Health and social care researchers, in their haste to "belong" to academia, have adopted the system of mixed methodology research, overestimating its ability to reveal the truth and occasionally imprisoning their thought in one system. In this article, some of the assumptions underpinning mixed methodology research and its discourse are subjected…

  7. Stochastic Approximation Methods for Latent Regression Item Response Models. Research Report. ETS RR-09-09

    ERIC Educational Resources Information Center

    von Davier, Matthias; Sinharay, Sandip

    2009-01-01

    This paper presents an application of a stochastic approximation EM-algorithm using a Metropolis-Hastings sampler to estimate the parameters of an item response latent regression model. Latent regression models are extensions of item response theory (IRT) to a 2-level latent variable model in which covariates serve as predictors of the…

  8. The Teaching of Ethics. Vol. 1-9.

    ERIC Educational Resources Information Center

    1980

    The state of ethics teaching at the undergraduate and professional school levels is examined in these comprehensive monographs sponsored by the Institute of Society, Ethics and the Life Sciences/The Hastings Center. "The Teaching of Ethics in Higher Education (I)" encompasses: (1) the number and extent of courses in ethics, (2) the status and…

  9. Suggested Methods and Standards for Testing and Verification of Electromagnetic Buried Object Detectors

    DTIC Science & Technology

    1990-03-01

    Hasted, J. B. Aqueous dielectrics. London: Chapman and Hall; 1973. 302 p. [2.5] Dukhin, S. S. Dielectric properties of disperse systems, in Matijevic ...1985; Vol. CE-23; 1: 35-46. Dukhin, S. S. Dielectric properties of disperse systems in Matijevic , E. Surface and colloid science. E., ed. New York, NY

  10. Summary of Higher Education Accountability Statutes in Other States. OP/04-04

    ERIC Educational Resources Information Center

    California Postsecondary Education Commission, 2004

    2004-01-01

    The Public Law Research Institute at the University of California Hastings College of the Law, with whom the California Postsecondary Education Commission (CPEC) forged a partnership to research, analyze, and make sound recommendations regarding an accountability structure, provides an excellent opportunity for CPEC regarding federal and state…

  11. Analyzing the Participatory Repertoire of a U.S. Educated EFL Teacher in Saudi Arabia

    ERIC Educational Resources Information Center

    Lee-Johnson, Yin Lam

    2016-01-01

    The KSA has become a popular country for Americans to work as an EFL teacher in the recent years because of the payment and cultural experience (Hastings, 2012). Due to the wide social distance between the KSA and USA, the teachers had to adapt to the expectation and become legitimate participants (Lave and Wenger, 1991) in the local communities.…

  12. Military Review. Volume 91, Number 3, May-June 2011

    DTIC Science & Technology

    2011-06-01

    REVIEW unexamined haste.10 An article in Newsweek in September 2009 went so far as to categorize the drones as “weapons porn .”11 This view of surgical... Porn : The Greatest, Weirdest, Coolest Hardware in the American Arsenal,” Newsweek, 23 September 2009, <http://www.newsweek. com/id/215823>. 12. Kathy

  13. The Psychometric Properties of the Difficult Behavior Self-Efficacy Scale

    ERIC Educational Resources Information Center

    Oh, Hyun-Kyoung; Kozub, Francis M.

    2010-01-01

    The study was designed to estimate the psychometric properties of Hastings and Brown's (2002a) Difficult Behavior Self-efficacy Scale. Participants were two samples of physical educators teaching in Korea (n = 229) and the United States (U.S.; n = 139). An initial translation of the questionnaire to Korean and pilot study were conducted along with…

  14. Bayesian Analysis of Nonlinear Structural Equation Models with Nonignorable Missing Data

    ERIC Educational Resources Information Center

    Lee, Sik-Yum

    2006-01-01

    A Bayesian approach is developed for analyzing nonlinear structural equation models with nonignorable missing data. The nonignorable missingness mechanism is specified by a logistic regression model. A hybrid algorithm that combines the Gibbs sampler and the Metropolis-Hastings algorithm is used to produce the joint Bayesian estimates of…

  15. A Code Division Multiple Access Communication System for the Low Frequency Band.

    DTIC Science & Technology

    1983-04-01

    at the atmos- pheric noise term nA(t). 2.3 Atmospheric Noise LF atmospheric noise is predominantly generated by lightning - strokes . This noise has...T) (j (w (T)/2)J (wR (T)/2)) Ndt (3.66) 0 Equations (3.58) through (3.66) could be used to compare systems employing orthogonal signalling sets to

  16. Comparing Three Estimation Methods for the Three-Parameter Logistic IRT Model

    ERIC Educational Resources Information Center

    Lamsal, Sunil

    2015-01-01

    Different estimation procedures have been developed for the unidimensional three-parameter item response theory (IRT) model. These techniques include the marginal maximum likelihood estimation, the fully Bayesian estimation using Markov chain Monte Carlo simulation techniques, and the Metropolis-Hastings Robbin-Monro estimation. With each…

  17. The reliability of a heat acclimation state test prescribed from metabolic heat production intensities.

    PubMed

    Willmott, A G B; Hayes, M; Dekerle, J; Maxwell, N S

    2015-10-01

    Acclimation state indicates an individual's phenotypic response to a thermally stressful environment, where changes in heat dissipation capacity are determined during a heat acclimation state test (HAST). Variations in thermoregulatory and sudomotor function are reported while exercising at intensities relative to maximal oxygen uptake. This inter-individual variation is not true when intensity is prescribed to elicit a fixed rate of metabolic heat production (Ḣprod). This study investigated the reliability of peak Tre and two composite measures (sweat gain and sweat setpoint) derived from indices of thermosensitivity during a HAST prescribed from Ḣprod intensities. Fourteen participants (mean±SD; age 23±3 years, stature 174±7cm, body mass 75.0±9.4kg, body surface area 1.9±0.1m(2), peak oxygen consumption [V̇O2peak] 3.49±0.53Lmin(-1)) completed a lactate threshold-V̇O2peak test and two duplicate Ḣprod HASTs on a cycle ergometer. The HAST consisted of three, 30-min periods of exercise at fixed Ḣprod intensities relative to body mass (3, 4.5 and 6Wkg(-1)), within hot dry conditions (44.7±1.8°C and 18.1±4.7% relative humidity). Peak Tre (38.20±0.36 vs. 38.16±0.42°C, p=0.54), sweat setpoint (36.76±0.34 and 36.79±0.38°C, p=0.68) and sweat gain (0.37±0.14 and 0.40±0.18gs(-1)°C(-1), p=0.40) did not differ between HASTs. Typical error of measurement (TEM), coefficient variation (CV) and intra-class coefficient of correlation (ICC) were 0.19°C, 0.5% and 0.80 for peak Tre, 0.21°C, 0.6% and 0.65 for sweat setpoint and 0.09gs(-1)°C(-1), 28% and 0.68 for sweat gain, respectively. The use of fixed Ḣprod intensities relative to body mass is a reliable method for measuring Tre and ascertaining sweat setpoint during a HAST, whereas, sweat gain displays greater variability. A Ḣprod HAST appears sufficiently reliable for quantifying heat acclimation state, where TEM in peak Tre and sweat setpoint are small enough to identify physiologically

  18. Molecular epidemiology of enteric viruses in patients with acute gastroenteritis in Aichi prefecture, Japan, 2008/09-2013/14.

    PubMed

    Nakamura, Noriko; Kobayashi, Shinichi; Minagawa, Hiroko; Matsushita, Tadashi; Sugiura, Wataru; Iwatani, Yasumasa

    2016-07-01

    Acute gastroenteritis is a critical infectious disease that affects infants and young children throughout the world, including Japan. This retrospective study was conducted from September 2008 to August 2014 (six seasons: 2008/09-2013/14) to investigate the incidence of enteric viruses responsible for 1,871 cases of acute gastroenteritis in Aichi prefecture, Japan. Of the 1,871 cases, 1,100 enteric viruses were detected in 978 samples, of which strains from norovirus (NoV) genogroup II (60.9%) were the most commonly detected, followed by strains of rotavirus A (RVA) (23.2%), adenovirus (AdV) type 41 (8.2%), sapovirus (SaV) (3.6%), human astrovirus (HAstV) (2.8%), and NoV genogroup I (1.3%). Sequencing of the NoV genogroup II (GII) strains revealed that GII.4 was the most common genotype, although four different GII.4 variants were also identified. The most common G-genotype of RVA was G1 (63.9%), followed by G3 (27.1%), G2 (4.7%) and G9 (4.3%). Three genogroups of SaV strains were found: GI (80.0%), GII (15.0%), and GV (5.0%). HAstV strains were genotyped as HAstV-1 (80.6%), HAstV-8 (16.1%), and HAstV-3 (3.2%). These results show that NoV GII was the leading cause of sporadic acute viral gastroenteritis, although a variety of enteric viruses were detected during the six-season surveillance period.

  19. Foraging patterns of acorn woodpeckers (Melanerpes formicivorus) on valley oak (Quercus lobata Née) in two California oak savanna-woodlands.

    PubMed

    Scofield, Douglas G; Alfaro, Victor Ryan; Sork, Victoria L; Grivet, Delphine; Martinez, Edith; Papp, Jeannette; Pluess, Andrea R; Koenig, Walter D; Smouse, Peter E

    2011-05-01

    Landscape characteristics and social behavior can affect the foraging patterns of seed-dependent animals. We examine the movement of acorns from valley oak (Quercus lobata) trees to granaries maintained by acorn woodpeckers (Melanerpes formicivorus) in two California oak savanna-woodlands differing in the distribution of Q. lobata within each site. In 2004, we sampled Q. lobata acorns from 16 granaries at Sedgwick Reserve in Santa Barbara County and 18 granaries at Hastings Reserve in Monterey County. Sedgwick has lower site-wide density of Q. lobata than Hastings as well as different frequencies of other Quercus species common to both sites. We found acorn woodpeckers foraged from fewer Q. lobata seed source trees (K(g) = 4.1 ± 0.5) at Sedgwick than at Hastings (K(g) = 7.6 ± 0.6) and from fewer effective seed sources (N(em)* = 2.00 and 5.78, respectively). The differences between sites are due to a greater number of incidental seed sources used per granary at Hastings than at Sedgwick. We also found very low levels of seed source sharing between adjacent granaries, indicating that territoriality is strong at both sites and that each social group forages on its own subset of trees. We discovered an interesting spatial pattern in the location of granaries. At Sedgwick, acorn woodpeckers situated their granaries within areas of higher-than-average tree density, while at Hastings, they placed them within areas of lower-than-average tree density, with the outcome that granaries at the two sites were located in areas of similar valley oak density. Our results illustrate that landscape characteristics might influence the number of trees visited by acorn woodpeckers and the locations of territories, while woodpecker social behavior, such as territoriality, shapes which trees are visited and whether they are shared with other social groups.

  20. Emerging trends in the epidemiology of human astrovirus infection among infants, children and adults hospitalized with acute watery diarrhea in Kolkata, India.

    PubMed

    Pativada, Madhusudhan; Nataraju, Seegekote Mariyappa; Ganesh, Balasubramanian; Rajendran, Krishnan; Ramamurthy, Thandavarayan; Ganguly, Sandipan; Bhattacharya, Mihir Kumar; Ghosh, Mrinmoy; Kobayashi, Nobumichi; Krishnan, Triveni

    2012-12-01

    Human astroviruses (HAstVs) have now emerged as another common cause of non-bacterial acute gastroenteritis (AGE) in humans worldwide. This study investigated the epidemiology and genetic diversity of human astrovirus strains circulating among infants, younger children (up to 6 years), older children and adolescents (>6-17 years) and adults (18 years and above) hospitalized for diarrhea and their role in AGE in Kolkata, India. A total of 2535 fecal samples were screened for the presence of known enteric viral, bacterial and parasitic etiologies by conventional microbiological assays and molecular methods. The overall incidences of sole or mixed infection of HAstV with known enteric viral, bacterial and parasitic pathogens were detected in 60 cases (2.4%) among all age groups. The clinical symptoms of astrovirus-associated acute watery diarrhea cases were recorded for all sole and mixed infection cases. A high number of sole (n = 13/60 [21.7%]) and mixed infection cases (n = 22/60 [36.7%]) were observed in adults (18 years old or more). Considering all age groups, 18 sole infection cases (n = 18/60 [30%]) and 42 mixed infection cases (n = 42/60 [70%]) with Rotavirus (n = 11/25 [44%]), Vibrio cholerae O1 (n = 6/24 [25%]) Cryptosporidium spp and Giardia lamblia (n = 5/13 [38.4%]) were observed. Further, eleven HAstV samples from infants and children (up to 6 years), children and adolescents (>6-17 years) and adults (18 years and above) were analyzed for their sequences of overlap region between ORF1b (RdRp) and ORF2 (capsid). Among these, ten strains were found to have close genetic relatedness to the Japanese strain HAstV_G1 [AB009985]. Additionally, the IDH2211 Kolkata strain showed a close genetic match with the Thai HAstV_G3 strain [EU363889]. Our study reports show that HAstVs as the sole agent and as mixed infection with other known enteric viral, bacterial, parasitic pathogens are also responsible for AGE among infants, children, adolescents and adults in

  1. Learning about Teaching.

    PubMed

    Kaebnick, Gregory E

    2014-09-01

    There are three broad themes in this issue of the Hastings Center Report. First, a special report published as a supplement to the issue addresses the medical and health policy issues faced by lesbian, gay, bisexual, and transgender patients. Inside the issue, the two articles take up questions about how caregivers may justify a refusal to provide a medical service that a patient has requested. The issue also contains a set of essays that have emerged from a collaborative effort by The Hastings Center and the Presidential Commission for the Study of Bioethical Issues to promote scholarly engagement with the practical problem of teaching caregivers, researchers, scientists, and others to address bioethical problems. What appears here is the first installment of a series that will appear in the pages of the Report well into the 2015 volume.

  2. Ethical and policy issues in rehabilitation medicine.

    PubMed

    Caplan, Arthur L; Callahan, Daniel; Haas, Janet

    1987-08-01

    The field of medical rehabilitation is relatively new.... Until recently, the ethical problems of this new field were neglected. There seemed to be more pressing concerns as rehabilitation medicine struggled to establish itself, sometimes in the face of considerable skepticism or hostility. There also seemed no pressing moral questions of the kind and intensity to be encountered, say, in high-technology acute care medicine or genetic engineering.... Those in biomedical ethics could and did easily overlook the quiet, less obtrusive issues of rehabilitation.... The Hastings Center set out in 1985 to rectify that situation.... To explore the issues, the Center assembled a group of practitioners in the field, Hastings Center staff members, and individuals experienced in other areas of medical ethics.... The report that follows was written by Arthur Caplan and Daniel Callahan, assisted by Dr. Janet Haas of the Moss Rehabilitation Hospital in Philadelphia....

  3. LETTER TO THE EDITOR: No sliding in time

    NASA Astrophysics Data System (ADS)

    Shtengel, Kirill; Nayak, Chetan; Bishara, Waheb; Chamon, Claudio

    2005-09-01

    In this letter, we analyse the following apparent paradox: as has been recently proved by Hastings (2004 Phys. Rev. 69 104431), under a general set of conditions, if a local Hamiltonian has a spectral gap above its (unique) ground state (GS), all connected equal-time correlation functions of local operators decay exponentially with distance. On the other hand, statistical mechanics provides us with examples of 3D models displaying so-called sliding phases (O'Hern et al 1999 Phys. Rev. Lett. 83 2745) which are characterized by the algebraic decay of correlations within 2D layers and exponential decay in the third direction. Interpreting this third direction as time would imply a gap in the corresponding (2+1)D quantum Hamiltonian which would seemingly contradict Hastings' theorem. The resolution of this paradox lies in the non-locality of such a quantum Hamiltonian.

  4. JPRS Report, Soviet Union, EKO: Economics & Organization of Industrial Production, No. 9, September 1987.

    DTIC Science & Technology

    2007-11-02

    manifesting initiatives and mastery is more attractive than high earnings. Publications about the cooperatives that have been cre- ated suggest to...impoverished segments of the population, not hav- ing a high level of political culture, are more quickly subject to propaganda of the next historical...caused by "leftist haste" in questions of cooperation. In European socialist countries with a traditionally high cultural life (for example, the GDR

  5. Flood Control Project Lac Qui Parle, Emergency Plan

    DTIC Science & Technology

    1988-10-01

    ncn operations Center .. Provides a 24-hour telephone contact with the District Office. Responsible for keeping the Dam Safety Officer, the Commander...situations. Also contact for matters involving national security, disasters, mobilization or NwS flood forecasts. Center wilt contact Dam Safety Officer, the...Commaander/District Engineer and NCD. District Emergency Operations Center (612)220-0208 Contact Hastings David Christenson, Chief, Emergency

  6. ’Stinger under Armor:’ An Analysis of Alternatives

    DTIC Science & Technology

    1990-01-01

    Military Effectiveness 1914-1945," Lieutenant General John H. Cushman, U.S. Army, Retired, wrote: Our histories tell us that -- whether it be through...Air Defense 1988- 1989. Surrey, U.K.: Jane’s Information Group, 1988. Cushman, John H. Challenge & Response: Military Effectiveness 1914-1945...Mideast Research, 1980. English, John A. On infintry. New York: Praeger Publishers, 1984. Hastings, Max, and Simon Jenkins. The Battle For the Falklands

  7. Next-Generation Sequencing for Diagnosis and Tailored Therapy: A Case Report of Astrovirus-Associated Progressive Encephalitis.

    PubMed

    Frémond, M-L; Pérot, P; Muth, E; Cros, G; Dumarest, M; Mahlaoui, N; Seilhean, D; Desguerre, I; Hébert, C; Corre-Catelin, N; Neven, B; Lecuit, M; Blanche, S; Picard, C; Eloit, M

    2015-09-01

    A boy with X-linked agammaglobulinemia experienced progressive global motor decline, cerebellar syndrome, and epilepsy. All standard polymerase chain reactions for neurotropic viruses were negative on cerebrospinal fluid and brain biopsy. Next-generation sequencing allowed fast identification of a new astrovirus strain (HAstV-VA1/HMO-C-PA), which led to tailor the patient's treatment, with encouraging clinical monitoring over 1 year.

  8. Assessment of gastroenteric viruses from wastewater directly discharged into Uruguay River, Uruguay.

    PubMed

    Victoria, M; Tort, L F L; García, M; Lizasoain, A; Maya, L; Leite, J P G; Miagostovich, M P; Cristina, J; Colina, R

    2014-06-01

    The aim of this study was to assess the viral contamination of group A rotavirus (RVA), norovirus (NoV), and human astrovirus (HAstV) in sewage directly discharged into Uruguay River and to characterize RVA genotypes circulating in Uruguay. For this purpose, sewage samples (n = 96) were collected biweekly from March 2011 to February 2012 in four Uruguayan cities: Bella Unión, Salto, Paysandú, and Fray Bentos. Each sample was concentrated by ultracentrifugation method. Qualitative and quantitative RT-PCR for RVA, NoV, and HAstV were performed. A wide dissemination of gastroenteric viruses was observed in the sewage samples analyzed with 80% of positivity, being NoV (51%) the most frequently detected followed by RVA with a frequency of 49% and HAstV with 45%. Genotypes of RVA were typed using multiplex semi-nested RT-PCR as follows: P[8] (n = 15), P[4] (n = 8), P[10] (n = 1), P[11] (n = 1), G2 (n = 29), and G3 (n = 2). The viral load ranged from 10(3) to 10(7) genomic copies/liter, and they were detected roughly with the same frequency in all participant cities. A peak of RVA and HAstV detection was observed in colder months (June to September), whereas no seasonality was observed for NoV. This study demonstrates for the first time, the high degree of gastroenteric viral contamination in the country; highlighting the importance of developing these analyses as a tool to determine the viral contamination in this hydrographic boundary region used by the local populations for recreation and consumption, establishing an elevated risk of gastroenteric diseases for human health.

  9. Monte-Carlo Inversion of Travel-Time Data for the Estimation of Weld Model Parameters

    NASA Astrophysics Data System (ADS)

    Hunter, A. J.; Drinkwater, B. W.; Wilcox, P. D.

    2011-06-01

    The quality of ultrasonic array imagery is adversely affected by uncompensated variations in the medium properties. A method for estimating the parameters of a general model of an inhomogeneous anisotropic medium is described. The model is comprised of a number of homogeneous sub-regions with unknown anisotropy. Bayesian estimation of the unknown model parameters is performed via a Monte-Carlo Markov chain using the Metropolis-Hastings algorithm. Results are demonstrated using simulated weld data.

  10. The Effect of Anisotropic Scatter on Atmospheric Neutron Transport

    DTIC Science & Technology

    2015-03-26

    ingestion and use of cross-section data from ENDF file extractions. These cross sections along with atmospheric composition data are used by HASTE...åå [2.15] where l is the total number of species in the atmosphere , n is the number of elements in the atmosphere , im is the number of isotopes ...of element i, , isotope air kf is the atmospheric fraction of isotope k, and so on. Based upon how the atmospheric concentrations are specified

  11. Astrovirus VA1/HMO-C: An Increasingly Recognized Neurotropic Pathogen in Immunocompromised Patients

    PubMed Central

    Brown, Julianne R.; Morfopoulou, Sofia; Hubb, Jonathan; Emmett, Warren A.; Ip, Winnie; Shah, Divya; Brooks, Tony; Paine, Simon M. L.; Anderson, Glenn; Virasami, Alex; Tong, C. Y. William; Clark, Duncan A.; Plagnol, Vincent; Jacques, Thomas S.; Qasim, Waseem; Hubank, Mike; Breuer, Judith

    2015-01-01

    Background. An 18-month-old boy developed encephalopathy, for which extensive investigation failed to identify an etiology, 6 weeks after stem cell transplant. To exclude a potential infectious cause, we performed high-throughput RNA sequencing on brain biopsy. Methods. RNA-Seq was performed on an Illumina Miseq, generating 20 million paired-end reads. Nonhost data were checked for similarity to known organisms using BLASTx. The full viral genome was sequenced by primer walking. Results. We identified an astrovirus, HAstV-VA1/HMO-C-UK1(a), which was highly divergent from human astrovirus (HAstV 1–8) genotypes, but closely related to VA1/HMO-C astroviruses, including one recovered from a case of fatal encephalitis in an immunosuppressed child. The virus was detected in stool and serum, with highest levels in brain and cerebrospinal fluid (CSF). Immunohistochemistry of the brain biopsy showed positive neuronal staining. A survey of 680 stool and 349 CSF samples identified a related virus in the stool of another immunosuppressed child. Conclusions. The discovery of HAstV-VA1/HMO-C-UK1(a) as the cause of encephalitis in this case provides further evidence that VA1/HMO-C viruses, unlike HAstV 1–8, are neuropathic, particularly in immunocompromised patients, and should be considered in the differential diagnosis of encephalopathy. With a turnaround from sample receipt to result of <1 week, we confirm that RNA-Seq presents a valuable diagnostic tool in unexplained encephalitis. PMID:25572899

  12. New applications of Schrödinger type inequalities to the existence and uniqueness of Schrödingerean equilibrium.

    PubMed

    Wang, Jianjie; Roncalver, Hugo

    2017-01-01

    As new applications of Schrödinger type inequalities appearing in Jiang (J. Inequal. Appl. 2016:247, 2016), we first investigate the existence and uniqueness of a Schrödingerean equilibrium. Next we propose a tritrophic Hastings-Powell model with two different Schrödingerean time delays. Finally, the stability and direction of the Schrödingerean Hopf bifurcation are also investigated by using the center manifold theorem and normal form theorem.

  13. Molecular Probes in Marine Ecology: Concepts, Techniques and Applications.

    DTIC Science & Technology

    1991-08-16

    bacterial Woody Hastings: bioluminescence . 20 Wed. Paul Dunlap: The lux genes in bacteria : organization, structure, and expression. 21 Thurs. Chuck...probes for microbial identification. Ken Nealson: Taxonomy physiology and distribution of marine bioluminescent bacteria . 10 Tues. Ann Bucklin: Allozymic...cuponsored with the microbiology course, the first of these being on bioluminescence and symbiosis on July 7, and the second on molecular approaches to

  14. A Method Using Epoch-Era Analysis to Identify Valuable Changeability in System Design

    DTIC Science & Technology

    2011-04-01

    2005) published a paper summarizing unifying principles behind designing for changeability ( DfC ) in engineering. In addition to covering the motivation...changeability of designs and not of the designing process. According to DfC , robustness is the ability of a system to withstand environmental changes... DfC ): Principles to enable changes in systems throughout their entire lifecycle,” Systems Engineering, vol. 8, 2005, pp. 342-359. Hastings, D.E

  15. USSR Report, Military Affairs.

    DTIC Science & Technology

    2007-11-02

    notorious questionnaire method, haste and thoughtlessness lead to sad results. For example, in one unit in the Northern Group of Forces a person...the Komsomol member and how they worried that he was military, cocky and sharp-tongued! And his shoulders were squared and his craving to dare, to...examples in this work and make a contribution to the implementation of the nation’s Food Pro- gram. This year too, working in the kolkhoz and sovkhoz

  16. Enhanced Research to Create More Jobs

    SciTech Connect

    Agnihotri, Newal, K.

    2004-03-01

    Mr. Doc Hastings, U.S. Congressman from the state of Washington is interviewed regarding various topics related to the nuclear energy picture in the US. Topics include the level of public support for nuclear energy, differences between the roles for state and federal governments, job creation, clean-up briefings, a Yucca Mountain status, a hydrogen-nuclear status, the role of nuclear energy in Kyoto protocol compliance, and the market for power plants.

  17. An Investigation of the Pareto Distribution as a Model for High Grazing Angle Clutter

    DTIC Science & Technology

    2011-03-01

    The Pareto Distribution [1-3] is named after the Italian economist Vilfredo Pareto (15 July 1848 – 19 August 1923) [4, 5], and is a power law...1980). 3. Evans, M., Hastings, N. and Peacock, B., Statistical Distributions, 3rd Edition, (Wiley, New York, 2000). 4. Bruno, G. “ Pareto , Vilfredo ” The...New Palgrave: A Dictionary of Economics, 5, 799804, 1987. 5. Cirillo, R. The Economics of Vilfredo Pareto , (Frank Cass Publishers, 1978) 6. Aban, I. B

  18. Index to USA Aviation Digest, 1991

    DTIC Science & Technology

    1992-11-01

    Aviation Digest; Nov-Dec 1991: p. 42. CIPPS SEE CIVILIAN INTEGRATION INTO THE PERSONNEL PROPONENCY SYSTEM ( CIPPS ) CIVILIAN INTEGRATION INTO THE PERSONNEL...PROPONENCY SYSTEM ( CIPPS ) Civilian integration into the Personnel Proponency System ( CIPPS ). USA Aviation Digest; Jul-Aug 1991: p. 28. CMIF SEE...HASTINGS, ROBERT T. Twenty commandments for platoon leaders. USA Aviation Digest; Mar-Apr 1991: p. 30-31. HAYES, THOMAS M. Delta models at the

  19. Freshwater Mussels (Mollusca: Bivalvia: Unionidae) of the Upper Mississippi River: Observations at Selected Sites Within the 9-Foot Navigation Channel Project for the St. Paul District, United States Army Corps of Engineers, 1977 - 1979. Volume II. Appendices.

    DTIC Science & Technology

    1980-09-10

    111 16. Vermillion River 15 >2 1)9, _: L Hastings Small Boat Harbor 16 13 -,2 IS. Prescott 17 !14 199, 19. Pine Coulee 13 15 0. Truedaie Slough 19 116...Iowa Darter E. nigrum Rafinesque, Johnny Darter Perca flavescens (Mitchill), Yellow Perch Stizostedion e-avadense (Smith), Sauger Family Sciaenidae...brailing Brail runs: positive, 0 ; negative, 14 ;total, 14 Number of square ifeet brailed: 70,000 Exhibit 15 16. Vermillion River \\Tusc’ Tha, xni

  20. Comparison of Hall Thruster Plume Expansion Model with Experimental Data

    DTIC Science & Technology

    2006-05-23

    focus of this study, is a hybrid particle- in-cell ( PIC ) model that tracks particles along an unstructured tetrahedral mesh. * Research Engineer...measurements of the ion current density profile, ion energy distributions, and ion species fraction distributions using a nude Faraday probe, retarding...Vol.37 No.1. 6 Oh, D. and Hastings, D., “Three Dimensional PIC -DSMC Simulations of Hall Thruster Plumes and Analysis for Realistic Spacecraft

  1. Comparison of Hall Thruster Plume Expansion Model with Experimental Data (Preprint)

    DTIC Science & Technology

    2006-07-01

    Cartesian mesh. AQUILA, the focus of this study, is a hybrid PIC model that tracks particles along an unstructured tetrahedral mesh. COLISEUM is capable...measurements of the ion current density profile, ion energy distributions, and ion species fraction distributions using a nude Faraday probe...Spacecraft and Rockets, Vol.37 No.1. 6 Oh, D. and Hastings, D., “Three Dimensional PIC -DSMC Simulations of Hall Thruster Plumes and Analysis for

  2. Recent Advances in Spacecraft Charging

    DTIC Science & Technology

    1994-03-08

    divergence. The with partial successes [Cohen, etal., 1981; Cohen and transverse energy gained by a diverging beam Lai, 1982; Olsen , 1985; Werner, 1988]. When...probes, J AppL Phys., Technology Conference, R.C. Olsen (ed), Naval 63, 5674-5677, 1988. Postgraduate School, Mornterey, 1989. Neubert, T., MJ...Dec., 1993. Olsen , R.C., Modification of spacecraft potentials by Wang, J. and D.E_ Hastings, Ionospheric plasma flow plasma emission, J. Spacecraft

  3. Ethics committees and cost containment.

    PubMed

    Brock, D W

    1990-01-01

    Cohen introduces a section of articles on hospital ethics committees that appears twice a year in the Hastings Center Report. Articles by Dan W. Brock, Alan R. Fleischman, Suzanne M. Mitchell and Martha S. Swartz, and Janet Fleetwood support the idea that hospital ethics committees are performing a needed service. Ethics committees have been in existence long enough, however, to begin to explore new issues and activities.

  4. Marching to a Different Drummer. Military Women in American Popular Magazines, 1975-1985.

    DTIC Science & Technology

    1985-12-30

    16 1 0Roland E . Wolseley, "Social Effects of Magazines," in Mass Media and Communication, ed. Charles S. Steinberg (New York...Military News," Journalism Quar- terly 51 (Autumn 1974): 563-69. 4 6James E . Fletcher and Philip E . Soucy, "Army Public Affairs Officer as Perceived ...pp. 28-32. 8 5Roland E . Wolseley, "Social Effects of Magazines," in Mass Media and Communication, ed. Charles S. Steinberg (New York: Hastings House

  5. de Finetti Priors using Markov chain Monte Carlo computations.

    PubMed

    Bacallado, Sergio; Diaconis, Persi; Holmes, Susan

    2015-07-01

    Recent advances in Monte Carlo methods allow us to revisit work by de Finetti who suggested the use of approximate exchangeability in the analyses of contingency tables. This paper gives examples of computational implementations using Metropolis Hastings, Langevin and Hamiltonian Monte Carlo to compute posterior distributions for test statistics relevant for testing independence, reversible or three way models for discrete exponential families using polynomial priors and Gröbner bases.

  6. de Finetti Priors using Markov chain Monte Carlo computations

    PubMed Central

    Bacallado, Sergio; Diaconis, Persi; Holmes, Susan

    2015-01-01

    Recent advances in Monte Carlo methods allow us to revisit work by de Finetti who suggested the use of approximate exchangeability in the analyses of contingency tables. This paper gives examples of computational implementations using Metropolis Hastings, Langevin and Hamiltonian Monte Carlo to compute posterior distributions for test statistics relevant for testing independence, reversible or three way models for discrete exponential families using polynomial priors and Gröbner bases. PMID:26412947

  7. Concepts for Data Collection in the Arctic

    DTIC Science & Technology

    1972-05-01

    Weather Service. NOAA, U.S. Department of Commerce , October 1970. 7. Hastings, A. D. Jr. Arctic Basin--Locations of Climatic Stations. U.S. Army Engineer...flat deck version of the ACV, known as the Voyageur , in the central Canadian Arctic. The flatbed design offers flexibility in configuring the vehicle...range of 300 miles for the Voyageur at average cruising speeds of 30 mph for full fuel capacity. In August 1971, a predecessor model of this craft (the

  8. Concepts for Data Collection in the Arctic

    DTIC Science & Technology

    1972-05-01

    Francisco/Point Barrow, January-August 1971. 6. Operations of the National Weather Service. NOAA, U.S. Department of Commerce , October 1970. 7. Hastings... Voyageur , in the central Canadian Arctic. The flatbed design offers flexibility in configuring the vehicle for multimission operation (e.g., supply...comprising working laboratories, housing, and data collection and recording facilities. The manufacturer claims a range of 300 miles for the Voyageur at

  9. Resistant starch reduces colonic and urinary p-cresol in rats fed a tyrosine-supplemented diet, whereas konjac mannan does not.

    PubMed

    Chen, Bixiao; Morioka, Sahya; Nakagawa, Tomoyuki; Hayakawa, Takashi

    2016-10-01

    The effect of resistant starch (RS) and konjac mannan (KM) to maintain and improve the large intestinal environment was compared. Wistar SPF rats were fed the following diets for 4 weeks: negative control diet (C diet), tyrosine-supplemented positive control diet (T diet), and luminacoid supplemented diets containing either high-molecular konjac mannan A (KMAT diet), low-molecular konjac mannan B (KMBT diet), high-amylose cornstarch (HAST diet), or heat-moisture-treated starch (HMTST diet). The luminacoid-fed group had an increased content of short-chain fatty acids in the cecum. HAS caused a significant decrease in p-cresol content in the cecum, whereas KM did not. Urinary p-cresol was reduced in the HAST group compared with the T group, but not the KM fed groups. Deterioration in the large intestinal environment was only improved completely in the HAST and HMTST groups, suggesting that RS is considerably more effective than KM in maintaining the large intestinal environment.

  10. Production of polyclonal antibody to a recombinant non-structural protein Nsp1a of human astrovirus.

    PubMed

    Liu, Chang; Liu, Wen-Hui; Kan, Li-Li; Li, Xin; Li, Yong-gang; Zhao, Wei

    2014-12-01

    Human astrovirus (HAstV) are important pathogens that cause acute viral diarrhea in infants. Little is known about the mechanisms of astrovirus-induced diarrhea. Previous studies have suggested that an apoptosis inducer may be encoded in the non-structural protein (nsP1a) of astrovirus and contribute to virus-induced diarrhea. To study the biological function of nsP1a and to gain further insight into nsP1a protein-host cell interactions, good quality antibodies must be produced. The nsP1agene of HAstV-1 was cloned into a bacterial expression vector Pgex-6P-1. The recombinant plasmid Pgex-6P-nsP1a was transformed into Escherichia coli BL21 (DE3) and expressed as a fusion protein that contains N-terminal GST tags. The expressed recombinant protein was purified and used as an antigen to produce an nsP1a antiserum in rabbits. ELISA was used to detect the titer of specific antibodies. Specificity activity was detected by Western blot and immunofluorescence analysis. The titer of specific antibodies was up to 1:30,000. Western blotting and immunofluorescence analysis indicated that the polyclonal antibody could recognize specifically the HAstV-1 nsP1a protein.

  11. Comparison of the kinetics of different Markov models for ligand binding under varying conditions

    SciTech Connect

    Martini, Johannes W. R.; Habeck, Michael

    2015-03-07

    We recently derived a Markov model for macromolecular ligand binding dynamics from few physical assumptions and showed that its stationary distribution is the grand canonical ensemble [J. W. R. Martini, M. Habeck, and M. Schlather, J. Math. Chem. 52, 665 (2014)]. The transition probabilities of the proposed Markov process define a particular Glauber dynamics and have some similarity to the Metropolis-Hastings algorithm. Here, we illustrate that this model is the stochastic analog of (pseudo) rate equations and the corresponding system of differential equations. Moreover, it can be viewed as a limiting case of general stochastic simulations of chemical kinetics. Thus, the model links stochastic and deterministic approaches as well as kinetics and equilibrium described by the grand canonical ensemble. We demonstrate that the family of transition matrices of our model, parameterized by temperature and ligand activity, generates ligand binding kinetics that respond to changes in these parameters in a qualitatively similar way as experimentally observed kinetics. In contrast, neither the Metropolis-Hastings algorithm nor the Glauber heat bath reflects changes in the external conditions correctly. Both converge rapidly to the stationary distribution, which is advantageous when the major interest is in the equilibrium state, but fail to describe the kinetics of ligand binding realistically. To simulate cellular processes that involve the reversible stochastic binding of multiple factors, our pseudo rate equation model should therefore be preferred to the Metropolis-Hastings algorithm and the Glauber heat bath, if the stationary distribution is not of only interest.

  12. Development of a multiplex PCR assay to detect gastroenteric pathogens in the feces of Mexican children.

    PubMed

    Tolentino-Ruiz, R; Montoya-Varela, D; García-Espitia, M; Salas-Benito, M; Gutiérrez-Escolano, A; Gómez-García, C; Figueroa-Arredondo, P; Salas-Benito, J; De Nova-Ocampo, M

    2012-10-01

    Acute gastroenteritis (AGE) is a major cause of childhood morbidity and mortality worldwide; the etiology of AGE includes viruses, bacteria, and parasites. A multiplex PCR assay to simultaneously identify human Astrovirus (HAstV), Calicivirus (HuCVs), Entamoeba histolytica (E. histolytica), and enteroinvasive Escherichia coli (EIEC) in stool samples is described. A total of 103 samples were individually analyzed by ELISA (enzyme-linked immunosorbent assays) and RT-PCR/PCR. HAstV and HuCVs were detected in four out of 103 samples (3.8 %) by RT-PCR, but ELISAs found only one sample as positive for HuCVs (2.5 %). E. histolytica was identified in two out of 19 samples (10.5 %) and EIEC in 13 out of 20 samples (70 %) by PCR, and all PCR products were sequenced to verify their identities. Our multiplex PCR results demonstrate the simultaneous amplification of different pathogens such as HAstV, EIEC, and E. histolytica in the same reaction, though the HuCVs signal was weak in every replicate. Regardless, this multiplex PCR protocol represents a novel tool for the identification of distinct pathogens and may provide support for the diagnosis of AGE in children.

  13. Implementation and evaluation of a new workflow for registration and segmentation of pulmonary MRI data for regional lung perfusion assessment.

    PubMed

    Böttger, T; Grunewald, K; Schöbinger, M; Fink, C; Risse, F; Kauczor, H U; Meinzer, H P; Wolf, Ivo

    2007-03-07

    Recently it has been shown that regional lung perfusion can be assessed using time-resolved contrast-enhanced magnetic resonance (MR) imaging. Quantification of the perfusion images has been attempted, based on definition of small regions of interest (ROIs). Use of complete lung segmentations instead of ROIs could possibly increase quantification accuracy. Due to the low signal-to-noise ratio, automatic segmentation algorithms cannot be applied. On the other hand, manual segmentation of the lung tissue is very time consuming and can become inaccurate, as the borders of the lung to adjacent tissues are not always clearly visible. We propose a new workflow for semi-automatic segmentation of the lung from additionally acquired morphological HASTE MR images. First the lung is delineated semi-automatically in the HASTE image. Next the HASTE image is automatically registered with the perfusion images. Finally, the transformation resulting from the registration is used to align the lung segmentation from the morphological dataset with the perfusion images. We evaluated rigid, affine and locally elastic transformations, suitable optimizers and different implementations of mutual information (MI) metrics to determine the best possible registration algorithm. We located the shortcomings of the registration procedure and under which conditions automatic registration will succeed or fail. Segmentation results were evaluated using overlap and distance measures. Integration of the new workflow reduces the time needed for post-processing of the data, simplifies the perfusion quantification and reduces interobserver variability in the segmentation process. In addition, the matched morphological data set can be used to identify morphologic changes as the source for the perfusion abnormalities.

  14. A novel method of real-time reverse-transcription loop-mediated isothermal amplification developed for rapid and quantitative detection of human astrovirus.

    PubMed

    Wei, Haiyan; Zeng, Jing; Deng, Congliang; Zheng, Chengzhong; Zhang, Ximeng; Ma, Dan; Yi, Yong

    2013-03-01

    A one-step, real-time reverse-transcription loop-mediated isothermal amplification (rRT-LAMP) method targeting the 5' end of the capsid gene for rapid and quantitative detection of human astrovirus serotype 1 (HAstV 1) was developed. The assay is highly sensitive and comparable to real-time RT-PCR (rRT-PCR), with a detection limit of ∼100 RNA copies per assay. The specificity of the method was validated by the absence of any cross-reaction with RNA samples of HAstV 2-8 and other gastroenteritis viruses, followed by nucleotide sequencing of the amplified product. Fecal specimens (n=120) obtained from children under five years of age with gastroenteritis were tested by rRT-LAMP, rRT-PCR and transmission electron microscopy (TEM). Six (5%) of these samples were determined to be positive by both rRT-LAMP and rRT-PCR assay, and these two nucleic acid amplification methods resulted in a 200% increase in detection rates for HAstV infection compared with TEM alone. Furthermore, the rRT-LAMP assay is much more rapid than rRT-PCR and generates results in less than 20min for positive samples. The quantitation of viral load in stool specimens was determined from the standard curve plot of time-of-positivity versus initial RNA concentration. Most viral loads were determined to be within the range of 10(5)-10(8) copies. The results highlight the significance of the rapid rRT-LAMP method as a diagnostic and routine screening tool for the analysis of stool samples in hospital laboratories.

  15. The Anatomy and Phylogenetic Relationships of “Pelorosaurus“ becklesii (Neosauropoda, Macronaria) from the Early Cretaceous of England

    PubMed Central

    Upchurch, Paul; Mannion, Philip D.; Taylor, Michael P.

    2015-01-01

    The sauropod dinosaur “Pelorosaurus” becklesii was named in 1852 on the basis of an associated left humerus, ulna, radius and skin impression from the Early Cretaceous (Berriasian-Valanginian) Hastings Beds Group, near Hastings, East Sussex, southeast England, United Kingdom. The taxonomy and nomenclature of this specimen have a complex history, but most recent workers have agreed that “P.” becklesii represents a distinct somphospondylan (or at least a titanosauriform) and is potentially the earliest titanosaur body fossil from Europe or even globally. The Hastings specimen is distinct from the approximately contemporaneous Pelorosaurus conybeari from Tilgate Forest, West Sussex. “P.” becklesii can be diagnosed on the basis of five autapomorphies, such as: a prominent anteriorly directed process projecting from the anteromedial corner of the distal humerus; the proximal end of the radius is widest anteroposteriorly along its lateral margin; and the unique combination of a robust ulna and slender radius. The new generic name Haestasaurus is therefore erected for “P.” becklesii. Three revised and six new fore limb characters (e.g. the presence/absence of condyle-like projections on the posterodistal margin of the radius) are discussed and added to three cladistic data sets for Sauropoda. Phylogenetic analysis confirms that Haestasaurus becklesii is a macronarian, but different data sets place this species either as a non-titanosauriform macronarian, or within a derived clade of titanosaurs that includes Malawisaurus and Saltasauridae. This uncertainty is probably caused by several factors, including the incompleteness of the Haestasaurus holotype and rampant homoplasy in fore limb characters. Haestasaurus most probably represents a basal macronarian that independently acquired the robust ulna, enlarged olecranon, and other states that have previously been regarded as synapomorphies of clades within Titanosauria. There is growing evidence that basal

  16. USAF Advanced Terrestrial Energy Study. Volume 4. Analysis, Data, and Bibliography.

    DTIC Science & Technology

    1983-04-01

    LOCATION CONSTRAINTS Constraints Effects Remarks 1. Water Requirements 2. Manning Requirements Fully automated 3. Fuel Availability and 0 Hast be located...THIS DEP IN ITICAN BUILDS ON THE PMASE I bTUOT THROUGH ITS FOLUS ON A LOAL-DERIVED LIQJUID FUELED. ൖ." FIRIN& TEMPERATURE. WATER -COOLED GAS TURBINE...THE SYSTEM COWSISTS NA INLY. OF HIGM-SEMIRATU14E. WATER -COOLED GAS TURSBINES THAT BURN COAL-CERi WEB GAS PFL. AD A STEAM BOTTOMING CYCLE WITH4 ONE

  17. Early Pottery Making in Northern Coastal Peru. Part III: Mössbauer Study of Sicán Pottery

    NASA Astrophysics Data System (ADS)

    Shimada, I.; Häusler, W.; Hutzelmann, T.; Riederer, J.; Wagner, U.

    2003-09-01

    Sicán blackware from a 1000-year old elite tomb at Huaca Loro was characterised by neutron activation analysis, optical thin-section microscopy, X-ray diffraction and Mössbauer spectroscopy. A number of blackware fragments from the later site of Puerto Pobre (ca. AD 1460-1550) were included in the analysis for comparison and found to be of different origin. The black surface of the specimens from Huaca Loro is mostly due to carbon deposition during firing in a reducing environment. Part of the pottery was merely dried at temperatures below 400°C, perhaps because it was made in haste for funeral use.

  18. Eutrophication control and the fallacy of nitrogen removal

    SciTech Connect

    Sincero, A.P.

    1984-11-01

    There has been a great deal of controversy over the issue of nitrogen control from sewage treatment plants discharges to alleviate excessive algae growths in receiving bodies of water. Some of the controversy seems to have risen from a thorough misunderstanding of the microbiology involved in the utilization of nitrogen by microbes. In a haste to control eutrophication, some regulators have required the removal of nitrogen from the effluent of sewage treatment plants; e.g., the Patuxent Nitrogen Removal Policy of the State of Maryland.

  19. Combating Corruption: How the Rule of Law Can Defeat a Culture of Impunity in Afghanistan

    DTIC Science & Technology

    2011-12-01

    Afghanistan,” Report to Congress, November 2010. 2 Michael Hastings, The Operators (Blue Rider Press: New York, New York, 2012) 176. 3 Nathan Hodge and...Kalashnikov, and the Laptop: The Neo-Taliban Insurgency in Afghanistan. Columbia University Press: New York, 2008. Grono, Nick . “Rule of Law and the...Rage at Young Lover.” The New York Times, July 30, 2011: http://www.nytimes.com/2011/07/31/world/asia/31herat.thml_r=1&em=&pagewanted=al Hodge

  20. American surgical biographies.

    PubMed

    Rutkow, I M

    1987-12-01

    Finding adequate biographical data on a given surgeon can cause great difficulty because of the lack of a single source containing biographies of these people. This article provides short biographies of 15 American surgeons of the 18th, 19th, and early 20th centuries: Henry Jacob Bigelow, Joseph Decatur Bryant, Gurdon Buck, John Murray Carnochan, John Syng Dorsey, George Michael Edebohls, Christian Fenger, George Ryerson Fowler, Arpad Geza Charles Gerster, William Gibson, Frank Hastings Hamilton, William Tod Helmuth, Andrew Jackson Howe, Joseph Pancoast, and John Allan Wyeth.

  1. Astrovirus Diagnostics

    PubMed Central

    Pérot, Philippe; Lecuit, Marc; Eloit, Marc

    2017-01-01

    Various methods exist to detect an astrovirus infection. Current methods include electron microscopy (EM), cell culture, immunoassays, polymerase chain reaction (PCR) and various other molecular approaches that can be applied in the context of diagnostic or in surveillance studies. With the advent of metagenomics, novel human astrovirus (HAstV) strains have been found in immunocompromised individuals in association with central nervous system (CNS) infections. This work reviews the past and current methods for astrovirus detection and their uses in both research laboratories and for medical diagnostic purposes. PMID:28085120

  2. Diagnostic neuroradiology for the interventional neuroradiologist

    PubMed Central

    Pereira, Vitor Mendes; Vargas, Maria Isabel; Marcos, Ana; Bijlenga, Philippe; Narata, Ana Paula; Haller, Sven; Lövblad, Karl-Olof

    2013-01-01

    In order to further improve the impact of the continuously evolving neurointerventional techniques, the interventional neuroradiologist needs to have at his disposal more powerful techniques to image the central nervous system. With the recent development of diagnostics techniques that are computed tomography and magnetic resonance based we are now able to assess not just morphology, but also physiology, physiopathology and function. This review discusses the place of diagnostic techniques in the evaluation that the interventional neuroradiologist hast to make when confronted with patients. We provide an overview of current techniques for the brain and spine. PMID:24349643

  3. Waterborne Commerce of the United States, Calendar Year 1986. Part 5. Waterways and Harbors, National Summaries

    DTIC Science & Technology

    1988-05-31

    10,676,900 3,734,295 .......... 215 PUEL WOOD, CHARCOAL . HASTES... al3.30 70.740 33,315 151.193 10.711 3 141039...INLAND $ NANO TOTAL, TRAFFIC TOTAL IMPORTS IENPORTS RECEIPTS ISHIPRENT SHORT TONS 09 1..........0........ ...... . .... 45, 54,9~4,1,9 ,7,0 1146615356...401,945 2412 RAFTED LOGS .......... 14.111,235 2413 FUEL 40OD. CHARCOAL , OWES -- 2.761 190,439 13,202 99.? 351,93 2414 TIMOER, POSTS, POLES, PILING

  4. Outage managment and health physics issue, 2008

    SciTech Connect

    Agnihotri, Newal

    2008-05-15

    The focus of the May-June issue is on outage management and health physics. Major articles include: Outage optimization initiatives, by George B. Beam, AREVA NP, Inc.; New plant based on excellent track records, by Jim Scarola, Progress Energy; Meeting customer needs and providing environmental benefits, by Peter S. Hastings, Duke Energy; Plants with 3-D design, by Jack A. Bailey, Tennessee Valley Authority; and Highest quality with exceptional planning, by Jason A. Walls, Duke Energy. Industry innovation articles include: Integrated exposure reduction plan, by Ed Wolfe, Exelon; Performance-based radiation worker training, by Joe Giuffre and Timothy Vriezerma, American Electric Power.

  5. Detection of a Ferromagnetic Microwire

    DTIC Science & Technology

    2012-09-01

    circular field components, defined as follows: 3 p p s , p p p p p p 0 , 0 , , 0p p p p p ss s , s s s s s s 0 , cos , sin , 0 , 0s s s s s...the DC anisotropy field Ha that fixes the direction of Mst in the material, the depolarization field (5) due to the body’s shape, and the external...time-dependent applied field. Note that in the absence of an ac magnetic field, there is no depolarization field, and so 0M Hast   under DC

  6. Ten Years Post Desert Storm: Has Assault Support Learned the Lessons of Task Force X-Ray?

    DTIC Science & Technology

    2001-04-01

    Blubaugh -2 Capt Schlieker/ Capt Larson -3 Capt Hastings/ 1Lt Milne -4 Capt Moss/ Capt McGee LtCol Doucette/Capt Chartier PAX: LtCol Maloney Maj Schwartz...1Lt Zube -4 Capt Rogers / Capt Walden -1 LtCol Pettine/ -2 Capt Ingram/ -3 Capt Quagge/ -4 Capt Hays/ -1 Capt Erickson/ Capt Jaeger -2 Capt McCormick/Maj...Canty, Jeremiah D., Lieutenant Colonel, USMC, Fifth Flight UH-1N Aircraft Commander HMLA-367, interview by author, 01 May 2001. Chartier , Kirk, Captain

  7. Patience.

    PubMed

    Akhtar, Salman

    2015-02-01

    Patience is a multifaceted phenomenon consisting of acceptance of inner and outer reality, absence of resentment, retention of hope, and capacity to wait for better times without restlessness and haste. It originates in the childhood advance from pleasure principle to reality principle, though the attainment of secure attachment, object constancy, and frustration tolerance also contribute to it. Psychopathology involving patience generally manifests as endless waiting or chronic hurrying. Both the normative and morbid trajectories of patience have implications for psychoanalytic technique, which are illustrated here with the help of clinical vignettes.

  8. A sampling strategy for high-dimensional spaces applied to free-form gravitational lensing

    NASA Astrophysics Data System (ADS)

    Lubini, Mario; Coles, Jonathan

    2012-10-01

    We present a novel proposal strategy for the Metropolis-Hastings algorithm designed to efficiently sample general convex polytopes in 100 or more dimensions. This improves upon previous sampling strategies used for free-form reconstruction of gravitational lenses, but is general enough to be applied to other fields. We have written a parallel implementation within the lens modelling framework GLASS. Testing shows that we are able to produce uniform uncorrelated random samples which are necessary for exploring the degeneracies inherent in lens reconstruction.

  9. Astrovirus Pathogenesis

    PubMed Central

    Johnson, Cydney; Hargest, Virginia; Cortez, Valerie; Meliopoulos, Victoria A.; Schultz-Cherry, Stacey

    2017-01-01

    Astroviruses are a major cause of diarrhea in the young, elderly, and the immunocompromised. Since the discovery of human astrovirus type 1 (HAstV-1) in 1975, the family Astroviridae has expanded to include two more human clades and numerous mammalian and avian-specific genotypes. Despite this, there is still little known about pathogenesis. The following review highlights the current knowledge of astrovirus pathogenesis, and outlines the critical steps needed to further astrovirus research, including the development of animal models of cell culture systems. PMID:28117758

  10. [Discharge of very preterm infants from neonatology: check list].

    PubMed

    Arnaud, F

    2004-02-01

    Key elements of the check list for neonatal discharge include: discharge discussion with parents, relation with maternal and child welfare assistants and family practitioner, scheduling of follow-up visits, request for insurance coverage, parental presence allowance, special education allowance, debriefing with nurses and nurses providers, clinical and biological appraisal, discharge prescription. For a former extremely premature baby, going home - often after a long hospitalization and a variety of pathologic problems - must be prepared and should not be decided in haste, not only for the baby and his/her parents, but also. for the neonatal staff!

  11. Foreign Bodies in the Aerodigestive Tract

    PubMed Central

    Lawson, Victor G.; Middleton, William G.

    1986-01-01

    Foreign bodies in the aerodigestive tract are common. They may cause minimal disturbance of function, severe morbidity or even sudden death. They enter the aerodigestive tract because of haste during eating, disturbances in physical function, impairments due to extreme youth or age, or contamination of food with foreign bodies. Common symptoms are pain, dysphagia, odynophagia, cough, airway distress, hemoptysis and hematemesis. Signs include point tenderness, respiratory distress and surgical emphysema. Clinical, radiological and endoscopic investigations are described, as are principles of crisis and elective management. ImagesFig. 1Fig. 2Fig. 3Fig. 4Fig. 5Fig. 6Fig. 7Fig. 8Fig. 9 PMID:21267132

  12. MIL-STD-1760 Application Guidelines

    DTIC Science & Technology

    1991-09-01

    AD-A255 714 ASD-TR-91-5009 MIL-STD-1760 APPLICATION GUIDELINES Computing Devices Company Hastings, East Sussex, England Control Data Corporation DTIC...other data, is not to be regarded by implication, or otherwise in any manner construed, as licensing the holder, or any other person or corporation ...S) 182-80-18 ASD-TR-91-5009 6a NAME OF PERFORMINC ORGANIZATION 6b. OFFICE SYMBOL 7a. NAME OF MONITORING ORGANIZATION Contrcl Di~ta Corporation (if

  13. Markov Chain Monte Carlo Used in Parameter Inference of Magnetic Resonance Spectra

    DOE PAGES

    Hock, Kiel; Earle, Keith

    2016-02-06

    In this paper, we use Boltzmann statistics and the maximum likelihood distribution derived from Bayes’ Theorem to infer parameter values for a Pake Doublet Spectrum, a lineshape of historical significance and contemporary relevance for determining distances between interacting magnetic dipoles. A Metropolis Hastings Markov Chain Monte Carlo algorithm is implemented and designed to find the optimum parameter set and to estimate parameter uncertainties. In conclusion, the posterior distribution allows us to define a metric on parameter space that induces a geometry with negative curvature that affects the parameter uncertainty estimates, particularly for spectra with low signal to noise.

  14. Markov chain Monte Carlo methods: an introductory example

    NASA Astrophysics Data System (ADS)

    Klauenberg, Katy; Elster, Clemens

    2016-02-01

    When the Guide to the Expression of Uncertainty in Measurement (GUM) and methods from its supplements are not applicable, the Bayesian approach may be a valid and welcome alternative. Evaluating the posterior distribution, estimates or uncertainties involved in Bayesian inferences often requires numerical methods to avoid high-dimensional integrations. Markov chain Monte Carlo (MCMC) sampling is such a method—powerful, flexible and widely applied. Here, a concise introduction is given, illustrated by a simple, typical example from metrology. The Metropolis-Hastings algorithm is the most basic and yet flexible MCMC method. Its underlying concepts are explained and the algorithm is given step by step. The few lines of software code required for its implementation invite interested readers to get started. Diagnostics to evaluate the performance and common algorithmic choices are illustrated to calibrate the Metropolis-Hastings algorithm for efficiency. Routine application of MCMC algorithms may be hindered currently by the difficulty to assess the convergence of MCMC output and thus to assure the validity of results. An example points to the importance of convergence and initiates discussion about advantages as well as areas of research. Available software tools are mentioned throughout.

  15. Effect of High Temperature Storage in Vacuum, Air, and Humid Conditions on Degradation of Gold/Aluminum Wire Bonds in PEMs

    NASA Technical Reports Server (NTRS)

    Teverovsky, Alexander

    2006-01-01

    Microcircuits encapsulated in three plastic package styles were stored in different environments at temperatures varying from 130 C to 225 C for up to 4,000 hours in some cases. To assess the effect of oxygen, the parts were aged at high temperatures in air and in vacuum chambers. The effect of humidity was evaluated during long-term highly accelerated temperature and humidity stress testing (HAST) at temperatures of 130 C and 150 C. High temperature storage testing of decapsulated microcircuits in air, vacuum, and HAST chambers was carried out to evaluate the role of molding compounds in the environmentally-induced degradation and failure of wire bonds (WB). This paper reports on accelerating factors of environment and molding compound on WB failures. It has been shown that all environments, including oxygen, moisture, and the presence of molding compounds reduce time-to-failures compared to unencapsulated devices in vacuum conditions. The mechanism of the environmental effect on KB degradation is discussed.

  16. Dynamic collision-induced dissociation of peptides in a quadrupole ion trap mass spectrometer.

    PubMed

    Collin, Olivier L; Beier, Matthias; Jackson, Glen P

    2007-07-15

    The fragmentation of natural peptides using dynamic collision-induced dissociation (DCID), a novel fragmentation method for quadrupole ion traps, is demonstrated. Using leucine enkephalin as a diagnostic molecule, the fragmentation efficiencies and energetics of DCID are compared with other methods of collisional activation in ion traps such as conventional on-resonance excitation and high-amplitude short-time excitation (HASTE). A typical fragmentation efficiency of approximately 20% is achieved for DCID, which is significantly lower than conventional CID (maximum near 80%). Tandem mass spectra of two other peptides, substance P and oxidized insulin alpha-chain, demonstrate that product ion spectra for DCID are comparable to conventional or HASTE CID. Because DCID achieves fragmentation during the standard mass acquisition scan, no extra time is necessary for on-resonance excitation or product ion collection, so analysis times are reduced by a minimum of 10-15% depending on the scanning conditions. DCID therefore offers more tandem mass spectra per second than conventional methods of collisional activation, which could be highly advantageous for bottom-up proteomics separations.

  17. Ultra-thin atomic-layer deposited alumina incorporating silica sol makes ultra-durable antireflection coatings

    NASA Astrophysics Data System (ADS)

    Li, Jia; Lan, Pinjun; Xu, Hua; Zhang, Xianpeng; Yang, Ye; Tan, Ruiqin; Jylhä, Olli; Lu, Yuehui

    2012-11-01

    We propose a strategy to make soda-lime glass maintain both high transparency and long-term durability in stringent high temperature and humid environments. Experiments reveal that the double-layered coatings with 110-nm-thick SiO2 and ultra-thin 25-nm- or 50-nm-thick Al2O3 layers, prepared by sol-gel dip coating and atomic layer deposition (ALD), respectively, exhibit the improvement of 5.88-6.32% in Tave (the average transmittance from the wavelength of 400-700 nm), as compared with that of the bare glass. On the other hand, the highly accelerated temperature and humidity stress test (HAST) confirms that both samples can sustain the 180 h test without any proven transmittance degradation, while the normalized Tave of the bare glass drastically drops to 43.1% of the initial value after the 108 h HAST. It implies that the ultra-thin Al2O3 films prepared by ALD, followed by dip-coated low-index layers such as SiO2 or nanostructured layer, can achieve both higher average transmittance and better durability, which would be of significance for the applications of ALD and dip coating techniques in the fields of consumer electronics, architecture with glass facades, and photovoltaics.

  18. Fitting complex population models by combining particle filters with Markov chain Monte Carlo.

    PubMed

    Knape, Jonas; de Valpine, Perry

    2012-02-01

    We show how a recent framework combining Markov chain Monte Carlo (MCMC) with particle filters (PFMCMC) may be used to estimate population state-space models. With the purpose of utilizing the strengths of each method, PFMCMC explores hidden states by particle filters, while process and observation parameters are estimated using an MCMC algorithm. PFMCMC is exemplified by analyzing time series data on a red kangaroo (Macropus rufus) population in New South Wales, Australia, using MCMC over model parameters based on an adaptive Metropolis-Hastings algorithm. We fit three population models to these data; a density-dependent logistic diffusion model with environmental variance, an unregulated stochastic exponential growth model, and a random-walk model. Bayes factors and posterior model probabilities show that there is little support for density dependence and that the random-walk model is the most parsimonious model. The particle filter Metropolis-Hastings algorithm is a brute-force method that may be used to fit a range of complex population models. Implementation is straightforward and less involved than standard MCMC for many models, and marginal densities for model selection can be obtained with little additional effort. The cost is mainly computational, resulting in long running times that may be improved by parallelizing the algorithm.

  19. Searching for efficient Markov chain Monte Carlo proposal kernels.

    PubMed

    Yang, Ziheng; Rodríguez, Carlos E

    2013-11-26

    Markov chain Monte Carlo (MCMC) or the Metropolis-Hastings algorithm is a simulation algorithm that has made modern Bayesian statistical inference possible. Nevertheless, the efficiency of different Metropolis-Hastings proposal kernels has rarely been studied except for the Gaussian proposal. Here we propose a unique class of Bactrian kernels, which avoid proposing values that are very close to the current value, and compare their efficiency with a number of proposals for simulating different target distributions, with efficiency measured by the asymptotic variance of a parameter estimate. The uniform kernel is found to be more efficient than the Gaussian kernel, whereas the Bactrian kernel is even better. When optimal scales are used for both, the Bactrian kernel is at least 50% more efficient than the Gaussian. Implementation in a Bayesian program for molecular clock dating confirms the general applicability of our results to generic MCMC algorithms. Our results refute a previous claim that all proposals had nearly identical performance and will prompt further research into efficient MCMC proposals.

  20. Inscribed matter as an energy-efficient means of communication with an extraterrestrial civilization.

    PubMed

    Rose, Christopher; Wright, Gregory

    2004-09-02

    It is well known that electromagnetic radiation-radio waves-can in principle be used to communicate over interstellar distances. By contrast, sending physical artefacts has seemed extravagantly wasteful of energy, and imagining human travel between the stars even more so. The key consideration in earlier work, however, was the perceived need for haste. If extraterrestrial civilizations existed within a few tens of light years, radio could be used for two-way communication on timescales comparable to human lifetimes (or at least the longevities of human institutions). Here we show that if haste is unimportant, sending messages inscribed on some material can be strikingly more energy efficient than communicating by electromagnetic waves. Because messages require protection from cosmic radiation and small messages could be difficult to find among the material clutter near a recipient, 'inscribed matter' is most effective for long archival messages (as opposed to potentially short "we exist" announcements). The results suggest that our initial contact with extraterrestrial civilizations may be more likely to occur through physical artefacts-essentially messages in a bottle-than via electromagnetic communication.

  1. Identification of a vacuolar proton channel that triggers the bioluminescent flash in dinoflagellates.

    PubMed

    Rodriguez, Juan D; Haq, Saddef; Bachvaroff, Tsvetan; Nowak, Kristine F; Nowak, Scott J; Morgan, Deri; Cherny, Vladimir V; Sapp, Maredith M; Bernstein, Steven; Bolt, Andrew; DeCoursey, Thomas E; Place, Allen R; Smith, Susan M E

    2017-01-01

    In 1972, J. Woodland Hastings and colleagues predicted the existence of a proton selective channel (HV1) that opens in response to depolarizing voltage across the vacuole membrane of bioluminescent dinoflagellates and conducts protons into specialized luminescence compartments (scintillons), thereby causing a pH drop that triggers light emission. HV1 channels were subsequently identified and demonstrated to have important functions in a multitude of eukaryotic cells. Here we report a predicted protein from Lingulodinium polyedrum that displays hallmark properties of bona fide HV1, including time-dependent opening with depolarization, perfect proton selectivity, and characteristic ΔpH dependent gating. Western blotting and fluorescence confocal microscopy of isolated L. polyedrum scintillons immunostained with antibody to LpHV1 confirm LpHV1's predicted organellar location. Proteomics analysis demonstrates that isolated scintillon preparations contain peptides that map to LpHV1. Finally, Zn2+ inhibits both LpHV1 proton current and the acid-induced flash in isolated scintillons. These results implicate LpHV1 as the voltage gated proton channel that triggers bioluminescence in L. polyedrum, confirming Hastings' hypothesis. The same channel likely mediates the action potential that communicates the signal along the tonoplast to the scintillon.

  2. Hi'iaka: Haumea's Rapidly Spinning Moon

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2017-02-01

    An image from the Keck telescope of the dwarf planet Haumea (center) and its two moons, Hiiaka (above) and Namaka (below). [Caltech/Keck/Mike Brown]Recent observations of Hiiaka, the largest satellite of the dwarf planet Haumea, reveal that the moon is spinning much more rapidly than expected. What could this tell us about how Haumea and its moons formed?A Distant DwarfThe dwarf planet Haumea orbits beyond Neptune and has a mass of roughly 1/3 that of Pluto. Like Pluto, Haumea also has companions: two satellites of roughly 0.5% and 0.05% of Haumeas mass, orbiting at rather large distances of 36 and 70 Haumea radii (roughly 26,000 and 50,000 km).In a recently published study, a team led by Danielle Hastings (UC Los Angeles and Florida Institute of Technology) explored Hubble and Magellan observations of Hiiaka Haumeas larger, outer satellite to determine the rate at which it rotates on its axis.Hiiakas light curve, phase-folded at its most likely rotation period of 9.8 hours. The double peak is due to the fact that Hiiaka is likely not a spherical body, so it shows two maxima in brightness in each full rotation. [Hastings et al. 2016]Rapid RotationNominally, wed expect Hiiaka to be rotating synchronously its rotation period should be the same as its orbital period of 49.5 days. We expect this because the amount of time needed for tidal forces to despin Hiiaka to synchronous rotation should be much shorter than the time needed for these forces to produce Hiiakas observed low eccentricity and large semimajor axis.Therefore it was quite the surprise when Hastings and collaborators analyzed Hiiakas light curve and found that the moon revolves on its axis once every 9.8 hours! Thats roughly 120 times faster than the expected synchronous rate.Formation TheoriesWhat does this discovery reveal about Hiiakas formation? Hastings and collaborators propose three possible scenarios. They then use analytic calculations and numerical simulations to try to constrain them based on

  3. Frontoparietal white matter integrity predicts haptic performance in chronic stroke.

    PubMed

    Borstad, Alexandra L; Choi, Seongjin; Schmalbrock, Petra; Nichols-Larsen, Deborah S

    2016-01-01

    Frontoparietal white matter supports information transfer between brain areas involved in complex haptic tasks such as somatosensory discrimination. The purpose of this study was to gain an understanding of the relationship between microstructural integrity of frontoparietal network white matter and haptic performance in persons with chronic stroke and to compare frontoparietal network integrity in participants with stroke and age matched control participants. Nineteen individuals with stroke and 16 controls participated. Haptic performance was quantified using the Hand Active Sensation Test (HASTe), an 18-item match-to-sample test of weight and texture discrimination. Three tesla MRI was used to obtain diffusion-weighted and high-resolution anatomical images of the whole brain. Probabilistic tractography was used to define 10 frontoparietal tracts total; Four intrahemispheric tracts measured bilaterally 1) thalamus to primary somatosensory cortex (T-S1), 2) thalamus to primary motor cortex (T-M1), 3) primary to secondary somatosensory cortex (S1 to SII) and 4) primary somatosensory cortex to middle frontal gyrus (S1 to MFG) and, 2 interhemispheric tracts; S1-S1 and precuneus interhemispheric. A control tract outside the network, the cuneus interhemispheric tract, was also examined. The diffusion metrics fractional anisotropy (FA), mean diffusivity (MD), axial (AD) and radial diffusivity (RD) were quantified for each tract. Diminished FA and elevated MD values are associated with poorer white matter integrity in chronic stroke. Nine of 10 tracts quantified in the frontoparietal network had diminished structural integrity poststroke compared to the controls. The precuneus interhemispheric tract was not significantly different between groups. Principle component analysis across all frontoparietal white matter tract MD values indicated a single factor explained 47% and 57% of the variance in tract mean diffusivity in stroke and control groups respectively. Age

  4. Improving fitness of elite handball players: small-sided games vs. high-intensity intermittent training.

    PubMed

    Iacono, Antonio Dello; Eliakim, Alon; Meckel, Yoav

    2015-03-01

    The present study was designed to compare the effects of high-intensity intermittent training (HIIT) and small-sided games (SSGs) training on fitness variables of elite handball players. Eighteen highly trained players (mean age ± SD: 25.6 ± 0.5 years) were assigned to either HIIT or SSGs group training protocols twice per week for 8 weeks. The HIIT consisted of 12-24 × 15 seconds of high-intensity runs interspersed by 15 seconds of recovery. The SSGs training consisted of 3 against 3 small-sided handball games. Both training methods were matched for exercise duration and recovery at each training session. Before and after 8-week training, the following fitness variables were assessed-speed: 10- and 20-m sprint time, agility: handball agility specific test (HAST), upper arm strength: 1 repetition maximum (1RM) bench press test, lower limb power: counter-movement jump tests with (CMJarm) and without (CMJ) arm movement, and aerobic fitness (yo-yo intermittent recovery test level 1 [YYIRTL1]). Significant improvement was found in the YYIRTL1 (23.3 and 26.3%, respectively), 10-m sprint (2.3 and 4.1%, respectively) and 20-m sprint (2.1 and 4%, respectively), HAST (1.1 and 2.2%, respectively), 1RM bench press (6.8 and 12.3%, respectively), CMJ (7.4 and 10.8%, respectively), and CMJarm (6.4 and 8.9%, respectively) following training in both groups (p ≤ 0.05 for all). There was a significantly greater improvement in 10- and 20-m sprint, HAST, 1RM, CMJ, and CMJarm following the SSGs training compared with the HIIT (p ≤ 0.05 for all). These results indicated that both HIIT and SSGs are effective training methods for fitness development among elite adult handball players. However, SSGs training may be considered as the preferred training regimen for improving handball-specific fitness variables during the in-season period.

  5. Mid-Eocene alluvial-lacustrine succession at Gebel El-Goza El-Hamra (Shabrawet area, NE Eastern Desert, Egypt): Facies analysis, sequence stratigraphy and paleoclimatic implications

    NASA Astrophysics Data System (ADS)

    Wanas, H. A.; Sallam, E.; Zobaa, M. K.; Li, X.

    2015-11-01

    This study aims to provide the depositional facies, sequence stratigraphic and paleoclimatic characteristics of the Mid-Eocene (Bartonian) continental succession exposed at Gebel El-Goza El-Hamra (Shabrawet Area, NE Eastern Desert, Egypt). The studied succession consists of siliciclastic rocks followed upward by carbonate rocks. Detailed field observation and petrographic investigation indicate accumulation in floodplain-dominated alluvial and shallow lacustrine systems. The floodplain-dominated alluvial facies (45 m thick) is composed mainly of carbonate nodules-bearing, mottled mudrock with subordinate sandstone and conglomerate beds. The conglomerate and pebbly sandstone bodies interpreted as ephemeral braided channel deposits. The massive, laminated, planner cross-bedded, fine- to medium-grained sandstone bodies interlayered within mudstone reflect sheet flood deposits. The mudrocks associated with paleosols represent distal floodplain deposits. The shallow lacustrine facies (15 m thick) is made up of an alternation of marlstone, micritic limestone, dolostone and mudrock beds with charophytes and small gastropods. Both the alluvial and lacustrine facies show evidence of macro-and micro-pedogenic features. Pollen assemblages, stable δ18O and δ13C isotopes, and paleopedogenic features reflect prevalence of arid to semi-arid climatic conditions during the Bartonian. The sequence stratigraphic framework shows an overall fining-upward depositional sequence, consisting of Low- and High-accommodation Systems Tracts (LAST, HAST), and is bounded by two sequence boundaries (SB-1, SB-2). Conglomerate and pebbly sandstone deposits (braided channel and sheet flood deposits) of the lower part of the alluvial facies reflect a LAST. Mudrock and silty claystone facies (distal floodplain deposits) of the upper part of alluvial facies and its overlying lacustrine facies correspond to a HAST. The LAST, HAST and SB were formed during different accommodation-to-sediment supply (A

  6. DNA Microarray for Detection of Gastrointestinal Viruses

    PubMed Central

    Martínez, Miguel A.; Soto-del Río, María de los Dolores; Gutiérrez, Rosa María; Chiu, Charles Y.; Greninger, Alexander L.; Contreras, Juan Francisco; López, Susana; Arias, Carlos F.

    2014-01-01

    Gastroenteritis is a clinical illness of humans and other animals that is characterized by vomiting and diarrhea and caused by a variety of pathogens, including viruses. An increasing number of viral species have been associated with gastroenteritis or have been found in stool samples as new molecular tools have been developed. In this work, a DNA microarray capable in theory of parallel detection of more than 100 viral species was developed and tested. Initial validation was done with 10 different virus species, and an additional 5 species were validated using clinical samples. Detection limits of 1 × 103 virus particles of Human adenovirus C (HAdV), Human astrovirus (HAstV), and group A Rotavirus (RV-A) were established. Furthermore, when exogenous RNA was added, the limit for RV-A detection decreased by one log. In a small group of clinical samples from children with gastroenteritis (n = 76), the microarray detected at least one viral species in 92% of the samples. Single infection was identified in 63 samples (83%), and coinfection with more than one virus was identified in 7 samples (9%). The most abundant virus species were RV-A (58%), followed by Anellovirus (15.8%), HAstV (6.6%), HAdV (5.3%), Norwalk virus (6.6%), Human enterovirus (HEV) (9.2%), Human parechovirus (1.3%), Sapporo virus (1.3%), and Human bocavirus (1.3%). To further test the specificity and sensitivity of the microarray, the results were verified by reverse transcription-PCR (RT-PCR) detection of 5 gastrointestinal viruses. The RT-PCR assay detected a virus in 59 samples (78%). The microarray showed good performance for detection of RV-A, HAstV, and calicivirus, while the sensitivity for HAdV and HEV was low. Furthermore, some discrepancies in detection of mixed infections were observed and were addressed by reverse transcription-quantitative PCR (RT-qPCR) of the viruses involved. It was observed that differences in the amount of genetic material favored the detection of the most abundant

  7. Quantitative analysis of the breath-holding half-Fourier acquisition single-shot turbo spin-echo technique in abdominal MRI

    NASA Astrophysics Data System (ADS)

    Dong, Kyung-Rae; Goo, Eun-Hoe; Lee, Jae-Seung; Chung, Woon-Kwan

    2013-01-01

    A consecutive series of 50 patients (28 males and 22 females) who underwent hepatic magnetic resonance imaging (MRI) from August to December 2011 were enrolled in this study. The appropriate parameters for abdominal MRI scans were determined by comparing the images (TE = 90 and 128 msec) produced using the half-Fourier acquisition single-shot turbo spin-echo (HASTE) technique at different signal acquisition times. The patients consisted of 15 normal patients, 25 patients with a hepatoma and 10 patients with a hemangioma. The TE in a single patient was set to either 90 msec or 128 msec. This was followed by measurements using the four normal rendering methods of the biliary tract system and the background signal intensity using the maximal signal intensity techniques in the liver, spleen, pancreas, gallbladder, fat, muscles and hemangioma. The signal-to-noise and the contrast-to-noise ratios were obtained. The image quality was assessed subjectively, and the results were compared. The signal-to-noise and the contrast-to-noise ratios were significantly higher at TE = 128 msec than at TE = 90 when diseases of the liver, spleen, pancreas, gallbladder, and fat and muscles, hepatocellular carcinomas and hemangiomas, and rendering the hepatobiliary tract system based on the maximum signal intensity technique were involved (p < 0.05). In addition, the presence of artifacts, the image clarity and the overall image quality were excellent at TE = 128 msec (p < 0.05). In abdominal MRI, the breath-hold half-Fourier acquisition single-shot turbo spin-echo (HASTE) was found to be effective in illustrating the abdominal organs for TE = 128 msec. Overall, the image quality at TE = 128 msec was better than that at TE = 90 msec due to the improved signal-to-noise (SNR) and contrast-to-noise (CNR) ratios. Overall, the HASTE technique for abdominal MRI based on a high-magnetic field (3.0 T) at a TE of 128 msec can provide useful data.

  8. DNA microarray for detection of gastrointestinal viruses.

    PubMed

    Martínez, Miguel A; Soto-Del Río, María de Los Dolores; Gutiérrez, Rosa María; Chiu, Charles Y; Greninger, Alexander L; Contreras, Juan Francisco; López, Susana; Arias, Carlos F; Isa, Pavel

    2015-01-01

    Gastroenteritis is a clinical illness of humans and other animals that is characterized by vomiting and diarrhea and caused by a variety of pathogens, including viruses. An increasing number of viral species have been associated with gastroenteritis or have been found in stool samples as new molecular tools have been developed. In this work, a DNA microarray capable in theory of parallel detection of more than 100 viral species was developed and tested. Initial validation was done with 10 different virus species, and an additional 5 species were validated using clinical samples. Detection limits of 1 × 10(3) virus particles of Human adenovirus C (HAdV), Human astrovirus (HAstV), and group A Rotavirus (RV-A) were established. Furthermore, when exogenous RNA was added, the limit for RV-A detection decreased by one log. In a small group of clinical samples from children with gastroenteritis (n = 76), the microarray detected at least one viral species in 92% of the samples. Single infection was identified in 63 samples (83%), and coinfection with more than one virus was identified in 7 samples (9%). The most abundant virus species were RV-A (58%), followed by Anellovirus (15.8%), HAstV (6.6%), HAdV (5.3%), Norwalk virus (6.6%), Human enterovirus (HEV) (9.2%), Human parechovirus (1.3%), Sapporo virus (1.3%), and Human bocavirus (1.3%). To further test the specificity and sensitivity of the microarray, the results were verified by reverse transcription-PCR (RT-PCR) detection of 5 gastrointestinal viruses. The RT-PCR assay detected a virus in 59 samples (78%). The microarray showed good performance for detection of RV-A, HAstV, and calicivirus, while the sensitivity for HAdV and HEV was low. Furthermore, some discrepancies in detection of mixed infections were observed and were addressed by reverse transcription-quantitative PCR (RT-qPCR) of the viruses involved. It was observed that differences in the amount of genetic material favored the detection of the most abundant

  9. 31. WEST TO PARTS AND TOOLS LOCATED DIRECTLY OPPOSITE FROM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    31. WEST TO PARTS AND TOOLS LOCATED DIRECTLY OPPOSITE FROM THE BLACKSMITH SHOP AREA IN THE NORTHEAST QUADRANT OF THE FACTORY. ON THE FLOOR AT THE LEFT SIDE IS A MANUAL PIPE THREADER FOR LARGE-DIAMETER PIPE (AS DROP PIPE IN WELLS FOR WATER SYSTEMS). BENEATH THE BENCH ARE UNMACHINED NEW OLD STOCK MAIN CASTINGS FOR ELI WINDMILLS, TOGETHER WITH A USED MAIN SHAFT/WHEEL HUB/CRANK PLATE ASSEMBLY WITH 1920S-1930S OIL RESERVOIR FROM ELI WINDMILL. THE CIRCULAR CASTING WITH CRESCENT-SHAPED PATTERNS IS A PORTION OF THE CAM MECHANISM FROM A 'WESTERN GEARED GEARLESS' WINDMILL MADE BY THE WESTERN LAND ROLLER CO., HASTINGS, NEB. TO THE RIGHT ON THE BENCH IS A GEARED TIRE BENDER USED TO GIVE CURVATURE TO WHEEL RIMS OF ELI WINDMILLS. IN THE BACKGROUND ARE ... - Kregel Windmill Company Factory, 1416 Central Avenue, Nebraska City, Otoe County, NE

  10. Where Shall We Go?

    PubMed

    Kaebnick, Gregory E

    2016-09-01

    This issue of the Hastings Center Report coincides with the annual conference of the American Society for Bioethics and Humanities, whose theme this year is "Where do we stand?" The issue addresses that theme with the article by Debra Mathews and colleagues and the set of brief response essays that follow it. Mathews et al., drawing on work carried out by the Association of Bioethics Program Directors, pose questions about how to understand and evaluate the worth of bioethics research. Those questions require them to think very broadly about what bioethics is, in the first place, and how it is related to medicine, health policy, science, and society generally. In short, they are thinking at the highest level about the question, where do we stand?

  11. Committees

    NASA Astrophysics Data System (ADS)

    Williams, Gwyn P.; Revesz, Peter; Arp, Uwe

    2014-03-01

    Conference Chairs NameOrganization Gwyn Williams Jefferson Lab Peter ReveszCornell High Energy Synchrotron Source Uwe ArpSynchrotron Ultraviolet Radiation Facility Programme Committee NameOrganization Alastair MacDowellAdvanced Light Source Tom ToellnerAdvanced Photon Source Amitava D RoyCenter for Advanced Microstructures and Devices Tom EllisCanadian Light Source Roberta SantarosaLaboratório Nacional de Luz Síncrotron Jerry (Jerome) HastingsLinac Coherent Light Source Steven HulbertNational Synchrotron Light Source Thomas A RabedeauStanford Synchrotron Radiation Lightsource Mark BissenSynchrotron Radiation Center Gwyn WilliamsJefferson Lab Peter ReveszCornell High Energy Synchrotron Source Uwe ArpSynchrotron Ultraviolet Radiation Facility

  12. Bayesian Variable Selection on Model Spaces Constrained by Heredity Conditions.

    PubMed

    Taylor-Rodriguez, Daniel; Womack, Andrew; Bliznyuk, Nikolay

    2016-01-01

    This paper investigates Bayesian variable selection when there is a hierarchical dependence structure on the inclusion of predictors in the model. In particular, we study the type of dependence found in polynomial response surfaces of orders two and higher, whose model spaces are required to satisfy weak or strong heredity conditions. These conditions restrict the inclusion of higher-order terms depending upon the inclusion of lower-order parent terms. We develop classes of priors on the model space, investigate their theoretical and finite sample properties, and provide a Metropolis-Hastings algorithm for searching the space of models. The tools proposed allow fast and thorough exploration of model spaces that account for hierarchical polynomial structure in the predictors and provide control of the inclusion of false positives in high posterior probability models.

  13. Militant morality: civil disobedience and bioethics.

    PubMed

    Cohen, C

    1989-01-01

    Seven essays in this issue of the Hastings Center Report defend civil disobedience as a legitimate form of protest against terrible injustices: legalized abortion (G. Leber); abridgement of women's reproductive rights (S. Davis); government policy toward persons with AIDS (H. Spiers and A. Novick); abuse of the rights of animals (S. Siegel, C. Jackson, and P. Singer). An eighth essay, by B. Nathanson, examines the motivations of Operation Rescue, an organization that uses civil disobedience to protest legalized abortion. Cohen explores the problems that these authors and others encounter in trying to justify deliberately breaking the law in public conscientious protest. He examines three forms of protest -- direct civil disobedience, indirect civil disobedience, and direct action -- and three justifications -- higher-law, utilitarian, and only possible means. Cohen concludes that, in a democracy, objective justification of civil disobedience is very difficult.

  14. Sampling schemes and parameter estimation for nonlinear Bernoulli-Gaussian sparse models

    NASA Astrophysics Data System (ADS)

    Boudineau, Mégane; Carfantan, Hervé; Bourguignon, Sébastien; Bazot, Michael

    2016-06-01

    We address the sparse approximation problem in the case where the data are approximated by the linear combination of a small number of elementary signals, each of these signals depending non-linearly on additional parameters. Sparsity is explicitly expressed through a Bernoulli-Gaussian hierarchical model in a Bayesian framework. Posterior mean estimates are computed using Markov Chain Monte-Carlo algorithms. We generalize the partially marginalized Gibbs sampler proposed in the linear case in [1], and build an hybrid Hastings-within-Gibbs algorithm in order to account for the nonlinear parameters. All model parameters are then estimated in an unsupervised procedure. The resulting method is evaluated on a sparse spectral analysis problem. It is shown to converge more efficiently than the classical joint estimation procedure, with only a slight increase of the computational cost per iteration, consequently reducing the global cost of the estimation procedure.

  15. A Markov-Chain Monte-Carlo Based Method for Flaw Detection in Beams

    SciTech Connect

    Glaser, R E; Lee, C L; Nitao, J J; Hickling, T L; Hanley, W G

    2006-09-28

    A Bayesian inference methodology using a Markov Chain Monte Carlo (MCMC) sampling procedure is presented for estimating the parameters of computational structural models. This methodology combines prior information, measured data, and forward models to produce a posterior distribution for the system parameters of structural models that is most consistent with all available data. The MCMC procedure is based upon a Metropolis-Hastings algorithm that is shown to function effectively with noisy data, incomplete data sets, and mismatched computational nodes/measurement points. A series of numerical test cases based upon a cantilever beam is presented. The results demonstrate that the algorithm is able to estimate model parameters utilizing experimental data for the nodal displacements resulting from specified forces.

  16. [Nutrition habits of students of University of Economics in Wroclaw].

    PubMed

    Kowalska, Anna

    2010-01-01

    The aim of a paper was an assessment of Wroclaw University of Economics students nutritional habits. Purposeful sample group selection was opted in this surrey. The method Ch2 was used to analyses questionnaire data. Obtained results confirm, that most of student don't nourish properly. Irregular breakfast before leaving home is the most frequent incorrectness, as well as irregular second breakfast or resignation from second breakfast at work or on classes breaks. Dinners consumption for large group of polled was irregular too. Lack of proper nutrition habits among young people is the cause of this state. Young people haste and limited finance causing that most of polled. Students consume only one course meal, mostly preparing by themselves. Basic foodstuffs i.e. meat, fishes, poultry, dairy products and fruits and vegetables or more often. Large group of students (especially women) declared eating sweets to often.

  17. Detection of spatially extended sources in high energy astrophysics with special application to lunar occultation

    NASA Astrophysics Data System (ADS)

    Jenke, Peter Alexander

    2009-01-01

    Occultation is a technique that enables image reconstruction and source identification with a non-imaging detector. Such an approach is well suited for a future survey mission in nuclear astrophysics. In particular, the Lunar Occultation Technique (LOT) utilizes the Moon as an occulting object and is the basis of a new gamma-ray survey mission concept, the Lunar OCcultation Observer (LOCO). Techniques utilizing the LOT to detect spatially extended emission, from the Galactic plane or Galactic Center region, have been developed. Given knowledge of detector position in lunar orbit, combined with lunar ephemeris and relevant coordinate transformations, occultation time series can be used to reconstruct skymaps of these extended Galactic emitters. Monte-Carlo Markov Chains (MCMC), incorporating the Metropolis-Hastings algorithm for parametric model testing, form the basis of the technique. Performance of the imaging methodology, and its application to nuclear astrophysics will be presented.

  18. SYSTEMIC TOXIC REACTIONS TO LOCAL ANESTHETICS

    PubMed Central

    Moore, Daniel C.; Green, John

    1956-01-01

    The topical use of anesthetic agents involves an element of risk. Systemic toxic reactions are rare, but they do occur and may result in death. When a reaction occurs from a topical application, it usually progresses rapidly to respiratory and cardiovascular collapse, and thus therapy must be instituted with more haste to avoid deaths. Fatal systemic toxic reactions from topically administered anesthetic drugs are, in effect, usually not due to well informed use of the drug but to misuse owing to less than complete understanding of absorption. Emphasis is placed on the causes, prophylaxis and treatment of severe systemic toxic reactions which follow the topical application of local anesthetic drugs. If systemic toxic reactions resulting from a safe dose of a local anesthetic agent are correctly treated, there will usually follow an uneventful recovery rather than a catastrophe. PMID:13343009

  19. Molecular dynamics simulations of field emission from a planar nanodiode

    NASA Astrophysics Data System (ADS)

    Torfason, Kristinn; Valfells, Agust; Manolescu, Andrei

    2015-03-01

    High resolution molecular dynamics simulations with full Coulomb interactions of electrons are used to investigate field emission in planar nanodiodes. The effects of space-charge and emitter radius are examined and compared to previous results concerning transition from Fowler-Nordheim to Child-Langmuir current [Y. Y. Lau, Y. Liu, and R. K. Parker, Phys. Plasmas 1, 2082 (1994) and Y. Feng and J. P. Verboncoeur, Phys. Plasmas 13, 073105 (2006)]. The Fowler-Nordheim law is used to determine the current density injected into the system and the Metropolis-Hastings algorithm to find a favourable point of emission on the emitter surface. A simple fluid like model is also developed and its results are in qualitative agreement with the simulations.

  20. Understanding the agreements and controversies surrounding childhood psychopharmacology

    PubMed Central

    Parens, Erik; Johnston, Josephine

    2008-01-01

    The number of children in the US taking prescription drugs for emotional and behavioral disturbances is growing dramatically. This growth in the use of psychotropic drugs in pediatric populations has given rise to multiple controversies, ranging from concerns over off-label use and long-term safety to debates about the societal value and cultural meaning of pharmacological treatment of childhood behavioral and emotional disorders. This commentary summarizes the authors' eight main findings from the first of five workshops that seek to understand and produce descriptions of these controversies. The workshop series is convened by The Hastings Center, a bioethics research institute located in Garrison, New York, U.S.A. PMID:18261228

  1. Irreversible Markov chain Monte Carlo algorithm for self-avoiding walk

    NASA Astrophysics Data System (ADS)

    Hu, Hao; Chen, Xiaosong; Deng, Youjin

    2017-02-01

    We formulate an irreversible Markov chain Monte Carlo algorithm for the self-avoiding walk (SAW), which violates the detailed balance condition and satisfies the balance condition. Its performance improves significantly compared to that of the Berretti-Sokal algorithm, which is a variant of the Metropolis-Hastings method. The gained efficiency increases with spatial dimension (D), from approximately 10 times in 2D to approximately 40 times in 5D. We simulate the SAW on a 5D hypercubic lattice with periodic boundary conditions, for a linear system with a size up to L = 128, and confirm that as for the 5D Ising model, the finite-size scaling of the SAW is governed by renormalized exponents, v* = 2/ d and γ/ v* = d/2. The critical point is determined, which is approximately 8 times more precise than the best available estimate.

  2. A rare case of triple thyroid ectopia

    PubMed Central

    Rahalkar, Mukund; Rahalkar, Anand; Solav, Shrikant

    2014-01-01

    Various anomalies of thyro-glossal duct have been described, in which the duct may form a cyst or may present as a solid nodule to form an ectopic gland. The ectopic gland can develop along the tract of the duct to give rise to ectopic lingual, sublingual (pre-hyoid) or sub-hyoid (pyramidal) gland, with or without normal pre-tracheal thyroid gland.There are a few reports of double ectopia of thyroid but triple ectopia of thyroid is extremely rare. We have come across a case of triple thyroid ectopia, i.e., thyroid tissue at three locations along the tract of descent of thyro-glossal duct on CT, which hast been rarely reported in the world literature, and hence this report. PMID:24741526

  3. Optimal timing for managed relocation of species faced with climate change

    USGS Publications Warehouse

    McDonald Madden, Eve; Runge, Michael C.; Possingham, Hugh P.; Martin, Tara G.

    2011-01-01

    Managed relocation is a controversial climate-adaptation strategy to combat negative climate change impacts on biodiversity. While the scientific community debates the merits of managed relocation, species are already being moved to new areas predicted to be more suitable under climate change. To inform these moves, we construct a quantitative decision framework to evaluate the timing of relocation in the face of climate change. We find that the optimal timing depends on many factors, including the size of the population, the demographic costs of translocation and the expected carrying capacities over time in the source and destination habitats. In some settings, such as when a small population would benefit from time to grow before risking translocation losses, haste is ill advised. We also find that active adaptive management is valuable when the effect of climate change on source habitat is uncertain, and leads to delayed movement.

  4. Large-eddy simulation of flow around an airfoil on a structured mesh

    NASA Technical Reports Server (NTRS)

    Kaltenbach, Hans-Jakob; Choi, Haecheon

    1995-01-01

    The diversity of flow characteristics encountered in a flow over an airfoil near maximum lift taxes the presently available statistical turbulence models. This work describes our first attempt to apply the technique of large-eddy simulation to a flow of aeronautical interest. The challenge for this simulation comes from the high Reynolds number of the flow as well as the variety of flow regimes encountered, including a thin laminar boundary layer at the nose, transition, boundary layer growth under adverse pressure gradient, incipient separation near the trailing edge, and merging of two shear layers at the trailing edge. The flow configuration chosen is a NACA 4412 airfoil near maximum lift. The corresponding angle of attack was determined independently by Wadcock (1987) and Hastings & Williams (1984, 1987) to be close to 12 deg. The simulation matches the chord Reynolds number U(sub infinity)c/v = 1.64 x 10(exp 6) of Wadcock's experiment.

  5. Bayesian phylogeny analysis via stochastic approximation Monte Carlo.

    PubMed

    Cheon, Sooyoung; Liang, Faming

    2009-11-01

    Monte Carlo methods have received much attention in the recent literature of phylogeny analysis. However, the conventional Markov chain Monte Carlo algorithms, such as the Metropolis-Hastings algorithm, tend to get trapped in a local mode in simulating from the posterior distribution of phylogenetic trees, rendering the inference ineffective. In this paper, we apply an advanced Monte Carlo algorithm, the stochastic approximation Monte Carlo algorithm, to Bayesian phylogeny analysis. Our method is compared with two popular Bayesian phylogeny software, BAMBE and MrBayes, on simulated and real datasets. The numerical results indicate that our method outperforms BAMBE and MrBayes. Among the three methods, SAMC produces the consensus trees which have the highest similarity to the true trees, and the model parameter estimates which have the smallest mean square errors, but costs the least CPU time.

  6. The neighborhood MCMC sampler for learning Bayesian networks

    NASA Astrophysics Data System (ADS)

    Alyami, Salem A.; Azad, A. K. M.; Keith, Jonathan M.

    2016-07-01

    Getting stuck in local maxima is a problem that arises while learning Bayesian networks (BNs) structures. In this paper, we studied a recently proposed Markov chain Monte Carlo (MCMC) sampler, called the Neighbourhood sampler (NS), and examined how efficiently it can sample BNs when local maxima are present. We assume that a posterior distribution f(N,E|D) has been defined, where D represents data relevant to the inference, N and E are the sets of nodes and directed edges, respectively. We illustrate the new approach by sampling from such a distribution, and inferring BNs. The simulations conducted in this paper show that the new learning approach substantially avoids getting stuck in local modes of the distribution, and achieves a more rapid rate of convergence, compared to other common algorithms e.g. the MCMC Metropolis-Hastings sampler.

  7. Religious voices in biotechnology: the case of gene patenting.

    PubMed

    Hanson, M J

    1999-01-01

    On 18 May 1995, nearly 200 religious leaders joined with leading biotechnology critic Jeremy Rifkin in a press conference named the "Joint Appeal against Human and Animal Patenting," a move that many within the biotechnology industry could only interpret as seeking to inhibit biotechnological advance. What moral and religious concerns motivated this challenge to patenting? How could the biotechnology industry understand and respectfully attend to these concerns? What values were at play in the debates that followed the joint appeal? What lessons for future dialogue can be learned from attempts at conversation between the opposing positions? This essay is a report from a Hastings Center research project that accepted the task of addressing these questions. Specifically, the project focused on the patenting of human genetic material, a subset of the issues raised by the joint appeal.

  8. Modeling association among demographic parameters in analysis of open population capture-recapture data

    USGS Publications Warehouse

    Link, William A.; Barker, Richard J.

    2005-01-01

    We present a hierarchical extension of the Cormack–Jolly–Seber (CJS) model for open population capture–recapture data. In addition to recaptures of marked animals, we model first captures of animals and losses on capture. The parameter set includes capture probabilities, survival rates, and birth rates. The survival rates and birth rates are treated as a random sample from a bivariate distribution, thus the model explicitly incorporates correlation in these demographic rates. A key feature of the model is that the likelihood function, which includes a CJS model factor, is expressed entirely in terms of identifiable parameters; losses on capture can be factored out of the model. Since the computational complexity of classical likelihood methods is prohibitive, we use Markov chain Monte Carlo in a Bayesian analysis. We describe an efficient candidate-generation scheme for Metropolis–Hastings sampling of CJS models and extensions. The procedure is illustrated using mark-recapture data for the moth Gonodontis bidentata.

  9. Monte Carlo methods for light propagation in biological tissues.

    PubMed

    Vinckenbosch, Laura; Lacaux, Céline; Tindel, Samy; Thomassin, Magalie; Obara, Tiphaine

    2015-11-01

    Light propagation in turbid media is driven by the equation of radiative transfer. We give a formal probabilistic representation of its solution in the framework of biological tissues and we implement algorithms based on Monte Carlo methods in order to estimate the quantity of light that is received by a homogeneous tissue when emitted by an optic fiber. A variance reduction method is studied and implemented, as well as a Markov chain Monte Carlo method based on the Metropolis-Hastings algorithm. The resulting estimating methods are then compared to the so-called Wang-Prahl (or Wang) method. Finally, the formal representation allows to derive a non-linear optimization algorithm close to Levenberg-Marquardt that is used for the estimation of the scattering and absorption coefficients of the tissue from measurements.

  10. Cellular Automata Models of Ring Dynamics

    NASA Astrophysics Data System (ADS)

    Gravner, Janko

    This paper describes three models arising from the theory of excitable media, whose primary visual feature are expanding rings of excitation. Rigorous mathematical results and experimental/computational issues are both addressed. We start with the much-studied Greenberg-Hastings model (GHM) in which the rings are very short-lived, but they do have a transient percolation property. By contrast, in the model we call annihilating nested rings (ANR), excitation centers only gradually lose strength, i.e., each time they become inactive (and then stay so forever) with a fixed probability; we show how the long-term global connectivity properties of the set of excited sites undergo a phase transition. Second part of the paper is devoted to digital boiling (DB) in which new rings spontaneously appear at rested sites with a positive probability. We focus on such (related) issues as convergence to equilibrium, equilibrium excitation level and success of the basic coupling.

  11. Cellular automata models of ring dynamics

    SciTech Connect

    Gravner, J.

    1996-12-01

    This paper describes three models arising from the theory of excitable media, whose primary visual feature are expanding rings of excitation. Rigorous mathematical results and experimental/computational issues are both addressed. We start with the much-studied Greenberg-Hastings model (GHM) in which the rings are very short-lived, but they do have a transient percolation property. By contrast, in the model we call annihilating nested rings (ANR), excitation centers only gradually lose strength, i.e., each time they become inactive (and then stay so forever) with a fixed probability; we show how the long-term global connectivity properties of the set of excited sites undergo a phase transition. Second part of the paper is devoted to digital boiling (DB) in which new rings spontaneously appear at rested sites with a positive probability. We focus on such (related) issues as convergence to equilibrium, equilibrium excitation level and success of the basic coupling.

  12. Multiple imputation for high-dimensional mixed incomplete continuous and binary data.

    PubMed

    He, Ren; Belin, Thomas

    2014-06-15

    It is common in applied research to have large numbers of variables measured on a modest number of cases. Even with low rates of missingness of individual variables, such data sets can have a large number of incomplete cases with a mix of data types. Here, we propose a new joint modeling approach to address the high-dimensional incomplete data with a mix of continuous and binary data. Specifically, we propose a multivariate normal model encompassing both continuous variables and latent variables corresponding to binary variables. We apply a parameter-extended Metropolis–Hastings algorithm to generate the covariance matrix of a mixture of continuous and binary variables. We also introduce prior distribution families for unstructured covariance matrices to reduce the dimension of the parameter space. In several simulation settings, the method is compared with available-case analysis, a rounding method, and a sequential regression method.

  13. Application of Thermo-Mechanical Measurements of Plastic Packages for Reliability Evaluation of PEMS

    NASA Technical Reports Server (NTRS)

    Sharma, Ashok K.; Teverovsky, Alexander

    2004-01-01

    Thermo-mechanical analysis (TMA) is typically employed for measurements of the glass transition temperature (Tg) and coefficients of thermal expansion (CTE) in molding compounds used in plastic encapsulated microcircuits (PEMs). Application of TMA measurements directly to PEMs allows anomalies to be revealed in deformation of packages with temperature, and thus indicates possible reliability concerns related to thermo-mechanical integrity and stability of the devices. In this work, temperature dependencies of package deformation were measured in several types of PEMs that failed environmental stress testing including temperature cycling, highly accelerated stress testing (HAST) in humid environments, and bum-in (BI) testing. Comparison of thermo-mechanical characteristics of packages and molding compounds in the failed parts allowed for explanation of the observed failures. The results indicate that TMA of plastic packages might be used for quality evaluation of PEMs intended for high-reliability applications.

  14. Phase-Change Modelling in Severe Nuclear Accidents

    NASA Astrophysics Data System (ADS)

    Pain, Christopher; Pavlidis, Dimitrios; Xie, Zhihua; Percival, James; Gomes, Jefferson; Matar, Omar; Moatamedi, Moji; Tehrani, Ali; Jones, Alan; Smith, Paul

    2014-11-01

    This paper describes progress on a consistent approach for multi-phase flow modelling with phase-change. Although, the developed methods are general purpose the applications presented here cover core melt phenomena at the lower vessel head. These include corium pool formation, coolability and solidification. With respect to external cooling, comparison with the LIVE experiments (from Karlsruhe) is undertaken. Preliminary re-flooding simulation results are also presented. These include water injection into porous media (debris bed) and boiling. Numerical simulations follow IRSN's PEARL experimental programme on quenching/re-flooding. The authors wish to thank Prof. Timothy Haste of IRSN. Dr. D. Pavlidis is funded by EPSRC Consortium ``Computational Modelling for Advanced Nuclear Plants,'' Grant Number EP/I003010/1.

  15. Small Commercial Program DOE Project: Impact evaluation. Final report

    SciTech Connect

    Bathgate, R.; Faust, S.

    1992-08-12

    In 1991, Washington Electric Cooperative (WEC) implemented a Department of Energy grant to conduct a small commercial energy conservation project. The small commercial ``Mom, and Pop`` grocery stores within WEC`s service territory were selected as the target market for the project. Energy & Solid Waste Consultant`s (E&SWC) Impact Evaluation is documented here. The evaluation was based on data gathered from a variety of sources, including load profile metering, kWh submeters, elapsed time indicators, and billing histories. Five stores were selected to receive measures under this program: Waits River General Store, Joe`s Pond Store, Hastings Store, Walden General Store, and Adamant Cooperative. Specific measures installed in each store and description of each are included.

  16. Small Commercial Program DOE Project: Impact evaluation

    SciTech Connect

    Bathgate, R.; Faust, S. )

    1992-08-12

    In 1991, Washington Electric Cooperative (WEC) implemented a Department of Energy grant to conduct a small commercial energy conservation project. The small commercial Mom, and Pop'' grocery stores within WEC's service territory were selected as the target market for the project. Energy Solid Waste Consultant's (E SWC) Impact Evaluation is documented here. The evaluation was based on data gathered from a variety of sources, including load profile metering, kWh submeters, elapsed time indicators, and billing histories. Five stores were selected to receive measures under this program: Waits River General Store, Joe's Pond Store, Hastings Store, Walden General Store, and Adamant Cooperative. Specific measures installed in each store and description of each are included.

  17. Lessons not yet learned from the Fukushima disaster

    NASA Astrophysics Data System (ADS)

    Klügel, Jens-Uwe

    2014-05-01

    The Fukushima nuclear catastrophe has led to a wide-spread international discussion on how seismic and tsunami hazards can be better predicted and adverse consequences be prevented.In some countries the event led to the complete phase-out of nuclear energy. The lessons drawn by different organisations including earth scientists, earthquake engineers,non-governmental and governmental organisations will be reviewed from an independent position. This review captures the following areas: 1) Hazard assessment 2) Engineering design and defense in depth concepts 3) Emergency preparedness It is shown that not all important lessons from the catastrophe have been drawn. Especially the need of an holistic approach towards hazard assessment and the implementation of defense in depth and diversity of design principles for critical infrastructures like nuclear power plants hast to be stronger emphasized to prevent similar disasters.

  18. Magnetic resonance imaging of acoustic streaming: absorption coefficient and acoustic field shape estimation.

    PubMed

    Madelin, Guillaume; Grucker, Daniel; Franconi, Jean-Michel; Thiaudiere, Eric

    2006-07-01

    In this study, magnetic resonance imaging (MRI) is used to visualize acoustic streaming in liquids. A single-shot spin echo sequence (HASTE) with a saturation band perpendicular to the acoustic beam permits the acquisition of an instantaneous image of the flow due to the application of ultrasound. An average acoustic streaming velocity can be estimated from the MR images, from which the ultrasonic absorption coefficient and the bulk viscosity of different glycerol-water mixtures can be deduced. In the same way, this MRI method could be used to assess the acoustic field and time-average power of ultrasonic transducers in water (or other liquids with known physical properties), after calibration of a geometrical parameter that is dependent on the experimental setup.

  19. Water-quality assessment of part of the Upper Mississippi River Basin Study Unit, Minnesota and Wisconsin- Nutrients, chlorophyll a, phytoplankton, and suspended sediment in streams, 1996-98

    USGS Publications Warehouse

    Kroening, Sharon E.; Lee, Kathy E.; Goldstein, R.M.

    2003-01-01

    The greatest chlorophyll-a concentrations and algal abundances generally were measured in the Little Cobb River near Beauford, Minnesota; Minnesota River near Jordan, Minnesota; Mississippi River at Hastings, Minnesota; and the Mississippi River at Red Wing, Minnesota. Greater concentrations and algal abundances at these sites may have been the result of increased nitrogen and phosphorus concentrations. Total phosphorus concentrations at these sites most frequently exceeded the goal of 0.1 mg/L set by the USEPA to prevent eutrophication. Phytoplankton communities at these sites primarily were dominated by blue-green algae during the summer of 1996. In contrast, at most of the other sites, the phytoplankton community was dominated by diatoms.

  20. Replica state exchange metadynamics for improving the convergence of free energy estimates.

    PubMed

    Galvelis, Raimondas; Sugita, Yuji

    2015-07-15

    Metadynamics (MTD) is a powerful enhanced sampling method for systems with rugged energy landscapes. It constructs a bias potential in a predefined collective variable (CV) space to overcome barriers between metastable states. In bias-exchange MTD (BE-MTD), multiple replicas approximate the CV space by exchanging bias potentials (replica conditions) with the Metropolis-Hastings (MH) algorithm. We demonstrate that the replica-exchange rates and the convergence of free energy estimates of BE-MTD are improved by introducing the infinite swapping (IS) or the Suwa-Todo (ST) algorithms. Conceptually, IS and ST perform transitions in a replica state space rather than exchanges in a replica condition space. To emphasize this, the proposed scheme is called the replica state exchange MTD (RSE-MTD). Benchmarks were performed with alanine polypeptides in vacuum and water. For the systems tested in this work, there is no significant performance difference between IS and ST.

  1. Generalized Dynamic Factor Models for Mixed-Measurement Time Series

    PubMed Central

    Cui, Kai; Dunson, David B.

    2013-01-01

    In this article, we propose generalized Bayesian dynamic factor models for jointly modeling mixed-measurement time series. The framework allows mixed-scale measurements associated with each time series, with different measurements having different distributions in the exponential family conditionally on time-varying latent factor(s). Efficient Bayesian computational algorithms are developed for posterior inference on both the latent factors and model parameters, based on a Metropolis Hastings algorithm with adaptive proposals. The algorithm relies on a Greedy Density Kernel Approximation (GDKA) and parameter expansion with latent factor normalization. We tested the framework and algorithms in simulated studies and applied them to the analysis of intertwined credit and recovery risk for Moody’s rated firms from 1982–2008, illustrating the importance of jointly modeling mixed-measurement time series. The article has supplemental materials available online. PMID:24791133

  2. Light cone matrix product

    SciTech Connect

    Hastings, Matthew B

    2009-01-01

    We show how to combine the light-cone and matrix product algorithms to simulate quantum systems far from equilibrium for long times. For the case of the XXZ spin chain at {Delta} = 0.5, we simulate to a time of {approx} 22.5. While part of the long simulation time is due to the use of the light-cone method, we also describe a modification of the infinite time-evolving bond decimation algorithm with improved numerical stability, and we describe how to incorporate symmetry into this algorithm. While statistical sampling error means that we are not yet able to make a definite statement, the behavior of the simulation at long times indicates the appearance of either 'revivals' in the order parameter as predicted by Hastings and Levitov (e-print arXiv:0806.4283) or of a distinct shoulder in the decay of the order parameter.

  3. Poland: biomedical ethics in a socialist state.

    PubMed

    Szawarski, Zbigniew

    1987-06-01

    In one of a Hastings Center Report series of four country reports, a professor of ethics discusses the Polish approach to ethical issues in health care. Szawarski begins by outlining five factors that influence the practice of medicine in Poland: a socialist form of government, the influence of the Roman Catholic Church, an ongoing economic crisis, the legacy of the Nazi death camps, and a lack of formal instruction in biomedical ethics. He then discusses three current ethical concerns of physicians, patients, and the public: regulation of physician conduct, abortion, and in vitro fertilization. There is little formal public debate of the issues, however, and physicians seem committed to upholding traditional medical codes of ethics without analyzing underlying moral principles and justifications.

  4. Bayesian evidence computation for model selection in non-linear geoacoustic inference problems.

    PubMed

    Dettmer, Jan; Dosso, Stan E; Osler, John C

    2010-12-01

    This paper applies a general Bayesian inference approach, based on Bayesian evidence computation, to geoacoustic inversion of interface-wave dispersion data. Quantitative model selection is carried out by computing the evidence (normalizing constants) for several model parameterizations using annealed importance sampling. The resulting posterior probability density estimate is compared to estimates obtained from Metropolis-Hastings sampling to ensure consistent results. The approach is applied to invert interface-wave dispersion data collected on the Scotian Shelf, off the east coast of Canada for the sediment shear-wave velocity profile. Results are consistent with previous work on these data but extend the analysis to a rigorous approach including model selection and uncertainty analysis. The results are also consistent with core samples and seismic reflection measurements carried out in the area.

  5. Semiparametric Bayesian inference on skew-normal joint modeling of multivariate longitudinal and survival data.

    PubMed

    Tang, An-Min; Tang, Nian-Sheng

    2015-02-28

    We propose a semiparametric multivariate skew-normal joint model for multivariate longitudinal and multivariate survival data. One main feature of the posited model is that we relax the commonly used normality assumption for random effects and within-subject error by using a centered Dirichlet process prior to specify the random effects distribution and using a multivariate skew-normal distribution to specify the within-subject error distribution and model trajectory functions of longitudinal responses semiparametrically. A Bayesian approach is proposed to simultaneously obtain Bayesian estimates of unknown parameters, random effects and nonparametric functions by combining the Gibbs sampler and the Metropolis-Hastings algorithm. Particularly, a Bayesian local influence approach is developed to assess the effect of minor perturbations to within-subject measurement error and random effects. Several simulation studies and an example are presented to illustrate the proposed methodologies.

  6. In the ruins of Babel: pitfalls on the way toward a universal language for research ethics and benefit sharing.

    PubMed

    Solbakk, Jan Helge

    2011-07-01

    At the end of a paper on international research ethics published in the July-August 2010 issue of the Hastings Center Report, London and Zollman argue the need for grounding our duties in international medical and health-related research within a broader normative framework of social, distributive, and rectificatory justice. The same goes for Thomas Pogge, who, in a whole range of publications during the past years, has argued for a human-rights-based approach to international research. In a thought-provoking paper in the June 2010 issue of the American Journal of Bioethics, Angela J. Ballantyne argues that “the global bioethics priority” in medical and health-related research ethics today is how to do research fairly in an unjust world.

  7. A Bayesian Approach to Learning Scoring Systems.

    PubMed

    Ertekin, Şeyda; Rudin, Cynthia

    2015-12-01

    We present a Bayesian method for building scoring systems, which are linear models with coefficients that have very few significant digits. Usually the construction of scoring systems involve manual effort-humans invent the full scoring system without using data, or they choose how logistic regression coefficients should be scaled and rounded to produce a scoring system. These kinds of heuristics lead to suboptimal solutions. Our approach is different in that humans need only specify the prior over what the coefficients should look like, and the scoring system is learned from data. For this approach, we provide a Metropolis-Hastings sampler that tends to pull the coefficient values toward their "natural scale." Empirically, the proposed method achieves a high degree of interpretability of the models while maintaining competitive generalization performances.

  8. Robustness of the Critical Behaviour in a Discrete Stochastic Reaction-Diffusion Medium

    NASA Astrophysics Data System (ADS)

    Fatès, Nazim; Berry, Hugues

    We study the steady states of a reaction-diffusion medium modelled by a stochastic 2D cellular automaton. We consider the Greenberg-Hastings model where noise and topological irregularities of the grid are taken into account. The decrease of the probability of excitation changes qualitatively the behaviour of the system from an "active" to an "extinct" steady state. Simulations show that this change occurs near a critical threshold; it is identified as a nonequilibrium phase transition which belongs to the directed percolation universality class. We test the robustness of the phenomenon by introducing persistent defects in the topology : directed percolation behaviour is conserved. Using experimental and analytical tools, we suggest that the critical threshold varies as the inverse of the average number of neighbours per cell.

  9. Applying diffusion-based Markov chain Monte Carlo

    PubMed Central

    Paul, Rajib; Berliner, L. Mark

    2017-01-01

    We examine the performance of a strategy for Markov chain Monte Carlo (MCMC) developed by simulating a discrete approximation to a stochastic differential equation (SDE). We refer to the approach as diffusion MCMC. A variety of motivations for the approach are reviewed in the context of Bayesian analysis. In particular, implementation of diffusion MCMC is very simple to set-up, even in the presence of nonlinear models and non-conjugate priors. Also, it requires comparatively little problem-specific tuning. We implement the algorithm and assess its performance for both a test case and a glaciological application. Our results demonstrate that in some settings, diffusion MCMC is a faster alternative to a general Metropolis-Hastings algorithm. PMID:28301529

  10. Reproductive technology: in the Netherlands, tolerance and debate.

    PubMed

    De Wachter, Maurice A M; De Wert, Guido MWR

    1987-06-01

    Two ethicists from the Netherlands' Institute for Bioethics file a report on their country in one of six Hastings Center Report articles on the status of reproductive technologies around the world. The situation in the Netherlands reflects the tolerant attitudes of the Dutch toward what are regarded as private matters. Artificial insemination, in vitro fertilization, and surrogate motherhood are available, and research on embryos is in the planning stages. Facilities offering reproductive services are regulated by the Minister of Health, with advice from the independent Health Council on Artificial Reproduction, the National Council for Public Health, and various insurance companies and professional medical organizations. Public policy debates center around such issues as the value of parenthood; involvement of third parties; secrecy about a child's genetic origins; privacy for semen, ovum, and embryo donors; access to services; and insurance coverage of treatment.

  11. Generalized Dynamic Factor Models for Mixed-Measurement Time Series.

    PubMed

    Cui, Kai; Dunson, David B

    2014-02-12

    In this article, we propose generalized Bayesian dynamic factor models for jointly modeling mixed-measurement time series. The framework allows mixed-scale measurements associated with each time series, with different measurements having different distributions in the exponential family conditionally on time-varying latent factor(s). Efficient Bayesian computational algorithms are developed for posterior inference on both the latent factors and model parameters, based on a Metropolis Hastings algorithm with adaptive proposals. The algorithm relies on a Greedy Density Kernel Approximation (GDKA) and parameter expansion with latent factor normalization. We tested the framework and algorithms in simulated studies and applied them to the analysis of intertwined credit and recovery risk for Moody's rated firms from 1982-2008, illustrating the importance of jointly modeling mixed-measurement time series. The article has supplemental materials available online.

  12. Dynamic range of hypercubic stochastic excitable media

    NASA Astrophysics Data System (ADS)

    Assis, Vladimir R. V.; Copelli, Mauro

    2008-01-01

    We study the response properties of d -dimensional hypercubic excitable networks to a stochastic stimulus. Each site, modeled either by a three-state stochastic susceptible-infected-recovered-susceptible system or by the probabilistic Greenberg-Hastings cellular automaton, is continuously and independently stimulated by an external Poisson rate h . The response function (mean density of active sites ρ versus h ) is obtained via simulations (for d=1,2,3,4 ) and mean-field approximations at the single-site and pair levels (∀d) . In any dimension, the dynamic range and sensitivity of the response function are maximized precisely at the nonequilibrium phase transition to self-sustained activity, in agreement with a reasoning recently proposed. Moreover, the maximum dynamic range attained at a given dimension d is a decreasing function of d .

  13. Bayesian Inference for Duplication–Mutation with Complementarity Network Models

    PubMed Central

    Persing, Adam; Beskos, Alexandros; Heine, Kari; De Iorio, Maria

    2015-01-01

    Abstract We observe an undirected graph G without multiple edges and self-loops, which is to represent a protein–protein interaction (PPI) network. We assume that G evolved under the duplication–mutation with complementarity (DMC) model from a seed graph, G0, and we also observe the binary forest Γ that represents the duplication history of G. A posterior density for the DMC model parameters is established, and we outline a sampling strategy by which one can perform Bayesian inference; that sampling strategy employs a particle marginal Metropolis–Hastings (PMMH) algorithm. We test our methodology on numerical examples to demonstrate a high accuracy and precision in the inference of the DMC model's mutation and homodimerization parameters. PMID:26355682

  14. Markov Chain Monte Carlo from Lagrangian Dynamics

    PubMed Central

    Lan, Shiwei; Stathopoulos, Vasileios; Shahbaba, Babak; Girolami, Mark

    2014-01-01

    Hamiltonian Monte Carlo (HMC) improves the computational e ciency of the Metropolis-Hastings algorithm by reducing its random walk behavior. Riemannian HMC (RHMC) further improves the performance of HMC by exploiting the geometric properties of the parameter space. However, the geometric integrator used for RHMC involves implicit equations that require fixed-point iterations. In some cases, the computational overhead for solving implicit equations undermines RHMC's benefits. In an attempt to circumvent this problem, we propose an explicit integrator that replaces the momentum variable in RHMC by velocity. We show that the resulting transformation is equivalent to transforming Riemannian Hamiltonian dynamics to Lagrangian dynamics. Experimental results suggests that our method improves RHMC's overall computational e ciency in the cases considered. All computer programs and data sets are available online (http://www.ics.uci.edu/~babaks/Site/Codes.html) in order to allow replication of the results reported in this paper. PMID:26240515

  15. Molecular dynamics simulations of field emission from a planar nanodiode

    SciTech Connect

    Torfason, Kristinn; Valfells, Agust; Manolescu, Andrei

    2015-03-15

    High resolution molecular dynamics simulations with full Coulomb interactions of electrons are used to investigate field emission in planar nanodiodes. The effects of space-charge and emitter radius are examined and compared to previous results concerning transition from Fowler-Nordheim to Child-Langmuir current [Y. Y. Lau, Y. Liu, and R. K. Parker, Phys. Plasmas 1, 2082 (1994) and Y. Feng and J. P. Verboncoeur, Phys. Plasmas 13, 073105 (2006)]. The Fowler-Nordheim law is used to determine the current density injected into the system and the Metropolis-Hastings algorithm to find a favourable point of emission on the emitter surface. A simple fluid like model is also developed and its results are in qualitative agreement with the simulations.

  16. Clinical utility of EEG in attention deficit hyperactivity disorder.

    PubMed

    Loo, Sandra K; Barkley, Russell A

    2005-01-01

    Electrophysiological measures were among the first to be used to study brain processes in children with attention deficit hyperactivity disorder (ADHD; Diagnostic and Statistical Manual of Mental Disorders [4th ed.], American Psychiatric Association, 1994) and have been used as such for over 30 years (see Hastings & Barkley, 1978, for an early review). More recently, electroencephalography (EEG) has been used both in research to describe and quantify the underlying neurophysiology of ADHD, but also clinically in the assessment, diagnosis, and treatment of ADHD. This review will first provide a brief overview of EEG and then present some of the research findings of EEG correlates in ADHD. Then, the utility of EEG in making an ADHD diagnosis and predicting stimulant response will be examined. Finally, and more controversially, we will review the results of the most recent studies on EEG biofeedback (neurofeedback) as a treatment for ADHD and the issues that remain to be addressed in the research examining the efficacy this therapeutic approach.

  17. Adaptive Metropolis Sampling with Product Distributions

    NASA Technical Reports Server (NTRS)

    Wolpert, David H.; Lee, Chiu Fan

    2005-01-01

    The Metropolis-Hastings (MH) algorithm is a way to sample a provided target distribution pi(z). It works by repeatedly sampling a separate proposal distribution T(x,x') to generate a random walk {x(t)}. We consider a modification of the MH algorithm in which T is dynamically updated during the walk. The update at time t uses the {x(t' less than t)} to estimate the product distribution that has the least Kullback-Leibler distance to pi. That estimate is the information-theoretically optimal mean-field approximation to pi. We demonstrate through computer experiments that our algorithm produces samples that are superior to those of the conventional MH algorithm.

  18. The Lake Charles CCS Project

    SciTech Connect

    Doug Cathro

    2010-06-30

    The Lake Charles CCS Project is a large-scale industrial carbon capture and sequestration (CCS) project which will demonstrate advanced technologies that capture and sequester carbon dioxide (CO{sub 2}) emissions from industrial sources into underground formations. Specifically the Lake Charles CCS Project will accelerate commercialization of large-scale CO{sub 2} storage from industrial sources by leveraging synergy between a proposed petroleum coke to chemicals plant (the LCC Gasification Project) and the largest integrated anthropogenic CO{sub 2} capture, transport, and monitored sequestration program in the U.S. Gulf Coast Region. The Lake Charles CCS Project will promote the expansion of EOR in Texas and Louisiana and supply greater energy security by expanding domestic energy supplies. The capture, compression, pipeline, injection, and monitoring infrastructure will continue to sequester CO{sub 2} for many years after the completion of the term of the DOE agreement. The objectives of this project are expected to be fulfilled by working through two distinct phases. The overall objective of Phase 1 was to develop a fully definitive project basis for a competitive Renewal Application process to proceed into Phase 2 - Design, Construction and Operations. Phase 1 includes the studies attached hereto that will establish: the engineering design basis for the capture, compression and transportation of CO{sub 2} from the LCC Gasification Project, and the criteria and specifications for a monitoring, verification and accounting (MVA) plan at the Hastings oil field in Texas. The overall objective of Phase 2, provided a successful competitive down-selection, is to execute design, construction and operations of three capital projects: (1) the CO{sub 2} capture and compression equipment, (2) a Connector Pipeline from the LLC Gasification Project to the Green Pipeline owned by Denbury and an affiliate of Denbury, and (3) a comprehensive MVA system at the Hastings oil field.

  19. TU-F-BRF-06: 3D Pancreas MRI Segmentation Using Dictionary Learning and Manifold Clustering

    SciTech Connect

    Gou, S; Rapacchi, S; Hu, P; Sheng, K

    2014-06-15

    Purpose: The recent advent of MRI guided radiotherapy machines has lent an exciting platform for soft tissue target localization during treatment. However, tools to efficiently utilize MRI images for such purpose have not been developed. Specifically, to efficiently quantify the organ motion, we develop an automated segmentation method using dictionary learning and manifold clustering (DLMC). Methods: Fast 3D HASTE and VIBE MR images of 2 healthy volunteers and 3 patients were acquired. A bounding box was defined to include pancreas and surrounding normal organs including the liver, duodenum and stomach. The first slice of the MRI was used for dictionary learning based on mean-shift clustering and K-SVD sparse representation. Subsequent images were iteratively reconstructed until the error is less than a preset threshold. The preliminarily segmentation was subject to the constraints of manifold clustering. The segmentation results were compared with the mean shift merging (MSM), level set (LS) and manual segmentation methods. Results: DLMC resulted in consistently higher accuracy and robustness than comparing methods. Using manual contours as the ground truth, the mean Dices indices for all subjects are 0.54, 0.56 and 0.67 for MSM, LS and DLMC, respectively based on the HASTE image. The mean Dices indices are 0.70, 0.77 and 0.79 for the three methods based on VIBE images. DLMC is clearly more robust on the patients with the diseased pancreas while LS and MSM tend to over-segment the pancreas. DLMC also achieved higher sensitivity (0.80) and specificity (0.99) combining both imaging techniques. LS achieved equivalent sensitivity on VIBE images but was more computationally inefficient. Conclusion: We showed that pancreas and surrounding normal organs can be reliably segmented based on fast MRI using DLMC. This method will facilitate both planning volume definition and imaging guidance during treatment.

  20. Application of Magnetic Resonance Imaging to Measure Fasting and Postprandial Volumes in Humans

    PubMed Central

    Fidler, Jeff; Bharucha, Adil E.; Camilleri, Michael; Camp, Jon; Burton, Duane; Grimm, Roger; Riederer, Stephen J.; Robb, Richard A.; Zinsmeister, Alan R.

    2008-01-01

    Our aims were to measure the gastric volume response in excess of ingested meal volume (i.e., gastric accommodation), contribution of swallowed air to this excess, day-to-day variability of gastric volumes measured by MRI and their relationship to volumes measured by single-photon-emission computed tomography (SPECT). In 20 healthy volunteers, fasting and postprandial gastric volumes were measured after technetium99m-pertechnetate labeling of the gastric mucosa by SPECT and separately by MRI, using 3D gradient echo and 2D half-Fourier acquisition single-shot turbo spin echo (HASTE) sequences. Ten of these subjects had a second MRI exam to assess intra-individual variation. Thereafter, another 10 subjects had 2 MRI studies during which they ingested the nutrient in 30 or 150 mL aliquots. During MRI, the postprandial gastric volume change exceeded the ingested meal volume by 106 ± 12 mL (Mean ± SEM). The HASTE and gradient echo sequences distinguished air from fluid under fasting and postprandial conditions respectively. This postprandial excess mainly comprised air (61 ± 5 mL), which was not significantly different when ingested as 30 mL or 150 mL aliquots. Fasting and postprandial gastric volumes measured by MRI were generally reproducible within subjects. During SPECT, postprandial volumes increased by 158 ± 18 mL; gastric volumes measured by SPECT were higher than MRI. MRI measures gastric volumes with acceptable performance characteristics; the postprandial excess primarily consists of air, which is not affected by the mode of ingestion. Gastric volumes are technique specific and differ between MRI and SPECT. PMID:19019018

  1. MR Imaging of Pulmonary Nodules: Detection Rate and Accuracy of Size Estimation in Comparison to Computed Tomography

    PubMed Central

    Cieszanowski, Andrzej; Lisowska, Antonina; Dabrowska, Marta; Korczynski, Piotr; Zukowska, Malgorzata; Grudzinski, Ireneusz P.; Pacho, Ryszard; Rowinski, Olgierd; Krenke, Rafal

    2016-01-01

    Objective The aims of this study were to assess the sensitivity of various magnetic resonance imaging (MRI) sequences for the diagnosis of pulmonary nodules and to estimate the accuracy of MRI for the measurement of lesion size, as compared to computed tomography (CT). Methods Fifty patients with 113 pulmonary nodules diagnosed by CT underwent lung MRI and CT. MRI studies were performed on 1.5T scanner using the following sequences: T2-TSE, T2-SPIR, T2-STIR, T2-HASTE, T1-VIBE, and T1-out-of-phase. CT and MRI data were analyzed independently by two radiologists. Results The overall sensitivity of MRI for the detection of pulmonary nodules was 80.5% and according to nodule size: 57.1% for nodules ≤4mm, 75% for nodules >4-6mm, 87.5% for nodules >6-8mm and 100% for nodules >8mm. MRI sequences yielded following sensitivities: 69% (T1-VIBE), 54.9% (T2-SPIR), 48.7% (T2-TSE), 48.7% (T1-out-of-phase), 45.1% (T2-STIR), 25.7% (T2-HASTE), respectively. There was very strong agreement between the maximum diameter of pulmonary nodules measured by CT and MRI (mean difference -0.02 mm; 95% CI –1.6–1.57 mm; Bland-Altman analysis). Conclusions MRI yielded high sensitivity for the detection of pulmonary nodules and enabled accurate assessment of their diameter. Therefore it may be considered an alternative to CT for follow-up of some lung lesions. However, due to significant number of false positive diagnoses, it is not ready to replace CT as a tool for lung nodule detection. PMID:27258047

  2. Detection and molecular characterization of diarrhea causing viruses in single and mixed infections in children: a comparative study between Bangladesh and Turkey.

    PubMed

    Mitui, Marcelo Takahiro; Bozdayi, Gulendam; Ahmed, Selim; Matsumoto, Takashi; Nishizono, Akira; Ahmed, Kamruddin

    2014-07-01

    The incidence and mortality caused by diarrhea differ among countries. The prevalence of different enteric viruses, their molecular characteristics, and infections with multiple viruses might affect the disease incidence and mortality caused by diarrhea. The objective of this study was to determine the distribution and molecular characteristics of enteric viruses in children with diarrhea in Turkey and Bangladesh. A total of 288 stool samples that were negative for group A rotavirus were collected from children aged <5 years with acute diarrhea who presented to hospitals in Turkey and Bangladesh. The samples were screened for human bocavirus (HBoV), astrovirus (HAstV), norovirus (NoV), and adenovirus (AdV). Phylogenetic analyses of the targeted virus genes were performed. In Turkey, viruses were detected in 87/150 samples (58%), which included 69 (79.3%) with single viruses and 18 (20.7%) with multiple viruses. AdV was the most common virus, followed by HBoV. In Bangladesh, viruses were detected in 123/138 samples (89.1%), which included 29 (23.6%) with single viruses and 94 (76.4%) with multiple viruses. NoV GII was the most common, followed by AdV. The dominant genotypes among the virus species were HBoV 2A, HAstV 1, NoV GI type 1, and AdV 40. For NoV GII, the Hunter variant of genotype 4 in Turkey and genotype 17 in Bangladesh were the most common among the sequenced strains. It was concluded that the distribution of the viruses associated with diarrhea in Turkish and Bangladeshi children was different. Enteric viruses and mixed infections were more prevalent in Bangladesh than in Turkey.

  3. Does telephone triage of emergency (999) calls using advanced medical priority dispatch (AMPDS) with Department of Health (DH) call prioritisation effectively identify patients with an acute coronary syndrome? An audit of 42 657 emergency calls to Hampshire Ambulance Service NHS Trust

    PubMed Central

    Deakin, C D; Sherwood, D M; Smith, A; Cassidy, M

    2006-01-01

    Introduction The National Service Framework for Coronary Heart Disease requires identification of patients with an acute coronary syndrome (ACS) to enable prompt identification of those who may subsequently require pre‐hospital thrombolysis. The Advanced Medical Priority Despatch System (AMPDS) with Department of Health (DH) call prioritisation is now the common triage tool for emergency (‘999') calls in the UK. We retrospectively examined patients with ACS to identify whether this triage tool had been able to allocate an appropriate emergency response. Methods All emergency calls to Hampshire Ambulance Service NHS Trust (HAST) from the Southampton area over an 8 month period (January to August 2004) were analysed. The classification allocated to the patient by AMPDS (version 10.4) was specifically identified. Data from the Myocardial Infarct National Audit Project) were obtained from the receiving hospital in Southampton to identify the actual number of patients with a true ACS. Results In total, 42 657 emergency calls were made to HAST from the Southampton area. Of these, 263 patients were subsequently diagnosed in hospital as having an ACS. Of these 263 patients, 76 presented without chest pain. Sensitivity of AMPDS for detecting ACS in this sample was 71.1% and specificity 92.5%. Positive predictive value was 5.6% (95% confidence interval 4.8 to 6.4%), and 12.5% (33/263) of patients with confirmed ACS were classified as non‐life threatening (category B) incidents. Conclusion Only one of approximately every 18 patients with chest pain has an ACS. AMPDS with DH call prioritisation is not a tool designed for clinical diagnosis, and its extension into this field does not enable accurate identification of patients with ACS. PMID:16498168

  4. Structural inversion of the Tamworth Belt: Insights into the development of orogenic curvature in the southern New England Orogen, Australia

    NASA Astrophysics Data System (ADS)

    Phillips, G.; Robinson, J.; Glen, R.; Roberts, J.

    2016-05-01

    The middle to late Permian Hunter Bowen Event is credited with the development of orogenic curvature in the southern New England Orogen, yet contention surrounds the structural dynamics responsible for the development of this curvature. Debate is largely centred on the roles of orogen parallel strike-slip and orogen normal extension and contraction to explain the development of curvature. To evaluate the dynamic history of the Hunter Bowen Event, we present new kinematic reconstructions of the Tamworth Belt. The Tamworth Belt formed as a Carboniferous forearc basin and was subsequently inverted during the Hunter Bowen Event. Kinematic reconstructions of the Tamworth Belt are based on new maps and cross-sections built from a synthesis of best-available mapping, chronostratigraphic data and new interpretations of depth-converted seismic data. The following conclusions are made from our study: (i) the Hunter Bowen Event was dominantly driven by margin normal contraction (east-west shortening; present-day coordinates), and; (ii) variations in structural style along the strike of the Tamworth Belt can be explained by orthogonal vs. oblique inversion, which reflects the angular relationship between the principal shortening vector and continental-arc margin. Given these conclusions, we suggest that curvature around the controversial Manning Bend was influenced by the presence of primary curvature in the continental margin, and that the Hastings Block was translated along a sinistral strike-slip fault system that formed along this oblique (with respect to the regional east-west extension and convergence direction) part of the margin. Given the available temporal data, the translation of the Hastings Block took place in the Early Permian (Asselian) and therefore preceded the Hunter Bowen Event. Accordingly, we suggest that the Hunter Bowen Event was dominantly associated with enhancing curvature that was either primary in origin, or associated with fault block translation

  5. Evaluation of Data Retention and Imprint Characteristics of FRAMs Under Environmental Stresses for NASA Applications

    NASA Technical Reports Server (NTRS)

    Sharma, Asbok K.; Teverovsky, Alexander; Dowdy, Terry W.; Hamilton, Brett

    2002-01-01

    A major reliability issue for all advanced nonvolatile memory (NVM) technology devices including FRAMs is the data retention characteristics over extended period of time, under environmental stresses and exposure to total ionizing dose (TID) radiation effects. For this testing, 256 Kb FRAMs in 28-pin plastic DIPS, rated for industrial grade temperature range of -40 C to +85 C, were procured. These are two-transistor, two-capacitor (2T-2C) design FRAMs. In addition to data retention characteristics, the parts were also evaluated for imprint failures, which are defined as the failure of cells to change from a "preferred" state, where it has been for a significant period of time to an opposite state (e.g., from 1 to 0, or 0 to 1). These 256 K FRAMs were subjected to scanning acoustic microscopy (C-SAM); 1,000 temperature cycles from -65 C to +150 C; high temperature aging at 150 C, 175 C, and 200 C for 1,000 hours; highly accelerated stress test (HAST) for 500 hours; 1,000 hours of operational life test at 125 C; and total ionizing dose radiation testing. As a preconditioning, 10 K read/write cycles were performed on all devices. Interim electrical measurements were performed throughout this characterization, including special imprint testing and final electrical testing. Some failures were observed during high temperature aging test at 200 C, during HAST testing, and during 1,000 hours of operational life at 125 C. The parts passed 10 Krad exposure, but began showing power supply current increases during the dose increment from 10 Krad to 30 Krad, and at 40 Krad severe data retention and parametric failures were observed. Failures from various environmental group testing are currently being analyzed.

  6. Evaluation of Data Retention and Imprint Characteristics of FRAMs Under Environmental Stresses for NASA Applications

    NASA Technical Reports Server (NTRS)

    Sharma, Ashok K.; Teverovsky, Alexander; Dowdy, Terry W.; Hamilton, Brett

    2000-01-01

    A major reliability issue for all advanced nonvolatile memory (NVM) technology devices including FRAMs (Ferroelectric random access memories) is the data retention characteristics over extended period of time, under environmental stresses and exposure to total ionizing dose (TID) radiation effects. For this testing, 256 Kb FRAMs in 28-pin plastic DIPS, rated for industrial grade temperature range of -40 C to +85 C, were procured. These are two-transistor, two-capacitor (2T-2C) design FRAMs. In addition to data retention characteristics, the parts were also evaluated for imprint failures, which are defined as the failure of cells to change from a "preferred" state, where it has been for a significant period of time to an opposite state (e.g., from 1 to 0, or 0 to 1). These 256 K FRAMs were subjected to scanning acoustic microscopy (C-SAM); 1,000 temperature cycles from -65 C to +150 C; high temperature aging at 150 C, 175 C, and 200 C for 1,000 hours; highly accelerated stress test (HAST) for 500 hours; 1,000 hours of operational life test at 125 C; and total ionizing dose radiation testing. As a preconditioning, 10 K read/write cycles were performed on all devices. Interim electrical measurements were performed throughout this characterization, including special imprint testing and final electrical testing. Some failures were observed during high temperature aging test at 200 C, during HAST testing, and during 1,000 hours of operational life at 125 C. The parts passed 10 Krad exposure, but began showing power supply current increases during the dose increment from 10 Krad to 30 Krad, and at 40 Krad severe data retention and parametric failures were observed. Failures from various environmental group testing are currently being analyzed.

  7. Fetal Central Nervous System Anomalies Detected by Magnetic Resonance Imaging: A Two-Year Experience

    PubMed Central

    Sefidbakht, Sepideh; Dehghani, Sakineh; Safari, Maryam; Vafaei, Homeira; Kasraeian, Maryam

    2016-01-01

    Background Magnetic resonance imaging (MRI) is gradually becoming more common for thorough visualization of the fetus than ultrasound (US), especially for neurological anomalies, which are the most common indications for fetal MRI and are a matter of concern for both families and society. Objectives We investigated fetal MRIs carried out in our center for frequency of central nervous system anomalies. This is the first such report in southern Iran. Materials and Methods One hundred and seven (107) pregnant women with suspicious fetal anomalies in prenatal ultrasound entered a cross-sectional retrospective study from 2011 to 2013. A 1.5 T Siemens Avanto scanner was employed for sequences, including T2 HASTE and Trufisp images in axial, coronal, and sagittal planes to mother’s body, T2 HASTE and Trufisp relative to the specific fetal body part being evaluated, and T1 flash images in at least one plane based on clinical indication. We investigated any abnormality in the central nervous system and performed descriptive analysis to achieve index of frequency. Results Mean gestational age ± standard deviation (SD) for fetuses was 25.54 ± 5.22 weeks, and mean maternal age ± SD was 28.38 ± 5.80 years Eighty out of 107 (74.7%) patients who were referred with initial impression of borderline ventriculomegaly. A total of 18 out of 107 (16.82%) patients were found to have fetuses with CNS anomalies and the remainder were neurologically normal. Detected anomalies were as follow: 3 (16.6%) fetuses each had the Dandy-Walker variant and Arnold-Chiari II (with myelomeningocele). Complete agenesis of corpus callosum, partial agenesis of corpus callosum, and aqueductal stenosis were each seen in 2 (11.1%) fetuses. Arnold-Chiari II without myelomeningocele, anterior spina bifida associated with neurenteric cyst, arachnoid cyst, lissencephaly, and isolated enlarged cisterna magna each presented in one (5.5%) fetus. One fetus had concomitant schizencephaly and complete agenesis of

  8. Exotic ingredients in the mélange at Port Macquarie, southern New England Orogen, reveal a spicy history of crustal kneading along eastern Gondwana

    NASA Astrophysics Data System (ADS)

    Buckman, S.; Nutman, A.

    2013-12-01

    (sinistral) displacement of the Port Macquarie and Hastings Blocks and the dextral displacement of the Coffs Harbour Block associated with the Texas orocline, is apparent only, and due more in part to vertical displacements of an extensive, thin-skinned oceanic terranes that underlie the Tablelands Complex, rather than extensive lateral movements. Thus, there is no need to invoke large-scale ';oroclinal' folding or significant sinistral faulting to explain the repetition of Hastings and Port Macquarie blocks in the southern New England.

  9. Drowning of a barrier coastline under rapid rates of relative sea-level rise during the 8.2 ka cooling event: Cause or coincidence?

    NASA Astrophysics Data System (ADS)

    Mellett, C.; Hodgson, D. M.; Lang, A.; Mauz, B.; Plater, A. J.

    2012-12-01

    Examples where barrier landforms and deposits are preserved offshore of a highstand shoreline are rare on contemporary continental shelves, and in the rock record. Therefore, understanding of the conditions required for preservation and the sedimentary processes-response to such factors is limited and heavily dependent on simulation models. Here, an integrated dataset of multibeam bathymetry and 2D seismic reflection profiles has uncovered an exceptionally well preserved drowned barrier complex at Hastings Bank, on the English Channel continental shelf, offshore of southeast England. Mapping of nine seismic stratigraphic units calibrated with lithological information from multiple vibrocores has enabled the interpretation of fluvial, shoreface, barrier, washover fan, back-barrier and tidal environments of deposition. Stratigraphic architecture is used as the basis for landscape evolution reconstructions that reveal phases of barrier progradation, degradation and retreat. Optical Stimulated Luminescence (OSL) dating of shoreface and beach deposits revealed ages in the range of 8.4 ± 0.2 ka and 7.8 ± 0.2 ka. These ages indicate the barrier developed under rapid rates of early Holocene sea-level rise and more specifically, correlate to the time period surrounding the 8.2 ka cooling event and associated sea-level 'jump'. To preserve a barrier beach including the barrier foreshore under such rapid rates of relative sea-level rise, sediment supply would have to be sufficient to keep pace to prevent the shoreline responding through continuous reworking, i.e. rollover. Further, the rate of transgression is conditioned by inherited topography with higher rates of retreat, and hence greater potential for drowning, expected across the shallowly dipping substrate. Using Hastings Bank as an example, it has also been demonstrated that the morphodynamic state of the barrier complex in terms of its ability to respond dynamically to relative sea-level rise, conditions its

  10. Saline as the Sole Contrast Agent for Successful MRI-guided Epidural Injections

    SciTech Connect

    Deli, Martin; Mateiescu, Serban Busch, Martin; Becker, Jan Garmer, Marietta Groenemeyer, Dietrich

    2013-06-15

    Purpose. To assess the performance of sterile saline solution as the sole contrast agent for percutaneous magnetic resonance imaging (MRI)-guided epidural injections at 1.5 T. Methods. A retrospective analysis of two different techniques of MRI-guided epidural injections was performed with either gadolinium-enhanced saline solution or sterile saline solution for documentation of the epidural location of the needle tip. T1-weighted spoiled gradient echo (FLASH) images or T2-weighted single-shot turbo spin echo (HASTE) images visualized the test injectants. Methods were compared by technical success rate, image quality, table time, and rate of complications. Results. 105 MRI-guided epidural injections (12 of 105 with gadolinium-enhanced saline solution and 93 of 105 with sterile saline solution) were performed successfully and without complications. Visualization of sterile saline solution and gadolinium-enhanced saline solution was sufficient, good, or excellent in all 105 interventions. For either test injectant, quantitative image analysis demonstrated comparable high contrast-to-noise ratios of test injectants to adjacent body substances with reliable statistical significance levels (p < 0.001). The mean table time was 22 {+-} 9 min in the gadolinium-enhanced saline solution group and 22 {+-} 8 min in the saline solution group (p = 0.75). Conclusion. Sterile saline is suitable as the sole contrast agent for successful and safe percutaneous MRI-guided epidural drug delivery at 1.5 T.

  11. Progeria: pathogenesis and oral manifestation--a review.

    PubMed

    Saigal, S; Bhargava, A

    2012-01-01

    Our life span is genetically programmed and it is possible that a defect in produced proteins encoded by the longevity gene is a cause of aging. Progeria which is a rare, fatal genetic condition which affects between one in four million and one in eight million children of both sexes equally and characterized by premature and accelerated aging. The appearance and physiology of these children resembles to elderly people but they typically have life span to their mid teens. It is also known as the Hutchinson-Gilford syndrome, which was initially reported by Johnathan Hutchinson in 1886 and further described by Hastings Gilford in 1904. It is an autosomal recessive disorder, which means an individual has inherited a mutated gene from both parents. It is added to the expanding catalogue of laminopathies, diseases caused by mutations affecting nuclear lamina proteins known as lamin A (LMNA). In oral manifestation primary finding is micrognathia with delayed tooth eruption and incomplete formation of root of permanent tooth. Presently there are no known cures for this abnormality.

  12. Investigation of - and Post-Seismic Signals in GRACE Satellite Gravity Data Using Mcmc Approach

    NASA Astrophysics Data System (ADS)

    Mikhailov, V. O.; Hayn, M.; Pollitz, F. F.; Panet, I.; Holschneider, M.; Diament, M.

    2013-12-01

    Earthquakes cause mass shifts and stress-dependent density changes. The corresponding gravity field variations can be measured by the GRACE satellites what was demonstrated for recent Andaman-Sumatra (2004), Maule, Chili (2010) and Tohoku-Oki (2011) earthquakes. In contrast to other data, satellite gravity regularly covers continental and oceanic areas, providing important information about the seismic cycle, especially in subduction zones. We make use of the characteristic temporal behavior and spatial scale of the earthquake signals, in order to separate them from other contributions to the gravity field. This is realized by wavelet transform and application of a time evolution model. The later consists of a step function followed by an exponential decay, representing co- and post-seismic variations. As the problem is nonlinear, parameters were fitted by determining their posterior distribution by means of a Markov-Chain Metropolis-Hasting sampling. As a result, we clearly separate the co- and post-seismic gravity variations for all three abovementioned earthquakes. We also apply the method to separate post-seismic signals from the Andaman-Sumatra and Nias-Sumatra events. The later occurred 3 months later to the south of the main megathrust event. These results are compared with other geophysical data and models. This allows to discriminate between candidate models for the co-seismic gravity variations using GPS data and seismology, and to better understand the physical processes involved in the post-seismic deformation.

  13. A multi-thermogram-based Bayesian model for the determination of the thermal diffusivity of a material

    NASA Astrophysics Data System (ADS)

    Allard, Alexandre; Fischer, Nicolas; Ebrard, Géraldine; Hay, Bruno; Harris, Peter; Wright, Louise; Rochais, Denis; Mattout, Jeremie

    2016-02-01

    The determination of thermal diffusivity is at the heart of modern materials characterisation. The evaluation of the associated uncertainty is difficult because the determination is performed in an indirect way, in the sense that the thermal diffusivity cannot be measured directly. The well-known GUM uncertainty framework does not provide a reliable evaluation of measurement uncertainty for such inverse problems, because in that framework the underlying measurement model is supposed to be a direct relationship between the measurand (the quantity intended to be measured) and the input quantities on which the measurand depends. This paper is concerned with the development of a Bayesian approach to evaluate the measurement uncertainty associated with thermal diffusivity. A Bayesian model is first developed for a single thermogram and is then extended to the case of several thermograms obtained under repeatability and reproducibility conditions. This multi-thermogram based model is able to take into consideration a large set of influencing quantities that occur during the measurements and yields a more reliable uncertainty evaluation than the one obtained from a single thermogram. Different aspects of the Bayesian model are discussed, including the sensitivity to the choice of the prior distribution, the Metropolis-Hastings algorithm used for the inference and the convergence of the Markov chains.

  14. Rape and the prevalence of hybrids in broadly sympatric species: a case study using albatrosses.

    PubMed

    Rohwer, Sievert; Harris, Rebecca B; Walsh, Hollie E

    2014-01-01

    Conspecific rape often increases male reproductive success. However, the haste and aggression of forced copulations suggests that males may sometimes rape heterospecific females, thus making rape a likely, but undocumented, source of hybrids between broadly sympatric species. We present evidence that heterospecific rape may be the source of hybrids between Black-footed and Laysan Albatrosses (Phoebastria nigripes, and P. immutabilis, respectively). Extensive field studies have shown that paired (but not unpaired) males of both of these albatross species use rape as a supplemental reproductive strategy. Between species differences in size, timing of laying, and aggressiveness suggest that Black-footed Albatrosses should be more successful than Laysan Albatrosses in heteropspecific rape attempts, and male Black-footed Albatrosses have been observed attempting to force copulations on female Laysan Albatrosses. Nuclear markers showed that the six hybrids we studied were F1s and mitochondrial markers showed that male Black-footed Albatrosses sired all six hybrids. Long-term gene exchange between these species has been from Black-footed Albatrosses into Laysan Albatrosses, suggesting that the siring asymmetry found in our hybrids has long persisted. If hybrids are sired in heterospecific rapes, they presumably would be raised and sexually imprinted on Laysan Albatrosses, and two unmated hybrids in a previous study courted only Laysan Albatrosses.

  15. Alternative Test Methods for Electronic Parts

    NASA Technical Reports Server (NTRS)

    Plante, Jeannette

    2004-01-01

    It is common practice within NASA to test electronic parts at the manufacturing lot level to demonstrate, statistically, that parts from the lot tested will not fail in service using generic application conditions. The test methods and the generic application conditions used have been developed over the years through cooperation between NASA, DoD, and industry in order to establish a common set of standard practices. These common practices, found in MIL-STD-883, MIL-STD-750, military part specifications, EEE-INST-002, and other guidelines are preferred because they are considered to be effective and repeatable and their results are usually straightforward to interpret. These practices can sometimes be unavailable to some NASA projects due to special application conditions that must be addressed, such as schedule constraints, cost constraints, logistical constraints, or advances in the technology that make the historical standards an inappropriate choice for establishing part performance and reliability. Alternate methods have begun to emerge and to be used by NASA programs to test parts individually or as part of a system, especially when standard lot tests cannot be applied. Four alternate screening methods will be discussed in this paper: Highly accelerated life test (HALT), forward voltage drop tests for evaluating wire-bond integrity, burn-in options during or after highly accelerated stress test (HAST), and board-level qualification.

  16. Continuous cotemporal probabilistic modeling of systems biology networks from sparse data.

    PubMed

    John, David J; Fetrow, Jacquelyn S; Norris, James L

    2011-01-01

    Modeling of biological networks is a difficult endeavor, but exploration of this problem is essential for understanding the systems behavior of biological processes. In this contribution, developed for sparse data, we present a new continuous Bayesian graphical learning algorithm to cotemporally model proteins in signaling networks and genes in transcriptional regulatory networks. In this continuous Bayesian algorithm, the correlation matrix is singular because the number of time points is less than the number of biological entities (genes or proteins). A suitable restriction on the degree of the graph's vertices is applied and a Metropolis-Hastings algorithm is guided by a BIC-based posterior probability score. Ten independent and diverse runs of the algorithm are conducted, so that the probability space is properly well-explored. Diagnostics to test the applicability of the algorithm to the specific data sets are developed; this is a major benefit of the methodology. This novel algorithm is applied to two time course experimental data sets: 1) protein modification data identifying a potential signaling network in chondrocytes, and 2) gene expression data identifying the transcriptional regulatory network underlying dendritic cell maturation. This method gives high estimated posterior probabilities to many of the proteins' directed edges that are predicted by the literature; for the gene study, the method gives high posterior probabilities to many of the literature-predicted sibling edges. In simulations, the method gives substantially higher estimated posterior probabilities for true edges and true subnetworks than for their false counterparts.

  17. Antimalarial hybrid molecules: a close reality or a distant dream?

    PubMed

    Agarwal, Drishti; Gupta, Rinkoo D; Awasthi, Satish K

    2017-03-13

    Emergence of drug resistant Plasmodium falciparum strains has led to a situation of haste in the scientific and pharmaceutical communities. Hence, all their efforts are redirected towards finding alternate chemotherapeutic agents that are capable of combating multi-drug resistant parasite strains. In the above light, scientists have come up with the concept of hybridisation of two or more active pharmacophores into a single chemical entity, resulting in 'antimalarial hybrids.' The approach has been applied widely for lead generation against deadly diseases such as cancer and AIDS, with proven potential to be used as novel drugs, but is comparatively new in the sphere of antimalarial drug discovery. A sudden surge has been evidenced in the number of studies on design and synthesis of hybrids for treating malaria, and may be regarded as proof of their potential advantages over Artemisinin based Combination Therapy (ACT). However, it is evident from recent studies that most of the potential advantages of antimalarial hybrids, such as lower toxicity, better pharmacokinetics and easier formulation, have yet to be realised. A number of questions left unaddressed at present need to be answered before this approach can progress in to the late stages of clinical development and prove their worth in the clinic. To the best of our knowledge, this compilation is the first attempt to shed light over the shortcomings that are surfacing as more and more studies on molecular hybridization of the active pharmacophores of known antimalarials are being published.

  18. A Flexible Method of Estimating Luminosity Functions

    NASA Astrophysics Data System (ADS)

    Kelly, Brandon C.; Fan, Xiaohui; Vestergaard, Marianne

    2008-08-01

    We describe a Bayesian approach to estimating luminosity functions. We derive the likelihood function and posterior probability distribution for the luminosity function, given the observed data, and we compare the Bayesian approach with maximum likelihood by simulating sources from a Schechter function. For our simulations confidence intervals derived from bootstrapping the maximum likelihood estimate can be too narrow, while confidence intervals derived from the Bayesian approach are valid. We develop our statistical approach for a flexible model where the luminosity function is modeled as a mixture of Gaussian functions. Statistical inference is performed using Markov chain Monte Carlo (MCMC) methods, and we describe a Metropolis-Hastings algorithm to perform the MCMC. The MCMC simulates random draws from the probability distribution of the luminosity function parameters, given the data, and we use a simulated data set to show how these random draws may be used to estimate the probability distribution for the luminosity function. In addition, we show how the MCMC output may be used to estimate the probability distribution of any quantities derived from the luminosity function, such as the peak in the space density of quasars. The Bayesian method we develop has the advantage that it is able to place accurate constraints on the luminosity function even beyond the survey detection limits, and that it provides a natural way of estimating the probability distribution of any quantities derived from the luminosity function, including those that rely on information beyond the survey detection limits.

  19. Effects of altitude, distance and waves of movement on the dispersal in Australia of the arbovirus vector, Culicoides brevitarsis Kieffer (Diptera: Ceratopogonidae).

    PubMed

    Bishop, Alan L; Spohr, Lorraine J; Barchia, Idris M

    2004-10-14

    The dispersal of the biting midge and arbovirus vector Culicoides brevitarsis in the Bellinger, Macleay and Hastings river valleys and up the escarpment of the great dividing range (GDR) of mid-northern coastal New South Wales, Australia, from 1995 to 2003 was studied. The midge moved up these valleys from the endemic coastal plain in at least two waves between October and May, and both waves were modelled. Dispersal time can be explained by direct distance from the coast and the altitude of the sites. Dispersal times due to distance were similar at 18.2 +/- 2.2 (S.D.) and 15.9 +/- 2.6 weeks per 100 km for first- and second-occurrences at fixed altitude. Time of the first wave was extended 0.48 +/- 0.22 weeks for every 100-m rise in altitude and the second by 1.14 +/- 0.24 weeks for every 100-m rise for a set distance. Although C. brevitarsis can move up the escarpment of the GDR (and possibly transmit virus), vector dispersal, survival and establishment at and beyond the top of the range are limited. A third model showed that previously described slower movement of C. brevitarsis up the more-southerly Hunter valley relative to movements down the coastal plain also was related to increasing altitude.

  20. Improving Bayesian analysis for LISA Pathfinder using an efficient Markov Chain Monte Carlo method

    NASA Astrophysics Data System (ADS)

    Ferraioli, Luigi; Porter, Edward K.; Armano, Michele; Audley, Heather; Congedo, Giuseppe; Diepholz, Ingo; Gibert, Ferran; Hewitson, Martin; Hueller, Mauro; Karnesis, Nikolaos; Korsakova, Natalia; Nofrarias, Miquel; Plagnol, Eric; Vitale, Stefano

    2014-02-01

    We present a parameter estimation procedure based on a Bayesian framework by applying a Markov Chain Monte Carlo algorithm to the calibration of the dynamical parameters of the LISA Pathfinder satellite. The method is based on the Metropolis-Hastings algorithm and a two-stage annealing treatment in order to ensure an effective exploration of the parameter space at the beginning of the chain. We compare two versions of the algorithm with an application to a LISA Pathfinder data analysis problem. The two algorithms share the same heating strategy but with one moving in coordinate directions using proposals from a multivariate Gaussian distribution, while the other uses the natural logarithm of some parameters and proposes jumps in the eigen-space of the Fisher Information matrix. The algorithm proposing jumps in the eigen-space of the Fisher Information matrix demonstrates a higher acceptance rate and a slightly better convergence towards the equilibrium parameter distributions in the application to LISA Pathfinder data. For this experiment, we return parameter values that are all within ˜1 σ of the injected values. When we analyse the accuracy of our parameter estimation in terms of the effect they have on the force-per-unit of mass noise, we find that the induced errors are three orders of magnitude less than the expected experimental uncertainty in the power spectral density.

  1. A Comparison of Homeless Male Veterans in Metropolitan and Micropolitan Areas in Nebraska: A Methodological Caveat.

    PubMed

    Tsai, Jack; Ramaswamy, Sriram; Bhatia, Subhash C; Rosenheck, Robert A

    2015-12-01

    This study explored differences between homeless male veterans in metropolitan and micropolitan cities in Nebraska on sociodemographic, housing, clinical, and psychosocial characteristics as well as health service use. A convenience sample of 151 homeless male veterans (112 metropolitan, 39 micropolitan) were recruited from Veterans Affairs facilities and area shelters in Omaha, Lincoln, Grand Island, and Hastings in Nebraska. Research staff conducted structured interviews with homeless veterans. Results showed that compared to homeless veterans in metropolitans, those in micropolitans were more likely to be White, unmarried, living in transitional settings, and were far more transient but reported greater social support and housing satisfaction. Veterans in micropolitans also reported more medical problems, diagnoses of anxiety and personality disorders, and unexpectedly, were more likely to report using various health services and less travel time for services. Together, these findings suggest access to homeless and health services for veterans in micropolitan areas may be facilitated through Veterans Affairs facilities and community providers that work in close proximity to one another. Many homeless veterans in these areas are transient, making them a difficult population to study and serve. Innovative ways to provide outreach to homeless veterans in micropolitan and more rural areas are needed.

  2. Bayesian analysis of the flutter margin method in aeroelasticity

    NASA Astrophysics Data System (ADS)

    Khalil, Mohammad; Poirel, Dominique; Sarkar, Abhijit

    2016-12-01

    A Bayesian statistical framework is presented for Zimmerman and Weissenburger flutter margin method which considers the uncertainties in aeroelastic modal parameters. The proposed methodology overcomes the limitations of the previously developed least-square based estimation technique which relies on the Gaussian approximation of the flutter margin probability density function (pdf). Using the measured free-decay responses at subcritical (preflutter) airspeeds, the joint non-Gaussain posterior pdf of the modal parameters is sampled using the Metropolis-Hastings (MH) Markov chain Monte Carlo (MCMC) algorithm. The posterior MCMC samples of the modal parameters are then used to obtain the flutter margin pdfs and finally the flutter speed pdf. The usefulness of the Bayesian flutter margin method is demonstrated using synthetic data generated from a two-degree-of-freedom pitch-plunge aeroelastic model. The robustness of the statistical framework is demonstrated using different sets of measurement data. It will be shown that the probabilistic (Bayesian) approach reduces the number of test points required in providing a flutter speed estimate for a given accuracy and precision.

  3. A non-enteric adenovirus A12 gastroenteritis outbreak in Rio de Janeiro, Brazil

    PubMed Central

    Portes, Silvana Augusta Rodrigues; Volotão, Eduardo de Mello; Rocha, Monica Simões; Rebelo, Maria Cristina; Xavier, Maria da Penha Trindade Pinheiro; de Assis, Rosane Maria; Rose, Tatiana Lundgren; Miagostovich, Marize Pereira; Leite, José Paulo Gagliardi; Carvalho-Costa, Filipe Anibal

    2016-01-01

    A gastroenteritis outbreak that occurred in 2013 in a low-income community in Rio de Janeiro was investigated for the presence of enteric viruses, including species A rotavirus (RVA), norovirus (NoV), astrovirus (HAstV), bocavirus (HBoV), aichivirus (AiV), and adenovirus (HAdV). Five of nine stool samples (83%) from patients were positive for HAdV, and no other enteric viruses were detected. Polymerase chain reaction products were sequenced and subjected to phylogenetic analysis, which revealed four strains and one strain of non-enteric HAdV-A12 and HAdV-F41, respectively. The HAdV-A12 nucleotide sequences shared 100% nucleotide similarity. Viral load was assessed using a TaqMan real-time PCR assay. Stool samples that were positive for HAdV-A12 had high viral loads (mean 1.9 X 107 DNA copies/g stool). All four patients with HAdV-A12 were < 25 months of age and had symptoms of fever and diarrhoea. Evaluation of enteric virus outbreaks allows the characterisation of novel or unique diarrhoea-associated viruses in regions where RVA vaccination is routinely performed. PMID:27223654

  4. Translational Symmetry and Microscopic Constraints on Symmetry-Enriched Topological Phases: A View from the Surface

    NASA Astrophysics Data System (ADS)

    Cheng, Meng; Zaletel, Michael; Barkeshli, Maissam; Vishwanath, Ashvin; Bonderson, Parsa

    2016-10-01

    The Lieb-Schultz-Mattis theorem and its higher-dimensional generalizations by Oshikawa and Hastings require that translationally invariant 2D spin systems with a half-integer spin per unit cell must either have a continuum of low energy excitations, spontaneously break some symmetries, or exhibit topological order with anyonic excitations. We establish a connection between these constraints and a remarkably similar set of constraints at the surface of a 3D interacting topological insulator. This, combined with recent work on symmetry-enriched topological phases with on-site unitary symmetries, enables us to develop a framework for understanding the structure of symmetry-enriched topological phases with both translational and on-site unitary symmetries, including the effective theory of symmetry defects. This framework places stringent constraints on the possible types of symmetry fractionalization that can occur in 2D systems whose unit cell contains fractional spin, fractional charge, or a projective representation of the symmetry group. As a concrete application, we determine when a topological phase must possess a "spinon" excitation, even in cases when spin rotational invariance is broken down to a discrete subgroup by the crystal structure. We also describe the phenomena of "anyonic spin-orbit coupling," which may arise from the interplay of translational and on-site symmetries. These include the possibility of on-site symmetry defect branch lines carrying topological charge per unit length and lattice dislocations inducing degeneracies protected by on-site symmetry.

  5. Coercivity enhancement of sintered Nd-Fe-B magnets by chemical bath deposition of TbCl{sub 3}

    SciTech Connect

    Guo, Shuai Zhang, Xiaofeng; Ding, Guangfei; Chen, Renjie; Yan, Aru; Lee, Don

    2014-05-07

    The chemical bath deposition (CBD) and the grain boundary diffusion method were combined to diffuse the heavy rare earth for obtain the thick magnets with high coercivity and low heavy rare earth. The jet mill powders were soaked into the alcohol solution of 0.2 wt. % TbCl{sub 3}. A thin layer of TbCl{sub 3} was wrapped to the surface of (PrNd){sub 2}Fe{sub 14}B powder particles. The coercivity of magnet is increased from 11.89 kOe to 14.72 kOe without significant reduction of remanence after grain boundary diffusion in the sintering and the annealing processes. The temperature coefficients of the remanence and the coercivity are improved by the substitution of PrNd by Tb in the surface of grains. The highly accelerated temperature/humidity stress test (HAST) results indicate that the CBD magnet has poor corrosion resistance, attributing to the present of Cl atoms in the grain boundaries.

  6. The Manhattan Frame Model - Manhattan World Inference in the Space of Surface Normals.

    PubMed

    Straub, Julian; Freifeld, Oren; Rosman, Guy; Leonard, John J; Fisher, John W

    2017-02-01

    Objects and structures within man-made environments typically exhibit a high degree of organization in the form of orthogonal and parallel planes. Traditional approaches utilize these regularities via the restrictive, and rather local, Manhattan World (MW) assumption which posits that every plane is perpendicular to one of the axes of a single coordinate system. The aforementioned regularities are especially evident in the surface normal distribution of a scene where they manifest as orthogonally-coupled clusters. This motivates the introduction of the Manhattan-Frame (MF) model which captures the notion of a MW in the surface normals space, the unit sphere, and two probabilistic MF models over this space. First, for a single MF we propose novel real-time MAP inference algorithms, evaluate their performance and their use in drift-free rotation estimation. Second, to capture the complexity of real-world scenes at a global scale, we extend the MF model to a probabilistic mixture of Manhattan Frames (MMF). For MMF inference we propose a simple MAP inference algorithm and an adaptive Markov-Chain Monte-Carlo sampling algorithm with Metropolis-Hastings split/merge moves that let us infer the unknown number of mixture components. We demonstrate the versatility of the MMF model and inference algorithm across several scales of man-made environments.

  7. Detecting non-transiting exoplanets

    NASA Astrophysics Data System (ADS)

    Placek, Ben; Richards, Zachary; Knuth, Kevin H.

    2013-08-01

    Currently, the most popular way of detecting Extra-solar planets (exoplanets) is via the Transit Method. This method is limited only to planets with orbits such that we observe them transiting their host star. In this work in progress, we propose to identify non-transiting exoplanets in the data currently being collected by the Kepler Space Telescope by detecting orbital phase reflected light variations. Since such variations are due to light from the host star reflected by the planet, we expect this method to work best on closely orbitting large planets. Using the Metropolis-Hastings Monte Carlo and Nested Sampling algorithms, we will determine the presence or absence of nontransiting planets and estimate their orbital parameters such as, orbital inclination, semi-major axis, period, and eccentricity. Our estimates indicate that the development of this technique has the potential to double the number of detectable planets in the Kepler data sets. Here we demonstrate feasibility using portions of data from one of the first transiting planets detected by Kepler, HAT-P-7b.

  8. Characterization of Interstellar Organic Molecules

    NASA Astrophysics Data System (ADS)

    Gençaǧa, Deniz; Carbon, Duane F.; Knuth, Kevin H.

    2008-11-01

    Understanding the origins of life has been one of the greatest dreams throughout history. It is now known that star-forming regions contain complex organic molecules, known as Polycyclic Aromatic Hydrocarbons (PAHs), each of which has particular infrared spectral characteristics. By understanding which PAH species are found in specific star-forming regions, we can better understand the biochemistry that takes place in interstellar clouds. Identifying and classifying PAHs is not an easy task: we can only observe a single superposition of PAH spectra at any given astrophysical site, with the PAH species perhaps numbering in the hundreds or even thousands. This is a challenging source separation problem since we have only one observation composed of numerous mixed sources. However, it is made easier with the help of a library of hundreds of PAH spectra. In order to separate PAH molecules from their mixture, we need to identify the specific species and their unique concentrations that would provide the given mixture. We develop a Bayesian approach for this problem where sources are separated from their mixture by Metropolis Hastings algorithm. Separated PAH concentrations are provided with their error bars, illustrating the uncertainties involved in the estimation process. The approach is demonstrated on synthetic spectral mixtures using spectral resolutions from the Infrared Space Observatory (ISO). Performance of the method is tested for different noise levels.

  9. Clinical epidemiology and molecular profiling of human bocavirus in faecal samples from children with diarrhoea in Guangzhou, China.

    PubMed

    Zhang, D-M; Ma, M-M; Wen, W-T; Zhu, X; Xu, L; He, Z-J; He, X; Wu, J-H; Hu, Y-W; Zheng, Y; Deng, Y; Lin, C-J; Lu, J-H; Li, M-F; Cao, K-Y

    2015-08-01

    To understand the clinical epidemiology and molecular characteristics of human bocavirus (HBoV) infection in children with diarrhoea in Guangzhou, South China, we collected 1128 faecal specimens from children with diarrhoea from July 2010 to December 2012. HBoV and five other major enteric viruses were examined using real-time polymerase chain reaction. Human rotavirus (HRV) was the most prevalent pathogen, detected in 250 (22·2%) cases, followed by enteric adenovirus (EADV) in 76 (6·7%) cases, human astrovirus (HAstV) in 38 (3·4%) cases, HBoV in 17 (1·5%) cases, sapovirus (SaV) in 14 (1·2%) cases, and norovirus (NoV) in 9 (0·8%) cases. Co-infections were identified in 3·7% of the study population and 23·5% of HBoV-positive specimens. Phylogenetic analysis revealed 14 HBoV strains to be clustered into species HBoV1 with only minor variations among them. Overall, the detection of HBoV appears to partially contribute to the overall detection gap for enteric infections, single HBoV infection rarely results in severe clinical outcomes, and HBoV sequencing data appears to support conserved genomes across strains identified in this study.

  10. Calibration of a distributed flood forecasting model with input uncertainty using a Bayesian framework

    NASA Astrophysics Data System (ADS)

    Li, Mingliang; Yang, Dawen; Chen, Jinsong; Hubbard, Susan S.

    2012-08-01

    In the process of calibrating distributed hydrological models, accounting for input uncertainty is important, yet challenging. In this study, we develop a Bayesian model to estimate parameters associated with a geomorphology-based hydrological model (GBHM). The GBHM model uses geomorphic characteristics to simplify model structure and physically based methods to represent hydrological processes. We divide the observed discharge into low- and high-flow data, and use the first-order autoregressive model to describe their temporal dependence. We consider relative errors in rainfall as spatially distributed variables and estimate them jointly with the GBHM parameters. The joint posterior probability distribution is explored using Markov chain Monte Carlo methods, which include Metropolis-Hastings, delay rejection adaptive Metropolis, and Gibbs sampling methods. We evaluate the Bayesian model using both synthetic and field data sets. The synthetic case study demonstrates that the developed method generally is effective in calibrating GBHM parameters and in estimating their associated uncertainty. The calibration ignoring input errors has lower accuracy and lower reliability compared to the calibration that includes estimation of the input errors, especially under model structure uncertainty. The field case study shows that calibration of GBHM parameters under complex field conditions remains a challenge. Although jointly estimating input errors and GBHM parameters improves the continuous ranked probability score and the consistency of the predictive distribution with the observed data, the improvement is incremental. To better calibrate parameters in a distributed model, such as GBHM here, we need to develop a more complex model and incorporate much more information.

  11. A high Reliability Module with Thermoelectric Device by Molding Technology for M2M Wireless Sensor Network

    NASA Astrophysics Data System (ADS)

    Nakagawa, K.; Tanaka, T.; Suzuki, T.

    2014-11-01

    This paper presents the fabrication of a new energy harvesting module that used the thermoelectric device (TED) by using molding technology. The output voltage per heater temperature of the TED module at 20 °C ambient temperature is 8mV/K and similar to the result with the aluminium heat sink which is almost the same fin size as the TED module. The accelerated environmental tests are performed on damp heat test that is an aging test under high temperature and high humidity, cold test and highly accelerated temperature and humidity stress test (HAST) for the purpose of evaluating the electrical reliability in harsh environments. Every result of tests indicates that the TED and circuit board can be properly protected from harsh temperature and humidity by using molding technology, because the output voltage of after tested modules is reduced by less than 5%.This study presents a novel fabrication method for a high reliability TED-installed module appropriate for Machine to Machine wireless sensor networks

  12. A high reliability module with thermoelectric device by molding technology for M2M wireless sensor network

    NASA Astrophysics Data System (ADS)

    Nakagawa, K.; Tanaka, T.; Suzuki, T.

    2015-10-01

    This paper presents the fabrication of a new energy harvesting module that uses a thermoelectric device (TED) by using molding technology. Through molding technology, the TED and circuit board can be properly protected and a heat-radiating fin structure can be simultaneously constructed. The output voltage per heater temperature of the TED module at 20 °C ambient temperature is 8 mV K-1, similar to the result with the aluminum heat sink which is almost the same fin size as the TED module. The accelerated environmental tests are performed on a damp heat test, which is an aging test under high temperature and high humidity, highly accelerated temperature, and humidity stress test (HAST) for the purpose of evaluating the electrical reliability in harsh environments, cold test and thermal cycle test to evaluate degrading characteristics by cycling through two temperatures. All test results indicate that the TED and circuit board can be properly protected from harsh temperature and humidity by using molding technology because the output voltage of after-tested modules is reduced by less than 5%. This study presents a novel fabrication method for a high reliability TED-installed module appropriate for Machine to Machine wireless sensor networks.

  13. Virtual Goods Recommendations in Virtual Worlds

    PubMed Central

    Chen, Kuan-Yu; Liao, Hsiu-Yu; Chen, Jyun-Hung; Liu, Duen-Ren

    2015-01-01

    Virtual worlds (VWs) are computer-simulated environments which allow users to create their own virtual character as an avatar. With the rapidly growing user volume in VWs, platform providers launch virtual goods in haste and stampede users to increase sales revenue. However, the rapidity of development incurs virtual unrelated items which will be difficult to remarket. It not only wastes virtual global companies' intelligence resources, but also makes it difficult for users to find suitable virtual goods fit for their virtual home in daily virtual life. In the VWs, users decorate their houses, visit others' homes, create families, host parties, and so forth. Users establish their social life circles through these activities. This research proposes a novel virtual goods recommendation method based on these social interactions. The contact strength and contact influence result from interactions with social neighbors and influence users' buying intention. Our research highlights the importance of social interactions in virtual goods recommendation. The experiment's data were retrieved from an online VW platform, and the results show that the proposed method, considering social interactions and social life circle, has better performance than existing recommendation methods. PMID:25834837

  14. Flow and chloride transport in the tidal Hudson River, NY

    USGS Publications Warehouse

    Weiss, Lawrence A.; Schaffranek, Raymond W.; de Vries, M. Peter

    1994-01-01

    A one-dimensional dynamic-flow model and a one-dimensional solute-transport model were used to evaluate the effects of hypothetical public-supply water withdrawals on saltwater intrusion in a 133-mile reach of the tidal Hudson River between Green Island dam, near Troy, N.Y., and Hastings-on-Hudson, N.Y. Regression techniques were used in analyses of current and extreme historical conditions, and numerical models were used to investigate the effect of various water withdrawals. Of four withdrawal scenarios investigated, simulations of a 27-day period during which discharges at Green Island dam averaged 7,090 ft3/s indicate that increasing the present Chelsea pumping-station withdrawal rate of 100 Mgal/d (million gallons per day) to 300 Mgal/d would have the least effect on upstream saltwater movement. A 90-day simulation, during which discharges at Green Island dam averaged 25,200 ft3/s, indicates that withdrawals of 1,940 Mgal/d at Chelsea would not measurably increase chloride concentrations at Chelsea under normal tidal and meteorological conditions, but withdrawals of twice that rate (3,880 Mgal/d) could increase the chloride concentration at Chelsea to 250 mg/L.

  15. Even an old technique is suitable in the molecular world of science: the everted sac preparation turns 60 years old.

    PubMed

    Hamilton, Kirk L

    2014-04-15

    An old proverb states "necessity is the mother of invention." This certainly holds true in science as one pursues research questions. Experimental techniques have evolved as scientists have asked more specific research questions. Indeed, techniques such as the Ussing chamber, the perfused renal tubule preparation, patch-clamp, polymerase chain reaction, and site-directed mutagenesis have been developed over the past 60 years. However, sometimes, simple techniques may be useful and still very informative, and this certainly applies to intestinal physiology. Indeed, Gerald Wiseman and Thomas Hastings Wilson described the intestinal everted sac preparation some 60 years ago. Since then, this technique has been used for numerous research purposes including determining ion, amino acid, water and solute transport across the intestinal epithelium; and drug metabolism, absorption, and interactions in pharmaceutical/pharmacological research and even in education. This article provides a historical review of the development of the in vitro intestinal preparation that led to the everted sac preparation and its use in science.

  16. Performance of Thermal Mass Flow Meters in a Variable Gravitational Environment

    NASA Technical Reports Server (NTRS)

    Brooker, John E.; Ruff, Gary A.

    2004-01-01

    The performance of five thermal mass flow meters, MKS Instruments 179A and 258C, Unit Instruments UFM-8100, Sierra Instruments 830L, and Hastings Instruments HFM-200, were tested on the KC-135 Reduced Gravity Aircraft in orthogonal, coparallel, and counterparallel orientations relative to gravity. Data was taken throughout the parabolic trajectory where the g-level varied from 0.01 to 1.8 times normal gravity. Each meter was calibrated in normal gravity in the orthogonal position prior to flight followed by ground testing at seven different flow conditions to establish a baseline operation. During the tests, the actual flow rate was measured independently using choked-flow orifices. Gravitational acceleration and attitude had a unique effect on the performance of each meter. All meters operated within acceptable limits at all gravity levels in the calibrated orthogonal position. However, when operated in other orientations, the deviations from the reference flow became substantial for several of the flow meters. Data analysis indicated that the greatest source of error was the effect of orientation, followed by the gravity level. This work emphasized that when operating thermal flow meters in a variable gravity environment, it is critical to orient the meter in the same direction relative to gravity in which it was calibrated. Unfortunately, there was no test in normal gravity that could predict the performance of a meter in reduced gravity. When operating in reduced gravity, all meters indicated within 5 percent of the full scale reading at all flow conditions and orientations.

  17. Preventable anesthesia mishaps: a study of human factors*

    PubMed Central

    Cooper, J.; Newbower, R.; Long, C.; McPeek, B.

    2002-01-01

    

 A modified critical-incident analysis technique was used in a retrospective examination of the characteristics of human error and equipment failure in anesthetic practice. The objective was to uncover patterns of frequently occurring incidents that are in need of careful prospective investigation. Forty seven interviews were conducted with staff and resident anesthesiologists at one urban teaching institution, and descriptions of 359 preventable incidents were obtained. Twenty three categories of details from these descriptions were subjected to computer-aided analysis for trends and patterns. Most of the preventable incidents involved human error (82%), with breathing-circuit disconnections, inadvertent changes in gas flow, and drug syringe errors being frequent problems. Overt equipment failures constituted only 14% of the total number of preventable incidents, but equipment design was indictable in many categories of human error, as were inadequate experience and insufficient familiarity with equipment or with the specific surgical procedure. Other factors frequently associated with incidents were inadequate communication among personnel, haste or lack of precaution, and distraction. Results from multi-hospital studies based on the methodology developed could be used for more objective determination of priorities and planning of specific investments for decreasing the risk associated with anesthesia. PMID:12486995

  18. Time-resolved visible and infrared absorption spectroscopy data obtained using photosystem I particles with non-native quinones incorporated into the A1 binding site.

    PubMed

    Makita, Hiroki; Hastings, Gary

    2016-06-01

    Time-resolved visible and infrared absorption difference spectroscopy data at both 298 and 77 K were obtained using cyanobacterial menB (-) mutant photosystem I particles with several non-native quinones incorporated into the A1 binding site. Data was obtained for photosystem I particles with phylloquinone (2-methyl-3-phytyl-1,4-naphthoquinone), 2-bromo-1,4-naphthoquinone, 2-chloro-1,4-naphthoquinone, 2-methyl-1,4-naphthoquinone, 2,3-dibromo-1,4-naphthoquinone, 2,3-dichloro-1,4-naphthoquinone, and 9,10-anthraquinone incorporated. Transient absorption data were obtained at 487 and 703 nm in the visible spectral range, and 1950-1100 cm(-1) in the infrared region. Time constants obtained from fitting the time-resolved infrared and visible data are in good agreement. The measured time constants are crucial for the development of appropriate kinetic models that can describe electron transfer processes in photosystem I, "Modeling Electron Transfer in Photosystem I" Makita and Hastings (2016) [1].

  19. Deep soil carbon dynamics are driven more by soil type than by climate: a worldwide meta-analysis of radiocarbon profiles.

    PubMed

    Mathieu, Jordane A; Hatté, Christine; Balesdent, Jérôme; Parent, Éric

    2015-11-01

    The response of soil carbon dynamics to climate and land-use change will affect both the future climate and the quality of ecosystems. Deep soil carbon (>20 cm) is the primary component of the soil carbon pool, but the dynamics of deep soil carbon remain poorly understood. Therefore, radiocarbon activity (Δ14C), which is a function of the age of carbon, may help to understand the rates of soil carbon biodegradation and stabilization. We analyzed the published 14C contents in 122 profiles of mineral soil that were well distributed in most of the large world biomes, except for the boreal zone. With a multivariate extension of a linear mixed-effects model whose inference was based on the parallel combination of two algorithms, the expectation-maximization (EM) and the Metropolis-Hasting algorithms, we expressed soil Δ14C profiles as a four-parameter function of depth. The four-parameter model produced insightful predictions of soil Δ14C as dependent on depth, soil type, climate, vegetation, land-use and date of sampling (R2=0.68). Further analysis with the model showed that the age of topsoil carbon was primarily affected by climate and cultivation. By contrast, the age of deep soil carbon was affected more by soil taxa than by climate and thus illustrated the strong dependence of soil carbon dynamics on other pedologic traits such as clay content and mineralogy.

  20. Molecular basis for the blue bioluminescence of the Australian glow-worm Arachnocampa richardsae (Diptera: Keroplatidae).

    PubMed

    Trowell, Stephen C; Dacres, Helen; Dumancic, Mira M; Leitch, Virginia; Rickards, Rodney W

    2016-09-16

    Bioluminescence is the emission of visible light by living organisms. Here we describe the isolation and characterisation of a cDNA encoding a MW ≈ 59,000 Da luciferase from the Australian glow-worm, Arachnocampa richardsae. The enzyme is a member of the acyl-CoA ligase superfamily and produces blue light on addition of D-luciferin. These results are contrary to earlier reports (Lee, J., Photochem Photobiol 24, 279-285 (1976), Viviani, V. R., Hastings, J. W. & Wilson, T., Photochem Photobiol 75, 22-27 (2002)), which suggested glow-worm luciferase has MW ≈ 36,000 Da and is unreactive with beetle luciferin. There are more than 2000 species of firefly, which all produce emissions from D-luciferin in the green to red regions of the electromagnetic spectrum. Although blue-emitting luciferases are known from marine organisms, they belong to different structural families and use a different substrate. The observation of blue emission from a D-luciferin-using enzyme is therefore unprecedented.

  1. Innovative Composite Wall System for Sheathing Masonry Walls

    SciTech Connect

    Wendt, Robert L.; Cavallo, James

    1997-09-25

    Existing Housing - Much of the older multifamily housing stock in the United States includes units in structures with uninsulated masonry walls. Included in this stock are two- and three-story walk-up apartments, larger apartment complexes, and public housing (both high- rise and townhouse). This older multifamily housing has seen years of heavy use that may have left the plaster wall marred or damaged. Long- term building settlement or movement may have cracked the plaster, sometimes severely. Moisture from invented kitchens and baths may have caused condensation on uninsulated exterior walls. At best this condensation has left stains on the paint or wallpaper. At worst it has supported mold and mildew growth, fouling the air and creating unhealthy living conditions. Deteriorating plaster and flaking paint also result from wet walls. The presence of flaking, lead-based paint in older (pre-1978) housing is a major public health concern. Children can suffer permanent mental handicaps and psychological disorders if they are subjected to elevated levels of lead, while adults can suffer hypertension and other maladies. Studies have found that, in some urban communities with older housing stocks, over 35% of children tested have elevated blood lead levels (Hastings, et al.: 1997). Nationally, nearly 22% of black, non-hispanic children living in pre-1946 housing were found to have elevated levels of lead in their blood (MWWR Article: February 21,1997). The deterioration of many of these walls is to the point that lead can freely enter the living space.

  2. Modeling and simulation of cascading contingencies

    NASA Astrophysics Data System (ADS)

    Zhang, Jianfeng

    This dissertation proposes a new approach to model and study cascading contingencies in large power systems. The most important contribution of the work involves the development and validation of a heuristic analytic model to assess the likelihood of cascading contingencies, and the development and validation of a uniform search strategy. We model the probability of cascading contingencies as a function of power flow and power flow changes. Utilizing logistic regression, the proposed model is calibrated using real industry data. This dissertation analyzes random search strategies for Monte Carlo simulations and proposes a new uniform search strategy based on the Metropolis-Hastings Algorithm. The proposed search strategy is capable of selecting the most significant cascading contingencies, and it is capable of constructing an unbiased estimator to provide a measure of system security. This dissertation makes it possible to reasonably quantify system security and justify security operations when economic concerns conflict with reliability concerns in the new competitive power market environment. It can also provide guidance to system operators about actions that may be taken to reduce the risk of major system blackouts. Various applications can be developed to take advantage of the quantitative security measures provided in this dissertation.

  3. Projection of mesothelioma mortality in Britain using Bayesian methods

    PubMed Central

    Tan, E; Warren, N; Darnton, A J; Hodgson, J T

    2010-01-01

    Background: Mesothelioma mortality has increased more than ten-fold over the past 40 years in Great Britain, with >1700 male deaths recorded in the British mesothelioma register in 2006. Annual mesothelioma deaths now account for >1% of all cancer deaths. A Poisson regression model based on a previous work by Hodgson et al has been fitted, which has allowed informed statistical inferences about model parameters and predictions of future mesothelioma mortality to be made. Methods: In the Poisson regression model, the mesothelioma risk of an individual depends on the average collective asbestos dose for the individual in a given year and an age-specific exposure potential. The model has been fitted to the data within a Bayesian framework using the Metropolis–Hastings algorithm, a Markov Chain Monte Carlo technique, providing credible intervals for model parameters as well as prediction intervals for the number of future cases of mortality. Results: Males were most likely to have been exposed to asbestos between the ages of 30 and 49 years, with the peak year of asbestos exposure estimated to be 1963. The estimated number of background cases was 1.08 cases per million population. Conclusion: Mortality among males is predicted to peak at approximately 2040 deaths in the year 2016, with a rapid decline thereafter. Approximately 91 000 deaths are predicted to occur from 1968 to 2050 with around 61 000 of these occurring from 2007 onwards. PMID:20628377

  4. Bayesian adaptive Markov chain Monte Carlo estimation of genetic parameters.

    PubMed

    Mathew, B; Bauer, A M; Koistinen, P; Reetz, T C; Léon, J; Sillanpää, M J

    2012-10-01

    Accurate and fast estimation of genetic parameters that underlie quantitative traits using mixed linear models with additive and dominance effects is of great importance in both natural and breeding populations. Here, we propose a new fast adaptive Markov chain Monte Carlo (MCMC) sampling algorithm for the estimation of genetic parameters in the linear mixed model with several random effects. In the learning phase of our algorithm, we use the hybrid Gibbs sampler to learn the covariance structure of the variance components. In the second phase of the algorithm, we use this covariance structure to formulate an effective proposal distribution for a Metropolis-Hastings algorithm, which uses a likelihood function in which the random effects have been integrated out. Compared with the hybrid Gibbs sampler, the new algorithm had better mixing properties and was approximately twice as fast to run. Our new algorithm was able to detect different modes in the posterior distribution. In addition, the posterior mode estimates from the adaptive MCMC method were close to the REML (residual maximum likelihood) estimates. Moreover, our exponential prior for inverse variance components was vague and enabled the estimated mode of the posterior variance to be practically zero, which was in agreement with the support from the likelihood (in the case of no dominance). The method performance is illustrated using simulated data sets with replicates and field data in barley.

  5. Local perturbations perturb—exponentially–locally

    SciTech Connect

    De Roeck, W. Schütz, M.

    2015-06-15

    We elaborate on the principle that for gapped quantum spin systems with local interaction, “local perturbations [in the Hamiltonian] perturb locally [the groundstate].” This principle was established by Bachmann et al. [Commun. Math. Phys. 309, 835–871 (2012)], relying on the “spectral flow technique” or “quasi-adiabatic continuation” [M. B. Hastings, Phys. Rev. B 69, 104431 (2004)] to obtain locality estimates with sub-exponential decay in the distance to the spatial support of the perturbation. We use ideas of Hamza et al. [J. Math. Phys. 50, 095213 (2009)] to obtain similarly a transformation between gapped eigenvectors and their perturbations that is local with exponential decay. This allows to improve locality bounds on the effect of perturbations on the low lying states in certain gapped models with a unique “bulk ground state” or “topological quantum order.” We also give some estimate on the exponential decay of correlations in models with impurities where some relevant correlations decay faster than one would naively infer from the global gap of the system, as one also expects in disordered systems with a localized groundstate.

  6. MRI micturating urethrography for improved urethral delineation in prostate radiotherapy planning: a case study

    NASA Astrophysics Data System (ADS)

    Rai, Robba; Sidhom, Mark; Lim, Karen; Ohanessian, Lucy; Liney, Gary P.

    2017-04-01

    Stereotactic ablative body radiotherapy is used in prostate cancer to deliver a high dose of radiation to the tumour over a small number of treatments. This involves the simulation of the patient using both CT and MRI. Current practice is to insert an indwelling catheter (IDC) during CT to assist with visualisation of the urethra and subsequently minimise dose to this highly critical structure. However, this procedure is invasive and has an associated risk of infection. This is a case study, which demonstrates our initial experience of using a real-time non-invasive MRI technique to replace the use of IDC for prostate cancer patients. The patient was scanned on a dedicated 3T MRI and was instructed to micturate in their own time whereupon a sagittal T2 weighted HASTE sequence was acquired every 5 s. This was subsequently followed by T2 weighted axial imaging at the level of mid prostate to provide improved urethral definition. Acquired images showed bladder voidance in real-time and an increase in signal intensity in the proximal urethra post voiding allowing for delineation of the urethra. The dimension and shape of the proximal urethra was well visualised and accumulation time of urine in the urethra was sufficient to enable optimum timing of the scanning technique. We have presented for the first time a micturating urethography technique using MRI, which has allowed us to visualise the urethra without contrast and with minimal invasiveness to the patient.

  7. Ascertainment correction for Markov chain Monte Carlo segregation and linkage analysis of a quantitative trait.

    PubMed

    Ma, Jianzhong; Amos, Christopher I; Warwick Daw, E

    2007-09-01

    Although extended pedigrees are often sampled through probands with extreme levels of a quantitative trait, Markov chain Monte Carlo (MCMC) methods for segregation and linkage analysis have not been able to perform ascertainment corrections. Further, the extent to which ascertainment of pedigrees leads to biases in the estimation of segregation and linkage parameters has not been previously studied for MCMC procedures. In this paper, we studied these issues with a Bayesian MCMC approach for joint segregation and linkage analysis, as implemented in the package Loki. We first simulated pedigrees ascertained through individuals with extreme values of a quantitative trait in spirit of the sequential sampling theory of Cannings and Thompson [Cannings and Thompson [1977] Clin. Genet. 12:208-212]. Using our simulated data, we detected no bias in estimates of the trait locus location. However, in addition to allele frequencies, when the ascertainment threshold was higher than or close to the true value of the highest genotypic mean, bias was also found in the estimation of this parameter. When there were multiple trait loci, this bias destroyed the additivity of the effects of the trait loci, and caused biases in the estimation all genotypic means when a purely additive model was used for analyzing the data. To account for pedigree ascertainment with sequential sampling, we developed a Bayesian ascertainment approach and implemented Metropolis-Hastings updates in the MCMC samplers used in Loki. Ascertainment correction greatly reduced biases in parameter estimates. Our method is designed for multiple, but a fixed number of trait loci.

  8. A consideration of the operation of automatic production machines

    PubMed Central

    HOSHI, Toshiro; SUGIMOTO, Noboru

    2015-01-01

    At worksites, various automatic production machines are in use to release workers from muscular labor or labor in the detrimental environment. On the other hand, a large number of industrial accidents have been caused by automatic production machines. In view of this, this paper considers the operation of automatic production machines from the viewpoint of accident prevention, and points out two types of machine operation − operation for which quick performance is required (operation that is not permitted to be delayed) − and operation for which composed performance is required (operation that is not permitted to be performed in haste). These operations are distinguished by operation buttons of suitable colors and shapes. This paper shows that these characteristics are evaluated as “asymmetric on the time-axis”. Here, in order for workers to accept the risk of automatic production machines, it is preconditioned in general that harm should be sufficiently small or avoidance of harm is easy. In this connection, this paper shows the possibility of facilitating the acceptance of the risk of automatic production machines by enhancing the asymmetric on the time-axis. PMID:25739898

  9. Automatic Iceball Segmentation With Adapted Shape Priors for MRI-Guided Cryoablation

    PubMed Central

    Liu, Xinyang; Tuncali, Kemal; Wells, William M.; Zientara, Gary P.

    2014-01-01

    Purpose To develop and evaluate an automatic segmentation method that extracts the 3D configuration of the ablation zone, the iceball, from images acquired during the freezing phase of MRI-guided cryoablation. Materials and Methods Intraprocedural images at 63 timepoints from 13 kidney tumor cryoablation procedures were examined retrospectively. The images were obtained using a 3 Tesla wide-bore MRI scanner and axial HASTE sequence. Initialized with semiautomatically localized cryoprobes, the iceball was segmented automatically at each timepoint using the graph cut (GC) technique with adapted shape priors. Results The average Dice Similarity Coefficients (DSC), compared with manual segmentations, were 0.88, 0.92, 0.92, 0.93, and 0.93 at 3, 6, 9, 12, and 15 min time-points, respectively, and the average DSC of the total 63 segmentations was 0.92 ± 0.03. The proposed method improved the accuracy significantly compared with the approach without shape prior adaptation (P = 0.026). The number of probes involved in the procedure had no apparent influence on the segmentation results using our technique. The average computation time was 20 s, which was compatible with an intraprocedural setting. Conclusion Our automatic iceball segmentation method demonstrated high accuracy and robustness for practical use in monitoring the progress of MRI-guided cryoablation. PMID:24338961

  10. Exploring equivalence domain in nonlinear inverse problems using Covariance Matrix Adaption Evolution Strategy (CMAES) and random sampling

    NASA Astrophysics Data System (ADS)

    Grayver, Alexander V.; Kuvshinov, Alexey V.

    2016-05-01

    This paper presents a methodology to sample equivalence domain (ED) in nonlinear partial differential equation (PDE)-constrained inverse problems. For this purpose, we first applied state-of-the-art stochastic optimization algorithm called Covariance Matrix Adaptation Evolution Strategy (CMAES) to identify low-misfit regions of the model space. These regions were then randomly sampled to create an ensemble of equivalent models and quantify uncertainty. CMAES is aimed at exploring model space globally and is robust on very ill-conditioned problems. We show that the number of iterations required to converge grows at a moderate rate with respect to number of unknowns and the algorithm is embarrassingly parallel. We formulated the problem by using the generalized Gaussian distribution. This enabled us to seamlessly use arbitrary norms for residual and regularization terms. We show that various regularization norms facilitate studying different classes of equivalent solutions. We further show how performance of the standard Metropolis-Hastings Markov chain Monte Carlo algorithm can be substantially improved by using information CMAES provides. This methodology was tested by using individual and joint inversions of magneotelluric, controlled-source electromagnetic (EM) and global EM induction data.

  11. Assessment of burden of virus agents in an urban sewage treatment plant in Rio de Janeiro, Brazil.

    PubMed

    Fumian, Tulio Machado; Vieira, Carmen Baur; Leite, José Paulo Gagliardi; Miagostovich, Marize Pereira

    2013-03-01

    Sewage discharge is considered to be the main source of virus contamination in aquatic environments. There is no correlation between the presence of viruses and the presence of fecal coliforms in water; therefore virological markers are needed when monitoring contamination. This study investigates DNA and RNA virus concentrations in wastewater and evaluates a potential virus marker of human contamination. Influent and effluent samples were collected twice a month throughout a 1-year period. Viruses were detected using quantitative polymerase chain reaction protocols; nucleotide sequencing was carried out for virus genotyping. Human adenovirus (HAdV) and polyomavirus JC (JCPyV) were the most prevalent viruses found in influent samples (100%) with a virus load that ranged from 10(6) to 10(5) genome copies per liter (gc l(-1)). Norovirus genogroup II (NoV GII) and human astrovirus (HAstV) were less prevalent, and ranged from 10(4) to 10(3)gc l(-1). Quantitative data on virus profiles in wastewaters stress the high level of rotavirus species A environmental dissemination and address the potential of HAdV as a useful virological marker of virus contamination in aquatic environments. This study corroborates other studies performed in developed countries on DNA viruses as good markers of human fecal contamination.

  12. HZAR: hybrid zone analysis using an R software package.

    PubMed

    Derryberry, Elizabeth P; Derryberry, Graham E; Maley, James M; Brumfield, Robb T

    2014-05-01

    We present a new software package (HZAR) that provides functions for fitting molecular genetic and morphological data from hybrid zones to classic equilibrium cline models using the Metropolis-Hastings Markov chain Monte Carlo (MCMC) algorithm. The software applies likelihood functions appropriate for different types of data, including diploid and haploid genetic markers and quantitative morphological traits. The modular design allows flexibility in fitting cline models of varying complexity. To facilitate hypothesis testing, an autofit function is included that allows automated model selection from a set of nested cline models. Cline parameter values, such as cline centre and cline width, are estimated and may be compared statistically across clines. The package is written in the R language and is available through the Comprehensive R Archive Network (CRAN; http://cran.r-project.org/). Here, we describe HZAR and demonstrate its use with a sample data set from a well-studied hybrid zone in western Panama between white-collared (Manacus candei) and golden-collared manakins (M. vitellinus). Comparisons of our results with previously published results for this hybrid zone validate the hzar software. We extend analysis of this hybrid zone by fitting additional models to molecular data where appropriate.

  13. Variational method for estimating the rate of convergence of Markov-chain Monte Carlo algorithms.

    PubMed

    Casey, Fergal P; Waterfall, Joshua J; Gutenkunst, Ryan N; Myers, Christopher R; Sethna, James P

    2008-10-01

    We demonstrate the use of a variational method to determine a quantitative lower bound on the rate of convergence of Markov chain Monte Carlo (MCMC) algorithms as a function of the target density and proposal density. The bound relies on approximating the second largest eigenvalue in the spectrum of the MCMC operator using a variational principle and the approach is applicable to problems with continuous state spaces. We apply the method to one dimensional examples with Gaussian and quartic target densities, and we contrast the performance of the random walk Metropolis-Hastings algorithm with a "smart" variant that incorporates gradient information into the trial moves, a generalization of the Metropolis adjusted Langevin algorithm. We find that the variational method agrees quite closely with numerical simulations. We also see that the smart MCMC algorithm often fails to converge geometrically in the tails of the target density except in the simplest case we examine, and even then care must be taken to choose the appropriate scaling of the deterministic and random parts of the proposed moves. Again, this calls into question the utility of smart MCMC in more complex problems. Finally, we apply the same method to approximate the rate of convergence in multidimensional Gaussian problems with and without importance sampling. There we demonstrate the necessity of importance sampling for target densities which depend on variables with a wide range of scales.

  14. Earth's core and inner-core resonances from analysis of VLBI nutation and superconducting gravimeter data

    NASA Astrophysics Data System (ADS)

    Rosat, S.; Lambert, S. B.; Gattano, C.; Calvo, M.

    2017-01-01

    Geophysical parameters of the deep Earth's interior can be evaluated through the resonance effects associated with the core and inner-core wobbles on the forced nutations of the Earth's figure axis, as observed by very long baseline interferometry (VLBI), or on the diurnal tidal waves, retrieved from the time-varying surface gravity recorded by superconducting gravimeters (SGs). In this paper, we inverse for the rotational mode parameters from both techniques to retrieve geophysical parameters of the deep Earth. We analyse surface gravity data from 15 SG stations and VLBI delays accumulated over the last 35 yr. We show existing correlations between several basic Earth parameters and then decide to inverse for the rotational modes parameters. We employ a Bayesian inversion based on the Metropolis-Hastings algorithm with a Markov-chain Monte Carlo method. We obtain estimates of the free core nutation resonant period and quality factor that are consistent for both techniques. We also attempt an inversion for the free inner-core nutation (FICN) resonant period from gravity data. The most probable solution gives a period close to the annual prograde term (or S1 tide). However the 95 per cent confidence interval extends the possible values between roughly 28 and 725 d for gravity, and from 362 to 414 d from nutation data, depending on the prior bounds. The precisions of the estimated long-period nutation and respective small diurnal tidal constituents are hence not accurate enough for a correct determination of the FICN complex frequency.

  15. Earth's core and inner core resonances from analysis of VLBI nutation and superconducting gravimeter data

    NASA Astrophysics Data System (ADS)

    Rosat, S.; Lambert, S. B.; Gattano, C.; Calvo, M.

    2016-10-01

    Geophysical parameters of the deep Earth's interior can be evaluated through the resonance effects associated with the core and inner-core wobbles on the forced nutations of the Earth's figure axis, as observed by very long baseline interferometry (VLBI), or on the diurnal tidal waves, retrieved from the time-varying surface gravity recorded by superconducting gravimeters (SGs). In this paper, we inverse for the rotational mode parameters from both techniques to retrieve geophysical parameters of the deep Earth. We analyze surface gravity data from 15 SG stations and VLBI delays accumulated over the last 35 years. We show existing correlations between several basic Earth parameters and then decide to inverse for the rotational modes parameters. We employ a Bayesian inversion based on the Metropolis-Hastings algorithm with a Markov Chain Monte Carlo method. We obtain estimates of the free core nutation (FCN) resonant period and quality factor that are consistent for both techniques. We also attempt an inversion for the free inner core nutation (FICN) resonant period from gravity data. The most probable solution gives a period close to the annual prograde term (or S1 tide). However the 95% confidence interval extend the possible values between roughly 28 days and 725 days for gravity, and from 362 to 414 days from nutation data, depending on the prior bounds. The precisions of the estimated long-period nutation and respective small diurnal tidal constituents are hence not accurate enough for a correct determination of the FICN complex frequency.

  16. Exact sampling of the unobserved covariates in Bayesian spline models for measurement error problems.

    PubMed

    Bhadra, Anindya; Carroll, Raymond J

    2016-07-01

    In truncated polynomial spline or B-spline models where the covariates are measured with error, a fully Bayesian approach to model fitting requires the covariates and model parameters to be sampled at every Markov chain Monte Carlo iteration. Sampling the unobserved covariates poses a major computational problem and usually Gibbs sampling is not possible. This forces the practitioner to use a Metropolis-Hastings step which might suffer from unacceptable performance due to poor mixing and might require careful tuning. In this article we show for the cases of truncated polynomial spline or B-spline models of degree equal to one, the complete conditional distribution of the covariates measured with error is available explicitly as a mixture of double-truncated normals, thereby enabling a Gibbs sampling scheme. We demonstrate via a simulation study that our technique performs favorably in terms of computational efficiency and statistical performance. Our results indicate up to 62 and 54 % increase in mean integrated squared error efficiency when compared to existing alternatives while using truncated polynomial splines and B-splines respectively. Furthermore, there is evidence that the gain in efficiency increases with the measurement error variance, indicating the proposed method is a particularly valuable tool for challenging applications that present high measurement error. We conclude with a demonstration on a nutritional epidemiology data set from the NIH-AARP study and by pointing out some possible extensions of the current work.

  17. An Empirical Prior Improves Accuracy for Bayesian Estimation of Transcription Factor Binding Site Frequencies within Gene Promoters

    PubMed Central

    Ramsey, Stephen A.

    2015-01-01

    A Bayesian method for sampling from the distribution of matches to a precompiled transcription factor binding site (TFBS) sequence pattern (conditioned on an observed nucleotide sequence and the sequence pattern) is described. The method takes a position frequency matrix as input for a set of representative binding sites for a transcription factor and two sets of noncoding, 5′ regulatory sequences for gene sets that are to be compared. An empirical prior on the frequency A (per base pair of gene-vicinal, noncoding DNA) of TFBSs is developed using data from the ENCODE project and incorporated into the method. In addition, a probabilistic model for binding site occurrences conditioned on λ is developed analytically, taking into account the finite-width effects of binding sites. The count of TFBS β (conditioned on the observed sequence) is sampled using Metropolis–Hastings with an information entropy-based move generator. The derivation of the method is presented in a step-by-step fashion, starting from specific conditional independence assumptions. Empirical results show that the newly proposed prior on β improves accuracy for estimating the number of TFBS within a set of promoter sequences. PMID:27812284

  18. A study on operation efficiency evaluation based on firm's financial index and benchmark selection: take China Unicom as an example

    NASA Astrophysics Data System (ADS)

    Wu, Zu-guang; Tian, Zhan-jun; Liu, Hui; Huang, Rui; Zhu, Guo-hua

    2009-07-01

    Being the only listed telecom operators of A share market, China Unicom has always been attracted many institutional investors under the concept of 3G recent years,which itself is a great technical progress expectation.Do the institutional investors or the concept of technical progress have signficant effect on the improving of firm's operating efficiency?Though reviewing the documentary about operating efficiency we find that schoolars study this problem useing the regress analyzing based on traditional production function and data envelopment analysis(DEA) and financial index anayzing and marginal function and capital labor ratio coefficient etc. All the methods mainly based on macrodata. This paper we use the micro-data of company to evaluate the operating efficiency.Using factor analyzing based on financial index and comparing the factor score of three years from 2005 to 2007, we find that China Unicom's operating efficiency is under the averge level of benchmark corporates and has't improved under the concept of 3G from 2005 to 2007.In other words,institutional investor or the conception of technical progress expectation have faint effect on the changes of China Unicom's operating efficiency. Selecting benchmark corporates as post to evaluate the operating efficiency is a characteristic of this method ,which is basicallly sipmly and direct.This method is suit for the operation efficiency evaluation of agriculture listed companies because agriculture listed also face technical progress and marketing concept such as tax-free etc.

  19. Altering risky decision-making: Influence of impulsivity on the neuromodulation of prefrontal cortex.

    PubMed

    Cheng, Gordon L F; Lee, Tatia M C

    2016-01-01

    The prefrontal cortex (PFC) subserves complex cognitive abilities, including risky decision-making; the modulation of this brain area is shown to alter the way people take risks. Yet, neuromodulation of the PFC in relation to risk-taking behavior remains relatively less well-studied. Moreover, the psychological variables that influence such neuromodulation remain poorly understood. To address these issues, 16 participants took part in 3 experimental sessions on separate days. They received: (i) left anodal-right cathodal transcranial direct current stimulation (tDCS); (ii) left cathodal-right anodal stimulation; or (iii) sham stimulation while they completed two risk-taking tasks. They also measured on several cognitive-affective abilities and personality traits. It was revealed that left cathodal-right anodal stimulation led to significantly reduced risk-taking under a context of haste. The reduction of risk-taking (relative to sham) correlated with state and trait impulsivity, such that the effect was larger in more impulsive individuals. For these individuals, the tDCS effect size was considered to be large (generalized partial η(2) > .17). The effect of prefrontal-neuromodulation in reducing risk-taking was influenced by baseline impulsivity, reflecting a state-dependent effect of neuromodulation on the PFC. The results of this study carry important insights into the use of neuromodulation to alter higher cognition.

  20. Primary charge separation in isolated photosystem II reaction centers

    SciTech Connect

    Seibert, M.; Toon, S.; Govindjee; O`Neil, M.P.; Wasielewski, M.R.

    1992-08-24

    Primary charge-separation in isolated bacterial reaction center (RC) complex occurs in 2.8 ps at room temperature and 0.7--1.2 ps at 10 K. Because of similarities between the bacterial and photosystem II (PSII) RCs, it has been of considerable interest to obtain analogous charge-separation rates in the higher plant system. Our previous femtosecond transient absorption studies used PSII RC material stabilized with PEG or by exchanging dodecyl maltoside (DM) for Triton in the isolation procedure. These materials gave charge-separation 1/e times of 3.0 {plus_minus} 0.6 ps at 4{degree}C and 1.4{plus_minus} 0.2 ps at 15 K based on the risetime of transient absorption kinetics at 820 nm. These values were thought to represent the time required for formation of the P680{sup +}-Pheo{sup {minus}} state. Recent results of Hastings et al. obtained at high data acquisition rates and low flash intensities, suggest that the Pheo{sup {minus}} state may form more slowly. In light of this work, we have carried out additional time domain studies of both electron transport and energy transfer phenomena in stabilized DM PSII RCs at room temperature. We used a 1-kHz repetition rate femtosecond transient absorption spectrometer with a 200 fs instrumental time resolution and compared the results with those obtained by others using frequency domain hole-burning techniques.

  1. Permanence in an intraguild predation model with prey switching.

    PubMed

    Zabalo, Joaquin

    2012-09-01

    Intraguild predation, a form of omnivory that can occur in simple food webs when one species preys on and competes for limiting resources with another species, can have either a stabilizing effect (McCann and Hastings in Proc. R. Soc. Lond. B 264:1249-1254, 1997) or a destabilizing effect (Holt and Polis in Am. Nat. 149:745-764, 1997), depending on the assumptions of the system. Another type of behavior that has been observed in simple food web experiments (Murdoch in Ecol. Monogr. 39:335-354, 1969) is prey switching. Prey switching can occur when the predator prefers the most abundant prey. This has also been shown to be capable of having either a stabilizing effect or a destabilizing effect and even possibly lead to predator extinction (VanLeeuwen et al. in Ecology 88:1571-1581, 2007). Therefore, it is clear that incorporating prey switching into an intraguild predation model could lead to unexpected consequences. In this paper, we propose and explore such a model.

  2. A coupled hidden Markov model for disease interactions

    PubMed Central

    Sherlock, Chris; Xifara, Tatiana; Telfer, Sandra; Begon, Mike

    2013-01-01

    To investigate interactions between parasite species in a host, a population of field voles was studied longitudinally, with presence or absence of six different parasites measured repeatedly. Although trapping sessions were regular, a different set of voles was caught at each session, leading to incomplete profiles for all subjects. We use a discrete time hidden Markov model for each disease with transition probabilities dependent on covariates via a set of logistic regressions. For each disease the hidden states for each of the other diseases at a given time point form part of the covariate set for the Markov transition probabilities from that time point. This allows us to gauge the influence of each parasite species on the transition probabilities for each of the other parasite species. Inference is performed via a Gibbs sampler, which cycles through each of the diseases, first using an adaptive Metropolis–Hastings step to sample from the conditional posterior of the covariate parameters for that particular disease given the hidden states for all other diseases and then sampling from the hidden states for that disease given the parameters. We find evidence for interactions between several pairs of parasites and of an acquired immune response for two of the parasites. PMID:24223436

  3. A coupled hidden Markov model for disease interactions.

    PubMed

    Sherlock, Chris; Xifara, Tatiana; Telfer, Sandra; Begon, Mike

    2013-08-01

    To investigate interactions between parasite species in a host, a population of field voles was studied longitudinally, with presence or absence of six different parasites measured repeatedly. Although trapping sessions were regular, a different set of voles was caught at each session, leading to incomplete profiles for all subjects. We use a discrete time hidden Markov model for each disease with transition probabilities dependent on covariates via a set of logistic regressions. For each disease the hidden states for each of the other diseases at a given time point form part of the covariate set for the Markov transition probabilities from that time point. This allows us to gauge the influence of each parasite species on the transition probabilities for each of the other parasite species. Inference is performed via a Gibbs sampler, which cycles through each of the diseases, first using an adaptive Metropolis-Hastings step to sample from the conditional posterior of the covariate parameters for that particular disease given the hidden states for all other diseases and then sampling from the hidden states for that disease given the parameters. We find evidence for interactions between several pairs of parasites and of an acquired immune response for two of the parasites.

  4. An attraction-repulsion point process model for respiratory syncytial virus infections.

    PubMed

    Goldstein, Joshua; Haran, Murali; Simeonov, Ivan; Fricks, John; Chiaromonte, Francesca

    2015-06-01

    How is the progression of a virus influenced by properties intrinsic to individual cells? We address this question by studying the susceptibility of cells infected with two strains of the human respiratory syncytial virus (RSV-A and RSV-B) in an in vitro experiment. Spatial patterns of infected cells give us insight into how local conditions influence susceptibility to the virus. We observe a complicated attraction and repulsion behavior, a tendency for infected cells to lump together or remain apart. We develop a new spatial point process model to describe this behavior. Inference on spatial point processes is difficult because the likelihood functions of these models contain intractable normalizing constants; we adapt an MCMC algorithm called double Metropolis-Hastings to overcome this computational challenge. Our methods are computationally efficient even for large point patterns consisting of over 10,000 points. We illustrate the application of our model and inferential approach to simulated data examples and fit our model to various RSV experiments. Because our model parameters are easy to interpret, we are able to draw meaningful scientific conclusions from the fitted models.

  5. GRID-BASED EXPLORATION OF COSMOLOGICAL PARAMETER SPACE WITH SNAKE

    SciTech Connect

    Mikkelsen, K.; Næss, S. K.; Eriksen, H. K.

    2013-11-10

    We present a fully parallelized grid-based parameter estimation algorithm for investigating multidimensional likelihoods called Snake, and apply it to cosmological parameter estimation. The basic idea is to map out the likelihood grid-cell by grid-cell according to decreasing likelihood, and stop when a certain threshold has been reached. This approach improves vastly on the 'curse of dimensionality' problem plaguing standard grid-based parameter estimation simply by disregarding grid cells with negligible likelihood. The main advantages of this method compared to standard Metropolis-Hastings Markov Chain Monte Carlo methods include (1) trivial extraction of arbitrary conditional distributions; (2) direct access to Bayesian evidences; (3) better sampling of the tails of the distribution; and (4) nearly perfect parallelization scaling. The main disadvantage is, as in the case of brute-force grid-based evaluation, a dependency on the number of parameters, N{sub par}. One of the main goals of the present paper is to determine how large N{sub par} can be, while still maintaining reasonable computational efficiency; we find that N{sub par} = 12 is well within the capabilities of the method. The performance of the code is tested by comparing cosmological parameters estimated using Snake and the WMAP-7 data with those obtained using CosmoMC, the current standard code in the field. We find fully consistent results, with similar computational expenses, but shorter wall time due to the perfect parallelization scheme.

  6. The Full Monte Carlo: A Live Performance with Stars

    NASA Astrophysics Data System (ADS)

    Meng, Xiao-Li

    2014-06-01

    Markov chain Monte Carlo (MCMC) is being applied increasingly often in modern Astrostatistics. It is indeed incredibly powerful, but also very dangerous. It is popular because of its apparent generality (from simple to highly complex problems) and simplicity (the availability of out-of-the-box recipes). It is dangerous because it always produces something but there is no surefire way to verify or even diagnosis that the “something” is remotely close to what the MCMC theory predicts or one hopes. Using very simple models (e.g., conditionally Gaussian), this talk starts with a tutorial of the two most popular MCMC algorithms, namely, the Gibbs Sampler and the Metropolis-Hasting Algorithm, and illustratestheir good, bad, and ugly implementations via live demonstration. The talk ends with a story of how a recent advance, the Ancillary-Sufficient Interweaving Strategy (ASIS) (Yu and Meng, 2011, http://www.stat.harvard.edu/Faculty_Content/meng/jcgs.2011-article.pdf)reduces the danger. It was discovered almost by accident during a Ph.D. student’s (Yaming Yu) struggle with fitting a Cox process model for detecting changes in source intensity of photon counts observed by the Chandra X-ray telescope from a (candidate) neutron/quark star.

  7. Chemical analyses of surface waters in Oklahoma, September - December, 1944

    USGS Publications Warehouse

    ,

    1945-01-01

    Red River at Denison Dam, Texas Sport samples were collected at the remainder of the stations. The analyses of the spot samples were made largely in a laboratory provided by the Oklahoma A. & M. College, under the supervision of Dr. O.M. Smith, Head, Department of Chemistry; Dr. S.R. Wood, Associate Professor of Chemistry; and W.W. Hastings, U.S. Geological Survey. The daily samples were analyzed in the water resources laboratory of the Geological Survey at Austin, Texas. These data have been summarized in a report to the Oklahoma Planning and Resources Board prepared by the U.S. Geological Survey, March 1, 1945. The streams of Oklahoma are classified into two major drainage basins: the Arkansas River and the Red River and their tributaries. The attached analyses are arranged in geographical order for their respective drainage basins, with records listed in downstream order for stations on the main stem first, followed by the analyses for the tributaries. When available, the mean daily discharge is given for the analyses.

  8. Probabilistic two-dimensional water-column and seabed inversion with self-adapting parameterizations.

    PubMed

    Dettmer, Jan; Dosso, Stan E

    2013-05-01

    This paper develops a probabilistic two-dimensional (2D) inversion for geoacoustic seabed and water-column parameters in a strongly range-dependent environment. Range-dependent environments in shelf and shelf-break regions are of increasing importance to the acoustical-oceanography community, and recent advances in nonlinear inverse theory and sampling methods are applied here for efficient probabilistic range-dependent inversion. The 2D seabed and water column are parameterized using highly efficient, self-adapting irregular grids which intrinsically match the local resolving power of the data and provide parsimonious solutions requiring few parameters to capture complex environments. The self-adapting parameterization is achieved by implementing the irregular grid as a trans-dimensional hierarchical Bayesian model with an unknown number of nodes which is sampled with the Metropolis-Hastings-Green algorithm. To improve sampling, population Monte Carlo is applied with a large number of interacting parallel Markov chains with adaptive proposal distributions. The inversion is applied to simulated data for a vertical-line array and several source locations to several kilometers range. Complex acoustic-pressure fields are computed using a parabolic equation model and results are considered in terms of 2D ensemble parameter estimates and credibility intervals.

  9. MR enteroclysis imaging of Crohn disease.

    PubMed

    Prassopoulos, P; Papanikolaou, N; Grammatikakis, J; Rousomoustakaki, M; Maris, T; Gourtsoyiannis, N

    2001-10-01

    Magnetic resonance (MR) enteroclysis imaging is emerging as a technique for evaluation of the small bowel in patients with Crohn disease. Administration of 1.5-2 L of isosmotic water solution through a nasojejunal catheter ensures distention of the bowel and facilitates identification of wall abnormalities. True fast imaging with steady-state precession (FISP), half-Fourier acquisition single-shot turbo spin-echo (HASTE), and postgadolinium T1-weighted three-dimensional fast low-angle shot sequences can be employed in a comprehensive and integrated MR enteroclysis examination protocol to overcome specific disadvantages of each of the sequences involved. Superficial abnormalities that are ideally delineated with conventional enteroclysis are not consistently depicted with MR enteroclysis. The characteristic transmural abnormalities of Crohn disease such as bowel wall thickening, linear ulcers, and cobblestoning are accurately shown with MR enteroclysis imaging, especially with the true FISP sequence. MR enteroclysis is comparable to conventional enteroclysis in the detection of the number and extent of involved small bowel segments and in the disclosure of luminal narrowing or prestenotic intestinal dilatation. The clinical utility of MR enteroclysis in Crohn disease has not been fully established. At present, the method may be used for follow-up studies of known disease, estimation of disease activity, and determination of the extramucosal extent and spread of the disease process.

  10. Documenting citizenship in Medicaid: the struggle between ideology and evidence.

    PubMed

    Ku, Leighton; Pervez, Fouad

    2010-02-01

    In 2006 Congress passed, and the Centers for Medicare and Medicaid Services (CMS) rapidly issued, regulations requiring states to obtain proof of citizenship from citizens who had applied for Medicaid. This policy was framed as reducing fraud by illegal aliens to preserve benefits for citizens. In fact, evidence indicates there was no significant problem of fraud by immigrants, and the major effect of the policy was to reduce coverage of eligible citizens. This article addresses the reasons why Congress developed this policy and why CMS acted with uncharacteristic haste to implement these counterproductive policies. We note the importance of the policy's symbolic framing--that is, as establishing sanctions against illegal immigration--in congressional passage during a period of rising nativism in Congress and the nation. The regulatory actions reflected the ideological preferences of political appointees and an increasingly adversarial relationship between CMS and state agencies during this period. These haphazard regulatory actions made the policies more convoluted and likely led more eligible citizens to lose coverage. In 2009, Congress amended the law to modify implementation. These issues have continued to persist in the recent debate on national health care reform.

  11. Imaging the propagation of shock waves with both high temporal and high spatial resolution using XFELs

    NASA Astrophysics Data System (ADS)

    Schropp, Andreas

    2013-06-01

    The emergence of x-ray sources of the fourth generation, so called x-ray free-electron lasers (XFELs), comes along with completely new research opportunities in various scientific fields. During the last year we developed an x-ray microscope based on beryllium compound refractive lenses (Be-CRLs), which is especially optimized for the XFEL environment and provides focusing capabilities down to 100nm and even below. Based on magnified x-ray phase contrast imaging, this new setup enables us to pursue high-resolution x-ray imaging experiments with single XFEL-pulses. In a first experiment, carried out at the Matter in Extreme Conditions (MEC) endstation of the LCLS, the performance of the instrument was investigated by direct imaging of shock waves in different materials. The shock wave was induced by an intense 150 ps optical laser pulse. The evolution of the shock wave was then monitored with the XFEL-beam. In this contribution we report on first analysis results of phase contrast imaging of shock waves in matter. In collaboration with Brice Arnold, Eric Galtier, Hae Ja Lee, Bob Nagler, Jerome Hastings, SLAC National Accelerator Laboratory, 2575 Sand Hill Rd., Menlo Park, CA 94025, USA; Damian Hicks, Yuan Ping, Gilbert Collins, Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, CA 94551, USA; and Robert Hoppe, Vivienne Meier, Jens Patommel, Frank Seiboth, Christian Schroer, Institute of Structural Physics, Technische Universität Dresden, D-01062 Dresden, Germany.

  12. Geothermal Energy Production from Oil/Gas Wells and Application for Building Cooling

    SciTech Connect

    Wang, Honggang; Liu, Xiaobing

    2016-01-01

    One significant source of low-temperature geothermal energy is the coproduced hot water from oil/gas field production. In the United States, daily oil production has reached above 8 million barrels in recent years. Considering various conditions of wells, 5-10 times or more water can be coproduced in the range of temperature 120 F to 300 F. Like other geothermal resources, such energy source from oil/gas wells is under-utilized for its typical long distance from consumption sites. Many oil/gas fields, however, are relatively close (less than 10 miles) to consumers around cities. For instance, some petroleum fields in Pennsylvania are only a few miles away from the towns in Pittsburg area and some fields in Texas are quite close to Houston. In this paper, we evaluate geothermal potential from oil/gas wells by conducting numerical simulation and analysis of a fractured oil well in Hastings West field, Texas. The results suggest that hot water can be continuously coproduced from oil wells at a sufficient rate (about 4000 gallons/day from one well) for more than 100 years. Viable use of such geothermal source requires economical transportation of energy to consumers. The recently proposed two-step geothermal absorption (TSGA) system provides a promising energy transport technology that allows large-scale use of geothermal energy from thousands of oil/gas wells.

  13. Distinct mechanisms mediate speed-accuracy adjustments in cortico-subthalamic networks

    PubMed Central

    Herz, Damian M; Tan, Huiling; Brittain, John-Stuart; Fischer, Petra; Cheeran, Binith; Green, Alexander L; FitzGerald, James; Aziz, Tipu Z; Ashkan, Keyoumars; Little, Simon; Foltynie, Thomas; Limousin, Patricia; Zrinzo, Ludvic; Bogacz, Rafal; Brown, Peter

    2017-01-01

    Optimal decision-making requires balancing fast but error-prone and more accurate but slower decisions through adjustments of decision thresholds. Here, we demonstrate two distinct correlates of such speed-accuracy adjustments by recording subthalamic nucleus (STN) activity and electroencephalography in 11 Parkinson’s disease patients during a perceptual decision-making task; STN low-frequency oscillatory (LFO) activity (2–8 Hz), coupled to activity at prefrontal electrode Fz, and STN beta activity (13–30 Hz) coupled to electrodes C3/C4 close to motor cortex. These two correlates differed not only in their cortical topography and spectral characteristics but also in the relative timing of recruitment and in their precise relationship with decision thresholds. Increases of STN LFO power preceding the response predicted increased thresholds only after accuracy instructions, while cue-induced reductions of STN beta power decreased thresholds irrespective of instructions. These findings indicate that distinct neural mechanisms determine whether a decision will be made in haste or with caution. DOI: http://dx.doi.org/10.7554/eLife.21481.001 PMID:28137358

  14. Quantum Spin Liquids and Fractionalization

    NASA Astrophysics Data System (ADS)

    Misguich, Grégoire

    This chapter discusses quantum antiferromagnets which do not break any symmetries at zero temperature - also called "spin liquids" - and focuses on lattice spin models with Heisenberg-like (i.e. SU(2)-symmetric) interactions in dimensions larger than one. We begin by discussing the Lieb-Schultz-Mattis theorem and its recent extension to D > 1 by Hastings (2004), which establishes an important distinction between spin liquids with an integer and with a half-integer spin per unit cell. Spin liquids of the first kind, "band insulators", can often be understood by elementary means, whereas the latter, "Mott insulators", are more complex (featuring "topological order") and support spin-1/2 excitations (spinons). The fermionic formalism (Affleck and Marston, 1988) is described and the effect of fluctuations about mean-field solutions, such as the possible creation of instabilities, is discussed in a qualitative way. In particular, we explain the emergence of gauge modes and their relation to fractionalization. The concept of the projective symmetry group (X.-G. Wen, 2002) is introduced, with the aid of some examples. Finally, we present the phenomenology of (gapped) short-ranged resonating-valence-bond spin liquids, and make contact with the fermionic approach by discussing their description in terms of a fluctuating Z 2 gauge field. Some recent references are given to other types of spin liquid, including gapless ones.

  15. Staphylococcus aureus Develops an Alternative, ica-Independent Biofilm in the Absence of the arlRS Two-Component System†

    PubMed Central

    Toledo-Arana, Alejandro; Merino, Nekane; Vergara-Irigaray, Marta; Débarbouillé, Michel; Penadés, José R.; Lasa, Iñigo

    2005-01-01

    The biofilm formation capacity of Staphylococcus aureus clinical isolates is considered an important virulence factor for the establishment of chronic infections. Environmental conditions affect the biofilm formation capacity of S. aureus, indicating the existence of positive and negative regulators of the process. The majority of the screening procedures for identifying genes involved in biofilm development have been focused on genes whose presence is essential for the process. In this report, we have used random transposon mutagenesis and systematic disruption of all S. aureus two-component systems to identify negative regulators of S. aureus biofilm development in a chemically defined medium (Hussain-Hastings-White modified medium [HHWm]). The results of both approaches coincided in that they identified arlRS as a repressor of biofilm development under both steady-state and flow conditions. The arlRS mutant exhibited an increased initial attachment as well as increased accumulation of poly-N-acetylglucosamine (PNAG). However, the biofilm formation of the arlRS mutant was not affected when the icaADBC operon was deleted, indicating that PNAG is not an essential compound of the biofilm matrix produced in HHWm. Disruption of the major autolysin gene, atl, did not produce any effect on the biofilm phenotype of an arlRS mutant. Epistatic experiments with global regulators involved in staphylococcal-biofilm formation indicated that sarA deletion abolished, whereas agr deletion reinforced, the biofilm development promoted by the arlRS mutation. PMID:16030226

  16. Land subsidence caused by withdrawal of oil and gas in the Gulf coastal plain - The Houston, Texas, case history

    SciTech Connect

    Holzer, T.L. )

    1990-09-01

    The extensive network of geodetic leveling lines in the Houston-Galveston, Texas, area, where at least 110 oil and gas fields have been developed, provides the most comprehensive opportunity in the Gulf Coast to search for the occurrence of land subsidence caused by withdrawal of oil and gas. Although the evaluation is complicated by regional subsidence caused by a decline of ground-water level in aquifers beneath the area, subsidence caused by oil and gas withdrawal can be examined by searching for local increases of subsidence at oil and gas fields crossed by leveling lines. Twenty-nine fields are crossed by lines with repeated leveling surveys. Subsidence profiles across these fields indicate local increases of subsidence at six fields-Alco-Mag, Chocolate Bayou, Goose Creek, Hastings, Mykawa, and South Houston. Although ground-water withdrawal is undoubtedly the most important factor contributing to the total subsidence at each field, oil and gas withdrawal may be partly responsible for the local increases. Except for Chocolate Bayou, the volume of petroleum production at each field was sufficient to account for the increase. The volume of petroleum production, however, in general is not a reliable index for predicting the local increase because land within many fields with significant production did not show local increases of subsidence. With the exception of the 1 m subsidence caused by petroleum withdrawal at Goose Creek (1917-1925), local increases of subsidence were less than 0.3 m.

  17. Measurement Scale of the SOLIS Vector Spectromagnetograph

    NASA Technical Reports Server (NTRS)

    Jones, Harrison P.; Harvey, John W.; Henney, Carl J.; Keller, Christoph U.; Malanushenko, Olena M.

    2004-01-01

    Longitudinal magnetograms obtained with thc SOLIS Vector Spectromagnetograph (VSM) during a cross-calibration period are compared with similar data from the NASA/NSO Spectromagnetograph (SPM) at the NSO/Kitt Peak Vacuum Telescope as well as with SOHO/MDI and GONG magnetogram. The VSM began observation at the University of Arizona agricultural test site and collaborative observations were obtained with both the VSM and SPM from 2003 Aug 05 through 2003 Sep 21 where the SPM was officially retired. The VSM replaces the SPM and continues the 3O-year NSO/Kitt Peak synoptic magnetogram record. Magnetograms are compared by equating histograms and, for selected examples, by pixel-by-pixel comparison of co-registered images. The VSM was not corrected for polarization crosstalk and was operated without hast guiding. Solar activity was at best moderate during this period. Over the range of observed fields, the VSM magnetograms show greatly improved sensitivity but are otherwise virtually identical with "raw" SPM magnetogram. GONG magnetograms are also closely comparable with the SPM while MDI flux values tend to be stronger by a factor of 1.2 - 1.4. Dependence of the results on seeing will be discussed. Partial funding for this work was provided through Solar and Heliospheric Research Supporting Research and Technology grants from NASA's Office of Space Sciences.

  18. Dynamic semiparametric Bayesian models for genetic mapping of complex trait with irregular longitudinal data.

    PubMed

    Das, Kiranmoy; Li, Jiahan; Fu, Guifang; Wang, Zhong; Li, Runze; Wu, Rongling

    2013-02-10

    Many phenomena of fundamental importance to biology and biomedicine arise as a dynamic curve, such as organ growth and HIV dynamics. The genetic mapping of these traits is challenged by longitudinal variables measured at irregular and possibly subject-specific time points, in which case nonnegative definiteness of the estimated covariance matrix needs to be guaranteed. We present a semiparametric approach for genetic mapping within the mixture-model setting by jointly modeling mean and covariance structures for irregular longitudinal data. Penalized spline is used to model the mean functions of individual quantitative trait locus (QTL) genotypes as latent variables, whereas an extended generalized linear model is used to approximate the covariance matrix. The parameters for modeling the mean-covariances are estimated by MCMC, using the Gibbs sampler and the Metropolis-Hastings algorithm. We derive the full conditional distributions for the mean and covariance parameters and compute Bayes factors to test the hypothesis about the existence of significant QTLs. We used the model to screen the existence of specific QTLs for age-specific change of body mass index with a sparse longitudinal data set. The new model provides powerful means for broadening the application of genetic mapping to reveal the genetic control of dynamic traits.

  19. Stochastic Tracking of Infection in a CF Lung

    PubMed Central

    Zarei, Sara; Mirtar, Ali; Rohwer, Forest; Salamon, Peter

    2014-01-01

    Magnetic Resonance Imaging (MRI) and Computed Tomography (CT) scan are the two ubiquitous imaging sources that physicians use to diagnose patients with Cystic Fibrosis (CF) or any other Chronic Obstructive Pulmonary Disease (COPD). Unfortunately the cost constraints limit the frequent usage of these medical imaging procedures. In addition, even though both CT scan and MRI provide mesoscopic details of a lung, in order to obtain microscopic information a very high resolution is required. Neither MRI nor CT scans provide micro level information about the location of infection in a binary tree structure the binary tree structure of the human lung. In this paper we present an algorithm that enhances the current imaging results by providing estimated micro level information concerning the location of the infection. The estimate is based on a calculation of the distribution of possible mucus blockages consistent with available information using an offline Metropolis-Hastings algorithm in combination with a real-time interpolation scheme. When supplemented with growth rates for the pockets of mucus, the algorithm can also be used to estimate how lung functionality as manifested in spirometric tests will change in patients with CF or COPD. PMID:25360611

  20. Presence of viral proteins in drinkable water--sufficient condition to consider water a vector of viral transmission?

    PubMed

    Gutiérrez, M F; Alvarado, M V; Martínez, E; Ajami, N J

    2007-01-01

    In order to determine the role of water as a possible vector for transmission of the most prevalent enteric viruses affecting infantile populations, 226 water samples were collected from Facatativa's (Colombian municipality located 30km away from Bogotá) water works in the years 2000, 2002, and 2005. The samples were clarified and virus was concentrated by filtering and ultrafiltering techniques. The presence of viral protein (VP) was assessed by enzyme immunoassay method (EIA) and viral RNA presence was detected by reverse trascriptase and polymerase chain reaction (RT-PCR). Using these techniques, one sample positive for Astrovirus (HAstV) was found in a sample collected from the river that supplies the aqueduct, two samples positive for Norovirus (NV) from fresh treated potable water and 13 samples positive for Rotavirus (RV), some in water from the plant during treatment and others from treated fresh water. RT-PCR inhibitors were also found in water samples obtained from the plant and in the fresh treated water. No inhibitors were found in the river water. VP, but no nucleic acid, was detected in the water samples at different stages of treatment, thus suggesting that the virus might have been complete and infectious at some stage prior to water purification.

  1. Identification of a vacuolar proton channel that triggers the bioluminescent flash in dinoflagellates

    PubMed Central

    Rodriguez, Juan D.; Haq, Saddef; Bachvaroff, Tsvetan; Nowak, Kristine F.; Nowak, Scott J.; Morgan, Deri; Cherny, Vladimir V.; Sapp, Maredith M.; Bernstein, Steven; Bolt, Andrew; DeCoursey, Thomas E.; Place, Allen R.; Smith, Susan M. E.

    2017-01-01

    In 1972, J. Woodland Hastings and colleagues predicted the existence of a proton selective channel (HV1) that opens in response to depolarizing voltage across the vacuole membrane of bioluminescent dinoflagellates and conducts protons into specialized luminescence compartments (scintillons), thereby causing a pH drop that triggers light emission. HV1 channels were subsequently identified and demonstrated to have important functions in a multitude of eukaryotic cells. Here we report a predicted protein from Lingulodinium polyedrum that displays hallmark properties of bona fide HV1, including time-dependent opening with depolarization, perfect proton selectivity, and characteristic ΔpH dependent gating. Western blotting and fluorescence confocal microscopy of isolated L. polyedrum scintillons immunostained with antibody to LpHV1 confirm LpHV1’s predicted organellar location. Proteomics analysis demonstrates that isolated scintillon preparations contain peptides that map to LpHV1. Finally, Zn2+ inhibits both LpHV1 proton current and the acid-induced flash in isolated scintillons. These results implicate LpHV1 as the voltage gated proton channel that triggers bioluminescence in L. polyedrum, confirming Hastings’ hypothesis. The same channel likely mediates the action potential that communicates the signal along the tonoplast to the scintillon. PMID:28178296

  2. A Good Death.

    PubMed

    Powell, Tia; Hulkower, Adira

    2017-01-01

    A good death is hard to find. Family members tell us that loved ones die in the wrong place-the hospital-and do not receive high-quality care at the end of life. This issue of the Hastings Center Report offers two articles from authors who strive to provide good end-of-life care and to prevent needless suffering. We agree with their goals, but we have substantial reservations about the approaches they recommend. Respect for the decisions of patients and their surrogates is a relatively new and still vulnerable aspect of medical care. For thousands of years, patients and surrogates had no say in medical decision-making. Today, standards support shared decision-making, but these articles both carve out exceptions to those standards, limiting the rights of patients and families in decisions about specific end-of-life treatments. As bioethics consultants in an acute care setting, we frequently confront conflicts similar to those described by Jeffrey Berger and by Ellen Robinson and colleagues. In such cases, our service emphasizes redoubled efforts at communication and mediation. Focusing on goals and values, rather than interventions, produces the best possible collaboration in health care decision-making. Cases in which we would overturn a surrogate's recommendations regarding palliative sedation or do-not-resuscitate orders are rare and require careful processes and clear evidence that the surrogate's choice is contrary to patient values.

  3. Learn-as-you-go acceleration of cosmological parameter estimates

    SciTech Connect

    Aslanyan, Grigor; Easther, Richard; Price, Layne C. E-mail: r.easther@auckland.ac.nz

    2015-09-01

    Cosmological analyses can be accelerated by approximating slow calculations using a training set, which is either precomputed or generated dynamically. However, this approach is only safe if the approximations are well understood and controlled. This paper surveys issues associated with the use of machine-learning based emulation strategies for accelerating cosmological parameter estimation. We describe a learn-as-you-go algorithm that is implemented in the Cosmo++ code and (1) trains the emulator while simultaneously estimating posterior probabilities; (2) identifies unreliable estimates, computing the exact numerical likelihoods if necessary; and (3) progressively learns and updates the error model as the calculation progresses. We explicitly describe and model the emulation error and show how this can be propagated into the posterior probabilities. We apply these techniques to the Planck likelihood and the calculation of ΛCDM posterior probabilities. The computation is significantly accelerated without a pre-defined training set and uncertainties in the posterior probabilities are subdominant to statistical fluctuations. We have obtained a speedup factor of 6.5 for Metropolis-Hastings and 3.5 for nested sampling. Finally, we discuss the general requirements for a credible error model and show how to update them on-the-fly.

  4. Stability of green fluorescent protein using luminescence spectroscopy: is GFP applicable to field analysis of contaminants?

    PubMed

    Smith, C B; Anderson, J E; Fischer, R L; Webb, S R

    2002-01-01

    Green fluorescent protein (GFP) was first isolated in the early 1970s for experimental use from coelenterates or the Pacific jellyfish. Aequorea victoria (Morin and Hastings, 1971). GFP has since become a favored biomarker in the photophysical analysis of molecular and cell biology because of its strong intrinsic visible fluorescence and the feasibility of fusing it to other proteins without affecting their normal functions (Creemers et al., 2000). Here we report using Bacillus subtilis expressing GFP to evaluate the influence of different environmental pH conditions on GFP fluorescence. Emission acquisitions were configured to excite at 471 nm and detect at an emission from 490 to 650 nm at 1-nm increments. Fluorescence intensity was significantly better at pH 7 (4.2 x 105 cps; P-value < 0.01) than at acid or alkaline conditions. GFP is a good biomarker for environments near netural conditions: however, GFP may be unsuitable where soils or waters are below or above pH 7 because of loss in fluorescence intensity. Alternative fluorescent markers and delivery systems must be examined in different environments to optimize responses from bioreporter molecules.

  5. Bayesian model comparison of nonlinear structural equation models with missing continuous and ordinal categorical data.

    PubMed

    Lee, Sik-Yum; Song, Xin-Yuan

    2004-05-01

    Missing data are very common in behavioural and psychological research. In this paper, we develop a Bayesian approach in the context of a general nonlinear structural equation model with missing continuous and ordinal categorical data. In the development, the missing data are treated as latent quantities, and provision for the incompleteness of the data is made by a hybrid algorithm that combines the Gibbs sampler and the Metropolis-Hastings algorithm. We show by means of a simulation study that the Bayesian estimates are accurate. A Bayesian model comparison procedure based on the Bayes factor and path sampling is proposed. The required observations from the posterior distribution for computing the Bayes factor are simulated by the hybrid algorithm in Bayesian estimation. Our simulation results indicate that the correct model is selected more frequently when the incomplete records are used in the analysis than when they are ignored. The methodology is further illustrated with a real data set from a study concerned with an AIDS preventative intervention for Filipina sex workers.

  6. A Gibbs Sampler for Learning DAGs

    PubMed Central

    Goudie, Robert J. B.; Mukherjee, Sach

    2017-01-01

    We propose a Gibbs sampler for structure learning in directed acyclic graph (DAG) models. The standard Markov chain Monte Carlo algorithms used for learning DAGs are random-walk Metropolis-Hastings samplers. These samplers are guaranteed to converge asymptotically but often mix slowly when exploring the large graph spaces that arise in structure learning. In each step, the sampler we propose draws entire sets of parents for multiple nodes from the appropriate conditional distribution. This provides an efficient way to make large moves in graph space, permitting faster mixing whilst retaining asymptotic guarantees of convergence. The conditional distribution is related to variable selection with candidate parents playing the role of covariates or inputs. We empirically examine the performance of the sampler using several simulated and real data examples. The proposed method gives robust results in diverse settings, outperforming several existing Bayesian and frequentist methods. In addition, our empirical results shed some light on the relative merits of Bayesian and constraint-based methods for structure learning.

  7. Saving Science by Doing Less of It?

    PubMed

    Kaebnick, Gregory E

    2016-11-01

    In the current issue of The New Atlantis, Daniel Sarewitz, professor of science and society at Arizona State University, argues that science is broken because it is managed and judged by scientists themselves, operating under Vannevar Bush's famous 1945 declaration that scientific progress depends on the "free play of free intellects … dictated by their curiosity." With that scientific agenda, society ends up with a lot of unnecessary, uncoordinated, and unproductive research. To save science, holds Sarewitz, we need to put it in the hands of people who are looking for practical solutions to specific problems. In one article in this issue of the Hastings Center Report (November-December 2016), Kirstin Borgerson poses a question in this same conceptual space: are there too many clinical trials? Other pieces in the issue cover a mix of topics: the lead article addresses some of the challenges that will have to be faced as "artificial organs" become available, a third article looks at how crowdfunding sites like GoFundMe can be used to make public appeals for medical funding, and a special report found in a supplement to the issue offers a round of analysis and recommendations about the provision of medical care to professional football players.

  8. Developing a cosmic ray muon sampling capability for muon tomography and monitoring applications

    NASA Astrophysics Data System (ADS)

    Chatzidakis, S.; Chrysikopoulou, S.; Tsoukalas, L. H.

    2015-12-01

    In this study, a cosmic ray muon sampling capability using a phenomenological model that captures the main characteristics of the experimentally measured spectrum coupled with a set of statistical algorithms is developed. The "muon generator" produces muons with zenith angles in the range 0-90° and energies in the range 1-100 GeV and is suitable for Monte Carlo simulations with emphasis on muon tomographic and monitoring applications. The muon energy distribution is described by the Smith and Duller (1959) [35] phenomenological model. Statistical algorithms are then employed for generating random samples. The inverse transform provides a means to generate samples from the muon angular distribution, whereas the Acceptance-Rejection and Metropolis-Hastings algorithms are employed to provide the energy component. The predictions for muon energies 1-60 GeV and zenith angles 0-90° are validated with a series of actual spectrum measurements and with estimates from the software library CRY. The results confirm the validity of the phenomenological model and the applicability of the statistical algorithms to generate polyenergetic-polydirectional muons. The response of the algorithms and the impact of critical parameters on computation time and computed results were investigated. Final output from the proposed "muon generator" is a look-up table that contains the sampled muon angles and energies and can be easily integrated into Monte Carlo particle simulation codes such as Geant4 and MCNP.

  9. Bayesian analysis of the flutter margin method in aeroelasticity

    SciTech Connect

    Khalil, Mohammad; Poirel, Dominique; Sarkar, Abhijit

    2016-08-27

    A Bayesian statistical framework is presented for Zimmerman and Weissenburger flutter margin method which considers the uncertainties in aeroelastic modal parameters. The proposed methodology overcomes the limitations of the previously developed least-square based estimation technique which relies on the Gaussian approximation of the flutter margin probability density function (pdf). Using the measured free-decay responses at subcritical (preflutter) airspeeds, the joint non-Gaussain posterior pdf of the modal parameters is sampled using the Metropolis–Hastings (MH) Markov chain Monte Carlo (MCMC) algorithm. The posterior MCMC samples of the modal parameters are then used to obtain the flutter margin pdfs and finally the flutter speed pdf. The usefulness of the Bayesian flutter margin method is demonstrated using synthetic data generated from a two-degree-of-freedom pitch-plunge aeroelastic model. The robustness of the statistical framework is demonstrated using different sets of measurement data. In conclusion, it will be shown that the probabilistic (Bayesian) approach reduces the number of test points required in providing a flutter speed estimate for a given accuracy and precision.

  10. Bayesian analysis of the flutter margin method in aeroelasticity

    DOE PAGES

    Khalil, Mohammad; Poirel, Dominique; Sarkar, Abhijit

    2016-08-27

    A Bayesian statistical framework is presented for Zimmerman and Weissenburger flutter margin method which considers the uncertainties in aeroelastic modal parameters. The proposed methodology overcomes the limitations of the previously developed least-square based estimation technique which relies on the Gaussian approximation of the flutter margin probability density function (pdf). Using the measured free-decay responses at subcritical (preflutter) airspeeds, the joint non-Gaussain posterior pdf of the modal parameters is sampled using the Metropolis–Hastings (MH) Markov chain Monte Carlo (MCMC) algorithm. The posterior MCMC samples of the modal parameters are then used to obtain the flutter margin pdfs and finally the fluttermore » speed pdf. The usefulness of the Bayesian flutter margin method is demonstrated using synthetic data generated from a two-degree-of-freedom pitch-plunge aeroelastic model. The robustness of the statistical framework is demonstrated using different sets of measurement data. In conclusion, it will be shown that the probabilistic (Bayesian) approach reduces the number of test points required in providing a flutter speed estimate for a given accuracy and precision.« less

  11. Somatic cell counts, mastitis and milk production in selected Ontario dairy herds.

    PubMed Central

    Barnum, D A; Meek, A H

    1982-01-01

    Somatic cell counts were performed monthly on bulk tank milk samples for all producers in the Ontario counties of Hastings, Lennox/Addington and Prince Edward throughout 1978 and 1979. Other data were obtained via a structured questionnaire and from the records of the Ontario Milk Marketing Board. Many producers have not adopted practices that have been advocated for the integrated control of mastitis. For example, 43.3% of producers surveyed used single service paper towels, 63.3% regularly used teat dip and 56.5% dry cow therapy. The mean of the average monthly somatic cell count for all producers for 1978 was 621.1 x 10(3) cells/mL. This latter value was used to divide the producers into case (higher than average) and control (lower than average) groups. Control herds averaged 95.9 liters more shipped milk per cow per month than case herds. Milk from control herds averaged 0.22 percentage points higher than case herds for each of average fat and lactose, and 0.16 percentage points higher for protein. The linear regression of monthly shipped milk on the respective monthly bulk tank somatic cell count indicated a loss of 13.26 L/cow/month for each 100,000 increase in somatic cell count. PMID:7200385

  12. T2-weighted balanced SSFP imaging (T2-TIDE) using variable flip angles.

    PubMed

    Paul, Dominik; Markl, Michael; Fautz, Hans-Peter; Hennig, Jürgen

    2006-07-01

    A new technique for acquiring T2-weighted, balanced steady-state free precession (b-SSFP) images is presented. Based on the recently proposed transition into driven equilibrium (TIDE) method, T2-TIDE uses a special flip angle scheme to achieve T2-weighted signal decay during the transient phase. In combination with half-Fourier image acquisition, T2-weighted images can be obtained using T2-TIDE. Numerical simulations were performed to analyze the signal behavior of T2-TIDE in comparison with TSE and b-SSFP. The results indicate identical signal evolution of T2-TIDE and TSE during the transient phase. T2-TIDE was used in phantom experiments, and quantitative ROI analysis shows a linear relationship between TSE and T2-TIDE SNR values. T2-TIDE was also applied to abdominal and head imaging on healthy volunteers. The resulting images were analyzed quantitatively and compared with standard T2-weighted and standard b-SSFP methods. T2-TIDE images clearly revealed T2 contrast and less blurring compared to T2-HASTE images. In combination with a magnetization preparation technique, STIR-weighted images were obtained. T2-TIDE is a robust technique for acquiring T2-weighted images while exploiting the advantages of b-SSFP imaging, such as high signal-to-noise ratio (SNR) and short TRs.

  13. Characterization of Interstellar Organic Molecules

    SciTech Connect

    Gencaga, Deniz; Knuth, Kevin H.; Carbon, Duane F.

    2008-11-06

    Understanding the origins of life has been one of the greatest dreams throughout history. It is now known that star-forming regions contain complex organic molecules, known as Polycyclic Aromatic Hydrocarbons (PAHs), each of which has particular infrared spectral characteristics. By understanding which PAH species are found in specific star-forming regions, we can better understand the biochemistry that takes place in interstellar clouds. Identifying and classifying PAHs is not an easy task: we can only observe a single superposition of PAH spectra at any given astrophysical site, with the PAH species perhaps numbering in the hundreds or even thousands. This is a challenging source separation problem since we have only one observation composed of numerous mixed sources. However, it is made easier with the help of a library of hundreds of PAH spectra. In order to separate PAH molecules from their mixture, we need to identify the specific species and their unique concentrations that would provide the given mixture. We develop a Bayesian approach for this problem where sources are separated from their mixture by Metropolis Hastings algorithm. Separated PAH concentrations are provided with their error bars, illustrating the uncertainties involved in the estimation process. The approach is demonstrated on synthetic spectral mixtures using spectral resolutions from the Infrared Space Observatory (ISO). Performance of the method is tested for different noise levels.

  14. Comparative reliability studies and analysis of Au, Pd-coated Cu and Pd-doped Cu wire in microelectronics packaging.

    PubMed

    Chong Leong, Gan; Uda, Hashim

    2013-01-01

    This paper compares and discusses the wearout reliability and analysis of Gold (Au), Palladium (Pd) coated Cu and Pd-doped Cu wires used in fineline Ball Grid Array (BGA) package. Intermetallic compound (IMC) thickness measurement has been carried out to estimate the coefficient of diffusion (Do) under various aging conditions of different bonding wires. Wire pull and ball bond shear strengths have been analyzed and we found smaller variation in Pd-doped Cu wire compared to Au and Pd-doped Cu wire. Au bonds were identified to have faster IMC formation, compared to slower IMC growth of Cu. The obtained weibull slope, β of three bonding wires are greater than 1.0 and belong to wearout reliability data point. Pd-doped Cu wire exhibits larger time-to-failure and cycles-to-failure in both wearout reliability tests in Highly Accelerated Temperature and Humidity (HAST) and Temperature Cycling (TC) tests. This proves Pd-doped Cu wire has a greater potential and higher reliability margin compared to Au and Pd-coated Cu wires.

  15. Painlevé Representation of Tracy-Widom{_β} Distribution for {β} = 6

    NASA Astrophysics Data System (ADS)

    Rumanov, Igor

    2016-03-01

    In Rumanov (J Math Phys 56:013508, 2015), we found explicit Lax pairs for the soft edge of beta ensembles with even integer values of {β}. Using this general result, the case {β = 6} is further considered here. This is the smallest even {β}, when the corresponding Lax pair and its relation to Painlevé II (PII) have not been known before, unlike cases {β = 2} and 4. It turns out that again everything can be expressed in terms of the Hastings-McLeod solution of PII. In particular, a second order nonlinear ordinary differential equation (ODE) for the logarithmic derivative of Tracy-Widom distribution for {β = 6} involving the PII function in the coefficients is found, which allows one to compute asymptotics for the distribution function. The ODE is a consequence of a linear system of three ODEs for which the local singularity analysis yields series solutions with exponents in the set 4/3, 1/3 and -2/3.

  16. The psychometric properties of the difficult behavior self-efficacy scale.

    PubMed

    Oh, Hyun-Kyoung; Kozub, Francis M

    2010-07-01

    The study was designed to estimate the psychometric properties of Hastings and Brown's (2002a) Difficult Behavior Self-efficacy Scale. Participants were two samples of physical educators teaching in Korea (n=229) and the United States (U.S.; n=139). An initial translation of the questionnaire to Korean and pilot study were conducted along with the larger study using a confirmatory factor analysis procedure. Internal consistency estimates (weighed Omega) for the five-item scale were 0.88 both the Korean and U.S. samples. The average variances extracted for the one factor were 0.59 for the total data set and 0.57 each for the Korean and U.S. samples. Confirmatory factor analysis supported a five-item, unidimensional model for self-efficacy for the total sample: Goodness of Fit Index (GFI)=0.97, Nonnormed Fit Index (NNFI)=0.95, Comparative Fit Index (CFI)=0.98, and Standardized Root Mean Square Residual (SRMR)=0.03. Only the Root Mean Square Error of Approximation (RMSEA=0.12) fell below criterion levels of acceptable fit, with similar fit indices occurring in separate analyses of the Korean and U.S. samples. Invariance testing across the two samples supported metric invariance (similarity of factor loadings) but not scalar invariance (U.S. means higher on all five items). The factor structure for the self-efficacy scale provides an initial estimate of validity and internal consistency for use with different teacher groups.

  17. Fed-batch optimization of alpha-amylase and protease-producing Bacillus subtilis using Markov chain methods.

    PubMed

    Skolpap, Wanwisa; Scharer, J M; Douglas, P L; Moo-Young, M

    2004-06-20

    A stoichiometry-based model for the fed-batch culture of the recombinant bacterium Bacillus subtilis ATCC 6051a, producing extracellular alpha-amylase as a desirable product and proteases as undesirable products, was developed and verified. The model was then used for optimizing the feeding schedule in fed-batch culture. To handle higher-order model equations (14 state variables), an optimization methodology for the dual-enzyme system is proposed by integrating Pontryagin's optimum principle with fermentation measurements. Markov chain Monte Carlo (MCMC) procedures were appropriate for model parameter and decision variable estimation by using a priori parameter distributions reflecting the experimental results. Using a simplified Metropolis-Hastings algorithm, the specific productivity of alpha-amylase was maximized and the optimum path was confirmed by experimentation. The optimization process predicted a further 14% improvement of alpha-amylase productivity that could not be realized because of the onset of sporulation. Among the decision variables, the switching time from batch to fed-batch operation (t(s)) was the most sensitive decision variable.

  18. Estimating rare events in biochemical systems using conditional sampling

    NASA Astrophysics Data System (ADS)

    Sundar, V. S.

    2017-01-01

    The paper focuses on development of variance reduction strategies to estimate rare events in biochemical systems. Obtaining this probability using brute force Monte Carlo simulations in conjunction with the stochastic simulation algorithm (Gillespie's method) is computationally prohibitive. To circumvent this, important sampling tools such as the weighted stochastic simulation algorithm and the doubly weighted stochastic simulation algorithm have been proposed. However, these strategies require an additional step of determining the important region to sample from, which is not straightforward for most of the problems. In this paper, we apply the subset simulation method, developed as a variance reduction tool in the context of structural engineering, to the problem of rare event estimation in biochemical systems. The main idea is that the rare event probability is expressed as a product of more frequent conditional probabilities. These conditional probabilities are estimated with high accuracy using Monte Carlo simulations, specifically the Markov chain Monte Carlo method with the modified Metropolis-Hastings algorithm. Generating sample realizations of the state vector using the stochastic simulation algorithm is viewed as mapping the discrete-state continuous-time random process to the standard normal random variable vector. This viewpoint opens up the possibility of applying more sophisticated and efficient sampling schemes developed elsewhere to problems in stochastic chemical kinetics. The results obtained using the subset simulation method are compared with existing variance reduction strategies for a few benchmark problems, and a satisfactory improvement in computational time is demonstrated.

  19. Using intraoperative MRI to assess bleeding

    NASA Astrophysics Data System (ADS)

    Liu, Haiying; Hall, Walter A.; Martin, Alastair J.; Truwit, Charles L.

    2001-05-01

    Immediate detector of any surgically induced hemorrhage prior to the closure is important for minimizing the unnecessary post surgical complications. In the case of hemorrhage, the surgical site of interests often involves hemorrhagic blood in the presence of CSF as well as air pockets. It is known that the hemorrhagic blood or air has a different magnetic susceptibility from its surrounding tissue, and CSF has long T1 and T2. Based on these differences, a set of complimentary imaging techniques (T2, FLAIR, and GE) were optimized to reveal the existence of surgically induced acute hemorrhage. Among 330 neurosurgical cases, one relatively severe hemorrhage has been successfully found intra-operatively using the concept. During the case, a new hyperintense area close to the primary motor cortex was initially noticed on T2 weighted HASTE images. As soon as it was found to increase in size rapidly, the patient was treated immediately via craniotomy for aspiration of the intra-parenchymal blood. Owing to early detection and treatment, the patient was completely free of motor deficits. Besides, there were ten much less severe hemorrhages have been noticed using the method. The proper post-surgical care was planned to closely follow-up the patient for any sign of hemorrhage.

  20. A MARKOV CHAIN MONTE CARLO ALGORITHM FOR ANALYSIS OF LOW SIGNAL-TO-NOISE COSMIC MICROWAVE BACKGROUND DATA

    SciTech Connect

    Jewell, J. B.; O'Dwyer, I. J.; Huey, Greg; Gorski, K. M.; Eriksen, H. K.; Wandelt, B. D. E-mail: h.k.k.eriksen@astro.uio.no

    2009-05-20

    We present a new Markov Chain Monte Carlo (MCMC) algorithm for cosmic microwave background (CMB) analysis in the low signal-to-noise regime. This method builds on and complements the previously described CMB Gibbs sampler, and effectively solves the low signal-to-noise inefficiency problem of the direct Gibbs sampler. The new algorithm is a simple Metropolis-Hastings sampler with a general proposal rule for the power spectrum, C {sub l}, followed by a particular deterministic rescaling operation of the sky signal, s. The acceptance probability for this joint move depends on the sky map only through the difference of {chi}{sup 2} between the original and proposed sky sample, which is close to unity in the low signal-to-noise regime. The algorithm is completed by alternating this move with a standard Gibbs move. Together, these two proposals constitute a computationally efficient algorithm for mapping out the full joint CMB posterior, both in the high and low signal-to-noise regimes.

  1. The Declaration of Hawaii and Clarence Blomquist.

    PubMed

    Ottosson, J O

    2000-01-01

    The international code of ethics of psychiatry, the Declaration of Hawaii was in the main the achievement of Clarence Blomquist. There were several prerequisites for the success of this work. 1. The unique profile of the education of Clarence Blomquist, combining training to be a specialist in psychiatry with a doctor's degree in practical philosophy. 2. An outstanding competence in analyzing complicated issues and in putting thoughts into words. 3. The courage to challenge the Hippocratic ethics and adapt the principles of ethics to modern health care. 4. A scholarship at the Institute of Society, Ethics and the Life Sciences, Hastings-on-Hudson, New York, where he could test his ideas in an intellectual interdisciplinary atmosphere. 5. Support from the late Professor Leo Eitinger, Norway and Professor Gerdt Wretmark, Sweden, who together with Clarence Blomquist constituted a task force on ethics of the World Psychiatric Association. 6. A continuous backing-up by Dr Denis Leigh, the then secretary general of the World Psychiatric Association. Denis Leigh was convinced that a code of ethics was the only means to reconcile the various member countries on issues of misuse of psychiatry and, in addition, would raise the quality of psychiatric care throughout the world.

  2. δ 18Osw estimate for Globigerinoides ruber from core-top sediments in the East China Sea

    NASA Astrophysics Data System (ADS)

    Horikawa, Keiji; Kodaira, Tomohiro; Zhang, Jing; Murayama, Masafumi

    2015-12-01

    The paired analyses of the Mg/Ca ratio and oxygen isotopic composition ( δ 18Oc) of surface-dwelling planktonic foraminifera have become a widely used method for reconstructing the oxygen isotopic composition of ambient seawater ( δ 18Osw) as a robust proxy for surface salinity. Globigerinoides ruber ( G. ruber) is a mixed-layer dweller, and its fossil shell is an ideal archive for recording past sea surface water conditions, such as those caused by variability in the East Asian summer monsoon (EASM). Here, we investigate the validity of shell-derived δ 18Osw estimates for G. ruber using core-top sediments from the East China Sea (ECS). First, we determined a local δ 18Osw-salinity equation for the eastern part of the ECS in July [ δ 18Osw = -7.74 + 0.23 × salinity]. Then, we calculated δ 18Osw from core-top δ 18Oc and Mg/Ca values in G. ruber using the δ 18Oc-temperature equation of Bemis et al. (Paleoceanography 13(2):150-160, 1998) and the Mg/Ca-temperature equation of Hastings et al. (EOS 82:PP12B-10, 2001). The core-top δ 18Osw and salinity were estimated to be in the ranges of -0.2 to +0.39 ‰ and 33.7 to 34.5, respectively, which fall close to the local δ 18Osw-salinity regression line. The core-top data showed that the Mg/Ca-temperature calibration by Hastings et al. (EOS 82:PP12B-10, 2001) and the δ 18Oc-temperature equation by Bemis et al. (Paleoceanography 13(2):150-160, 1998) are appropriate for calculating δ 18Osw in the ECS. Furthermore, we measured core-top Ba/Ca ratios of G. ruber (Ba/Ca G. ruber ), which ranged from 0.66 to 2.82 μmol mol-1. There was not a significant relationship between the salinity and Ba/Ca G. ruber ratios due to the highly variable Ba/Ca G. ruber data. Given the seawater Ba/Ca data and the published partition coefficient for Ba ( D Ba = 0.15-0.22), pristine Ba/Ca G. ruber ratios at northern Okinawa Trough sites should be less than 0.84 μmol mol-1. Anomalously high Ba/Ca G. ruber ratios (>0.84 μmol mol-1) might

  3. Exposants geometriques des modeles de boucles dilues et idempotents des TLn-modules de la chaine de spins XXZ

    NASA Astrophysics Data System (ADS)

    Provencher, Guillaume

    This thesis is concerned with the study of critical phenomena for two-dimensional models on the lattice. Its results are contained in two articles: A first one, devoted to measuring geometric exponents, and a second one to the construction of idempotents for the XXZ spin chain projecting on indecomposable modules of the Temperley-Lieb algebra. Monte Carlo experiments, for a family of loop models in their dilute phase, are presented in the first article. Coined dilute loop models ( DLM ), this family is based upon an O (n) model introduced by Nienhuis (1990). It is defined by two coprime integers p, p' and an anisotropy parameter. In the continuum limit, DLM (p, p') is expected to yield a logarithmic conformal field theory of central charge c(kappa) = 13 - 6(kappa + kappa -1), where the ratio kappa = pp' is related to the loop gas fugacity beta = -2 cos pk . Critical exponents pertaining to valuable geometrical objects, namely the hull, external perimeter and red bonds, were measured. The Metropolis-Hastings algorithm, as well as several methods improving its efficiency, are presented. Despite the extrapolation of curves presenting large slopes, values as close as three to four digits from the theoretical predictions were attained through rigorous statistical analysis. The second article describes the decomposition of the XXZ spin chain Hilbert space ⊗n C2 using idempotents. The model of interest (Pasquier & Saleur (1990)) is described by a parameter-dependent Hamiltonian HXXZ (q), q ∈ Cx , expressible as a sum of elements of the Temperley-Lieb algebra TL n(q). The spectrum of HXXZ (q) in the continuum limit is also believed to be related to conformal field theories whose central charge is set by q. Using the quantum Schur-Weyl duality, an expression for the primitive idempotents of EndTLn ⊗n C2 , involving Uq sl2 elements, is obtained. These idempotents allow for the explicit construction of the indecomposable TLn-modules of ⊗ n C2 , all of which are

  4. How international is bioethics? A quantitative retrospective study

    PubMed Central

    2006-01-01

    Background Studying the contribution of individual countries to leading journals in a specific discipline can highlight which countries have the most impact on that discipline and whether a geographic bias exists. This article aims to examine the international distribution of publications in the field of bioethics. Methods Retrospective quantitative study of nine peer reviewed journals in the field of bioethics and medical ethics (Bioethics, Cambridge Quarterly of Healthcare Ethics, Hastings Center Report, Journal of Clinical Ethics, Journal of Medical Ethics, Kennedy Institute of Ethics Journal, Nursing Ethics, Christian Bioethics, and Theoretical Medicine and Bioethics). Results In total, 4,029 articles published between 1990 and 2003 were retrieved from the nine bioethical journals under study. The United States (59.3%, n = 2390), the United Kingdom (13.5%, n = 544), Canada (4%, n = 160) and Australia (3.8%, n = 154) had the highest number of publications in terms of absolute number of publications. When normalized to population size, smaller affluent countries, such as New Zealand, Finland and Sweden were more productive than the United States. The number of studies originating from the USA was decreasing in the period between 1990 and 2003. Conclusion While a lot of peer reviewed journals in the field of bioethics profile themselves as international journals, they certainly do not live up to what one would expect from an "international" journal. The fact that English speaking countries, and to a larger extent American authors, dominate the international journals in the field of bioethics is a clear geographic bias towards the bioethical discussions that are going on in these journals. PMID:16412229

  5. An introduction of Markov chain Monte Carlo method to geochemical inverse problems: Reading melting parameters from REE abundances in abyssal peridotites

    NASA Astrophysics Data System (ADS)

    Liu, Boda; Liang, Yan

    2017-04-01

    Markov chain Monte Carlo (MCMC) simulation is a powerful statistical method in solving inverse problems that arise from a wide range of applications. In Earth sciences applications of MCMC simulations are primarily in the field of geophysics. The purpose of this study is to introduce MCMC methods to geochemical inverse problems related to trace element fractionation during mantle melting. MCMC methods have several advantages over least squares methods in deciphering melting processes from trace element abundances in basalts and mantle rocks. Here we use an MCMC method to invert for extent of melting, fraction of melt present during melting, and extent of chemical disequilibrium between the melt and residual solid from REE abundances in clinopyroxene in abyssal peridotites from Mid-Atlantic Ridge, Central Indian Ridge, Southwest Indian Ridge, Lena Trough, and American-Antarctic Ridge. We consider two melting models: one with exact analytical solution and the other without. We solve the latter numerically in a chain of melting models according to the Metropolis-Hastings algorithm. The probability distribution of inverted melting parameters depends on assumptions of the physical model, knowledge of mantle source composition, and constraints from the REE data. Results from MCMC inversion are consistent with and provide more reliable uncertainty estimates than results based on nonlinear least squares inversion. We show that chemical disequilibrium is likely to play an important role in fractionating LREE in residual peridotites during partial melting beneath mid-ocean ridge spreading centers. MCMC simulation is well suited for more complicated but physically more realistic melting problems that do not have analytical solutions.

  6. Land leveling impact on surface runoff and soil losses: Estimation with coupled deterministic/stochastic models for a Québec agricultural field

    NASA Astrophysics Data System (ADS)

    Gagnon, Patrick; Chrétien, François; Thériault, Georges

    2017-01-01

    Land leveling impact on water quality had not received much attention for fields in humid continental climate. The objectives of this study were to isolate the impact of land leveling, performed on an agricultural field (Québec, Canada) in spring 2012, on runoff and TSS load and to make recommendations to attenuate adverse environmental impacts of land leveling, if any. A total of 66 runoff events, including 22 with total suspended sediments (TSS) load estimates, from 2010 to 2014 were analyzed. To this end, deterministic models were coupled to an adaptive Metropolis-Hastings algorithm to estimate the unknown distribution of the parameters representing the most important effects, namely land leveling, tillage, and crop cover. Simulated runoff events were generated by the hydrological model SWMM version 5 while simulated TSS loads were generated by an empirical equation based on the Revised Universal Soil Loss Equation version 2 (RUSLE2). Thanks to the algorithm used, it was demonstrated that land leveling significantly decreased total runoff volume at least for the two following years. The impact on peak flow was mixed: land leveling significantly decreased peak flow for a typical stratiform rainfall event but the effect was unclear for a typical convective rainfall event. Based on 90% confidence interval, TSS load increased from 10 to 1000 times immediately after land leveling (spring 2012) compared to pre-land leveling events. The TSS load increase remained significant one year after land leveling, with TSS loads 5-20 times higher compared to pre-land leveling events. It would thus be recommended to grow crops with high ground coverage ratios coupled with cover crops during the year when land leveling is done. Sediment retention structures could also be installed at the beginning of the land leveling process to provide protection against the short term and delayed impact on water quality.

  7. Changes in the social context and conduct of eating in four Nordic countries between 1997 and 2012.

    PubMed

    Holm, Lotte; Lauridsen, Drude; Lund, Thomas Bøker; Gronow, Jukka; Niva, Mari; Mäkelä, Johanna

    2016-08-01

    How have eating patterns changed in modern life? In public and academic debate concern has been expressed that the social function of eating may be challenged by de-structuration and the dissolution of traditions. We analyzed changes in the social context and conduct of eating in four Nordic countries over the period 1997-2012. We focused on three interlinked processes often claimed to be distinctive of modern eating: delocalization of eating from private households to commercial settings, individualization in the form of more eating alone, and informalization, implying more casual codes of conduct. We based the analysis on data from two surveys conducted in Denmark, Finland, Norway and Sweden in 1997 and 2012. The surveys reported in detail one day of eating in representative samples of adult populations in the four countries (N = 4823 and N = 8242). We compared data regarding where, with whom, and for how long people ate, and whether parallel activities took place while eating. While Nordic people's primary location for eating remained the home and the workplace, the practices of eating in haste, and while watching television increased and using tablets, computers and smartphones while eating was frequent in 2012. Propensity to eat alone increased slightly in Denmark and Norway, and decreased slightly in Sweden. While such practices vary with socio-economic background, regression analysis showed several changes were common across the Nordic populations. However, the new practice of using tablets, computers, and smartphones while eating was strongly associated with young age. Further, each of the practices appeared to be related to different types of meal. We conclude that while the changes in the social organization of eating were not dramatic, signs of individualization and informalization could be detected.

  8. Anthropogenic sulphur dioxide load over China as observed from different satellite sensors

    NASA Astrophysics Data System (ADS)

    Koukouli, M. E.; Balis, D. S.; van der A, Ronald Johannes; Theys, N.; Hedelt, P.; Richter, A.; Krotkov, N.; Li, C.; Taylor, M.

    2016-11-01

    China, with its rapid economic growth and immense exporting power, has been the focus of many studies during this previous decade quantifying its increasing emissions contribution to the Earth's atmosphere. With a population slowly shifting towards enlarged power and purchasing needs, the ceaseless inauguration of new power plants, smelters, refineries and industrial parks leads infallibly to increases in sulphur dioxide, SO2, emissions. The recent capability of next generation algorithms as well as new space-borne instruments to detect anthropogenic SO2 loads has enabled a fast advancement in this field. In the following work, algorithms providing total SO2 columns over China based on SCIAMACHY/Envisat, OMI/Aura and GOME2/MetopA observations are presented. The need for post-processing and gridding of the SO2 fields is further revealed in this work, following the path of previous publications. Further, it is demonstrated that the usage of appropriate statistical tools permits studying parts of the datasets typically excluded, such as the winter months loads. Focusing on actual point sources, such as megacities and known power plant locations, instead of entire provinces, monthly mean time series have been examined in detail. The sharp decline in SO2 emissions in more than 90%-95% of the locations studied confirms the recent implementation of government desulphurisation legislation; however, locations with increases, even for the previous five years, are also identified. These belong to provinces with emerging economies which are in haste to install power plants and are possibly viewed leniently by the authorities, in favour of growth. The SO2 load seasonality has also been examined in detail with a novel mathematical tool, with 70% of the point sources having a statistically significant annual cycle with highs in winter and lows in summer, following the heating requirements of the Chinese population.

  9. The development of posterior probability models in risk-based integrity modeling.

    PubMed

    Thodi, Premkumar N; Khan, Faisal I; Haddara, Mahmoud R

    2010-03-01

    There is a need for accurate modeling of mechanisms causing material degradation of equipment in process installation, to ensure safety and reliability of the equipment. Degradation mechanisms are stochastic processes. They can be best described using risk-based approaches. Risk-based integrity assessment quantifies the level of risk to which the individual components are subjected and provides means to mitigate them in a safe and cost-effective manner. The uncertainty and variability in structural degradations can be best modeled by probability distributions. Prior probability models provide initial description of the degradation mechanisms. As more inspection data become available, these prior probability models can be revised to obtain posterior probability models, which represent the current system and can be used to predict future failures. In this article, a rejection sampling-based Metropolis-Hastings (M-H) algorithm is used to develop posterior distributions. The M-H algorithm is a Markov chain Monte Carlo algorithm used to generate a sequence of posterior samples without actually knowing the normalizing constant. Ignoring the transient samples in the generated Markov chain, the steady state samples are rejected or accepted based on an acceptance criterion. To validate the estimated parameters of posterior models, analytical Laplace approximation method is used to compute the integrals involved in the posterior function. Results of the M-H algorithm and Laplace approximations are compared with conjugate pair estimations of known prior and likelihood combinations. The M-H algorithm provides better results and hence it is used for posterior development of the selected priors for corrosion and cracking.

  10. Probabilistic graphical model representation in phylogenetics.

    PubMed

    Höhna, Sebastian; Heath, Tracy A; Boussau, Bastien; Landis, Michael J; Ronquist, Fredrik; Huelsenbeck, John P

    2014-09-01

    Recent years have seen a rapid expansion of the model space explored in statistical phylogenetics, emphasizing the need for new approaches to statistical model representation and software development. Clear communication and representation of the chosen model is crucial for: (i) reproducibility of an analysis, (ii) model development, and (iii) software design. Moreover, a unified, clear and understandable framework for model representation lowers the barrier for beginners and nonspecialists to grasp complex phylogenetic models, including their assumptions and parameter/variable dependencies. Graphical modeling is a unifying framework that has gained in popularity in the statistical literature in recent years. The core idea is to break complex models into conditionally independent distributions. The strength lies in the comprehensibility, flexibility, and adaptability of this formalism, and the large body of computational work based on it. Graphical models are well-suited to teach statistical models, to facilitate communication among phylogeneticists and in the development of generic software for simulation and statistical inference. Here, we provide an introduction to graphical models for phylogeneticists and extend the standard graphical model representation to the realm of phylogenetics. We introduce a new graphical model component, tree plates, to capture the changing structure of the subgraph corresponding to a phylogenetic tree. We describe a range of phylogenetic models using the graphical model framework and introduce modules to simplify the representation of standard components in large and complex models. Phylogenetic model graphs can be readily used in simulation, maximum likelihood inference, and Bayesian inference using, for example, Metropolis-Hastings or Gibbs sampling of the posterior distribution.

  11. The Origin of the Large-Scale Structure in the Universe: Theoretical and Statistical Aspects

    NASA Astrophysics Data System (ADS)

    Rodriguez, Yeinzon

    2005-07-01

    We review some theoretical and statistical aspects of the origin of the large-scale structure in the Universe, in view of the two most widely known and accepted scenarios: the inflaton and the curvaton scenarios. Among the theoretical aspects, we point out the impossibility of having a low inflationary energy scale in the simplest curvaton model. A couple of modifications to the simplest setup are explored, corresponding to the implementation of a second (thermal) inflationary period whose end makes the curvaton field `heavy', triggering either its oscillations or immediate decay. Low scale inflation is then possible to attain with H_ast being as low as 1 TeV. Among the statistical aspects, we study the bispectrum B_zeta(k_1,k_2,k_3) of the primordial curvature perturbation zeta whose normalisation fnl gives information about the level of non-gaussianity in zeta. In connection with fnl, several conserved and/or gauge invariant quantities described as the second-order curvature perturbation have been given in the literature. We review each of these quantities showing how to interpret one in terms of the others, and analyze the respective expected fnl in both the inflaton and the curvaton scenarios as well as in other less known models for the generation of primordial perturbations and/or non-gaussianities. The delta N formalism turns out to be a powerful technique to compute fnl in multi-component slow-roll inflation, as the knowledge of the evolution of some family of unperturbed universes is the only requirement. We present for the first time this formalism and apply it to selected examples.

  12. Application of Markov Chain Monte Carlo Method to Mantle Melting: An Example from REE Abundances in Abyssal Peridotites

    NASA Astrophysics Data System (ADS)

    LIU, B.; Liang, Y.

    2015-12-01

    Markov chain Monte Carlo (MCMC) simulation is a powerful statistical method in solving inverse problems that arise from a wide range of applications, such as nuclear physics, computational biology, financial engineering, among others. In Earth sciences applications of MCMC are primarily in the field of geophysics [1]. The purpose of this study is to introduce MCMC to geochemical inverse problems related to trace element fractionation during concurrent melting, melt transport and melt-rock reaction in the mantle. MCMC method has several advantages over linearized least squares methods in inverting trace element patterns in basalts and mantle rocks. First, MCMC can handle equations that have no explicit analytical solutions which are required by linearized least squares methods for gradient calculation. Second, MCMC converges to global minimum while linearized least squares methods may be stuck at a local minimum or converge slowly due to nonlinearity. Furthermore, MCMC can provide insight into uncertainties of model parameters with non-normal trade-off. We use MCMC to invert for extent of melting, amount of trapped melt, and extent of chemical disequilibrium between the melt and residual solid from REE data in abyssal peridotites from Central Indian Ridge and Mid-Atlantic Ridge. In the first step, we conduct forward calculation of REE evolution with melting models in a reasonable model space. We then build up a chain of melting models according to Metropolis-Hastings algorithm to represent the probability of specific model. We show that chemical disequilibrium is likely to play an important role in fractionating LREE in residual peridotites. In the future, MCMC will be applied to more realistic but also more complicated melting models in which partition coefficients, diffusion coefficients, as well as melting and melt suction rates vary as functions of temperature, pressure and mineral compositions. [1]. Sambridge & Mosegarrd [2002] Rev. Geophys.

  13. Entanglement generation in periodically driven integrable systems: Dynamical phase transitions and steady state

    NASA Astrophysics Data System (ADS)

    Sen, Arnab; Nandy, Sourav; Sengupta, K.

    2016-12-01

    We study a class of periodically driven d -dimensional integrable models and show that after n drive cycles with frequency ω , pure states with non-area-law entanglement entropy Sn(l ) ˜lα (n ,ω ) are generated, where l is the linear dimension of the subsystem, and d -1 ≤α (n ,ω )≤d . The exponent α (n ,ω ) eventually approaches d (volume law) for large enough l when n →∞ . We identify and analyze the crossover phenomenon from an area (S ˜ld -1 for d ≥1 ) to a volume (S ˜ld ) law and provide a criterion for their occurrence which constitutes a generalization of Hastings's theorem to driven integrable systems in one dimension. We also find that Sn generically decays to S∞ as (ω/n ) (d +2 )/2 for fast and (ω/n ) d /2 for slow periodic drives; these two dynamical phases are separated by a topological transition in the eigenspectrum of the Floquet Hamiltonian. This dynamical transition manifests itself in the temporal behavior of all local correlation functions and does not require a critical point crossing during the drive. We find that these dynamical phases show a rich re-entrant behavior as a function of ω for d =1 models and also discuss the dynamical transition for d >1 models. Finally, we study entanglement properties of the steady state and show that singular features (cusps and kinks in d =1 ) appear in S∞ as a function of ω whenever there is a crossing of the Floquet bands. We discuss experiments which can test our theory.

  14. Adverse consequences of immunostimulation.

    PubMed

    Ponce, Rafael

    2008-01-01

    The therapeutic uses of immunostimulatory agents are generally in the treatments of infections or cancer. The traditional example of vaccination is one form of immunostimulation used in the prevention of pathogenic infections or cancer (e.g., human papillomavirus vaccine). Recombinant cytokines are increasingly used to stimulate immune system function. For example, interferon-alpha (IFNalpha) and interleukin (IL)-2 have been used to treat chronic hepatitis C virus infection and metastatic melanoma, respectively. In contrast, monoclonal antibodies are used to target malignant cells for elimination via antibody-dependent cytotoxicity mechanisms or apoptosis, including the anti-CD20 monoclonal antibody rituximab and the anti-CD56 monoclonal antibody alemtuzumab used in the treatment of B-cell malignancies, and the anti-erb2 receptor antibody trastuzumab used in the treatment of breast cancer. Finally, immunostimulation may develop via modulation of pathways involved in immune system regulation. For example, the anti-CD28 monoclonal antibody TGN1412 was developed as an agonist of regulatory T-cells for treatment of T-cell-mediated chronic inflammatory diseases or leukemias. A panel was convened to discuss potential toxicities associated with immunostimulation. At the Immunotoxicology IV meeting in 2006, a panel, moderated by Dr. Robert House (Dynport Vaccine Co., Frederick, MD), included Drs. Gary Burleson (Burleson Research Technologies, Inc., Raleigh, NC), Kenneth Hastings (US FDA, Center for Drug Evaluation and Research [CDER], Rockville, MD), Barbara Mounho (Amgen, Thousand Oaks, CA), Rafael Ponce (ZymoGenetics, Inc., Seattle, WA), Mark Wing (Huntington Life Sciences, Cambridgeshire, United Kingdom), Lauren Black (Navigators Consulting, Sparks, NV) and Anne Pilaro (US FDA, CDER, Rockville, MD). This paper reviews the major identified toxicities associated with immunostimulation, including the acute phase response, cell and tissue abnormalities/injury, cytokine

  15. Final Work Plan: Phase I Investigation at Bladen, Nebraska

    SciTech Connect

    LaFreniere, Lorraine M.; Yan, Eugene

    2014-07-01

    The village of Bladen is a town of population approximately 237 in the northwest part of Webster County, Nebraska, 30 mi southwest of Hastings and 140 mi southwest of Lincoln, Nebraska. In 2000, the fumigant-related compound carbon tetrachloride was detected in public water supply well PWS 68-1, at a trace level. Low-level contamination, below the maximum contamination level (MCL) of 5.0 μg/L, has been detected intermittently in well PWS 68-1 since 2000, including in the last sample taken in July 2013. In 2006, the village installed a new well, PWS 2006-1, that remains free of contamination. Because the carbon tetrachloride found in well PWS 68-1 might be linked to historical use of fumigants containing carbon tetrachloride at grain storage facilities, including its former facility in Bladen, the CCC/USDA is proposing an investigation to (1) delineate the source and extent of the carbon tetrachloride contamination potentially associated with its former facility, (2) characterize pathways and controlling factors for contaminant migration in the subsurface, and (3) establish a basis for estimating potential health and environmental risks. The work will be performed in accordance with the Intergovernmental Agreement established between the NDEQ and the Farm Service Agency of the USDA. The site investigation at Bladen will be implemented in phases, so that data collected and interpretations developed during each phase can be evaluated to determine if a subsequent phase of investigation is warranted and, if warranted, to provide effective guidance for the subsequent investigation activities. This Work Plan identifies the specific technical objectives and defines the scope of work proposed for the Phase I investigation by compiling and evaluating historical data. The proposed investigation activities will be performed on behalf of the CCC/USDA by the Environmental Science Division of Argonne National Laboratory. Argonne is a nonprofit, multidisciplinary research

  16. Towards interpreting nitrate-δ15N records in ice cores in terms of nitrogen oxide sources

    NASA Astrophysics Data System (ADS)

    Hastings, M. G.; Buffen, A. M.

    2011-12-01

    The isotopic composition of nitrate preserved in ice cores offers unique potential for reconstructing past contributions of nitrogen oxides (NOx = NO and NO2) to the atmosphere. Sources of NOx imprint a nitrogen stable isotopic (δ15N) signature, which can be conserved during subsequent oxidation to form nitrate. Major sources of NOx include fossil fuels combustion, biomass burning, microbial processes in soils, and lightning, and thus a quantitative tracer of emissions would help detail connections between the atmosphere, the biosphere, and climate. Unfortunately, the δ15N signatures of most NOx sources are not yet well enough constrained to allow for quantitative partitioning, though new methodology for directly collecting NOx for isotopic analysis is promising (Fibiger and Hastings, A43D-0265, AGU 2010). Still, a growing network of ice core δ15N records may offer insight into source signatures, as different sources are important to different regions of the world. For example, a 300-year ice core record of nitrate-δ15N from Summit, Greenland shows a clear and significant 12% (vs. N2) decrease since the Preindustrial that reflects emissions from fossil fuel combustion and/or soils related to changing agricultural practices in North America and Europe. Over the same time period, Antarctic ice cores show no such trend in δ15N. This would be consistent with previous work suggesting that biomass burning and/or stratospheric intrusion of NOx produced from N2O oxidation are dominant sources for nitrate formation at high southern latitudes. In comparison to the polar records, nitrate in tropical ice cores should represent more significant inputs from lightning, microbial processes in soils, and biomass burning. This may be reflected in new results from a high-elevation site in the Peruvian Andes that shows strong seasonal δ15N cycles of up to 15% (vs. N2). We compare and contrast these records in an effort to evaluate the contribution of NOx sources to nitrate over

  17. A methodology to determine boundary conditions from forced convection experiments using liquid crystal thermography

    NASA Astrophysics Data System (ADS)

    Jakkareddy, Pradeep S.; Balaji, C.

    2017-02-01

    This paper reports the results of an experimental study to estimate the heat flux and convective heat transfer coefficient using liquid crystal thermography and Bayesian inference in a heat generating sphere, enclosed in a cubical Teflon block. The geometry considered for the experiments comprises a heater inserted in a hollow hemispherical aluminium ball, resulting in a volumetric heat generation source that is placed at the center of the Teflon block. Calibrated thermochromic liquid crystal sheets are used to capture the temperature distribution at the front face of the Teflon block. The forward model is the three dimensional conduction equation which is solved within the Teflon block to obtain steady state temperatures, using COMSOL. Match up experiments are carried out for various velocities by minimizing the residual between TLC and simulated temperatures for every assumed loss coefficient, to obtain a correlation of average Nusselt number against Reynolds number. This is used for prescribing the boundary condition for the solution to the forward model. A surrogate model obtained by artificial neural network built upon the data from COMSOL simulations is used to drive a Markov Chain Monte Carlo based Metropolis Hastings algorithm to generate the samples. Bayesian inference is adopted to solve the inverse problem for determination of heat flux and heat transfer coefficient from the measured temperature field. Point estimates of the posterior like the mean, maximum a posteriori and standard deviation of the retrieved heat flux and convective heat transfer coefficient are reported. Additionally the effect of number of samples on the performance of the estimation process has been investigated.

  18. Estimation of spatially varying heat transfer coefficient from a flat plate with flush mounted heat sources using Bayesian inference

    NASA Astrophysics Data System (ADS)

    Jakkareddy, Pradeep S.; Balaji, C.

    2016-09-01

    This paper employs the Bayesian based Metropolis Hasting - Markov Chain Monte Carlo algorithm to solve inverse heat transfer problem of determining the spatially varying heat transfer coefficient from a flat plate with flush mounted discrete heat sources with measured temperatures at the bottom of the plate. The Nusselt number is assumed to be of the form Nu = aReb(x/l)c . To input reasonable values of ’a’ and ‘b’ into the inverse problem, first limited two dimensional conjugate convection simulations were done with Comsol. Based on the guidance from this different values of ‘a’ and ‘b’ are input to a computationally less complex problem of conjugate conduction in the flat plate (15mm thickness) and temperature distributions at the bottom of the plate which is a more convenient location for measuring the temperatures without disturbing the flow were obtained. Since the goal of this work is to demonstrate the eficiacy of the Bayesian approach to accurately retrieve ‘a’ and ‘b’, numerically generated temperatures with known values of ‘a’ and ‘b’ are treated as ‘surrogate’ experimental data. The inverse problem is then solved by repeatedly using the forward solutions together with the MH-MCMC aprroach. To speed up the estimation, the forward model is replaced by an artificial neural network. The mean, maximum-a-posteriori and standard deviation of the estimated parameters ‘a’ and ‘b’ are reported. The robustness of the proposed method is examined, by synthetically adding noise to the temperatures.

  19. Bayesian network reconstruction using systems genetics data: comparison of MCMC methods.

    PubMed

    Tasaki, Shinya; Sauerwine, Ben; Hoff, Bruce; Toyoshiba, Hiroyoshi; Gaiteri, Chris; Chaibub Neto, Elias

    2015-04-01

    Reconstructing biological networks using high-throughput technologies has the potential to produce condition-specific interactomes. But are these reconstructed networks a reliable source of biological interactions? Do some network inference methods offer dramatically improved performance on certain types of networks? To facilitate the use of network inference methods in systems biology, we report a large-scale simulation study comparing the ability of Markov chain Monte Carlo (MCMC) samplers to reverse engineer Bayesian networks. The MCMC samplers we investigated included foundational and state-of-the-art Metropolis-Hastings and Gibbs sampling approaches, as well as novel samplers we have designed. To enable a comprehensive comparison, we simulated gene expression and genetics data from known network structures under a range of biologically plausible scenarios. We examine the overall quality of network inference via different methods, as well as how their performance is affected by network characteristics. Our simulations reveal that network size, edge density, and strength of gene-to-gene signaling are major parameters that differentiate the performance of various samplers. Specifically, more recent samplers including our novel methods outperform traditional samplers for highly interconnected large networks with strong gene-to-gene signaling. Our newly developed samplers show comparable or superior performance to the top existing methods. Moreover, this performance gain is strongest in networks with biologically oriented topology, which indicates that our novel samplers are suitable for inferring biological networks. The performance of MCMC samplers in this simulation framework can guide the choice of methods for network reconstruction using systems genetics data.

  20. Characterization of muscle epimysium, perimysium and endomysium collagens.

    PubMed Central

    Light, N; Champion, A E

    1984-01-01

    In the past it has been proven difficult to separate and characterize collagen from muscle because of its relative paucity in this tissue. The present report presents a comprehensive methodology, combining methods previously described by McCollester [(1962) Biochim. Biophys. Acta 57, 427-437] and Laurent, Cockerill, McAnulty & Hastings [(1981) Anal. Biochem. 113, 301-312], in which the three major tracts of muscle connective tissue, the epimysium, perimysium and endomysium, may be prepared and separated from the bulk of muscle protein. Connective tissue thus prepared may be washed with salt and treated with pepsin to liberate soluble native collagen, or can be washed with sodium dodecyl sulphate to produce a very clean insoluble collagenous product. This latter type of preparation may be used for quantification of the ratio of the major genetic forms of collagen or for measurement of reducible cross-link content to give reproducible results. It was shown that both the epimysium and perimysium contain type I collagen as the major component and type III collagen as a minor component; perimysium also contained traces of type V collagen. The endomysium, the sheaths of individual muscle fibres, was shown to contain both type I and type III collagen as major components. Type V collagen was also present in small amounts, and type IV collagen, the collagenous component of basement membranes, was purified from endomysial preparations. This is the first biochemical demonstration of the presence of type IV collagen in muscle endomysium. The preparation was shown to be very similar to other type IV collagens from other basement membranes on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis and was indistinguishable from EHS sarcoma collagen and placenta type IV collagen in the electron microscope after rotary shadowing. Images Fig. 1. Fig. 2. Fig. 3. Fig. 4. PMID:6743238

  1. Assessment of Flood Disaster Impacts in Cambodia: Implications for Rapid Disaster Response

    NASA Astrophysics Data System (ADS)

    Ahamed, Aakash; Bolten, John; Doyle, Colin

    2016-04-01

    Disaster monitoring systems can provide near real time estimates of population and infrastructure affected by sudden onset natural hazards. This information is useful to decision makers allocating lifesaving resources following disaster events. Floods are the world's most common and devastating disasters (UN, 2004; Doocy et al., 2013), and are particularly frequent and severe in the developing countries of Southeast Asia (Long and Trong, 2001; Jonkman, 2005; Kahn, 2005; Stromberg, 2007; Kirsch et al., 2012). Climate change, a strong regional monsoon, and widespread hydropower construction contribute to a complex and unpredictable regional hydrodynamic regime. As such, there is a critical need for novel techniques to assess flood impacts to population and infrastructure with haste during and following flood events in order to enable governments and agencies to optimize response efforts following disasters. Here, we build on methods to determine regional flood extent in near real time and develop systems that automatically quantify the socioeconomic impacts of flooding in Cambodia. Software developed on cloud based, distributed processing Geographic Information Systems (GIS) is used to demonstrate spatial and numerical estimates of population, households, roadways, schools, hospitals, airports, agriculture and fish catch affected by severe monsoon flooding occurring in the Cambodian portion of Lower Mekong River Basin in 2011. Results show modest agreement with government and agency estimates. Maps and statistics generated from the system are intended to complement on the ground efforts and bridge information gaps to decision makers. The system is open source, flexible, and can be applied to other disasters (e.g. earthquakes, droughts, landslides) in various geographic regions.

  2. Quasiparticle explanation of the weak-thermalization regime under quench in a nonintegrable quantum spin chain

    NASA Astrophysics Data System (ADS)

    Lin, Cheng-Ju; Motrunich, Olexei I.

    2017-02-01

    The eigenstate thermalization hypothesis provides one picture of thermalization in a quantum system by looking at individual eigenstates. However, it is also important to consider how local observables reach equilibrium values dynamically. Quench protocol is one of the settings to study such questions. A recent numerical study [Bañuls, Cirac, and Hastings, Phys. Rev. Lett. 106, 050405 (2007), 10.1103/PhysRevLett.106.050405] of a nonintegrable quantum Ising model with longitudinal field under such a quench setting found different behaviors for different initial quantum states. One particular case called the "weak-thermalization" regime showed apparently persistent oscillations of some observables. Here we provide an explanation of such oscillations. We note that the corresponding initial state has low energy density relative to the ground state of the model. We then use perturbation theory near the ground state and identify the oscillation frequency as essentially a quasiparticle gap. With this quasiparticle picture, we can then address the long-time behavior of the oscillations. Upon making additional approximations which intuitively should only make thermalization weaker, we argue that the oscillations nevertheless decay in the long-time limit. As part of our arguments, we also consider a quench from a BEC to a hard-core boson model in one dimension. We find that the expectation value of a single-boson creation operator oscillates but decays exponentially in time, while a pair-boson creation operator has oscillations with a t-3 /2 decay in time. We also study dependence of the decay time on the density of bosons in the low-density regime and use this to estimate decay time for oscillations in the original spin model.

  3. [A Low-temperature Manganese Chloride Tetrahydrate Improves the Image Quality of Magnetic Resonance Cholangiopancreatography].

    PubMed

    Watanabe, Kunihiro; Ishimori, Yoshiyuki; Sakurai, Hitoshi; Iwai, Yuji; Miida, Kazuo; Kurita, Kouki

    2016-04-01

    Manganese chloride tetrahydrate (MCT) is one of the oral negative contrast agents which is indispensable for imaging of magnetic resonance cholangiopancreatography (MRCP). In this study, improvement of the image quality of MRCP by using low-temperature MCT is verified. All MR imagings were performed using 1.5 T scanner. The T(1) and T(2) values of the different temperature MCTs were measured in the phantom study. Different concentrations of MCT-doped water (30%, 50%, 70%, and 90%) were measured at several temperature conditions (10°C, 15°C, 23°C, 35°C, and 40°C). As a result, the T(1) and T(2) values became larger with a temperature rise. It was more remarkable in low-concentration MCT. Then, 17 healthy subjects were scanned two times with different temperatures of MCT. The MCT of the normal temperature (23°C) and low temperature (10°C) were taken at consecutive 2 days. The contrast between the stomach and the spleen were significantly higher in 2D half Fourier acquisition single shot turbo spin echo (HASTE) images by use of the low-temperature MCT. The contrast between the common bile duct and the adjacent background were significantly higher in the source images of 3D MRCP by use of the low temperature MCT. In addition, 76% of subjects answered in the questionnaire that the low temperature MCT is easier to drink. The low temperature MCT improves the image quality of MRCP and contributes to performing noninvasive examination.

  4. Planning and implementing an honors degree in environmental science curricula: a case study from the University of Delaware, USA

    NASA Astrophysics Data System (ADS)

    Levia, Delphis

    2015-04-01

    advisory Environmental Council include Drs. Delphis Levia (Program Director & Chair), Nancy Targett (Dean), Frank Newton, Tracy Deliberty, Steve Hastings, John Madsen, Paul Imhoff, Jan Johnson, Jerry Kauffman, Murray Johnston.

  5. A methodology to determine boundary conditions from forced convection experiments using liquid crystal thermography

    NASA Astrophysics Data System (ADS)

    Jakkareddy, Pradeep S.; Balaji, C.

    2016-05-01

    This paper reports the results of an experimental study to estimate the heat flux and convective heat transfer coefficient using liquid crystal thermography and Bayesian inference in a heat generating sphere, enclosed in a cubical Teflon block. The geometry considered for the experiments comprises a heater inserted in a hollow hemispherical aluminium ball, resulting in a volumetric heat generation source that is placed at the center of the Teflon block. Calibrated thermochromic liquid crystal sheets are used to capture the temperature distribution at the front face of the Teflon block. The forward model is the three dimensional conduction equation which is solved within the Teflon block to obtain steady state temperatures, using COMSOL. Match up experiments are carried out for various velocities by minimizing the residual between TLC and simulated temperatures for every assumed loss coefficient, to obtain a correlation of average Nusselt number against Reynolds number. This is used for prescribing the boundary condition for the solution to the forward model. A surrogate model obtained by artificial neural network built upon the data from COMSOL simulations is used to drive a Markov Chain Monte Carlo based Metropolis Hastings algorithm to generate the samples. Bayesian inference is adopted to solve the inverse problem for determination of heat flux and heat transfer coefficient from the measured temperature field. Point estimates of the posterior like the mean, maximum a posteriori and standard deviation of the retrieved heat flux and convective heat transfer coefficient are reported. Additionally the effect of number of samples on the performance of the estimation process has been investigated.

  6. Extracting and Applying SV-SV Shear Modes from Vertical Vibrator Data Across Geothermal Prospects Final Report

    SciTech Connect

    Hardage, Bob

    2013-07-01

    This 3-year project was terminated at the end of Year 1 because the DOE Geothermal project-evaluation committee decided one Milestone was not met and also concluded that our technology would not be successful. The Review Panel recommended a ?no-go? decision be implemented by DOE. The Principal Investigator and his research team disagreed with the conclusions reached by the DOE evaluation committee and wrote a scientifically based rebuttal to the erroneous claims made by the evaluators. We were not told if our arguments were presented to the people who evaluated our work and made the ?no-go? decision. Whatever the case regarding the information we supplied in rebuttal, we received an official letter from Laura Merrick, Contracting Officer at the Golden Field Office, dated June 11, 2013 in which we were informed that project funding would cease and instructed us to prepare a final report before September 5, 2013. In spite of the rebuttal arguments we presented to DOE, this official letter repeated the conclusions of the Review Panel that we had already proven to be incorrect. This is the final report that we are expected to deliver. The theme of this report will be another rebuttal of the technical deficiencies claimed by the DOE Geothermal Review Panel about the value and accomplishments of the work we did in Phase 1 of the project. The material in this report will present images made from direct-S modes produced by vertical-force sources using the software and research findings we developed in Phase 1 that the DOE Review Panel said would not be successful. We made these images in great haste when we were informed that DOE Geothermal rejected our rebuttal arguments and still regarded our technical work to be substandard. We thought it was more important to respond quickly rather than to take additional time to create better quality images than what we present in this Final Report.

  7. Predicting the global warming potential of agro-ecosystems in Europe

    NASA Astrophysics Data System (ADS)

    Lehuger, S.; Gabrielle, B.; Chaumartin, F.

    2009-04-01

    Nitrous oxide, carbon dioxide and methane are the main biogenic greenhouse gases contributing to the global warming potential (GWP) of agro-ecosystems. Evaluating the impact of agriculture on climate requires a capacity to predict the net exchanges of these gases in an integrated manner, as related to pedo-climatic conditions and crop management. The biophysical crop model CERES-EGC is designed to predict the productivity and GWP of agro-ecosystems at the plot-scale. Here we applied a Bayesian calibration to its both sub-models of N2O emissions and CO2 fluxes to deal with parameterization and uncertainty analysis. The N2O emission module of CERES-EGC was calibrated against chamber measurements from 7 arable sites in France and the CO2 flux module was calibrated against eddy-covariance measurements from 3 sites in Europe. Measurements from the various sites were assimilated in the posterior probability density functions for the different parameters, using a Bayesian calibration method based on the Metropolis-Hastings algorithm. The model was subsequently extrapolated to predict CO2 and N2O fluxes over entire crop rotations of 3 European experimental sites of the NitroEurope-IP network. Indirect GHG emissions arising from the production of agricultural inputs and from cropping operations were also added to the final GWP. Such modelling approach makes it possible to test various agronomic management scenarios, in order to design productive agro-ecosystems with low global warming potential. The model would be extrapolated from plot- to regional-scale, with the ultimate goal of generating spatialized GHG inventories. Differentiating the emissions in space would thus make it possible to target critical zones in mitigation scenarios at regional scale.

  8. A BAYESIAN HIERARCHICAL SPATIAL MODEL FOR DENTAL CARIES ASSESSMENT USING NON-GAUSSIAN MARKOV RANDOM FIELDS

    PubMed Central

    Jin, Ick Hoon; Yuan, Ying; Bandyopadhyay, Dipankar

    2016-01-01

    Research in dental caries generates data with two levels of hierarchy: that of a tooth overall and that of the different surfaces of the tooth. The outcomes often exhibit spatial referencing among neighboring teeth and surfaces, i.e., the disease status of a tooth or surface might be influenced by the status of a set of proximal teeth/surfaces. Assessments of dental caries (tooth decay) at the tooth level yield binary outcomes indicating the presence/absence of teeth, and trinary outcomes at the surface level indicating healthy, decayed, or filled surfaces. The presence of these mixed discrete responses complicates the data analysis under a unified framework. To mitigate complications, we develop a Bayesian two-level hierarchical model under suitable (spatial) Markov random field assumptions that accommodates the natural hierarchy within the mixed responses. At the first level, we utilize an autologistic model to accommodate the spatial dependence for the tooth-level binary outcomes. For the second level and conditioned on a tooth being non-missing, we utilize a Potts model to accommodate the spatial referencing for the surface-level trinary outcomes. The regression models at both levels were controlled for plausible covariates (risk factors) of caries, and remain connected through shared parameters. To tackle the computational challenges in our Bayesian estimation scheme caused due to the doubly-intractable normalizing constant, we employ a double Metropolis-Hastings sampler. We compare and contrast our model performances to the standard non-spatial (naive) model using a small simulation study, and illustrate via an application to a clinical dataset on dental caries. PMID:27807470

  9. Uncertainty in dual permeability model parameters for structured soils

    NASA Astrophysics Data System (ADS)

    Arora, B.; Mohanty, B. P.; McGuire, J. T.

    2012-01-01

    Successful application of dual permeability models (DPM) to predict contaminant transport is contingent upon measured or inversely estimated soil hydraulic and solute transport parameters. The difficulty in unique identification of parameters for the additional macropore- and matrix-macropore interface regions, and knowledge about requisite experimental data for DPM has not been resolved to date. Therefore, this study quantifies uncertainty in dual permeability model parameters of experimental soil columns with different macropore distributions (single macropore, and low- and high-density multiple macropores). Uncertainty evaluation is conducted using adaptive Markov chain Monte Carlo (AMCMC) and conventional Metropolis-Hastings (MH) algorithms while assuming 10 out of 17 parameters to be uncertain or random. Results indicate that AMCMC resolves parameter correlations and exhibits fast convergence for all DPM parameters while MH displays large posterior correlations for various parameters. This study demonstrates that the choice of parameter sampling algorithms is paramount in obtaining unique DPM parameters when information on covariance structure is lacking, or else additional information on parameter correlations must be supplied to resolve the problem of equifinality of DPM parameters. This study also highlights the placement and significance of matrix-macropore interface in flow experiments of soil columns with different macropore densities. Histograms for certain soil hydraulic parameters display tri-modal characteristics implying that macropores are drained first followed by the interface region and then by pores of the matrix domain in drainage experiments. Results indicate that hydraulic properties and behavior of the matrix-macropore interface is not only a function of saturated hydraulic conductivity of the macroporematrix interface (Ksa) and macropore tortuosity (lf) but also of other parameters of the matrix and macropore domains.

  10. Bayesian inversion of marine controlled source electromagnetic data offshore Vancouver Island, Canada

    NASA Astrophysics Data System (ADS)

    Gehrmann, Romina A. S.; Schwalenberg, Katrin; Riedel, Michael; Spence, George D.; Spieß, Volkhard; Dosso, Stan E.

    2016-01-01

    This paper applies nonlinear Bayesian inversion to marine controlled source electromagnetic (CSEM) data collected near two sites of the Integrated Ocean Drilling Program (IODP) Expedition 311 on the northern Cascadia Margin to investigate subseafloor resistivity structure related to gas hydrate deposits and cold vents. The Cascadia margin, off the west coast of Vancouver Island, Canada, has a large accretionary prism where sediments are under pressure due to convergent plate boundary tectonics. Gas hydrate deposits and cold vent structures have previously been investigated by various geophysical methods and seabed drilling. Here, we invert time-domain CSEM data collected at Sites U1328 and U1329 of IODP Expedition 311 using Bayesian methods to derive subsurface resistivity model parameters and uncertainties. The Bayesian information criterion is applied to determine the amount of structure (number of layers in a depth-dependent model) that can be resolved by the data. The parameter space is sampled with the Metropolis-Hastings algorithm in principal-component space, utilizing parallel tempering to ensure wider and efficient sampling and convergence. Nonlinear inversion allows analysis of uncertain acquisition parameters such as time delays between receiver and transmitter clocks as well as input electrical current amplitude. Marginalizing over these instrument parameters in the inversion accounts for their contribution to the geophysical model uncertainties. One-dimensional inversion of time-domain CSEM data collected at measurement sites along a survey line allows interpretation of the subsurface resistivity structure. The data sets can be generally explained by models with 1 to 3 layers. Inversion results at U1329, at the landward edge of the gas hydrate stability zone, indicate a sediment unconformity as well as potential cold vents which were previously unknown. The resistivities generally increase upslope due to sediment erosion along the slope. Inversion

  11. A method to reduce the rejection rate in Monte Carlo Markov chains

    NASA Astrophysics Data System (ADS)

    Baldassi, Carlo

    2017-03-01

    We present a method for Monte Carlo sampling on systems with discrete variables (focusing in the Ising case), introducing a prior on the candidate moves in a Metropolis–Hastings scheme which can significantly reduce the rejection rate, called the reduced-rejection-rate (RRR) method. The method employs same probability distribution for the choice of the moves as rejection-free schemes such as the method proposed by Bortz, Kalos and Lebowitz (BKL) (1975 J. Comput. Phys. 17 10–8) however, it uses it as a prior in an otherwise standard Metropolis scheme: it is thus not fully rejection-free, but in a wide range of scenarios it is nearly so. This allows to extend the method to cases for which rejection-free schemes become inefficient, in particular when the graph connectivity is not sparse, but the energy can nevertheless be expressed as a sum of two components, one of which is computed on a sparse graph and dominates the measure. As examples of such instances, we demonstrate that the method yields excellent results when performing Monte Carlo simulations of quantum spin models in presence of a transverse field in the Suzuki–Trotter formalism, and when exploring the so-called robust ensemble which was recently introduced in Baldassi et al (2016 Proc. Natl Acad. Sci. 113 E7655–62). Our code for the Ising case is publicly available (RRR Monte Carlo code https://github.com/carlobaldassi/RRRMC.jl), and extensible to user-defined models: it provides efficient implementations of standard Metropolis, the RRR method, the BKL method (extended to the case of continuous energy specra), and the waiting time method by Dall and Sibani (2001 Comput. Phys. Commun. 141 260–7).

  12. An Introduction to Thinking about Trustworthy Research into the Genetics of Intelligence.

    PubMed

    Parens, Erik; Appelbaum, Paul S

    2015-01-01

    The advent of new technologies has rekindled some hopes that it will be possible to identify genetic variants that will help to explain why individuals are different with respect to complex traits. At least one leader in the development of "whole genome sequencing"-the Chinese company BGI-has been quite public about its commitment to using the technique to investigate the genetics of intelligence in general and high intelligence in particular. Because one needs large samples to detect the small effects associated with small genetic differences in the sequence of those base pairs, to make headway with the new sequencing technologies, one also needs to enlist much larger numbers of study participants than geneticists have enrolled before. In an effort to increase the size of a sample, one team of researchers approached the Center for Talented Youth at Johns Hopkins University. They wanted to gain access to records concerning participants in CTY's ongoing Study of Exceptional Talent, and they wanted to approach those individuals to see if they would be willing to share samples of their DNA. We agreed that CTY's dilemma about whether to give the researchers access to those records raised larger questions about the ethics of research into the genetics of intelligence, and we decided to hold a workshop at The Hastings Center that could examine those questions. Our purpose was to create what, borrowing from Sarah Richardson, we came to call a "transformative conversation" about research into the genetics of general cognitive ability-a conversation that would take a wide and long view and would involve a diverse group of stakeholders, including both people who have been highly critical of the research and people who engage in it. This collection of essays, which grew out of that workshop, is intended to provide an introduction to and exploration of this complex and important area.

  13. Reproducibility and accuracy of optic nerve sheath diameter assessment using ultrasound compared to magnetic resonance imaging

    PubMed Central

    2013-01-01

    Background Quantification of the optic nerve sheath diameter (ONSD) by transbulbar sonography is a promising non-invasive technique for the detection of altered intracranial pressure. In order to establish this method as follow-up tool in diseases with intracranial hyper- or hypotension scan-rescan reproducibility and accuracy need to be systematically investigated. Methods The right ONSD of 15 healthy volunteers (mean age 24.5 ± 0.8 years) were measured by both transbulbar sonography (9 – 3 MHz) and 3 Tesla MRI (half-Fourier acquisition single-shot turbo spin-echo sequences, HASTE) 3 and 5 mm behind papilla. All volunteers underwent repeated ultrasound and MRI examinations in order to assess scan-rescan reproducibility and accuracy. Moreover, inter- and intra-observer variabilities were calculated for both techniques. Results Scan-rescan reproducibility was robust for ONSD quantification by sonography and MRI at both depths (r > 0.75, p ≤ 0.001, mean differences < 2%). Comparing ultrasound- and MRI-derived ONSD values, we found acceptable agreement between both methods for measurements at a depth of 3 mm (r = 0.72, p = 0.002, mean difference < 5%). Further analyses revealed good inter- and intra-observer reliability for sonographic measurements 3 mm behind the papilla and for MRI at 3 and 5 mm (r > 0.82, p < 0.001, mean differences < 5%). Conclusions Sonographic ONSD quantification 3 mm behind the papilla can be performed with good reproducibility, measurement accuracy and observer agreement. Thus, our findings emphasize the feasibility of this technique as a non-invasive bedside tool for longitudinal ONSD measurements. PMID:24289136

  14. Firefighter safety: rampant unsafe practices as documented in mainstream media.

    PubMed

    Kahn, Steven A; Woods, Jason; Sipes, Jan C; Toscano, Nicole; Bell, Derek E

    2014-01-01

    More than 30,000 firefighters are injured on the fireground each year. Literature suggests that injury often occurs when protective gear is not used properly. According to firefighters, failure to correctly wear protective equipment occurs for several reasons: (1) gear not used because of haste, (2) cumbersome gear can sometimes interfere with performance, and (3) cultural factors. The purpose of this study is to quantify improper gear and tactic use in a publicly available, online video repository in order to better understand unsafe firefighting. This was an Institutional Review Board-exempt study of public video records. A search for "fire fighting videos" was conducted at YouTube (www.youtube.com). The first 50 videos that contained volunteer or career firefighters at work fighting fires were selected evaluated for appropriate use of personal protective equipment and for safe behavior. The videos were evaluated by two highly experienced professional firefighters. Of the 50 videos reviewed, 25 (50%) demonstrated violations of firefighting safety principles. Of the unsafe videos, 21 (42%) displayed firefighters improperly using gear, while the other 4 (8%) were related to unsound tactics. The most common problem was failure to wear or properly secure a self-contained breathing apparatus when appropriate (14 videos or 28%). The second most common failure was lack of helmet, hood, or approved gloves (11 videos or 22%). In conclusion, firefighting as documented on YouTube is often unsafe because of failure to properly use personal protective equipment. Half of the videos reviewed contained unsafe practices. With such a shockingly high rate of unsafe firefighting, the profession is in need of additional education and reform. In response to this epidemic, a multidisciplinary educational program has been developed to improve firefighter awareness of gear limitations and burn injury risk. Effectiveness of educational programs should be documented in additional

  15. Bayesian Atmospheric Radiative Transfer (BART): Model, Statistics Driver, and Application to HD 209458b

    NASA Astrophysics Data System (ADS)

    Cubillos, Patricio; Harrington, Joseph; Blecic, Jasmina; Stemm, Madison M.; Lust, Nate B.; Foster, Andrew S.; Rojo, Patricio M.; Loredo, Thomas J.

    2014-11-01

    Multi-wavelength secondary-eclipse and transit depths probe the thermo-chemical properties of exoplanets. In recent years, several research groups have developed retrieval codes to analyze the existing data and study the prospects of future facilities. However, the scientific community has limited access to these packages. Here we premiere the open-source Bayesian Atmospheric Radiative Transfer (BART) code. We discuss the key aspects of the radiative-transfer algorithm and the statistical package. The radiation code includes line databases for all HITRAN molecules, high-temperature H2O, TiO, and VO, and includes a preprocessor for adding additional line databases without recompiling the radiation code. Collision-induced absorption lines are available for H2-H2 and H2-He. The parameterized thermal and molecular abundance profiles can be modified arbitrarily without recompilation. The generated spectra are integrated over arbitrary bandpasses for comparison to data. BART's statistical package, Multi-core Markov-chain Monte Carlo (MC3), is a general-purpose MCMC module. MC3 implements the Differental-evolution Markov-chain Monte Carlo algorithm (ter Braak 2006, 2009). MC3 converges 20-400 times faster than the usual Metropolis-Hastings MCMC algorithm, and in addition uses the Message Passing Interface (MPI) to parallelize the MCMC chains. We apply the BART retrieval code to the HD 209458b data set to estimate the planet's temperature profile and molecular abundances. This work was supported by NASA Planetary Atmospheres grant NNX12AI69G and NASA Astrophysics Data Analysis Program grant NNX13AF38G. JB holds a NASA Earth and Space Science Fellowship.

  16. Duality in Phase Space and Complex Dynamics of an Integrated Pest Management Network Model

    NASA Astrophysics Data System (ADS)

    Yuan, Baoyin; Tang, Sanyi; Cheke, Robert A.

    Fragmented habitat patches between which plants and animals can disperse can be modeled as networks with varying degrees of connectivity. A predator-prey model with network structures is proposed for integrated pest management (IPM) with impulsive control actions. The model was analyzed using numerical methods to investigate how factors such as the impulsive period, the releasing constant of natural enemies and the mode of connections between the patches affect pest outbreak patterns and the success or failure of pest control. The concept of the cluster as defined by Holland and Hastings is used to describe variations in results ranging from global synchrony when all patches have identical fluctuations to n-cluster solutions with all patches having different dynamics. Heterogeneity in the initial densities of either pest or natural enemy generally resulted in a variety of cluster oscillations. Surprisingly, if n > 1, the clusters fall into two groups one with low amplitude fluctuations and the other with high amplitude fluctuations (i.e. duality in phase space), implying that control actions radically alter the system's characteristics by inducing duality and more complex dynamics. When the impulsive period is small enough, i.e. the control strategy is undertaken frequently, the pest can be eradicated. As the period increases, the pest's dynamics shift from a steady state to become chaotic with periodic windows and more multicluster oscillations arise for heterogenous initial density distributions. Period-doubling bifurcation and periodic halving cascades occur as the releasing constant of the natural enemy increases. For the same ecological system with five differently connected networks, as the randomness of the connectedness increases, the transient duration becomes smaller and the probability of multicluster oscillations appearing becomes higher.

  17. Segmentation of polycystic kidneys from MR images

    NASA Astrophysics Data System (ADS)

    Racimora, Dimitri; Vivier, Pierre-Hugues; Chandarana, Hersh; Rusinek, Henry

    2010-03-01

    Polycystic kidney disease (PKD) is a disorder characterized by the growth of numerous fluid filled cysts in the kidneys. Measuring cystic kidney volume is thus crucial to monitoring the evolution of the disease. While T2-weighted MRI delineates the organ, automatic segmentation is very difficult due to highly variable shape and image contrast. The interactive stereology methods used currently involve a compromise between segmentation accuracy and time. We have investigated semi-automated methods: active contours and a sub-voxel morphology based algorithm. Coronal T2- weighted images of 17 patients were acquired in four breath-holds using the HASTE sequence on a 1.5 Tesla MRI unit. The segmentation results were compared to ground truth kidney masks obtained as a consensus of experts. Automatic active contour algorithm yielded an average 22% +/- 8.6% volume error. A recently developed method (Bridge Burner) based on thresholding and constrained morphology failed to separate PKD from the spleen, yielding 37.4% +/- 8.7% volume error. Manual post-editing reduced the volume error to 3.2% +/- 0.8% for active contours and 3.2% +/- 0.6% for Bridge Burner. The total time (automated algorithm plus editing) was 15 min +/- 5 min for active contours and 19 min +/- 11 min for Bridge Burner. The average volume errors for stereology method were 5.9%, 6.2%, 5.4% for mesh size 6.6, 11, 16.5 mm. The average processing times were 17, 7, 4 min. These results show that nearly two-fold improvement in PKD segmentation accuracy over stereology technique can be achieved with a combination of active contours and postediting.

  18. Using Satellite Measurements of Surface Soil Moisture to Improve Estimates of CO2 and CH4 from Peatlands

    NASA Astrophysics Data System (ADS)

    MacBean, N.; Disney, M.; Gomez-Dans, J.; Lewis, P.; Ineson, P.

    2010-12-01

    Peatlands are important stores of carbon through the partial decomposition of organic matter. However peatlands not only sequester CO2 but they are the main natural source of methane (CH4) due to anaerobic microbial activity under waterlogged conditions. Northern wetlands contribute about 35TgCH4yr-1 [1]. The uncertainty on this estimate is large (from 1mgCH4 m-2 y-1 to 2200mgCH4 m-2 y-1), therefore there is a need to better quantify CH4 emissions and their role in the net carbon balance of peatlands. A correct representation of the hydrology of the system is necessary for modelling CH4 flux as the water table depth controls the area where methanogenic bacteria are active. One of the key variables in the calculation of water table depth is the soil moisture. Soil moisture also affects the decomposition rates of carbon in the soil and influences the water and energy fluxes at the land surface - atmosphere boundary. Microwave measurements of surface soil moisture from satellites can theoretically be used to improve estimates predicted by models. Results from an Observing System Simulation Experiment (OSSE), designed to investigate how observations from satellites may be able to constrain modelled carbon fluxes, are presented. An adapted version of the Carnegie-Ames-Stanford Approach (CASA) model [2] is used that includes a representation of methane dynamics [3]. Synthetic satellite observations of soil moisture are used to update model estimates using a Metropolis Hastings Markov Chain Monte Carlo (MCMC) approach. The effect of temporal frequency and spacing, and precision of observations, is examined with a view to establishing the set of observations that would make a significant improvement in model uncertainty. The results are compared with the system characteristics of existing satellite soil moisture measurements. We believe this is the first attempt to assimilate surface soil moisture into an ecosystem model that includes a full representation of CH4 flux.

  19. Excitable scale free networks

    NASA Astrophysics Data System (ADS)

    Copelli, M.; Campos, P. R. A.

    2007-04-01

    When a simple excitable system is continuously stimulated by a Poissonian external source, the response function (mean activity versus stimulus rate) generally shows a linear saturating shape. This is experimentally verified in some classes of sensory neurons, which accordingly present a small dynamic range (defined as the interval of stimulus intensity which can be appropriately coded by the mean activity of the excitable element), usually about one or two decades only. The brain, on the other hand, can handle a significantly broader range of stimulus intensity, and a collective phenomenon involving the interaction among excitable neurons has been suggested to account for the enhancement of the dynamic range. Since the role of the pattern of such interactions is still unclear, here we investigate the performance of a scale-free (SF) network topology in this dynamic range problem. Specifically, we study the transfer function of disordered SF networks of excitable Greenberg-Hastings cellular automata. We observe that the dynamic range is maximum when the coupling among the elements is critical, corroborating a general reasoning recently proposed. Although the maximum dynamic range yielded by general SF networks is slightly worse than that of random networks, for special SF networks which lack loops the enhancement of the dynamic range can be dramatic, reaching nearly five decades. In order to understand the role of loops on the transfer function we propose a simple model in which the density of loops in the network can be gradually increased, and show that this is accompanied by a gradual decrease of dynamic range.

  20. Nest-site selection in the acorn woodpecker

    USGS Publications Warehouse

    Hooge, P.N.; Stanback, M.T.; Koenig, Walter D.

    1999-01-01

    Acorn Woodpeckers (Melanerpes formicivorus) at Hastings Reservation in central California prefer to nest in dead limbs in large, dead valley oaks (Quercus lobata) and California sycamores (Platanus racemosa) that are also frequently used as acorn storage trees. Based on 232 nest cavities used over an 18-year period, we tested whether preferred or modal nest-site characters were associated with increased reproductive success (the 'nest-site quality' hypothesis). We also examined whether more successful nests were likely to experience more favorable microclimatic conditions or to be less accessible to terrestrial predators. We found only equivocal support for the nest-site quality hypothesis: only 1 of 5 preferred characters and 2 of 10 characters exhibiting a clear modality were correlated with higher reproductive success. All three characteristics of nests known or likely to be associated with a more favorable microclimate, and two of five characteristics likely to render nests less accessible to predators, were correlated with higher reproductive success: These results suggest that nest cavities in this population are built in part to take advantage of favorable microclimatic conditions and, to a lesser extent, to reduce access to predators. However, despite benefits of particular nest characteristics, birds frequently nested in apparently suboptimal cavities. We also found a significant relationship between mean group size and the history of occupancy of particular territories and the probability of nest cavities being built in microclimatically favorable live limbs, suggesting that larger groups residing on more stable territories were better able to construct nests with optimal characteristics. This indicates that there may be demographic, as well as ecological, constraints on nest-site selection in this primary cavity nester.

  1. Bayesian model selection validates a biokinetic model for zirconium processing in humans

    PubMed Central

    2012-01-01

    Background In radiation protection, biokinetic models for zirconium processing are of crucial importance in dose estimation and further risk analysis for humans exposed to this radioactive substance. They provide limiting values of detrimental effects and build the basis for applications in internal dosimetry, the prediction for radioactive zirconium retention in various organs as well as retrospective dosimetry. Multi-compartmental models are the tool of choice for simulating the processing of zirconium. Although easily interpretable, determining the exact compartment structure and interaction mechanisms is generally daunting. In the context of observing the dynamics of multiple compartments, Bayesian methods provide efficient tools for model inference and selection. Results We are the first to apply a Markov chain Monte Carlo approach to compute Bayes factors for the evaluation of two competing models for zirconium processing in the human body after ingestion. Based on in vivo measurements of human plasma and urine levels we were able to show that a recently published model is superior to the standard model of the International Commission on Radiological Protection. The Bayes factors were estimated by means of the numerically stable thermodynamic integration in combination with a recently developed copula-based Metropolis-Hastings sampler. Conclusions In contrast to the standard model the novel model predicts lower accretion of zirconium in bones. This results in lower levels of noxious doses for exposed individuals. Moreover, the Bayesian approach allows for retrospective dose assessment, including credible intervals for the initially ingested zirconium, in a significantly more reliable fashion than previously possible. All methods presented here are readily applicable to many modeling tasks in systems biology. PMID:22863152

  2. Quantum dot transport in soil, plants, and insects.

    PubMed

    Al-Salim, Najeh; Barraclough, Emma; Burgess, Elisabeth; Clothier, Brent; Deurer, Markus; Green, Steve; Malone, Louise; Weir, Graham

    2011-08-01

    Environmental risk assessment of nanomaterials requires information not only on their toxicity to non-target organisms, but also on their potential exposure pathways. Here we report on the transport and fate of quantum dots (QDs) in the total environment: from soils, through their uptake into plants, to their passage through insects following ingestion. Our QDs are nanoparticles with an average particle size of 6.5 nm. Breakthrough curves obtained with CdTe/mercaptopropionic acid QDs applied to columns of top soil from a New Zealand organic apple orchard, a Hastings silt loam, showed there to be preferential flow through the soil's macropores. Yet the effluent recovery of QDs was just 60%, even after several pore volumes, indicating that about 40% of the influent QDs were filtered and retained by the soil column via some unknown exchange/adsorption/sequestration mechanism. Glycine-, mercaptosuccinic acid-, cysteine-, and amine-conjugated CdSe/ZnS QDs were visibly transported to a limited extent in the vasculature of ryegrass (Lolium perenne), onion (Allium cepa) and chrysanthemum (Chrysanthemum sp.) plants when cut stems were placed in aqueous QD solutions. However, they were not seen to be taken up at all by rooted whole plants of ryegrass, onion, or Arabidopsis thaliana placed in these solutions. Leafroller (Lepidoptera: Tortricidae) larvae fed with these QDs for two or four days, showed fluorescence along the entire gut, in their frass (larval feces), and, at a lower intensity, in their haemolymph. Fluorescent QDs were also observed and elevated cadmium levels detected inside the bodies of adult moths that had been fed QDs as larvae. These results suggest that exposure scenarios for QDs in the total environment could be quite complex and variable in each environmental domain.

  3. Frequency of Nerve Root Sleeve Cysts in Autosomal Dominant Polycystic Kidney Disease

    PubMed Central

    Aşık, Murat; Tufan, Fatih; Akpınar, Timur Selçuk; Akalın, Nilgül; Ceyhan, Elvan; Tunç, Necmeddin; Hasıloğlu, Zehra Işık; Altıparmak, Mehmet Rıza; Ecder, Tevfik; Albayram, Sait

    2016-01-01

    Background There is sporadic data about the occurrence of spinal meningeal cysts in patients with autosomal dominant polycystic kidney disease (ADPKD). We suggest that there is a relationship with the frequency and size of spinal meningeal cysts and headache, intracranial aneurysms, and cerebrospinal fluid leakage in patients with ADPKD. Aim To investigate the relationship with spinal meningeal cyst, cerebrospinal fluid leakage, and headache in patients with ADPKD. Study Design Cross-sectional study. Methods We enrolled 50 patients with ADPKD and 37 healthy volunteers. This cross-sectional study included patients with ADPKD and matched healthy volunteers. Magnetic resonance imaging myelography was performed using the 3D-T2 HASTE technique in an MRI scanner. We questioned our subjects regarding presence of headache and evaluated headache severity using a visual analog scale. The relationship between the number and size of spinal meningeal cysts with headache, intracranial aneurysms, and liver cysts was also investigated. Results Spinal meningeal cysts were more numerous and larger in patients than in controls (14.8±11.6 vs. 6.4±4.6 cysts respectively, p<0.001, 68.3±49.3 vs. 25.4±20.1 mm, p<0.001, respectively). Spinal cyst number and size were similar in APDKD patients with or without intracranial aneurysms. Headache score was correlated with the size and number of spinal meningeal cysts. This was valid only in patients with ADPKD. Conclusion Abnormality involving the vessel wall in ADPKD may explain the increased number of spinal meningeal cysts in ADPKD. Moreover, leakage of cerebrospinal fluid secondary to spinal meningeal cyst may be responsible for recurrent severe headache by causing spontaneous intracranial hypotension in these patients. PMID:27994919

  4. MAP estimators for piecewise continuous inversion

    NASA Astrophysics Data System (ADS)

    Dunlop, M. M.; Stuart, A. M.

    2016-10-01

    We study the inverse problem of estimating a field u a from data comprising a finite set of nonlinear functionals of u a , subject to additive noise; we denote this observed data by y. Our interest is in the reconstruction of piecewise continuous fields u a in which the discontinuity set is described by a finite number of geometric parameters a. Natural applications include groundwater flow and electrical impedance tomography. We take a Bayesian approach, placing a prior distribution on u a and determining the conditional distribution on u a given the data y. It is then natural to study maximum a posterior (MAP) estimators. Recently (Dashti et al 2013 Inverse Problems 29 095017) it has been shown that MAP estimators can be characterised as minimisers of a generalised Onsager-Machlup functional, in the case where the prior measure is a Gaussian random field. We extend this theory to a more general class of prior distributions which allows for piecewise continuous fields. Specifically, the prior field is assumed to be piecewise Gaussian with random interfaces between the different Gaussians defined by a finite number of parameters. We also make connections with recent work on MAP estimators for linear problems and possibly non-Gaussian priors (Helin and Burger 2015 Inverse Problems 31 085009) which employs the notion of Fomin derivative. In showing applicability of our theory we focus on the groundwater flow and EIT models, though the theory holds more generally. Numerical experiments are implemented for the groundwater flow model, demonstrating the feasibility of determining MAP estimators for these piecewise continuous models, but also that the geometric formulation can lead to multiple nearby (local) MAP estimators. We relate these MAP estimators to the behaviour of output from MCMC samples of the posterior, obtained using a state-of-the-art function space Metropolis-Hastings method.

  5. The efficiency of Gd-EOB-DTPA-enhanced magnetic resonance cholangiography in living donor liver transplantation: a preliminary study.

    PubMed

    Ogul, Hayri; Kantarci, Mecit; Pirimoglu, Berhan; Karaca, Leyla; Aydinli, Bulent; Okur, Aylin; Ozturk, Gurkan; Kizrak, Yesim

    2014-03-01

    The aim of this study was to evaluate utility of gadoxetic acid disodium (Gd-EOB-DTPA)-enhanced magnetic resonance cholangiography (MRC) for the detection of biliary complications after living donor liver transplantation (LDLT). A total of 18 patients with suspected biliary complications underwent MRC. T2-weighted MRC and contrast-enhanced MRC (CE-MRC) were used to identify the biliary complications. MRC included routine breath-hold T2-weighted MRC using half-Fourier acquisition single-shot turbo spin-echo (HASTE) sequences and Gd-EOB-DTPA-enhanced MRC T1-weighted volumetric interpolated breath-hold examination (VIBE) sequences. Before confirming the biliary complications, one observer reviewed the MRC images and the CE-MRC images separately. The verification procedures and MRC findings were compared, and the sensitivity, specificity, and accuracy of both techniques were calculated for the identification of biliary complications. The observer found six of seven biliary complications using CE-MRC. The sensitivity was 85.7% and the accuracy was 94.4%. Using MRC alone, sensitivity was 57.1% and accuracy was 55.5%. The accuracy of Gd-EOB-DTPA-enhanced MRC was superior to MRC in locating biliary leaks (p < 0.05). The usage of Gd-EOB-DTPA-enhanced MRC yields information that complements the MRC findings that improve the identification of biliary complications. We recommend the use of MRC in addition to Gd-EOB-DTPA-enhanced MRC to increase the preoperative accuracy when assessing the biliary complications after LDLT.

  6. Relative role of parameter vs. climate uncertainty for predictions of future Southeastern U.S. pine carbon cycling

    NASA Astrophysics Data System (ADS)

    Jersild, A.; Thomas, R. Q.; Brooks, E.; Teskey, R. O.; Wynne, R. H.; Arthur, D.; Gonzalez, C.; Thomas, V. A.; Fox, T. D.; Smallman, L.

    2015-12-01

    Predictions of the how forest productivity and carbon sequestration will respond to climate change are essential for assisting land managers in adapting to future climate. However, current predictions can include considerable uncertainty that is often not well quantified. To address the need for better quantification of uncertainty, we calculated and compared parameter and climate prediction uncertainty for predictions of Southeastern U.S. pine forest productivity. We used a Metropolis-Hastings Markov Chain Monte Carlo-based data assimilation technique to fuse regionally widespread and diverse datasets with the Physiological Principles Predicting Growth model (3PG) model. The datasets incorporated include biomass observations from forest research plots that are part of the Pine Integrated Network: Education, Mitigation, and Adaptation project (PINEMAP) project, photosynthesis and evaporation observations from loblolly pine Ameriflux sites, and productivity responses to elevated CO2 from the Duke Free Air C site. These spatially and temporally diverse data sets give our unique analysis a more accurately measured uncertainty by constraining complimentary components of the model. In our analysis, parameter uncertainty was quantified using simulations that integrate across the posterior parameter distributions, while climate model uncertainty was quantified using downscaled RCP 8.5 simulations from twenty different CMIP5 climate models. Overall, we found that the uncertainty in future productivity of Southeastern U.S. managed pine forests that was associated with parameterization is comparable to the uncertainty associated with climate simulations. Our results indicate that reducing parameterization in ecosystem model development can improve future predictions of forest productivity and carbon sequestration, but uncertainties in future climate predictions also need to be properly quantified and communicated to forest owners and managers.

  7. An implementation of differential evolution algorithm for inversion of geoelectrical data

    NASA Astrophysics Data System (ADS)

    Balkaya, Çağlayan

    2013-11-01

    Differential evolution (DE), a population-based evolutionary algorithm (EA) has been implemented to invert self-potential (SP) and vertical electrical sounding (VES) data sets. The algorithm uses three operators including mutation, crossover and selection similar to genetic algorithm (GA). Mutation is the most important operator for the success of DE. Three commonly used mutation strategies including DE/best/1 (strategy 1), DE/rand/1 (strategy 2) and DE/rand-to-best/1 (strategy 3) were applied together with a binomial type crossover. Evolution cycle of DE was realized without boundary constraints. For the test studies performed with SP data, in addition to both noise-free and noisy synthetic data sets two field data sets observed over the sulfide ore body in the Malachite mine (Colorado) and over the ore bodies in the Neem-Ka Thana cooper belt (India) were considered. VES test studies were carried out using synthetically produced resistivity data representing a three-layered earth model and a field data set example from Gökçeada (Turkey), which displays a seawater infiltration problem. Mutation strategies mentioned above were also extensively tested on both synthetic and field data sets in consideration. Of these, strategy 1 was found to be the most effective strategy for the parameter estimation by providing less computational cost together with a good accuracy. The solutions obtained by DE for the synthetic cases of SP were quite consistent with particle swarm optimization (PSO) which is a more widely used population-based optimization algorithm than DE in geophysics. Estimated parameters of SP and VES data were also compared with those obtained from Metropolis-Hastings (M-H) sampling algorithm based on simulated annealing (SA) without cooling to clarify uncertainties in the solutions. Comparison to the M-H algorithm shows that DE performs a fast approximate posterior sampling for the case of low-dimensional inverse geophysical problems.

  8. Uncertainty Estimation of Shear-wave Velocity Structure from Bayesian Inversion of Microtremor Array Dispersion Data

    NASA Astrophysics Data System (ADS)

    Dosso, S. E.; Molnar, S.; Cassidy, J.

    2010-12-01

    Bayesian inversion of microtremor array dispersion data is applied, with evaluation of data errors and model parameterization, to produce the most-probable shear-wave velocity (VS) profile together with quantitative uncertainty estimates. Generally, the most important property characterizing earthquake site response is the subsurface VS structure. The microtremor array method determines phase velocity dispersion of Rayleigh surface waves from multi-instrument recordings of urban noise. Inversion of dispersion curves for VS structure is a non-unique and nonlinear problem such that meaningful evaluation of confidence intervals is required. Quantitative uncertainty estimation requires not only a nonlinear inversion approach that samples models proportional to their probability, but also rigorous estimation of the data error statistics and an appropriate model parameterization. A Bayesian formulation represents the solution of the inverse problem in terms of the posterior probability density (PPD) of the geophysical model parameters. Markov-chain Monte Carlo methods are used with an efficient implementation of Metropolis-Hastings sampling to provide an unbiased sample from the PPD to compute parameter uncertainties and inter-relationships. Nonparametric estimation of a data error covariance matrix from residual analysis is applied with rigorous a posteriori statistical tests to validate the covariance estimate and the assumption of a Gaussian error distribution. The most appropriate model parameterization is determined using the Bayesian information criterion (BIC), which provides the simplest model consistent with the resolving power of the data. Parameter uncertainties are found to be under-estimated when data error correlations are neglected and when compressional-wave velocity and/or density (nuisance) parameters are fixed in the inversion. Bayesian inversion of microtremor array data is applied at two sites in British Columbia, the area of highest seismic risk in

  9. Bayesian inversion of microtremor array dispersion data in southwestern British Columbia

    NASA Astrophysics Data System (ADS)

    Molnar, Sheri; Dosso, Stan E.; Cassidy, John F.

    2010-11-01

    This paper applies Bayesian inversion, with evaluation of data errors and model parametrization, to produce the most-probable shear-wave velocity profile together with quantitative uncertainty estimates from microtremor array dispersion data. Generally, the most important property for characterizing earthquake site response is the shear-wave velocity (VS) profile. The microtremor array method determines phase velocity dispersion of Rayleigh surface waves from multi-instrument recordings of urban noise. Inversion of dispersion curves for VS structure is a non-unique and non-linear problem such that meaningful evaluation of confidence intervals is required. Quantitative uncertainty estimation requires not only a non-linear inversion approach that samples models proportional to their probability, but also rigorous estimation of the data error statistics and an appropriate model parametrization. This paper applies a Bayesian formulation that represents the solution of the inverse problem in terms of the posterior probability density (PPD) of the geophysical model parameters. Markov-chain Monte Carlo methods are used with an efficient implementation of Metropolis-Hastings sampling to provide an unbiased sample from the PPD to compute parameter uncertainties and inter-relationships. Nonparametric estimation of a data error covariance matrix from residual analysis is applied with rigorous a posteriori statistical tests to validate the covariance estimate and the assumption of a Gaussian error distribution. The most appropriate model parametrization is determined using the Bayesian information criterion, which provides the simplest model consistent with the resolving power of the data. Parametrizations considered vary in the number of layers, and include layers with uniform, linear and power-law gradients. Parameter uncertainties are found to be underestimated when data error correlations are neglected and when compressional-wave velocity and/or density (nuisance

  10. Adding a Second Ku-Band Antenna to the International Space Station

    NASA Technical Reports Server (NTRS)

    DuSold, Chuck; Thacker, Corey; Kwatra, Sundeep

    2011-01-01

    The International Space Station, as originally developed, used the Ku-Band Tracking and Data Relay Satellite System communications link to transmit non-critical data to the ground. Since becoming operational, the use for the link evolved to include additional services that, although also not critical, were deemed to be necessary for the crew. The external Ku-Band Antennas were designed for transport to the ISS in the shuttle cargo bay and thus are not suitable for manifesting on any current cargo vehicle. The original intent was to stow two spare antennas on orbit in a protective container until such time as they were needed to replace a failing unit which is a long and complicated process due to the complexity of the removal and replacement procedure. The Boeing Company proposed manifesting one of those spare antennas in an operable configuration eliminating the need for an Extravehicular Activity (EVA) to correct the first failure and as such minimizing the time to hours rather than weeks required to restore the Ku-Band communications link after failures. After the first failure, an EVA would be scheduled to replace the failed antenna with the stowed spare antenna. Because the hot spare is activated internal to the ISS, the replacement of the failed unit can be done when convenient rather than in haste. This paper describes the methodology used to locate a suitable site to add a new antenna mast to the ISS as well the process followed to fabricate, deliver and install the new interface hardware. Because this was not planned when the ISS was originally designed, structural, power, data and Intermediate Frequency signal connections had to be found for use. With the movement of the P6 solar array element from the initial location in the center zenith location of the ISS to the end of the port side of the truss and concurrent relocation of one string of S-Band communications assets, there were candidate power, data and structural connections available on the Z1 Truss

  11. Determining Quasar Black Hole Mass Functions from their Broad Emission Lines: Application to the Bright Quasar Survey

    NASA Astrophysics Data System (ADS)

    Kelly, Brandon C.; Vestergaard, Marianne; Fan, Xiaohui

    2009-02-01

    We describe a Bayesian approach to estimating quasar black hole mass functions (BHMF) using the broad emission lines to estimate black hole mass. We show how using the broad-line mass estimates in combination with statistical techniques developed for luminosity function estimation (e.g., the 1/Va correction) leads to statistically biased results. We derive the likelihood function for the BHMF based on the broad-line mass estimates, and derive the posterior distribution for the BHMF, given the observed data. We develop our statistical approach for a flexible model where the BHMF is modeled as a mixture of Gaussian functions. Statistical inference is performed using Markov chain Monte Carlo (MCMC) methods, and we describe a Metropolis-Hastings algorithm to perform the MCMC. The MCMC simulates random draws from the probability distribution of the BHMF parameters, given the data, and we use a simulated data set to show how these random draws may be used to estimate the probability distribution for the BHMF. In addition, we show how the MCMC output may be used to estimate the probability distribution of any quantities derived from the BHMF, such as the peak in the space density of quasars. Our method has the advantage that it is able to constrain the BHMF even beyond the survey detection limits at the adopted confidence level, accounts for measurement errors and the intrinsic uncertainty in broad-line mass estimates, and provides a natural way of estimating the probability distribution of any quantities derived from the BHMF. We conclude by using our method to estimate the local active BHMF using the z < 0.5 Bright Quasar Survey sources. At z ~ 0.2, the quasar BHMF falls off approximately as a power law with slope ~2 for M BH gsim 108 M sun. Our analysis implies that at a given M BH, z < 0.5 broad-line quasars have a typical Eddington ratio of ~0.4 and a dispersion in Eddington ratio of lsim0.5 dex.

  12. Ionized calcium in normal serum, ultrafiltrates, and whole blood determined by ion-exchange electrodes

    PubMed Central

    Moore, Edward W.

    1970-01-01

    Ion-exchange calcium electrodes represent the first practical method for the direct measurement of ionized calcium [Ca++] in biologic fluids. Using both “static” and “flow-through” electrodes, serum [Ca++] was within a rather narrow range: 0.94-1.33 mmoles/liter (mean, 1.14 mmoles/liter). Within a given individual, [Ca++] varied only about 6% over a several month period. Consistent pH effects on [Ca++] were observed in serum and whole blood, [Ca++] varying inversely with pH. Less consistent pH effects were also noted in ultrafiltrates, believed to largely represent precipitation of certain calcium complexes from a supersaturated solution. Heparinized whole blood [Ca++] was significantly less than in corresponding serum at normal blood pH, related to the formation of a calcium-heparin complex. [Ca++] in ultrafiltrates represented a variable fraction (66.7-90.2%) of total diffusible calcium. There was no apparent correlation between serum ionized and total calcium concentrations. Thus, neither serum total calcium nor total ultrafiltrable calcium provided a reliable index of serum [Ca++]. Change in serum total calcium was almost totally accounted for by corresponding change in protein-bound calcium [CaProt]. About 81% of [CaProt] was estimated to be bound to albumin and about 19% to globulins. From observed pH, serum protein, and [CaProt] data, a nomogram was developed for estimating [CaProt] without ultrafiltration. Data presented elsewhere indicate that calcium binding by serum proteins obeys the mass-law equation for a monoligand association. This was indicated in the present studies by a close correspondence of observed serum [Ca++] values with those predicted by the McLean-Hastings nomogram. While these electrodes allow study of numerous problems not possible previously, they have not been perfected to the same degree of reliability obtainable with current pH electrodes. The commercial (Orion flow-through) electrode is: (a) expensive. (b) requires

  13. Estimating methane fluxes at a landscape scale

    NASA Astrophysics Data System (ADS)

    Stockdale, James; MacBean, Natasha

    2010-05-01

    Terrestrial methane fluxes are an important component of peatland carbon budgets. Using a well-studied peatland site in Wales as a case study, we present a variety of approaches to quantifying annual methane fluxes at a landscape scale, with a focus on the comparison between a simple stratification method, an empirical regression-based method and a process-based method. The simplest approach relies on in situ methane flux measurements which, due to the indirect effects on methane flux from the vascular transport mechanism and co-variation with hydrological conditions, were stratified by vegetation type. Aside from this initial classification, an annual landscape flux was produced through a linear scaling model without attempting to consider any physical, chemical or biological processes known to control methane fluxes. The regression-based approach attempted to model fluxes using repeated measurements from across the study site over a 12 months period, together with environmental variables from associated locations. This method classifies the landscape by vegetation in a similar way to the first method and also takes into consideration variables commonly known to influence methane flux such as temperature and water table. However, no direct consideration of methane production or consumption is included in this empirical regression model. In contrast to both the preceding methods, estimates of methane flux using a process-based model were constructed for the same landscape. This method uses the Carnegie-Ames-Stanford Approach (CASA) model (Potter et al., 1993), which has been modified to include a representation of methane dynamics. The model is calibrated with ground-based measurements of net CH4 flux and water table depth using a Metropolis Hastings Markov Chain Monte Carlo approach. Comparison of these approaches shows that, while simple methods of stratification and scaling are computationally inexpensive and quick to perform, they are least successful when

  14. On the Tracy-Widomβ Distribution for β=6

    NASA Astrophysics Data System (ADS)

    Grava, Tamara; Its, Alexander; Kapaev, Andrei; Mezzadri, Francesco

    2016-11-01

    We study the Tracy-Widom distribution function for Dyson's β-ensemble with β = 6. The starting point of our analysis is the recent work of I. Rumanov where he produces a Lax-pair representation for the Bloemendal-Virág equation. The latter is a linear PDE which describes the Tracy-Widom functions corresponding to general values of β. Using his Lax pair, Rumanov derives an explicit formula for the Tracy-Widom β=6 function in terms of the second Painlevé transcendent and the solution of an auxiliary ODE. Rumanov also shows that this formula allows him to derive formally the asymptotic expansion of the Tracy-Widom function. Our goal is to make Rumanov's approach and hence the asymptotic analysis it provides rigorous. In this paper, the first one in a sequel, we show that Rumanov's Lax-pair can be interpreted as a certain gauge transformation of the standard Lax pair for the second Painlevé equation. This gauge transformation though contains functional parameters which are defined via some auxiliary nonlinear ODE which is equivalent to the auxiliary ODE of Rumanov's formula. The gauge-interpretation of Rumanov's Lax-pair allows us to highlight the steps of the original Rumanov's method which needs rigorous justifications in order to make the method complete. We provide a rigorous justification of one of these steps. Namely, we prove that the Painlevé function involved in Rumanov's formula is indeed, as it has been suggested by Rumanov, the Hastings-McLeod solution of the second Painlevé equation. The key issue which we also discuss and which is still open is the question of integrability of the auxiliary ODE in Rumanov's formula. We note that this question is crucial for the rigorous asymptotic analysis of the Tracy-Widom function. We also notice that our work is a partial answer to one of the problems related to the β-ensembles formulated by Percy Deift during the June 2015 Montreal Conference on integrable systems.

  15. The environment of ageing.

    PubMed Central

    Tinker, A

    1997-01-01

    The issue of housing and the wider environment for an ageing population is one where there are many unanswered questions. In this paper a number of key issues are discussed and for each of these the focus is on three aspects. These are the current situation, its reasonableness and what research is needed in order to make decisions about policy and practice. The first three issues relate to the profile of older people themselves and the importance of home to them. The changing profile of older people is not just about an ageing population but also about the growing prominence of those with dementia, women, people from black and ethnic minority groups and one person households, yet little is known about the type of housing which should be provided. Of equal concern is the widening gap between those with a high standard of living (including housing) and those with a low standard of living. The importance of home to older people means that research must focus on how people can be enabled to remain there, and also on the costs, financial and otherwise, to carers and to society. The next three issues relate to the type of housing older people live in and moves in later life. The startling change in the tenure pattern with a growth of owner occupation brings problems as does the decline in social housing. The advantages and disadvantages of the different types of housing--mainstream and specialized--for older people are relatively well known. However the balance between the two needs more research as does that on retirement communities. While it is well known that there are peaks of migration in old age and that moves are often made in haste, little is known about the process of decision making. The final two topics concern links between housing and other aspects of older people's lives. On health more research is needed on temperature, mortality and morbidity, homelessness and accidents and especially on links between services. These topics have implications for planning

  16. Vestibular system paresis due to emergency endovascular catheterization.

    PubMed

    Simoceli, Lucinda; Sguillar, Danilo Anunciatto; Santos, Henrique Mendes Paiva; Caputti, Camilla

    2012-04-01

    Objetivo: O objetivo deste relato de caso é descrever uma causa incomum de vestibulopatia periférica associada à perda auditiva unilateral em paciente idoso pós- cateterismo de urgência.Relato de caso: Paciente do gênero masculino, 82 anos, submetido à correção de aneurisma roto de aorta abdominal, no intra-operatório sofreu infarto agudo do miocárdio necessitando de angioplastia primária. Após alta hospitalar refere queixa de hipoacusia acentuada à direita e vertigem incapacitante, sem sinais neurológicos focais. Ao exame clínico otorrinolaringológico apresentava: Teste de Weber lateralizado para a esquerda, nistagmo espontâneo para a esquerda , marcha oscilante, leve disbasia e ataxia, índex-nariz e diadococinesia normais, Teste de Romberg com oscilação sem queda e Fukuda com desvio lateral para a direita. O exame audiométrico evidenciava anacusia à direita e perda neurossensorial à esquerda em agudos, arreflexia vestibular à direita na prova calórica e, na tomografia computadorizada dos ossos temporais e tronco-encefálico, presença de haste metálica atravessando o osso temporal direito, a partir da veia jugular interna e bulbo jugular, atravessando os canais semicirculares posterior, superior e vestíbulo, projetando-se em lobo temporal. O diagnóstico radiológico foi lesão traumática por guia endovascular metálico durante cateterismo de urgência e a conduta, considerando que o paciente não havia compensado o equilíbrio, foi reabilitação vestibular.Conclusão: Queixas de tontura no paciente idoso devem ser criteriosamente avaliadas diante do seu histórico clínico patológico pois os antecedentes de doenças e tratamentos prévios, em geral, direcionam as hipóteses diagnósticas porém podem trazer alterações inesperadas.

  17. Reconciling conceptualizations of relationships and person-centred care for older people with cognitive impairment in acute care settings.

    PubMed

    Rushton, Carole; Edvardsson, David

    2017-02-10

    Relationships are central to enacting person-centred care of the older person with cognitive impairment. A fuller understanding of relationships and the role they play facilitating wellness and preserving personhood is critical if we are to unleash the productive potential of nursing research and person-centred care. In this article, we target the acute care setting because much of the work about relationships and older people with cognitive impairment has tended to focus on relationships in long-term care. The acute care setting is characterized by archetypal constraints which differentiate it from long-term care, in terms of acuity and haste, task-orientated work patterns and influence from "the rule of medicine," all of which can privilege particular types of relating. In this article, we drew on existing conceptualizations of relationships from theory and practice by tapping in to the intellectual resources provided by nurse researchers, the philosophy of Martin Buber and ANT scholars. This involved recounting two examples of dyadic and networked relationships which were re-interpreted using two complementary theoretical approaches to provide deeper and more comprehensive conceptualizations of these relationships. By re-presenting key tenets from the work of key scholars on the topic relationships, we hope to hasten socialization of these ideas into nursing into the acute care setting. First, by enabling nurses to reflect on how they might work toward cultivating relationships that are more salutogenic and consistent with the preservation of personhood. Second, by stimulating two distinct but related lines of research enquiry which focus on dyadic and networked relationships with the older person with cognitive impairment in the acute care setting. We also hope to reconcile the schism that has emerged in the literature between preferred approaches to care of the older person with cognitive impairment, that is person-centred care versus relationship-centred care

  18. A Methodology for Post Operational Clean Out of a Highly Active Facility Including Solids Behaviour - 12386

    SciTech Connect

    Edmondson, Michael J.; Ward, Tracy R.; Maxwell, Lisa J.

    2012-07-01

    The Highly Active Liquor Evaporation and Storage (HALES) plant at Sellafield handles acidic fission product containing liquor with typical activities of the order of 18x10{sup 9} Bq/ml. A strategy experimental feedback approach has been used to establish a wash regime for the Post Operational Clean Out (POCO) of the oldest storage tanks for this liquor. Two different wash reagents have been identified as being potentially suitable for removal of acid insoluble fission product precipitates. Ammonium carbamate and sodium carbonate yield similar products during the proposed wash cycle. The proposed wash reagents provide dissolution of caesium phosphomolybdate (CPM) and zirconium molybdate (ZM) solid phases but yields a fine, mobile precipitate of metal carbonates from the Highly Active Liquor (HAL) supernate. Addition of nitric acid to the wash effluent can cause CPM to precipitate where there is sufficient caesium and phosphorous available. Where they are not present (from ZM dissolution) the nitric acid addition initially produces a nitrate precipitate which then re-dissolves, along with the metal carbonates, to give a solid-free solution. The different behaviour of the two solids during the wash cycle has led to the proposal for an amended flowsheet. Additional studies on the potential to change the morphology of crystallising ZM have presented opportunities for changing the rheology of ZM sediments through doping with tellurium or particular organic acids. Two different wash reagents have been identified as being potentially suitable for the POCO of HALES Oldside HASTs. AC and SC both yield similar products during the proposed wash cycle. However, the different behaviour of the two principle HAL solids, CPM and ZM, during the wash cycle has led to the proposal for an amended flowsheet. Additional studies on the potential to change the morphology of crystallising ZM have presented opportunities for changing its rheology through doping with tellurium or certain

  19. Improving carbon model phenology using data assimilation

    NASA Astrophysics Data System (ADS)

    Exrayat, Jean-François; Smallman, T. Luke; Bloom, A. Anthony; Williams, Mathew

    2015-04-01

    Carbon cycle dynamics is significantly impacted by ecosystem phenology, leading to substantial seasonal and inter-annual variation in the global carbon balance. Representing inter-annual variability is key for predicting the response of the terrestrial ecosystem to climate change and disturbance. Existing terrestrial ecosystem models (TEMs) often struggle to accurately simulate observed inter-annual variability. TEMs often use different phenological models based on plant functional type (PFT) assumptions. Moreover, due to a high level of computational overhead in TEMs they are unable to take advantage of globally available datasets to calibrate their models. Here we describe the novel CARbon DAta MOdel fraMework (CARDAMOM) for data assimilation. CARDAMOM is used to calibrate the Data Assimilation Linked Ecosystem Carbon version 2 (DALEC2) model using Bayes' Theorem within a Metropolis Hastings - Markov Chain Monte Carlo (MH-MCMC). CARDAMOM provides a framework which combines knowledge from observations, such as remotely sensed LAI, and heuristic information in the form of Ecological and Dynamical Constraints (EDCs). The EDCs are representative of real world processes and constrain parameter interdependencies and constrain carbon dynamics. We used CARDAMOM to bring together globally spanning datasets of LAI and the DALEC2 and DALEC2-GSI models. These analyses allow us to investigate the sensitivity ecosystem processes to the representation of phenology. DALEC2 uses an analytically solved model of phenology which is invariant between years. In contrast DALEC2-GSI uses a growing season index (GSI) calculated as a function of temperature, vapour pressure deficit (VPD) and photoperiod to calculate bud-burst and leaf senescence, allowing the model to simulate inter-annual variability in response to climate. Neither model makes any PFT assumptions about the phenological controls of a given ecosystem, allowing the data alone to determine the impact of the meteorological

  20. Degradation monitoring using probabilistic inference

    NASA Astrophysics Data System (ADS)

    Alpay, Bulent

    In order to increase safety and improve economy and performance in a nuclear power plant (NPP), the source and extent of component degradations should be identified before failures and breakdowns occur. It is also crucial for the next generation of NPPs, which are designed to have a long core life and high fuel burnup to have a degradation monitoring system in order to keep the reactor in a safe state, to meet the designed reactor core lifetime and to optimize the scheduled maintenance. Model-based methods are based on determining the inconsistencies between the actual and expected behavior of the plant, and use these inconsistencies for detection and diagnostics of degradations. By defining degradation as a random abrupt change from the nominal to a constant degraded state of a component, we employed nonlinear filtering techniques based on state/parameter estimation. We utilized a Bayesian recursive estimation formulation in the sequential probabilistic inference framework and constructed a hidden Markov model to represent a general physical system. By addressing the problem of a filter's inability to estimate an abrupt change, which is called the oblivious filter problem in nonlinear extensions of Kalman filtering, and the sample impoverishment problem in particle filtering, we developed techniques to modify filtering algorithms by utilizing additional data sources to improve the filter's response to this problem. We utilized a reliability degradation database that can be constructed from plant specific operational experience and test and maintenance reports to generate proposal densities for probable degradation modes. These are used in a multiple hypothesis testing algorithm. We then test samples drawn from these proposal densities with the particle filtering estimates based on the Bayesian recursive estimation formulation with the Metropolis Hastings algorithm, which is a well-known Markov chain Monte Carlo method (MCMC). This multiple hypothesis testing

  1. [The analysis of patients with body traumas treated in the Military Medical Academy's Second Clinical Hospital of the Medical University of Lodz].

    PubMed

    Sikorski, Tomasz; Piotrowski, Dariusz; Gaszyński, Wojciech

    2011-01-01

    According to recent WHO reports, body traumas are ranked third with respect of frequency of occurrence right after cardiovascular diseases and tumours, and are considered one of the major medical problems. Trauma is a kind of energy (mechanical, thermal or chemical) affecting the human body. After crossing the threshold of tissue endurance, an injury or damage occurs. A common problem of all the centres that treat traumas is a reliable and comparable assessment of injury severity. Constant improvement of the trauma scores, contributes to increased objectivity of the assessment of injury severity and makes trauma research easier. To a large extent, commonness of the scores enables the exchange of experiences with respect to treating patients after trauma. An ideal scale should be reliable, easy to use, and most of all commonly used, thus enabling the employment of a common "traumatologic" language. In the following research, the test group was comprised of 137 adult patients including 113 men (82%) and 24 women (18%). Most patients were aged from 20 to 60 years, that is, in the productive age. Appropriate trauma treatment results in the reduction of the costs of hospitalisation time of those patients and their recovery. An accident or worse still death of a young person is not only a personal tragedy for the family. It is also a big economic loss for the society which results from "lost years of life" and thus "lost years of work". Quick and appropriate treatment, done in a proper centre with appropriately trained staff and highest quality equipment will allow not only to reduce the victim's suffering and return to their daily life, but also minimise the social costs connected with disability pensions, benefits and compensations. Most injuries happened at work--61% were probably due to haste but most of all not complying with occupational health and safety regulations, which all employees should know and comply with. It involves doctors writing a sick note for the

  2. Paleoseismology under sea: First evidence for irregular seismic cycles during Holocene off Algeria from turbidites

    NASA Astrophysics Data System (ADS)

    Ratzov, Gueorgui; Cattaneo, Antonio; Babonneau, Nathalie; Déverchere, Jacques; Yelles, Karim; Bracene, Rabah

    2013-04-01

    According to simple models, stress build-up along a given fault is proportional to the time elapsed since the previous earthquake. Although the resulting « seismic gap » hypothesis suits well for moderate magnitude earthquake (Mw 4-5), large events (Mw>6) are hardly predictable and show great variation in recurrence intervals. Thus, models based on stress transfer and interactions between faults suggest that an earthquake may haste or delay the occurrence of next earthquake on adjacent fault by increasing or lowering the level of static stress. Here, we show that meaningful information of large earthquakes recurrence intervals over several seismic cycles may be obtained using turbidite record offshore the Algerian margin (Mediterranean Sea), an area prone to relatively large (M~7) earthquakes in historical times. Indeed, as evidenced on the Cascadia subduction zone, synchroneous turbidites over a large area and originated from independent sources, are most likely triggered by an earthquake. To test the method on this slowly convergent margin, we analysed turbidites in 3 sediment cores collected off the area shaken by the 1980 Ms 7.3 El Asnam and 1954 M6.7 Orléansville earthquakes. We used X-ray radioscopy, XRF major elements counter, magnetic susceptibility, and grain-size distribution to accurately discriminate turbidites (~instantaneous deposit) from hemipelagites (continuous background sedimentation). We dated turbidites by calculating hemipelagic sedimentation rates obtained with AMS radiocarbon ages, and applied the rates between turbidites. Finally, the age of events was compared to the only paleoseismic investigation available onland. We found that 10 to 25 turbidites deposited as single or multiple pulses over the last ~8ka. Once correlated from site to site, they support 14 seismic events. Most events are correlated with the paleoseismic record of the El Asnam fault, but uncorrelated events support that other faults were active. Only the first of the

  3. Using eddy covariance of CO2, 13CO2 and CH4, continuous soil respiration measurements, and PhenoCams to constrain a process-based biogeochemical model for carbon market-funded wetland restoration

    NASA Astrophysics Data System (ADS)

    Oikawa, P. Y.; Baldocchi, D. D.; Knox, S. H.; Sturtevant, C. S.; Verfaillie, J. G.; Dronova, I.; Jenerette, D.; Poindexter, C.; Huang, Y. W.

    2015-12-01

    We use multiple data streams in a model-data fusion approach to reduce uncertainty in predicting CO2 and CH4 exchange in drained and flooded peatlands. Drained peatlands in the Sacramento-San Joaquin River Delta, California are a strong source of CO2 to the atmosphere and flooded peatlands or wetlands are a strong CO2 sink. However, wetlands are also large sources of CH4 that can offset the greenhouse gas mitigation potential of wetland restoration. Reducing uncertainty in model predictions of annual CO2 and CH4 budgets is critical for including wetland restoration in Cap-and-Trade programs. We have developed and parameterized the Peatland Ecosystem Photosynthesis, Respiration, and Methane Transport model (PEPRMT) in a drained agricultural peatland and a restored wetland. Both ecosystem respiration (Reco) and CH4 production are a function of 2 soil carbon (C) pools (i.e. recently-fixed C and soil organic C), temperature, and water table height. Photosynthesis is predicted using a light use efficiency model. To estimate parameters we use a Markov Chain Monte Carlo approach with an adaptive Metropolis-Hastings algorithm. Multiple data streams are used to constrain model parameters including eddy covariance of CO2, 13CO2 and CH4, continuous soil respiration measurements and digital photography. Digital photography is used to estimate leaf area index, an important input variable for the photosynthesis model. Soil respiration and 13CO2 fluxes allow partitioning of eddy covariance data between Reco and photosynthesis. Partitioned fluxes of CO2 with associated uncertainty are used to parametrize the Reco and photosynthesis models within PEPRMT. Overall, PEPRMT model performance is high. For example, we observe high data-model agreement between modeled and observed partitioned Reco (r2 = 0.68; slope = 1; RMSE = 0.59 g C-CO2 m-2 d-1). Model validation demonstrated the model's ability to accurately predict annual budgets of CO2 and CH4 in a wetland system (within 14% and 1

  4. Model-independent limits and constraints on extended theories of gravity from cosmic reconstruction techniques

    NASA Astrophysics Data System (ADS)

    de la Cruz-Dombriz, Álvaro; Dunsby, Peter K. S.; Luongo, Orlando; Reverberi, Lorenzo

    2016-12-01

    The onset of dark energy domination depends on the particular gravitational theory driving the cosmic evolution. Model independent techniques are crucial to test the both the present ΛCDM cosmological paradigm and alternative theories, making the least possible number of assumptions about the Universe. In this paper we investigate whether cosmography is able to distinguish between different gravitational theories, by determining bounds on model parameters for three different extensions of General Relativity, namely quintessence, F(𝒯) and f(R) gravitational theories. We expand each class of theories in powers of redshift z around the present time, making no additional assumptions. This procedure is an extension of previous work and can be seen as the most general approach for testing extended theories of gravity through the use of cosmography. In the case of F(𝒯) and f(R) theories, we show that some assumptions on model parameters often made in previous works are superfluous or even unjustified. We use data from the Union 2.1 supernovae catalogue, baryonic acoustic oscillation data and H(z) differential age compilations, which probe cosmology on different scales of the cosmological evolution. We perform a Monte Carlo analysis using a Metropolis-Hastings algorithm with a Gelman-Rubin convergence criterion, reporting 1-σ and 2-σ confidence levels. To do so, we perform two distinct fits, assuming only data within z < 1 first and then without limitations in redshift. We obtain the corresponding numerical intervals in which coefficients span, and find that the data is compatible the ΛCDM limit of all three theories at the 1-σ level, while still compatible with quite a large portion of parameter space. We compare our results to the truncated ΛCDM paradigm, demonstrating that our bounds divert from the expectations of previous works, showing that the permitted regions of coefficients are significantly modified and in general widened with respect to

  5. Effects of variable winds on biological productivity on continental shelves in coastal upwelling systems

    NASA Astrophysics Data System (ADS)

    Botsford, Louis W.; Lawrence, Cathryn A.; Dever, Edward P.; Hastings, Alan; Largier, John

    2006-12-01

    The production and distribution of biological material in wind-driven coastal upwelling systems are of global importance, yet they remain poorly understood. Production is frequently presumed to be proportional to upwelling rate, yet high winds can lead to advective losses from continental shelves, where many species at higher trophic levels reside. An idealized mixed-layer conveyor (MLC) model of biological production from constant upwelling winds demonstrated previously that the amount of new production available to shelf species increased with upwelling at low winds, but declined at high winds [Botsford, L.W., Lawrence, C.A., Dever, E.P., Hastings, A., Largier, J., 2003. Wind strength and biological productivity in upwelling systems: an idealized study. Fisheries Oceanography 12, 245-259]. Here we analyze the response of this model to time-varying winds for parameter values and observed winds from the Wind Events and Shelf Transport (WEST) study region. We compare this response to the conventional view that the results of upwelling are proportional to upwelled volume. Most new production per volume upwelled available to shelf species occurs following rapid increases in shelf transit time due to decreases in wind (i.e. relaxations). However, on synoptic, event time-scales shelf production is positively correlated with upwelling rate. This is primarily due to the effect of synchronous periods of low values in these time series, paradoxically due to wind relaxations. On inter-annual time-scales, computing model production from wind forcing from 20 previous years shows that these synchronous periods of low values have little effect on correlations between upwelling and production. Comparison of model production from 20 years of wind data over a range of shelf widths shows that upwelling rate will predict biological production well only in locations where cross-shelf transit times are greater than the time required for phytoplankton or zooplankton production. For

  6. CMA Announces the 1996 Responsible Care Catalyst Awards Winners

    NASA Astrophysics Data System (ADS)

    1996-06-01

    Eighteen exceptional teachers of science, chemical technology, chemistry, and chemical engineering have been selected to receive a Responsible Care Chemical Manufacturers Association's 1996 Catalyst Award. The Responsible Care Catalyst Awards Program honors individuals who have the ability to inspire students toward careers in chemistry and science-related fields through their excellent teaching ability in and out of the classroom. The program also seeks to draw public attention to the importance of quality chemistry and science teaching at the undergraduate level. Since the award was established in 1957, 502 teachers of science, chemistry, and chemical engineering have been honored. Winners are selected from a wide range of nominations submitted by colleagues, friends, and administrators. All pre-high school, high school, two and four-year college, or university teachers in the United States and Canada are eligible. Each award winner will be presented with a medal and citation. National award winners receive 5,000; regional award winners receive 2,500. National Winners. Martin N. Ackermann, Oberlin College, Oberlin, OH Kenneth R. Jolls, Iowa State University, Ames, IA Suzanne Zobrist Kelly, Warren H. Meeker Elementary School, Ames, IA John V. Kenkel, Southeast Community College, Lincoln, NE George C. Lisensky, Beloit College, Beloit, WI James M. McBride, Yale University, New Haven, CT Marie C. Sherman, Ursuline Academy, St. Louis, MO Dwight D. Sieggreen, Cooke Middle School, Northville, MI Regional Winners Two-Year College. East-Georgianna Whipple-VanPatter, Central Community College, Hastings, NE West-David N. Barkan, Northwest College, Powell, WY High School. East-John Hnatow, Jr., Emmaus High School, Northampton, PA South-Carole Bennett, Gaither High School, Tampa, FL Midwest-Kenneth J. Spengler, Palatine High School, Palatine, IL West-Ruth Rand, Albuquerque, Albuquerque, NM Middle School. East-Thomas P. Kelly, Grandville Public Schools, Grandville, NH

  7. Essentials in the diagnosis of acid-base disorders and their high altitude application.

    PubMed

    Paulev, P E; Zubieta-Calleja, G R

    2005-09-01

    This report describes the historical development in the clinical application of chemical variables for the interpretation of acid-base disturbances. The pH concept was already introduced in 1909. Following World War II, disagreements concerning the definition of acids and bases occurred, and since then two strategies have been competing. Danish scientists in 1923 defined an acid as a substance able to give off a proton at a given pH, and a base as a substance that could bind a proton, whereas the North American Singer-Hasting school in 1948 defined acids as strong non-buffer anions and bases as non-buffer cations. As a consequence of this last definition, electrolyte disturbances were mixed up with real acid-base disorders and the variable, strong ion difference (SID), was introduced as a measure of non-respiratory acid-base disturbances. However, the SID concept is only an empirical approximation. In contrast, the Astrup/Siggaard-Andersen school of scientists, using computer strategies and the Acid-base Chart, has made diagnosis of acid-base disorders possible at a glance on the Chart, when the data are considered in context with the clinical development. Siggaard-Andersen introduced Base Excess (BE) or Standard Base Excess (SBE) in the extracellular fluid volume (ECF), extended to include the red cell volume (eECF), as a measure of metabolic acid-base disturbances and recently replaced it by the term Concentration of Titratable Hydrogen Ion (ctH). These two concepts (SBE and ctH) represent the same concentration difference, but with opposite signs. Three charts modified from the Siggaard-Andersen Acid-Base Chart are presented for use at low, medium and high altitudes of 2500 m, 3500 m, and 4000 m, respectively. In this context, the authors suggest the use of Titratable Hydrogen Ion concentration Difference (THID) in the extended extracellular fluid volume, finding it efficient and better than any other determination of the metabolic component in acid

  8. Flow Dynamics and Sediment Entrainment in Natural Turbidity Currents Inferred from Numerical Modeling

    NASA Astrophysics Data System (ADS)

    Traer, M. M.; Hilley, G. E.; Fildani, A.

    2009-12-01

    Submarine turbidity currents derive their momentum from gravity acting upon the density contrast between sediment-laden and clear water, and so unlike fluvial systems, the dynamics of such flows are inextricably linked to the rates at which they deposit and entrain sediment. We have analyzed the sensitivity of the growth and maintenance of turbidity currents to sediment entrainment and deposition using the layer-averaged equations of conservation of fluid and sediment mass, and conservation of momentum and turbulent kinetic energy. Our model results show that the dynamics of turbidity currents are extremely sensitive to the functional form and empirical constants of the relationship between sediment entrainment and friction velocity. Data on the relationship between sediment entrainment and friction velocity for submarine density flows are few and as a result, entrainment formulations are populated with data from sub-aerial flows not driven by the density contrast between clear and turbid water. If we entertain the possibility that sediment entrainment in sub-aerial rivers is different than in dense underflows, flow parameters such as velocity, height, and concentration were found nearly impossible to predict beyond a few hundred meters based on the limited laboratory data available that constrain the sediment entrainment process in turbidity currents. The sensitivity of flow dynamics to the functional relationship between friction velocity and sediment entrainment indicates that independent calibration of a sediment entrainment law in the submarine environment is necessary to realistically predict the dynamics of these flows and the resulting patterns of erosion and deposition. To calibrate such a relationship, we have developed an inverse methodology that utilizes existing submarine channel morphology as a means of constraining the sediment entrainment function parameters. We use a Bayesian Metropolis-Hastings sampler to determine the sediment entrainment

  9. The Time Is Now: Bioethics and LGBT Issues.

    PubMed

    Powell, Tia; Foglia, Mary Beth

    2014-09-01

    Our goal in producing this special issue is to encourage our colleagues to incorporate topics related to LGBT populations into bioethics curricula and scholarship. Bioethics has only rarely examined the ways in which law and medicine have defined, regulated, and often oppressed sexual minorities. This is an error on the part of bioethics. Medicine and law have served in the past as society's enforcement arm toward sexual minorities, in ways that robbed many people of their dignity. We feel that bioethics has an obligation to discuss that history and to help us as a society take responsibility for it. We can address only a small number of topics in this special issue of the Hastings Center Report, and we selected topics we believe will stimulate discourse. Andrew Solomon offers an elegant overview of the challenges that bioethics faces in articulating a solid basis for LGBT rights. Timothy F. Murphy asks whether bioethics still faces issues related to lesbian, gay, and bisexual people, given the deletion of homosexuality as a disease and the progress toward same-sex marriage. Jamie Lindemann Nelson's essay addresses the search for identity for transgender persons and the role of science in that search. Two articles, those by Brendan S. Abel and by Jack Drescher and Jack Pula, take up the complex issue of medical treatment for children who reject their assigned birth gender. Celia B. Fisher and Brian Mustanski address the special challenges of engaging LGBT youth in research, balancing the need for better information about this vulnerable group against the existing restrictions on research involving children. Tia Powell and Edward Stein consider the merits of legal bans on psychotherapies intended to change sexual orientation, particularly in the light of current research on orientation. Mary Beth Foglia and Karen I. Fredricksen-Goldsen highlight health disparities and resilience among LGBT older adults and then discuss the role of nonconscious bias in perpetuating

  10. Model parameter estimations from residual gravity anomalies due to simple-shaped sources using Differential Evolution Algorithm

    NASA Astrophysics Data System (ADS)

    Ekinci, Yunus Levent; Balkaya, Çağlayan; Göktürkler, Gökhan; Turan, Seçil

    2016-06-01

    An efficient approach to estimate model parameters from residual gravity data based on differential evolution (DE), a stochastic vector-based metaheuristic algorithm, has been presented. We have showed the applicability and effectiveness of this algorithm on both synthetic and field anomalies. According to our knowledge, this is a first attempt of applying DE for the parameter estimations of residual gravity anomalies due to isolated causative sources embedded in the subsurface. The model parameters dealt with here are the amplitude coefficient (A), the depth and exact origin of causative source (zo and xo, respectively) and the shape factors (q and ƞ). The error energy maps generated for some parameter pairs have successfully revealed the nature of the parameter estimation problem under consideration. Noise-free and noisy synthetic single gravity anomalies have been evaluated with success via DE/best/1/bin, which is a widely used strategy in DE. Additionally some complicated gravity anomalies caused by multiple source bodies have been considered, and the results obtained have showed the efficiency of the algorithm. Then using the strategy applied in synthetic examples some field anomalies observed for various mineral explorations such as a chromite deposit (Camaguey district, Cuba), a manganese deposit (Nagpur, India) and a base metal sulphide deposit (Quebec, Canada) have been considered to estimate the model parameters of the ore bodies. Applications have exhibited that the obtained results such as the depths and shapes of the ore bodies are quite consistent with those published in the literature. Uncertainty in the solutions obtained from DE algorithm has been also investigated by Metropolis-Hastings (M-H) sampling algorithm based on simulated annealing without cooling schedule. Based on the resulting histogram reconstructions of both synthetic and field data examples the algorithm has provided reliable parameter estimations being within the sampling limits of

  11. Microbial structures in an Alpine Thermal Spring - Microscopic techniques for the examination of Biofilms in a Subsurface Environment

    NASA Astrophysics Data System (ADS)

    Dornmayr-Pfaffenhuemer, Marion; Pierson, Elisabeth; Janssen, Geert-Jan; Stan-Lotter, Helga

    2010-05-01

    The research into extreme environments hast important implications for biology and other sciences. Many of the organisms found there provide insights into the history of Earth. Life exists in all niches where water is present in liquid form. Isolated environments such as caves and other subsurface locations are of interest for geomicrobiological studies. And because of their "extra-terrestrial" conditions such as darkness and mostly extreme physicochemical state they are also of astrobiological interest. The slightly radioactive thermal spring at Bad Gastein (Austria) was therefore examined for the occurrence of subsurface microbial communities. The surfaces of the submerged rocks in this warm spring were overgrown by microbial mats. Scanning electron microscopy (SEM) performed by the late Dr. Wolfgang Heinen revealed an interesting morphological diversity in biofilms found in this environment (1, 2). Molecular analysis of the community structure of the radioactive subsurface thermal spring was performed by Weidler et al. (3). The growth of these mats was simulated using sterile glass slides which were exposed to the water stream of the spring. Those mats were analysed microscopically. Staining, using fluorescent dyes such as 4',6-Diamidino-2-phenylindol (DAPI), gave an overview of the microbial diversity of these biofilms. Additional SEM samples were prepared using different fixation protocols. Scanning confocal laser microscopy (SCLM) allowed a three dimensional view of the analysed biofilms. This work presents some electron micrographs of Dr. Heinen and additionally new microscopic studies of the biofilms formed on the glass slides. The appearances of the new SEM micrographs were compared to those of Dr. Heinen that were done several years ago. The morphology and small-scale distribution in the microbial mat was analyzed by fluorescence microscopy. The examination of natural biomats and biofilms grown on glass slides using several microscopical techniques

  12. Source rocks, thermal history and oil in the Carson Sink and Buena Vista Valley, west central Nevada

    SciTech Connect

    Barker, C.E.

    1995-06-01

    Rock-Eval, gas chromatography, mass spectrometry, and thermal history reconstruction data from six wells suggest that Tertiary rocks in the Carson Sink and Buena Vista Valley areas are marginally mature to overmature with respect to hydrocarbon generation and have locally expelled oil. The lacustrine Tertiary calcareous mudstones and marls in these wells have a total organic carbon (TOC) range from 0.1 to 3 wt.-%, with modes at about 0.5 to 0.7, 1.5, and 2 to 3 wt-% TOC. However, in the Standard Amoco Carson Sink 1 well, some of these samples have up to 3 wt-% less TOC than reported by Hastings (1979) and these are thought to represent drill cutting samples that have been depleted in more TOC rich rock chips. Even if the TOC data are biased, these TOC-depleted samples are still oil-prone rocks, with hydrogen indices commonly above 400 mg hydrocarbon/g C, and some samples with TOC in the 2-3 wt.-% range. Analysis of an oil show at Kyle Hot Springs in Buena Vista Valley revealed a wax-rich, low sulfur oil probably from a carbonate-rich, hypersaline lacustrine source rock. This oil could be generated from strata similar to those analyzed above. Other Tertiary source rocks in the two valleys consist of lenses of humic coals that appear to be gas prone. Shows of biogenic(?) gas from shallow wells in Tertiary to Holocene lacustrine strata are common in the Carson Sink. Mesozoic rocks locally may have remaining hydrocarbon generation potential in the Stillwater Range which lie along the eastern margin of the Carson Sink. Published conodont alteration index data shows that the Paleozoic rocks are overmature. Reconstructed thermal histories of the Carson Sink and Buena Vista Valley areas, indicate petroleum is presently being generated. Mechanisms for petroleum generation are rapid burial (140 m/m.y.) in a high geothermal gradient (45 to 110{degrees}C/km), and hydrothermal and contact metamorphism.

  13. SU-E-T-58: A Novel Monte Carlo Photon Transport Simulation Scheme and Its Application in Cone Beam CT Projection Simulation

    SciTech Connect

    Xu, Y; Tian, Z; Jiang, S; Jia, X; Zhou, L

    2015-06-15

    Purpose: Monte Carlo (MC) simulation is an important tool to solve radiotherapy and medical imaging problems. Low computational efficiency hinders its wide applications. Conventionally, MC is performed in a particle-by -particle fashion. The lack of control on particle trajectory is a main cause of low efficiency in some applications. Take cone beam CT (CBCT) projection simulation as an example, significant amount of computations were wasted on transporting photons that do not reach the detector. To solve this problem, we propose an innovative MC simulation scheme with a path-by-path sampling method. Methods: Consider a photon path starting at the x-ray source. After going through a set of interactions, it ends at the detector. In the proposed scheme, we sampled an entire photon path each time. Metropolis-Hasting algorithm was employed to accept/reject a sampled path based on a calculated acceptance probability, in order to maintain correct relative probabilities among different paths, which are governed by photon transport physics. We developed a package gMMC on GPU with this new scheme implemented. The performance of gMMC was tested in a sample problem of CBCT projection simulation for a homogeneous object. The results were compared to those obtained using gMCDRR, a GPU-based MC tool with the conventional particle-by-particle simulation scheme. Results: Calculated scattered photon signals in gMMC agreed with those from gMCDRR with a relative difference of 3%. It took 3.1 hr. for gMCDRR to simulate 7.8e11 photons and 246.5 sec for gMMC to simulate 1.4e10 paths. Under this setting, both results attained the same ∼2% statistical uncertainty. Hence, a speed-up factor of ∼45.3 was achieved by this new path-by-path simulation scheme, where all the computations were spent on those photons contributing to the detector signal. Conclusion: We innovatively proposed a novel path-by-path simulation scheme that enabled a significant efficiency enhancement for MC particle

  14. Imaging the concealed section of the Whakatane fault below Whakatane city, New Zealand, with a shear wave land streamer system

    NASA Astrophysics Data System (ADS)

    Polom, Ulrich; Mueller, Christof; Krawczyk, CharLotte M.

    2016-04-01

    The Mw 7.1 Darfield Earthquake in September 2010 ruptured the surface along the Greendale Fault that was not known prior to the earthquake. The subsequent Mw 6.3 Christchurch earthquake in February 2011 demonstrated that concealed active faults have a significant risk potential for urban infrastructure and human life in New Zealand if they are located beneath or close to such areas. Mapping exposures and analysis of active faults incorporated into the National Seismic Hazard Model (NSHM) suggests that several thousands of these active structures are yet to be identified and have the potential to generate moderate to large magnitude earthquakes (i.e. magnitudes >5). Geological mapping suggests that active faults pass beneath, or within many urban areas in New Zealand, including Auckland, Blenheim, Christchurch, Hastings/Napier, Nelson, Rotorua, Taupo, Wellington, and Whakatane. Since no established methodology for routinely locating and assessing the earthquake hazard posed by concealed active faults is available, the principal objective of the presented study was to evaluate the usefulness of high-resolution shear wave seismic reflection profiling using a land streamer to locate buried faults in urban areas of New Zealand. During the survey carried out in the city of Whakatane in February 2015, the method was first tested over a well known surface outcrop of the Edgecumbe Fault 30 km south-west of Whakatane city. This allowed further to investigate the principle shear wave propagation characteristics in the unknown sediments, consisting mainly of effusive rock material of the Taupo volcanic zone mixed with marine transgression units. Subsequently the survey was continued within Whakatane city using night operation time slots to reduce the urban noise. In total, 11 profiles of 5.7 km length in high data quality were acquired, which clearly show concealed rupture structures of obviously different age in the shallow sediments down to 100 m depth. Subject to depth

  15. Making Space Travel to Jupiter Possible

    NASA Technical Reports Server (NTRS)

    Barker, Samuel P.

    2004-01-01

    into the Nb1Zr causing imbrittlement and possibly major failure. I will be testing the effects of Hast-X on Nb1Zr in a high temperature for 10, 50, 100, and 500 hours. After the samples are run through the heat treatment, strength and chemistry will be tested and reported. My appreciation for the research that goes behind every project has and will continue to grow. By digging through old documents written in the 50's and 60's, scouring through forgotten closets, and learning from those with experience in the refractory metals, I am bound to have an incredible learning experience here at NASA.

  16. Chemical composition of Texas surface waters, 1949

    USGS Publications Warehouse

    Irelan, Burdge

    1950-01-01

    This report is the fifth the a series of publications by the Texas Board of Water Engineers giving chemical analyses of the surface waters in the State of Texas. The samples for which data are given were collected between October 1, 1948 and September 30, 1949. During the water year 25 daily sampling stations were maintained by the Geological Survey. Sampled were collected less frequently during the year at many other points. Quality of water records for previous years can be found in the following reports: "Chemical Composition of Texas Surface Waters, 1938-1945," by W. W. Hastings, and J. H. Rowley; "Chemical Composition of Texas Surface Waters, 1946," by W. W. Hastings and B. Irelan; "Chemical Composition of Texas Surface Waters, 1947," by B. Irelan and J. R. Avrett; "Chemical Composition of Texas Surface Waters, 1948," by B. Irelan, D. E. Weaver, and J. R. Avrett. These reports may be obtained from the Texas Board of Water Engineers and Geological Survey at Austin, Texas. Samples for chemical analysis were collected daily at or near points on streams where gaging stations are maintained for measurement of discharge. Most of the analyses were made of 10-day composites of daily samples collected for a year at each sampling point. Three composite samples were usually prepared each month by mixing together equal quantities of daily samples collected for the 1st to the 10th, from the 11th to the 20th, and during the remainder of the month. Monthly composites were made at a few stations where variation in daily conductance was small. For some streams that are subject to sudden large changes in chemical composition, composite samples were made for shorter periods on the basis of the concentration of dissolved solids as indicated by measurement of specific conductance of the daily samples. The mean discharge for the composite period is reported in second-feet. Specific conductance values are expressed as "micromhos, K x 10 at 25° C." Silica, calcium, magnesium, sodium

  17. Can we reliably estimate managed forest carbon dynamics using remotely sensed data?

    NASA Astrophysics Data System (ADS)

    Smallman, Thomas Luke; Exbrayat, Jean-Francois; Bloom, A. Anthony; Williams, Mathew

    2015-04-01

    Forests are an important part of the global carbon cycle, serving as both a large store of carbon and currently as a net sink of CO2. Forest biomass varies significantly in time and space, linked to climate, soils, natural disturbance and human impacts. This variation means that the global distribution of forest biomass and their dynamics are poorly quantified. Terrestrial ecosystem models (TEMs) are rarely evaluated for their predictions of forest carbon stocks and dynamics, due to a lack of knowledge on site specific factors such as disturbance dates and / or managed interventions. In this regard, managed forests present a valuable opportunity for model calibration and improvement. Spatially explicit datasets of planting dates, species and yield classification, in combination with remote sensing data and an appropriate data assimilation (DA) framework can reduce prediction uncertainty and error. We use a Baysian approach to calibrate the data assimilation linked ecosystem carbon (DALEC) model using a Metropolis Hastings-Markov Chain Monte Carlo (MH-MCMC) framework. Forest management information is incorporated into the data assimilation framework as part of ecological and dynamic constraints (EDCs). The key advantage here is that DALEC simulates a full carbon balance, not just the living biomass, and that both parameter and prediction uncertainties are estimated as part of the DA analysis. DALEC has been calibrated at two managed forests, in the USA (Pinus taeda; Duke Forest) and UK (Picea sitchensis; Griffin Forest). At each site DALEC is calibrated twice (exp1 & exp2). Both calibrations (exp1 & exp2) assimilated MODIS LAI and HWSD estimates of soil carbon stored in soil organic matter, in addition to common management information and prior knowledge included in parameter priors and the EDCs. Calibration exp1 also utilises multiple site level estimates of carbon storage in multiple pools. By comparing simulations we determine the impact of site

  18. Asteroid orbital inversion using uniform phase-space sampling

    NASA Astrophysics Data System (ADS)

    Muinonen, K.; Pentikäinen, H.; Granvik, M.; Oszkiewicz, D.; Virtanen, J.

    2014-07-01

    a set of virtual observations; second, corresponding virtual least-squares orbital elements are derived using the Nelder-Mead downhill simplex method; third, repeating the procedure two times allows for a computation of a difference for two sets of virtual orbital elements; and, fourth, this orbital-element difference constitutes a symmetric proposal in a random-walk Metropolis-Hastings algorithm, avoiding the explicit computation of the proposal p.d.f. In a discrete approximation, the allowed proposals coincide with the differences that are based on a large number of pre-computed sets of virtual least-squares orbital elements. The virtual-observation MCMC method is thus based on the characterization of the relevant volume in the orbital-element phase space. Here we utilize MCMC to map the phase-space domain of acceptable solutions. We can make use of the proposal p.d.f.s from the MCMC ranging and virtual-observation methods. The present phase-space mapping produces, upon convergence, a uniform sampling of the solution space within a pre-defined χ^2-value. The weights of the sampled orbital elements are then computed on the basis of the corresponding χ^2-values. The present method resembles the original ranging method. On one hand, MCMC mapping is insensitive to local extrema in the phase space and efficiently maps the solution space. This is somewhat contrary to the MCMC methods described above. On the other hand, MCMC mapping can suffer from producing a small number of sample elements with small χ^2-values, in resemblance to the original ranging method. We apply the methods to example near-Earth, main-belt, and transneptunian objects, and highlight the utilization of the methods in the data processing and analysis pipeline of the ESA Gaia space mission.

  19. Carbon Capture and Sequestration from a Hydrogen Production Facility in an Oil Refinery

    SciTech Connect

    Engels, Cheryl; Williams, Bryan, Valluri, Kiranmal; Watwe, Ramchandra; Kumar, Ravi; Mehlman, Stewart

    2010-06-21

    The project proposed a commercial demonstration of advanced technologies that would capture and sequester CO2 emissions from an existing hydrogen production facility in an oil refinery into underground formations in combination with Enhanced Oil Recovery (EOR). The project is led by Praxair, Inc., with other project participants: BP Products North America Inc., Denbury Onshore, LLC (Denbury), and Gulf Coast Carbon Center (GCCC) at the Bureau of Economic Geology of The University of Texas at Austin. The project is located at the BP Refinery at Texas City, Texas. Praxair owns and operates a large hydrogen production facility within the refinery. As part of the project, Praxair would construct a CO2 capture and compression facility. The project aimed at demonstrating a novel vacuum pressure swing adsorption (VPSA) based technology to remove CO2 from the Steam Methane Reformers (SMR) process gas. The captured CO2 would be purified using refrigerated partial condensation separation (i.e., cold box). Denbury would purchase the CO2 from the project and inject the CO2 as part of its independent commercial EOR projects. The Gulf Coast Carbon Center at the Bureau of Economic Geology, a unit of University of Texas at Austin, would manage the research monitoring, verification and accounting (MVA) project for the sequestered CO2, in conjunction with Denbury. The sequestration and associated MVA activities would be carried out in the Hastings field at Brazoria County, TX. The project would exceed DOE?s target of capturing one million tons of CO2 per year (MTPY) by 2015. Phase 1 of the project (Project Definition) is being completed. The key objective of Phase 1 is to define the project in sufficient detail to enable an economic decision with regard to proceeding with Phase 2. This topical report summarizes the administrative, programmatic and technical accomplishments completed in Phase 1 of the project. It describes the work relative to project technical and design activities

  20. Carbon Capture and Sequestration (via Enhanced Oil Recovery) from a Hydrogen Production Facility in an Oil Refinery

    SciTech Connect

    Stewart Mehlman

    2010-06-16

    The project proposed a commercial demonstration of advanced technologies that would capture and sequester CO2 emissions from an existing hydrogen production facility in an oil refinery into underground formations in combination with Enhanced Oil Recovery (EOR). The project is led by Praxair, Inc., with other project participants: BP Products North America Inc., Denbury Onshore, LLC (Denbury), and Gulf Coast Carbon Center (GCCC) at the Bureau of Economic Geology of The University of Texas at Austin. The project is located at the BP Refinery at Texas City, Texas. Praxair owns and operates a large hydrogen production facility within the refinery. As part of the project, Praxair would construct a CO2 capture and compression facility. The project aimed at demonstrating a novel vacuum pressure swing adsorption (VPSA) based technology to remove CO2 from the Steam Methane Reformers (SMR) process gas. The captured CO2 would be purified using refrigerated partial condensation separation (i.e., cold box). Denbury would purchase the CO2 from the project and inject the CO2 as part of its independent commercial EOR projects. The Gulf Coast Carbon Center at the Bureau of Economic Geology, a unit of University of Texas at Austin, would manage the research monitoring, verification and accounting (MVA) project for the sequestered CO2, in conjunction with Denbury. The sequestration and associated MVA activities would be carried out in the Hastings field at Brazoria County, TX. The project would exceed DOE’s target of capturing one million tons of CO2 per year (MTPY) by 2015. Phase 1 of the project (Project Definition) is being completed. The key objective of Phase 1 is to define the project in sufficient detail to enable an economic decision with regard to proceeding with Phase 2. This topical report summarizes the administrative, programmatic and technical accomplishments completed in Phase 1 of the project. It describes the work relative to project technical and design activities

  1. MAGNOX:BUTEX URANIUM BEARING GLASSES PHYSICAL AND CHEMICAL ANALYSIS DATA PACKAGE

    SciTech Connect

    Peeler, D.; Imrich, K.; Click, D.

    2011-03-08

    Sellafield Ltd (United Kingdom) has requested technical support from the Savannah River National Laboratory (SRNL) to characterize a series of uranium-bearing, mixed alkali borosilicate glasses [WFO (2010)]. The specific glasses to be characterized are based on different blends of Magnox (WRW17 simulant) and Butex (or HASTs 1 and 2) waste types as well as different incorporation rates (or waste loadings) of each blend. Specific Magnox:Butex blend ratios of interest include: 75:25, 60:40, and 50:50. Each of these waste blend ratios will be mixed with a base glass additive composition targeting waste loadings (WLs) of 25, 28, and 32% which will result in nine different glasses. The nine glasses are to be fabricated and physically characterized to provide Sellafield Ltd with the technical data to evaluate the impacts of various Magnox:Butex blend ratios and WLs on key glass properties of interest. It should be noted that the use of 'acceptable' in the Work for Other (WFO) was linked to the results of a durability test (more specifically the Soxhlet leach test). Other processing (e.g., viscosity ({eta}), liquidus temperature (T{sub L})) or product performance (e.g., Product Consistency Test (PCT) results - in addition to the Soxhlet leach test) property constraints were not identified. For example, a critical hold point in the classification of an 'acceptable glass' prior to processing high-level waste (HLW) through the Defense Waste Processing Facility (DWPF) is an evaluation of specific processing and product performance properties against pre-defined constraints. This process is referred to as Slurry Mix Evaporator (SME) acceptability in which predicted glass properties (based on compositional measurements) are compared to predefined constraints to determine whether the glass is acceptable [Brown and Postles (1995)]. As an example, although the nominal melter temperature at DWPF is 1150 C, there is a T{sub L} constraint (without uncertainties applied) of 1050 C. Any

  2. Analysis of the Thermo-Elastic Response of Space Reflectors to Simulated Space Environment

    NASA Astrophysics Data System (ADS)

    Allegri, G.; Ivagnes, M. M.; Marchetti, M.; Poscente, F.

    2002-01-01

    high pressure Xenon lamps to simulate the direct solar irradiation and a cryogenic heat exchanger to reproduce the earth shadowing of sunlight. The temperature of the thermal cycles ranges from -80°C up to 100°C: the thermo-elastic response of the antenna has been surveyed by employing strain gauges place on the structures at several different locations. The structure has been subjected to 100 thermal cycles, each of which lasting two hours: the total duration of the exposition to the vacuum environment has been equal to 300 hours. Finally the antenna has been disassembled and its elements have been examined to evaluate the effects of the simulated exposition on each of them: the total mass loss and the final thermo-mechanical properties of the polymeric based materials which constitute the structural core of the antenna have been surveyed. The experimental results have been compared to numerical simulation performed by the NASTRAN code: the basic FEM model, developed for the unexposed antenna, has been updated to take into account the thermo-mechanical degradation of the structural elements and materials. This has allowed to obtain, by extrapolation, a FEM based prevision of the antenna thermo-elastic response for long-term operative conditions. References. [1] D. Hastings, H. Garret "Spacecraft environment interactions", Cambridge University Press, Atmospheric Series, Cambridge, 1996. [2] IAF-01-I.6.05 "On the Reliability of Honeycomb Core Bonding Joint in Sandwich Composite Materials for Space Applications" G. Allegri, U. Lecci, M. Marchetti, F. Poscente, 52° IAF Congress, 2001. [3] Meguro A. and alii, "Technology status of the 13 m aperture deployment antenna reflectors for Engineering Test Satellite VIII", Acta Astronautica, Volume: 47, Issue: 2-9, July - November, 2000, pp. 147-152. [4] Novikov L. S. "Contemporary state of spacecraft/environment interaction research" Radiation Measurements, Volume: 30, Issue: 5, October, 1999, pp. 661-667. [5] IAF-01-I.1

  3. Estimating national forest carbon stocks and dynamics: combining models and remotely sensed information

    NASA Astrophysics Data System (ADS)

    Smallman, Luke; Williams, Mathew

    2016-04-01

    Forests are a critical component of the global carbon cycle, storing significant amounts of carbon, split between living biomass and dead organic matter. The carbon budget of forests is the most uncertain component of the global carbon cycle - it is currently impossible to quantify accurately the carbon source/sink strength of forest biomes due to their heterogeneity and complex dynamics. It has been a major challenge to generate robust carbon budgets across landscapes due to data scarcity. Models have been used but outputs have lacked an assessment of uncertainty, making a robust assessment of their reliability and accuracy challenging. Here a Metropolis Hastings - Markov Chain Monte Carlo (MH-MCMC) data assimilation framework has been used to combine remotely sensed leaf area index (MODIS), biomass (where available) and deforestation estimates, in addition to forest planting and clear-felling information from the UK's national forest inventory, an estimate of soil carbon from the Harmonized World Database (HWSD) and plant trait information with a process model (DALEC) to produce a constrained analysis with a robust estimate of uncertainty of the UK forestry carbon budget between 2000 and 2010. Our analysis estimates the mean annual UK forest carbon sink at -3.9 MgC ha-1yr-1 with a 95 % confidence interval between -4.0 and -3.1 MgC ha-1 yr-1. The UK national forest inventory (NFI) estimates the mean UK forest carbon sink to be between -1.4 and -5.5 MgC ha-1 yr-1. The analysis estimate for total forest biomass stock in 2010 is estimated at 229 (177/232) TgC, while the NFI an estimated total forest biomass carbon stock of 216 TgC. Leaf carbon area (LCA) is a key plant trait which we are able to estimate using our analysis. Comparison of median estimates for LCA retrieved from the analysis and a UK land cover map show higher and lower values for LCA are estimated areas dominated by needle leaf and broad leaf forests forest respectively, consistent with ecological

  4. Controls on the Nitrogen and Oxygen Isotopic Composition (δ 15N, δ 18O, δ 17O) of Atmospheric Nitrate in Princeton, NJ

    NASA Astrophysics Data System (ADS)

    Hastings, M. G.; Malcolm, E.; Kaiser, J.; Sigman, D. M.

    2004-12-01

    The oxygen isotopic composition of atmospheric nitrate reflects the oxidative mechanisms that convert NOx to HNO3, while the nitrogen isotopic composition of atmospheric nitrate may reflect different NOx source signatures and/or fractionations related to NOx chemistry [Michalski et al., 2003; Hastings et al., 2003; Freyer et al., 1993]. New analysis techniques are capable of determining the 15N/14N, 18O/16O and 17O/16O isotope ratios in samples at the nanomolar level [Sigman et al., 2001; Casciotti et al., 2002; see Kaiser et al., session H38]. This allows for the analysis of short-term variations in the isotopes of HNO3 with the potential to diagnose causal relationships by comparing the isotopic data with other features of atmospheric deposition. The 15N/14N, 18O/16O and 17O/16O of nitrate were analyzed from precipitation samples collected on an event-basis in Princeton, NJ between December 2002 and 2003. The nitrate concentration in Princeton rain ranges from 2.5 to 99.7 μ M (mean=21.1 μ M, n=61), similar to that found in other urban areas of New Jersey by the National Atmospheric Deposition Program. The isotopes of nitrate fall in the wide range reported for various environments with the δ 15N ranging from -4.0 to 9.5‰ (vs. air), and the δ 18O and δ 17O ranging from 57.2 to 90.5‰ and 50.7 to 77.8‰ (vs. VSMOW), respectively. The correlation between nitrate and sulfate concentration (R2=0.66) and the lack of a relationship between these major ions and the isotopes of nitrate supports the conclusion that below cloud scavenging is not the dominant control on the isotopic variations observed. Seasonal variations are observed in both the nitrogen and oxygen isotopes of nitrate. Overall the δ 15N is not correlated with either δ 18O or δ 17O, although both the δ 15N and δ 18O average lowest in the summer and highest in the winter. δ 18O is highly correlated with δ 17O of nitrate with anomalous enrichment in 17O relative to 18O (Δ 17O ranges from 19

  5. Frictional properties of DFDP-1 Alpine Fault rocks under hydrothermal conditions and high shear strain

    NASA Astrophysics Data System (ADS)

    Niemeijer, André R.; Boulton, Carolyn; Toy, Virginia; Townend, John; Sutherland, Rupert

    2015-04-01

    has occurred. Thus, depending on the background (nucleation) strain rate, our data indicate that the Alpine Fault should be able to generate earthquakes at all temperatures above room temperature. However, at the highest temperature investigated (600 oC), the transition to velocity-weakening is postponed to slip rates above 10 mm/s (strain rate ~10-2 s-1). This observation, combined with the absence of strength recovery after long holds, suggests that seismic slip may propagate into regions of the fault unlikely to nucleate earthquakes. We propose that in our porous gouges, thermally activated processes operate simultaneously with granular flow, postponing ductile flow to higher temperatures or lower strain rates. Sutherland, R., V.G. Toy, J. Townend, S.C. Cox, J.D. Eccles, D.R. Faulkner, D.J. Prior, R.J.Norris, E. Mariani, C. Boulton, B.M. Carpenter, C.D. Menzies, T.A. Little, M. Hasting, G.De Pascale, R.M. Langridge, H.R. Scott, Z. Reid-Lindroos, B. Fleming (2012), Drilling reveals fluid control on architecture and rupture of the Alpine Fault, New Zealand, Geology,40, 1143-1146, doi:10.1130/G33614.1. Toy, V.G., Craw, D., Cooper, A.F., and R.J. Norris (2010), Thermal regime in the central Alpine Fault zone, New Zealand: Constraints from microstructures, biotite chemistry and fluid inclusion data, Tectonophysics, doi:10.1016/j.tecto.2009.12.013

  6. Long-term tillage and crop rotation effects on residual nitrate in the crop root zone and nitrate accumulation in the intermediate vadose zone

    USGS Publications Warehouse

    Katupitiya, A.; Eisenhauer, D.E.; Ferguson, R.B.; Spalding, R.F.; Roeth, F.W.; Bobier, M.W.

    1997-01-01

    Tillage influences the physical and biological environment of soil. Rotation of crops with a legume affects the soil N status. A furrow irrigated site was investigated for long-term tillage and crop rotation effects on leaching of nitrate from the root zone and accumulation in the intermediate vadose zone (IVZ). The investigated tillage systems were disk-plant (DP), ridge-till (RT) and slot-plant (SP). These tillage treatments have been maintained on the Hastings silt loam (Udic Argiustoll) and Crete silt loam (Pachic Argiustoll) soils since 1976. Continuous corn (CC) and corn soybean (CS) rotations were the subtreatments. Since 1984, soybeans have been grown in CS plots in even calendar years. All tillage treatments received the same N rate. The N rate varied annually depending on the root zone residual N. Soybeans were not fertilized with N-fertilizer. Samples for residual nitrate in the root zone were taken in 8 of the 15 year study while the IVZ was only sampled at the end of the study. In seven of eight years, root zone residual soil nitrate-N levels were greater with DP than RT and SP. Residual nitrate-N amounts were similar in RT and SP in all years. Despite high residual nitrate-N with DP and the same N application rate, crop yields were higher in RT and SP except when DP had an extremely high root zone nitrate level. By applying the same N rates on all tillage treatments, DP may have been fertilized in excess of crop need. Higher residual nitrate-N in DP was most likely due to a combination of increased mineralization with tillage and lower yield compared to RT and SP. Because of higher nitrate availability with DP, the potential for nitrate leaching from the root zone was greater with DP as compared to the RT and SP tillage systems. Spring residual nitrate-N contents of DP were larger than RT and SP in both crop rotations. Ridge till and SP systems had greater nitrate-N with CS than CC rotations. Nitrate accumulation in IVZ at the upstream end of the

  7. Correlation between the Palaeozoic structures from West Iberian and Grand Banks margins using inversion of magnetic anomalies

    NASA Astrophysics Data System (ADS)

    Silva, Elsa A.; Miranda, J. M.; Luis, J. F.; Galdeano, A.

    2000-05-01

    The Ibero-Armorican Arc (IAA) is a huge geological structure of Pre-Cambrian origin, tightened during hercynian times and deeply affected by the opening of the Atlantic Ocean and the Bay of Biscay. Its remnants now lie in Iberia, north-western France and the Canadian Grand Banks margins. The qualitative correlation between these three blocks has been attempted by several authors (e.g. Lefort, J.P., 1980. Un 'Fit' structural de l'Atlantique Nord: arguments geologiques pour correler les marqueurs geophysiques reconnus sur les deux marges. Mar. Geol. 37, 355-369; Lefort, J.P., 1983. A new geophysical criterion to correlate the Acadian and Hercynian orogenies of Western Europe and Eastern America. Mem. Geol. Soc. Am. 158, 3-18; Galdeano, A., Miranda, J.M., Matte, P., Mouge, P., Rossignol, C., 1990. Aeromagnetic data: A tool for studying the Variscan arc of Western Europe and its correlation with transatlantic structures. Tectonophysics 177, 293-305) using magnetic anomalies, mainly because they seem to preserve the hercynian zonation, in spite of the strong thermal and mechanical processes that took place during rifting and ocean spreading. In this paper, we present a new contribution to the study of the IAA structure based on the processing of a compilation of magnetic data from Iberia and Grand Banks margins. To interpret the magnetic signature, a Fourier-domain-based inversion technique was applied, considering a layer with a constant thickness of 10 km, and taking into account only the induced field. The digital terrain model was derived from ETOPO5 (ETOPO5, 1986. Relief map of the earth's surface. EOS 67, 121) and TerrainBase (TerrainBase, 1995. In: Row III, L.W., Hastings, D.A., Dunbar, P.K. (Eds.), Worldwide Digital Terrain Data, Documentation Manual, CD-ROM Release 1.0. GEODAS-NGDC Key to Geophysical Records. Documentation N. 30, April) databases. The pseudo-susceptibility distribution obtained was repositioned for the 156.5 Ma epoch, using the Srivastava and

  8. Lake Charles CCS Project

    SciTech Connect

    Leib, Thomas; Cole, Dan

    2015-06-30

    , construction labor, engineering, and other costs. The CCS Project Final Technical Report is based on a Front End Engineering and Design (FEED) study prepared by SK E&C, completed in [June] 2014. Subsequently, Fluor Enterprises completed a FEED validation study in mid-September 2014. The design analyses indicated that the FEED package was sufficient and as expected. However, Fluor considered the construction risk based on a stick-build approach to be unacceptable, but construction risk would be substantially mitigated through utilization of modular construction where site labor and schedule uncertainty is minimized. Fluor’s estimate of the overall EPC project cost utilizing the revised construction plan was comparable to SKE&C’s value after reflecting Fluor’s assessment of project scope and risk characteristic. Development was halted upon conclusion of Phase 2A FEED and the project was not constructed.Transport and Sequestration – The overall objective of the pipeline project was to construct a pipeline to transport captured CO2 from the Lake Charles Clean Energy project to the existing Denbury Green Line and then to the Hastings Field in Southeast Texas to demonstrate effective geologic sequestration of captured CO2 through commercial EOR operations. The overall objective of the MVA portion of the project was to demonstrate effective geologic sequestration of captured CO2 through commercial Enhanced Oil Recovery (EOR) operations in order to evaluate costs, operational processes and technical performance. The DOE target for the project was to capture and implement a research MVA program to demonstrate the sequestration through EOR of approximately one million tons of CO2 per year as an integral component of commercial operations.

  9. Stratigraphy and structural development of the southwest Isla Tiburón marine basin: Implications for latest Miocene tectonic opening and flooding of the northern Gulf of California

    USGS Publications Warehouse

    Bennett, Scott E K.; Oskin, Michael; Dorsey, Rebecca; Iriondo, Alexander; Kunk, Michael J.

    2015-01-01

    Accurate information on the timing of earliest marine incursion into the Gulf of California (northwestern México) is critical for paleogeographic models and for understanding the spatial and temporal evolution of strain accommodation across the obliquely divergent Pacific-North America plate boundary. Marine strata exposed on southwest Isla Tiburón (SWIT) have been cited as evidence for a middle Miocene marine incursion into the Gulf of California at least 7 m.y. prior to plate boundary localization ca. 6 Ma. A middle Miocene interpretation for SWIT marine deposits has played a large role in subsequent interpretations of regional tectonics and rift evolution, the ages of marine basins containing similar fossil assemblages along ~1300 km of the plate boundary, and the timing of marine incursion into the Gulf of California. We report new detailed geologic mapping and geochronologic data from the SWIT basin, an elongate sedimentary basin associated with deformation along the dextral-oblique La Cruz fault. We integrate these results with previously published biostratigraphic and geochronologic data to bracket the age of marine deposits in the SWIT basin and show that they have a total maximum thickness of ~300 m. The 6.44 ± 0.05 Ma (Ar/Ar) tuff of Hast Pitzcal is an ash-flow tuff stratigraphically below the oldest marine strata, and the 6.01 ± 0.20 Ma (U/Pb) tuff of Oyster Amphitheater, also an ash-flow tuff, is interbedded with marine conglomerate near the base of the marine section. A dike-fed rhyodacite lava flow that caps all marine strata yields ages of 3.51 ± 0.05 Ma (Ar/Ar) and 4.13 ± 0.09 Ma (U/Pb) from the base of the flow, consistent with previously reported ages of 4.16 ± 1.81 Ma (K-Ar) from the flow top and (K-Ar) 3.7 ± 0.9 Ma from the feeder dike. Our new results confirm a latest Miocene to early Pliocene age for the SWIT marine basin, consistent with previously documented latest Miocene to early Pliocene (ca. 6.2-4.3 Ma) planktonic and benthic

  10. LCLS-II New Instruments Workshops Report

    SciTech Connect

    Baradaran, Samira; Bergmann, Uwe; Durr, Herrmann; Gaffney, Kelley; Goldstein, Julia; Guehr, Markus; Hastings, Jerome; Heimann, Philip; Lee, Richard; Seibert, Marvin; Stohr, Joachim; /SLAC

    2012-08-08

    The LCLS-II New Instruments workshops chaired by Phil Heimann and Jerry Hastings were held on March 19-22, 2012 at the SLAC National Accelerator Laboratory. The goal of the workshops was to identify the most exciting science and corresponding parameters which will help define the LCLS-II instrumentation. This report gives a synopsis of the proposed investigations and an account of the workshop. Scientists from around the world have provided short descriptions of the scientific opportunities they envision at LCLS-II. The workshops focused on four broadly defined science areas: biology, materials sciences, chemistry and atomic, molecular and optical physics (AMO). Below we summarize the identified science opportunities in the four areas. The frontiers of structural biology lie in solving the structures of large macromolecular biological systems. Most large protein assemblies are inherently difficult to crystallize due to their numerous degrees of freedom. Serial femtosecond protein nanocrystallography, using the 'diffraction-before-destruction' approach to outrun radiation damage has been very successfully pioneered at LCLS and diffraction patterns were obtained from some of the smallest protein crystals ever. The combination of femtosecond x-ray pulses of high intensity and nanosized protein crystals avoids the radiation damage encountered by conventional x-ray crystallography with focused beams and opens the door for atomic structure determinations of the previously largely inaccessible class of membrane proteins that are notoriously difficult to crystallize. The obtained structures will allow the identification of key protein functions and help in understanding the origin and control of diseases. Three dimensional coherent x-ray imaging at somewhat lower resolution may be used for larger objects such as viruses. The chemistry research areas of primary focus are the predictive understanding of catalytic mechanisms, with particular emphasis on photo- and

  11. EDITORIAL: Focus on Quantum Information and Many-Body Theory

    NASA Astrophysics Data System (ADS)

    Eisert, Jens; Plenio, Martin B.

    2010-02-01

    and F Verstraete SIMULATION AND DYNAMICS A quantum differentiation of k-SAT instances B Tamir and G Ortiz Classical Ising model test for quantum circuits Joseph Geraci and Daniel A Lidar Exact matrix product solutions in the Heisenberg picture of an open quantum spin chain S R Clark, J Prior, M J Hartmann, D Jaksch and M B Plenio Exact solution of Markovian master equations for quadratic Fermi systems: thermal baths, open XY spin chains and non-equilibrium phase transition Tomaž Prosen and Bojan Žunkovič Quantum kinetic Ising models R Augusiak, F M Cucchietti, F Haake and M Lewenstein ENTANGLEMENT AND SPECTRAL PROPERTIES Ground states of unfrustrated spin Hamiltonians satisfy an area law Niel de Beaudrap, Tobias J Osborne and Jens Eisert Correlation density matrices for one-dimensional quantum chains based on the density matrix renormalization group W Münder, A Weichselbaum, A Holzner, Jan von Delft and C L Henley The invariant-comb approach and its relation to the balancedness of multipartite entangled states Andreas Osterloh and Jens Siewert Entanglement scaling of fractional quantum Hall states through geometric deformations Andreas M Läuchli, Emil J Bergholtz and Masudul Haque Entanglement versus gap for one-dimensional spin systems Daniel Gottesman and M B Hastings Entanglement spectra of critical and near-critical systems in one dimension F Pollmann and J E Moore Macroscopic bound entanglement in thermal graph states D Cavalcanti, L Aolita, A Ferraro, A García-Saez and A Acín Entanglement at the quantum phase transition in a harmonic lattice Elisabeth Rieper, Janet Anders and Vlatko Vedral Multipartite entanglement and frustration P Facchi, G Florio, U Marzolino, G Parisi and S Pascazio Entropic uncertainty relations—a survey Stephanie Wehner and Andreas Winter Entanglement in a spin system with inverse square statistical interaction D Giuliano, A Sindona, G Falcone, F Plastina and L Amico APPLICATIONS Time-dependent currents of one-dimensional bosons

  12. Salt-front movement in the Hudson River estuary, New York—Simulations by one-dimensional flow and solute-transport models

    USGS Publications Warehouse

    de Vries, M. Peter; Weiss, Lawrence A.

    2001-01-01

    The Hudson River is being considered for use as a supplemental source of water supply for New York City during droughts. One proposal entails withdrawal of Hudson River water from locations near Newburgh, Chelsea, or Kingston, but the extent to which this could cause the salt front to advance upstream to points where it could adversely affect community water supplies is unknown. The U.S. Geological Survey (USGS) one-dimensional Branch-Network Dynamic Flow model (BRANCH) was used in conjunction with the USGS one-dimensional Branched Lagrangian Solute-Transport Model (BLTM) to simulate the effect of five water-withdrawal scenarios on the salt-front location.The modeled reach contains 132 miles of the lower Hudson River between the Federal Dam at Troy and Hastings-on-Hudson (near New York City). The BRANCH model was calibrated and verified to 19 tidal-cycle discharge measurements made at 11 locations by conventional and acoustic Doppler current-profiler methods. Maximum measured instantaneous tidal flow ranged from 20,000 ft3/s (cubic feet per second) at Albany to 368,000 ft3/s at Tellers Point; daily-mean flow at Green Island near Troy ranged from 3,030 ft3/s to 45,000 ft3/s during the flow measurements. Successive ebb- and flood-flow volumes were measured and compared with computed volumes; daily-mean bias was -1.6 percent (range from -21.0 to +23.7 percent; 13.5 percent mean absolute error). Daily-mean deviation between simulated and measured stage at eight locations (from Bowline Point to Albany) over the 19 tidal-cycle measurements averaged +0.06 ft (range from -0.31 to +0.40 ft; 0.21 ft root mean square error, RMSE). These results indicate that the model can accurately simulate flow in the Hudson River under a wide range of flow, tide, and meteorological conditions.The BLTM was used to simulate chloride transport in the 61-mi reach from Turkey Point to Bowline Point under two seasonal conditions in 1990.one representing spring conditions of high inflow and low

  13. BOOK REVIEW: Seeking Ultimates. An Intuitive Guide to Physics

    NASA Astrophysics Data System (ADS)

    Brown, Neil

    2000-05-01

    : entropy. It is physicists who can benefit most from discarding mathematics and seeking intuitive understanding. It is often too easy to put the numbers into a formula, with little real comprehension of the underlying physics. For layman or physicist the book is hard work. It is not a volume to be read from cover to cover; each section needs to be considered and digested, with frequent turning backwards (or sometimes forwards) to other pages. Even then the outcome may leave questions that can only be answered by access to an academic library to look up some of the copious references to original papers (which, of course, do not eschew mathematics or make concessions to conceptual difficulties). Unfortunately the book is marred by an impression of haste and lack of care, leading to errors that should not have reached the final print. For example, a graph of increase of population with generation number is shown as and stated to be a straight line. It should be exponential. This sort of thing undermines confidence in the whole text. High temperature superconductivity may have a revolutionary effect on electrical machines in the future, but for the time being magnets for magnetic resonance imaging machines and the like still use the old superconductors. Amusing anecdotes make for interesting reading, but the one about Faraday is garbled: he had nothing to do with frogs' legs (that was Galvani), and the quip about taxing electricity one day, if not apocryphal, was made either to Peel or to Gladstone, not to the King. In at least one case a topic mentioned in the index and glossary does not appear on the stated page in the text, apparently having been cut out at a late stage. Personally I did not find the book satisfying, but others will differ. Especially when dealing with intuitive appreciation, what is straightforward to one person may be utterly opaque to another. Making physics comprehensible and conveying its fascination is a daunting and often thankless task, but a very

  14. Oroclines in the Tasmanides

    NASA Astrophysics Data System (ADS)

    Musgrave, Robert J.

    2015-11-01

    secondary. In contrast to the other orogens, consensus that at least part of the curvature in the Palaeozoic to Triassic New England Orogen is oroclinal has been broad, although not universal. There remains substantial debate over the number of hinges (from two to four) and mechanism. Palaeomagnetic poles have previously been cited as evidence of rotation of blocks within the orocline, but this paper presents the first formal palaeomagnetic orocline test, which is positive for the Manning and Texas hinges. A palaeocurrent orocline test of the Manning hinge, in younger rocks than the palaeomagnetic sample, is negative, constraining rotation in the southern, Manning hinge to the Carboniferous before 322 Ma, while rotation in the northern, Texas hinge appears to be latest Carboniferous or Permian. The existence of a Hastings hinge is questionable, but if real, its rotation also appears to be younger than that of the Manning hinge. Thick-skinned, secondary rotation of the hinges of the New England orocline appears to have been diachronous.

  15. Seismic imaging of major tectonic features in the crust of Phanerozoic eastern Australia

    NASA Astrophysics Data System (ADS)

    Finlayson, D. M.; Wake-Dyster, K. D.; Leven, J. H.; Johnstone, D. W.; Murray, C. G.; Harrington, H. J.; Korsch, R. J.; Wellman, P.

    1990-02-01

    England Fold Belt we interpret a high-angle geosuture extending through the crust (the Burunga-Mooki geosuture). Reactivation during late Palaeozoic-early Mesozoic times produced a series of reverse faults along the uplifted eastern margin of the trough. Some of these structures are tentatively considered to be positive flower structures above deeper faults with strike-slip movement. The geosuture separates regions with distinctly different Seismic fabrics and played an important role in the formation of the Bowen-Gunne-dah-Sydney Basin system. (5)Within the New England Fold Belt, crustal domains can be recognized associated with late Palaeozoic oroclinal bending and early Mesozoic trans-tensional basins. Major oroclinal bending of the upper crust in the west of the fold belt is interpreted above a mid-crustal detachment (the Texas detachment). In the central part of the fold belt, the Seismic data support a trans-tensional mechanism for the formation of Triassic basins with steeply dipping bounding faults. Under the east of the fold belt, an imbricate thrust stack/accretionary wedge is clearly imaged above a mid-crustal horizon (the Brisbane mid-crustal detachment). Upper crustal deformation appears to have occurred above this detachment. (6)From the Nebine Ridge to the coast, the Moho is clearly defined below a 3-km thick Moho transition zone. Hast of the Thomson Fold Belt, the Moho level is identified as a gently undulating feature at 36-38 km depth and probably re-established after the major late Palaeozoic tectonic events which formed the crust under the Taroom Trough and New England Fold Belt. This contrasts with the middle Palaeozoic lower crustal/Moho features which appear to be preserved under the Thomson Fold Belt. (7)The thickest crust under the Nebine Ridge (about 44 km) appears to be associated with lower crustal wedging from the east. There is an apparent thinning of the non-sedimentary crust under the deepest basin (Taroom Trough) of about 30% compared with

  16. SPIG From Beginning To Today

    NASA Astrophysics Data System (ADS)

    Labat, J.

    2010-07-01

    physics of ionized gases should be done in a more organized manner. Already in the summer of 1964 the "Summer School on the Physics of Ionized Gases" has been held in Herceg Novi, small town on the Adriatic coast. Six internationally recognized lecturers were invited to give a series of lectures in various fields. These were: prof. J. D. Craggs (Univ. of Liverpool, UK, 3 lectures) prof. A. L. Cullen (Univ. of Sheffield, UK, 3 lectures), prof. Yu. H. Demkov (Univ. of Leningrad, 3 lectures), prof. A. von Engel (Univ. of Oxford, UK, 8 lectures), dr. R. Herman (Obs. de Paris, France, 2 lectures), prof. J. B. Hasted (Univ. College, London, UK, 6 lectures). They were actually the first real teachers for the young and growing generation of Yugoslav scientists working in the field of ionized gases, and their names should be praised with dignity and gratitude. Good results of this summer school suggested that the school of this type should be organized on a regular basis and possibly combined with the symposium. This idea has been accepted by all the participants and as a result of this idea in 1968 the first meeting in a long lasting series was held under the full name: "Yugoslav Symposium and International Summer School on the Physics of Ionized Gases", now known world wide as SPIG. Mainly foreign participants insisted that it should be held somewhere on the Adriatic coast. Until 1990, with the exception of XIV SPIG (held in Sarajevo) all were organized in an attractive summer resorts along Adriatic coast, on a regular, two year basis. Yugoslavia fell apart in 1991, and the regular 1992 term has been omitted. The renowned XVI SPIG meting has been held in Belgrade in spite of general crisis and isolation of newly formed Federal Republic of Yugoslavia. The next one, for the same reason, was also organized in Belgrade. The number of foreign participants dropped down sharply due to war surrounding and largely unsettled situation. However, the general situation in the country

  17. Salt-front movement in the Hudson River estuary, New York : simulations by one-dimensional flow and solute-transport models

    USGS Publications Warehouse

    de Vries, M. Peter; Weiss, L.A.

    2001-01-01

    The Hudson River is being considered for use as a supplemental source of water supply for New York City during droughts. One proposal entails withdrawal of Hudson River water from locations near Newburgh, Chelsea, or Kingston, but the extent to which this could cause the salt front to advance upstream to points where it could adversely affect community water supplies is unknown. The U.S. Geological Survey (USGS) one-dimensional Branch-Network Dynamic Flow model (BRANCH) was used in conjunction with the USGS one-dimensional Branched Lagrangian Solute-Transport Model (BLTM) to simulate the effect of five water-withdrawal scenarios on the salt-front location. The modeled reach contains 132 miles of the lower Hudson River between the Federal Dam at Troy and Hastings-on-Hudson (near New York City). The BRANCH model was calibrated and verified to 19 tidal-cycle discharge measurements made at 11 locations by conventional and acoustic Doppler current-profiler methods. Maximum measured instantaneous tidal flow ranged from 20,000 ft3/s (cubic feet per second) at Albany to 368,000 ft3/s at Tellers Point; daily-mean flow at Green Island near Troy ranged from 3,030 ft3/s to 45,000 ft3/s during the flow measurements. Successive ebb- and flood-flow volumes were measured and compared with computed volumes; daily-mean bias was -1.6 percent (range from -21.0 to +23.7 percent; 13.5 percent mean absolute error). Daily-mean deviation between simulated and measured stage at eight locations (from Bowline Point to Albany) over the 19 tidal-cycle measurements averaged +0.06 ft (range from -0.31 to +0.40 ft; 0.21 ft root mean square error, RMSE). These results indicate that the model can accurately simulate flow in the Hudson River under a wide range of flow, tide, and meteorological conditions. The BLTM was used to simulate chloride transport in the 61-mi reach from Turkey Point to Bowline Point under two seasonal conditions in 1990.one representing spring conditions of high inflow and low

  18. The importance of being informed

    NASA Astrophysics Data System (ADS)

    Draganova, Tamara

    2013-04-01

    other schools in the region and the country. Campaigns were reflected in regional and national media. However, the capital invested in the young people is our responsibility - students, teachers and research workers, parents and citizens should be informed. And this is the power of us all today in order to face the future calmly and confidently, with the knowledge, attitudes and respect for our planet Earth. And we all, teachers are obliged and responsible to be conductors of Geosciences in the classroom today, for the future of our children... "If thou hast Knowledge, let others light their candle at thine..." Thomas Fuller

  19. Software Uncertainty in Integrated Environmental Modelling: the role of Semantics and Open Science

    NASA Astrophysics Data System (ADS)

    de Rigo, Daniele

    2013-04-01

    . Semantic Array Programming for Environmental Modelling: Application of the Mastrave library. In: Seppelt, R., Voinov, A. A., Lange, S., Bankamp, D. (Eds.), International Environmental Modelling and Software Society (iEMSs) 2012 International Congress on Environmental Modelling and Software. Managing Resources of a Limited Planet: Pathways and Visions under Uncertainty, Sixth Biennial Meeting. pp. 1167-1176. http://www.iemss.org/iemss2012/proceedings/D3_1_0715_deRigo.pdf de Rigo, D., 2012. Semantic Array Programming with Mastrave - Introduction to Semantic Computational Modelling. http://mastrave.org/doc/MTV-1.012-1 Free Software Foundation, 2012. What is free software? http://www.gnu.org/philosophy/free-sw.html (revision 1.118 archived at http://www.webcitation.org/6DXqCFAN3 ) Stallman, R. M., 2009. Viewpoint: Why "open source" misses the point of free software. Communications of the ACM 52 (6), 31-33. http://dx.doi.org/10.1145/1516046.1516058 (free access version: http://www.gnu.org/philosophy/open-source-misses-the-point.html ) Lempert, R., Schlesinger, M. E., Jul. 2001. Climate-change strategy needs to be robust. Nature 412 (6845), 375. http://dx.doi.org/10.1038/35086617 Shell, K. M., Nov. 2012. Constraining cloud feedbacks. Science 338 (6108), 755-756. http://dx.doi.org/10.1126/science.1231083 van der Sluijs, J. P., 2012. Uncertainty and dissent in climate risk assessment: A Post-Normal perspective. Nature and Culture 7 (2), 174-195. http://dx.doi.org/10.3167/nc.2012.070204 Lenton, T. M., Held, H., Kriegler, E., Hall, J. W., Lucht, W., Rahmstorf, S., Schellnhuber, H. J., Feb. 2008. Tipping elements in the earth's climate system. Proceedings of the National Academy of Sciences 105 (6), 1786-1793. http://dx.doi.org/10.1073/pnas.0705414105 Hastings, A., Wysham, D. B., Apr. 2010. Regime shifts in ecological systems can occur with no warning. Ecology Letters 13 (4), 464-472. http://dx.doi.org/10.1111/j.1461-0248.2010.01439.x Barnosky, A. D., Hadly, E. A., Bascompte, J

  20. Once a myth, now an object of study - How the perception of comets has changed over the centuries

    NASA Astrophysics Data System (ADS)

    2004-02-01

    symbol of the prophet’s empowerment. Or again Luke 21:11: “And great earthquakes shall be in divers places, and famines, and pestilences; and fearful sights and great signs shall there be from heaven.” In 1066, Halley’s Comet appeared to many as a harbinger of the Norman conquest of Britain, so vividly portrayed in the Bayeux tapestry, with its scenes from the Battle of Hastings. The decisive step towards overturning the view that comets are atmospheric phenomena was taken in 1577 by Danish astronomer, Tycho Brahe. For two and a half months he observed from his observatory in Uranienburg the progress of a comet across the heavens. Relying on the phenomenon of the daily parallax - an apparent “shuddering” motion of heavenly bodies in fact attributable to the observer’s position on the revolving Earth - he was able to establish that the comet had to be located beyond the lunar orbit. Halley discovers an elliptical orbit The scientific description of comets took another major step forward in 1705 thanks to the work of the British astronomer and physicist, Edmond Halley, a friend and patron of Isaac Newton. Investigating recorded comet measurements, he observed that the orbits of a number of bright comets were very similar: his own calculation of the orbit of a comet observed in 1682 coincided with the data recorded by Johannes Kepler in 1607 and by Apianus in 1531. He concluded that various comet observations were attributable to one and the same comet. Halley was proved right when in December 1758, the comet whose return he had predicted, thenceforth named after him, did indeed make a repeat appearance. This confirmed his theory that apparently parabolic comet orbits were in fact “simply” sections of one enormous elliptical orbit. Since then observations recorded in China in 240 BC have been identified as relating to a sighting of Halley’s comet, the oldest known document dealing with this phenomenon. What was described in the Bible as a sign from God

  1. Farmyard Manure and Fertilizer Effects on Seed Potato (Solanum tuberosum L.) Yield in Green House Production

    NASA Astrophysics Data System (ADS)

    László, M.

    2009-04-01

    %. Entre as misturas 1 e 2, foi melhor a 2. (80% latossolo vermelho novo, 10% palha de arroz queimado, 10% esterco de curral). Examinando-se 15 fatores, entre 11 casos afirmou-se a mistura como para melhor que a mistura 1. (70% latossolo vermelho novo, 20% palha de arroz queimado, 10% esterco de curral). Em caso de número de tuberculos 0-20 mm com a mistura 2. foi possivel aumentar geralmente os números de tuberculos em 77% que a mistura padrão. Efeitos de adubação 1. Área da folhas por planta entre manejo foi melhor de modo significativo a doságem de 3.6 grama vaso-1 adubo complexo (3103 cm2 plantas-1). 2. Peso fresco da folhas e de hastes por plantas as tendencias foram parecidos com o da área de folhas. 3. Peso fresco de raizis por planta até 7.2 grama vaso-1 diminuiu depois aumentou. 4. Peso fresco total de tuberculos por planta as crescentes doságens de um modo forte diminuiram a produção de tuberculos de 0 e 18.0 grama vaso-1 em 160% em os dois caso da mistura. 5. Peso de fitomassa fresco por planta foi melhor a 3.6 g vaso-1 (239 grama planta-1 em médio da dois mistura), depois os dados diminuirám. 6. Produção de biomassa fresco por planta a maxima produção (188 grama planta-1) foi obtida com 3.6 grama vaso-1. Deste ponto de modo forte caiu a produção. 7. Peso da matéria seca de folhas, hastes e raizis por planta somente em caso de mistura padrão o resultado foi significativo em relação aos outros tratamentos. 8. Péso da matéria seca de tuberculos total por planta modo significativo diminuiu a produção (0 e 18.0 grama vaso-1 = 360%) em médio da duas misturas. 9. Biomassa produção de materia seca por planta modo significativo diminuiu para efeito de alta dosagens de adubo complexo (0 e 18.0 grama vaso-1 = 158%) em médio da duas misturas. 10. Peso fresco de tuberculos com 0-20 mm as crescentes dosagens de 0 e 18.0 grama vaso-1 diminuiram a produção em 213% em médio da duas misturas. 11. Peso fresco de tuberculos com 20 mm-1 as