WorldWideScience

Sample records for intertropical convergence zone

  1. An overview of intertropical convergence and intertropical discontinuity

    International Nuclear Information System (INIS)

    Adibe, E.C.

    1992-09-01

    In its simplest form, the general circulation of the atmosphere may be regarded as two meridional circulation in opposite directions and separated by what is sometimes known as the 'meteorological equator'. The meteorological equator, as a planetary entity, divides the troposphere into two meteorological hemispheres, ensuring energy equilibrium in them, and corresponding to what are known as intertropical convergence zone, intertropical discontinuity, intertropical front, monsoon front etc. The meteorological equator moves from the south towards the north and then from the north towards the south in harmony with the apparent movement of the Sun. 11 refs, 14 figs, 1 tab

  2. The Intertropical Convergence Zone over the Middle East and North Africa: Detection and Trends

    KAUST Repository

    Scott, Anna A.

    2013-01-01

    This thesis provides an overview of identifying the Intertropical Convergence Zone (ITCZ) in the Middle East and North Africa (MENA) region. The ITCZ is a zone of wind convergence around the equator that coincides with an area of intense precipitation that is commonly termed a tropical rainbelt. In Africa, these two concepts are frequently confounded. This work studies the correlation between precipitation and commonly used ITCZ indicators. A further attempt is made to detect movement in the African ITCZ, based on earlier paleontological studies showing historical changes in precipitation. Zonally averaged wind convergence is found to be the most reliable indicator of the African ITCZ, one having a low correlation with zonally averaged precipitation. Precipitation is found only to be a reliable indicator for the African ITCZ in zones near the wind convergence, which reaches as far north as 20_N in the summer. No secular change in location of the African ITCZ is found for the time of available data. Finally, historical data shows that any increase in precipitation in the Sahel, a region where precipitation is driven by the ITCZ, is mildly negatively correlated with precipitation in the rainbelt area, suggesting that shifts in the ITCZ result in a widening of the precipitation profile as well as a shift of the entire zone.

  3. The Intertropical Convergence Zone over the Middle East and North Africa: Detection and Trends

    KAUST Repository

    Scott, Anna A.

    2013-05-01

    This thesis provides an overview of identifying the Intertropical Convergence Zone (ITCZ) in the Middle East and North Africa (MENA) region. The ITCZ is a zone of wind convergence around the equator that coincides with an area of intense precipitation that is commonly termed a tropical rainbelt. In Africa, these two concepts are frequently confounded. This work studies the correlation between precipitation and commonly used ITCZ indicators. A further attempt is made to detect movement in the African ITCZ, based on earlier paleontological studies showing historical changes in precipitation. Zonally averaged wind convergence is found to be the most reliable indicator of the African ITCZ, one having a low correlation with zonally averaged precipitation. Precipitation is found only to be a reliable indicator for the African ITCZ in zones near the wind convergence, which reaches as far north as 20_N in the summer. No secular change in location of the African ITCZ is found for the time of available data. Finally, historical data shows that any increase in precipitation in the Sahel, a region where precipitation is driven by the ITCZ, is mildly negatively correlated with precipitation in the rainbelt area, suggesting that shifts in the ITCZ result in a widening of the precipitation profile as well as a shift of the entire zone.

  4. The intertropical convergence zone modulates intense hurricane strikes on the western North Atlantic margin.

    Science.gov (United States)

    van Hengstum, Peter J; Donnelly, Jeffrey P; Fall, Patricia L; Toomey, Michael R; Albury, Nancy A; Kakuk, Brian

    2016-02-24

    Most Atlantic hurricanes form in the Main Development Region between 9°N to 20°N along the northern edge of the Intertropical Convergence Zone (ITCZ). Previous research has suggested that meridional shifts in the ITCZ position on geologic timescales can modulate hurricane activity, but continuous and long-term storm records are needed from multiple sites to assess this hypothesis. Here we present a 3000 year record of intense hurricane strikes in the northern Bahamas (Abaco Island) based on overwash deposits in a coastal sinkhole, which indicates that the ITCZ has likely helped modulate intense hurricane strikes on the western North Atlantic margin on millennial to centennial-scales. The new reconstruction closely matches a previous reconstruction from Puerto Rico, and documents a period of elevated intense hurricane activity on the western North Atlantic margin from 2500 to 1000 years ago when paleo precipitation proxies suggest that the ITCZ occupied a more northern position. Considering that anthropogenic warming is predicted to be focused in the northern hemisphere in the coming century, these results provide a prehistoric analog that an attendant northern ITCZ shift in the future may again return the western North Atlantic margin to an active hurricane interval.

  5. Glacial-Interglacial Changes in the Position of the Intertropical Convergence Zone

    Science.gov (United States)

    Reimi Sipala, M. A.; Marcantonio, F.

    2016-12-01

    The Intertropical Convergence Zone (ITCZ) is a key component of tropical hydroclimate. It is associated with a zonally heterogeneous tropical precipitation maximum which affects the lives of billions. The Central Equatorial Pacific, near the Line Islands, is an ideal location to study ITCZ migration in response to global temperature fluctuations. Our study uses dust records recovered from five locations in the CEP. We address changes in dust provenance, and the response of the paleo-ITCZ to glacial-interglacial transitions around the penultimate termination (150 to 110 ka). Pb and Nd isotope ratios can be used as dust provenance tools, and lead to accurate reconstructions of paleo-ITCZ position, which are decoupled from rainfall intensity and dust flux. Five cores, along a meridional transect at approximately 160° W, give us access to unprecedented high spatial resolution records with core samples at: 0.48° N (ML1208-17PC), 1.27° N (ML1208-20BB), 2.97° N (ML1208-28BB), 4.68° N (ML1208-31BB), and 7.04° N (ML1208-31BB). Our preliminary data suggests that at the location of the equatorial core (17PC) dust is predominantly sourced from South America (average ɛNd = -4.4), but during Heinrich Stadial 11 ( 136-129 ka) there is a rapid isotopic excursion (-3 ɛNd units). This suggests an abrupt change in dust provenance to the CEP potentially associated with an increased influence of northern hemisphere dust. We will present Pb isotope data to further constrain this finding, and discuss the implications of the results for models of abrupt climate change.

  6. Inter-Tropical Convergence Zone Shifts During the Last Glacial Cycle Near the Line Islands Ridge.

    Science.gov (United States)

    Reimi Sipala, M. A.; Marcantonio, F.

    2015-12-01

    This research focuses on the shift in the inter-tropical convergence zone (ITCZ) during the last glacial cycle. Deep sea sediments from the Central Equatorial Pacific (CEP) are used to quantify and isolate the sources and sinks of atmospheric dust. Dust records and influences climate affecting a wide range of process from Earth's Albedo to carbon export. Our aim is to determine the provenance of windblown dust deposited in the CEP near the Line Islands Ridge using radiogenic Nd and Pb isotopes, and to infer the location of the ITCZ and the changes of atmospheric transport through ice-age climate transitions. We focus on three cores from the CEP, along a meridional transect at approximately 160° W --- 0° 28' N (ML1208-17PC), 4° 41' N (ML1208-31BB), and 7 ° 2'N (ML1208-31BB). Radiogenic isotopes (Sr, Nd, Pb) have been successfully used to distinguish between different potential dust sources in the aluminosilicates fractions of Pacific Sediments. Our preliminary data suggest that the equatorial core (17PC) predominantly receives its dust from South America and South American volcanics South America (206Pb/204Pb = 18.62, 207Pb/204Pb = 15.63, 208Pb/204Pb = 38.62; ; ɛNd = ~ -5). The middle core, which more closely reflects the modern position of the ITCZ, has varied dust provenance through time, at times consistent with Asian Loess (average ratios are 206Pb/204Pb = 18.88, 207Pb/204Pb = 15.69, 208Pb/204Pb = 39.06; ɛNd = ~ -7) and Asian Volcanics (ɛNd = ~-1) suggesting a shift in the ITCZ south of 4N before the LGM. Our results for the most northern core are forthcoming. Prior to Holocene time, the changes in Pb isotope ratios in both cores appear to be in anti-phase; the northern core becomes less radiogenic up to the LGM, while the southern core becomes more radiogenic. This is potentially due to a weakening of the ITCZ during glacial times. A secondary aim of this work is to determine if the ITCZ migrated further south than core 17PC during Heinrich stage II.

  7. Balloon-borne ozonesonde and rocket temperature and wind data gathered during the July 1977 intertropical convergence zone experiment

    Science.gov (United States)

    Schmidlin, F. J.; Kloos, G.

    1979-01-01

    In middle latitudes, it is possible for large concentrations of stratospheric air to be brought down to the tropopause through folds or breaks in the tropopause. The exchange of air from the tropopause into higher altitudes is not well understood. Thus, the ITCZ (Intertropical Convergence Zone) experiment, conducted from July 16 through July 31, 1977, included a series of balloon-borne ozone soundings. The results of these soundings are presented and explain in the vertical exchange of air and provide information on the short vertical scales-of-motion. Rocketsonde data was also gathered in the ITCZ experiment in support of a stratospheric scales-of-motion study. The investigation was to determine whether rocketsonde and satellite information currently used yield information on the stratospheric horizontal wave spectrum and its importance with respect to tropospheric and mesospheric interaction and transport.

  8. The Asian Monsoon Links to Solar Changes and the Intertropical Convergence Zone and 1300 Years of Chinese Human Susceptibility

    Science.gov (United States)

    Yu, E.; Hsu, Y.; Lee, T.

    2011-12-01

    Here we present a new paleoclimatic record from a sediment core recovered in Lake Liyutan in central Taiwan over the last 1300 years. The age model is based on 2 AMS 14C dates. Adjustments of age were using the well-dated records from a near by lake sediment core. The Lake Liyutan sediments record the strength of the summer monsoon in two independent ways: (1) the magnetic parameters (ARM/χ, ARM, anhysteresis remenent magnetization; χ, Volume susceptibility) and magnetic susceptibility, and (2) total organic carbon content, organic C/N elemental ratio and δ13Corg of the sediments as a result of changes in different organic matter origins and terrigenous detritus dilution due to precipitation. All the proxy records are 10 to 30- year-resolution. Weaker summer monsoon phases reconstructed from the Lake Liyutan correlate with higher δ18O at Dongge and Hulu caves, which indicates lower summer precipitation rates. Moreover, it is interesting to find that the strong winter monsoon from the Lake Huguang Maar records show a synchronous relationship with weaker summer monsoon from the caves and the Lake Liyutan. From the coincidence in timing, these records were explained by migrations in the intertropical convergence zone. In addition, the weak Asian summer monsoon in the Lake Liyutan corresponds with lowering Northern Hemisphere summer insolation recorded at Dongge cave. Climate variations influenced the agricultural productivity, health risk, and conflict level of preindustrial societies. We note that, on the basis of our new lake record, major changes in Chinese dynasties occurred when the summer monsoon strength was weaker and rainfall was reduced. The Tang dynasty began to ebb in the eighth century, and it fully collapsed in AD907, then the dynastic transitions to the Five Dynasties and Ten Kingdoms period. The weak summer monsoon and reduced rainfall was indicated in the coincidence in timing of the sediment core LYT-3A from Lake Liyutan during 1100 - 1000BP. In

  9. Variabilidade da precipitação em tempo e espaço associada à Zona de Convergência Intertropical Variability of rainfall in time and space associated with Intertropical Convergence Zone

    Directory of Open Access Journals (Sweden)

    Maurício do Nascimento Moura

    2012-12-01

    Full Text Available Este estudo visa apresentar uma análise atmosférica da variabilidade espacial e temporal da Zona de Convergência Intertropical (ZCIT nas cidades de Belém, Jakarta e Nairóbi, que estão localizadas sobre os continentes da América do Sul, Ásia e África, respectivamente. Para isso, foram utilizados dados diários de precipitação observada e radiação de onda longa para o período de 1999 a 2008, e aplicadas as técnicas matemáticas e estatísticas, como a média aritmética e a transformada em ondeletas Morlet. Em geral, os resultados indicam que do ponto de vista espacial, a precipitação mensal varia consideravelmente, pois as três cidades estudadas localizam-se em diferentes continentes da faixa tropical. Isto ocorre principalmente, durante os meses de Janeiro a Maio, período de maior atuação da ZCIT no hemisfério sul. As variações atmosféricas observadas, a partir dos escalogramas de fase, - de ondeleta indicam que as escalas interdecadal, anual, interanual e intrassazonal são moduladoras da precipitação. Tais escalas podem ser representadas pelos mecanismos oceano-atmosfera dos fenômenos El Niño Oscilação Sul e da oscilação intrassazonal de Madden e Julian. A contribuição destes fenômenos na distribuição da chuva nessas regiões é evidente durante o período estudado, sendo que Nairóbi, apesar de estar localizada em latitude semelhante à de Belém, apresenta pouca evidência do ciclo anual e forte na escala interdecadal. No caso de Belém e de Jakarta as oscilações de múltiescala de precipitação concentram-se nas escalas dos mecanismos moduladores da chuva associados com o ciclo anual e intrassazonal, durante todo o período.This study aims to present an atmospheric analysis of spatial and temporal variability of the Intertropical Convergence Zone (ITCZ in Belem, Jakarta and Nairobi, which are located on the continents of South America, Asia and Africa, respectively. For this, daily precipitation and

  10. Solar oven for intertropical zones: Optogeometrical design

    Energy Technology Data Exchange (ETDEWEB)

    Jaramillo, O.A.; Huelsz, G.; Hernandez-Luna, G.; del Rio, J.A. [Centro de Investigacion en Energia. Universidad Nacional Autonoma de Mexico. Priv. Xochicalco S/N. Col. Centro. Temixco, Morelos 62580 (Mexico); Acosta, R. [Universidad de Quintana Roo, Boulevard Bahia s/n Esq. I. Comonfort, Chetumal Quintana Roo 77019 (Mexico); Arriaga, L.G. [Instituto de Investigaciones Electricas, Av. Reforma 113, Col. Palmira, Cuernavaca, Morelos 62490 (Mexico)

    2007-10-15

    In this paper, a novel design of a solar oven for the intertropical zones is presented. The oven box has seven faces instead of the six faces of most common designs reported in the literature, two of them are alternatively used as bases. This oven has four fixed mirrors to concentrate solar energy.The main advantage of this novel design is that the oven needs only four simple movements in order to obtain an adequate solar concentration throughout the year. This feature has been possible due to the optogeometrical design that is presented. A simple theoretical model of the oven concentration is developed. According to the model, the concentration achieved by the oven at noon is greater than 1.95 for all days of the year. In order to analyze the optical performance of the solar cooker, an experimental evaluation was conducted by using a scale model of the solar cooker and a heliodon. (author)

  11. Solar oven for intertropical zones: Optogeometrical design

    International Nuclear Information System (INIS)

    Jaramillo, O.A.; Huelsz, G.; Hernandez-Luna, G.; Rio, J.A. del; Acosta, R.; Arriaga, L.G.

    2007-01-01

    In this paper, a novel design of a solar oven for the intertropical zones is presented. The oven box has seven faces instead of the six faces of most common designs reported in the literature, two of them are alternatively used as bases. This oven has four fixed mirrors to concentrate solar energy.The main advantage of this novel design is that the oven needs only four simple movements in order to obtain an adequate solar concentration throughout the year. This feature has been possible due to the optogeometrical design that is presented. A simple theoretical model of the oven concentration is developed. According to the model, the concentration achieved by the oven at noon is greater than 1.95 for all days of the year. In order to analyze the optical performance of the solar cooker, an experimental evaluation was conducted by using a scale model of the solar cooker and a heliodon

  12. Reconstruction of precipitation variability in the Strait of Yucatan associated with latitudinal shifts in the position of the Intertropical Convergence Zone since the Last Glacial Maximum

    Science.gov (United States)

    Staines-Urías, Francisca; Seidenkrantz, Marit-Solveig; Fischel, Andrea; Kuijpers, Antoon

    2017-04-01

    The elemental composition of sediments from gravity core HOLOVAR11-03 provides a ca. 40 ka record of past climate variability in the Strait of Yucatan, between the Caribbean Sea and the Gulf of Mexico, a region where precipitation variability is determined by the seasonal position of the Intertropical Convergence Zone (ITCZ). Within this region, sea level pressure decreases and rainfall increases as the ITCZ moves north of the equator in response to increased solar insolation in the Northern Hemisphere during boreal summer. In contrast, as the ITCZ retracts southward towards the equator during boreal winter, rainfall diminishes and the regional sea level pressure gradient strengthens. On interannual, multidecadal and millennial timescales, fluctuations in the average latitudinal position of the ITCZ in response to insolation forcing modulate the intensity and duration of the seasonal regimens, determining average regional precipitation and, ultimately, the elemental composition of the marine sedimentary record. Regionally, higher titanium and iron content in marine sediments reflect greater terrigenous input from inland runoff, indicating greater precipitation, hence a more northerly position of the ITCZ. Correspondingly, Ti and Fe concentration data were used to reconstruct regional rainfall variability since the Last Glacial Maxima (LGM ˜24 cal ka BP). HOLOVAR11-03 age model (based on 4 AMS 14C dates obtained from multi-specific samples of planktic foraminifera) shows stable sedimentation rates in the area throughout the cored period. Nonetheless, higher terrestrial mineral input is observed since the LGM and all through the last glacial termination (24 to 12 cal ka BP), indicating a period of increased precipitation. In contrast, lower Ti and Fe values are typical for the period between 12 and 8 cal ka BP, indicating reduced precipitation. A positive trend characterizes the following interval, showing a return to wetter conditions lasting until 5 cal ka BP

  13. Paleoclimate of Quaternary Costa Rica: Analysis of Sediment from ODP Site 1242 in the Eastern Tropical Pacific to Explore the Behavior of the Intertropical Convergence Zone (ITCZ) and Oceanic Circulation

    Science.gov (United States)

    Buczek, C. R.; Joseph, L. H.

    2017-12-01

    Studies of grain size, magnetic fabric, and terrigenous mass accumulation rates (MAR) on oceanic sediment can provide insights into climatic conditions present at or near the time of deposition by helping to delineate changes in rainfall and oceanic circulation intensities. The fairly homogenous hemipelagic nannofossil clays and clayey nannofossil oozes collected in the upper portion of Ocean Drilling Program (ODP) Site 1242 provide a 1.4 million year sediment record from the Cocos Ridge, in relatively shallow waters of the eastern tropical Pacific Ocean, off the coast of present day Central and South America. Information about shifts in rainfall and oceanic circulation provided by this study may be helpful in understanding changes in the location and behavior of the Intertropical Convergence Zone (ITCZ), and/or other climatic factors, in this area during the Pleistocene and Holocene Epochs. Approximately 130 paired side-by-side samples were selected at approximately evenly spaced intervals throughout the uppermost 190 mcd of the core. To obtain terrigenous grain size and MARs, one set of sediment samples was subject to a five-step chemical extraction process to dissolve any oxy-hydroxy coatings, remove the biogenic carbonate and silicate components, and sieve out grains larger than 63 µm. The pre- and post-extraction weights were compared to calculate a terrigenous weight percent (%) from which the terrigenous MAR values were then calculated, with the use of linear sediment rates and dry bulk density measurements determined from shipboard ODP 1242 analyses. Magnetic fabric, or anisotropy of magnetic susceptibility (AMS), was analyzed on a KLY4S-Kappabridge using the second set of samples taken in pmag cubes. Terrigenous MAR values range between 3.1 and 10.9 g/cm2/kyr, while P' (AMS) values range between 1.004 and 1.04 SI. A distinctive trend is noted in both factors, with both exhibiting relatively high initial values that then decrease from the beginning of the

  14. A solar oven for intertropical zones: Evaluation of the cooking process

    International Nuclear Information System (INIS)

    Hernandez-Luna, G.; Huelsz, G.

    2008-01-01

    The construction and the evaluation of the cooking process of a solar oven prototype are presented, the optogeometrical design of this oven was optimized for the intertropical zone. The cooking tests demonstrated that the oven prototype, which needs only four simple movements throughout the year, is suitable to cook three basic Mexican meals: beans, nixtamal, and corncobs. The potential quantity of wood savings per year if this oven would be used to cook meals in a rural zone of Mexico is estimated

  15. Trace gas concentrations, intertropical convergence, atmospheric fronts, and ocean currents in the tropical Pacific m(Paper 8C1060)

    International Nuclear Information System (INIS)

    Wilkniss, P.E.; Rodgers, E.B.; Swinnerton, J.W.; Larson, R.E.; Lamontagne, R.A.

    1979-01-01

    Shipboard measurements of atmospheric 222 Rn, CO, and CH 4 and of dissolved CO in surface waters have been carried out in the equatorial Pacific on a cruise from Ecuador to Hawaii, Tahiti and Panama in March and April of 1974, and during transit from Los Angeles to Antarctica in November and December of 1972. The trace gas results, combined with conventional meteorological data and with satellite images from Nimbus 5 and the defense meteorological satellite project (DMSP), have provided descriptions of the intertropical convergence zones (ITCZ) near 04 0 N, 102 0 W and 03 0 N, 154 0 W in March of 1974, near 04 0 N, 86 0 W in April of 1974, and near 05 0 N, 139 0 W in November of 1972. In all cases the ITCZ seems to be located north of the south equatorial current (SEC) as shown by dissolved CO peaks in surface waters. In April of 1974 a 'second' ITCZ was observed near 01 0 S, 102 0 W just south of the SEC. A stationary front near Hawaii (20 0 N, 147 0 W) in March of 1974 was investigated. The ITCZ was marked by light shifting winds near a zone of heavy cloud cover and precipitation. In the eastern Tropical Pacific atmospheric 222 Rn increases distinctly north of the ITCZ and thus serves as an indicator for the ITCZ. CO and CH 4 do not always increase coincident with atmospheric 222 Rn. The atmospheric features of the stationary front near Hawaii are in many ways similar to those observed for the ITCZ. The front is marked by cloud cover, precipitation zone and light shifting winds. 222 Rn, CO and CH 4 increase signifantly behind the front in subsiding air which was traced back to the Asian continent. The variation of atmospheric 222 Rn, CO and CH 4 with time and geographical area over the equatorial Pacific seems to be a consequence of seasonal variations of the trade wind field and long range transport to the central Pacific from Asia and to the eastern equatorial Pacific from North and Central America

  16. Simulation of convection over the ocean in the region of the intertropical convergence zone

    Energy Technology Data Exchange (ETDEWEB)

    Levkov, L; Eppel, D; Grassl, H

    1986-01-01

    A parameterization scheme for the simulation of mid-latitude convective structures is incorporated into a three-dimensional hydrostatic mesoscale model using data from GATE 1974. The scheme gives realistic space extension and evolution time scales of tropical cloud clusters. The rainfall computed in the model agrees with the magnitude of the radar rainfall. According to the different treatment of the microphysics we have found considerable differences in the microphysical and dynamical evolution of the clouds but not considerable changes in the final mean vertical profiles after precipitation.

  17. NASA Experiment on Tropospheric-Stratospheric Water Vapor Transport in the Intertropical Convergence Zone

    Science.gov (United States)

    Page, William A.

    1982-01-01

    The following six papers report preliminary results obtained from a field experiment designed to study the role of tropical cumulo-nimbus clouds in the transfer of water vapor from the troposphere to the stratosphere over the region of Panama. The measurements were made utilizing special NOAA enhanced IR satellite images, radiosonde-ozonesondes and a NASA U-2 aircraft carrying. nine experiments. The experiments were provided by a group of NASA, NOAA, industry, and university scientists. Measurements included atmospheric humidity, air and cloud top temperatures, atmospheric tracer constituents, cloud particle characteristics and cloud morphology. The aircraft made a total of eleven flights from August 30 through September 18, 1980, from Howard Air Force Base, Panama; the pilots obtained horizontal and vertical profiles in and near convectively active regions and flew around and over cumulo-nimbus towers and through the extended anvils in the stratosphere. Cumulo-nimbus clouds in the tropics appear to play an important role in upward water vapor transport and may represent the principal source influencing the stratospheric water vapor budget. The clouds provide strong vertical circulation in the troposphere, mixing surface air and its trace materials (water vapor, CFM's sulfur compounds, etc.) quickly up to the tropopause. It is usually assumed that large scale mean motions or eddy scale motions transport the trace materials through the tropopause and into the stratosphere where they are further dispersed and react with other stratospheric constituents. The important step between the troposphere and stratosphere for water vapor appears to depend upon the processes occurring at or near the tropopause at the tops of the cumulo-nimbus towers. Several processes have been sugested: (1) The highest towers penetrate the tropopause and carry water in the form of small ice particles directly into the stratosphere. (2) Water vapor from the tops of the cumulonimbus clouds is transported somehow through the tropopause, the vapor pressure being controlled by the temperature at the tops of the clouds; the dryness of the stratosphere could be explained if most of the transport occurs in connection with very high clouds in regions with very high and cold tropopause. (3) Cumulo-nimbus anvils act as terrestrial-radiation shields allowing the ice particle temperatures near cloud tops to cool radiatively below the supersaturation point; this cooling would cause a vapor deposition on the ice particles which will settle out and thus act as water scavengers. The experiment was designed to collect information on these detailed physical processes near and above the tropopause in order to assess their importance and the role they play in controlling stratospheric water vapor humidity.

  18. Vadose zone flow convergence test suite

    Energy Technology Data Exchange (ETDEWEB)

    Butcher, B. T. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2017-06-05

    Performance Assessment (PA) simulations for engineered disposal systems at the Savannah River Site involve highly contrasting materials and moisture conditions at and near saturation. These conditions cause severe convergence difficulties that typically result in unacceptable convergence or long simulation times or excessive analyst effort. Adequate convergence is usually achieved in a trial-anderror manner by applying under-relaxation to the Saturation or Pressure variable, in a series of everdecreasing RELAxation values. SRNL would like a more efficient scheme implemented inside PORFLOW to achieve flow convergence in a more reliable and efficient manner. To this end, a suite of test problems that illustrate these convergence problems is provided to facilitate diagnosis and development of an improved convergence strategy. The attached files are being transmitted to you describing the test problem and proposed resolution.

  19. Gray Zone Legislation and Activities: Evaluating the Orchestration of Convergence Within the Gray Zone

    Science.gov (United States)

    2017-06-01

    The Agency and the Hill (Government Printing Office, 2008), 8. 16 Lowenthal, Intelligence . 17 Marshall Erwin, Covert Action: Legislative Background...military and intelligence activities within the Gray Zone and what directs their convergence. More specifically, the author analyzes the...determining convergence or divergence. In the end, classical military theory directs the convergence and divergence of military and intelligence activities

  20. Why the South Pacific Convergence Zone is diagonal

    OpenAIRE

    Van Der Wiel, Karin; Matthews, Adrian; Joshi, Manoj; Stevens, David

    2016-01-01

    During austral summer, the majority of precipitation over the Pacific Ocean is concentrated in the South Pacific Convergence Zone (SPCZ). The surface boundary conditions required to support the diagonally (northwest-southeast) oriented SPCZ are determined through a series of experiments with an atmospheric general circulation model. Continental configuration and orography do not have a significant influence on SPCZ orientation and strength. The key necessary boundary condition is the zonally ...

  1. Plankton dynamics associated with the convergence zone of a shear ...

    African Journals Online (AJOL)

    Multiple linear regression was used to determine the relationships between water quality variables and plankton abundances. Community analysis was also run on the data in order to determine community dynamics associated with frontal system convergence and downwelling. Key words: ichthyoplankton, phytoplankton, ...

  2. Mod-ϕ convergence normality zones and precise deviations

    CERN Document Server

    Féray, Valentin; Nikeghbali, Ashkan

    2016-01-01

    The canonical way to establish the central limit theorem for i.i.d. random variables is to use characteristic functions and Lévy’s continuity theorem. This monograph focuses on this characteristic function approach and presents a renormalization theory called mod-ϕ convergence. This type of convergence is a relatively new concept with many deep ramifications, and has not previously been published in a single accessible volume. The authors construct an extremely flexible framework using this concept in order to study limit theorems and large deviations for a number of probabilistic models related to classical probability, combinatorics, non-commutative random variables, as well as geometric and number-theoretical objects. Intended for researchers in probability theory, the text is carefully well-written and well-structured, containing a great amount of detail and interesting examples. .

  3. Vulnerability of intertropical littoral areas

    Science.gov (United States)

    Manighetti, Isabelle; De Wit, Rutger; Duvail, Stéphanie; Seyler, Patrick

    2017-10-01

    The coastal zone is of very high importance for human development and human wellbeing. Half of the global urban population lives in the coastal zone, where it has access to both continental and marine ecosystem services and to maritime transport. These urban populations coexist with rural and traditional coastal populations, some of which still possess good traditional ecological knowledge of the coastal ecosystems. Marine biodiversity and favourable environmental conditions sustain fisheries and aquaculture, represent a source of inspiration for humankind and provide numerous opportunities for recreation and tourism. In addition, coastal areas provide nursery functions for juvenile fish and invertebrates, which is important for the fish and crayfish stocks exploited offshore. Located at the interface between marine energy and continental processes, the coastal landscapes are dynamic environments. Nevertheless, the destruction of habitats and the increasing exploitation of the coastal zone represent serious threats to the ecosystems. Moreover, human land use and modifications in the watersheds have strong impacts on the coastal zone primarily by contributing to their pollution and nutrient over-enrichment. Damming and creation of reservoirs upstream also heavily modify the hydrology of the watersheds and often dramatically reduce the delivery of sediments to the coastal zone. In addition to these regional and local anthropogenic impacts, the coastal zone is vulnerable to global change among which sea level rise and climate change are particularly important drivers. Many coastal zones extend along giant faults and subduction zones, which makes them particularly exposed to earthquakes and tsunami hazards. Other forms of natural hazards are caused by hurricanes and cyclones that develop at sea and whose trajectories often hit the coastlines.

  4. Concentration of floating biogenic material in convergence zones

    Science.gov (United States)

    Dandonneau, Yves; Menkes, Christophe; Duteil, Olaf; Gorgues, Thomas

    Some organisms that live just below the sea surface (the neuston) are known more as a matter of curiosity than as critical players in biogeochemical cycles. The hypothesis of this work is that their existence implies that they receive some food from an upward flux of organic matter. The behaviour of these organisms and of the associated organic matter, hereafter mentioned as floating biogenic material (FBM) is explored using a global physical-biogeochemical coupled model, in which its generation is fixed to 1% of primary production, and decay rate is of the order of 1 month. The model shows that the distribution of FBM should depart rapidly from that of primary production, and be more sensitive to circulation patterns than to the distribution of primary production. It is trapped in convergence areas, where it reaches concentrations larger by a factor 10 than in divergences, thus enhancing and inverting the contrast between high and low primary productivity areas. Attention is called on the need to better understand the biogeochemical processes in the first meter of the ocean, as they may impact the distribution of food for fishes, as well as the conditions for air-sea exchange and for the interpretation of sea color.

  5. Convergence

    Science.gov (United States)

    Darcie, Thomas E.; Doverspike, Robert; Zirngibl, Martin; Korotky, Steven K.

    2005-09-01

    Call for Papers: Convergence The Journal of Optical Networking (JON) invites submissions to a special issue on Convergence. Convergence has become a popular theme in telecommunications, one that has broad implications across all segments of the industry. Continual evolution of technology and applications continues to erase lines between traditionally separate lines of business, with dramatic consequences for vendors, service providers, and consumers. Spectacular advances in all layers of optical networking-leading to abundant, dynamic, cost-effective, and reliable wide-area and local-area connections-have been essential drivers of this evolution. As services and networks continue to evolve towards some notion of convergence, the continued role of optical networks must be explored. One vision of convergence renders all information in a common packet (especially IP) format. This vision is driven by the proliferation of data services. For example, time-division multiplexed (TDM) voice becomes VoIP. Analog cable-television signals become MPEG bits streamed to digital set-top boxes. T1 or OC-N private lines migrate to Ethernet virtual private networks (VPNs). All these packets coexist peacefully within a single packet-routing methodology built on an optical transport layer that combines the flexibility and cost of data networks with telecom-grade reliability. While this vision is appealing in its simplicity and shared widely, specifics of implementation raise many challenges and differences of opinion. For example, many seek to expand the role of Ethernet in these transport networks, while massive efforts are underway to make traditional TDM networks more data friendly within an evolved but backward-compatible SDH/SONET (synchronous digital hierarchy and synchronous optical network) multiplexing hierarchy. From this common underlying theme follow many specific instantiations. Examples include the convergence at the physical, logical, and operational levels of voice and

  6. Similarity and Difference between the South Atlantic Convergence Zone and the Baiu Frontal Zone Simulated by an AGCM

    OpenAIRE

    Kozo, NINOMIYA; Frontier Research Center for Global Change, Japan Agency for Marine-Earth Science and Technology

    2007-01-01

    Features of the South Atlantic convergence zone (SACZ) and the Baiu frontal zone (BFZ) simulated by an AGCM (T106L56: a primitive equation spectral model which has 56 σ-levels and triangular spectral truncation at wave-number 106) are studied. The 24-year integration, from 1979 to 2002, by the model constrained by observed sea-surface temperature and sea-ice distribution, is used for this study. The detailed analysis is made for the typical case of SACZ and BFZ selected from data in 1985-1996...

  7. Convergence

    DEFF Research Database (Denmark)

    Madsen, Ole Brun; Nielsen, Jens Frederik Dalsgaard; Schiøler, Henrik

    2002-01-01

    Convergence trends between the WAN Internet area, characterized by best effort service provision, and the real time LAN domain, with requirements for guaranteed services, are identified and discussed. A bilateral evolution is identified, where typical bulk service applications from WAN, such as m......Convergence trends between the WAN Internet area, characterized by best effort service provision, and the real time LAN domain, with requirements for guaranteed services, are identified and discussed. A bilateral evolution is identified, where typical bulk service applications from WAN...... with the emergence of remote service provision, such as supervision and control of decentralized heating facilities and wind based electrical power production. The reliability issue is addressed from a structural viewpoint, where the concept of Structural QoS (SQoS) is defined to support reliability modelling...

  8. Convergence

    DEFF Research Database (Denmark)

    Prasad, Ramjee

    2009-01-01

    This paper presents the main conclusions which can be drawn from the discussions on Future Communication Systems and lessons on Unpredictable Future of Wireless Communication Systems. Future systems beyond the third generation are already under discussions in international bodies, such as ITU, WW...... and R&D programmes worldwide. The incoming era is characterized by the convergence of networks and access technology and the divergence of applications. Future mobile communication systems should bring something more than only faster data or wireless internet access....

  9. Convergence

    Science.gov (United States)

    Darcie, Thomas E.; Doverspike, Robert; Zirngibl, Martin; Korotky, Steven K.

    2005-01-01

    .p {padding-bottom:6px} Call for Papers: Convergence Guest Editors: Thomas E. Darcie, University of Victoria Robert Doverspike, AT&T Martin Zirngibl, Lucent Technologies Coordinating Associate Editor: Steven K. Korotky, Lucent Technologies The Journal of Optical Networking (JON) invites submissions to a special issue on Convergence. Convergence has become a popular theme in telecommunications, one that has broad implications across all segments of the industry. Continual evolution of technology and applications continues to erase lines between traditionally separate lines of business, with dramatic consequences for vendors, service providers, and consumers. Spectacular advances in all layers of optical networking-leading to abundant, dynamic, cost-effective, and reliable wide-area and local-area connections-have been essential drivers of this evolution. As services and networks continue to evolve towards some notion of convergence, the continued role of optical networks must be explored. One vision of convergence renders all information in a common packet (especially IP) format. This vision is driven by the proliferation of data services. For example, time-division multiplexed (TDM) voice becomes VoIP. Analog cable-television signals become MPEG bits streamed to digital set-top boxes. T1 or OC-N private lines migrate to Ethernet virtual private networks (VPNs). All these packets coexist peacefully within a single packet-routing methodology built on an optical transport layer that combines the flexibility and cost of data networks with telecom-grade reliability. While this vision is appealing in its simplicity and shared widely, specifics of implementation raise many challenges and differences of opinion. For example, many seek to expand the role of Ethernet in these transport networks, while massive efforts are underway to make traditional TDM networks more data friendly within an evolved but backward-compatible SDH/SONET (synchronous digital hierarchy and

  10. Quaternary tectonic evolution of the Pamir-Tian Shan convergence zone, Northwest China

    Science.gov (United States)

    Thompson Jobe, Jessica Ann; Li, Tao; Chen, Jie; Burbank, Douglas W.; Bufe, Aaron

    2017-12-01

    The Pamir-Tian Shan collision zone in the western Tarim Basin, northwest China, formed from rapid and ongoing convergence in response to the Indo-Eurasian collision. The arid landscape preserves suites of fluvial terraces crossing structures active since the late Neogene that create fault and fold scarps recording Quaternary deformation. Using geologic and geomorphic mapping, differential GPS surveys of deformed terraces, and optically stimulated luminescence dating, we create a synthesis of the active structures that delineate the timing, rate, and migration of Quaternary deformation during ongoing convergence. New deformation rates on eight faults and folds, when combined with previous studies, highlight the spatial and temporal patterns of deformation within the Pamir-Tian Shan convergence zone during the Quaternary. Terraces spanning 130 to 8 ka record deformation rates between 0.1 and 5.6 mm/yr on individual structures. In the westernmost Tarim Basin, where the Pamir and Tian Shan are already juxtaposed, the fastest rates occur on actively deforming structures at the interface of the Pamir-Tian Shan orogens. Farther east, as the separation between the Pamir-Tian Shan orogens increases, the deformation has not been concentrated on a single structure, but rather has been concurrently distributed across a zone of faults and folds in the Kashi-Atushi fold-and-thrust belt and along the NE Pamir margin, where shortening rates vary on individual structures during the Quaternary. Although numerous structures accommodate the shortening and the locus of deformation shifts during the Quaternary, the total shortening across the western Tarim Basin has remained steady and approximately matches the current geodetic rate of 6-9 mm/yr.

  11. Spatial evolution of Zagros collision zone in Kurdistan, NW Iran: constraints on Arabia-Eurasia oblique convergence

    Science.gov (United States)

    Sadeghi, Shahriar; Yassaghi, Ali

    2016-04-01

    Stratigraphy, detailed structural mapping and a crustal-scale cross section across the NW Zagros collision zone provide constraints on the spatial evolution of oblique convergence of the Arabian and Eurasian plates since the Late Cretaceous. The Zagros collision zone in NW Iran consists of the internal Sanandaj-Sirjan, Gaveh Rud and Ophiolite zones and the external Bisotoun, Radiolarite and High Zagros zones. The Main Zagros Thrust is the major structure of the Zagros suture zone. Two stages of oblique deformation are recognized in the external part of the NW Zagros in Iran. In the early stage, coexisting dextral strike-slip and reverse dominated domains in the Radiolarite zone developed in response to deformation partitioning due to oblique convergence. Dextral-reverse faults in the Bisotoun zone are also compatible with oblique convergence. In the late stage, deformation partitioning occurred during southeastward propagation of the Zagros orogeny towards its foreland resulting in synchronous development of orogen-parallel strike-slip and thrust faults. It is proposed that the first stage was related to Late Cretaceous oblique obduction, while the second stage resulted from Cenozoic collision. The Cenozoic orogen-parallel strike-slip component of Zagros oblique convergence is not confined to the Zagros suture zone (Main Recent Fault) but also occurred in the external part (Marekhil-Ravansar fault system). Thus, it is proposed that oblique convergence of Arabian and Eurasian plates in Zagros collision zone initiated with oblique obduction in the Late Cretaceous followed by oblique collision in the late Tertiary, consistent with global plate reconstructions.

  12. Spatial evolution of Zagros collision zone in Kurdistan - NW Iran, constraints for Arabia-Eurasia oblique convergence

    Science.gov (United States)

    Sadeghi, S.; Yassaghi, A.

    2015-09-01

    Stratigraphy, detailed structural mapping and crustal scale cross section of the NW Zagros collision zone evolved during convergence of the Arabian and Eurasian plates were conducted to constrain the spatial evolution of the belt oblique convergence since Late Cretaceous. Zagros orogeny in NW Iran consists of the Sanandaj-Sirjan, Gaveh Rud and ophiolite zones as internal, and Bisotoun, Radiolarite and High Zagros zones as external parts. The Main Zagros Thrust is known as major structures of the Zagros suture zone. Two stages of deformation are recognized in the external parts of Zagros. In the early stage, presence of dextrally deformed domains beside the reversely deformed domains in the Radiolarite zone as well as dextral-reverse faults in both Bisotoun and Radiolarite zones demonstrates partitioning of the dextral transpression. In the late stage, southeastward propagation of the Zagros orogeny towards its foreland resulted in synchronous development of orogen-parallel strike-slip and pure thrust faults. It is proposed that the first stage related to the late Cretaceous oblique obduction, and the second stage is resulted from Cenozoic collision. Cenozoic orogen-parallel strike-slip component of Zagros oblique faulting is not confined to the Zagros suture zone (Main Recent) but also occurred in the more external part (Marekhil-Ravansar fault system). Thus, it is proposed that oblique convergence of Arabia-Eurasia plates occurred in Zagros collision zone since the Late Cretaceous.

  13. Role of the convergence zone over West Africa in controlling Saharan mineral dust load and transport in the boreal summer

    Directory of Open Access Journals (Sweden)

    Owen M. Doherty

    2014-07-01

    Full Text Available During summer, large amounts of mineral dust are emitted and transported from North Africa over the tropical North Atlantic towards the Caribbean with the exact quantity varying greatly from year to year. Much effort has been made to explain the variability of summer season mineral dust load, for example, by relating dust variability to teleconnection indices such as ENSO and the NAO. However, only weak relationships between such climate indices and the abundance of mineral dust have been found. In this work, we demonstrate the role of the near-surface convergence zone over West Africa in controlling dust load and transport of mineral dust. We apply the ‘Center of Action’ approach to obtain indices that quantify the movement and strength of the convergence zone using NCEP/NCAR Reanalysis data. The latitudinal position of the convergence zone is significantly correlated with the quantity of mineral dust at Barbados over the period 1965–2003 (r=−0.47. A southward displacement of the convergence zone is associated with both increased near-surface flow and decreased precipitation over the dust source regions of the southern Saharan desert, Sahel and Lake Chad. This in turn reduces soil moisture and vegetation, furthering the potential for dust emission. In contrast, the intensity of the convergence zone is not correlated with dust concentration at Barbados. We conclude that the coupling of changes in near-surface winds with changes in precipitation in source regions driven by a southward movement of the convergence zone most directly influence dust load at Barbados and over the tropical North Atlantic during summer.

  14. Distribution and production of plankton communities in the subtropical convergence zone of the Sargasso Sea. II. Protozooplankton and copepods

    DEFF Research Database (Denmark)

    Andersen, Nikolaj G.; Nielsen, Torkel Gissel; Jakobsen, Hans Henrik

    2011-01-01

    the potential reasons why Atlantic eels Anguilla spp. use this area for spawning, we investigated the distribution and productivity of the zooplankton community across the Subtropical Convergence Zone (STCZ) in the Sargasso Sea in March and April 2007. The vertical and horizontal distributions of protozoans...

  15. Characterization of the variability of the South Pacific Convergence Zone using satellite and reanalysis wind products

    Science.gov (United States)

    Kidwell, Autumn; Lee, Tong; Jo, Young-Heon; Yan, Xiao-hai

    2016-04-01

    The South Pacific Convergence Zone (SPCZ), the largest rain band worldwide during austral summer, is important to atmospheric circulation (including cyclone genesis) and ocean circulation. Previous studies of the SPCZ have focused on parameters such as outgoing longwave radiation or precipitation. However, wind convergence is fundamental causing the variations of these parameters. In this study, the SPCZ variability is examined using ocean surface wind products derived from NASA's QuickSCAT (1999-2009) and ESA's ASCAT (2007 onward) satellite scatterometers and ERA-Interim atmospheric reanalysis (1981 onward). From these products, indices were developed to characterize the SPCZ strength, area, and centroid location. Excellent agreement is found in terms of the temporal variations of the indices derived from the satellites and reanalysis wind products, despite some small differences in the time-mean SPCZ strength. The SPCZ strength, area, and centroid latitude have a dominant seasonal cycle. In contrast, the SPCZ centroid longitude is dominated by intraseasonal variability due to the influence by the Madden-Julian Oscillation. The SPCZ indices are all correlated with El Niño-Southern Oscillation indices. Interannual and intraseasonal variations of SPCZ strength during strong El Niño are approximately twice as large as the respective seasonal variations. SPCZ strength depends more on the intensity of El Niño rather than the central- vs. eastern-Pacific type. The longer ERA-Interim product is also used to examine decadal variations of the SPCZ indices. The change from positive to negative Pacific Decadal Oscillation phase around 1999 resulted in a westward shift of the SPCZ centroid longitude, much smaller interannual swing in centroid latitude, and a decrease in SPCZ area. This study improves the understanding of the variations of the SPCZ on multiple time scales and reveals the variations of SPCZ strength not reported previously. The diagnostics analyses can be

  16. Aqua-planet simulations of the formation of the South Atlantic convergence zone

    Science.gov (United States)

    Nieto Ferreira, Rosana; Chao, Winston C.

    2013-01-01

    The impact of Amazon Basin convection and cold fronts on the formation and maintenance of the South Atlantic convergence zone (SACZ) is studied using aqua-planet simulations with a general circulation model. In the model, a circular patch of warm sea-surface temperature (SST) is used to mimic the effect of the Amazon Basin on South American monsoon convection. The aqua-planet simulations were designed to study the effect of the strength and latitude of Amazon Basin convection on the formation of the SACZ. The simulations indicate that the strength of the SACZ increases as the Amazon convection intensifies and is moved away from the equator. Of the two controls studied here, the latitude of the Amazon convection exerts the strongest effect on the strength of the SACZ. An analysis of the synoptic-scale variability in the simulations shows the importance of frontal systems in the formation of the aqua-planet SACZ. Composite time series of frontal systems that occurred in the simulations show that a robust SACZ occurs when fronts penetrate into the subtropics and become stationary there as they cross eastward of the longitude of the Amazon Basin. Moisture convergence associated with these frontal systems produces rainfall not along the model SACZ region and along a large portion of the northern model Amazon Basin. Simulations in which the warm SST patch was too weak or too close to the equator did not produce frontal systems that extended into the tropics and became stationary, and did not form a SACZ. In the model, the SACZ forms as Amazon Basin convection strengthens and migrates far enough southward to allow frontal systems to penetrate into the tropics and stall over South America. This result is in agreement with observations that the SACZ tends to form after the onset of the monsoon season in the Amazon Basin.

  17. Radially converging tracer test in a low-angle fracture zone at the Finnsjoen site, central Sweden. The fracture zone project - phase 3

    International Nuclear Information System (INIS)

    Gustafsson, E.; Nordqvist, R.

    1993-10-01

    The performance and results of a radially converging tracer test in a low-angle major fracture zone in crystalline rock are described. The extensive, about 100 m thick, zone 2 was encountered by means of borehole investigations at depths ranging from 100 to 250 metres at the Finnsjon site, central eastern Sweden. The zone studied (zone 2) consists of highly conductive, metre thick interconnected minor shear and fracture zones (sub-zones) with low conductive rock in between. The objective of the tracer test was primarily to determine flow and transport characteristics in a major fracture zone. Secondly new equipment, experimental design and methods of interpretation were developed, tested and improved. The converging flow field was created by pumping in a central borehole from a packed-off interval enclosing the whole thickness of zone 2. Tracer breakthrough was registered from all nine injection points, with first arrivals ranging from 24 to 3200 hours. Evaluated flow and transport parameters included; flow porosity, dispersivity, flow wetted surface, fracture aperture and hydraulic conductivity in fracture flow paths. Directional variations were found in the flow and transport parameters determined, which is concluded to be due to heterogeneity and/or anisotropy. This conditions is more pronounced at depth in zone 2. The results from the tracer test also clearly show that the upper boundary of zone 2 is highly conductive and consistent over hundreds of metres. Within zone 2, and between upper and lower margins, interconnected discrete minor shear and fracture zones (sub-zones) constitute flow paths of considerable variable residence times. The dispersion within the sub-zones of zone 2, expressed as Peclet numbers ranged from 16 to 40. Flow porosity was determined to be 0.001-0.05 in the upper sub-zone and 0.01-0.1 in the intermediate and lower ones and flow wetted surface area per volume of rock was calculated to be within 1-92 m 2 /m 3 . 68 refs, 61 figs, 40 tabs

  18. Characterization of the variability of the South Pacific Convergence Zone using satellite and reanalysis wind product

    Science.gov (United States)

    Lee, T.; Kidwell, A. N.; Jo, Y. H.; Yan, X. H.

    2016-02-01

    The variability of the South Pacific Convergence Zone (SPCZ) is evaluated using ocean surface wind products derived from the QuickSCAT satellite scatterometer for the period of 1999-2009and ERA-Interim atmospheric reanalysis for the period of 1981-2014. From these products, indices were developed to represent the SPCZ strength, area, and centroid location. Excellent agreement is found between the indices derived from the two wind products during the QuikSCAT period in terms of the spatio-temporal structures of the SPCZ. The longer ERA-Interim product is then used to study the variations of SPCZ properties on intraseasonal, seasonal, interannual, and decadal time scales. The SPCZ strength, area, and centroid latitude have a dominant seasonal cycle. In contrast, the SPCZ centroid longitude is dominated by intraseasonal variability due to the influence by the Madden-Julian Oscillation. The SPCZ indices are all correlated with El Niño-Southern Oscillation indices. Interannual and intraseasonal variations of SPCZ strength during strong El Niño are approximately twice as large as the respective seasonal variations. SPCZ strength depends more on the intensity of El Niño rather than the central- vs. eastern-Pacific type. The change from positive to negative Pacific Decadal Oscillation phase around 1999 results in a westward shift of the SPCZ centroid longitude, much smaller interannual swing in centroid latitude, and a decrease in SPCZ area. This study improves the understanding of the variations of the SPCZ on multiple time scales and reveals the variations of SPCZ strength not reported previously. The diagnostics analyses can be used to evaluate climate models.

  19. ENSO influence on the interannual variability of the Red Sea convergence zone and associated rainfall

    KAUST Repository

    Dasari, Hari Prasad

    2017-07-18

    The Red Sea convergence zone (RSCZ) is formed by opposite surface winds blowing from northwest to southeast directions at around 18°-19°N between October and January. A reverse-oriented, low-level monsoon trough at 850hPa, known as the Red Sea trough (RST), transfers moisture from the southern Red Sea to RSCZ. The positions of the RSCZ and RST and the intensity of the RST have been identified as important factors in modulating weather and climatic conditions across the Middle East. Here, we investigate the influence of the El Niño southern oscillation (ENSO) on the interannual variability of RSCZ, RST, and regional rainfall during winter months. Our results indicate that El Niño (warm ENSO phase) favours a shift of the RSCZ to the north and a strengthening of the RST in the same direction. Conversely, during November and December of La Niña periods (cold ENSO phase), the RSCZ shift to the south and the RST strengthens in the same direction. During El Niño periods, southeasterly wind speeds increase (20-30%) over the southern Red Sea and northwesterly wind speeds decrease (10-15%) over the northern Red Sea. Noticeable increases in the number of rainy days and the intensity of rain events are observed during El Niño phases. These increases are associated with colder than normal air intrusion at lower levels from the north combined with warm air intrusion from the south over the RSCZ. Our analysis suggests that during El Niño winters, warmer sea surface temperatures and higher convective instability over the Red Sea favour local storms conditions and increase rainfall over the Red Sea and adjoining regions.

  20. A viscoplastic shear-zone model for deep (15-50 km) slow-slip events at plate convergent margins

    Science.gov (United States)

    Yin, An; Xie, Zhoumin; Meng, Lingsen

    2018-06-01

    A key issue in understanding the physics of deep (15-50 km) slow-slip events (D-SSE) at plate convergent margins is how their initially unstable motion becomes stabilized. Here we address this issue by quantifying a rate-strengthening mechanism using a viscoplastic shear-zone model inspired by recent advances in field observations and laboratory experiments. The well-established segmentation of slip modes in the downdip direction of a subduction shear zone allows discretization of an interseismic forearc system into the (1) frontal segment bounded by an interseismically locked megathrust, (2) middle segment bounded by episodically locked and unlocked viscoplastic shear zone, and (3) interior segment that slips freely. The three segments are assumed to be linked laterally by two springs that tighten with time, and the increasing elastic stress due to spring tightening eventually leads to plastic failure and initial viscous shear. This simplification leads to seven key model parameters that dictate a wide range of mechanical behaviors of an idealized convergent margin. Specifically, the viscoplastic rheology requires the initially unstable sliding to be terminated nearly instantaneously at a characteristic velocity, which is followed by stable sliding (i.e., slow-slip). The characteristic velocity, which is on the order of <10-7 m/s for the convergent margins examined in this study, depends on the (1) effective coefficient of friction, (2) thickness, (3) depth, and (4) viscosity of the viscoplastic shear zone. As viscosity decreases exponentially with temperature, our model predicts faster slow-slip rates, shorter slow-slip durations, more frequent slow-slip occurrences, and larger slow-slip magnitudes at warmer convergent margins.

  1. Interannual variability of the South Pacific Convergence Zone and implications for tropical cyclone genesis

    Energy Technology Data Exchange (ETDEWEB)

    Vincent, Emmanuel M. [IRD/UPMC/CNRS/MNHN, Laboratoire d' Oceanographie et du Climat: Experimentation et Approches Numeriques (LOCEAN), Paris (France); UPMC, LOCEAN/IPSL, Paris Cedex 05 (France); Lengaigne, Matthieu [IRD/UPMC/CNRS/MNHN, Laboratoire d' Oceanographie et du Climat: Experimentation et Approches Numeriques (LOCEAN), Paris (France); National Institute of Oceanography, Goa (India); Menkes, Christophe E. [IRD/UPMC/CNRS/MNHN, Laboratoire d' Oceanographie et du Climat: Experimentation et Approches Numeriques (LOCEAN), Paris (France); Institut de Recherche pour le Developpement, Noumea (New Caledonia); Jourdain, Nicolas C. [Institut de Recherche pour le Developpement, Noumea (New Caledonia); Marchesiello, Patrick [Institut de Recherche pour le Developpement, Noumea (New Caledonia); CNES/CNRS/UPS/IRD, Laboratoire d' Etudes en Geophysique et Oceanographie Spatiale (LEGOS), Toulouse (France); Madec, Gurvan [IRD/UPMC/CNRS/MNHN, Laboratoire d' Oceanographie et du Climat: Experimentation et Approches Numeriques (LOCEAN), Paris (France); National Oceanographic Centre, Southampton (United Kingdom)

    2011-05-15

    The interannual variability of the South Pacific Convergence Zone (SPCZ) and its influence on tropical cyclone (TC) genesis in the South Pacific are investigated using observations and ERA40 reanalysis over the 1979-2002 period. In austral summer, the SPCZ displays four typical structures at interannual timescales. The first three are characterized by a diagonal orientation of the SPCZ and account for 85% of the summer seasons. One is close to climatology and the other two exhibit a 3 northward or southward departure from the SPCZ climatological position. In contrast, the fourth one, that only encompasses three austral summer seasons (the extreme 1982/1983 and 1997/1998 El Nino events and the moderate 1991/1992 El Nino event), displays very peculiar behaviour where the SPCZ largely departs from its climatological position and is zonally oriented. Variability of the western/central Pacific equatorial sea surface temperature (SST) is shown to modulate moisture transport south of the equator, thereby strongly constraining the location of the SPCZ. The SPCZ location is also shown to strongly modulate the atmospheric circulation variability in the South Pacific with specific patterns for each class. However, independently of its wide year-to-year excursions, the SPCZ is always collocated with the zero relative vorticity at low levels while the maximum vorticity axis lies 6 to the south of the SPCZ position. This coherent atmospheric organisation in the SPCZ region is shown to constrain tropical cyclogenesis to occur preferentially within 10 south of the SPCZ location as this region combines all the large-scale atmospheric conditions that favour the breeding of TCs. This analysis also reveals that cyclogenesis in the central Pacific (in the vicinity of French Polynesia) only occurs when the SPCZ displays a zonal orientation while this observation was previously attributed to El Nino years in general. Different characteristics of El Nino Southern Oscillation (ENSO

  2. Mechanisms and Attribution of Changes in Austral Summer Precipitation Related to the South Atlantic Convergence Zone

    Science.gov (United States)

    Zilli, Marcia Terezinha

    Austral summer (DJF) precipitation over tropical South America (SA) is characterized by the South American Monsoon System (SAMS) and the South Atlantic Convergence Zone (SACZ). The increase in atmospheric temperature and water vapor content over the SA during the last decades of the 20 th century could affect the duration and amplitude of the SAMS and the intensity of the SACZ. This research examines the spatial variability of precipitation trends over SE Brazil, focusing on the SACZ. More specifically, this study investigates trends in precipitation over Southeastern Brazil (SE Brazil) and examines changes in the position and intensity of the SACZ. SE Brazil is the most densely populated region in the country with a large portion of this population living in urban centers. The SACZ is important for agriculture and water supply for millions of people. One of the main goals of this research is to identify mechanisms associated with the observed changes in the characteristics of the SACZ during the last three decades of the 20th century, and examine the relative contribution of natural and anthropogenic forcing to precipitation trends. The first chapter investigates the pattern of spatial variability of precipitation trends over the coastal region of SE Brazil. This study shows that over the southern portion of the study area, precipitation is increasing due to the increase in the frequency and intensity of extreme events. Over the northern portion of the area, while the intensity of extreme events is increasing, the number of precipitating days is decreasing. This spatial pattern of precipitation trends suggests a poleward shift of the SACZ, which is investigated in the second chapter. Chapter 2 focuses on the underlying mechanisms associated with changes in precipitation intensity related to the position of the SACZ. Decadal variations in the mean state of the atmosphere suggest that the observed changes in precipitation over SE Brazil are associated with a

  3. Distribution and production of plankton communities in the subtropical convergence zone of the Sargasso Sea. I. Phytoplankton and bacterioplankton

    DEFF Research Database (Denmark)

    Riemann, Lasse; Nielsen, Torkel Gissel; Kragh, Theis

    2011-01-01

    Elevated levels of biomass and productivity are often associated with ocean frontal systems. The Subtropical Convergence Zone (STCZ) in the southern Sargasso Sea shows pronounced and stable thermal fronts, but little is known about the ecological consequences of these hydrographic features....... With the aim of improving the understanding of physical and lower trophic level processes in the area, we carried out field studies of physical, chemical and biological characteristics along 3 transects crossing thermal fronts associated with the STCZ in March to April 2007. Thermal and chemical stratification...

  4. Thoughts on Multi-sphere Study in the Indo-Pacific Convergent Zone

    Science.gov (United States)

    Wang, F.

    2016-12-01

    Interactions of the ocean with other components of the earth system, such as atmosphere, lithosphere, and biosphere are the front and hotspot of the ocean and earth sciences. In the Indonesian Archipelago and adjacent western Pacific and eastern Indian Oceans, both the upper oceanic circulation and lower atmospheric circulation convergent and consequently enhance the fresh water and heat fluxes, affecting the East Asian and global climate. This region is considered as the world's center of marine bio-diversity and sediment discharge, as well as the collision center of the Eurasian, Indian and Pacific plates. Why and how the energy and material of multiple spheres convergent toward the region are important scientific issues on the front of earth system science and marine sciences, and need to be investigated through international cooperation.

  5. Convergence of tree water use within an arid-zone woodland.

    Science.gov (United States)

    O'Grady, A P; Cook, P G; Eamus, D; Duguid, A; Wischusen, J D H; Fass, T; Worldege, D

    2009-07-01

    We examined spatial and temporal patterns of tree water use and aspects of hydraulic architecture in four common tree species of central Australia--Corymbia opaca, Eucalyptus victrix, E. camaldulensis and Acacia aneura--to better understand processes that constrain water use in these environments. These four widely distributed species occupy contrasting niches within arid environments including woodlands, floodplains and riparian environments. Measurements of tree water use and leaf water potential were made at two sites with contrasting water table depths during a period of high soil water availability following summer rainfall and during a period of low soil water availability following 7 months of very little rainfall during 2007. There were significant differences in specific leaf area (SLA), sapwood area to leaf area ratios and sapwood density between species. Sapwood to leaf area ratio increased in all species from April to November indicating a decline in leaf area per unit sapwood area. Despite very little rainfall in the intervening period three species, C. opaca, E. victrix and E. camaldulensis maintained high leaf water potentials and tree water use during both periods. In contrast, leaf water potential and water use in the A. aneura were significantly reduced in November compared to April. Despite contrasting morphology and water use strategies, we observed considerable convergence in water use among the four species. Wood density in particular was strongly related to SLA, sapwood area to leaf area ratios and soil to leaf conductance, with all four species converging on a common relationship. Identifying convergence in hydraulic traits can potentially provide powerful tools for scaling physiological processes in natural ecosystems.

  6. Convergent margin structure and tectonics of the Java subduction zone (105°E-122°E)

    Science.gov (United States)

    Kopp, H.; Barckhausen, U.; Djajadihardja, Y.; Engels, M.; Flueh, E. R.; Hindle, D. A.; Lueschen, E.; Mueller, C.; Planert, L.; Reichert, C. J.; Shulgin, A. A.; Wittwer, A.

    2009-12-01

    The Java margin is the site of oceanic subduction of the Indo-Australian plate underneath the Indonesian archipelago. Data from a suite of geophysical experiments conducted between 1997-2006 using RV SONNE as platform include seismic and seismological studies, potential field measurements and high-resolution seafloor bathymetry mapping. Tomographic inversions provide an image of the ongoing deformation of the forearc and the deep subsurface. We investigate the role of various key mechanisms that shape the first-order features characterizing the present margin architecture. Our results show a high variability in subduction zone processes along the Java margin, ranging from accretionary subduction to erosive processes to zero-budget mass transfer. These variations are closely linked to changes in character of the incoming plate. Off Western Java (105°E -109°E), near-full accretion of the trench sediment fill is associated with a well-developed accretionary prism fronting a 4 km deep forearc basin. The Central Java segment (109°E -115°E) experiences the collision of an oceanic plateau dotted with numerous seamounts, causing large-scale uplift of the forearc, coupled with erosion of the frontal prism and correlated mass wasting processes. Intense deformation of the forearc basin results from thrusting and compressional forces. In the neighbouring segment farther to the east (115°E-119°E), the lack of significant sediment input to the trench supports the notion that recycling of upper plate material in the forearc sustains the massive outer high observed here adjacent to a mature forearc basin. The incoming oceanic plate of the Argo Abyssal plain is devoid of a sediment drape and the original spreading fabric overprinted by bending-related faulting near the trench shape its morphology. The transition zone from the Java margin to the Banda Arc (119°E-122°E) experiences the early stages of continent-island arc collision associated with the convergence of the

  7. Diapir versus along-channel ascent of crustal material during plate convergence: constrained by the thermal structure of subduction zones

    Science.gov (United States)

    Liu, M. Q.; Li, Z. H.

    2017-12-01

    Crustal rocks can be subducted to mantle depths, interact with the mantle wedge, and then exhume to the crustal depth again, which is generally considered as the mechanism for the formation of ultrahigh-pressure metamorphic rocks in nature. The crustal rocks undergo dehydration and melting at subarc depths, giving rise to fluids that metasomatize and weaken the overlying mantle wedge. There are generally two ways for the material ascent from subarc depths: one is along subduction channel; the other is through the mantle wedge by diapir. In order to study the conditions and dynamics of these contrasting material ascent modes, systematic petrological-thermo-mechanical numerical models are constructed with variable thicknesses of the overriding and subducting continental plates, ages of the subducting oceanic plate, as well as the plate convergence rates. The model results suggest that the thermal structures of subduction zones control the thermal condition and fluid/melt activity at the slab-mantle interface in subcontinental subduction channels, which further strongly affect the material transportation and ascent mode. Thick overriding continental plate and low-angle subduction style induced by young subducting oceanic plate both contribute to the formation of relatively cold subduction channels with strong overriding mantle wedge, where the along-channel exhumation occurs exclusively to result in the exhumation of HP-UHP metamorphic rocks. In contrast, thin overriding lithosphere and steep subduction style induced by old subducting oceanic plate are the favorable conditions for hot subduction channels, which lead to significant hydration and metasomatism, melting and weakening of the overriding mantle wedge and thus cause the ascent of mantle wedge-derived melts by diapir through the mantle wedge. This may corresponds to the origination of continental arc volcanism from mafic to ultramafic metasomatites in the bottom of the mantle wedge. In addition, the plate

  8. Influence of increasing convergence obliquity and shallow slab geometry onto tectonic deformation and seismogenic behavior along the Northern Lesser Antilles zone

    Science.gov (United States)

    Laurencin, M.; Graindorge, D.; Klingelhoefer, F.; Marcaillou, B.; Evain, M.

    2018-06-01

    In subduction zones, the 3D geometry of the plate interface is one of the key parameters that controls margin tectonic deformation, interplate coupling and seismogenic behavior. The North American plate subducts beneath the convex Northern Lesser Antilles margin. This convergent plate boundary, with a northward increasing convergence obliquity, turns into a sinistral strike-slip limit at the northwestern end of the system. This geodynamic context suggests a complex slab geometry, which has never been imaged before. Moreover, the seismic activity and particularly the number of events with thrust focal mechanism compatible with subduction earthquakes, increases northward from the Barbuda-Anguilla segment to the Anguilla-Virgin Islands segment. One of the major questions in this area is thus to analyze the influence of the increasing convergence obliquity and the slab geometry onto tectonic deformation and seismogenic behavior of the subduction zone. Based on wide-angle and multichannel reflection seismic data acquired during the Antithesis cruises (2013-2016), we decipher the deep structure of this subduction zone. Velocity models derived from wide-angle data acquired across the Anegada Passage are consistent with the presence of a crust of oceanic affinity thickened by hotspot magmatism and probably affected by the Upper Cretaceous-Eocene arc magmatism forming the 'Great Arc of the Caribbean'. The slab is shallower beneath the Anguilla-Virgin Islands margin segment than beneath the Anguilla-Barbuda segment which is likely to be directly related to the convex geometry of the upper plate. This shallower slab is located under the forearc where earthquakes and partitioning deformations increase locally. Thus, the shallowing slab might result in local greater interplate coupling and basal friction favoring seismic activity and tectonic partitioning beneath the Virgin Islands platform.

  9. Species composition and diversity of fish larvae in the Subtropical Convergence Zone of the Sargasso Sea from morphology and DNA barcoding

    DEFF Research Database (Denmark)

    Ayala, Daniel Jiro; Munk, Peter; Riemann, Lasse

    2016-01-01

    . In order to evaluate spatial variability of larval fish in the region, we examined species diversity, composition and abundances at eight stations in the Subtropical Convergence Zone (STCZ) using morphological identification and DNA barcoding. From a total of approximately 3500 specimens collected...... of the strong environmental gradients. Common eel species were concentrated between the fronts whereas common myctophids were of highest abundance at the outer edges of the fronts. The abundances of most species were generally enhanced in the vicinity of the fronts. The use of combined morphological and DNA-barcoding...

  10. Imaging the deep structures of the convergent plates along the Ecuadorian subduction zone through receiver function analysis

    Science.gov (United States)

    Galve, A.; Charvis, P.; Regnier, M. M.; Font, Y.; Nocquet, J. M.; Segovia, M.

    2017-12-01

    The Ecuadorian subduction zone was affected by several large M>7.5 earthquakes. While we have low resolution on the 1942, 1958 earthquakes rupture zones extension, the 2016 Pedernales earthquake, that occurs at the same location than the 1942 earthquake, give strong constraints on the deep limit of the seismogenic zone. This downdip limit is caused by the onset of plasticity at a critical temperature (> 350-450 °C for crustal materials, or serpentinized mantle wedge, and eventually > 700 °C for dry mantle). However we still don't know exactly where is the upper plate Moho and therefore what controls the downdip limit of Ecuadorian large earthquakes seismogenic zone. For several years Géoazur and IG-EPN have maintained permanent and temporary networks (ADN and JUAN projects) along the margin to register the subduction zone seismological activity. Although Ecuador is not a good place to perform receiver function due to its position with respect to the worldwide teleseismic sources, the very long time deployment compensate this issue. We performed a frequency dependent receiver function analysis to derive (1) the thickness of the downgoing plate, (2) the interplate depth and (3) the upper plate Moho. These constraints give the frame to interpretation on the seismogenic zone of the 2016 Pedernales earthquake.

  11. Vulnerability of inter-tropical littoral areas. Preface

    Science.gov (United States)

    Charvis, Philippe; Gubert, Flore; Ménard, Frédéric

    2017-10-01

    The coastal area is defined as the interface between land and sea. It is a transition zone where land is affected by its proximity to the sea, and the coastal sea is affected by its proximity to the land. Its components are diverse and include river deltas, coastal plains, wetlands, beaches and dunes, reefs, mangrove forests, lagoons, and other coastal features. Coastal areas contribute to a small proportion of the total land area in the Earth system, but they provide a wide variety of ecosystem services (e.g., food through fish production, sand mining, flooding and erosion protection, recreational benefits, etc.) and are home to a large and growing proportion of the world's population.

  12. Focused Fluid Flow along Convergent Plate Boundaries - Deriving Flow Rates along Faults from Local Upwarping of the Base of the Gas Hydrate Stability Zone

    Science.gov (United States)

    Kunath, P.; Chi, W. C.; Liu, C. S.

    2017-12-01

    Convergent plate boundaries provide the ideal opportunity to examine the interactions of deformation, fluid flow and gas hydrate stability. However, there are still processes and parameters that remain unclear or scarce. This may be in part due to the fact that in situ determination of fluid flow rate is very difficult. Here, we present a newly developed 2-D hydrothermal model for (1) simulating the steady state, thermal effect of forced heat advection along a thin and shallow dipping fault and (2) quantifying fluid velocities required to deliver a thermal anomalies manifested at the bottom-simulating reflector (BSR) at its intersection with the fault zone. Assuming the horizontal thermal conduction is negligible, we derive our model using only a few crucial parameters: (a) the thermal conductivity structure between seafloor and fault; (b) the temperature at BSR depth and the seafloor; (c) fluid flow rate; (d) geometry of the fault conduit, including depth and thickness. Temperature disturbance is then described as a function of Peclet number and of the dip of the fault. Application of our model to Site 892 at Cascadia accretionary wedge (ODP Leg 146), where borehole data provide excellent thermal constraints on the hydrology, shows consistent results. By comparing the temperatures derived at the BSRs with the temperature field of our model, the results demonstrate that the temperature discrepancy is about 0 - 0.5 oC. We propose that this simple approach can provide, on the basis of a few parameters, rough estimate of the disturbance of the temperature caused by advecting fluid. Localized lateral BSR-based heat flow variations have been observed near thrust faults along many convergent plate boundaries around the world and are associated with strong localized fluid flow. We wish to further testing this approach using other seismic datasets to estimate first order of magnitude fluid migration patterns in other convergent boundaries.

  13. An investigation into thermal comfort and residential thermal environment in an intertropical sub-Saharan Africa region: Field study report during the Harmattan season in Cameroon

    International Nuclear Information System (INIS)

    Djongyang, Noel; Tchinda, Rene

    2010-01-01

    Investigations on thermal comfort have attracted authors for years throughout the world and the most important findings are now the basis of international thermal comfort standards. There is little information available concerning occupant comfort and residential thermal environment in the intertropical sub-Saharan Africa. Thus the purpose for this study is to conduct a field study on comfort and residential thermal environments in a typical intertropical climatic region. A field survey has been conducted during the Harmattan season in two cities from the two climatic regions of Cameroon concerned by that wind. Specific study objectives were to evaluate and characterize some thermal perceptions of occupants in their residence, compare observed and predicted percent of dissatisfied, and discern differences between the study area and other climate zones where similar studies have been performed. It was found that the thermoneutral temperatures in both climatic regions range from 24.69 deg. C to 27.32 deg. C and, in traditional living room, it differs from that of modern living room with approximately 1 deg. C.

  14. Real-time three-dimensional color doppler evaluation of the flow convergence zone for quantification of mitral regurgitation: Validation experimental animal study and initial clinical experience

    Science.gov (United States)

    Sitges, Marta; Jones, Michael; Shiota, Takahiro; Qin, Jian Xin; Tsujino, Hiroyuki; Bauer, Fabrice; Kim, Yong Jin; Agler, Deborah A.; Cardon, Lisa A.; Zetts, Arthur D.; hide

    2003-01-01

    BACKGROUND: Pitfalls of the flow convergence (FC) method, including 2-dimensional imaging of the 3-dimensional (3D) geometry of the FC surface, can lead to erroneous quantification of mitral regurgitation (MR). This limitation may be mitigated by the use of real-time 3D color Doppler echocardiography (CE). Our objective was to validate a real-time 3D navigation method for MR quantification. METHODS: In 12 sheep with surgically induced chronic MR, 37 different hemodynamic conditions were studied with real-time 3DCE. Using real-time 3D navigation, the radius of the largest hemispherical FC zone was located and measured. MR volume was quantified according to the FC method after observing the shape of FC in 3D space. Aortic and mitral electromagnetic flow probes and meters were balanced against each other to determine reference MR volume. As an initial clinical application study, 22 patients with chronic MR were also studied with this real-time 3DCE-FC method. Left ventricular (LV) outflow tract automated cardiac flow measurement (Toshiba Corp, Tokyo, Japan) and real-time 3D LV stroke volume were used to quantify the reference MR volume (MR volume = 3DLV stroke volume - automated cardiac flow measurement). RESULTS: In the sheep model, a good correlation and agreement was seen between MR volume by real-time 3DCE and electromagnetic (y = 0.77x + 1.48, r = 0.87, P time 3DCE-derived MR volume also showed a good correlation and agreement with the reference method (y = 0.89x - 0.38, r = 0.93, P time 3DCE can capture the entire FC image, permitting geometrical recognition of the FC zone geometry and reliable MR quantification.

  15. Modern Spatial Rainfall Rate is well Correlated with Coretop δ2Hdinosterol in the South Pacific Convergence Zone: A Tool for Quantitative Reconstructions of Rainfall Rate

    Science.gov (United States)

    Sear, D. A.; Maloney, A. E.; Nelson, D. B.; Sachs, J. P.; Hassall, J. D.; Langdon, P. G.; Prebble, M.; Richey, J. N.; Schabetsberger, R.; Sichrowsky, U.; Hope, G.

    2015-12-01

    The South Pacific Convergence Zone (SPCZ) is the Southern Hemisphere's most prominent precipitation feature extending southeastward 3000 km from Papua New Guinea to French Polynesia. Determining how the SPCZ responded to climate variations before the instrumental record requires the use of indirect indicators of rainfall. The link between the hydrogen isotopic composition of fluxes of water though the hydrologic cycle, lake water, and molecular fossil 2H/1H ratios make hydrogen isotopes a promising tool for improving our understanding of this important climate feature. An analysis of coretop sediment from freshwater lakes in the SPCZ region indicates that there is a strong spatial relationship between δ2Hdinosterol and mean annual precipitation rate. The objectives of this research are to use 2H/1H ratios of the biomarker dinosterol to develop an empirical relationship between δ2Hdinosterol and modern environmental rainfall rates so that we may quantitatively reconstruct several aspects of the SPCZ's hydrological system during the late Holocene. The analysis includes lake sediment coretops from the Solomon Islands, Wallis Island, Vanuatu, Tahiti, Samoa, New Caledonia, and the Cook Islands. These islands span range of average modern precipitation rates from 3 to 7 mm/day and the coretop sediment δ2Hdinosterol values range from -240‰ to -320‰. Applying this regional coretop calibration to dated sediment cores reveals that the mean annual position and/or intensity of the SPCZ has not been static during the past 2000 years.

  16. Modern Spatial Rainfall Rate is well Correlated with Coretop δ2Hdinosterol in the South Pacific Convergence Zone: a Tool for Quantitative Reconstructions

    Science.gov (United States)

    Maloney, A. E.; Nelson, D. B.; Sachs, J. P.; Hassall, J. D.; Sear, D. A.; Langdon, P. G.; Prebble, M.; Richey, J. N.; Schabetsberger, R.; Sichrowsky, U.; Hope, G.

    2016-02-01

    The South Pacific Convergence Zone (SPCZ) is the Southern Hemisphere's most prominent precipitation feature extending southeastward 3000 km from Papua New Guinea to French Polynesia. Determining how the SPCZ responded to climate variations before the instrumental record requires the use of indirect indicators of rainfall. The link between the hydrogen isotopic composition of water fluxes though the hydrologic cycle, lake water, and molecular fossil 2H/1H ratios make hydrogen isotopes a promising tool for improving our understanding of this important climate feature. An analysis of coretop sediment from freshwater lakes in the SPCZ region indicates that there is a strong spatial relationship between δ2Hdinosterol and mean annual precipitation rate. The objectives of this research are to use 2H/1H ratios of the biomarker dinosterol to develop an empirical relationship between δ2Hdinosterol and modern environmental rainfall rates so that we may quantitatively reconstruct several aspects of the SPCZ's hydrological system during the late Holocene. The analysis includes lake sediment coretops from the Solomon Islands, Wallis Island, Vanuatu, Tahiti, Samoa, New Caledonia, and the Cook Islands. These islands span range of average modern precipitation rates from 3 to 7 mm/day and the coretop sediment δ2Hdinosterol values range from -240‰ to -320‰. Applying this regional coretop calibration to dated sediment cores reveals that the mean annual position and/or intensity of the SPCZ has not been static during the past 2000 years.

  17. Network Convergence

    Indian Academy of Sciences (India)

    First page Back Continue Last page Overview Graphics. Network Convergence. User is interested in application and content - not technical means of distribution. Boundaries between distribution channels fade out. Network convergence leads to seamless application and content solutions.

  18. Determination of stable and radioactive isotopes in rain water for the equatorial and Sahel zones

    International Nuclear Information System (INIS)

    Baudet, J.; Lesne, H.

    1975-01-01

    The extension of desert zones to detriment of Sahel zones lead to look for the circuit followed by water vapor between its principal source, i.e. the Guinea Gulf, and the place where it is changed in precipitation. Samples of rainwater have been collected in Abidjan, Ouagadougou, and Niamey when the Intertropical Front was beginning its moving down towards the South, i.e. at the end of the rainy season for the Sahel zone, and at the beginning of the small rainy season for the equatorial zone. The analysis of these tritium, deuterium and oxygen-18 contents show that: the rains collected in Abidjan comes mainly from Ocean; the rains collected in Ouagadougou and Niamey have followed a long journey above the continent, as shown by the tritium content. The water evaporated in the Guinea Gulf is condensed in the convergence zone above Cameroon, and mixed with re-evaporated continental water. The content of one of the Ouagadougou sample shows that the rain issued from a local cumulonimbus has drawn a part of its water from the stratosphere [fr

  19. South Pacific Convergence Zone Changes during the Late Holocene Identified from Hydrogen Isotope Ratios of Terrestrial and Aquatic Biomarkers from Freshwater Lake Sediments in Vanuatu

    Science.gov (United States)

    Maloney, A. E.; Ladd, N.; Nelson, D. B.; Sachs, J. P.; Dubois, N.

    2017-12-01

    The South Pacific Convergence Zone (SPCZ) is one of Earth's major precipitation features. Mean annual rainfall rates are as high as 10 mm/day in the Solomon Islands in the northwest portion of the SPCZ, and decline to 4 mm/day in portions of French Polynesia the southeastern reach of the SPCZ. Coral records suggest that the mean annual position and precipitation intensity associated with the SPCZ have most likely expanded and contracted on decadal to centennial timescales, but existing data is limited, making it difficult to constrain and characterize these changes. Thion Island (15.03 °S, 167.09 °E) is located off the east coast of Espírito Santo in Vanuatu, at an intermediate position in the modern SPCZ. As such, it should be sensitive to major contractions and expansions of the SPCZ, with wetter conditions when the SPCZ expands southeast, and drier conditions when it contracts to the northwest. In order to determine changes in precipitation over the past millennium on Thion Island, we collected sediment cores from two adjacent freshwater lakes on the island, White Lake and Red Lake, and measured compound specific hydrogen isotope ratios (2H/1H) of lipid biomarkers from terrestrial plants (long-chain n-alkanes and n­-alkanoic acids), aquatic plants (mid-chain n­-alkanes and n-alkanoic acids), and microalgae (dinosterol and botryococcenes). For all measured biomarkers, 2H/1H ratios were higher during the Little Ice Age (LIA, late 14th century to early 19th century) relative to the preceding Medieval Climate Anomaly (MCA) and to the 20th century, suggesting drier conditions at this location during the LIA. The magnitude of decrease in 2H/1H ratios was twice as large for microalgal dinosterol ( 40 ‰ decrease) as for leaf waxes associated with higher plants ( 20 ‰ decrease). The leaf wax data likely reflects changes in precipitation isotopes due to the amount effect, while the microalgal values should change with lake water 2H/1H, which is sensitive to both

  20. Evidence of cretaceous to recent West African intertropical vegetation from continental sediment spore-pollen analysis

    Science.gov (United States)

    Salard-Cheboldaeff, M.; Dejax, J.

    The succession of spore-pollen assemblages during the Cretaceous and Tertiary, as defined in each of the basin from Senegal to Angola, gives the possibility to consider the intertropical African flora evolution for the past 120 M.a. During the Early Cretaceous, xeric-adapted gymnosperms and various ferns were predominant the flora which nevertheless comprises previously unknown early angiosperm pollen. During the Middle Cretaceous, gymnospers were gradually replaced by angiosperms; these became more and more abundant, along with the diversification of new genera and species. During the Paleocene, the radiation of the monocotyledons (mainly that of the palm-trees) as well as a greater diversification among the dicotyledons and ferms are noteworthy. Since gymnosperms had almost disappeared by the Eocene, the diversification of the dicotyledons went on until the neogene, when all extinct pollen types are already present. These important modifications of the vegetation reflect evolutionary trends as well as climatic changes during the Cretaceous: the climate, firstly hot, dry and perhaps arid, did probably induced salt deposition, and later became gradually more humid under oceanic influences which arose in connection with the Gondwana break-up.

  1. A database for the monitoring of thermal anomalies over the Amazon forest and adjacent intertropical oceans.

    Science.gov (United States)

    Jiménez-Muñoz, Juan C; Mattar, Cristian; Sobrino, José A; Malhi, Yadvinder

    2015-01-01

    Advances in information technologies and accessibility to climate and satellite data in recent years have favored the development of web-based tools with user-friendly interfaces in order to facilitate the dissemination of geo/biophysical products. These products are useful for the analysis of the impact of global warming over different biomes. In particular, the study of the Amazon forest responses to drought have recently received attention by the scientific community due to the occurrence of two extreme droughts and sustained warming over the last decade. Thermal Amazoni@ is a web-based platform for the visualization and download of surface thermal anomalies products over the Amazon forest and adjacent intertropical oceans using Google Earth as a baseline graphical interface (http://ipl.uv.es/thamazon/web). This platform is currently operational at the servers of the University of Valencia (Spain), and it includes both satellite (MODIS) and climatic (ERA-Interim) datasets. Thermal Amazoni@ is composed of the viewer system and the web and ftp sites with ancillary information and access to product download.

  2. Convergence Insufficiency

    Science.gov (United States)

    ... is also found to be weak. If both accommodation and convergence are weak, reading glasses, sometimes with prism added, may be a great option for these patients. It is very difficult to improve accommodation with exercises. Updated 7/2017 Eye Terms & Conditions ...

  3. Chronology and ancient feeding ecology of two upper Pleistocene megamammals from the Brazilian Intertropical Region

    Science.gov (United States)

    de Melo França, Lucas; Trindade Dantas, Mário André; Bocchiglieri, Adriana; Cherckinsky, Alexander; de Souza Ribeiro, Adauto; Bocherens, Hervé

    2014-09-01

    In Brazilian Intertropical Region (BIR) fossil remains of the giant ground sloth Eremotherium laurillardi (Lund, 1842) and of the proboscidean Notiomastodon platensis (Ameghino, 1888) are the most abundant among megaherbivores. However, the paleoecology of both species needs to be better understood to enlighten why these species disappear in the end of the Pleistocene, an issue that is still debated. During the last decades, the carbon and oxygen stable isotopes have been increasingly being used to obtain paleoecological information about extinct animals, although this information is in most cases dissociated from chronological data. Thus, the main objective of this study is to contribute to the knowledge about feeding ecology and chronology of E. laurillardi and N. platensis within BIR. For each fossil sample we performed stable isotopes analyses (δ13C/δ18O) and radiocarbon dating (14C with AMS). The results showed that N. platensis occurred between 12,125 and 19,594 cal yr BP and exhibited a grazer diet (δ13C = -1.1‰-1.3‰), while E. laurillardi lived between 11,084 and 27,690 cal yr BP, with a mixed feeder diet (C3/C4 plants; values ratio δ13C = -7.7‰ to -3.3‰). The δ18O values of N. platensis ranged between 2.20‰ and 3.60‰, while the values of E. laurillardi ranged between -3.10‰ and -1.10‰. Neither species did exhibit differences in its diet through time, which suggests that the vegetational composition of this locality did not vary in the late Pleistocene. Both species were living in an open environment, rich in herbaceous plants (C4 plants) and with tree and shrub with disjoint distribution, maybe similar to some parts of recent Caatinga, where they have partitioned the spatial and feeding niches.

  4. Do convergent developmental mechanisms underlie convergent phenotypes?

    Science.gov (United States)

    Wray, Gregory A.

    2002-01-01

    Convergence is a pervasive evolutionary process, affecting many aspects of phenotype and even genotype. Relatively little is known about convergence in developmental processes, however, nor about the degree to which convergence in development underlies convergence in anatomy. A switch in the ecology of sea urchins from feeding to nonfeeding larvae illustrates how convergence in development can be associated with convergence in anatomy. Comparisons to more distantly related taxa, however, suggest that this association may be limited to relatively close phylogenetic comparisons. Similarities in gene expression during development provide another window into the association between convergence in developmental processes and convergence in anatomy. Several well-studied transcription factors exhibit likely cases of convergent gene expression in distantly related animal phyla. Convergence in regulatory gene expression domains is probably more common than generally acknowledged, and can arise for several different reasons. Copyright 2002 S. Karger AG, Basel.

  5. Convergence in Multispecies Interactions

    OpenAIRE

    Bittleston, Leonora Sophia; Pierce, Naomi E.; Ellison, Aaron M.; Pringle, Anne

    2016-01-01

    The concepts of convergent evolution and community convergence highlight how selective pressures can shape unrelated organisms or communities in similar ways. We propose a related concept, convergent interactions, to describe the independent evolution of multispecies interactions with similar physiological or ecological functions. A focus on convergent interactions clarifies how natural selection repeatedly favors particular kinds of associations among species. Characterizing convergent inter...

  6. Imaging the structure of the Northern Lesser Antilles (Guadeloupe - Virgin Island) to assess the tectonic and thermo-mechanical behavior of an arcuate subduction zone that undergoes increasing convergence obliquity

    Science.gov (United States)

    Laurencin, M.; Marcaillou, B.; Klingelhoefer, F.; Jean-Frederic, L.; Graindorge, D.; Bouquerel, H.; Conin, M.; Crozon, J.; De Min, L.; De Voogd, B.; Evain, M.; Heuret, A.; Laigle, M.; Lallemand, S.; Lucazeau, F.; Pichot, T.; Prunier, C.; Rolandone, F.; Rousset, D.; Vitard, C.

    2015-12-01

    Paradoxically, the Northern Lesser Antilles is the less-investigated and the most tectonically and seismically complex segment of the Lesser Antilles subduction zone: - The convergence obliquity between the North American and Caribbean plates increases northward from Guadeloupe to Virgin Islands raising questions about the fore-arc tectonic partitioning. - The margin has undergone the subduction of the rough sediment-starved Atlantic Ocean floor spiked with ridges as well as banks docking, but the resulting tectonic deformation remains hypothetical in the absence of a complete bathymetry and of any seismic line. - Recent geodetic data and low historical seismic activity suggest a low interplate coupling between Saint-Martin and Anegada, but the sparse onshore seismometers located far from source zone cast doubt on this seismic gap. To shed new light on these questions, the ANTITHESIS project, 5 Marine Geophysical legs totaling 72 days, aims at recording a complete bathymetric map, deep and shallow seismic reflexion lines, wide-angle seismic data, heat-flow measurements and the seismic activity with a web of sea-bottom seismometers. Our preliminary results suggest that: - A frontal sliver of accretionary prism is stretched and expulsed northward by 50km along the left-lateral Bunce fault that limits the prism from the margin basement as far southward as 18.5°N. So far, this structure is the only interpreted sign of tectonic partitioning in the fore-arc. - The Anegada Passage extends eastward to the accretionary prism through strike-slip faults and pull-apart basins that possibly form a lef-lateral poorly-active system inherited from a past tectonic phase, consistently with geodetic and seismologic data. - The anomalously cold interplate contact, consistent with a low interseismic coupling, is possibly due to fluid circulation within the shallow crustal aquifer or a depressed thermal structure of the oceanic crust related to the slow-spreading at the medio

  7. The EU's Convergence Dilemma

    Directory of Open Access Journals (Sweden)

    Notermans Ton

    2015-02-01

    Full Text Available As economic stagnation continues to mark the EU in the fifth year of the euro zone crisis, political support for integration is waning. The European Parliament elections of 2014 returned a hitherto unparalleled number of Eurosceptic MEPs, with EU-critical parties becoming the largest ones in several Member States. Much of this Euroscepticism is driven by economic polarisation between core and peripheral countries. While an increasing number of voters in the northwestern creditor countries resent having to foot the bill for what they consider economic mismanagement in the periphery, voters in peripheral countries increasingly rebel against what they deem to be an economically catastrophic Diktat from Germany and its allies. Continued political support for European integration will hinge on successful income convergence in the EU but the current dilemma is that such policies might not be politically feasible. Periods of rapid convergence would seem to suggest that success depends on two main policy strategies. First, a monetary policy that promotes credit for productive purposes, leaves inflation control to other instruments, and employs selective credit rationing to prevent asset booms. Second, a vertical industrial policy prioritising selected industrial sectors. The first policy conflicts with the present framework of euro zone monetary policy, but that framework was only installed in the first place because many peripheral countries were desperately in search of an external constraint on domestic distributional conflict. Industrial policies, in turn, require a sufficient degree of state autonomy from business elites in order to be effective, but it is highly questionable whether most states in the EU possess such autonomy. Though there are, as yet hesitant, signs of a reorientation of both monetary and cohesion policy in the EU, the question of the institutional and political preconditions for their successful implementation has been largely

  8. A Fiji multi-coral δ18O composite approach to obtaining a more accurate reconstruction of the last two-centuries of the ocean-climate variability in the South Pacific Convergence Zone region

    Science.gov (United States)

    Dassié, Emilie P.; Linsley, Braddock K.; Corrège, Thierry; Wu, Henry C.; Lemley, Gavin M.; Howe, Steve; Cabioch, Guy

    2014-12-01

    The limited availability of oceanographic data in the tropical Pacific Ocean prior to the satellite era makes coral-based climate reconstructions a key tool for extending the instrumental record back in time, thereby providing a much needed test for climate models and projections. We have generated a unique regional network consisting of five Porites coral δ18O time series from different locations in the Fijian archipelago. Our results indicate that using a minimum of three Porites coral δ18O records from Fiji is statistically sufficient to obtain a reliable signal for climate reconstruction, and that application of an approach used in tree ring studies is a suitable tool to determine this number. The coral δ18O composite indicates that while sea surface temperature (SST) variability is the primary driver of seasonal δ18O variability in these Fiji corals, annual average coral δ18O is more closely correlated to sea surface salinity (SSS) as previously reported. Our results highlight the importance of water mass advection in controlling Fiji coral δ18O and salinity variability at interannual and decadal time scales despite being located in the heavy rainfall region of the South Pacific Convergence Zone (SPCZ). The Fiji δ18O composite presents a secular freshening and warming trend since the 1850s coupled with changes in both interannual (IA) and decadal/interdecadal (D/I) variance. The changes in IA and D/I variance suggest a re-organization of climatic variability in the SPCZ region beginning in the late 1800s to period of a more dominant interannual variability, which could correspond to a southeast expansion of the SPCZ.

  9. Variability in warm-season atmospheric circulation and precipitation patterns over subtropical South America: relationships between the South Atlantic convergence zone and large-scale organized convection over the La Plata basin

    Science.gov (United States)

    Mattingly, Kyle S.; Mote, Thomas L.

    2017-01-01

    Warm-season precipitation variability over subtropical South America is characterized by an inverse relationship between the South Atlantic convergence zone (SACZ) and precipitation over the central and western La Plata basin of southeastern South America. This study extends the analysis of this "South American Seesaw" precipitation dipole to relationships between the SACZ and large, long-lived mesoscale convective systems (LLCSs) over the La Plata basin. By classifying SACZ events into distinct continental and oceanic categories and building a logistic regression model that relates LLCS activity across the region to continental and oceanic SACZ precipitation, a detailed account of spatial variability in the out-of-phase coupling between the SACZ and large-scale organized convection over the La Plata basin is provided. Enhanced precipitation in the continental SACZ is found to result in increased LLCS activity over northern, northeastern, and western sections of the La Plata basin, in association with poleward atmospheric moisture flux from the Amazon basin toward these regions, and a decrease in the probability of LLCS occurrence over the southeastern La Plata basin. Increased oceanic SACZ precipitation, however, was strongly related to reduced atmospheric moisture and decreased probability of LLCS occurrence over nearly the entire La Plata basin. These results suggest that continental SACZ activity and large-scale organized convection over the northern and eastern sections of the La Plata basin are closely tied to atmospheric moisture transport from the Amazon basin, while the warm coastal Brazil Current may also play an important role as an evaporative moisture source for LLCSs over the central and western La Plata basin.

  10. Alternative glacial-interglacial refugia demographic hypotheses tested on Cephalocereus columna-trajani (Cactaceae) in the intertropical Mexican drylands.

    Science.gov (United States)

    Cornejo-Romero, Amelia; Vargas-Mendoza, Carlos Fabián; Aguilar-Martínez, Gustavo F; Medina-Sánchez, Javier; Rendón-Aguilar, Beatriz; Valverde, Pedro Luis; Zavala-Hurtado, Jose Alejandro; Serrato, Alejandra; Rivas-Arancibia, Sombra; Pérez-Hernández, Marco Aurelio; López-Ortega, Gerardo; Jiménez-Sierra, Cecilia

    2017-01-01

    Historic demography changes of plant species adapted to New World arid environments could be consistent with either the Glacial Refugium Hypothesis (GRH), which posits that populations contracted to refuges during the cold-dry glacial and expanded in warm-humid interglacial periods, or with the Interglacial Refugium Hypothesis (IRH), which suggests that populations contracted during interglacials and expanded in glacial times. These contrasting hypotheses are developed in the present study for the giant columnar cactus Cephalocereus columna-trajani in the intertropical Mexican drylands where the effects of Late Quaternary climatic changes on phylogeography of cacti remain largely unknown. In order to determine if the historic demography and phylogeographic structure of the species are consistent with either hypothesis, sequences of the chloroplast regions psbA-trnH and trnT-trnL from 110 individuals from 10 populations comprising the full distribution range of this species were analysed. Standard estimators of genetic diversity and structure were calculated. The historic demography was analysed using a Bayesian approach and the palaeodistribution was derived from ecological niche modelling to determine if, in the arid environments of south-central Mexico, glacial-interglacial cycles drove the genetic divergence and diversification of this species. Results reveal low but statistically significant population differentiation (FST = 0.124, P < 0.001), although very clear geographic clusters are not formed. Genetic diversity, haplotype network and Approximate Bayesian Computation (ABC) demographic analyses suggest a population expansion estimated to have taken place in the Last Interglacial (123.04 kya, 95% CI 115.3-130.03). The species palaeodistribution is consistent with the ABC analyses and indicates that the potential area of palaedistribution and climatic suitability were larger during the Last Interglacial and Holocene than in the Last Glacial Maximum. Overall

  11. Convergence in Multispecies Interactions.

    Science.gov (United States)

    Bittleston, Leonora S; Pierce, Naomi E; Ellison, Aaron M; Pringle, Anne

    2016-04-01

    The concepts of convergent evolution and community convergence highlight how selective pressures can shape unrelated organisms or communities in similar ways. We propose a related concept, convergent interactions, to describe the independent evolution of multispecies interactions with similar physiological or ecological functions. A focus on convergent interactions clarifies how natural selection repeatedly favors particular kinds of associations among species. Characterizing convergent interactions in a comparative context is likely to facilitate prediction of the ecological roles of organisms (including microbes) in multispecies interactions and selective pressures acting in poorly understood or newly discovered multispecies systems. We illustrate the concept of convergent interactions with examples: vertebrates and their gut bacteria; ectomycorrhizae; insect-fungal-bacterial interactions; pitcher-plant food webs; and ants and ant-plants. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Converged Registries Solution (CRS)

    Data.gov (United States)

    Department of Veterans Affairs — The Converged Registries platform is a hardware and software architecture designed to host individual patient registries and eliminate duplicative development effort...

  13. Development of the Scale for "Convergence Thinking" in Engineering

    Science.gov (United States)

    Park, Sungmi

    2016-01-01

    Purpose: The purpose of this paper is to define the concept of "convergence thinking" as a trading zone for knowledge fusion in the engineering field, and develops its measuring scale. Design/ Methodology/Approach: Based on results from literature review, this study clarifies a theoretical ground for "convergence thinking."…

  14. Geochemistry of organic-rich river waters in Amazonia: Insights on weathering processes of intertropical cratonic terrain

    International Nuclear Information System (INIS)

    Horbe, Adriana Maria Coimbra; Lages, Anderson da Silva; Moquet, Jean-Sébastien; Santos, Roberto Ventura; Seyler, Patrick

    2016-01-01

    In this study, eight organic-rich rivers that flow through the Brazilian craton in the southwestern Amazon rainforest are investigated. This investigation is the first of its type in this area and focuses on the effects of lithology, long-term weathering, thick soils, forest cover and hydrological period on the dissolved load compositions in rivers draining cratonic terrain. The major dissolved ion concentrations, alkalinity (TAlk), SiO 2 , trace element concentrations, and Sr isotope contents in the water were determined between April 2009 and January 2010. In addition, the isotopic values of oxygen and hydrogen were determined between 2011 and 2013. Overall, the river water is highly dilute and dominated by the major dissolved elements TAlk, SiO 2 and K + and the major dissolved trace elements Al, Fe, Ba, Mn, P, Zn and Sr, which exhibit large temporal and spatial variability and are closely correlated with the silicatic bedrock and hydrology. Additionally, rainwater and recycled water vapor and the size of the basin contribute to the geochemistry of the waters. The total weathering flux estimated from our results is 2–4 t km −2 .yr −1 , which is one of the lowest fluxes in the world. The CO 2 consumption rate is approximately 21–61 10 3  mol km −2  yr −1 , which is higher than expected given the stability of the felsic to basic igneous and metamorphic to siliciclastic basement rocks and the thick tropical soil cover. Thus, weathering of the cratonic terrain under intertropical humid conditions is still an important consumer of CO 2 . - Highlights: • Were studied rivers flowing the Brazilian craton covered by lateritic soils. • The river waters are highly diluted and dominated by TAlk, SiO 2 and K + . • There is spatial and temporal variability in the chemical composition. • The rain amount and recycled water vapor affect the O and D isotopes. • Geology, weathering, discharge and seasonality highlight a singular composition.

  15. Convergence of mayer expansions

    International Nuclear Information System (INIS)

    Brydges, D.C.

    1986-01-01

    The tree graph bound of Battle and Federbush is extended and used to provide a simple criterion for the convergence of (iterated) Mayer expansions. As an application estimates on the radius of convergence of the Mayer expansion for the two-dimensional Yukawa gas (nonstable interaction) are obtained

  16. Almost convergence of triple sequences

    OpenAIRE

    Ayhan Esi; M.Necdet Catalbas

    2013-01-01

    In this paper we introduce and study the concepts of almost convergence and almost Cauchy for triple sequences. Weshow that the set of almost convergent triple sequences of 0's and 1's is of the first category and also almost everytriple sequence of 0's and 1's is not almost convergent.Keywords: almost convergence, P-convergent, triple sequence.

  17. Convergence of Nelson diffusions

    International Nuclear Information System (INIS)

    Dell'Antonio, G.; Posilicano, A.

    1991-01-01

    Let ψ t , ψ t n , n≥1, be solutions of Schroedinger equations with potentials form-bounded by -1/2 Δ and initial data in H 1 (R d ). Let P, P n , n≥1, be the probability measures on the path space Ω=C(R + , R d ) given by the corresponding Nelson diffusions. We show that if {ψ t n } n≥1 converges to ψ t in H 2 (R d ), uniformly in t over compact intervals, then {P n } n≥1 converges to P in total variation. Moreover, if the potentials are in the Kato class K d , we show that the above result follows from H 1 -convergence of initial data, and K d -convergence of potentials. (orig.)

  18. Fixed mobile convergence handbook

    CERN Document Server

    Ahson, Syed A

    2010-01-01

    From basic concepts to future directions, this handbook provides technical information on all aspects of fixed-mobile convergence (FMC). The book examines such topics as integrated management architecture, business trends and strategic implications for service providers, personal area networks, mobile controlled handover methods, SIP-based session mobility, and supervisory and notification aggregator service. Case studies are used to illustrate technical and systematic implementation of unified and rationalized internet access by fixed-mobile network convergence. The text examines the technolo

  19. Deforestation and leaching of nitrogen as nitrates into underground water in intertropical zones: The example of Cote d'Ivoire (the Ivory Coast)

    International Nuclear Information System (INIS)

    Faillat, J.P.; Rambaud, A.

    1991-01-01

    High nitrate contents (up to 200 mgl) has been observed in wells drilled into fractured aquifers lying beneath layers of weathered and decayed rock in the humid tropics where annual rainfall is over 1,000 mm and where there is no notable pollution. The source of the nitrates is linked mainly with localized deforestation by man

  20. IT-BT convergence technology

    International Nuclear Information System (INIS)

    2012-12-01

    This book explains IT-BT convergence technology as the future technology, which includes a prolog, easy IT-BT convergence technology that has infinite potentials for new value, policy of IT-BT convergence technology showing the potential of smart Korea, IT-BT convergence opening happy future, for the new future of IT powerful nation Korea with IT-BT convergence technology and an epilogue. This book reveals the conception, policy, performance and future of IT-BT convergence technology.

  1. Convergent plate margin dynamics : New perspectives from structural geology, geophysics and geodynamic modelling

    NARCIS (Netherlands)

    Schellart, W. P.; Rawlinson, N.

    2010-01-01

    Convergent plate margins occur when two adjoining tectonic plates come together to form either a subduction zone, where at least one of the converging plates is oceanic and plunges beneath the other into the mantle, or a collision zone, where two continents or a continent and a magmatic arc collide.

  2. Secas Island Stable Isotope Data (delta 18O) for 1707 to 1984

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Secas Island Coral d18O, used to reconstruct seasonal and interannual variability in the Intertropical Convergence Zone. Site Location: Secas Island, Gulf of...

  3. Convergence from divergence

    Science.gov (United States)

    Costin, Ovidiu; Dunne, Gerald V.

    2018-01-01

    We show how to convert divergent series, which typically occur in many applications in physics, into rapidly convergent inverse factorial series. This can be interpreted physically as a novel resummation of perturbative series. Being convergent, these new series allow rigorous extrapolation from an asymptotic region with a large parameter, to the opposite region where the parameter is small. We illustrate the method with various physical examples, and discuss how these convergent series relate to standard methods such as Borel summation, and also how they incorporate the physical Stokes phenomenon. We comment on the relation of these results to Dyson’s physical argument for the divergence of perturbation theory. This approach also leads naturally to a wide class of relations between bosonic and fermionic partition functions, and Klein-Gordon and Dirac determinants.

  4. On the Fuzzy Convergence

    Directory of Open Access Journals (Sweden)

    Abdul Hameed Q. A. Al-Tai

    2011-01-01

    Full Text Available The aim of this paper is to introduce and study the fuzzy neighborhood, the limit fuzzy number, the convergent fuzzy sequence, the bounded fuzzy sequence, and the Cauchy fuzzy sequence on the base which is adopted by Abdul Hameed (every real number r is replaced by a fuzzy number r¯ (either triangular fuzzy number or singleton fuzzy set (fuzzy point. And then, we will consider that some results respect effect of the upper sequence on the convergent fuzzy sequence, the bounded fuzzy sequence, and the Cauchy fuzzy sequence.

  5. Convergence of Networks

    DEFF Research Database (Denmark)

    Prasad, Ramjee; Ruggieri, Marina

    2008-01-01

    The paper focuses on the revolutionary changes that could characterise the future of networks. Those changes involve many aspects in the conceivement and exploitation of networks: architecture, services, technologies and modeling. The convergence of wired and wireless technologies along...... with the integration of system componennts and the convergence of services (e.g. communications and navigation) are only some of the elements that shape the perpsected mosaic. Authors delineate this vision, highlighting the presence of the space and stratospheric components and the related services as building block...

  6. Convergent Filter Bases

    Directory of Open Access Journals (Sweden)

    Coghetto Roland

    2015-09-01

    Full Text Available We are inspired by the work of Henri Cartan [16], Bourbaki [10] (TG. I Filtres and Claude Wagschal [34]. We define the base of filter, image filter, convergent filter bases, limit filter and the filter base of tails (fr: filtre des sections.

  7. Converging or Diverging Lens?

    Science.gov (United States)

    Branca, Mario

    2013-01-01

    Why does a lens magnify? Why does it shrink objects? Why does this happen? The activities that we propose here are useful in helping us to understand how lenses work, and they show that the same lens can have different magnification capabilities. A converging lens can also act as a diverging lens. (Contains 4 figures.)

  8. Language Convergence Infrastructure

    NARCIS (Netherlands)

    V. Zaytsev (Vadim); J.M. Fernandes; R. Lämmel (Ralf); J.M.W. Visser (Joost); J. Saraiva

    2011-01-01

    htmlabstractThe process of grammar convergence involves grammar extraction and transformation for structural equivalence and contains a range of technical challenges. These need to be addressed in order for the method to deliver useful results. The paper describes a DSL and the infrastructure behind

  9. The Convergence Years

    Science.gov (United States)

    Kolodzy, Janet; Grant, August E.; DeMars, Tony R.; Wilkinson, Jeffrey S.

    2014-01-01

    The emergence of the Internet, social media, and digital technologies in the twenty-first century accelerated an evolution in journalism and communication that fit under the broad term of convergence. That evolution changed the relationship between news producers and consumers. It broke down the geographical boundaries in defining our communities,…

  10. Summable series and convergence factors

    CERN Document Server

    Moore, Charles N

    1938-01-01

    Fairly early in the development of the theory of summability of divergent series, the concept of convergence factors was recognized as of fundamental importance in the subject. One of the pioneers in this field was C. N. Moore, the author of the book under review.... Moore classifies convergence factors into two types. In type I he places the factors which have only the property that they preserve convergence for a convergent series or produce convergence for a summable series. In type II he places the factors which not only maintain or produce convergence but have the additional property that

  11. The Convergent Learning Space

    DEFF Research Database (Denmark)

    Kjeldsen, Lars Peter; Kjærgaard, Hanne Wacher

    networks are still more prominently expected by students. Against this backdrop, an action research project has worked with the definition and testing of the hypothesized constituents of the Convergent Learning Space and how it challenges our traditional conceptions of learning spaces. The article...... describes this pilot study involving teachers in conscious, documented reflection on methods, approaches, and procedures conducive to learning processes in this new learning space. As a perspective, the article briefly outlines an intervention study aimed at investigating how students benefit from......The concept of the Convergent Learning Space has been hypothesized and explored in an ongoing action research project carried out at undergraduate level in select bachelor programs at a Danish University College, where classrooms are technology rich and students bring their own devices. The changes...

  12. The Convergent Learning Space:

    DEFF Research Database (Denmark)

    Kjærgaard, Hanne Wacher; Kjeldsen, Lars Peter; Asmussen, Jørgen Bering

    is described as well as the theoretical construct and hypotheses surrounding the emergence of the concept in technology-rich classrooms, where students bring their own devices and involve their personal learning spaces and networks. The need for new ways of approaching concepts like choice, learning resources......This paper describes the concept of “The Convergent Learning Space” as it is being explored in an ongoing action research project carried out at undergraduate level in select bachelor programs at a Danish University College. The background nature, design, and beginning of this work in progress......, trajectories of participation etc. calls for new action and new pedagogies by teachers in order to secure alignment between students’ worlds and expectations and aims and plans of the teacher. Action research methods are being used to define and test the constituents and variables of the convergent learning...

  13. Regulating ICT convergence

    OpenAIRE

    Simpson, Seamus

    2015-01-01

    The Broadcasting, Information Technology and Telecommunications sectors have in recent years been the subject of notable transformation, one important feature of which is their coming closer together in a number of ways - it is now commonplace to speak of a new hybrid sector, Information and Communications Technologies (ICTs). This convergence is of considerable interest to policy-makers in industry and government at the national and international level, as well as the academic community and,...

  14. Convergence semigroup categories

    Directory of Open Access Journals (Sweden)

    Gary Richardson

    2013-09-01

    Full Text Available Properties of the category consisting of all objects of the form (X, S, λ are investigated, where X is a convergence space, S is a commutative semigroup, and λ: X × S → X is a continuous action. A “generalized quotient” of each object is defined without making the usual assumption that for each fixed g ∈ S, λ(., g : X  → X is an injection.

  15. Multiplier convergent series and uniform convergence of mapping ...

    Indian Academy of Sciences (India)

    MS received 14 April 2011; revised 17 November 2012. Abstract. In this paper, we introduce the frame property of complex sequence sets and study the uniform convergence of nonlinear mapping series in β-dual of spaces consisting of multiplier convergent series. Keywords. Multiplier convergent series; mapping series. 1.

  16. Convergence semigroup actions: generalized quotients

    Directory of Open Access Journals (Sweden)

    H. Boustique

    2009-10-01

    Full Text Available Continuous actions of a convergence semigroup are investigated in the category of convergence spaces. Invariance properties of actions as well as properties of a generalized quotient space are presented

  17. IT Convergence and Security 2012

    CERN Document Server

    Chung, Kyung-Yong

    2013-01-01

    The proceedings approaches the subject matter with problems in technical convergence and convergences of security technology. This approach is new because we look at new issues that arise from techniques converging. The general scope of the proceedings content is convergence security and the latest information technology. The intended readership are societies, enterprises, and research institutes, and intended content level is mid- to highly educated personals. The most important features and benefits of the proceedings are the introduction of the most recent information technology and its related ideas, applications and problems related to technology convergence, and its case studies and finally an introduction of converging existing security techniques through convergence security. Overall, through the proceedings, authors will be able to understand the most state of the art information strategies and technologies of convergence security.

  18. Cultura da Convergência

    Directory of Open Access Journals (Sweden)

    Rogério Christofoletti

    2008-12-01

    Full Text Available Three ideas would suffice for the reading of “Cultura da Convergência” (Culture of Convergence by Henry Jenkins to be of interest to journalists and researchers in the area: media convergence as a cultural process; the strengthening of an emotional economy which guides consumers of symbolic goods and media creators; the expansion of trans-media narrative forms.

  19. Cultura da Convergência

    Directory of Open Access Journals (Sweden)

    Rogério Christofoletti

    2011-02-01

    Full Text Available Three ideas would suffice for the reading of “Cultura da Convergência” (Culture of Convergence by Henry Jenkins to be of interest to journalists and researchers in the area: media convergence as a cultural process; the strengthening of an emotional economy which guides consumers of symbolic goods and media creators; the expansion of trans-media narrative forms.

  20. Influence of the balance of the intertropical front on seasonal variations of the isotopic composition in rainfall at Kisiba Masoko (Rungwe Volcanic Province, SW, Tanzania).

    Science.gov (United States)

    Nivet, Fantine; Bergonzini, Laurent; Mathé, Pierre-Etienne; Noret, Aurélie; Monvoisin, Gaël; Majule, Amos; Williamson, David

    2018-08-01

    Tropical rainfall isotopic composition results from complex processes. The climatological and environmental variability in East Africa increases this complexity. Long rainfall isotope datasets are needed to fill the lack of observations in this region. At Kisiba Masoko, Tanzania, rainfall and rain isotopic composition have been monitored during 6 years. Mean year profiles allow to analyse the seasonal variations. The mean annual rainfall is 2099 mm with a rain-weighted mean composition of -3.2 ‰ for δ 18 O and -11.7 ‰ for δ 2 H. The results are consistent with available data although they present their own specificity. Thus, if the local meteoric water line is δ 2 H = 8.6 δ 18 O + 14.8, two seasonal lines are observed. The seasonality of the isotopic composition in rain and deuterium excess has been compared with precipitating air masses backtracking trajectories to characterize a simple scheme of vapour histories. The three major oceanic sources have two moisture signatures with their own trajectory histories: one originated from the tropical Indian Ocean at the beginning of the rainy season and one from the Austral Ocean at its end. The presented isotopic seasonality depends on the balance of the intertropical front and provides a useful dataset to improve the knowledge about local processes.

  1. Local Convergence and Radius of Convergence for Modified Newton Method

    Directory of Open Access Journals (Sweden)

    Măruşter Ştefan

    2017-12-01

    Full Text Available We investigate the local convergence of modified Newton method, i.e., the classical Newton method in which the derivative is periodically re-evaluated. Based on the convergence properties of Picard iteration for demicontractive mappings, we give an algorithm to estimate the local radius of convergence for considered method. Numerical experiments show that the proposed algorithm gives estimated radii which are very close to or even equal with the best ones.

  2. Medialogy - convergence and transdisciplinarity

    DEFF Research Database (Denmark)

    Nordahl, Rolf

    2007-01-01

    Art and design have many qualities which intuitively by society are appreciated. But on daily basis they are also assessed and evaluated. Some communities also share common understandings that norms, standards, conventions evolve, both from artistic desire as well as from more physical needs...... for changes in society, developments in taste etc.  However, it certainly seems fair to say, that available technology makes a great difference to the development of any art form or practice. With the up rise of new educations such as Medialogy, new aspects of convergence and different forms...... of interdisciplinarity and transdisciplinarity is a pre-requisite for both researchers and students. In this talk we will demonstrate our approach through concrete examples of student productions and projects. We will also display the pedagogical method (problem based learning), that enables students to bridge gaps...

  3. DOES THE MAASTRICHT CONVERGENCE CRITERIA WORK?

    Directory of Open Access Journals (Sweden)

    Karsai Zoltán-Krisztián

    2012-12-01

    Full Text Available During its 13 year history, the euro area experienced the most severe economic downturn in the late 2000s as a result of the 2007 financial-economic crisis stemming from the US banking sector. The crisis in the monetary union, besides posting a significant economic and social cost, revealed several weaknesses not just of the currency block as a whole, but also of its constituting members, which were masked by the prosperous economic environment characteristic for the 2000s. These conditions have put to the test the solidarity among the euro zone members, or in other words the existence of the currency block. One important problem of the currency block is the lack of harmony between the fiscal and economic policies of the member states, creating several and occasionally very divergent parts of the currency block. The aim of this research is to enhance the Maastricht convergence criteria’s and the Stability and Growth Pact’s role as a monitoring mechanism, allowing them to become more informative tools for the policy makers. For this, based on the relevant literature, we propose new potential explanatory variables which could enhance the role of the Maastricht convergence criteria and the Stability and Growth Pact. Some of the studied variables, like indebtedness of the private sector, capital flow compared to the size of the economy, government revenue compared to total public debt and current account balance help in enforcing the nominal convergence, while others (real labour productivity contribute to the real convergence. The explanatory power of the proposed variables are investigated in the case of France, Germany, Greece, Ireland, Italy, Portugal and Spain for the period comprised between 2000Q1-2011Q4. Results of the research show that with the exception of government revenue compared to total public debt, all proposed variables have significant explanatory power regarding the evolution of the state of the economy in all

  4. Convergent systems vs. incremental stability

    NARCIS (Netherlands)

    Rüffer, B.S.; Wouw, van de N.; Mueller, M.

    2013-01-01

    Two similar stability notions are considered; one is the long established notion of convergent systems, the other is the younger notion of incremental stability. Both notions require that any two solutions of a system converge to each other. Yet these stability concepts are different, in the sense

  5. Giant lobelias exemplify convergent evolution

    Directory of Open Access Journals (Sweden)

    Givnish Thomas J

    2010-01-01

    Full Text Available Abstract Giant lobeliads on tropical mountains in East Africa and Hawaii have highly unusual, giant-rosette growth forms that appear to be convergent on each other and on those of several independently evolved groups of Asteraceae and other families. A recent phylogenetic analysis by Antonelli, based on sequencing the widest selection of lobeliads to date, raises doubts about this paradigmatic example of convergent evolution. Here I address the kinds of evidence needed to test for convergent evolution and argue that the analysis by Antonelli fails on four points. Antonelli's analysis makes several important contributions to our understanding of lobeliad evolution and geographic spread, but his claim regarding convergence appears to be invalid. Giant lobeliads in Hawaii and Africa represent paradigmatic examples of convergent evolution.

  6. CONVERGENCE OF TECHNOLOGIES

    Directory of Open Access Journals (Sweden)

    R. Siriram

    2012-01-01

    Full Text Available

    ENGLISH ABSTRACT: Technology is a catalyst for competitive advantage. However, it is how technology is used that leads to a firm’s improved performance. In this article, an investigative framework is constructed to understand better what strategically drives new technology adoption. The strategic drivers include technology and business strategy alignment, better technology planning and selection of new technologies, the effects on a firm’s culture and climate, links to a firm’s organisational and environmental evolution, and benefits through convergence and collaboration. Using an investigative framework, it is shown how the strategic drivers link to improve a firm’s performance, producing competitive advantage. The investigative framework is tested using structural equation modelling. Various hypotheses are formed, and recommendations for further research are made.

    AFRIKAANSE OPSOMMING: Tegnologie is ‘n katalisator vir mededingende voordeel. Dit is egter hoe tegnologie aangewend word wat aanleiding gee tot ‘n onderneming se verbeterde prestasie. In hierdie artikel word ‘n ondersoekende raamwerk gekonstrueer om insig te kry in dit wat die aanvaarding van nuwe tegnologie strategies dryf. Die strategiese dryfvere sluit in die belyning van tegnologie en ondernemingstrategie, beter tegnologiebeplanning en seleksie van nuwe tegnologieë, die effek op ‘n onderneming se kultuur en klimaat, koppeling na ‘n onderneming se organisatoriese en omgewingsevolusie, en voordele verkry deur konvergensie en samewerking. Deur ‘n ondersoekende raamwerk te gebruik, word daar getoon dat die strategiese dryfvere koppel om ‘n onderneming se prestasie te verbeter en sodoende ‘n mededingende voordeel te skep. Die raamwerk word getoets en hipoteses geformuleer waarna aanbevelings oor verdere navorsing aan die hand gedoen word.

  7. The Convergence in Spatial Tasks

    Directory of Open Access Journals (Sweden)

    Vladimir P. Kulagin

    2013-01-01

    Full Text Available The article reveals the problem of convergence of direct and inverse problems in Earth Sciences, describes the features and application of these problems, discloses analytical features of direct and inverse problems. The convergence criteria and conditions for convergence were presented. This work is supported by the Grant of the Government of the Russian Federation for support of scientific research, implemented under the supervision of leading scientists in Russian institutions of higher education in the field "Space Research and Technologies" in 2011–2013.

  8. Ecomorphological convergence in planktivorous surgeonfishes

    KAUST Repository

    Friedman, S. T.; Price, S. A.; Hoey, Andrew; Wainwright, P. C.

    2016-01-01

    two diet regimes: zooplanktivores and nonzooplanktivorous grazers. Accounting for phylogenetic relationships, the best-fitting model indicates that zooplanktivorous species are converging on a separate adaptive peak from their grazing relatives

  9. Weak entropy inequalities and entropic convergence

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A criterion for algebraic convergence of the entropy is presented and an algebraic convergence result for the entropy of an exclusion process is improved. A weak entropy inequality is considered and its relationship to entropic convergence is discussed.

  10. Cultura da Convergência

    Directory of Open Access Journals (Sweden)

    Rogério Christofoletti

    2008-12-01

    Full Text Available Três idéias já seriam suficientes para que a leitura de “Culturada Convergência”, de Henry Jenkins, interessasse a jornalistas epesquisadores da área: a convergência midiática como um processo cultural; o fortalecimento de uma economia afetiva que orienta consumidores de bens simbólicos e criadores midiáticos; a expansão de formas narrativas transmidiáticas.

  11. Globalization and Contemporary Fertility Convergence.

    Science.gov (United States)

    Hendi, Arun S

    2017-09-01

    The rise of the global network of nation-states has precipitated social transformations throughout the world. This article examines the role of political and economic globalization in driving fertility convergence across countries between 1965 and 2009. While past research has typically conceptualized fertility change as a country-level process, this study instead employs a theoretical and methodological framework that examines differences in fertility between pairs of countries over time. Convergence in fertility between pairs of countries is hypothesized to result from increased cross-country connectedness and cross-national transmission of fertility-related schemas. I investigate the impact of various cross-country ties, including ties through bilateral trade, intergovernmental organizations, and regional trade blocs, on fertility convergence. I find that globalization acts as a form of social interaction to produce fertility convergence. There is significant heterogeneity in the effects of different cross-country ties. In particular, trade with rich model countries, joint participation in the UN and UNESCO, and joining a free trade agreement all contribute to fertility convergence between countries. Whereas the prevailing focus in fertility research has been on factors producing fertility declines, this analysis highlights specific mechanisms-trade and connectedness through organizations-leading to greater similarity in fertility across countries. Globalization is a process that propels the spread of culturally laden goods and schemas impinging on fertility, which in turn produces fertility convergence.

  12. Projected Response of Low-Level Convergence and Associated Precipitation to Greenhouse Warming

    Science.gov (United States)

    Weller, Evan; Jakob, Christian; Reeder, Michael J.

    2017-10-01

    The parameterization of convection in climate models is a large source of uncertainty in projecting future precipitation changes. Here an objective method to identify organized low-level convergence lines has been used to better understand how atmospheric convection is organized and projected to change, as low-level convergence plays an important role in the processes leading to precipitation. The frequency and strength of convergence lines over both ocean and land in current climate simulations is too low compared to reanalysis data. Projections show a further reduction in the frequency and strength of convergence lines over the midlatitudes. In the tropics, the largest changes in frequency are generally associated with shifts in major low-latitude convergence zones, consistent with changes in the precipitation. Further, examining convergence lines when in the presence or absence of precipitation results in large spatial contrasts, providing a better understanding of regional changes in terms of thermodynamic and dynamic effects.

  13. Trophic convergence drives morphological convergence in marine tetrapods.

    Science.gov (United States)

    Kelley, Neil P; Motani, Ryosuke

    2015-01-01

    Marine tetrapod clades (e.g. seals, whales) independently adapted to marine life through the Mesozoic and Caenozoic, and provide iconic examples of convergent evolution. Apparent morphological convergence is often explained as the result of adaptation to similar ecological niches. However, quantitative tests of this hypothesis are uncommon. We use dietary data to classify the feeding ecology of extant marine tetrapods and identify patterns in skull and tooth morphology that discriminate trophic groups across clades. Mapping these patterns onto phylogeny reveals coordinated evolutionary shifts in diet and morphology in different marine tetrapod lineages. Similarities in morphology between species with similar diets-even across large phylogenetic distances-are consistent with previous hypotheses that shared functional constraints drive convergent evolution in marine tetrapods.

  14. Digital Convergence and Content Regulation

    Directory of Open Access Journals (Sweden)

    Michael John Starks

    2014-12-01

    Full Text Available Broadcasting, Press and Internet journalism systems of distribution are converging: the same infrastructure can deliver all three historically separate services. Reception devices mirror this: the Connected TV, the tablet and the smart phone overlap in their functionality. Service overlaps are evident too, with broadcasters providing online and on-demand services and newspapers developing electronic versions. Does this mean that media regulation policies must converge too?My argument is that they should, though only where historically different communications are now fulfilling a similar function, e.g. broadcaster online services and electronic versions of newspapers. Convergence requires a degree of harmonisation and, to this end, I advocate a review of UK broadcasting's 'due impartiality' requirement and of the UK's application of the public service concept. I also argue for independent self-regulation (rather than state-based regulation of non-public-service broadcasting journalism.

  15. Cultura da Convergência

    Directory of Open Access Journals (Sweden)

    Rogério Christofoletti

    2008-12-01

    Full Text Available Três idéias já seriam suficientes para que a leitura de “Cultura da Convergência”, de Henry Jenkins, interessasse a jornalistas e pesquisadores da área: a convergência midiática como um processo cultural; o fortalecimento de uma economia afetiva que orienta consumidores de bens simbólicos e criadores midiáticos; a expansão de formas narrativas transmidiáticas.

  16. Hyporheic Microbes Database - Microbes in the hyporheic zone

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The hyporheic zone (i.e., where surface & groundwater converge) is a geomorphic feature that contributes to the overall health of streams & rivers. Much of...

  17. Convergence accommodation to convergence CA/C ratio: convergence versus divergence.

    Science.gov (United States)

    Simmons, Joshua M; Firth, Alison Y

    2014-09-01

    To determine whether the convergence accommodation to convergence (CA/C) ratio during divergence with base-in (BI) prisms is of a similar or different magnitude to that measured during convergence with base-out (BO) prisms. Eighteen participants with normal binocular single vision were recruited. The participants viewed a pseudo-Gaussian target, which consisted of a light emitting diode (LED) behind a diffusing screen at 40 cm. After 5 minutes of dark adaptation, the refractive status of the eye was measured without any prism using a Shin-Nippon SRW-5000 autorefractor. The participant held the selected prism (5Δ or 10Δ BO or BI, counterbalanced) in front of their right eye and obtained a single, fused image of the target while refractive measures were taken with each. A 30-second rest period was given between measurements. The mean age of the participants was 20.6±3.22 years. The mean CA/C ratios for the 5Δ BO, 10Δ BO, 5Δ BI, and 10Δ BI were 0.108 (±0.074) D/Δ, 0.110 (±0.056) D/Δ, 0.100 (±0.090) D/Δ, and 0.089 (±0.055) D/Δ, respectively. A 2-factor repeated measures ANOVA found that the CA/C ratio did not significantly change with differing levels of prism-induced convergence and divergence (p=0.649). Change in accommodation induced by manipulating vergence is similar whether convergence or divergence are induced. The CA/C ratio did not show any change with differing levels of prism-induced convergence and divergence.

  18. Design of convergent switched systems

    NARCIS (Netherlands)

    Berg, van den R.A.; Pogromsky, A.Y.; Leonov, G.A.; Rooda, J.E.; Pettersen, K.Y.; Gravdahl, J.T.; Nijmeijer, H.

    2006-01-01

    In this paper we deal with the problem of rendering hybrid/nonlinear systems into convergent closed-loop systems by means of a feedback law or switching rules. We illustrate our approach to this problem by means of two examples: the anti-windup design for a marginally stable system with input

  19. Convergence Patterns in Latin America

    DEFF Research Database (Denmark)

    Quiroga, Paola Andrea Barrientos

    characteristics, and external shocks in the region. I study three important phases, following Thorp (1998): from 1900 to 1930, the exporting phase, from 1931 to 1974, the industrialization phase, and from 1975 to 2007, the globalization phase. During the last two phases, I find strong evidence of convergence...

  20. Convergence of a Catalan Series

    Science.gov (United States)

    Koshy, Thomas; Gao, Zhenguang

    2012-01-01

    This article studies the convergence of the infinite series of the reciprocals of the Catalan numbers. We extract the sum of the series as well as some related ones, illustrating the power of the calculus in the study of the Catalan numbers.

  1. Digital Convergence and Content Regulation

    NARCIS (Netherlands)

    Starks, Michael John

    2014-01-01

    abstractBroadcasting, Press and Internet journalism systems of distribution are converging: the same infrastructure can deliver all three historically separate services. Reception devices mirror this: the Connected TV, the tablet and the smart phone overlap in their functionality. Service overlaps

  2. Convergence and migration among provinces.

    Science.gov (United States)

    Helliwell, J F

    1996-04-01

    "Have regional disparities in Canada changed over the past thirty years? This paper assesses the robustness of earlier findings of convergence in the levels and growth rates of provincial per capita GDP, and then estimates the extent to which interprovincial and international migration is being influenced by regional differences in incomes and employment." excerpt

  3. Revisiting convergence: A research note.

    Science.gov (United States)

    Clark, Rob

    2015-09-01

    A number of recent studies show that income inequality is declining between countries. In this research note, I question the significance of this trend by examining the role of initial conditions in producing convergence. An important (but neglected) property of inequality dynamics is the tendency for extreme distributions to become more moderate. When income disparities are large, the subsequent trend is biased toward convergence. Conversely, when initial conditions approach parity, divergence becomes the more likely long-term outcome. I apply this principle to trends in GDP PC across 127 countries during the 1980-2010 period. Using counterfactual analysis, I manipulate the initial level of inequality in GDP PC while holding constant each country's observed growth rate during the sample period. I find that the growth dynamics of GDP PC produce either convergence or divergence based simply on the initial distribution of income. The point of transition occurs at a moderate level of inequality, whether using population weights (Gini=.365) or not (Gini=.377). I conclude that the recent convergence observed in GDP PC is primarily a function of large income gaps between countries and would not have materialized at more moderate levels of initial inequality. By contrast, an examination of the pre-1950 period reveals divergent growth patterns that are not sensitive to initial conditions. Copyright © 2015 Elsevier Inc. All rights reserved.

  4. Industrial Evolution Through Complementary Convergence

    DEFF Research Database (Denmark)

    Frøslev Christensen, Jens

    2011-01-01

    The article addresses the dynamics through which product markets become derailed from early product life cycle (PLC)-tracks and engaged in complementary convergence with other product markets or industries. We compare and contrast the theories that can explain, respectively, the PLC...

  5. Privatization, convergence, and institutional autonomy

    NARCIS (Netherlands)

    Rooijen, van M.

    2011-01-01

    Some of the trends incoming for 2011 – greater institutional autonomy, public/private convergence, entrepreneurial management, civic engagement – suggest innovation for hard times, with socio-economic and political rationales increasingly driving borderless developments. Others – open learning and

  6. Converging Information and Communication Systems

    DEFF Research Database (Denmark)

    Øst, Alexander

    2003-01-01

    in the future to have - significant importance to the process and consequences of the convergence. The project focuses on the appliances, i.e. the TV sets, the computers and their peripheral equipment. It also takes into account the infrastructure and signals, which contain and deliver the information...

  7. Evolution and convergence in telecommunications

    Energy Technology Data Exchange (ETDEWEB)

    Radicella, S; Grilli, D [Abdus Salam ICTP, Trieste (Italy)

    2002-12-15

    These lectures throw a spotlight on different aspects of the evolution of telecommunications networks, namely on the various facets of service and network convergence. The last years progress in data and telecommunications technologies, such as P-based networks, and the enormous potential of mobile communication systems and users' demands for comprehensive and network-independent have led to a convergence of data and telecommunications infrastructures in many aspects. In order to help the reader to an easier understanding of the phenomenon convergence, in the first two parts of this volume the evolution of the basic technologies is described one by one. This is done briefly and is focused on the principle topics, just to build a basis for the third part devoted to problems of convergence in telecommunications. These notes are addressed to those readers, who in a quick overview want to be informed on the future service and network landscape. The notes are equally suited for professionals with the desire to extend their horizon as well as for students looking for an introduction into telecommunications under more general aspects. The authors clearly understand the difficulties in writing a book devoted to the evolution in telecommunications. Today, telecom landscape varies at very high speed. Every few months new network technologies, new products and new services are developed. Attempts to present them in time can be accessible only for magazine publications or contributions to conferences. Therefore, in a number of areas, such as Voice over IP and new switching technologies not much more than the starting point of new paradigms is described. However, the content is up-to-date to a degree, that the phenomenon convergence can be fully understood. Partially, these notes are based on a number of lecture courses that were delivered during recent ICTP winter schools devoted to multimedia and digital communications.

  8. Evolution and convergence in telecommunications

    International Nuclear Information System (INIS)

    Radicella, S.; Grilli, D.

    2002-01-01

    These lectures throw a spotlight on different aspects of the evolution of telecommunications networks, namely on the various facets of service and network convergence. The last years progress in data and telecommunications technologies, such as P-based networks, and the enormous potential of mobile communication systems and users' demands for comprehensive and network-independent have led to a convergence of data and telecommunications infrastructures in many aspects. In order to help the reader to an easier understanding of the phenomenon convergence, in the first two parts of this volume the evolution of the basic technologies is described one by one. This is done briefly and is focused on the principle topics, just to build a basis for the third part devoted to problems of convergence in telecommunications. These notes are addressed to those readers, who in a quick overview want to be informed on the future service and network landscape. The notes are equally suited for professionals with the desire to extend their horizon as well as for students looking for an introduction into telecommunications under more general aspects. The authors clearly understand the difficulties in writing a book devoted to the evolution in telecommunications. Today, telecom landscape varies at very high speed. Every few months new network technologies, new products and new services are developed. Attempts to present them in time can be accessible only for magazine publications or contributions to conferences. Therefore, in a number of areas, such as Voice over IP and new switching technologies not much more than the starting point of new paradigms is described. However, the content is up-to-date to a degree, that the phenomenon convergence can be fully understood. Partially, these notes are based on a number of lecture courses that were delivered during recent ICTP winter schools devoted to multimedia and digital communications

  9. Convergences

    International Nuclear Information System (INIS)

    Glashow, S.L.

    1976-01-01

    These are scattered remarks concerning what is happening to (not in) elementary particle physics. New developments are unfolding with unprecedented speed, so that one does not even attempt to give a comprehensive review at this time. Mostly charm is discussed, both its phenomenology and its impact on belief in quarks, chromodynamics, and unified theories. Beneath the newsworthy experimental discoveries of the last two years lies a quieter and more profound theoretical development: the emergence of a theory of particle physics

  10. Quantifying convergence in the sciences

    Directory of Open Access Journals (Sweden)

    Sara Lumbreras

    2016-02-01

    Full Text Available Traditional epistemological models classify knowledge into separate disciplines with different objects of study and specific techniques, with some frameworks even proposing hierarchies (such as Comte’s. According to thinkers such as John Holland or Teilhard de Chardin, the advancement of science involves the convergence of disciplines. This proposed convergence can be studied in a number of ways, such as how works impact research outside a specific area (citation networks or how authors collaborate with other researchers in different fields (collaboration networks. While these studies are delivering significant new insights, they cannot easily show the convergence of different topics within a body of knowledge. This paper attempts to address this question in a quantitative manner, searching for evidence that supports the idea of convergence in the content of the sciences themselves (that is, whether the sciences are dealing with increasingly the same topics. We use Latent Dirichlet Analysis (LDA, a technique that is able to analyze texts and estimate the relative contributions of the topics that were used to generate them. We apply this tool to the corpus of the Santa Fe Institute (SFI working papers, which spans research on Complexity Science from 1989 to 2015. We then analyze the relatedness of the different research areas, the rise and demise of these sub-disciplines over time and, more broadly, the convergence of the research body as a whole. Combining the topic structure obtained from the collected publication history of the SFI community with techniques to infer hierarchy and clustering, we reconstruct a picture of a dynamic community which experiences trends, periodically recurring topics, and shifts in the closeness of scholarship over time. We find that there is support for convergence, and that the application of quantitative methods such as LDA to the study of knowledge can provide valuable insights that can help

  11. Economic convergence and climate policy

    International Nuclear Information System (INIS)

    Ciscar, J.C.; Soria, A.

    2000-01-01

    This paper addresses the relevance of the economic convergence hypotheses between the developing and the developed world in international greenhouse gas (GHG) emissions negotiations. The results are based on a two-region (the OECD and the rest of the world, ROW) neo-classical growth model with exogenous technical progress, different technological diffusion patterns, and a set of geophysical relationships that consider an environmental externality linked to GHG emissions. A game framework is taken into account in the model to capture the strategic interactions between agents. The outcome of the negotiations seems indeed to depend on the economic convergence hypotheses. Faster economic growth of the ROW countries would encourage them to further mitigate carbon emissions. (Author)

  12. Converging-barrel plasma accelerator

    International Nuclear Information System (INIS)

    Paine, T.O.

    1971-01-01

    The invention comprises a device for generating and accelerating plasma to extremely high velocity, while focusing the plasma to a decreasing cross section for attaining a very dense high-velocity plasma burst capable of causing nuclear fusion reactions. A converging coaxial accelerator-electrode configuration is employed with ''high-pressure'' gas injection in controlled amounts to achieve acceleration by deflagration and focusing by the shaped electromagnetic fields. (U.S.)

  13. Rapid Convergence and Subduction at the Intersections of Fronts

    Science.gov (United States)

    D'Asaro, E. A.

    2016-12-01

    An array of 300 surface drifters drogued to follow the top 0.6m of the ocean were deployed in the northern Gulf of Mexico near the Deep Water Horizon spill site in January of 2016. As expected, the array spread from its initial 15x15km scale with the second moment increasing at a rate roughly consistent with historical dispersion curves. More surprisingly, a large fraction of the drifters accumulated within a km-scale submesoscale eddy and grouped into clusters often only a few meters apart. This occurred due to surface convergence, as opposed to purely confluence, with convergence rates of many f feeding downward-going subduction zones with vertical velocities of a few centimeters per second. These convergences preferentially occurred at density fronts and in particular at junctions of density fronts on the periphery of submesoscale eddies. These observations complement the traditional view of lateral dispersion of surface particles by mesoscale eddies with a competing submesocale convergence and provide direct observations of the strong vertical exchanges associated with submesoscale eddies and fronts.

  14. Surface meshing with curvature convergence

    KAUST Repository

    Li, Huibin; Zeng, Wei; Morvan, Jean-Marie; Chen, Liming; Gu, Xianfengdavid

    2014-01-01

    Surface meshing plays a fundamental role in graphics and visualization. Many geometric processing tasks involve solving geometric PDEs on meshes. The numerical stability, convergence rates and approximation errors are largely determined by the mesh qualities. In practice, Delaunay refinement algorithms offer satisfactory solutions to high quality mesh generations. The theoretical proofs for volume based and surface based Delaunay refinement algorithms have been established, but those for conformal parameterization based ones remain wide open. This work focuses on the curvature measure convergence for the conformal parameterization based Delaunay refinement algorithms. Given a metric surface, the proposed approach triangulates its conformal uniformization domain by the planar Delaunay refinement algorithms, and produces a high quality mesh. We give explicit estimates for the Hausdorff distance, the normal deviation, and the differences in curvature measures between the surface and the mesh. In contrast to the conventional results based on volumetric Delaunay refinement, our stronger estimates are independent of the mesh structure and directly guarantee the convergence of curvature measures. Meanwhile, our result on Gaussian curvature measure is intrinsic to the Riemannian metric and independent of the embedding. In practice, our meshing algorithm is much easier to implement and much more efficient. The experimental results verified our theoretical results and demonstrated the efficiency of the meshing algorithm. © 2014 IEEE.

  15. Surface meshing with curvature convergence

    KAUST Repository

    Li, Huibin

    2014-06-01

    Surface meshing plays a fundamental role in graphics and visualization. Many geometric processing tasks involve solving geometric PDEs on meshes. The numerical stability, convergence rates and approximation errors are largely determined by the mesh qualities. In practice, Delaunay refinement algorithms offer satisfactory solutions to high quality mesh generations. The theoretical proofs for volume based and surface based Delaunay refinement algorithms have been established, but those for conformal parameterization based ones remain wide open. This work focuses on the curvature measure convergence for the conformal parameterization based Delaunay refinement algorithms. Given a metric surface, the proposed approach triangulates its conformal uniformization domain by the planar Delaunay refinement algorithms, and produces a high quality mesh. We give explicit estimates for the Hausdorff distance, the normal deviation, and the differences in curvature measures between the surface and the mesh. In contrast to the conventional results based on volumetric Delaunay refinement, our stronger estimates are independent of the mesh structure and directly guarantee the convergence of curvature measures. Meanwhile, our result on Gaussian curvature measure is intrinsic to the Riemannian metric and independent of the embedding. In practice, our meshing algorithm is much easier to implement and much more efficient. The experimental results verified our theoretical results and demonstrated the efficiency of the meshing algorithm. © 2014 IEEE.

  16. Natural gas and electricity convergence

    International Nuclear Information System (INIS)

    Calger, C.

    1998-01-01

    Convergence between the gas and electricity industries was described as a means for creating an increasingly more efficient energy market where prices and fundamental relationships exist between gas and electricity. Convergence creates new opportunities for producers and consumers. Convergence will likely lead to the disaggregation of the electricity and gas industry into segments such as: (1) power generation and production, (2) transmission wires and pipelines, (3) wholesale merchants, (4) distribution wires and pipelines, and (5) retail marketing, services and administration. The de-integration of integrated utilities has already begun in the U.S. energy markets and retail open access is accelerating. This retail competition will create very demanding customers and the changing risk profile will create new issues for stakeholders. The pace of reform for the telecommunications, airlines, natural gas and electricity industries was graphically illustrated to serve as an example of what to expect. The different paths that the industry might take to deregulation (aggressively embrace reform, or defensively blocking it), and the likely consequences of each reaction were also described. A map indicating where U.S. electric and natural gas utility merger and acquisition activities have taken place between 1994-1997, was included. Another map showing the physical asset positions of the Enron grid, one of the largest independent oil and gas companies in the U.S., with increasing international operations, including an electric power transmission and distribution arm, was also provided as an illustration of a fully integrated energy market company of the future. 9 figs

  17. a globally convergent hyperpl onvergent hyperplane

    African Journals Online (AJOL)

    userpc

    Bayero Journal of Pure and App. ISSN 2006 – 6996 ... Globally Convergent Hyper plane-BFGS method for solving nonline. The attractive ... Numerical performance on some b rates there liability ..... convergence of a class of quasi methods on ...

  18. Density by Moduli and Lacunary Statistical Convergence

    Directory of Open Access Journals (Sweden)

    Vinod K. Bhardwaj

    2016-01-01

    Full Text Available We have introduced and studied a new concept of f-lacunary statistical convergence, where f is an unbounded modulus. It is shown that, under certain conditions on a modulus f, the concepts of lacunary strong convergence with respect to a modulus f and f-lacunary statistical convergence are equivalent on bounded sequences. We further characterize those θ for which Sθf=Sf, where Sθf and Sf denote the sets of all f-lacunary statistically convergent sequences and f-statistically convergent sequences, respectively. A general description of inclusion between two arbitrary lacunary methods of f-statistical convergence is given. Finally, we give an Sθf-analog of the Cauchy criterion for convergence and a Tauberian theorem for Sθf-convergence is also proved.

  19. Stable convergence and stable limit theorems

    CERN Document Server

    Häusler, Erich

    2015-01-01

    The authors present a concise but complete exposition of the mathematical theory of stable convergence and give various applications in different areas of probability theory and mathematical statistics to illustrate the usefulness of this concept. Stable convergence holds in many limit theorems of probability theory and statistics – such as the classical central limit theorem – which are usually formulated in terms of convergence in distribution. Originated by Alfred Rényi, the notion of stable convergence is stronger than the classical weak convergence of probability measures. A variety of methods is described which can be used to establish this stronger stable convergence in many limit theorems which were originally formulated only in terms of weak convergence. Naturally, these stronger limit theorems have new and stronger consequences which should not be missed by neglecting the notion of stable convergence. The presentation will be accessible to researchers and advanced students at the master's level...

  20. Technology assessment using NBIC convergence

    International Nuclear Information System (INIS)

    Vaseashta, Ashok

    2009-01-01

    Full text: Notwithstanding progress in the areas of nanotechnology/nanoscience, biotechnology, information technology, and cognitive sciences (NBIC), the synergy arising from convergence of these disciplines offers great potential for transformational, revolutionary, and embryonic opportunities with many technological applications. In addition, advances in synthesis and characterization methods have provided the means to study, understand, control, or even manipulate the transitional characteristics between isolated atoms and bulk material. In recent years, newly developed architectures in nanostructures and nanosystems with improved functionality, and ensuing unique characteristics have been developed with applications in chemical and biological sensors, nanobiotechnology, nanophotonics, and analysis of cellular processes. Novel convergence methodologies will integrate and advance next generation solutions to current and future technical challenges. Convergence in research methodologies transform the way research is conducted by overcoming specific barriers or filling existing knowledge gaps. NBIC Convergence and associated research methodologies has exceptionally high potential for transforming the manner in which state-of-the-art information is gathered, analyzed, and leveraged to enable future advances and applications. Examples of synergy of these disciplines include: label free, highly multiplexed over broad dynamic range, and decentralized nanotechnology based sensor platform for detection of biological and chemical agents; nucleic acid layers in conjunction with nanomaterials-based electrochemical or optical transducers as DNA Biosensor; potential targets for the next generation of vaccines, therapeutics and diagnostics to enhance human performance; basis for 'Gene Ontology' to provides an important link between gene function and systems biology to understand a global picture of host-microbe interactions - to name a few. Since the idea of 'Converging

  1. Statistical convergence on intuitionistic fuzzy normed spaces

    International Nuclear Information System (INIS)

    Karakus, S.; Demirci, K.; Duman, O.

    2008-01-01

    Saadati and Park [Saadati R, Park JH, Chaos, Solitons and Fractals 2006;27:331-44] has recently introduced the notion of intuitionistic fuzzy normed space. In this paper, we study the concept of statistical convergence on intuitionistic fuzzy normed spaces. Then we give a useful characterization for statistically convergent sequences. Furthermore, we display an example such that our method of convergence is stronger than the usual convergence on intuitionistic fuzzy normed spaces

  2. Convergence of barycentric coordinates to barycentric kernels

    KAUST Repository

    Kosinka, Jiří

    2016-02-12

    We investigate the close correspondence between barycentric coordinates and barycentric kernels from the point of view of the limit process when finer and finer polygons converge to a smooth convex domain. We show that any barycentric kernel is the limit of a set of barycentric coordinates and prove that the convergence rate is quadratic. Our convergence analysis extends naturally to barycentric interpolants and mappings induced by barycentric coordinates and kernels. We verify our theoretical convergence results numerically on several examples.

  3. Convergence of barycentric coordinates to barycentric kernels

    KAUST Repository

    Kosinka, Jiří ; Barton, Michael

    2016-01-01

    We investigate the close correspondence between barycentric coordinates and barycentric kernels from the point of view of the limit process when finer and finer polygons converge to a smooth convex domain. We show that any barycentric kernel is the limit of a set of barycentric coordinates and prove that the convergence rate is quadratic. Our convergence analysis extends naturally to barycentric interpolants and mappings induced by barycentric coordinates and kernels. We verify our theoretical convergence results numerically on several examples.

  4. Semantic Convergence in the Bilingual Lexicon

    Science.gov (United States)

    Ameel, Eef; Malt, Barbara C.; Storms, Gert; Van Assche, Fons

    2009-01-01

    Bilinguals' lexical mappings for their two languages have been found to converge toward a common naming pattern. The present paper investigates in more detail how semantic convergence is manifested in bilingual lexical knowledge. We examined how semantic convergence affects the centers and boundaries of lexical categories for common household…

  5. "Nanoselves": NBIC and the Culture of Convergence

    Science.gov (United States)

    Venkatesan, Priya

    2010-01-01

    The subject of this essay is NBIC convergence (nanotechnology, biotechnology, information technology and cognitive science convergence). NBIC convergence is a recurring trope that is dominated by the paradigm of integration of the sciences. It is largely influenced by the considerations of social and economic impact, and it assumes positivism in…

  6. Ecomorphological convergence in planktivorous surgeonfishes

    KAUST Repository

    Friedman, S. T.

    2016-01-26

    © 2016 European Society For Evolutionary Biology. Morphological convergence plays a central role in the study of evolution. Often induced by shared ecological specialization, homoplasy hints at underlying selective pressures and adaptive constraints that deterministically shape the diversification of life. Although midwater zooplanktivory has arisen in adult surgeonfishes (family Acanthuridae) at least four independent times, it represents a clearly specialized state, requiring the capacity to swiftly swim in midwater locating and sucking small prey items. Whereas this diet has commonly been associated with specific functional adaptations in fishes, acanthurids present an interesting case study as all nonplanktivorous species feed by grazing on benthic algae and detritus, requiring a vastly different functional morphology that emphasizes biting behaviours. We examined the feeding morphology in 30 acanthurid species and, combined with a pre-existing phylogenetic tree, compared the fit of evolutionary models across two diet regimes: zooplanktivores and nonzooplanktivorous grazers. Accounting for phylogenetic relationships, the best-fitting model indicates that zooplanktivorous species are converging on a separate adaptive peak from their grazing relatives. Driving this bimodal landscape, zooplanktivorous acanthurids tend to develop a slender body, reduced facial features, smaller teeth and weakened jaw adductor muscles. However, despite these phenotypic changes, model fitting suggests that lineages have not yet reached the adaptive peak associated with plankton feeding even though some transitions appear to be over 10 million years old. These findings demonstrate that the selective demands of pelagic feeding promote repeated - albeit very gradual - ecomorphological convergence within surgeonfishes, while allowing local divergences between closely related species, contributing to the overall diversity of the clade. Journal of Evolutionary Biology

  7. Ecomorphological convergence in planktivorous surgeonfishes.

    Science.gov (United States)

    Friedman, S T; Price, S A; Hoey, A S; Wainwright, P C

    2016-05-01

    Morphological convergence plays a central role in the study of evolution. Often induced by shared ecological specialization, homoplasy hints at underlying selective pressures and adaptive constraints that deterministically shape the diversification of life. Although midwater zooplanktivory has arisen in adult surgeonfishes (family Acanthuridae) at least four independent times, it represents a clearly specialized state, requiring the capacity to swiftly swim in midwater locating and sucking small prey items. Whereas this diet has commonly been associated with specific functional adaptations in fishes, acanthurids present an interesting case study as all nonplanktivorous species feed by grazing on benthic algae and detritus, requiring a vastly different functional morphology that emphasizes biting behaviours. We examined the feeding morphology in 30 acanthurid species and, combined with a pre-existing phylogenetic tree, compared the fit of evolutionary models across two diet regimes: zooplanktivores and nonzooplanktivorous grazers. Accounting for phylogenetic relationships, the best-fitting model indicates that zooplanktivorous species are converging on a separate adaptive peak from their grazing relatives. Driving this bimodal landscape, zooplanktivorous acanthurids tend to develop a slender body, reduced facial features, smaller teeth and weakened jaw adductor muscles. However, despite these phenotypic changes, model fitting suggests that lineages have not yet reached the adaptive peak associated with plankton feeding even though some transitions appear to be over 10 million years old. These findings demonstrate that the selective demands of pelagic feeding promote repeated - albeit very gradual - ecomorphological convergence within surgeonfishes, while allowing local divergences between closely related species, contributing to the overall diversity of the clade. © 2016 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2016 European

  8. Poland’s Public Finance Convergence with the Euro Area

    Directory of Open Access Journals (Sweden)

    Elżbieta Kawecka-Wyrzykowska

    2013-06-01

    Full Text Available Situation of Poland's public finances has been improving. Helped by solid economic growth in 2011, Poland has reduced its budget deficit in line with the Commission's recommendations. Contrary to earlier forecasts, in 2012 it was slightly above the ceiling of 3% of GDP. It should be further reduced to reach in 2015 the level of 1% of GDP in terms structural deficit. The slowdown of the economy in 2012 and probably in 2013 will not make this task easy, however.Public debt has risen steadily over the past few years but level has been in recent times still well below the 60% of GDP ceiling.The national reform programme and the convergence programme were adopted by Poland’s Council of Ministers on 25 April 2012. The convergence programme outlined in an integrated manner the fiscal consolidation efforts, the key structural reforms and the reforms that underpin macroeconomic stabilisation.In the medium to long term, Poland is faced with a number of challenges. A very low labour force participation rate, in particular of women, and the poor quality of vocational training and education are major concerns given an ageing population. The low level of public and private R&D spending, weak links between science and industry and the poor innovation performance call for improvements.Apart from programme of national reforms, crucial for future sustained economic growth and good performance of public finances, an additional factor stimulating activities towards fiscal improvement should be Poland’s participation in a strengthened economic governance architecture recently introduced in the EU.Euro adoption remains an important goal of Polish government. The uncertain situation in the euro zone has, however, postponed adoption of a clear timetable of joining the euro zone. The government decided that an additional condition to join the euro zone, apart from meeting the nominal convergence criteria (and legal conditions not discussed here, is stabilisation of

  9. Convergence estimates in approximation theory

    CERN Document Server

    Gupta, Vijay

    2014-01-01

    The study of linear positive operators is an area of mathematical studies with significant relevance to studies of computer-aided geometric design, numerical analysis, and differential equations. This book focuses on the convergence of linear positive operators in real and complex domains. The theoretical aspects of these operators have been an active area of research over the past few decades. In this volume, authors Gupta and Agarwal explore new and more efficient methods of applying this research to studies in Optimization and Analysis. The text will be of interest to upper-level students seeking an introduction to the field and to researchers developing innovative approaches.

  10. SCORE DIGITAL TECHNOLOGY: THE CONVERGENCE

    Directory of Open Access Journals (Sweden)

    Chernyshov Alexander V.

    2013-12-01

    Full Text Available Explores the role of digital scorewriters in today's culture, education, and music industry and media environment. The main principle of the development of software is not only publishing innovation (relating to the sheet music, and integration into the area of composition, arrangement, education, creative process for works based on digital technology (films, television and radio broadcasting, Internet, audio and video art. Therefore the own convergence of musically-computer technology is a total phenomenon: notation program combined with means MIDI-sequencer, audio and video editor. The article contains the unique interview with the creator of music notation processors.

  11. At the Eve of Convergence?

    DEFF Research Database (Denmark)

    Henriksen, Lars Skov; Zimmer, Annette; Smith, Steven Rathgeb

    . Specifically, we will investigate whether and to what extent social services and health care in these three countries are affected by current changes. With a special focus on nonprofit organizations, we will particularly address the question whether a trend towards convergence of the very different welfare......Due to severe societal, economic and political changes, of which the financial crisis counts prominently, welfare states all over the world are under stress. In our comparative analysis, we will concentrate on specific segments of welfare state activity in Denmark, Germany, and the United States...

  12. Sound Zones

    DEFF Research Database (Denmark)

    Møller, Martin Bo; Olsen, Martin

    2017-01-01

    Sound zones, i.e. spatially confined regions of individual audio content, can be created by appropriate filtering of the desired audio signals reproduced by an array of loudspeakers. The challenge of designing filters for sound zones is twofold: First, the filtered responses should generate...... an acoustic separation between the control regions. Secondly, the pre- and post-ringing as well as spectral deterioration introduced by the filters should be minimized. The tradeoff between acoustic separation and filter ringing is the focus of this paper. A weighted L2-norm penalty is introduced in the sound...

  13. Pointwise convergence of Fourier series

    CERN Document Server

    Arias de Reyna, Juan

    2002-01-01

    This book contains a detailed exposition of Carleson-Hunt theorem following the proof of Carleson: to this day this is the only one giving better bounds. It points out the motivation of every step in the proof. Thus the Carleson-Hunt theorem becomes accessible to any analyst.The book also contains the first detailed exposition of the fine results of Hunt, Sjölin, Soria, etc on the convergence of Fourier Series. Its final chapters present original material. With both Fefferman's proof and the recent one of Lacey and Thiele in print, it becomes more important than ever to understand and compare these two related proofs with that of Carleson and Hunt. These alternative proofs do not yield all the results of the Carleson-Hunt proof. The intention of this monograph is to make Carleson's proof accessible to a wider audience, and to explain its consequences for the pointwise convergence of Fourier series for functions in spaces near $äcal Lü^1$, filling a well-known gap in the literature.

  14. Granite ascent and emplacement during contractional deformation in convergent orogens

    Science.gov (United States)

    Brown, Michael; Solar, Gary S.

    1998-09-01

    Based on a case study in the Central Maine Belt of west-central Maine, U.S.A., it is proposed that crustal-scale shear zone systems provide an effective focussing mechanism for transfer of granite melt through the crust in convergent orogens. During contractional deformation, flow of melt in crustal materials at depths below the brittle-plastic transition is coupled with plastic deformation of these materials. The flow is driven by pressure gradients generated by buoyancy forces and tectonic stresses. Within the oblique-reverse Central Maine Belt shear zone system, stromatic migmatite and concordant to weakly discordant irregular granite sheets occur in zones of higher strain, which suggests percolative flow of melt to form the migmatite leucosomes and viscous flow of melt channelized in sheet-like bodies, possibly along fractures. Cyclic fluctuations of melt pressure may cause instantaneous changes in the effective permeability of the flow network if self-propagating melt-filled tensile and/or dilatant shear fractures are produced due to melt-enhanced embrittlement. Inhomogeneous migmatite and schlieric granite occur in zones of lower strain, which suggests migration of partially-molten material through these zones en masse by granular flow, and channelized flow of melt carrying entrained residue. Founded on the Central Maine Belt case study, we develop a model of melt extraction and ascent using the driving forces, stress conditions and crustal rheologies in convergent, especially transpressive orogens. Ascent of melt becomes inhibited with decreasing depth as the solidus is approached. For intermediate a(H 2O) muscovite-dehydration melting, the water-saturated solidus occurs between 400 and 200 MPa, near the brittle-plastic transition during high- T-low- P metamorphism, where the balance of forces favors (sub-) horizontal fracture propagation. Emplacement of melt may be accommodated by ductile flow and/or stoping of wall rock, and inflation may be accommodated

  15. Convergent Validity of the PUTS

    Directory of Open Access Journals (Sweden)

    Valerie Cathérine Brandt

    2016-04-01

    Full Text Available Premonitory urges are a cardinal feature in Gilles de la Tourette syndrome. Severity of premonitory urges can be assessed with the Premonitory Urge for Tic Disorders Scale (PUTS. However, convergent validity of the measure has been difficult to assess due to the lack of other urge measures.We investigated the relationship between average real-time urge intensity assessed by an in-house developed real-time urge monitor, measuring urge intensity continuously for 5mins on a visual analogue scale, and general urge intensity assessed by the PUTS in 22 adult Tourette patients (mean age 29.8+/- 10.3; 19 male. Additionally, underlying factors of premonitory urges assessed by the PUTS were investigated in the adult sample using factor analysis and were replicated in 40 children and adolescents diagnosed with Tourette syndrome (mean age 12.05 +/- 2.83 SD, 31 male.Cronbach’s alpha for the PUTS10 was acceptable (α = .79 in the adult sample. Convergent validity between average real-time urge intensity scores (as assessed with the real-time urge monitor and the 10-item version of the PUTS (r = .64 and the 9-item version of the PUTS (r = .66 was good. A factor analysis including the 10 items of the PUTS and average real-time urge intensity scores revealed three factors. One factor included the average real-time urge intensity score and appeared to measure urge intensity, while the other two factors can be assumed to reflect the (sensory quality of urges and subjective control, respectively. The factor structure of the 10 PUTS items alone was replicated in a sample of children and adolescents.The results indicate that convergent validity between the PUTS and the real-time urge assessment monitor is good. Furthermore, the results suggest that the PUTS might assess more than one dimension of urges and it may be worthwhile developing different sub-scales of the PUTS assessing premonitory urges in terms of intensity and quality, as well as subjectively

  16. Professional convergence in forensic practice.

    Science.gov (United States)

    Mercer, D; Mason, T; Richman, J

    2001-06-01

    This paper outlines the development and convergence of forensic science and secure psychiatric services in the UK, locating the professionalization of forensic nursing within a complex web of political, economic, and ideological structures. It is suggested that a stagnation of the therapeutic enterprise in high and medium security provision has witnessed an intrusion of medical power into the societal body. Expanding technologies of control and surveillance are discussed in relation to the move from modernity to postmodernity and the ongoing dynamic of medicalized offending. Four aspects of globalization are identified as impacting upon the organization and application of forensic practice: (i) organized capitalism and the exhaustion of the welfare state; (ii) security versus danger and trust versus risk; (iii) science as a meta-language; and (iv) foreclosure as a mechanism of censorship. Finally, as a challenge for the profession, some predictions are offered about the future directions or demise of forensic nursing.

  17. Mosaic convergence of rodent dentitions.

    Directory of Open Access Journals (Sweden)

    Vincent Lazzari

    Full Text Available BACKGROUND: Understanding mechanisms responsible for changes in tooth morphology in the course of evolution is an area of investigation common to both paleontology and developmental biology. Detailed analyses of molar tooth crown shape have shown frequent homoplasia in mammalian evolution, which requires accurate investigation of the evolutionary pathways provided by the fossil record. The necessity of preservation of an effective occlusion has been hypothesized to functionally constrain crown morphological changes and to also facilitate convergent evolution. The Muroidea superfamily constitutes a relevant model for the study of molar crown diversification because it encompasses one third of the extant mammalian biodiversity. METHODOLOGY/PRINCIPAL FINDINGS: Combined microwear and 3D-topographic analyses performed on fossil and extant muroid molars allow for a first quantification of the relationships between changes in crown morphology and functionality of occlusion. Based on an abundant fossil record and on a well resolved phylogeny, our results show that the most derived functional condition associates longitudinal chewing and non interlocking of cusps. This condition has been reached at least 7 times within muroids via two main types of evolutionary pathways each respecting functional continuity. In the first type, the flattening of tooth crown which induces the removal of cusp interlocking occurs before the rotation of the chewing movement. In the second type however, flattening is subsequent to rotation of the chewing movement which can be associated with certain changes in cusp morphology. CONCLUSION/SIGNIFICANCE: The reverse orders of the changes involved in these different pathways reveal a mosaic evolution of mammalian dentition in which direction of chewing and crown shape seem to be partly decoupled. Either can change in respect to strong functional constraints affecting occlusion which thereby limit the number of the possible

  18. Beyond Brainstorming: Exploring Convergence in Teams

    Science.gov (United States)

    Seeber, Isabella; de Vreede, Gert-Jan; Maier, Ronald; Weber, Barbara

    2017-01-01

    Abstract Collaborative brainstorming is often followed by a convergence activity where teams extract the most promising ideas on a useful level of detail from the brainstorming results. Contrary to the wealth of research on electronic brainstorming, there is a dearth of research on convergence. We used experimental methods for an in-depth exploration of two facilitation-based interventions in a convergence activity: attention guidance (focusing participants on procedures to execute a convergence task) and discussion encouragement (engaging participants in conversations to combine knowledge on ideas). Our findings show that both attention guidance and discussion encouragement are correlated with higher convergence quality. We argue that attention guidance’s contribution is in its support of coordination, information processing, and goal specification. Similar, we argue that discussion encouragement’s contribution is in its stimulation of idea clarification and idea combination. Contrary to past research, our findings further show that satisfaction was higher after convergence than after brainstorming. PMID:29399005

  19. Regional Convergence and Sustainable Development in China

    Directory of Open Access Journals (Sweden)

    Fang Yang

    2016-01-01

    Full Text Available Based on the convergence theory of economic growth, this paper extends this concept to the human development index and carries out an empirical analysis of regional development in China between 1997 and 2006. Our research shows that the conditional convergence has been identified. Investment in fixed assets, government expenditure on education, health and infrastructure construction have positive effects on regional convergence of social development. Population weighted analysis of human development index provides support for weak convergence amongst provinces. Analysis of dynamics of regional distribution reveals the club convergence, which indicate two different convergence states. Central China is in the shade and lags behind, giving rise to the so-called “central downfall”. To solve this problem, the “Rise of Central China” Plan is necessary to promote the connection between coastal and inland regions of China and reduce the regional development gap.

  20. convergent methods for calculating thermodynamic Green functions

    OpenAIRE

    Bowen, S. P.; Williams, C. D.; Mancini, J. D.

    1984-01-01

    A convergent method of approximating thermodynamic Green functions is outlined briefly. The method constructs a sequence of approximants which converges independently of the strength of the Hamiltonian's coupling constants. Two new concepts associated with the approximants are introduced: the resolving power of the approximation, and conditional creation (annihilation) operators. These ideas are illustrated on an exactly soluble model and a numerical example. A convergent expression for the s...

  1. On statistical acceleration convergence of double sequences

    Directory of Open Access Journals (Sweden)

    Bipan Hazarika

    2017-04-01

    Full Text Available In this article the notion of statistical acceleration convergence of double sequences in Pringsheim's sense has been introduced. We prove the decompostion theorems for  statistical acceleration convergence of double sequences and some theorems related to that concept have been established using the four dimensional matrix transformations. We provided some examples, where the results of acceleration convergence fails to hold for the statistical cases.

  2. Increasing dominance of IT in ICT convergence

    DEFF Research Database (Denmark)

    Henten, Anders; Tadayoni, Reza

    The aim of the paper is to examine the increasing dominance of IT companies in the converging ICT industry and, on the basis of this development, to contribute to extending the theoretical understanding of market and industry convergence in the ICT area.......The aim of the paper is to examine the increasing dominance of IT companies in the converging ICT industry and, on the basis of this development, to contribute to extending the theoretical understanding of market and industry convergence in the ICT area....

  3. Convergence as conditionant for Media Regulation

    Directory of Open Access Journals (Sweden)

    Othon Jambeiro

    2011-01-01

    Full Text Available Convergence comprises a combination of interlinked and interdependent transformations, of technological, industrial, commercial, cultural and social nature, which affect communication regulation. Customers, at their time, turned also convergent, involved in an intense participative culture, which is too, from the point of view of its social and geographical range, thanks to convergence, more and more extense. Instead of passive consumers of media and information and communication services, we have now active and socially connected consumers, no more readers/spectators/listeners, but noisy activists and publishers. To understand this phenomenon is essential to discern a regulatory frame suitable for it. This paper tries to define convergence and to discuss its consequences.

  4. Quadratically convergent MCSCF scheme using Fock operators

    International Nuclear Information System (INIS)

    Das, G.

    1981-01-01

    A quadratically convergent formulation of the MCSCF method using Fock operators is presented. Among its advantages the present formulation is quadratically convergent unlike the earlier ones based on Fock operators. In contrast to other quadratically convergent schemes as well as the one based on generalized Brillouin's theorem, this method leads easily to a hybrid scheme where the weakly coupled orbitals (such as the core) are handled purely by Fock equations, while the rest of the orbitals are treated by a quadratically convergent approach with a truncated virtual space obtained by the use of the corresponding Fock equations

  5. Coastal zone

    International Nuclear Information System (INIS)

    2002-01-01

    The report entitled Climate Change Impacts and Adaptation : A Canadian Perspective, presents a summary of research regarding the impacts of climate change on key sectors over the past five years as it relates to Canada. This chapter on the coastal zone focuses on the impact of climate change on Canada's marine and Great Lakes coasts with tips on how to deal with the impacts associated with climate change in sensitive environments. This report is aimed at the sectors that will be most affected by adaptation decisions in the coastal zone, including fisheries, tourism, transportation and water resources. The impact of climate change in the coastal zone may include changes in water levels, wave patterns, storm surges, and thickness of seasonal ice cover. The Intergovernmental Panel on Climate Change projects global average sea level will rise between 9 and 88 centimetres between 1990 to 2100, but not all areas of Canada will experience the same rate of future sea level change. The main physical impact would be shoreline change that could result in a range of biophysical and socio-economic impacts, some beneficial, some negative. The report focuses on issues related to infrastructure and communities in coastal regions. It is noted that appropriate human adaptation will play a vital role in reducing the extent of potential impacts by decreasing the vulnerability of average zone to climate change. The 3 main trends in coastal adaptation include: (1) increase in soft protection, retreat and accommodation, (2) reliance on technology such as geographic information systems to manage information, and (3) awareness of the need for coastal adaptation that is appropriate for local conditions. 61 refs., 7 figs

  6. Oblique convergence and the lobate mountain belts of western Pakistan

    Science.gov (United States)

    Haq, Saad S. B.; Davis, Dan M.

    1997-01-01

    The thin-skinned structures of the Pakistani convergent margin have formed as a consequence of the relative motion between India and Eurasia. Most of the resultant motion is being accommodated along or near the current edge of the Eurasian plate: the southwest-northeast striking Chaman fault zone. It has been observed at oblique margins that the total plate motion is resolved into a component parallel to the margin, accommodated through strike-slip faulting, and a component normal to the margin taken up as contraction. However, the orientations of structures along the Pakistani convergent margin in and around the Sulaiman lobe and Sulaiman Range cannot be explained simply by resolving the plate motion vector into components normal and parallel to the plate boundary. Our modeling suggests that the complex juxtaposition of strike-slip faults with thrust faults of various orientations can be explained by the presence of a block centered upon the Katawaz basin that translates along the southwest-northeast structural barrier of the Chaman fault zone, moving with respect to both Eurasia and India. As this relatively rigid block moves northeastward relative to Asia, it causes deformation of the sedimentary cover and is responsible for much of the structural complexity in the Pakistani foreland. Our simple model explains several first-order features of this oblique margin, such as the eastward-facing Sulaiman Range, the strike-slip Kingri fault (located between the Sulaiman lobe and Sulaiman Range), and the reentrant at Sibi. This leads us to conclude that very complex structural and geometric relationships at oblique convergent plate boundaries can result from the accommodation of strain with simple initial geometric constraints.

  7. Geophysical constraints on geodynamic processes at convergent margins: A global perspective

    Science.gov (United States)

    Artemieva, Irina; Thybo, Hans; Shulgin, Alexey

    2016-04-01

    Convergent margins, being the boundaries between colliding lithospheric plates, form the most disastrous areas in the world due to intensive, strong seismicity and volcanism. We review global geophysical data in order to illustrate the effects of the plate tectonic processes at convergent margins on the crustal and upper mantle structure, seismicity, and geometry of subducting slab. We present global maps of free-air and Bouguer gravity anomalies, heat flow, seismicity, seismic Vs anomalies in the upper mantle, and plate convergence rate, as well as 20 profiles across different convergent margins. A global analysis of these data for three types of convergent margins, formed by ocean-ocean, ocean-continent, and continent-continent collisions, allows us to recognize the following patterns. (1) Plate convergence rate depends on the type of convergent margins and it is significantly larger when, at least, one of the plates is oceanic. However, the oldest oceanic plate in the Pacific ocean has the smallest convergence rate. (2) The presence of an oceanic plate is, in general, required for generation of high-magnitude (M N 8.0) earthquakes and for generating intermediate and deep seismicity along the convergent margins. When oceanic slabs subduct beneath a continent, a gap in the seismogenic zone exists at depths between ca. 250 km and 500 km. Given that the seismogenic zone terminates at ca. 200 km depth in case of continent-continent collision, we propose oceanic origin of subducting slabs beneath the Zagros, the Pamir, and the Vrancea zone. (3) Dip angle of the subducting slab in continent-ocean collision does not correlate neither with the age of subducting oceanic slab, nor with the convergence rate. For ocean-ocean subduction, clear trends are recognized: steeply dipping slabs are characteristic of young subducting plates and of oceanic plates with high convergence rate, with slab rotation towards a near-vertical dip angle at depths below ca. 500 km at very high

  8. The Convergence of European Business Cycles 1980--2004

    Science.gov (United States)

    Ormerod, P.

    2005-09-01

    The degree of convergence of the business cycles of the economies of the European Union is a key policy issue. In particular, a substantial degree of convergence is needed if the European Central Bank is to be capable of setting a monetary policy which is appropriate to the stage of the cycle of the Euro zone economies. I consider the annual rates of real GDP growth on a quarterly basis in the main economies of the EU (France, Germany, Italy, UK, Spain, Belgium and the Netherlands) over the period 1980Q1--2004Q4. An important empirical question is the degree to which the correlations between these growth rates contain true information rather than noise. The technique of random matrix theory is able to answer this question, and has been applied successfully in the physics journals to financial markets data. I find that the correlations between the growth rates of most of the core EU economies contain substantial amounts of true information, and exhibit considerable stability over time. Even in the late 1970s and early 1980s, these economies moved together closely over the course of the business cycle. There was a slight loosening at the time of German re-unification, but the economies have moved back into close synchronisation. The same result holds when Spain is added to the group of core EU countries. However, the problems of the German economy which arose from the early 1990s onwards has led to Germany becoming increasingly less synchronised with the rest of the core EU. Further, the results obtained with a data set of the converged EU core plus the UK show no real convergence between the UK and this group of economies.

  9. Societal response to nanotechnology: converging technologies–converging societal response research?

    NARCIS (Netherlands)

    Ronteltap, A.; Fischer, A.R.H.; Tobi, H.

    2011-01-01

    Nanotechnology is an emerging technology particularly vulnerable to societal unrest, which may hinder its further development. With the increasing convergence of several technological domains in the field of nanotechnology, so too could convergence of social science methods help to anticipate

  10. Temporal Convergence for Knowledge Management

    Directory of Open Access Journals (Sweden)

    Christopher Phillip Martin

    2008-05-01

    Full Text Available Time and knowledge have tended to be conceptualised in conventional knowledge management systems as either ‘timeless’ recordings of procedures, or time-stamped records of past events and states. The concept of temporal convergence was previously developed to help apply knowledge-management theory to complex military processes such as commander’s intent, shared situation awareness, and self-synchronisation. This paper clarifies the concept and introduces several others in forming a framework to assist discussion and exploration of the types of knowledge required for complex endeavours, such as warfighting, characterised by opposition and uncertainty. The approach is grounded in a pragmatist philosophy and constructivist epistemology. Argument proceeds along mathematical lines from a basis that the types of knowledge most valuable to goal-directed agents in uncertain environments can be modelled as directed graph topologies. The framework is shown to be useful in describing and reasoning about the knowledge requirements and prerequisites for distributed decision-making through the sharing of situational knowledge and common intentions, with practical application to the planning and execution of operations. To the designers of knowledge management systems seeking to address this space, it presents a challenge that cannot be addressed merely by construction, storage, search and retrieval of documents and records pertaining to the past.

  11. Escalated convergent artificial bee colony

    Science.gov (United States)

    Jadon, Shimpi Singh; Bansal, Jagdish Chand; Tiwari, Ritu

    2016-03-01

    Artificial bee colony (ABC) optimisation algorithm is a recent, fast and easy-to-implement population-based meta heuristic for optimisation. ABC has been proved a rival algorithm with some popular swarm intelligence-based algorithms such as particle swarm optimisation, firefly algorithm and ant colony optimisation. The solution search equation of ABC is influenced by a random quantity which helps its search process in exploration at the cost of exploitation. In order to find a fast convergent behaviour of ABC while exploitation capability is maintained, in this paper basic ABC is modified in two ways. First, to improve exploitation capability, two local search strategies, namely classical unidimensional local search and levy flight random walk-based local search are incorporated with ABC. Furthermore, a new solution search strategy, namely stochastic diffusion scout search is proposed and incorporated into the scout bee phase to provide more chance to abandon solution to improve itself. Efficiency of the proposed algorithm is tested on 20 benchmark test functions of different complexities and characteristics. Results are very promising and they prove it to be a competitive algorithm in the field of swarm intelligence-based algorithms.

  12. Europe of energy: convergencies - complexity

    International Nuclear Information System (INIS)

    Chevalier, J.M. and others

    2001-01-01

    This issue of 'Economies et Societes' journal comprises 16 articles dealing with the evolution of European energy markets: the security of European petroleum supplies (P.R. Bauquis); the security of European natural gas supplies (J.M. Dauger); an empirical analysis of the power prices convergence in the European union (J.A. Vega-Cervera, A. Jurado-Malaga); the integration of European power markets, from the juxtaposition of national market to the establishment of a regional market (D. Finon); the fusions-acquisitions in the energy sector and the globalization impact (C.A. Michalet); the reorganization of power economics and the share of right (M.A. Frison-Roche); the European industry facing the new economy (J.M. Chevalier); the confidence stake of the traditional power operators (Y. Benamour, A. Bonanni); status and prospects of gas prices in continental Europe (G. Bellec); the gas and power transport challenges and the access charges fixing (L. David, J. Percebois); the strategic challenges of underground storage in the new European gas context (B. Esnault); stranded costs and deregulation of power networks: some questions raised by the US experience (J. Bezzina); natural gas in Europe and the emergence of spot markets and trading hubs (G. Heyvaert); the competitiveness of the power exchange market of the Netherlands (F. Boisseleau); setting up and de-regulated trades in European markets (H. Geman); the Californian power market (P.L. Joskow). (J.S.)

  13. The long road to convergence and back. Convergence and crossmedia journalism at Dutch Newsmedia

    NARCIS (Netherlands)

    Tameling, Klaske; Broersma, Marcel

    2012-01-01

    KLASKE TAMELING & MARCEL BROERSMA The long road to convergence and back. Convergence and crossmedia journalism at Dutch Newsmedia Since the end of the twentieth century, convergence and cross-media journalism are concepts that are widely used to guide the future of journalism world wide. This study

  14. Frequency response functions for nonlinear convergent systems

    NARCIS (Netherlands)

    Pavlov, A.V.; Wouw, van de N.; Nijmeijer, H.

    2007-01-01

    Convergent systems constitute a practically important class of nonlinear systems that extends the class of asymptotically stable linear time-invariant systems. In this note, we extend frequency response functions defined for linear systems to nonlinear convergent systems. Such nonlinear frequency

  15. Beyond Brainstorming: Exploring Convergence in Teams

    DEFF Research Database (Denmark)

    Seeber, Isabella; de Vreede, Gert-Jan; Maier, Ronald

    2017-01-01

    Collaborative brainstorming is often followed by a convergence activity where teams extract the most promising ideas on a useful level of detail from the brainstorming results. Contrary to the wealth of research on electronic brainstorming, there is a dearth of research on convergence. We used...

  16. Explaining convergence of oecd welfare states

    DEFF Research Database (Denmark)

    Schmitt, C.; Starke, Peter

    2011-01-01

    of conditional convergence helps to both better describe and explain the phenomenon. By applying error correction models, we examine conditional convergence of various types of social expenditure in 21 OECD countries between 1980 and 2005. Our empirical findings go beyond the existing literature in two respects...

  17. New concurrent iterative methods with monotonic convergence

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Qingchuan [Michigan State Univ., East Lansing, MI (United States)

    1996-12-31

    This paper proposes the new concurrent iterative methods without using any derivatives for finding all zeros of polynomials simultaneously. The new methods are of monotonic convergence for both simple and multiple real-zeros of polynomials and are quadratically convergent. The corresponding accelerated concurrent iterative methods are obtained too. The new methods are good candidates for the application in solving symmetric eigenproblems.

  18. Data Convergence - An Australian Perspective

    Science.gov (United States)

    Allen, S. S.; Howell, B.

    2012-12-01

    Coupled numerical physical, biogeochemical and sediment models are increasingly being used as integrators to help understand the cumulative or far field effects of change in the coastal environment. This reliance on modeling has forced observations to be delivered as data streams ingestible by modeling frameworks. This has made it easier to create near real-time or forecasting models than to try to recreate the past, and has lead in turn to the conversion of historical data into data streams to allow them to be ingested by the same frameworks. The model and observation frameworks under development within Australia's Commonwealth and Industrial Research Organisation (CSIRO) are now feeding into the Australian Ocean Data Network's (AODN's) MARine Virtual Laboratory (MARVL) . The sensor, or data stream, brokering solution is centred around the "message" and all data flowing through the gateway is wrapped as a message. Messages consist of a topic and a data object and their routing through the gateway to pre-processors and listeners is determined by the topic. The Sensor Message Gateway (SMG) method is allowing data from different sensors measuring the same thing but with different temporal resolutions, units or spatial coverage to be ingested or visualized seamlessly. At the same time the model output as a virtual sensor is being explored, this again being enabled by the SMG. It is only for two way communications with sensor that rigorous adherence to standards is needed, by accepting existing data in less than ideal formats, but exposing them though the SMG we can move a step closer to the Internet Of Things by creating an Internet of Industries where each vested interest can continue with business as usual, contribute to data convergence and adopt more open standards when investment seems appropriate to that sector or business.Architecture Overview

  19. On the convergence of finite state mean-field games through Γ-convergence

    KAUST Repository

    Ferreira, Rita C.; Gomes, Diogo A.

    2014-01-01

    In this study, we consider the long-term convergence (trend toward an equilibrium) of finite state mean-field games using Γ-convergence. Our techniques are based on the observation that an important class of mean-field games can be viewed as the Euler-Lagrange equation of a suitable functional. Therefore, using a scaling argument, one can convert a long-term convergence problem into a Γ-convergence problem. Our results generalize previous results related to long-term convergence for finite state problems. © 2014 Elsevier Inc.

  20. On the convergence of finite state mean-field games through Γ-convergence

    KAUST Repository

    Ferreira, Rita C.

    2014-10-01

    In this study, we consider the long-term convergence (trend toward an equilibrium) of finite state mean-field games using Γ-convergence. Our techniques are based on the observation that an important class of mean-field games can be viewed as the Euler-Lagrange equation of a suitable functional. Therefore, using a scaling argument, one can convert a long-term convergence problem into a Γ-convergence problem. Our results generalize previous results related to long-term convergence for finite state problems. © 2014 Elsevier Inc.

  1. Media Convergence: the Culture Dimensions of Thinking%Media Convergence:the Culture Dimensions of Thinking

    Institute of Scientific and Technical Information of China (English)

    Shen Diao; Lan Ju

    2017-01-01

    In the process of meida Convergence,many researchers paid excessive attention to media technology,industry and management,and ignored the culture dimensions of media convergence.Therefore,to transcend media convergence technology,industrial thinking and more to the particularity attach importance to cultural media,it is a right way to achieve media convergence.But in the context of China's culture,media convergence should value the cultural uniqueness and the imbalance of the realistic problems,to reach innovation and breakthrough.

  2. TESTING STOCK MARKETS’ INTEGRATION FROM CENTRAL AND EASTERN EUROPEAN COUNTRIES WITHIN EURO ZONE

    Directory of Open Access Journals (Sweden)

    Viorica CHIRILA

    2014-10-01

    Full Text Available Stock market integration gives the opportunity of risk diversification on international level. The main effects of this integration are the development of stock markets and economic growth. This paper analyses the integration of stock markets from Central and Eastern Europe using convergence. Beta-convergence gives us information about integration’s speed and sigma-convergence presents information about the degree of integration of stock markets from Central and Eastern Europe on the stock market of Euro Zone.

  3. Neutron gain for converging guide tubes

    International Nuclear Information System (INIS)

    Mildner, D.F.R.

    1982-01-01

    The method of acceptance diagrams is used to obtain analytical expressions for the neutron gain of a one-dimensional converging guide tube. It is found that the results are more easily expressed by analyzing the acceptance diagram at the exit of the funnel. The results are compared with those for the straight guide. When both guides have the same dimensions at the guide exit, the converging guide has higher transmitted intensity but with greater divergence of the beam. This analytical method is useful to assess the performance of a converging guide, though numerical computations may be required for detailed analysis of a guide system. (orig.)

  4. Convergence analysis of canonical genetic algorithms.

    Science.gov (United States)

    Rudolph, G

    1994-01-01

    This paper analyzes the convergence properties of the canonical genetic algorithm (CGA) with mutation, crossover and proportional reproduction applied to static optimization problems. It is proved by means of homogeneous finite Markov chain analysis that a CGA will never converge to the global optimum regardless of the initialization, crossover, operator and objective function. But variants of CGA's that always maintain the best solution in the population, either before or after selection, are shown to converge to the global optimum due to the irreducibility property of the underlying original nonconvergent CGA. These results are discussed with respect to the schema theorem.

  5. Dissolved Carbon Dioxide in Tropical East Atlantic Surface Waters

    NARCIS (Netherlands)

    Bakker, D.C.E.; Baar, H.J.W. de; Jong, E. de

    1999-01-01

    Variability of dissolved inorganic carbon (DIC) and the fugacity of carbon dioxide (fCO2) is discussed for tropical East Atlantic surface waters in October–November 1993 and May–June 1994. High precipitation associated with the Intertropical Convergence Zone, river input and equatorial upwelling

  6. Distribution and provenance of wind-blown SE Pacific surface sediments

    NARCIS (Netherlands)

    Saukel, C.; Lamy, F.; Stuut, J.B.W.; Tiedemann, R.; Vogt, C.

    2011-01-01

    The reconstruction of low-latitude ocean-atmosphere interactions is one of the major issues of (paleo-) environmental studies. The trade winds, extending over 20 degrees to 30 degrees of latitude in both hemispheres, between the subtropical highs and the intertropical convergence zone, are major

  7. Svecofennian orogeny in an evolving convergent margin setting

    Science.gov (United States)

    Korja, Annakaisa

    2015-04-01

    The dominant tectonic mode changes from extension to convergence at around 1.9 Ga in Fennoscandian. The lithological record suggests short lived subduction-related magmatic events followed by deformation and low-pressure high temperature metamorphism. At around 1.8 Ga the subduction systems seem to have stabilized implying continuous supply of oceanic lithosphere. The evolution of the convergent margin is recorded in the rock record and crustal architecture of the long lived Svecofennian orogeny (1.9-1.7 Ga). A closer look at the internal structure of the Svecofennian orogen reveals distinct regional differences. The northern and central parts of the Svecofennian orogen that have been formed during the initial accretionary phase - or compilation of the nucleus - have a thick three-layer crust and with thick mafic lower crust (10-30 km) and block-like internal architecture. Reflection profiles (FIRE1-3) image listric structures flattening on crustal scale décollement zones at the upper-middle crust and middle-upper crust boundaries. The crustal architecture together with large volumes of exposed granitoid rocks suggests spreading of the orogen and the development of an orogenic plateau west of the continental convergence boundary. The architecture is reminiscent of a large hot orogen. Within the western and southwestern part of the Svecofennian orogen (BABEL B, 1, 2, 3&4), which have been envisioned to have formed during continuous subduction phase, the crust is thinner (45-50 km) and it is hosting crustal blocks having one to two crustal layers. Layering is poorly developed in crustal blocks that are found S-SW of NE-dipping mantle reflections previously interpreted as paleo-subduction zones. Within these blocks, the crustal scale reflective structures dip NE (prowedge) or form pop-up wedges (uplifted plug) above the paleo-subduction zones. Crustal blocks with well-developed two-layer crust are located NE of the paleo-subduction zone. The architecture can be

  8. Strategic business transformation through technology convergence

    DEFF Research Database (Denmark)

    Agarwal, Nivedita; Brem, Alexander

    2015-01-01

    -time intelligence. This paper presents the case of General Electric (GE) and studies the various transitional phases and transformation dimensions that GE is experiencing, to manage this technology convergence. The evaluation of GE's experience indicates that convergence-related business transformation is nonlinear......Technology adoption is crucial for an organisation to remain competitive in the marketplace. Traditionally, two technologies - operational technology (OT) and information technology (IT) - have operated independently from one another; however, technological advancements that businesses...... are experiencing have increased the overlap and convergence of these two areas. Industrial organisations are investing heavily in the integration and alignment of these technologies and expect to benefit in several ways from this convergence, such as through increased productivity, reduction in cost, and real...

  9. Convergent Validity of Four Innovativeness Scales.

    Science.gov (United States)

    Goldsmith, Ronald E.

    1986-01-01

    Four scales of innovativeness were administered to two samples of undergraduate students: the Open Processing Scale, Innovativeness Scale, innovation subscale of the Jackson Personality Inventory, and Kirton Adaption-Innovation Inventory. Intercorrelations indicated the scales generally exhibited convergent validity. (GDC)

  10. A class of convergent neural network dynamics

    Science.gov (United States)

    Fiedler, Bernold; Gedeon, Tomáš

    1998-01-01

    We consider a class of systems of differential equations in Rn which exhibits convergent dynamics. We find a Lyapunov function and show that every bounded trajectory converges to the set of equilibria. Our result generalizes the results of Cohen and Grossberg (1983) for convergent neural networks. It replaces the symmetry assumption on the matrix of weights by the assumption on the structure of the connections in the neural network. We prove the convergence result also for a large class of Lotka-Volterra systems. These are naturally defined on the closed positive orthant. We show that there are no heteroclinic cycles on the boundary of the positive orthant for the systems in this class.

  11. Divergence and convergence in nutrition science

    NARCIS (Netherlands)

    Penders, Bart; Spruit, Shannon L.; Sikkema, Jan; Maat, Jan; Schuurbiers, Daan

    2015-01-01

    Nutrigenomics diverged from mainstream nutrition science, ideologically, instrumentally and culturally, due to the establishment of a protective niche. That protection is fading. This article chronicles a case in which convergence between nutrigenomics and nutrition science is pursued. Here we

  12. Advances and Challenges in Convergent Communication Networks

    DEFF Research Database (Denmark)

    Toral-Cruz, Homero; Mihovska, Albena

    2017-01-01

    Welcome to this special issue of Wireless Personal Communications on Advances and Challenges in Convergent Communication Networks. The main purpose of this special issue is to present new progresses and challenges in convergent networks. Communication networks play an important role in our daily...... life because they allow communicating and sharing contents between heterogeneous nodes around the globe. The emergence of multiple network architectures and emerging technologies have resulted in new applications and services over a heterogeneous network. This heterogeneous network has undergone...... significant challenges in recent years, such as the evolution to a converged network with the capability to support multiple services, while maintaining a satisfactory level of QoE/QoS, security, efficiency and trust. The special issue on Advances and Challenges in Convergent Communication Networks...

  13. Testing the Conditional Convergence Hypothesis for Pakistan

    Directory of Open Access Journals (Sweden)

    Sajjad Ahmad Jan (Corresponding Author

    2011-09-01

    Full Text Available This study investigates for the existence or non-existence of conditional convergence across the provinces of Pakistan. The annual output data from 1973 to 2000 is pooled for the four Pakistani provinces. The cross-sectional specific effects, the time specific effects, the manufacturing output, and the structural variable for aggregate supply or production shocks are used to control the different steady state levels of per capita incomes of thedifferent provinces. The equation for conditional convergence is estimated through generalized least squares (GLS method, after controlling for the different steady states of the provinces. The result shows that the provinces of Pakistan converge to their own respective steady states with a convergence speed of 11% per annum. At the same time manufacturing output is also statistically significant and positively affects the economic growth in the provinces. However the structural variable is not statistically significant.

  14. Convergence of Corporate and Information Security

    OpenAIRE

    Syed; Rahman, M.; Donahue, Shannon E.

    2010-01-01

    As physical and information security boundaries have become increasingly blurry many organizations are experiencing challenges with how to effectively and efficiently manage security within the corporate. There is no current standard or best practice offered by the security community regarding convergence; however many organizations such as the Alliance for Enterprise Security Risk Management (AESRM) offer some excellent suggestions for integrating a converged security program. This paper rep...

  15. Convergence in Global Food Demand and Delivery

    OpenAIRE

    Regmi, Anita; Takeshima, Hiroyuki; Unnevehr, Laurian J.

    2008-01-01

    Using food expenditures and food sales data over 1990-2004, this report examines whether food consumption and delivery trends are converging across 47 high- and middle-income countries. Middle-income countries, such as China and Mexico, appear to be following trends in high-income countries, measured across several dimensions of food system growth and change. Convergence is apparent in most important food expenditure categories and in indicators of food system modernization such as supermarke...

  16. Convergence Science in a Nano World

    OpenAIRE

    Cady, Nathaniel

    2013-01-01

    Convergence is a new paradigm that brings together critical advances in the life sciences, physical sciences and engineering. Going beyond traditional “interdisciplinary” studies, “convergence” describes the culmination of truly integrated research and development, yielding revolutionary advances in both scientific research and new technologies. At its core, nanotechnology embodies these elements of convergence science by bringing together multiple disciplines with the goal of creating innova...

  17. Global Convergence of a Modified LS Method

    Directory of Open Access Journals (Sweden)

    Liu JinKui

    2012-01-01

    Full Text Available The LS method is one of the effective conjugate gradient methods in solving the unconstrained optimization problems. The paper presents a modified LS method on the basis of the famous LS method and proves the strong global convergence for the uniformly convex functions and the global convergence for general functions under the strong Wolfe line search. The numerical experiments show that the modified LS method is very effective in practice.

  18. International Convergence on Geoscience Cyberinfrastructure

    Science.gov (United States)

    Allison, M. L.; Atkinson, R.; Arctur, D. K.; Cox, S.; Jackson, I.; Nativi, S.; Wyborn, L. A.

    2012-04-01

    There is growing international consensus on addressing the challenges to cyber(e)-infrastructure for the geosciences. These challenges include: Creating common standards and protocols; Engaging the vast number of distributed data resources; Establishing practices for recognition of and respect for intellectual property; Developing simple data and resource discovery and access systems; Building mechanisms to encourage development of web service tools and workflows for data analysis; Brokering the diverse disciplinary service buses; Creating sustainable business models for maintenance and evolution of information resources; Integrating the data management life-cycle into the practice of science. Efforts around the world are converging towards de facto creation of an integrated global digital data network for the geosciences based on common standards and protocols for data discovery and access, and a shared vision of distributed, web-based, open source interoperable data access and integration. Commonalities include use of Open Geospatial Consortium (OGC) and ISO specifications and standardized data interchange mechanisms. For multidisciplinarity, mediation, adaptation, and profiling services have been successfully introduced to leverage the geosciences standards which are commonly used by the different geoscience communities -introducing a brokering approach which extends the basic SOA archetype. Principal challenges are less technical than cultural, social, and organizational. Before we can make data interoperable, we must make people interoperable. These challenges are being met by increased coordination of development activities (technical, organizational, social) among leaders and practitioners in national and international efforts across the geosciences to foster commonalities across disparate networks. In doing so, we will 1) leverage and share resources, and developments, 2) facilitate and enhance emerging technical and structural advances, 3) promote

  19. Inversion of convergent-beam electron diffraction patterns

    International Nuclear Information System (INIS)

    Bird, D.M.; Saunders, M.

    1992-01-01

    The problem of recovering the structure factors that contribute to a zone-axis convergent-beam diffraction pattern is discussed. It is shown that an automated matching procedure that minimizes the sum-of-squares difference between experimental and simulated patterns is effective whether one is refining accurate structure factors in a known crystal or attempting ab initio structure determination. The details of the minimization method are analysed and it is shown that a quasi-Newton method that uses analytically derived gradients is particulary effective when several structure factors are varied. The inversion method for ab initio structure determination is tested on the [110] axis of GaP, using simulated patterns as ideal 'experimental' data. (orig.)

  20. ANALYSIS OF CONVERGENCE WITHIN THE EUROPEAN UNION SIGMA AND BETA CONVERGENCE

    Directory of Open Access Journals (Sweden)

    Begu Liviu-Stelian

    2010-12-01

    Full Text Available Real convergence study began with the development of neoclassical models of growth and especially with the passage of econometric applications of these models. In this paper we present applications of indicators and patterns of convergence on the example of European Union member countries and some current economic impact assessments on European convergence process. This analysis is based on the estimated a- and b convergence and on Markov chains. The study deals with the economic convergence of the European countries and especially the convergence of the EU countries, including Romania. In the end of the study presents several economic scenarios for a faster and easier exit from the current crisis in Romania.

  1. [The detector, the command neuron and plastic convergence].

    Science.gov (United States)

    Sokolov, E N

    1977-01-01

    The paper deals with the structure of detectors, the function of commanding neurones and the problem of relationship between detectors and commanding neurons. An example of hierarchial organization of detectors is provided by the colour analyser in which a layer of receptors, a layer of opponent neurones and a layer of colour-selective detectors are singled out. The colour detector is selectively sensitive to a certain combination of excitations at the input. If the detector is selectively activated by a certain combination of excitations at the input, the selective activation of the commanding neurone through a pool of motoneurones brings about a reaction at the output, specific in its organization. The reflexogenic zone of the reaction is determined by the detectors which converge on the commanding neurone controlling the given reaction. The plasticity of the reaction results from a plastic convergence of the detectors on the commanding neurone which controls the reaction. This comprises selective switching off the detectors from the commanding neurone (habituation) and connecting the detectors to the commanding neurone (facilitation).

  2. Possibilities for global governance of converging technologies

    Science.gov (United States)

    Roco, Mihail C.

    2008-01-01

    The convergence of nanotechnology, modern biology, the digital revolution and cognitive sciences will bring about tremendous improvements in transformative tools, generate new products and services, enable opportunities to meet and enhance human potential and social achievements, and in time reshape societal relationships. This paper focuses on the progress made in governance of such converging, emerging technologies and suggests possibilities for a global approach. Specifically, this paper suggests creating a multidisciplinary forum or a consultative coordinating group with members from various countries to address globally governance of converging, emerging technologies. The proposed framework for governance of converging technologies calls for four key functions: supporting the transformative impact of the new technologies; advancing responsible development that includes health, safety and ethical concerns; encouraging national and global partnerships; and establishing commitments to long-term planning and investments centered on human development. Principles of good governance guiding these functions include participation of all those who are forging or affected by the new technologies, transparency of governance strategies, responsibility of each participating stakeholder, and effective strategic planning. Introduction and management of converging technologies must be done with respect for immediate concerns, such as privacy, access to medical advancements, and potential human health effects. At the same time, introduction and management should also be done with respect for longer-term concerns, such as preserving human integrity, dignity and welfare. The suggested governance functions apply to four levels of governance: (a) adapting existing regulations and organizations; (b) establishing new programs, regulations and organizations specifically to handle converging technologies; (c) building capacity for addressing these issues into national policies and

  3. Possibilities for global governance of converging technologies

    International Nuclear Information System (INIS)

    Roco, Mihail C.

    2008-01-01

    The convergence of nanotechnology, modern biology, the digital revolution and cognitive sciences will bring about tremendous improvements in transformative tools, generate new products and services, enable opportunities to meet and enhance human potential and social achievements, and in time reshape societal relationships. This paper focuses on the progress made in governance of such converging, emerging technologies and suggests possibilities for a global approach. Specifically, this paper suggests creating a multidisciplinary forum or a consultative coordinating group with members from various countries to address globally governance of converging, emerging technologies. The proposed framework for governance of converging technologies calls for four key functions: supporting the transformative impact of the new technologies; advancing responsible development that includes health, safety and ethical concerns; encouraging national and global partnerships; and establishing commitments to long-term planning and investments centered on human development. Principles of good governance guiding these functions include participation of all those who are forging or affected by the new technologies, transparency of governance strategies, responsibility of each participating stakeholder, and effective strategic planning. Introduction and management of converging technologies must be done with respect for immediate concerns, such as privacy, access to medical advancements, and potential human health effects. At the same time, introduction and management should also be done with respect for longer-term concerns, such as preserving human integrity, dignity and welfare. The suggested governance functions apply to four levels of governance: (a) adapting existing regulations and organizations; (b) establishing new programs, regulations and organizations specifically to handle converging technologies; (c) building capacity for addressing these issues into national policies and

  4. Possibilities for global governance of converging technologies

    Energy Technology Data Exchange (ETDEWEB)

    Roco, Mihail C. [National Science Foundation (NSF) (United States)], E-mail: mroco@nsf.gov

    2008-01-15

    The convergence of nanotechnology, modern biology, the digital revolution and cognitive sciences will bring about tremendous improvements in transformative tools, generate new products and services, enable opportunities to meet and enhance human potential and social achievements, and in time reshape societal relationships. This paper focuses on the progress made in governance of such converging, emerging technologies and suggests possibilities for a global approach. Specifically, this paper suggests creating a multidisciplinary forum or a consultative coordinating group with members from various countries to address globally governance of converging, emerging technologies. The proposed framework for governance of converging technologies calls for four key functions: supporting the transformative impact of the new technologies; advancing responsible development that includes health, safety and ethical concerns; encouraging national and global partnerships; and establishing commitments to long-term planning and investments centered on human development. Principles of good governance guiding these functions include participation of all those who are forging or affected by the new technologies, transparency of governance strategies, responsibility of each participating stakeholder, and effective strategic planning. Introduction and management of converging technologies must be done with respect for immediate concerns, such as privacy, access to medical advancements, and potential human health effects. At the same time, introduction and management should also be done with respect for longer-term concerns, such as preserving human integrity, dignity and welfare. The suggested governance functions apply to four levels of governance: (a) adapting existing regulations and organizations; (b) establishing new programs, regulations and organizations specifically to handle converging technologies; (c) building capacity for addressing these issues into national policies and

  5. Zone separator for multiple zone vessels

    Science.gov (United States)

    Jones, John B.

    1983-02-01

    A solids-gas contact vessel, having two vertically disposed distinct reaction zones, includes a dynamic seal passing solids from an upper to a lower zone and maintaining a gas seal against the transfer of the separate treating gases from one zone to the other, and including a stream of sealing fluid at the seal.

  6. Advancing Understanding of Earthquakes by Drilling an Eroding Convergent Margin

    Science.gov (United States)

    von Huene, R.; Vannucchi, P.; Ranero, C. R.

    2010-12-01

    A program of IODP with great societal relevance is sampling and instrumenting the seismogenic zone. The zone generates great earthquakes that trigger tsunamis, and submarine slides thereby endangering coastal communities containing over sixty percent of the earth’s population. To asses and mitigate this endangerment it is urgent to advance understanding of fault dynamics that allows more timely anticipation of hazardous seismicity. Seismogenesis on accreting and eroding convergent plate boundaries apparently differ because of dissimilar materials along the interplate fault. As the history of instrumentally recorded earthquakes expands the difference becomes clearer. The more homogeneous clay, silt and sand subducted at accreting margins is associated with great earthquakes (M 9) whereas the fragmented upper plate rock that can dominate subducted material along an eroding margin plate interface is associated with many tsunamigenic earthquakes (Bilek, 2010). Few areas have been identified where the seismogenic zone can be reached with scientific drilling. In IODP accreting margins are studied on the NanTroSeize drill transect off Japan where the ultimate drilling of the seismogenic interface may occur by the end of IODP. The eroding Costa Rica margin will be studied in CRISP where a drill program will begin in 2011. The Costa Rican geophysical site survey will be complete with acquisition and processing of 3D seismic data in 2011 but the entire drilling will not be accomplished in IODP. It is appropriate that the accreting margin study be accomplished soon considering the indications of a pending great earthquake that will affect a country that has devoted enormous resources to IODP. However, understanding the erosional end-member is scientifically as important to an understanding of fault mechanics. Transoceanic tsunamis affect the entire Pacific rim where most subduction zones are eroding margins. The Costa Rican subduction zone is less complex operationally and

  7. Time-Spatial Convergence of Air Pollution and Regional Economic Growth in China

    Directory of Open Access Journals (Sweden)

    Zhengning Pu

    2017-07-01

    Full Text Available The haze pollution caused by fine particulate matter (PM 2.5 emissions has become one of the most crucial topics of sustainable environmental governance in China. Using the average concentration of PM 2.5 in China’s key cities from 2000 to 2012, as measured by aerosol optical depth, this study tested the time-spatial convergence of fine particulate matter pollution in China. The results show that there is a trend of absolute convergence between timespan and China’s PM 2.5 emissions. At the same time, in the geographic areas divided by the east, middle and west zones, there is a significant difference in the convergence rate of PM 2.5. The growth rate of PM 2.5 in the middle and west zones is significantly higher than that of the east zone. The correlation test between regional economic growth and PM 2.5 emissions suggest a significant positive N-type Environmental Kuznets Curve (EKC after considering spatial lag and spatial error effect.

  8. Gene Acquisition Convergence between Entomopoxviruses and Baculoviruses

    Directory of Open Access Journals (Sweden)

    Julien Thézé

    2015-04-01

    Full Text Available Organisms from diverse phylogenetic origins can thrive within the same ecological niches. They might be induced to evolve convergent adaptations in response to a similar landscape of selective pressures. Their genomes should bear the signature of this process. The study of unrelated virus lineages infecting the same host panels guarantees a clear identification of phyletically independent convergent adaptation. Here, we investigate the evolutionary history of genes in the accessory genome shared by unrelated insect large dsDNA viruses: the entomopoxviruses (EPVs, Poxviridae and the baculoviruses (BVs. EPVs and BVs have overlapping ecological niches and have independently evolved similar infection processes. They are, in theory, subjected to the same selective pressures from their host’s immune responses. Their accessory genomes might, therefore, bear analogous genomic signatures of convergent adaption and could point out key genomic mechanisms of adaptation hitherto undetected in viruses. We uncovered 32 homologous, yet independent acquisitions of genes originating from insect hosts, different eukaryotes, bacteria and viruses. We showed different evolutionary levels of gene acquisition convergence in these viruses, underlining a continuous evolutionary process. We found both recent and ancient gene acquisitions possibly involved to the adaptation to both specific and distantly related hosts. Multidirectional and multipartite gene exchange networks appear to constantly drive exogenous gene assimilations, bringing key adaptive innovations and shaping the life histories of large DNA viruses. This evolutionary process might lead to genome level adaptive convergence.

  9. Log-binomial models: exploring failed convergence.

    Science.gov (United States)

    Williamson, Tyler; Eliasziw, Misha; Fick, Gordon Hilton

    2013-12-13

    Relative risk is a summary metric that is commonly used in epidemiological investigations. Increasingly, epidemiologists are using log-binomial models to study the impact of a set of predictor variables on a single binary outcome, as they naturally offer relative risks. However, standard statistical software may report failed convergence when attempting to fit log-binomial models in certain settings. The methods that have been proposed in the literature for dealing with failed convergence use approximate solutions to avoid the issue. This research looks directly at the log-likelihood function for the simplest log-binomial model where failed convergence has been observed, a model with a single linear predictor with three levels. The possible causes of failed convergence are explored and potential solutions are presented for some cases. Among the principal causes is a failure of the fitting algorithm to converge despite the log-likelihood function having a single finite maximum. Despite these limitations, log-binomial models are a viable option for epidemiologists wishing to describe the relationship between a set of predictors and a binary outcome where relative risk is the desired summary measure. Epidemiologists are encouraged to continue to use log-binomial models and advocate for improvements to the fitting algorithms to promote the widespread use of log-binomial models.

  10. Noise can speed convergence in Markov chains.

    Science.gov (United States)

    Franzke, Brandon; Kosko, Bart

    2011-10-01

    A new theorem shows that noise can speed convergence to equilibrium in discrete finite-state Markov chains. The noise applies to the state density and helps the Markov chain explore improbable regions of the state space. The theorem ensures that a stochastic-resonance noise benefit exists for states that obey a vector-norm inequality. Such noise leads to faster convergence because the noise reduces the norm components. A corollary shows that a noise benefit still occurs if the system states obey an alternate norm inequality. This leads to a noise-benefit algorithm that requires knowledge of the steady state. An alternative blind algorithm uses only past state information to achieve a weaker noise benefit. Simulations illustrate the predicted noise benefits in three well-known Markov models. The first model is a two-parameter Ehrenfest diffusion model that shows how noise benefits can occur in the class of birth-death processes. The second model is a Wright-Fisher model of genotype drift in population genetics. The third model is a chemical reaction network of zeolite crystallization. A fourth simulation shows a convergence rate increase of 64% for states that satisfy the theorem and an increase of 53% for states that satisfy the corollary. A final simulation shows that even suboptimal noise can speed convergence if the noise applies over successive time cycles. Noise benefits tend to be sharpest in Markov models that do not converge quickly and that do not have strong absorbing states.

  11. Sectoral Energy, and Labour, Productivity Convergence

    International Nuclear Information System (INIS)

    Mulder, P.; De Groot, H.L.F.

    2007-01-01

    This paper empirically investigates the development of cross-country differences in energy- and labour productivity. The analysis is performed at a detailed sectoral level for 14 OECD countries, covering the period 1970-1997. A ρ-convergence analysis reveals that the development over time of the cross-country variation in productivity performance differs across sectors as well as across different levels of aggregation. Both patterns of convergence as well as divergence are found. Cross-country variation of productivity levels is typically larger for energy than for labour. A β-convergence analysis provides support for the hypothesis that in most sectors lagging countries tend to catch up with technological leaders, in particular in terms of energy productivity. Moreover, the results show that convergence is conditional, meaning that productivity levels converge to country-specific steady states. Energy prices and wages are shown to positively affect energy- and labour-productivity growth, respectively. We also find evidence for the importance of economies of scale, whereas the investment share, openness and specialization play only a modest role in explaining cross-country variation in energy- and labour-productivity growth

  12. Convergent dynamics for multistable delayed neural networks

    International Nuclear Information System (INIS)

    Shih, Chih-Wen; Tseng, Jui-Pin

    2008-01-01

    This investigation aims at developing a methodology to establish convergence of dynamics for delayed neural network systems with multiple stable equilibria. The present approach is general and can be applied to several network models. We take the Hopfield-type neural networks with both instantaneous and delayed feedbacks to illustrate the idea. We shall construct the complete dynamical scenario which comprises exactly 2 n stable equilibria and exactly (3 n − 2 n ) unstable equilibria for the n-neuron network. In addition, it is shown that every solution of the system converges to one of the equilibria as time tends to infinity. The approach is based on employing the geometrical structure of the network system. Positively invariant sets and componentwise dynamical properties are derived under the geometrical configuration. An iteration scheme is subsequently designed to confirm the convergence of dynamics for the system. Two examples with numerical simulations are arranged to illustrate the present theory

  13. Well-Tempered Metadynamics Converges Asymptotically

    Science.gov (United States)

    Dama, James F.; Parrinello, Michele; Voth, Gregory A.

    2014-06-01

    Metadynamics is a versatile and capable enhanced sampling method for the computational study of soft matter materials and biomolecular systems. However, over a decade of application and several attempts to give this adaptive umbrella sampling method a firm theoretical grounding prove that a rigorous convergence analysis is elusive. This Letter describes such an analysis, demonstrating that well-tempered metadynamics converges to the final state it was designed to reach and, therefore, that the simple formulas currently used to interpret the final converged state of tempered metadynamics are correct and exact. The results do not rely on any assumption that the collective variable dynamics are effectively Brownian or any idealizations of the hill deposition function; instead, they suggest new, more permissive criteria for the method to be well behaved. The results apply to tempered metadynamics with or without adaptive Gaussians or boundary corrections and whether the bias is stored approximately on a grid or exactly.

  14. Filamentation of a converging heavy ion beam

    International Nuclear Information System (INIS)

    Lee, E.P.; Buchanan, H.L.; Rosenbluth, M.N.

    1980-01-01

    A major concern in the use of heavy ion beams as igniters in pellet fusion systems is the vulnerability of the beam to the transverse flamentation instability. The undesirable consequence of this mode is the transverse heating of the beam to the extent that convergence on the pellet becomes impossible. This work considers the case of a beam injected into a gas filled reactor vessel, where finite pulse length and propagation distance play an important role in limiting growth. Two geometries are analyzed: a nonconverging case where the radius at injection is nearly equal to the desired radius at the pellet, and a converging case in which the injection radius is large and the beam is pre-focused to converge at the target. It is found that a cold beam will be severely disrupted if the product of the magnetic plasma frequency and the propagation distance is much larger than unity

  15. Multicloud: Multigrid convergence with a meshless operator

    International Nuclear Information System (INIS)

    Katz, Aaron; Jameson, Antony

    2009-01-01

    The primary objective of this work is to develop and test a new convergence acceleration technique we call multicloud. Multicloud is well-founded in the mathematical basis of multigrid, but relies on a meshless operator on coarse levels. The meshless operator enables extremely simple and automatic coarsening procedures for arbitrary meshes using arbitrary fine level discretization schemes. The performance of multicloud is compared with established multigrid techniques for structured and unstructured meshes for the Euler equations on two-dimensional test cases. Results indicate comparable convergence rates per unit work for multicloud and multigrid. However, because of its mesh and scheme transparency, multicloud may be applied to a wide array of problems with no modification of fine level schemes as is often required with agglomeration techniques. The implication is that multicloud can be implemented in a completely modular fashion, allowing researchers to develop fine level algorithms independent of the convergence accelerator for complex three-dimensional problems.

  16. Plurality or convergence in sustainability reporting standards?

    Directory of Open Access Journals (Sweden)

    Nadia Albu

    2013-11-01

    Full Text Available Over the last years an increasing number of companies issued Corporate Social Responsibility (CSR or Sustainability Reports to complement their traditional financial reporting. Companies use various sustainability reporting standards or develop their own reporting frameworks starting from the existing ones. This variation of practices pointed out by empirical research raises questions about the quality and comparability of sustainability reporting, its role in the sustainable development, and also about the suitability of accepting the plurality of reporting frameworks or the need for convergence. This study aims to investigate the issues of plurality and convergence in sustainability reporting standards, by mobilizing the discourses on regulation and the case of a group of companies in the IT industry in order to shed some light on the current challenges in this area. We frame a discussion on the opportunities and pitfalls of convergence in sustainability reporting regulations and contribute to a better understanding of this issue by academics, preparers, users and standard setters

  17. International Accounting Convergences Related to EU Admitance

    Directory of Open Access Journals (Sweden)

    Niculae Feleaga

    2006-05-01

    Full Text Available Starting from January 1, 2005, member countries of the European Union began the obligatory or optional application of the international standards IAS/IFRS for consolidated accounts, what means a revolution in financial reporting of the enterprises. In regards to the individual accounts (generally based on the national book-keeping standards these will converge gradually to referential international book-keeper on short and medium term. At the world level the process which dominates the accounting systems is the convergence between american and international reference system, followed immediatly more or less by the convergence between national accounting systems and the international one. Where Romania and its specialists are situated confronting this process? A reflection subject which finalises this article.

  18. Science and technology convergence: with emphasis for nanotechnology-inspired convergence

    International Nuclear Information System (INIS)

    Bainbridge, William S.; Roco, Mihail C.

    2016-01-01

    Convergence offers a new universe of discovery, innovation, and application opportunities through specific theories, principles, and methods to be implemented in research, education, production, and other societal activities. Using a holistic approach with shared goals, convergence seeks to transcend existing human limitations to achieve improved conditions for work, learning, aging, physical, and cognitive wellness. This paper outlines ten key theories that offer complementary perspectives on this complex dynamic. Principles and methods are proposed to facilitate and enhance science and technology convergence. Several convergence success stories in the first part of the 21st century—including nanotechnology and other emerging technologies—are discussed in parallel with case studies focused on the future. The formulation of relevant theories, principles, and methods aims at establishing the convergence science.

  19. Science and technology convergence: with emphasis for nanotechnology-inspired convergence

    Energy Technology Data Exchange (ETDEWEB)

    Bainbridge, William S.; Roco, Mihail C., E-mail: mroco@nsf.gov [National Science Foundation (United States)

    2016-07-15

    Convergence offers a new universe of discovery, innovation, and application opportunities through specific theories, principles, and methods to be implemented in research, education, production, and other societal activities. Using a holistic approach with shared goals, convergence seeks to transcend existing human limitations to achieve improved conditions for work, learning, aging, physical, and cognitive wellness. This paper outlines ten key theories that offer complementary perspectives on this complex dynamic. Principles and methods are proposed to facilitate and enhance science and technology convergence. Several convergence success stories in the first part of the 21st century—including nanotechnology and other emerging technologies—are discussed in parallel with case studies focused on the future. The formulation of relevant theories, principles, and methods aims at establishing the convergence science.

  20. Convergence of the Distorted Wave Born series

    International Nuclear Information System (INIS)

    MacMillan, D.S.

    1981-01-01

    The aim of this thesis is to begin to understand the idea of reaction mechanisms in nonrelativistic scattering systems. If we have a complete reaction theory of a particular scattering system, then we claim that the theory itself must contain information about important reaction mechanisms in the system. This information can be used to decide what reaction mechanisms should be included in an approximate calculation. To investigate this claim, we studied several solvable models. The primary concept employed in studying our models is the convergence of the multistep series generated by iterating the corresponding scattering integral equation. We known that the eigenvalues of the kernel of the Lippmann-Schwinger equation for potential scattering determine the rate of convergence of the Born series. The Born series will converge only if these eigenvalues all life within the unit circle. We extend these results to a study of the distorted wave Born series for inelastic scattering. The convergence criterion tells us when approximations are valid. We learn how the convergence of the distorted wave series depends upon energy, coupling constants, angular momentum, and angular momentum transfer. In one of our models, we look at several possible distorting potentials to see which one gives the best convergence. We have also applied our results to several actual DWBA or coupled channel calculations in the literature. In addition to the study of models of two-body scattering systems, we have considered the case of rearrangement scattering. We have discussed the formulation of (N greater than or equal to 3)-body distorted wave equations in which the interior dynamics have been redistributed by introducing compact N-body distortion potentials

  1. Specialisation and Convergence in European Regions

    Directory of Open Access Journals (Sweden)

    Enrico Marelli

    2007-09-01

    Full Text Available The purpose of this paper was to analyze specialization and convergence of European countries and regions, within the framework of integration in the EU. This is important not only for long-term real convergence processes, but also for a proper functioning of the monetary union (in the line of research on the OCA's criteria, asymmetry of shocks and synchronization of business cycles. The position of new member states is particularly delicate, also considering the forthcoming adoption of the euro by some of them. As indicated by the EU Treaty, economic growth should be balanced with economic and social cohesion that includes a careful consideration of regional disparities. Our empirical investigation focuses on the regions of EU25, further broken up into other relevant groupings (EU15, EMU, and the new members' EU10 group, over the period from 1980 (or 1990 for EU10 to 2005. This paper considers a rather fine regional disaggregation (NUTS-2 level, counting 250 regions. The analysis of different indices of specialisation point to a prevalent increase of homogeneity of sector structures across European regions, although in some cases (especially in the industrial sector and in some services specialisation has increased. For convergence, a sigma convergence's analysis confirms a reduction of disparities, both at a country and regional level. However, a trade-off between fast national growth and internal distribution has emerged in the early stages of development, as in the case of new members. Moreover, beta convergence has also been established - regarding per capita income, employment and productivity - for almost all territorial aggregates (excluding the new members since 1999. The addition of structural variables, following a beta-conditional approach, indicates a positive role for services and a negative impact of agriculture. Finally, some preliminary results have been obtained by the innovative inclusion of specialisation indices within

  2. GLOBAL CONVERGENCE FOR THE XOR BOOLEAN NETWORKS

    OpenAIRE

    Ho, Juei-Ling

    2009-01-01

    Shih and Ho have proved a global convergent theorem for boolean network: if a map from $\\{0,1\\}^{n}$ to itself defines a boolean network has the conditions: (1) each column of the discrete Jacobian matrix of each element of $\\{0,1\\}^{n}$ is either a unit vector or a zero vector; (2) all the boolean eigenvalues of the discrete Jacobian matrix of this map evaluated at each element of $\\{0,1\\}^{n}$ are zero, then it has a unique fixed point and this boolean network is global convergent to the fi...

  3. Convergence of Hybrid Space Mapping Algorithms

    DEFF Research Database (Denmark)

    Madsen, Kaj; Søndergaard, Jacob

    2004-01-01

    may be poor, or the method may even fail to converge to a stationary point. We consider a convex combination of the space mapping technique with a classical optimization technique. The function to be optimized has the form \\$H \\$\\backslash\\$circ f\\$ where \\$H: \\$\\backslash\\$dR\\^m \\$\\backslash......\\$mapsto \\$\\backslash\\$dR\\$ is convex and \\$f: \\$\\backslash\\$dR\\^n \\$\\backslash\\$mapsto \\$\\backslash\\$dR\\^m\\$ is smooth. Experience indicates that the combined method maintains the initial efficiency of the space mapping technique. We prove that the global convergence property of the classical technique is also...

  4. Lacunary ideal convergence of multiple sequences

    Directory of Open Access Journals (Sweden)

    Bipan Hazarika

    2016-01-01

    Full Text Available An ideal I is a family of subsets of N×N which is closed under taking finite unions and subsets of its elements. In this article, the concept of lacunary ideal convergence of double sequences has been introduced. Also the relation between lacunary ideal convergent and lacunary Cauchy double sequences has been established. Furthermore, the notions of lacunary ideal limit point and lacunary ideal cluster points have been introduced and find the relation between these two notions. Finally, we have studied the properties such as solidity, monotonic.

  5. Nanotechnologies, technologies converging and potential biomedical applications

    International Nuclear Information System (INIS)

    Capuano, Vincenzo

    2005-01-01

    The applications of nanotechnology to biology and medicine appear really promising far diagnostics, for various therapeutic approaches and in medical instrumentations. The growing synergism among nanotechnology, biotechnology, information technology and cognitive sciences, their convergence (NBIC) from the nano scale, could involve on next decades great changes in medicine, from a reactive to a predictive and preventive approach. It is expected that NBIC converging technologies could achieve tremendous improvements in human abilities and enhance societal achievements. It appears therefore necessary a careful assessment of related social and ethical implications, in the framework of a constant dialogue between science and society [it

  6. Radiation protection zoning

    International Nuclear Information System (INIS)

    2015-01-01

    Radiation being not visible, the zoning of an area containing radioactive sources is important in terms of safety. Concerning radiation protection, 2 work zones are defined by regulations: the monitored zone and the controlled zone. The ministerial order of 15 may 2006 settles the frontier between the 2 zones in terms of radiation dose rates, the rules for access and the safety standards in both zones. Radioprotection rules and the name of the person responsible for radiation protection must be displayed. The frontier between the 2 zones must be materialized and marked with adequate equipment (specific danger signs and tapes). Both zones are submitted to selective entrance, the access for the controlled zone is limited because of the radiation risk and of the necessity of confining radioactive contamination while the limitation of the access to the monitored zone is due to radiation risk only. (A.C.)

  7. Professional Communication and Translation in Convergence

    DEFF Research Database (Denmark)

    Gnecci, Marusca; Maylath, Bruce; Mousten, Birthe

    2008-01-01

    As translation of technical documents becomes commonplace, and as translation becomes more automated, the roles of translator and technical communicator appear to be converging. This paper examines the trend revealed from recent surveys, and it suggests further research to determine if the trend...... is likely to continue. The  paper also provides recommendations for academic programs interested in adjusting to the trend....

  8. Strong Ideal Convergence in Probabilistic Metric Spaces

    Indian Academy of Sciences (India)

    In the present paper we introduce the concepts of strongly ideal convergent sequence and strong ideal Cauchy sequence in a probabilistic metric (PM) space endowed with the strong topology, and establish some basic facts. Next, we define the strong ideal limit points and the strong ideal cluster points of a sequence in this ...

  9. Convergent acquisition of antibiotic resistance determinants ...

    African Journals Online (AJOL)

    Convergent acquisition of antibiotic resistance determinants amongst the Enterobacteriaceae isolates of the Mhlathuze River, KwaZulu-Natal (RSA) ... The possibility of transmission of resistant genes between bacteria (especially pathogenic) which invade human and animal populations within this river poses a health risk ...

  10. Culture and Social Psychology: Converging Perspectives

    Science.gov (United States)

    Dimaggio, Paul; Markus, Hazel Rose

    2010-01-01

    Views of culture in psychology and sociology have converged markedly in the past two decades. Both have rejected what Adams and Markus (2004) refer to as the "entity" conception of culture--the view that culture is coherent, stable, and located in the heads of collectivities' members--in favor of more supple and dynamic constructs. Culture, in…

  11. Evolutionary convergence and biologically embodied cognition

    NARCIS (Netherlands)

    Keijzer, Franciscus

    2017-01-01

    The study of evolutionary patterns of cognitive convergence would be greatly helped by a clear demarcation of cognition. Cognition is often used as an equivalent of mind, making it difficult to pin down empirically or to apply it confidently beyond the human condition. Recent developments in

  12. Convergence properties of the effective interaction

    International Nuclear Information System (INIS)

    Ellis, P.J.; Engeland, T.; Hjorth-Jensen, M.; Holt, A.; Osnes, E.

    1994-01-01

    The convergence properties of two perturbative schemes to sum the so-called folded diagrams are critically reviewed in this work, with an emphasis on the intruder state problem. The methods we study are the approaches of Kuo and co-workers and Lee and Suzuki. The suitability of the two schemes for shell-model calculations is discussed. ((orig.))

  13. RNA polymerase II collision interrupts convergent transcription

    DEFF Research Database (Denmark)

    Hobson, David J; Wei, Wu; Steinmetz, Lars M

    2012-01-01

    Antisense noncoding transcripts, genes-within-genes, and convergent gene pairs are prevalent among eukaryotes. The existence of such transcription units raises the question of what happens when RNA polymerase II (RNAPII) molecules collide head-to-head. Here we use a combination of biochemical...

  14. Professional Communication and Translation in Convergence

    DEFF Research Database (Denmark)

    Gnecci, Marusca; Maylath, Bruce; Mousten, Birthe

    2008-01-01

    As translation of technical documents becomes commonplace, and as translation becomes more automated, the roles of translator and technical communicator appear to be converging. This paper examines the trend revealed from recent surveys, and it suggests further research to determine if the trend...

  15. Strong Statistical Convergence in Probabilistic Metric Spaces

    OpenAIRE

    Şençimen, Celaleddin; Pehlivan, Serpil

    2008-01-01

    In this article, we introduce the concepts of strongly statistically convergent sequence and strong statistically Cauchy sequence in a probabilistic metric (PM) space endowed with the strong topology, and establish some basic facts. Next, we define the strong statistical limit points and the strong statistical cluster points of a sequence in this space and investigate the relations between these concepts.

  16. Convergence properties of the effective interaction

    International Nuclear Information System (INIS)

    Ellis, P.J.; Engeland, T.; Hjorth-Jensen, M.; Holt, A.; Osnes, E.

    1993-10-01

    The convergence properties of two perturbative schemes to sum the so called folded diagrams are critically reviewed with an emphasis on the intruder state problem. The methods studied are the approaches of Kuo and co-workers and Lee and Suzuki. The suitability of the two schemes for shell-model calculations is discussed. 11 refs., 3 figs., 1 tab

  17. Another Perspective: A Response to "Toward Convergence"

    Science.gov (United States)

    Regelski, Thomas A.

    2013-01-01

    This response by Thomas A. Regelski was solicited to complement the lead article in this issue, "Toward Convergence: Adapting Music Education to Contemporary Society and Participatory Culture" by Evan S. Tobias. The author notes that many interesting and vital questions and alternatives that are often studiously ignored, overlooked, or taken for…

  18. Convergence Science in a Nano World

    Science.gov (United States)

    Cady, Nathaniel

    2013-01-01

    Convergence is a new paradigm that brings together critical advances in the life sciences, physical sciences and engineering. Going beyond traditional “interdisciplinary” studies, “convergence” describes the culmination of truly integrated research and development, yielding revolutionary advances in both scientific research and new technologies. At its core, nanotechnology embodies these elements of convergence science by bringing together multiple disciplines with the goal of creating innovative and groundbreaking technologies. In the biological and biomedical sciences, nanotechnology research has resulted in dramatic improvements in sensors, diagnostics, imaging, and even therapeutics. In particular, there is a current push to examine the interface between the biological world and micro/nano-scale systems. For example, my laboratory is developing novel strategies for spatial patterning of biomolecules, electrical and optical biosensing, nanomaterial delivery systems, cellular patterning techniques, and the study of cellular interactions with nano-structured surfaces. In this seminar, I will give examples of how convergent research is being applied to three major areas of biological research &endash; cancer diagnostics, microbiology, and DNA-based biosensing. These topics will be presented as case studies, showing the benefits (and challenges) of multi-disciplinary, convergent research and development.

  19. Summability of alterations of convergent series

    Directory of Open Access Journals (Sweden)

    T. A. Keagy

    1981-01-01

    Full Text Available The effect of splitting, rearrangement, and grouping series alterations on the summability of a convergent series by ℓ−ℓ and cs−cs matrix methods is studied. Conditions are determined that guarantee the existence of alterations that are transformed into divergent series and into series with preassigned sums.

  20. International convergence of capital market interest rates.

    NARCIS (Netherlands)

    Fase, M.M.G.; Vlaar, P.J.G.

    1997-01-01

    This article investigates the extent of capital market interest rate convergence among six EU countries on the one hand, and a group of four countries with floating exchange rates - US, Germany, Japan and Switzerland - on the other. We conclude that interest rate changes within the EU have been and

  1. World health inequality: convergence, divergence, and development.

    Science.gov (United States)

    Clark, Rob

    2011-02-01

    Recent studies characterize the last half of the twentieth century as an era of cross-national health convergence, with some attributing welfare gains in the developing world to economic growth. In this study, I examine the extent to which welfare outcomes have actually converged and the extent to which economic development is responsible for the observed trends. Drawing from estimates covering 195 nations during the 1955-2005 period, I find that life expectancy averages converged during this time, but that infant mortality rates continuously diverged. I develop a narrative that implicates economic development in these contrasting trends, suggesting that health outcomes follow a "welfare Kuznets curve." Among poor countries, economic development improves life expectancy more than it reduces infant mortality, whereas the situation is reversed among wealthier nations. In this way, development has contributed to both convergence in life expectancy and divergence in infant mortality. Drawing from 674 observations across 163 countries during the 1980-2005 period, I find that the positive effect of GDP PC on life expectancy attenuates at higher levels of development, while the negative effect of GDP PC on infant mortality grows stronger. Copyright © 2010 Elsevier Ltd. All rights reserved.

  2. Intermediates and Generic Convergence to Equilibria

    DEFF Research Database (Denmark)

    Marcondes de Freitas, Michael; Wiuf, Carsten; Feliu, Elisenda

    2017-01-01

    Known graphical conditions for the generic and global convergence to equilibria of the dynamical system arising from a reaction network are shown to be invariant under the so-called successive removal of intermediates, a systematic procedure to simplify the network, making the graphical conditions...

  3. On Investigating GMRES Convergence using Unitary Matrices

    Czech Academy of Sciences Publication Activity Database

    Duintjer Tebbens, Jurjen; Meurant, G.; Sadok, H.; Strakoš, Z.

    2014-01-01

    Roč. 450, 1 June (2014), s. 83-107 ISSN 0024-3795 Grant - others:GA AV ČR(CZ) M100301201; GA MŠk(CZ) LL1202 Institutional support: RVO:67985807 Keywords : GMRES convergence * unitary matrices * unitary spectra * normal matrices * Krylov residual subspace * Schur parameters Subject RIV: BA - General Mathematics Impact factor: 0.939, year: 2014

  4. Exponential rate of convergence in current reservoirs

    OpenAIRE

    De Masi, Anna; Presutti, Errico; Tsagkarogiannis, Dimitrios; Vares, Maria Eulalia

    2015-01-01

    In this paper, we consider a family of interacting particle systems on $[-N,N]$ that arises as a natural model for current reservoirs and Fick's law. We study the exponential rate of convergence to the stationary measure, which we prove to be of the order $N^{-2}$.

  5. Uniform Statistical Convergence on Time Scales

    Directory of Open Access Journals (Sweden)

    Yavuz Altin

    2014-01-01

    Full Text Available We will introduce the concept of m- and (λ,m-uniform density of a set and m- and (λ,m-uniform statistical convergence on an arbitrary time scale. However, we will define m-uniform Cauchy function on a time scale. Furthermore, some relations about these new notions are also obtained.

  6. Impact of fixed-mobile convergence

    DEFF Research Database (Denmark)

    Pachnicke, Stephan; Andrus, Bogdan-Mihai; Autenrieth, Achim

    2016-01-01

    Fixed-Mobile Convergence (FMC) is a very trendy concept as it promises integration of the previously separated fixed access network and the mobile network. From this novel approach telecommunication operators expect significant cost savings and performance improvements. FMC can be separated...

  7. Converging technologies: shaping the future of medicine

    Directory of Open Access Journals (Sweden)

    Iraj nabipour

    2015-01-01

    Full Text Available The miniaturization and virtualization processes drive converging technologies from interactions between the NBIC (Nano, Bio, Info, and Cogno technologies. The converging technologies stimulate innovation, promote research and development in different fields and produce revolutionary progresses in medicine. These technologies enable us to create contacts between brains and machines, the growth in molecular nanotechnology, the construction of respirocytes, chromallocytes, clottocytes, nanorobotic phagocytes, and nanobots. Nanobots would enter the nucleus of a cell and extract all of the genetic material and replace it with a synthetically produced copy of the original that has been manufactured in a laboratory to contain only non-defective base-pairs. It is predicted that “the regenerative medicine”, as a megatrend, will have an enormous effect on medical technologies and clinical sciences. Regenerative medicine is an application field of converging technologies in translational medicine. It attempts to translate the results of tissue engineering to construct 3D tissues and organs. Regenerative medicine is also an exciting field for induced pluripotent stem cell (iPSC and promises to bring about a paradigm shift to health care. Accumulating evidence indicates that converging technologies will offer great potentials for regenerative medicine to create innovative treatments for diseases that the traditional therapies have not been effective yet.

  8. CONVERGENCE AND DIVERGENCE IN EUROPEAN UNION: EVIDENCE FOR BETA CONVERGENCE AMONG NEW EU MEMBER STATES

    Directory of Open Access Journals (Sweden)

    Ioana Sorina Mihuț

    2013-07-01

    Full Text Available Abstract: Convergence may be considered a central issue of the current economic literature, and not only, concentrating upon income distribution within different economies, but also focusing on different aspects of polarity and inequality that characterize especially the emerging economies. Testing convergence within economies may serve as a useful instrument for the validation of the economic growth models. While convergence was considered a defining element of the neoclassical growth models, the majority of the new endogenous growth models argue in favour of divergence across different economies. Testing convergence among European Union is even more challenging due to the high degree of heterogeneity that characterizes these economies. The recent accessions with ten new countries in 2004 and with another two in 2007 were considered only the first step towards assuring a sustainable convergence and finally adopting a common currency-the euro. A series of empirical studies concentrated upon testing convergence among EU, using as benchmark the real convergence quantified by the level of GDP/capita as an indicator for the living standards of every economy. The most popular approach rely on Beta and Sigma convergence, the first one being and indicator of the GDP/capita dispersion between different economies, and the later one being an estimator of the reverse relationship between GDP/capita and its initial level. The main purpose of this paper is to test Beta converge among the new EU member states, in order to obtained more information about the fact whether the poor countries are trying to catch-up with the more developed one. Also Beta convergence indicator embodies useful information about conditional and un-conditional convergence, two leading hypothesis within the neoclassical and endogenous growth models. For Beta convergence hypothesis to be valid it should be taken into consideration a ”catch-up” mechanism over a longer period of time

  9. On convergence of nuclear and correlation operators in Hilbert space

    International Nuclear Information System (INIS)

    Kubrusly, C.S.

    1985-01-01

    The convergence of sequences of nuclear operators on a separable Hilbert space is studied. Emphasis is given to trace-norm convergence, which is a basic property in stochastic systems theory. Obviously trace-norm convergence implies uniform convergence. The central theme of the paper focus the opposite way, by investigating when convergence in a weaker topology turns out to imply convergence in a stronger topology. The analysis carried out here is exhaustive in the following sense. All possible implications within a selected set of asymptotic properties for sequences of nuclear operators are established. The special case of correlation operators is also considered in detail. (Author) [pt

  10. The convergence of European business cycles 1978-2000

    Science.gov (United States)

    Ormerod, Paul; Mounfield, Craig

    2002-05-01

    The degree of convergence of the business cycles of the economies of the European Union (EU) is a key policy issue. In particular, a substantial degree of convergence is needed if the European Central Bank is to be capable of setting a monetary policy which is appropriate to the stage of the cycle of the Euro zone economies. We consider the annual rates of real GDP growth on a quarterly basis in the large core economies of the EU (France, Germany and Italy, plus The Netherlands) over the period 1978Q1-2000Q3. An important empirical question is the degree to which the correlations between these growth rates contain true information rather than noise. The technique of random matrix theory is able to answer this question, and has been recently applied successfully in the physics journals to financial markets data. We find that the correlations between the growth rates of the core EU economies contain substantial amounts of true information, and exhibit considerable stability over time. Even in the late 1970s and early 1980s, these economies moved together closely over the course of the business cycle. There was a slight loosening at the time of German re-unification, but the economies are now, if anything, even more closely correlated. As a benchmark for comparison, we add a series to the EU core data set which by construction is uncorrelated with these business cycles. We then analyse the EU core plus Spain, a country which has attached great importance to greater integration with Europe. In the early part of the period examined, the results are very similar to those obtained with the data set of the EU core plus the random series. However, there is a clear trend in the results, which provide strong evidence to support the view that the Spanish economy has now become closely converged with the core EU economies in terms of its movements over the business cycle. In contrast, the results obtained with a data set of the EU core plus the UK show no such trend. In the

  11. Computed tomography findings in convergent strabismus fixus

    International Nuclear Information System (INIS)

    Ohta, Michitaka; Iwashige, Hiroyasu; Hayashi, Takao; Maruo, Toshio

    1995-01-01

    X-ray computed tomography (CT) of the eyeball and orbit revealed the cause of eye movement disorder in convergent strabismus fixus. The findings suggest that the disease can be diagnosed and treated at an early stage. Twelve cases of progressive esotropia with high myopia and 20 cases with normal visual acuity served as subjects in this study. The CT slice was parallel to the German horizontal plane, and the lens and medial and lateral rectus muscles were scanned. The average axial length of the affected eyes was significantly longer than in normal eyes. In progressive esotropia, the characteristic CT findings are an elongated eyeball, mechanical contact between the eyeball and lateral wall of the orbit, and a downward displacement of the lateral rectus muscle. Thus, it is reasonable to conclude that eye movement disorder in convergent strabismus fixus results from weakness of the lateral rectus muscle which has been displaced downward due to compression of the eyeball against the orbital wall. (author)

  12. Generalized functions, convergence structures, and their applications

    CERN Document Server

    Pap, Endre; Pilipović, Stevan; Vladimirov, Vasilij; International Conference "Generalized functions, convergence structures and their applications" (GFCA-87)

    1988-01-01

    This Proceedings consists of a collection of papers presented at the International Conference "Generalized functions, convergence structures and their applications" held from June 23-27, 1987 in Dubrovnik, Yugoslavia (GFCA-87): 71 participants from 21 countr~es from allover the world took part in the Conference. Proceedings reflects the work of the Conference. Plenary lectures of J. Burzyk, J. F. Colombeau, W. Gahler, H. Keiter, H. Komatsu, B. Stankovic, H. G. Tillman, V. S. Vladimirov provide an up-to-date account of the cur­ rent state of the subject. All these lectures, except H. G. Tillman's, are published in this volume. The published communications give the contemporary problems and achievements in the theory of generalized functions, in the theory of convergence structures and in their applications, specially in the theory of partial differential equations and in the mathematical physics. New approaches to the theory of generalized functions are presented, moti­ vated by concrete problems of applicat...

  13. Molecular mechanisms involved in convergent crop domestication.

    Science.gov (United States)

    Lenser, Teresa; Theißen, Günter

    2013-12-01

    Domestication has helped to understand evolution. We argue that, vice versa, novel insights into evolutionary principles could provide deeper insights into domestication. Molecular analyses have demonstrated that convergent phenotypic evolution is often based on molecular changes in orthologous genes or pathways. Recent studies have revealed that during plant domestication the causal mutations for convergent changes in key traits are likely to be located in particular genes. These insights may contribute to defining candidate genes for genetic improvement during the domestication of new plant species. Such efforts may help to increase the range of arable crops available, thus increasing crop biodiversity and food security to help meet the predicted demands of the continually growing global population under rapidly changing environmental conditions. Copyright © 2013 Elsevier Ltd. All rights reserved.

  14. Flow over convergent and divergent wall riblets

    Energy Technology Data Exchange (ETDEWEB)

    Koeltzsch, K.; Dinkelacker, A.; Grundmann, R. [Institut fuer Luft- und Raumfahrttechnik, Technische Universitaet Dresden, 36460 Merkers (Germany)

    2002-08-01

    Fast swimming sharks have small riblets on their skin, which are assumed to improve the swimming performance of the fish. Fluid dynamic experiments in water as well as in air confirm this assumption. With riblet surfaces as compared to smooth surfaces, drag reductions up to about 10% were measured. The overall riblet pattern on sharks shows parallel riblets directed from head to tail, but besides this overall pattern fast swimming sharks have also small areas with converging riblets and others with diverging riblets. In the present study the velocity field over convergent and divergent riblet patterns is investigated by hot-wire measurements in turbulent pipe flow. Significant changes in the near wall velocity field were found. (orig.)

  15. Service Creation and Deployment in Converged Networks

    DEFF Research Database (Denmark)

    Soler, José

    for these experiences is the transition of telecommunication (telephony) networks from circuit switched based systems towards packet based ones. The text of this monograph proceeds, unaltered for the most, from the author’s PhD thesis “Framework for Deployment of Advanced Telecommunication Services in Current......This monograph (Early Experiences related to Service Creation & Deployment in Converged Networks) presents different experiences related to architectures and mechanisms for deployment of telephony services, understood as especial features complementing the basic voice service. The context...... and Future Converged Networks”, carried out at the Technical University of Denmark in the period [April 2002-April 2005]. Even though the technologies presented in the text have evolved from that period until now, the presented scenarios and setups are still valid as interesting initial steps in the realm....

  16. Convergent functional genomics of psychiatric disorders.

    Science.gov (United States)

    Niculescu, Alexander B

    2013-10-01

    Genetic and gene expression studies, in humans and animal models of psychiatric and other medical disorders, are becoming increasingly integrated. Particularly for genomics, the convergence and integration of data across species, experimental modalities and technical platforms is providing a fit-to-disease way of extracting reproducible and biologically important signal, in contrast to the fit-to-cohort effect and limited reproducibility of human genetic analyses alone. With the advent of whole-genome sequencing and the realization that a major portion of the non-coding genome may contain regulatory variants, Convergent Functional Genomics (CFG) approaches are going to be essential to identify disease-relevant signal from the tremendous polymorphic variation present in the general population. Such work in psychiatry can provide an example of how to address other genetically complex disorders, and in turn will benefit by incorporating concepts from other areas, such as cancer, cardiovascular diseases, and diabetes. © 2013 Wiley Periodicals, Inc.

  17. Stochastic convergence of persistence landscapes and silhouettes

    Directory of Open Access Journals (Sweden)

    Frédéric Chazal

    2015-03-01

    Full Text Available Persistent homology is a widely used tool in Topological Data Analysis that encodes multi-scale topological information as a multiset of points in the plane called a persistence diagram. It is difficult to apply statistical theory directly to a random sample of diagrams. Instead, we summarize persistent homology with a persistence landscape, introduced by Bubenik, which converts a diagram into a well-behaved real-valued function. We investigate the statistical properties of landscapes, such as weak convergence of the average landscapes and convergence of the bootstrap. In addition, we introduce an alternate functional summary of persistent homology, which we call the silhouette, and derive an analogous statistical theory.

  18. Emotional convergence between people over time.

    Science.gov (United States)

    Anderson, Cameron; Keltner, Dacher; John, Oliver P

    2003-05-01

    The authors propose that people in relationships become emotionally similar over time--as this similarity would help coordinate the thoughts and behaviors of the relationship partners, increase their mutual understanding, and foster their social cohesion. Using laboratory procedures to induce and assess emotional response, the authors found that dating partners (Study 1) and college roommates (Studies 2 and 3) became more similar in their emotional responses over the course of a year. Further, relationship partners with less power made more of the change necessary for convergence to occur. Consistent with the proposed benefits of emotional similarity, relationships whose partners were more emotionally similar were more cohesive and less likely to dissolve. Discussion focuses on implications of emotional convergence and on potential mechanisms.

  19. Electricity wholesale market prices in Europe: Convergence?

    International Nuclear Information System (INIS)

    Zachmann, Georg

    2008-01-01

    This paper tests the hypothesis that the ongoing restructuring process in the European electricity sector has led to a common European market for electricity. Based on a Principal Component Analysis (PCA) of wholesale electricity prices in 2002-2006, we reject the assumption of full market integration. For several pairs of countries, the weaker hypothesis of (bilateral) convergence is accepted based on unit root tests (KPSS and ADF) and a convergence test based on filtered pairwise price relations. This indicates that the efforts to develop a single European market for electricity were so far only partially successful. We show that the daily auction prices of scarce cross-border transmission capacities are insufficient to explain the persistence of international price differentials. Empirically, our findings confirm the insufficiency of explicit capacity auctions as stated in the theoretical literature. (author)

  20. Convergence of carbon dioxide emissions in different sectors in China

    International Nuclear Information System (INIS)

    Wang, Juan; Zhang, Kezhong

    2014-01-01

    In this paper, we analyze differences in per capita carbon dioxide emissions from 1996 to 2010 in six sectors across 28 provinces in China and examine the σ-convergence, stochastic convergence and β-convergence of these emissions. We also investigate the factors that impact the convergence of per capita carbon dioxide emissions in each sector. The results show that per capita carbon dioxide emissions in all sectors converged across provinces from 1996 to 2010. Factors that impact the convergence of per capita carbon dioxide emissions in each sector vary: GDP (gross domestic product) per capita, industrialization process and population density impact convergence in the Industry sector, while GDP per capita and population density impact convergence in the Transportation, Storage, Postal, and Telecommunications Services sector. Aside from GDP per capita and population density, trade openness also impacts convergence in the Wholesale, Retail, Trade, and Catering Service sector. Population density is the only factor that impacts convergence in the Residential Consumption sector. - Highlights: • Analyze differences in CO 2 emissions in six sectors among 28 provinces in China. • Examine the convergence of CO 2 emissions in six sectors. • Investigate factors impact on convergence of CO 2 emissions in each sector. • Factors impact on convergence of per capita CO 2 emissions in each sector vary

  1. Numerical convergence for a sewage disposal problem

    OpenAIRE

    Alvarez-Vázquez, L.J.; Martínez, A.; Rodríguez, C.; Vázquez-Méndez, M.E.

    2001-01-01

    The management of sewage disposal and the design of wastewater treatment systems can be formulated as a constrained pointwise optimal control problem. In this paper we study the convergence of the numerical resolution for the corresponding state system by means of a characteristics Galerkin method. The main difficulty of the problem is due to the existence of Radon measures in the right-hand side of the state system. Finally, we present numerical results for a realistic problem posed in a ria...

  2. COMPARATIVE FINANCIAL STATEMENTS. CONVERGENCE VERSUS DIVERGENCE

    Directory of Open Access Journals (Sweden)

    Nicolae ECOBICI

    2010-09-01

    Full Text Available In this paper I compared the Romanian financial statements with the US GAAP financial statements in terms of two criteria: first the reference period and secondly the shape, structure and content of financial statements. Nowadays the two accounting systems, the French and Anglo-Saxon, tend to harmonize. I will present the convergences and the divergences between the financial statements of Romania, subject to OMFP 3055/2009, in parallel with the Anglo-Saxon accounting system.

  3. Convolutional Dictionary Learning: Acceleration and Convergence

    Science.gov (United States)

    Chun, Il Yong; Fessler, Jeffrey A.

    2018-04-01

    Convolutional dictionary learning (CDL or sparsifying CDL) has many applications in image processing and computer vision. There has been growing interest in developing efficient algorithms for CDL, mostly relying on the augmented Lagrangian (AL) method or the variant alternating direction method of multipliers (ADMM). When their parameters are properly tuned, AL methods have shown fast convergence in CDL. However, the parameter tuning process is not trivial due to its data dependence and, in practice, the convergence of AL methods depends on the AL parameters for nonconvex CDL problems. To moderate these problems, this paper proposes a new practically feasible and convergent Block Proximal Gradient method using a Majorizer (BPG-M) for CDL. The BPG-M-based CDL is investigated with different block updating schemes and majorization matrix designs, and further accelerated by incorporating some momentum coefficient formulas and restarting techniques. All of the methods investigated incorporate a boundary artifacts removal (or, more generally, sampling) operator in the learning model. Numerical experiments show that, without needing any parameter tuning process, the proposed BPG-M approach converges more stably to desirable solutions of lower objective values than the existing state-of-the-art ADMM algorithm and its memory-efficient variant do. Compared to the ADMM approaches, the BPG-M method using a multi-block updating scheme is particularly useful in single-threaded CDL algorithm handling large datasets, due to its lower memory requirement and no polynomial computational complexity. Image denoising experiments show that, for relatively strong additive white Gaussian noise, the filters learned by BPG-M-based CDL outperform those trained by the ADMM approach.

  4. Isotropy analyses of the Planck convergence map

    Science.gov (United States)

    Marques, G. A.; Novaes, C. P.; Bernui, A.; Ferreira, I. S.

    2018-01-01

    The presence of matter in the path of relic photons causes distortions in the angular pattern of the cosmic microwave background (CMB) temperature fluctuations, modifying their properties in a slight but measurable way. Recently, the Planck Collaboration released the estimated convergence map, an integrated measure of the large-scale matter distribution that produced the weak gravitational lensing (WL) phenomenon observed in Planck CMB data. We perform exhaustive analyses of this convergence map calculating the variance in small and large regions of the sky, but excluding the area masked due to Galactic contaminations, and compare them with the features expected in the set of simulated convergence maps, also released by the Planck Collaboration. Our goal is to search for sky directions or regions where the WL imprints anomalous signatures to the variance estimator revealed through a χ2 analyses at a statistically significant level. In the local analysis of the Planck convergence map, we identified eight patches of the sky in disagreement, in more than 2σ, with what is observed in the average of the simulations. In contrast, in the large regions analysis we found no statistically significant discrepancies, but, interestingly, the regions with the highest χ2 values are surrounding the ecliptic poles. Thus, our results show a good agreement with the features expected by the Λ cold dark matter concordance model, as given by the simulations. Yet, the outliers regions found here could suggest that the data still contain residual contamination, like noise, due to over- or underestimation of systematic effects in the simulation data set.

  5. Design calculations for NIF convergent ablator experiments

    Directory of Open Access Journals (Sweden)

    Olson R.E.

    2013-11-01

    Full Text Available The NIF convergent ablation tuning effort is underway. In the early experiments, we have discovered that the design code simulations over-predict the capsule implosion velocity and shock flash ρr, but under-predict the hohlraum x-ray flux measurements. The apparent inconsistency between the x-ray flux and radiography data implies that there are important unexplained aspects of the hohlraum and/or capsule behavior.

  6. Arieti and Bowlby: convergence and direct influence.

    Science.gov (United States)

    Bacciagaluppi, Marco

    2015-09-01

    Arieti was a great specialist of schizophrenia and Bowlby was the initiator of attachment theory. Working independently on the two sides of the Atlantic, they converged on a range of topics, such as evolutionary theory, mourning, trauma, violence, and therapy as art and science. Later, Bowlby exerted a direct influence on Arieti, which Arieti acknowledged in his Love Can Be Found. Finally, the two authors cooperated in the second edition of the American Handbook of Psychiatry.

  7. ON STATISTICALLY CONVERGENT IN FINITE DIMENSIONAL SPACES

    OpenAIRE

    GÜNCAN, Ayşe Nur

    2009-01-01

    Abstract: In this paper, the notion of statistical convergence, which was introduced by Steinhaus (1951), was studied in Rm ; and some concepts and theorems, whose statistical correspondence for the real number sequences were given, were carried to Rm . In addition, the concepts of the statistical limit point and the statistical cluster point were given and it was mentioned that these two concepts were'nt equal in Fridy's study in 1993. These concepts were given in Rm and the i...

  8. Innovation diffusion, technological convergence and economic growth

    OpenAIRE

    R. Andergassen; F. Nardini; M. Ricottilli

    2013-01-01

    The paper investigates the mechanics through which novel technological principles are developed and diffused throughout an economy consisting of a technologically heterogeneous ensemble of firms. In the model entrepreneurs invest in the discovery and in the diffusion of a technological principle and their profit flow depends on how many firms adopt the innovation and on how long it takes other entrepreneurs to improve it. We show that technological convergence emerges from the competition amo...

  9. Guaranteed convergence of the Hough transform

    Science.gov (United States)

    Soffer, Menashe; Kiryati, Nahum

    1995-01-01

    The straight-line Hough Transform using normal parameterization with a continuous voting kernel is considered. It transforms the colinearity detection problem to a problem of finding the global maximum of a two dimensional function above a domain in the parameter space. The principle is similar to robust regression using fixed scale M-estimation. Unlike standard M-estimation procedures the Hough Transform does not rely on a good initial estimate of the line parameters: The global optimization problem is approached by exhaustive search on a grid that is usually as fine as computationally feasible. The global maximum of a general function above a bounded domain cannot be found by a finite number of function evaluations. Only if sufficient a-priori knowledge about the smoothness of the objective function is available, convergence to the global maximum can be guaranteed. The extraction of a-priori information and its efficient use are the main challenges in real global optimization problems. The global optimization problem in the Hough Transform is essentially how fine should the parameter space quantization be in order not to miss the true maximum. More than thirty years after Hough patented the basic algorithm, the problem is still essentially open. In this paper an attempt is made to identify a-priori information on the smoothness of the objective (Hough) function and to introduce sufficient conditions for the convergence of the Hough Transform to the global maximum. An image model with several application dependent parameters is defined. Edge point location errors as well as background noise are accounted for. Minimal parameter space quantization intervals that guarantee convergence are obtained. Focusing policies for multi-resolution Hough algorithms are developed. Theoretical support for bottom- up processing is provided. Due to the randomness of errors and noise, convergence guarantees are probabilistic.

  10. Convergence theorems for quasi-contractive mappings

    International Nuclear Information System (INIS)

    Chidume, C.E.

    1992-01-01

    It is proved that each of two well known fixed point iteration methods (the Mann and Ishikawa iteration methods) converges strongly, without any compactness assumption on the domain of the map, to the unique fixed point of a quasi-contractive map in real Banach spacers with property (U, α, m+1, m). These Banach spaces include the L p (or l p ) spaces, p ≥ 2. Our theorems generalize important known results. (author). 29 refs

  11. On the convergence in female participation rates

    OpenAIRE

    Abe, Yukiko

    2016-01-01

    Large regional differences exist in female participation across regions within Japan. This paper uses two datasets to show that a significant convergence in female participation took place from 1940 to 2010. Historically, urban areas have had low participation, whereas non-urban areas have had high participation. The participation rate rose steadily and significantly in urban areas and, to a lesser extent in non-urban areas, and as a result, regional differences shrank over time. The microdat...

  12. Gas-Electricity Convergence and foreclosure market

    International Nuclear Information System (INIS)

    Barquin Gil, J.

    2007-01-01

    Gas-electricity convergence is a relatively recent industrial trend. It can significantly increase energy sector efficiency. However, it also raises the possibility on anti-competitive behaviours. One of these problems is the so-called input foreclosure. It happens when a natural gas dominant firm restricts its access to its electricity sector competitors. This paper intends to briefly introduce the issue, with special focus in aspects relevant for the Spanish case. (Author)

  13. Testing Convergence Versus History: Convergence Dominates Phenotypic Evolution for over 150 Million Years in Frogs.

    Science.gov (United States)

    Moen, Daniel S; Morlon, Hélène; Wiens, John J

    2016-01-01

    Striking evolutionary convergence can lead to similar sets of species in different locations, such as in cichlid fishes and Anolis lizards, and suggests that evolution can be repeatable and predictable across clades. Yet, most examples of convergence involve relatively small temporal and/or spatial scales. Some authors have speculated that at larger scales (e.g., across continents), differing evolutionary histories will prevent convergence. However, few studies have compared the contrasting roles of convergence and history, and none have done so at large scales. Here we develop a two-part approach to test the scale over which convergence can occur, comparing the relative importance of convergence and history in macroevolution using phylogenetic models of adaptive evolution. We apply this approach to data from morphology, ecology, and phylogeny from 167 species of anuran amphibians (frogs) from 10 local sites across the world, spanning ~160 myr of evolution. Mapping ecology on the phylogeny revealed that similar microhabitat specialists (e.g., aquatic, arboreal) have evolved repeatedly across clades and regions, producing many evolutionary replicates for testing for morphological convergence. By comparing morphological optima for clades and microhabitat types (our first test), we find that convergence associated with microhabitat use dominates frog morphological evolution, producing recurrent ecomorphs that together encompass all sampled species in each community in each region. However, our second test, which examines whether and how much species differ from their inferred optima, shows that convergence is incomplete: that is, phenotypes of most species are still somewhat distant from the estimated optimum for each microhabitat, seemingly because of insufficient time for more complete adaptation (an effect of history). Yet, these effects of history are related to past ecologies, and not clade membership. Overall, our study elucidates the dominant drivers of

  14. Real Convergence, Steps from Adherence to Integration

    Directory of Open Access Journals (Sweden)

    Mihail Busu

    2016-05-01

    Full Text Available The macroeconomic model Solow-Swan shows that the marginal rates of capital, technology and labor force, with positive values, have the capacity to stimulate the economic growth of the emergent economies, as in the case of Romania, for the 2005-2014 period, facilitating the determination of specific correlations between macroeconomic indicators to analyze the convergence towards the average European Union (EU. The economic theory, highlighted in particular by the Solow-Swan model, was applied in the current paper, to determine the potential of real convergence. Moreover, the statistics for the period 2005-2014 facilitated the analysis of the growth and recession factors specific to economies of Central and Eastern Europe and placed Romania amongst the EU countries with emergent economies and potential of economic growth. The European Commission’s reports regarding the macroeconomic imbalance procedure draw attention on the same indicators presented in the article to address proper recommendations and support corrective measures. Making a step from nominal to real convergence, the latter derives naturally from the need to recoup the gaps in comparison with developed economies amongst countries of the Euro Area.

  15. Particle Acceleration in Two Converging Shocks

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xin; Wang, Na; Shan, Hao [Xinjiang Astronomical Observatory, Chinese Academy of Sciences, Urumqi 830011 (China); Giacalone, Joe [Lunar and Planetary Laboratory, University of Arizona, Tucson AZ 85721 (United States); Yan, Yihua [CAS Key Laboratory of Solar Activity, National Astronomical Observatories, Beijing 100012 (China); Ding, Mingde, E-mail: wangxin@xao.ac.cn [Key Laboratory of Modern Astronomy and Astrophysics (Nanjing University) Ministry of Education, Nanjing 210093 (China)

    2017-06-20

    Observations by spacecraft such as ACE , STEREO , and others show that there are proton spectral “breaks” with energy E {sub br} at 1–10 MeV in some large CME-driven shocks. Generally, a single shock with the diffusive acceleration mechanism would not predict the “broken” energy spectrum. The present paper focuses on two converging shocks to identify this energy spectral feature. In this case, the converging shocks comprise one forward CME-driven shock on 2006 December 13 and another backward Earth bow shock. We simulate the detailed particle acceleration processes in the region of the converging shocks using the Monte Carlo method. As a result, we not only obtain an extended energy spectrum with an energy “tail” up to a few 10 MeV higher than that in previous single shock model, but also we find an energy spectral “break” occurring on ∼5.5 MeV. The predicted energy spectral shape is consistent with observations from multiple spacecraft. The spectral “break,” then, in this case is caused by the interaction between the CME shock and Earth’s bow shock, and otherwise would not be present if Earth were not in the path of the CME.

  16. Non-LTE radiative transfer with lambda-acceleration - Convergence properties using exact full and diagonal lambda-operators

    Science.gov (United States)

    Macfarlane, J. J.

    1992-01-01

    We investigate the convergence properties of Lambda-acceleration methods for non-LTE radiative transfer problems in planar and spherical geometry. Matrix elements of the 'exact' A-operator are used to accelerate convergence to a solution in which both the radiative transfer and atomic rate equations are simultaneously satisfied. Convergence properties of two-level and multilevel atomic systems are investigated for methods using: (1) the complete Lambda-operator, and (2) the diagonal of the Lambda-operator. We find that the convergence properties for the method utilizing the complete Lambda-operator are significantly better than those of the diagonal Lambda-operator method, often reducing the number of iterations needed for convergence by a factor of between two and seven. However, the overall computational time required for large scale calculations - that is, those with many atomic levels and spatial zones - is typically a factor of a few larger for the complete Lambda-operator method, suggesting that the approach should be best applied to problems in which convergence is especially difficult.

  17. The Mackey convergence condition for spaces with webs

    Directory of Open Access Journals (Sweden)

    Thomas E. Gilsdorf

    1988-01-01

    Full Text Available If each sequence converging to 0 in a locally convex space is also Mackey convergent to 0, that space is said to satisfy the Mackey convergence condition. The problem of characterizing those locally convex spaces with this property is still open. In this paper, spaces with compatible webs are used to construct both a necessary and a sufficient condition for a locally convex space to satisfy the Mackey convergence condition.

  18. Convergence Analysis for the Multiplicative Schwarz Preconditioned Inexact Newton Algorithm

    KAUST Repository

    Liu, Lulu

    2016-10-26

    The multiplicative Schwarz preconditioned inexact Newton (MSPIN) algorithm, based on decomposition by field type rather than by subdomain, was recently introduced to improve the convergence of systems with unbalanced nonlinearities. This paper provides a convergence analysis of the MSPIN algorithm. Under reasonable assumptions, it is shown that MSPIN is locally convergent, and desired superlinear or even quadratic convergence can be obtained when the forcing terms are picked suitably.

  19. Convergence Analysis for the Multiplicative Schwarz Preconditioned Inexact Newton Algorithm

    KAUST Repository

    Liu, Lulu; Keyes, David E.

    2016-01-01

    The multiplicative Schwarz preconditioned inexact Newton (MSPIN) algorithm, based on decomposition by field type rather than by subdomain, was recently introduced to improve the convergence of systems with unbalanced nonlinearities. This paper provides a convergence analysis of the MSPIN algorithm. Under reasonable assumptions, it is shown that MSPIN is locally convergent, and desired superlinear or even quadratic convergence can be obtained when the forcing terms are picked suitably.

  20. The convergence of lattice solutions of linearised Regge calculus

    International Nuclear Information System (INIS)

    Barrett, J.W.; Williams, R.M.

    1988-01-01

    Sequences of configurations of linearised Regge calculus converging to plane wave solutions are constructed to illustrate an earlier result on convergence. It is shown that, for these examples, the convergence criterion filters out the solutions which do not satisfy Einstein's equations from those which do. (author)

  1. Rates of convergence of Brezier net over triangles

    International Nuclear Information System (INIS)

    Feng Yuyu.

    1986-12-01

    It is well known (Farin, 1979) that the sequence of Bezier nets f-circumflex n (x) associated with Bernstein-Bezier surface over a triangle converges to the surface uniformly as n goes to infinity. In this paper the precise rates of convergence are given. The pointwise convergence result and saturation theorem are presented. (author). 7 refs

  2. Convergent and Divergent Thinking in the Context of Narrative Mysteries

    Science.gov (United States)

    Wenzel, William G.; Gerrig, Richard J.

    2015-01-01

    This project demonstrates how narrative mysteries provide a context in which readers engage in creative cognition. Drawing on the concepts of convergent and divergent thinking, we wrote stories that had either convergent or divergent outcomes. For example, one story had a character give his girlfriend a ring (a convergent outcome), whereas the…

  3. Modelling Convergence of Finite Element Analysis of Cantilever Beam

    African Journals Online (AJOL)

    Convergence studies are carried out by investigating the convergence of numerical results as the number of elements is increased. If convergence is not obtained, the engineer using the finite element method has absolutely no indication whether the results are indicative of a meaningful approximation to the correct solution ...

  4. An Ensemble Approach in Converging Contents of LMS and KMS

    Science.gov (United States)

    Sabitha, A. Sai; Mehrotra, Deepti; Bansal, Abhay

    2017-01-01

    Currently the challenges in e-Learning are converging the learning content from various sources and managing them within e-learning practices. Data mining learning algorithms can be used and the contents can be converged based on the Metadata of the objects. Ensemble methods use multiple learning algorithms and it can be used to converge the…

  5. Convergence analysis of household expenditures using the absolute β-convergence method

    Directory of Open Access Journals (Sweden)

    Anto Domazet

    2012-01-01

    Full Text Available Background: The paper examines the convergence of household expenditures, in terms of a possible usage of the standardized, rather than consumer-tailored marketing, mainly on a regional level. Objectives: The main goal of this research is to study the existence of consumption expenditure convergence in the EU-27 countries, in the period between 2000 and 2007. Methods/Approach: The analysis used the absolute β-convergence method, in order to investigate the existence of a negative correlation between the growth over time in the overall consumption expenditure in EU member- countries for each individual product and service category and the initial expenditure level. Results: According to the obtained results, in the period between 2000 and 2007, the EU-27 countries reached a high level of consumer expenditure convergence, which provides a basis for developing a regional concept of the standardized international marketing for these countries’ markets. Conclusions: The results provide an empirical contribution to claims on consumer convergence in the countries included into economic integrations. Also, the obtained results can be used to create a basis for defining and applying the regional marketing concept for companies focusing on the EU-27 countries’ market.

  6. Societal response to nanotechnology: converging technologies–converging societal response research?

    International Nuclear Information System (INIS)

    Ronteltap, Amber; Fischer, Arnout R. H.; Tobi, Hilde

    2011-01-01

    Nanotechnology is an emerging technology particularly vulnerable to societal unrest, which may hinder its further development. With the increasing convergence of several technological domains in the field of nanotechnology, so too could convergence of social science methods help to anticipate societal response. This paper systematically reviews the current state of convergence in societal response research by first sketching the predominant approaches to previous new technologies, followed by an analysis of current research into societal response to nanotechnology. A set of 107 papers on previous new technologies shows that rational actor models have played an important role in the study of societal response to technology, in particular in the field of information technology and the geographic region of Asia. Biotechnology and nuclear power have, in contrast, more often been investigated through risk perception and other affective determinants, particularly in Europe and the USA. A set of 42 papers on societal response to nanotechnology shows similarities to research in biotechnology, as it also builds on affective variables such as risk perception. Although there is a tendency to extend the rational models with affective variables, convergence in social science approaches to response to new technologies still has a long way to go. The challenge for researchers of societal response to technologies is to converge to some shared principles by taking up the best parts from the rational actor models dominant in information technology, whilst integrating non-rational constructs from biotechnology research. The introduction of nanotechnology gives a unique opportunity to do so.

  7. Zoning Districts - Volusia County HUB Zones

    Data.gov (United States)

    NSGIC Local Govt | GIS Inventory — Historically Underutilized Business (HUB) Zones in Volusia County. Go to http://www.sba.gov/hubzone or contact the Department of Economic Development (386) 248-8048...

  8. Is the environmental performance of industrialized countries converging? A 'SURE' approach to testing for convergence

    International Nuclear Information System (INIS)

    Camarero, Mariam; Picazo-Tadeo, Andres J.; Tamarit, Cecilio

    2008-01-01

    In this paper, we test for convergence in the environmental performance of a sample of OECD countries, with data ranging from 1971 to 2002. First, we use Data Envelopment Analysis (DEA) to compute two environmental performance indicators (EPIs) in the production theory framework. Second, we propose the use of a sequential multivariate approach to test for convergence in environmental performance. These tests allow us to reconcile the time series literature with the cross-sectional dimension, which is basic when testing for convergence in regional blocs. The SURE technique is used, which allows for the existence of correlations across the series without imposing a common speed of mean reversion. The empirical results show that the group of countries as a whole, as well as the majority of countries considered on an individual basis (results for some countries vary between EPIs), are catching-up with Switzerland (the benchmark country). (author)

  9. Convergence of knowledge, technology and society beyond convergence of nano-bio-info-cognitive technologies

    CERN Document Server

    Bainbridge, William; Tonn, Bruce; Whitesides, George

    2013-01-01

    Convergence of knowledge and technology for the benefit of society (CKTS) is the core opportunity for progress in the 21st century, based on five principles: (1) the interdependence of all components of nature and society, (2) enhancement of creativity and innovation through evolutionary processes of convergence that combine existing principles, and divergence that generates new ones, (3) decision analysis for research and development based on system-logic deduction, (4) higher-level cross-domain languages to generate new solutions and support transfer of new knowledge, and (5) vision-inspired basic research embodied in grand challenges. Solutions are outlined for key societal challenges, including creating new industries and jobs, improving lifelong wellness and human potential, achieving personalized and integrated healthcare and education, and securing a sustainable quality of life for all. This report provides a ten-year “NBIC2” vision within a longer-term framework for converging technology and human...

  10. A Globally Convergent Matrix-Free Method for Constrained Equations and Its Linear Convergence Rate

    Directory of Open Access Journals (Sweden)

    Min Sun

    2014-01-01

    Full Text Available A matrix-free method for constrained equations is proposed, which is a combination of the well-known PRP (Polak-Ribière-Polyak conjugate gradient method and the famous hyperplane projection method. The new method is not only derivative-free, but also completely matrix-free, and consequently, it can be applied to solve large-scale constrained equations. We obtain global convergence of the new method without any differentiability requirement on the constrained equations. Compared with the existing gradient methods for solving such problem, the new method possesses linear convergence rate under standard conditions, and a relax factor γ is attached in the update step to accelerate convergence. Preliminary numerical results show that it is promising in practice.

  11. Convergence criteria for systems of nonlinear elliptic partial differential equations

    International Nuclear Information System (INIS)

    Sharma, R.K.

    1986-01-01

    This thesis deals with convergence criteria for a special system of nonlinear elliptic partial differential equations. A fixed-point algorithm is used, which iteratively solves one linearized elliptic partial differential equation at a time. Conditions are established that help foresee the convergence of the algorithm. Under reasonable hypotheses it is proved that the algorithm converges for such nonlinear elliptic systems. Extensive experimental results are reported and they show the algorithm converges in a wide variety of cases and the convergence is well correlated with the theoretical conditions introduced in this thesis

  12. Δim-lacunary statistical convergence of order α

    Science.gov (United States)

    Altınok, Hıfsı; Et, Mikail; Işık, Mahmut

    2018-01-01

    The purpose of this work is to introduce the concepts of Δim-lacunary statistical convergence of order α and lacunary strongly (Δim,p )-convergence of order α. We establish some connections between lacunary strongly (Δim,p )-convergence of order α and Δim-lacunary statistical convergence of order α. It is shown that if a sequence is lacunary strongly (Δim,p )-summable of order α then it is Δim-lacunary statistically convergent of order α.

  13. Convergence in energy consumption per capita among ASEAN countries

    International Nuclear Information System (INIS)

    Mishra, Vinod; Smyth, Russell

    2014-01-01

    We test for convergence in energy consumption per capita among ASEAN countries over the period 1971 to 2011 using the panel KPSS stationarity test and panel Lagrange multiplier (LM) unit root test. The results for the panel stationarity and unit root tests with structural breaks find support for energy convergence in ASEAN. - Highlights: • We test for convergence in energy consumption per capita among the ASEAN nations. • Univariate conventional unit root tests provide mixed evidence of convergence. • Panel unit root tests with structural breaks support convergence hypothesis

  14. Convergence theorems for Banach space valued integrable multifunctions

    Directory of Open Access Journals (Sweden)

    Nikolaos S. Papageorgiou

    1987-01-01

    Full Text Available In this work we generalize a result of Kato on the pointwise behavior of a weakly convergent sequence in the Lebesgue-Bochner spaces LXP(Ω (1≤p≤∞. Then we use that result to prove Fatou's type lemmata and dominated convergence theorems for the Aumann integral of Banach space valued measurable multifunctions. Analogous convergence results are also proved for the sets of integrable selectors of those multifunctions. In the process of proving those convergence theorems we make some useful observations concerning the Kuratowski-Mosco convergence of sets.

  15. Weak convergence and uniform normalization in infinitary rewriting

    DEFF Research Database (Denmark)

    Simonsen, Jakob Grue

    2010-01-01

    the starkly surprising result that for any orthogonal system with finitely many rules, the system is weakly normalizing under weak convergence if{f} it is strongly normalizing under weak convergence if{f} it is weakly normalizing under strong convergence if{f} it is strongly normalizing under strong...... convergence. As further corollaries, we derive a number of new results for weakly convergent rewriting: Systems with finitely many rules enjoy unique normal forms, and acyclic orthogonal systems are confluent. Our results suggest that it may be possible to recover some of the positive results for strongly...

  16. A Quadratically Convergent O(square root of nL-Iteration Algorithm for Linear Programming

    National Research Council Canada - National Science Library

    Ye, Y; Gueler, O; Tapia, Richard A; Zhang, Y

    1991-01-01

    ...)-iteration complexity while exhibiting superlinear convergence of the duality gap to zero under the assumption that the iteration sequence converges, and quadratic convergence of the duality gap...

  17. The convergent LEP and SPS control systems

    International Nuclear Information System (INIS)

    Altaber, J.

    1987-01-01

    The major design contraint of the control system for LEP is the compatibility with the existing SPS control system. The first reason for this compatibility is to allow a long term convergence of the SPS control system towards the LEP one. The second reason is to operate both LEP and SPS machines from a unique main control room. The distributed architecture of LEP and the existing SPS control systems are described. The design of the equipment interface for both machines is explained. Finally, the infrastructure of the common main control room for LEP and SPS is described

  18. Towards a convergence of world gas markets?

    International Nuclear Information System (INIS)

    Legros, E.

    2002-01-01

    This 7. summit of the world natural gas industry leaders was jointly organized by Petrostrategies, IFP-ENSPM (French institute of petroleum and national upper school of petroleum and engines), and SPTEC consulting. Three themes were debated: the natural gas market in Europe at the eve of the second directive (while the first directive has not been fully enforced), the world development of LNG market, the gas-electric power convergence and the effects of a growing up interdependence between both energy sources. (J.S.)

  19. Convergence as Organization: Blockupy against the ECB

    DEFF Research Database (Denmark)

    Harrison, Yannick Nehemiah Antonio; Risager, Bjarke Skærlund

    2016-01-01

    of organization: the Blockupy coalition, the participating formal and informal organizations, and the activist subject. This narrative explicates the mode of organization as a “convergence space” (cf. Routledge, 2003), with different “roots” and “routes” of organization (cf. Davies, 2012). Originality....../value – Thus, through an analysis of the modes of organization constituting this mass protest event, this paper restates the relevance of the concept of organization, which have recently been ignored or understated in favour of master-narratives of networks or the dichotomy of horizontalism and verticality...

  20. The converged Sn algorithm for nuclear criticality

    International Nuclear Information System (INIS)

    Ganapol, B. D.; Hadad, K.

    2009-01-01

    A new discrete ordinates algorithm to determine the multiplication factor of a 1D nuclear reactor, based on Bengt Carlson's S n method, is presented. The algorithm applies the Romberg and Wynn-epsilon accelerators to accelerate a 1D, one-group S n solution to its asymptotic limit. We demonstrate the feasibility of the Converged Sn (CSn) solution on several one-group criticality benchmark compilations. The new formulation is especially convenient since it enables highly accurate critical fluxes and eigenvalues using the most fundamental transport algorithm. (authors)

  1. Blind image deconvolution methods and convergence

    CERN Document Server

    Chaudhuri, Subhasis; Rameshan, Renu

    2014-01-01

    Blind deconvolution is a classical image processing problem which has been investigated by a large number of researchers over the last four decades. The purpose of this monograph is not to propose yet another method for blind image restoration. Rather the basic issue of deconvolvability has been explored from a theoretical view point. Some authors claim very good results while quite a few claim that blind restoration does not work. The authors clearly detail when such methods are expected to work and when they will not. In order to avoid the assumptions needed for convergence analysis in the

  2. Multimedia reviews: multimedia convergence for clinicians.

    Science.gov (United States)

    Taintor, Zebulon

    2003-12-01

    Introduction by the column editor: In this final column of the year, Dr. Taintor provides an overview of exciting technological developments via his report on the 2003 annual meeting of the American Association for Technology in Psychiatry (AATP). Advances-and convergences-in technology are providing clinicians with increasingly useful tools to enhance the effectiveness of their treatments, increase access to care, reduce errors, and save time. As Dr. Taintor notes, AATP's meeting is traditionally held in conjunction with the annual meeting of the American Psychiatric Association (APA). I hope that his report will encourage APA's members to attend some of next year's informative sessions.

  3. Can evolutionary convergence be tested on Europa?

    Energy Technology Data Exchange (ETDEWEB)

    Chela-Flores, Julian [Instituto de Estudios Avanzados, Caracas (Venezuela); [Abdus Salam International Centre for Theoretical Physics, Trieste (Italy)]. E-mail: chelaf@ictp.trieste.it

    2002-09-01

    A major objective in solar system exploration has to be the insertion of appropriate biology-oriented experiments in future missions. We discuss various reasons for suggesting that this type of research be considered a high priority for feasibility studies and, subsequently, for technological development of appropriate melters and submersibles. With the assumption that Darwin's theory is valid for the evolution of life anywhere in the universe, various degrees of convergent phenomena argue in favor of the conjecture that universal evolution of intelligent behavior is just a matter of time and preservation of steady planetary conditions. A preliminary test of this conjecture is feasible with experiments involving evolutionary biosignatures on Europa. (author)

  4. Exponentially Convergent Algorithms for Abstract Differential Equations

    CERN Document Server

    Gavrilyuk, Ivan; Vasylyk, Vitalii

    2011-01-01

    This book presents new accurate and efficient exponentially convergent methods for abstract differential equations with unbounded operator coefficients in Banach space. These methods are highly relevant for the practical scientific computing since the equations under consideration can be seen as the meta-models of systems of ordinary differential equations (ODE) as well as the partial differential equations (PDEs) describing various applied problems. The framework of functional analysis allows one to obtain very general but at the same time transparent algorithms and mathematical results which

  5. Is the 2MASS dipole convergent?

    OpenAIRE

    Chodorowski, Michał; Bilicki, Maciej; Mamon, Gary A.; Jarrett, Thomas

    2010-01-01

    We study the growth of the clustering dipole of galaxies from the Two Micron All Sky Survey (2MASS). We find that the dipole does not converge before the completeness limit of the 2MASS Extended Source Catalog, i.e. up to about 300 Mpc/h. We compare the observed growth of the dipole with the theoretically expected, conditional growth for the LambdaCDM power spectrum and cosmological parameters constrained by WMAP. The observed growth turns out to be within 1-sigma confidence level of the theo...

  6. Reble, a radially converging electron beam accelerator

    International Nuclear Information System (INIS)

    Ramirez, J.J.; Prestwich, K.R.

    1976-01-01

    The Reble accelerator at Sandia Laboratories is described. This accelerator was developed to provide an experimental source for studying the relevant diode physics, beam propagation, beam energy deposition in a gas using a radially converging e-beam. The nominal parameters for Reble are 1 MV, 200 kA, 20 ns e-beam pulse. The anode and cathode are concentric cylinders with the anode as the inner cylinder. The radial beam can be propagated through the thin foil anode into the laser gas volume. The design and performance of the various components of the accelerator are presented

  7. Cubature on Wiener Space: Pathwise Convergence

    International Nuclear Information System (INIS)

    Bayer, Christian; Friz, Peter K.

    2013-01-01

    Cubature on Wiener space (Lyons and Victoir in Proc. R. Soc. Lond. A 460(2041):169–198, 2004) provides a powerful alternative to Monte Carlo simulation for the integration of certain functionals on Wiener space. More specifically, and in the language of mathematical finance, cubature allows for fast computation of European option prices in generic diffusion models.We give a random walk interpretation of cubature and similar (e.g. the Ninomiya–Victoir) weak approximation schemes. By using rough path analysis, we are able to establish weak convergence for general path-dependent option prices.

  8. Morphological convergence in ‘river dolphin’ skulls

    Directory of Open Access Journals (Sweden)

    Charlotte E. Page

    2017-11-01

    Full Text Available Convergent evolution can provide insights into the predictability of, and constraints on, the evolution of biodiversity. One striking example of convergence is seen in the ‘river dolphins’. The four dolphin genera that make up the ‘river dolphins’ (Inia geoffrensis, Pontoporia blainvillei, Platanista gangetica and Lipotes vexillifer do not represent a single monophyletic group, despite being very similar in morphology. This has led many to using the ‘river dolphins’ as an example of convergent evolution. We investigate whether the skulls of the four ‘river dolphin’ genera are convergent when compared to other toothed dolphin taxa in addition to identifying convergent cranial and mandibular features. We use geometric morphometrics to uncover shape variation in the skulls of the ‘river dolphins’ and then apply a number of phylogenetic techniques to test for convergence. We find significant convergence in the skull morphology of the ‘river dolphins’. The four genera seem to have evolved similar skull shapes, leading to a convergent morphotype characterised by elongation of skull features. The cause of this morphological convergence remains unclear. However, the features we uncover as convergent, in particular elongation of the rostrum, support hypotheses of shared feeding mode or diet and thus provide the foundation for future work into convergence within the Odontoceti.

  9. Introduction to the structures and processes of subduction zones

    Science.gov (United States)

    Zheng, Yong-Fei; Zhao, Zi-Fu

    2017-09-01

    Subduction zones have been the focus of many studies since the advent of plate tectonics in 1960s. Workings within subduction zones beneath volcanic arcs have been of particular interest because they prime the source of arc magmas. The results from magmatic products have been used to decipher the structures and processes of subduction zones. In doing so, many progresses have been made on modern oceanic subduction zones, but less progresses on ancient oceanic subduction zones. On the other hand, continental subduction zones have been studied since findings of coesite in metamorphic rocks of supracrustal origin in 1980s. It turns out that high-pressure to ultrahigh-pressure metamorphic rocks in collisional orogens provide a direct target to investigate the tectonism of subduction zones, whereas oceanic and continental arc volcanic rocks in accretionary orogens provide an indirect target to investigate the geochemistry of subduction zones. Nevertheless, metamorphic dehydration and partial melting at high-pressure to ultrahigh-pressure conditions are tectonically applicable to subduction zone processes at forearc to subarc depths, and crustal metasomatism is the physicochemical mechanism for geochemical transfer from the slab to the mantle in subduction channels. Taken together, these provide us with an excellent opportunity to find how the metamorphic, metasomatic and magmatic products are a function of the structures and processes in both oceanic and continental subduction zones. Because of the change in the thermal structures of subduction zones, different styles of metamorphism, metasomatism and magmatism are produced at convergent plate margins. In addition, juvenile and ancient crustal rocks have often suffered reworking in episodes independent of either accretionary or collisional orogeny, leading to continental rifting metamorphism and thus rifting orogeny for mountain building in intracontinental settings. This brings complexity to distinguish the syn

  10. OpenMC In Situ Source Convergence Detection

    Energy Technology Data Exchange (ETDEWEB)

    Aldrich, Garrett Allen [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Univ. of California, Davis, CA (United States); Dutta, Soumya [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); The Ohio State Univ., Columbus, OH (United States); Woodring, Jonathan Lee [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-05-07

    We designed and implemented an in situ version of particle source convergence for the OpenMC particle transport simulator. OpenMC is a Monte Carlo based-particle simulator for neutron criticality calculations. For the transport simulation to be accurate, source particles must converge on a spatial distribution. Typically, convergence is obtained by iterating the simulation by a user-settable, fixed number of steps, and it is assumed that convergence is achieved. We instead implement a method to detect convergence, using the stochastic oscillator for identifying convergence of source particles based on their accumulated Shannon Entropy. Using our in situ convergence detection, we are able to detect and begin tallying results for the full simulation once the proper source distribution has been confirmed. Our method ensures that the simulation is not started too early, by a user setting too optimistic parameters, or too late, by setting too conservative a parameter.

  11. Convergent evolution of the genomes of marine mammals

    Science.gov (United States)

    Foote, Andrew D.; Liu, Yue; Thomas, Gregg W.C.; Vinař, Tomáš; Alföldi, Jessica; Deng, Jixin; Dugan, Shannon; van Elk, Cornelis E.; Hunter, Margaret; Joshi, Vandita; Khan, Ziad; Kovar, Christie; Lee, Sandra L.; Lindblad-Toh, Kerstin; Mancia, Annalaura; Nielsen, Rasmus; Qin, Xiang; Qu, Jiaxin; Raney, Brian J.; Vijay, Nagarjun; Wolf, Jochen B. W.; Hahn, Matthew W.; Muzny, Donna M.; Worley, Kim C.; Gilbert, M. Thomas P.; Gibbs, Richard A.

    2015-01-01

    Marine mammals from different mammalian orders share several phenotypic traits adapted to the aquatic environment and therefore represent a classic example of convergent evolution. To investigate convergent evolution at the genomic level, we sequenced and performed de novo assembly of the genomes of three species of marine mammals (the killer whale, walrus and manatee) from three mammalian orders that share independently evolved phenotypic adaptations to a marine existence. Our comparative genomic analyses found that convergent amino acid substitutions were widespread throughout the genome and that a subset of these substitutions were in genes evolving under positive selection and putatively associated with a marine phenotype. However, we found higher levels of convergent amino acid substitutions in a control set of terrestrial sister taxa to the marine mammals. Our results suggest that, whereas convergent molecular evolution is relatively common, adaptive molecular convergence linked to phenotypic convergence is comparatively rare.

  12. Geophysical characteristics of the Ninetyeast Ridge–Andaman island arc/trench convergent zone

    Digital Repository Service at National Institute of Oceanography (India)

    Subrahmanyam, C.; Gireesh, R.; Chand, S.; KameshRaju, K.A.; Rao, D.G.

    ] N. Furus, Y. Kono, Slab residual gravity anomaly: gravity reduction due to subducting plates beneath the Japanese Islands, J. Geodyn. 36 (2003) 497-514. 19 [15] S Dasgupta, M. Mukhopadhyay, A. Bhattacharya, T. K. Jana, The geometry...

  13. Atlanta ariejansseni, a new species of shelled heteropod from the Southern Subtropical Convergence Zone (Gastropoda, Pterotracheoidea)

    NARCIS (Netherlands)

    Wall-Palmer, D.; Burridge, A.K.; Peijnenburg, K.T.C.A.

    2016-01-01

    The Atlantidae (shelled heteropods) is a family of microscopic aragonite shelled holoplanktonic gastropods with a wide biogeographical distribution in tropical, sub-tropical and temperate waters. The aragonite shell and surface ocean habitat of the atlantids makes them particularly susceptible to

  14. ENSO influence on the interannual variability of the Red Sea convergence zone and associated rainfall

    KAUST Repository

    Dasari, Hari Prasad; Langodan, Sabique; Viswanadhapalli, Yesubabu; Vadlamudi, Brahmananda R.; Papadopoulos, Vassilis P.; Hoteit, Ibrahim

    2017-01-01

    trough (RST), transfers moisture from the southern Red Sea to RSCZ. The positions of the RSCZ and RST and the intensity of the RST have been identified as important factors in modulating weather and climatic conditions across the Middle East. Here, we

  15. Interannual variability of the South Pacific Convergence Zone and implications for tropical cyclone genesis

    Digital Repository Service at National Institute of Oceanography (India)

    Vincent, E.M.; Lengaigne, M.; Menkes, C.E.; Jourdain, N.C.; Marchesiello, P.; Madec, G.

    SPCZ con- trols the large scale environment favouring cyclonic activity have not yet been investigated. In addition, the characteristics of El Nin˜o events vary widely from one event to another, and the influence of this diversity on the SPCZ location... which the classification is performed) accu- rately summarizes the large-scale precipitation variability in the tropical South Pacific (on which the EOFs are con- structed). The same AHC applied to PC1–PC2 coordinates instead of latW–latE indices gives...

  16. Converging social classes through humanized urban edges

    Science.gov (United States)

    Abuan, M. V.; Galingan, Z. D.

    2017-10-01

    Urban open spaces are created to be used by people. It is a place of convergence and social activity. However, these places have transformed into places of divergence. When spaces become dehumanized, it separates social classes. As a result, underused spaces contribute to urban decay. Particularly an urban edge, the JP Rizal Makati Waterfront Area is the center of this paper. The JP Rizal Makati Waterfront Area is a waterfront development situated along the banks of one of Metro Manila’s major water thoroughfare --- Pasig River. The park and its physical form, urban design and landscape tend to deteriorate over time --- creating a further division of social convergence. Social hostility, crime, negligent maintenance and poor urban design are contributing factors to this sprawling decay in what used to be spaces of bringing people together. Amidst attempts to beautify and renew this portion of Makati City’s edge, the urban area still remains misspent.This paper attempts to re-humanize the waterfront development. It uses the responsive environment design principles to be able to achieve this goal.

  17. CONVERGENCE IN THE EUROPEAN SOCIAL POLICY

    Directory of Open Access Journals (Sweden)

    Mariana Iovitu

    2012-07-01

    Full Text Available The European Union has developed a series of strategies that aim to limit the consequences of non-employment (due to the continuing crisis. These strategies aim by the objectives and mechanisms specific to the eco-social area, to improve the access to employment, social services, professional education and a more efficient European fund management. All this are subordinated to the coupling policy public-private in terms of partnerships both at a national level and European level. The problem is related to differences manifested between the social objectives at the national level and those imposed by the European context. The differences come from different degrees of economic development of the member states, economic development which is reflected on the living standards. The convergence between the social policies is based on the economic convergence, which represents the only way to ameliorate the discrepancies between the united nations of Europe. Social Europe dream or certainty? The answer can be found in the words of Jean Monnet: “we are not bringing together states, we are uniting people”. The efforts to define the four types of actions regarding the free movement of labor force and the correlation of the social security schemes, ensuring equal opportunities, respecting labor rights and the fight against discrimination can be found in the results obtained on these priorities.

  18. Convergences in the diversification of bats

    Directory of Open Access Journals (Sweden)

    M. Brock FENTON

    2010-08-01

    Full Text Available Twenty-five characters or suites of characters from bats are considered in light of changes in bat classification. The characters include some associated with flower-visiting (two, echolocation (12, roosting (six, reproduction (two and three are of unknown adaptive function. In both the 1998 and 2006 classifications of bats into suborders (Megachiroptera and Microchiroptera versus Yinpterochiroptera and Yangochiroptera, respectively, some convergences between suborders are the same (e.g., foliage roosting, tent building, but others associated with echolocation differ substantially. In the 1998 phylogeny convergences associated with echolocation (high duty cycle echolocation, nasal emission of echolocation calls occurred among the Microchiroptera. In the 2006 phylogeny, they occur between Yinpterochiroptera and Yangochiroptera. While some traits apparently arose independently in two suborders (e.g., foliage-roosting, tent building, low intensity echolocation calls, noseleafs, nasal emission of echolocation calls, high duty cycle echolocation behaviour, others appear to have been ancestral (roosting in narrow spaces, laryngeal echolocation, stylohyal-tympanic contact, oral emission of echolocation calls, and small litter size. A narrow profile through the chest is typical of bats reflecting the thoracic skeleton. This feature suggests that the ancestors of bats spent the day in small crevices. Features associated with laryngeal echolocation appear to be ancestral, suggesting that echolocation evolved early in bats but was subsequently lost in one yinpterochiropteran lineage [Current Zoology 56 (4: 454–468, 2010].

  19. Regional Convergence of Income: Spatial Analysis

    Directory of Open Access Journals (Sweden)

    Vera Ivanovna Ivanova

    2014-12-01

    Full Text Available Russia has a huge territory and a strong interregional heterogeneity, so we can assume that geographical factors have a significant impact on the pace of economic growth in Russian regions. Therefore the article is focused on the following issues: 1 correlation between comparative advantages of geographical location and differences in growth rates; 2 impact of more developed regions on their neighbors and 3 correlation between economic growth of regions and their spatial interaction. The article is devoted to the empirical analysis of regional per capita incomes from 1996 to 2012 and explores the dynamics of the spatial autocorrelation of regional development indicator. It is shown that there is a problem of measuring the intensity of spatial dependence: factor value of Moran’s index varies greatly depending on the choice of the matrix of distances. In addition, with the help of spatial econometrics the author tests the following hypotheses: 1 there is convergence between regions for a specified period; 2 the process of beta convergence is explained by the spatial arrangement of regions and 3 there is positive impact of market size on regional growth. The author empirically confirmed all three hypotheses

  20. The convergence theory for vitiligo: A reappraisal.

    Science.gov (United States)

    Kundu, Roopal V; Mhlaba, Julia M; Rangel, Stephanie M; Le Poole, I Caroline

    2018-04-28

    Vitiligo is characterized by progressive loss of skin pigmentation. The search for etiologic factors has led to the biochemical, the neurologic and the autoimmune theory. The convergence theory was then proposed several years ago to incorporate existing theories of vitiligo development into a single overview of vitiligo etiology. The viewpoint that vitiligo is not caused only by predisposing mutations, or only by melanocytes responding to chemical/radiation exposure, or only by hyperreactive T cells, but rather results from a combination of etiologic factors that impact melanocyte viability, has certainly stood the test of time. New findings have since informed the description of progressive depigmentation. Understanding the relative importance of such etiologic factors combined with a careful selection of the most targetable pathways will continue to drive the next phase in vitiligo research: the development of effective therapeutics. In that arena it is likewise important to acknowledge that pathways affected in some patients may not be altered in others. Taken together, the convergence theory continues to provide a comprehensive viewpoint of vitiligo etiology. The theory serves to intertwine etiologic pathways and will help to define pathways amenable to disease intervention in individual patients. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  1. Symbolic convergence and the hydrogen economy

    International Nuclear Information System (INIS)

    Sovacool, Benjamin K.; Brossmann, Brent

    2010-01-01

    This article documents that the hydrogen economy continues to attract significant attention among politicians, the media, and some academics. We believe that an explanation lies in the way that the hydrogen economy fulfills psychological and cultural needs related to a future world where energy is abundant, cheap, and pollution-free, a 'fantasy' that manifests itself with the idea that society can continue to operate without limits imposed by population growth and the destruction of the environment. The article begins by explaining its research methodology consisting of two literature reviews, research interviews of energy experts, and the application of symbolic convergence theory, a general communications theory about the construction of rhetorical fantasies. We then identify a host of socio-technical challenges to explain why the creation of a hydrogen economy would present immense (and possibly intractable) obstacles, an argument supplemented by our research interviews. Next, we employ symbolic convergence theory to identify five prevalent fantasy themes and rhetorical visions-independence, patriotism, progress, democratization, and inevitability-in academic and public discussions in favor of the hydrogen economy. We conclude by offering implications for scholarship relating to energy policy more broadly.

  2. Convergence almost everywhere of multidimensional vectors

    International Nuclear Information System (INIS)

    El Berdan, Kassem; Zeineddine, Hassan

    2000-01-01

    Let X be a reflexive Banach space, Ω a measure space, T 1 ,...,T d be linear not commuting operators on L 1 (Ω,X)=L 1 (X) which are strictly contracting in L 1 (X) (i.e. there exist αjbelong to ]0,1[ such that ||T j f||≤αj||f|| for all j=1....,d and f belong to L 1 (X), and contracting in L ∞ (X). We prove a maximal equality for the averages: A n (T 1 ,...,T d )f= n d /1 i1=0 Σ n-1 ... id=0 Σ n-1 T 1 i1 ...T d id f and the convergence almost everywhere of it for all f in L 1 (X). This result generalizes Chacon's theorem (Chacon 19620 to the multidimensional case for this operators class. Finally, we give two operators which are strictly contracting in L 1 (X) and contracting in L ∞ (X) such that the convergence of the averages is not trivial. (author)

  3. Towards stacked zone plates

    International Nuclear Information System (INIS)

    Werner, S; Rehbein, S; Guttman, P; Heim, S; Schneider, G

    2009-01-01

    Fresnel zone plates are the key optical elements for soft and hard x-ray microscopy. For short exposure times and minimum radiation load of the specimen the diffraction efficiency of the zone plate objectives has to be maximized. As the efficiency strongly depends on the height of the diffracting zone structures the achievable aspect ratio of the nanostructures determines these limits. To reach aspect ratios ≥ 20:1 for high efficient optics we propose to superimpose zone plates on top of each other. With this multiplication approach the final aspect ratio is only limited by the number of stacked zone plate layers. For the stack process several nanostructuring process steps have to be developed and/or improved. Our results show for the first time two layers of zone plates stacked on top of each other.

  4. Contrast of HOLZ lines in energy-filtered convergent-beam electron diffraction patterns from silicon

    International Nuclear Information System (INIS)

    Lehmpfuhl, G.; Krahl, D.; Uchida, Y.

    1995-01-01

    Higher-order Laue-zone (HOLZ) lines were investigated in convergent-beam electron diffraction patterns from silicon near the low-indexed zone axes [100], [110] and [111]. The visibility of these lines depends on the effective structure potentials of the reflections from the first Laue zone depending on their Debye-Waller factor. The contrast of the HOLZ lines is strongly reduced by inelastically scattered electrons. They can be excluded by an imaging Ω filter for energy losses above 2 eV. The diffraction patterns were compared with many-beam calculations. Without absorption, an excellent agreement could be achieved for the [111] and [100] zone axes, while the simulation of the [110] zone-axis pattern needed a calculation with absorption. The reason for this observation is explained in the Bloch-wave picture. Calculations with absorption, however, lead to artefacts in the intensity distribution of the [100] HOLZ pattern. In order to obtain agreement with the experiment, the Debye-Waller factor had to be modified in different ways for the different zone axes. This corresponds to a strong anisotropy of the Debye-Waller factor. To confirm this observation, the temperature dependence of the itensity distributions of the HOLZ patterns was investigated between 50 and 680 K. At room temperature, the parameter D in the Debye-Waller factor exp(-Ds 2 ) was determined as 0.13, 0.26 and 0.55 A 2 for the zone axes [100], [111] and [110], respectively. The reliability of the conclusions is discussed. (orig.)

  5. ZoneLib

    DEFF Research Database (Denmark)

    Jessen, Jan Jacob; Schiøler, Henrik

    2006-01-01

    We present a dynamic model for climate in a livestock building divided into a number of zones, and a corresponding modular Simulink library (ZoneLib). While most literature in this area consider air flow as a control parameter we show how to model climate dynamics using actual control signals...... development of ZoneLib....

  6. Electricity and gas : market and price convergence : fundamentals of restructuring and convergence

    Energy Technology Data Exchange (ETDEWEB)

    Heintz, H.; Spragins, R.

    2000-07-01

    One of the results of the transition from regulation to competition in the Canadian and American natural gas and electricity industries is convergence of the two industries. Convergence is occurring in the areas of corporate structuring activities (mergers and acquisitions), natural gas and electricity prices, products and services, and on a geographic basis. This study examines the restructuring and convergence from the perspective of industry stakeholders, consumers, competitors and regulators. The trend to deregulate to establish competitive markets has been driven by the assumption that lower prices and more choices will result. Deregulation has been made easier by technological developments and innovations in the area of conventional generation, distributed generation, information management and analysis, as well as mass communication channels such as the Internet. These changes have made it possible to measure and monitor energy use in real-time. Technological changes will continue to influence the energy industry. The use of different restructuring rules and regulations in jurisdictions that are implementing change may be one of the primary factors that could limit the extent of convergence. Successful competition by energy service providers in converged retail energy markets will depend on several factors, the first of which is the ability to control the customer interface through retail cycle services such as metering and billing. The second is the successful branding of corporate identities, products and services. These will ensure customer loyalty and facilitate the marketing of new products. Another factor would be the effective management of information regarding natural gas and electricity consumption patterns and the establishment of low cost operations through the use of conventional generation technologies. The final factor for successful competition is the effective use of low cost communication technologies such as the Internet. The transition

  7. Reduced vergence adaptation is associated with a prolonged output of convergence accommodation in convergence insufficiency.

    Science.gov (United States)

    Sreenivasan, Vidhyapriya; Bobier, William R

    2014-07-01

    Convergence insufficiency (CI) is a developmental visual anomaly defined clinically by a reduced near point of convergence, a reduced capacity to view through base-out prisms (fusional convergence); coupled with asthenopic symptoms typically blur and diplopia. Experimental studies show reduced vergence parameters and tonic adaptation. Based upon current models of accommodation and vergence, we hypothesize that the reduced vergence adaptation in CI leads to excessive amounts of convergence accommodation (CA). Eleven CI participants (mean age=17.4±2.3 years) were recruited with reduced capacity to view through increasing magnitudes of base out (BO) prisms (mean fusional convergence at 40 cm=12±0.9Δ). Testing followed our previous experimental design for (n=11) binocularly normal adults. Binocular fixation of a difference of Gaussian (DoG) target (0.2 cpd) elicited CA responses during vergence adaptation to a 12Δ BO. Vergence and CA responses were obtained at 3 min intervals over a 15 min period and time course were quantified using exponential decay functions. Results were compared to previously published data on eleven binocular normals. Eight participants completed the study. CI's showed significantly reduced magnitude of vergence adaptation (CI: 2.9Δ vs. normals: 6.6Δ; p=0.01) and CA reduction (CI=0.21 D, Normals=0.55 D; p=0.03). However, the decay time constants for adaptation and CA responses were not significantly different. CA changes were not confounded by changes in tonic accommodation (Change in TA=0.01±0.2D; p=0.8). The reduced magnitude of vergence adaptation found in CI patients resulting in higher levels of CA may potentially explain their clinical findings of reduced positive fusional vergence (PFV) and the common symptom of blur. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Electricity and gas : market and price convergence : fundamentals of restructuring and convergence

    International Nuclear Information System (INIS)

    Heintz, H.; Spragins, R.

    2000-01-01

    One of the results of the transition from regulation to competition in the Canadian and American natural gas and electricity industries is convergence of the two industries. Convergence is occurring in the areas of corporate structuring activities (mergers and acquisitions), natural gas and electricity prices, products and services, and on a geographic basis. This study examines the restructuring and convergence from the perspective of industry stakeholders, consumers, competitors and regulators. The trend to deregulate to establish competitive markets has been driven by the assumption that lower prices and more choices will result. Deregulation has been made easier by technological developments and innovations in the area of conventional generation, distributed generation, information management and analysis, as well as mass communication channels such as the Internet. These changes have made it possible to measure and monitor energy use in real-time. Technological changes will continue to influence the energy industry. The use of different restructuring rules and regulations in jurisdictions that are implementing change may be one of the primary factors that could limit the extent of convergence. Successful competition by energy service providers in converged retail energy markets will depend on several factors, the first of which is the ability to control the customer interface through retail cycle services such as metering and billing. The second is the successful branding of corporate identities, products and services. These will ensure customer loyalty and facilitate the marketing of new products. Another factor would be the effective management of information regarding natural gas and electricity consumption patterns and the establishment of low cost operations through the use of conventional generation technologies. The final factor for successful competition is the effective use of low cost communication technologies such as the Internet. The transition

  9. Real Economic Convergence in Western Europe from 1995 to 2013

    Directory of Open Access Journals (Sweden)

    Dzenita Siljak

    2016-05-01

    Full Text Available The aim of the paper is to analyze the economic convergence of real per capita GDP in the Western European countries with two types of measurement methodology. The first is sigma convergence, based on the coefficient of variation of real per capita GDP. The second is beta convergence, absolute/unconditional and conditional, including economic and socio-political variables, based on the neoclassical growth theory. The hypothesis of the paper is that there has been real economic convergence in Western Europe in at least one analyzed sub-period. The relationships between selected macroeconomic variables and the rate of economic growth are econometrically tested. Both sigma and beta convergence are estimated for the period 1995-2013 and four sub-periods: 1995-2003, 2004-2013, pre-crisis sub-period 2004-2008 and the crisis sub-period 2009-2013. The empirical findings support the hypothesis of economic convergence, i.e. that the poorer countries tend to grow faster than the rich ones in per capita terms, for some periods. However, the countries had a tendency to diverge, confiriming the negative effects of the crisis on per capita GDP growth. Sigma convergence is consistent with beta convergence. According to the results, the half-life of real convergence may take from 12 to 1078 years. Significant dissimilarities between the growth patterns among individual countries show the considerable heterogeneity of growth, i.e. the convergence clubs.

  10. Converging shocks in elastic-plastic solids.

    Science.gov (United States)

    Ortega, A López; Lombardini, M; Hill, D J

    2011-11-01

    We present an approximate description of the behavior of an elastic-plastic material processed by a cylindrically or spherically symmetric converging shock, following Whitham's shock dynamics theory. Originally applied with success to various gas dynamics problems, this theory is presently derived for solid media, in both elastic and plastic regimes. The exact solutions of the shock dynamics equations obtained reproduce well the results obtained by high-resolution numerical simulations. The examined constitutive laws share a compressible neo-Hookean structure for the internal energy e=e(s)(I(1))+e(h)(ρ,ς), where e(s) accounts for shear through the first invariant of the Cauchy-Green tensor, and e(h) represents the hydrostatic contribution as a function of the density ρ and entropy ς. In the strong-shock limit, reached as the shock approaches the axis or origin r=0, we show that compression effects are dominant over shear deformations. For an isothermal constitutive law, i.e., e(h)=e(h)(ρ), with a power-law dependence e(h) is proportional to ρ(α), shock dynamics predicts that for a converging shock located at r=R(t) at time t, the Mach number increases as M is proportional to [log(1/R)](α), independently of the space index s, where s=2 in cylindrical geometry and 3 in spherical geometry. An alternative isothermal constitutive law with p(ρ) of the arctanh type, which enforces a finite density in the strong-shock limit, leads to M is proportional to R(-(s-1)) for strong shocks. A nonisothermal constitutive law, whose hydrostatic part e(h) is that of an ideal gas, is also tested, recovering the strong-shock limit M is proportional to R(-(s-1)/n(γ)) originally derived by Whitham for perfect gases, where γ is inherently related to the maximum compression ratio that the material can reach, (γ+1)/(γ-1). From these strong-shock limits, we also estimate analytically the density, radial velocity, pressure, and sound speed immediately behind the shock. While the

  11. Biomedical engineering frontier research and converging technologies

    CERN Document Server

    Jun, Ho-Wook; Shin, Jennifer; Lee, SangHoon

    2016-01-01

    This book provides readers with an integrative overview of the latest research and developments in the broad field of biomedical engineering. Each of the chapters offers a timely review written by leading biomedical engineers and aims at showing how the convergence of scientific and engineering fields with medicine has created a new basis for practically solving problems concerning human health, wellbeing and disease. While some of the latest frontiers of biomedicine, such as neuroscience and regenerative medicine, are becoming increasingly dependent on new ideas and tools from other disciplines, the paradigm shift caused by technological innovations in the fields of information science, nanotechnology, and robotics is opening new opportunities in healthcare, besides dramatically changing the ways we actually practice science. At the same time, a new generation of engineers, fluent in many different scientific “languages,” is creating entirely new fields of research that approach the “old” questions f...

  12. TECHNOLOGICAL CONVERGENCE AND THE NEW JOURNALIST

    Directory of Open Access Journals (Sweden)

    David Renault

    2013-12-01

    Full Text Available Beginning in the 1990s, Brazilian means of communication have experienced a (still ongoing transformation process in the treadmill of technological advances, which have allowed for broad media convergence and for a single journalistic group to offer diverse products across various digital platforms. These transformations have impacted profoundly the routines of journalistic newsrooms and their professionals, from whom more and more agility is expected in order to meet the demands of the new era. This study seeks to demonstrate how the new reality affects the routines of newsrooms and journalists at the Brasilia offices of four of the most prominent newspaper groups in the country: O Estado de S. Paulo, Folha de S. Paulo, Valor Econômico and O Globo.

  13. Converging intracranial markers of conscious access.

    Directory of Open Access Journals (Sweden)

    Raphaël Gaillard

    2009-03-01

    Full Text Available We compared conscious and nonconscious processing of briefly flashed words using a visual masking procedure while recording intracranial electroencephalogram (iEEG in ten patients. Nonconscious processing of masked words was observed in multiple cortical areas, mostly within an early time window (<300 ms, accompanied by induced gamma-band activity, but without coherent long-distance neural activity, suggesting a quickly dissipating feedforward wave. In contrast, conscious processing of unmasked words was characterized by the convergence of four distinct neurophysiological markers: sustained voltage changes, particularly in prefrontal cortex, large increases in spectral power in the gamma band, increases in long-distance phase synchrony in the beta range, and increases in long-range Granger causality. We argue that all of those measures provide distinct windows into the same distributed state of conscious processing. These results have a direct impact on current theoretical discussions concerning the neural correlates of conscious access.

  14. Exploring Media Convergence: Evidence from Italy

    Directory of Open Access Journals (Sweden)

    Debora Bettiga

    2013-12-01

    Full Text Available The evolution of media and devices is enabling the ubiquitous and multi-device access to media and information, so that a media mutual contamination is in play. New forms of user interactions with media, in which different devices are used simultaneously in different contexts, have emerged. These new interactions are significantly impacting on users’ attitudes towards the media and their way of searching and generating content. Such a change, called “media convergence”, has a strong potential impact on marketing and communication processes, but as yet has not been deeply analysed in the literature. This paper presents the outcomes of several studies aimed at exploring media convergence on the demand-side to advance possible implications for marketers and managers.

  15. Cylindrically converging blast waves in air

    Science.gov (United States)

    Matsuo, H.; Nakamura, Y.

    1981-07-01

    Cylindrically converging shock waves are produced by utilizing the detonation of cylindrical explosive shells. The production and the propagation of shock waves are observed by framing and streak camera photographs, and the trajectory of shock propagations is determined by using an electrical ionization probing system. The effect of the quantity of explosives on the stability, or the axial symmetry, of shock fronts and on the strength of shocks produced is investigated. It has been shown that, for practical purposes, the approximation of shock trajectories by Guderley's formulas would be sufficiently acceptable in an unexpectedly wide region near the implosion center, and that the axial symmetry of the shock front is improved by increasing the quantity of explosives, and thus, strong shocks are produced by merely increasing the quantity of explosives. The reflected diverging shock seems to be very stable. Piezoelectric elements have also been used to detect reflected diverging waves.

  16. Bricolage and Parody in Convergence culture

    Directory of Open Access Journals (Sweden)

    Javier MORAL MARTÍN

    2017-06-01

    Full Text Available In Convergence culture, collaborative practices have been commonly understood as exercises located between the amateur and the professional. This characterization involves an implicit underestimation of amateurism because, in a single organization hierarchy, is considered as a preliminary step to the professional world and, therefore, a more imperfect activity. However, if we draw on the categories of bricolage analyzed by Levi Strauss, amateurism and professionalism are constituted as elements of a semantic axis. This shift in the analysis perspective has important consequences: on the one hand, it makes it possible to assess how many of these practices can alter the productive and textual dynamics of professional audiovisual practices and, on the other hand, it helps to better understand the textual specificity of collaborative practices, especially the great dialogical category of parody, an essential genre in the bottom-up dynamics which exist in our audiovisual universe.

  17. Current neutralization of converging ion beams

    International Nuclear Information System (INIS)

    Mosher, D.

    1978-01-01

    It is desired to consider the problem of current neutralization of heavy ion beams traversing gas backgrounds in which the conductivity changes due to beam heating and beam convergence. The procedure is to determine Green's-function solutions to the magnetic-diffusion equation derived from Maxwell's equations and an assumed scaler-plasma conductivity sigma for the background-electron current density j/sub e/. The present calculation is more general than some previously carried out in that arbitrary time variations for the beam current j/sub b/ and conductivity are allowed and the calculation is valid for both weak and strong neutralization. Results presented here must be combined with an appropriate energy-balance equation for the heated background in order to obtain the neutralization self-consistently

  18. Rapidly converging path integral formalism. Pt. 1

    International Nuclear Information System (INIS)

    Bender, I.; Gromes, D.; Marquard, U.

    1990-01-01

    The action to be used in the path integral formalism is expanded in a systematic way in powers of the time spacing ε in order to optimize the convergence to the continuum limit. This modifies and extends the usual formalism in a transparent way. The path integral approximation to the Green function obtained by this method approaches the continuum Green function with a higher power of ε than the usual one. The general theoretical derivations are exemplified analytically for the harmonic oscillator and by Monte Carlo methods for the anharmonic oscillator. We also show how curvilinear coordinates and curved spaces can naturally be treated within this formalism. Work on field theory is in progress. (orig.)

  19. Divergence and Convergence in Education and Work

    DEFF Research Database (Denmark)

    of institutions the central issue concerns the relation between learning environments. What is the coherence between school-based education and learning in the work-place, and how can they connect? Finally at the third level of the learners and their identities the focus is on the role of vocational educational......Are the educational systems in Europe becoming more similar or more different? This book deals with the issue ofdivergence and convergence in relation to systems, learning environments, and learners in vocational educational training (VET). 18 VET researchers from eight countries contribute...... training in the formation of biographies and identities.The book thus covers the central issues on the agenda in relation to future vocational education....

  20. Convergence and fluctuations of Regularized Tyler estimators

    KAUST Repository

    Kammoun, Abla; Couillet, Romain; Pascal, Frederic; Alouini, Mohamed-Slim

    2015-01-01

    This article studies the behavior of regularized Tyler estimators (RTEs) of scatter matrices. The key advantages of these estimators are twofold. First, they guarantee by construction a good conditioning of the estimate and second, being a derivative of robust Tyler estimators, they inherit their robustness properties, notably their resilience to the presence of outliers. Nevertheless, one major problem that poses the use of RTEs in practice is represented by the question of setting the regularization parameter p. While a high value of p is likely to push all the eigenvalues away from zero, it comes at the cost of a larger bias with respect to the population covariance matrix. A deep understanding of the statistics of RTEs is essential to come up with appropriate choices for the regularization parameter. This is not an easy task and might be out of reach, unless one considers asymptotic regimes wherein the number of observations n and/or their size N increase together. First asymptotic results have recently been obtained under the assumption that N and n are large and commensurable. Interestingly, no results concerning the regime of n going to infinity with N fixed exist, even though the investigation of this assumption has usually predated the analysis of the most difficult N and n large case. This motivates our work. In particular, we prove in the present paper that the RTEs converge to a deterministic matrix when n → ∞ with N fixed, which is expressed as a function of the theoretical covariance matrix. We also derive the fluctuations of the RTEs around this deterministic matrix and establish that these fluctuations converge in distribution to a multivariate Gaussian distribution with zero mean and a covariance depending on the population covariance and the parameter.

  1. Cooperative target convergence using multiple agents

    International Nuclear Information System (INIS)

    Kwok, K.S.; Driessen, B.J.

    1997-01-01

    This work considers the problem of causing multiple (100''s) autonomous mobile robots to converge to a target and provides a follow-the-leader approach to the problem. Each robot has only a limited-range sensor for sending the target and also larger but also limited-range robot-to-robot communication capability. Because of the small amount of information available to the robots, a practical approach to improve convergence to the target is to have a robot follow the robot with the best quality of information. Specifically, each robot emits a signal that informs in-range robots what its status is. A robot has a status value of 0 if it is itself in range of the target. A robot has a status of 1 if it is not in range of the target but is in communication range of a robot that is in range of the target. A robot has a status of 2 if it is not in range of the target but is within range of another robot that has status 1, and so on. Of all the mobile robots that any given robot is in range of, it follows the one with the best status. The emergent behavior is the ant-like trails of robots following each other toward the target. If the robot is not in range of another robot that is either in range of the target or following another robot, the robot will assign-1 to its quality-of-information, and will execute an exhaustive search. The exhaustive search will continue until it encounters either the target or another robot with a nonnegative quality-of-information. The quality of information approach was extended to the case where each robot only has two-bit signals informing it of distance to in-range robots

  2. Convergence and fluctuations of Regularized Tyler estimators

    KAUST Repository

    Kammoun, Abla

    2015-10-26

    This article studies the behavior of regularized Tyler estimators (RTEs) of scatter matrices. The key advantages of these estimators are twofold. First, they guarantee by construction a good conditioning of the estimate and second, being a derivative of robust Tyler estimators, they inherit their robustness properties, notably their resilience to the presence of outliers. Nevertheless, one major problem that poses the use of RTEs in practice is represented by the question of setting the regularization parameter p. While a high value of p is likely to push all the eigenvalues away from zero, it comes at the cost of a larger bias with respect to the population covariance matrix. A deep understanding of the statistics of RTEs is essential to come up with appropriate choices for the regularization parameter. This is not an easy task and might be out of reach, unless one considers asymptotic regimes wherein the number of observations n and/or their size N increase together. First asymptotic results have recently been obtained under the assumption that N and n are large and commensurable. Interestingly, no results concerning the regime of n going to infinity with N fixed exist, even though the investigation of this assumption has usually predated the analysis of the most difficult N and n large case. This motivates our work. In particular, we prove in the present paper that the RTEs converge to a deterministic matrix when n → ∞ with N fixed, which is expressed as a function of the theoretical covariance matrix. We also derive the fluctuations of the RTEs around this deterministic matrix and establish that these fluctuations converge in distribution to a multivariate Gaussian distribution with zero mean and a covariance depending on the population covariance and the parameter.

  3. Origins of saline fluids at convergent margins

    Science.gov (United States)

    Martin, Jonathan B.; Kastner, Miriam; Egeberg, Per Kr.

    The compositions of pore and venting fluids at convergent margins differ from seawater values, reflecting mixing and diagenesis. Most significantly, the concentration of Cl-, assumed to be a conservative ion, differs from its seawater value. Chloride concentrations could be elevated by four processes, although two, the formation of gas hydrate and ion filtration by clay membranes, are insignificant in forming saline fluids at convergent margins. During the formation of gas hydrate, the resulting Cl--rich fluids, estimated to contain an average excess of ˜140 mM Cl- over seawater value, probably would be flushed from the sediment when the pore fluids vent to seawater. Ion filtration by clay membranes requires compaction pressures typical of >2 km burial depths. Even at these depths, the efficiency of ion filtration will be negligible because (1) fluids will flow through fractures, thereby bypassing clay membranes, (2) concentrations of clay minerals are diluted by other phases, and (3) during burial, smectite converts to illite, which has little capacity for ion filtration. A third process, mixing with subaerially evaporated seawater, elevates Cl- concentrations to 1043 mM in forearc basins along the Peru margin. Evaporation of seawater, however, will be important only in limited geographic regions that are characterized by enclosed basins, arid climates, and permeable sediments. At the New Hebrides and Izu-Bonin margins, Cl- concentrations are elevated to a maximum of 1241 mM. The process responsible for this increase is the alteration of volcanic ash to hydrous clay and zeolite minerals. Mass balance calculations, based on the decrease in δ18O values to -9.5‰ (SMOW), suggest that the Cl- concentrations could increase solely from the formation of smectite in a closed system. The diagenesis of volcanic ash also alters the concentrations of most dissolved species in addition to Cl-. Depending on the volume of this altered fluid, it could influence seawater

  4. Cooperative target convergence using multiple agents

    Energy Technology Data Exchange (ETDEWEB)

    Kwok, K.S.; Driessen, B.J.

    1997-10-01

    This work considers the problem of causing multiple (100`s) autonomous mobile robots to converge to a target and provides a follow-the-leader approach to the problem. Each robot has only a limited-range sensor for sending the target and also larger but also limited-range robot-to-robot communication capability. Because of the small amount of information available to the robots, a practical approach to improve convergence to the target is to have a robot follow the robot with the best quality of information. Specifically, each robot emits a signal that informs in-range robots what its status is. A robot has a status value of 0 if it is itself in range of the target. A robot has a status of 1 if it is not in range of the target but is in communication range of a robot that is in range of the target. A robot has a status of 2 if it is not in range of the target but is within range of another robot that has status 1, and so on. Of all the mobile robots that any given robot is in range of, it follows the one with the best status. The emergent behavior is the ant-like trails of robots following each other toward the target. If the robot is not in range of another robot that is either in range of the target or following another robot, the robot will assign-1 to its quality-of-information, and will execute an exhaustive search. The exhaustive search will continue until it encounters either the target or another robot with a nonnegative quality-of-information. The quality of information approach was extended to the case where each robot only has two-bit signals informing it of distance to in-range robots.

  5. Statistical convergence of double sequences in intuitionistic fuzzy normed spaces

    International Nuclear Information System (INIS)

    Mursaleen, M.; Mohiuddine, S.A.

    2009-01-01

    Recently, the concept of intuitionistic fuzzy normed spaces was introduced by Saadati and Park [Saadati R, Park JH. Chaos, Solitons and Fractals 2006;27:331-44]. Karakus et al. [Karakus S, Demirci K, Duman O. Chaos, Solitons and Fractals 2008;35:763-69] have quite recently studied the notion of statistical convergence for single sequences in intuitionistic fuzzy normed spaces. In this paper, we study the concept of statistically convergent and statistically Cauchy double sequences in intuitionistic fuzzy normed spaces. Furthermore, we construct an example of a double sequence to show that in IFNS statistical convergence does not imply convergence and our method of convergence even for double sequences is stronger than the usual convergence in intuitionistic fuzzy normed space.

  6. Convergence testing for MCNP5 Monte Carlo eigenvalue calculations

    International Nuclear Information System (INIS)

    Brown, F.; Nease, B.; Cheatham, J.

    2007-01-01

    Determining convergence of Monte Carlo criticality problems is complicated by the statistical noise inherent in the random, walks of the neutrons in each generation. The latest version of MCNP5 incorporates an important new tool for assessing convergence: the Shannon entropy of the fission source distribution, H src . Shannon entropy is a well-known concept from information theory and provides a single number for each iteration to help characterize convergence trends for the fission source distribution. MCNP5 computes H src for each iteration, and these values may be plotted to examine convergence trends. Convergence testing should include both k eff and H src , since the fission distribution will converge more slowly than k eff , especially when the dominance ratio is close to 1.0. (authors)

  7. Fourier convergence analysis applied to neutron diffusion Eigenvalue problem

    International Nuclear Information System (INIS)

    Lee, Hyun Chul; Noh, Jae Man; Joo, Hyung Kook

    2004-01-01

    Fourier error analysis has been a standard technique for the stability and convergence analysis of linear and nonlinear iterative methods. Though the methods can be applied to Eigenvalue problems too, all the Fourier convergence analyses have been performed only for fixed source problems and a Fourier convergence analysis for Eigenvalue problem has never been reported. Lee et al proposed new 2-D/1-D coupling methods and they showed that the new ones are unconditionally stable while one of the two existing ones is unstable at a small mesh size and that the new ones are better than the existing ones in terms of the convergence rate. In this paper the convergence of method A in reference 4 for the diffusion Eigenvalue problem was analyzed by the Fourier analysis. The Fourier convergence analysis presented in this paper is the first one applied to a neutronics eigenvalue problem to the best of our knowledge

  8. Work zone safety analysis.

    Science.gov (United States)

    2013-11-01

    This report presents research performed analyzing crashes in work zones in the state of New Jersey so as to : identify critical areas in work zones susceptible to crashes and key factors that contribute to these crashes. A field : data collection on ...

  9. Fault zone hydrogeology

    Science.gov (United States)

    Bense, V. F.; Gleeson, T.; Loveless, S. E.; Bour, O.; Scibek, J.

    2013-12-01

    Deformation along faults in the shallow crust (research effort of structural geologists and hydrogeologists. However, we find that these disciplines often use different methods with little interaction between them. In this review, we document the current multi-disciplinary understanding of fault zone hydrogeology. We discuss surface- and subsurface observations from diverse rock types from unlithified and lithified clastic sediments through to carbonate, crystalline, and volcanic rocks. For each rock type, we evaluate geological deformation mechanisms, hydrogeologic observations and conceptual models of fault zone hydrogeology. Outcrop observations indicate that fault zones commonly have a permeability structure suggesting they should act as complex conduit-barrier systems in which along-fault flow is encouraged and across-fault flow is impeded. Hydrogeological observations of fault zones reported in the literature show a broad qualitative agreement with outcrop-based conceptual models of fault zone hydrogeology. Nevertheless, the specific impact of a particular fault permeability structure on fault zone hydrogeology can only be assessed when the hydrogeological context of the fault zone is considered and not from outcrop observations alone. To gain a more integrated, comprehensive understanding of fault zone hydrogeology, we foresee numerous synergistic opportunities and challenges for the discipline of structural geology and hydrogeology to co-evolve and address remaining challenges by co-locating study areas, sharing approaches and fusing data, developing conceptual models from hydrogeologic data, numerical modeling, and training interdisciplinary scientists.

  10. Research proposal: Industry convergence - Driving forces, factors and consequences

    OpenAIRE

    Weaver, Benjamin

    2007-01-01

    Industry convergence – the merger of hitherto separate industries – is a phenomenon that has had a profound effect on several industries and received considerable interest among practitioners and business press over the past decades. Despite this, industry con- vergence has only received limited attention from the academic management field, al- though an emergent discussion on convergence can be identified. Prior research is limited by a lack of coherent theoretical definitions of convergence...

  11. Disparity and convergence: Chinese provincial government health expenditures.

    Science.gov (United States)

    Pan, Jay; Wang, Peng; Qin, Xuezheng; Zhang, Shufang

    2013-01-01

    The huge regional disparity in government health expenditures (GHE) is a major policy concern in China. This paper addresses whether provincial GHE converges in China from 1997 to 2009 using the economic convergence framework based on neoclassical economic growth theory. Our empirical investigation provides compelling evidence of long-term convergence in provincial GHE within China, but not in short-term. Policy implications of these empirical results are discussed.

  12. Disparity and convergence: Chinese provincial government health expenditures.

    Directory of Open Access Journals (Sweden)

    Jay Pan

    Full Text Available The huge regional disparity in government health expenditures (GHE is a major policy concern in China. This paper addresses whether provincial GHE converges in China from 1997 to 2009 using the economic convergence framework based on neoclassical economic growth theory. Our empirical investigation provides compelling evidence of long-term convergence in provincial GHE within China, but not in short-term. Policy implications of these empirical results are discussed.

  13. Monetary policy rules for convergence to the Euro

    OpenAIRE

    Orlowski, Lucjan T.

    2008-01-01

    This paper aims to devise a monetary policy instrument rule that is suitable for open economies undergoing monetary convergence to a common currency area. The open-economy convergence-consistent Taylor rule is forward-looking, consistent with monetary framework based on inflation targeting, containing input variables that are relative to the corresponding variables in the common currency area. The policy rule is tested empirically for three inflation targeting countries converging to the euro...

  14. Geometric convergence of some two-point Pade approximations

    International Nuclear Information System (INIS)

    Nemeth, G.

    1983-01-01

    The geometric convergences of some two-point Pade approximations are investigated on the real positive axis and on certain infinite sets of the complex plane. Some theorems concerning the geometric convergence of Pade approximations are proved, and bounds on geometric convergence rates are given. The results may be interesting considering the applications both in numerical computations and in approximation theory. As a specific case, the numerical calculations connected with the plasma dispersion function may be performed. (D.Gy.)

  15. Growth Convergence and Spending Efficiency among Filipino Households

    OpenAIRE

    Erniel B. Barrios

    2007-01-01

    A growth model is used in the context of Sala-i-Martin’s definition of conditional convergence to assess the household income dynamics in segmented groups at the provincial level in the Philippines. There is a direct relationship between spending efficiency and income growth convergence across income groups. The lower income convergence rate among low income households can be attributed to their relatively less efficient access to the factors of production. The study provides tools in identif...

  16. On the convergence of nonconvex minimization methods for image recovery.

    Science.gov (United States)

    Xiao, Jin; Ng, Michael Kwok-Po; Yang, Yu-Fei

    2015-05-01

    Nonconvex nonsmooth regularization method has been shown to be effective for restoring images with neat edges. Fast alternating minimization schemes have also been proposed and developed to solve the nonconvex nonsmooth minimization problem. The main contribution of this paper is to show the convergence of these alternating minimization schemes, based on the Kurdyka-Łojasiewicz property. In particular, we show that the iterates generated by the alternating minimization scheme, converges to a critical point of this nonconvex nonsmooth objective function. We also extend the analysis to nonconvex nonsmooth regularization model with box constraints, and obtain similar convergence results of the related minimization algorithm. Numerical examples are given to illustrate our convergence analysis.

  17. Institutional and Socio-Economic Convergence in the European Union

    Directory of Open Access Journals (Sweden)

    Jordi López-Tamayo

    2014-12-01

    Full Text Available The objective of this paper is to analyze convergence in institutional, social, and macroeconomic conditions between EU member states. Our analysis covers the period 1995-2013 and considers the potential impact of the Great Recession. With this aim, we use a composite indicator that combines information from 51 hard and soft indicators, and we estimate convergence equations for the composite indicator and its seven dimensions considering different country groups. The obtained results show evidence of conditional convergence among EU member states but limited evidence of unconditional convergence over the considered period.

  18. Text experiments of disk chopper with supermirror converging system

    International Nuclear Information System (INIS)

    Aizawa, K.; Soyama, K.; Matsubayashi, M.; Suzuki, J.; Watanabe, N.

    2001-01-01

    We measured transportation property of neutron pulsed by disk chopper with three kinds of setting of supermirror guide at JRR-3M, JAERI. We confirmed a gain of supermirror converging system to narrow straight supermirror system. The gain is approximately same as the ratio of entrance width of converging guide to width of narrow straight guide. On the other hand, we did not get a gain of supermirror converging system to wide straight supermirror system which has a same width to entrance width of converging guide and we will plan more precisely experiment. (author)

  19. Convergence Performance of Adaptive Algorithms of L-Filters

    Directory of Open Access Journals (Sweden)

    Robert Hudec

    2003-01-01

    Full Text Available This paper deals with convergence parameters determination of adaptive algorithms, which are used in adaptive L-filters design. Firstly the stability of adaptation process, convergence rate or adaptation time, and behaviour of convergence curve belong among basic properties of adaptive algorithms. L-filters with variety of adaptive algorithms were used to their determination. Convergence performances finding of adaptive filters is important mainly for their hardware applications, where filtration in real time or adaptation of coefficient filter with low capacity of input data are required.

  20. Fractal aspects and convergence of Newton`s method

    Energy Technology Data Exchange (ETDEWEB)

    Drexler, M. [Oxford Univ. Computing Lab. (United Kingdom)

    1996-12-31

    Newton`s Method is a widely established iterative algorithm for solving non-linear systems. Its appeal lies in its great simplicity, easy generalization to multiple dimensions and a quadratic local convergence rate. Despite these features, little is known about its global behavior. In this paper, we will explain a seemingly random global convergence pattern using fractal concepts and show that the behavior of the residual is entirely explicable. We will also establish quantitative results for the convergence rates. Knowing the mechanism of fractal generation, we present a stabilization to the orthodox Newton method that remedies the fractal behavior and improves convergence.

  1. Strong convergence and convergence rates of approximating solutions for algebraic Riccati equations in Hilbert spaces

    Science.gov (United States)

    Ito, Kazufumi

    1987-01-01

    The linear quadratic optimal control problem on infinite time interval for linear time-invariant systems defined on Hilbert spaces is considered. The optimal control is given by a feedback form in terms of solution pi to the associated algebraic Riccati equation (ARE). A Ritz type approximation is used to obtain a sequence pi sup N of finite dimensional approximations of the solution to ARE. A sufficient condition that shows pi sup N converges strongly to pi is obtained. Under this condition, a formula is derived which can be used to obtain a rate of convergence of pi sup N to pi. The results of the Galerkin approximation is demonstrated and applied for parabolic systems and the averaging approximation for hereditary differential systems.

  2. Convergence accommodation to convergence (CA/C) ratio in patients with intermittent exotropia and decompensated exophoria.

    Science.gov (United States)

    Nonaka, Fumitaka; Hasebe, Satoshi; Ohtsuki, Hiroshi

    2004-01-01

    To evaluate the convergence accommodation to convergence (CA/C) ratio in strabismic patients and to clarify its clinical implications. Seventy-eight consecutive patients (mean age: 12.9 +/- 6.0 years) with intermittent exotropia and decompensated exophoria who showed binocular fusion at least at near viewing were recruited. The CA/C ratio was estimated by measuring accommodative responses induced by horizontal prisms with different magnitudes under accommodation feedback open-loop conditions. The CA/C ratios were compared with accommodative convergence to accommodation (AC/A) ratios and other clinical parameters. A linear regression analysis indicated that the mean (+/-SD) CA/C ratio was 0.080 +/- 0.043 D/prism diopter or 0.48 +/- 0.26 D/meter angle. There was no inverse or reciprocal relationship between CA/C and AC/A ratios. The patients with lower CA/C ratios tended to have smaller tonic accommodation under binocular viewing conditions and larger exodeviation at near viewing. The CA/C ratio, like the AC/A ratio, is an independent parameter that characterizes clinical features. A lower CA/C may be beneficial for the vergence control system to compensate for ocular misalignment with minimum degradation of accommodation accuracy.

  3. TESTING CONVERGENCE FOR GLOBAL ACCRETION DISKS

    Energy Technology Data Exchange (ETDEWEB)

    Hawley, John F.; Richers, Sherwood A.; Guan Xiaoyue [Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904-4325 (United States); Krolik, Julian H., E-mail: jh8h@virginia.edu, E-mail: xg3z@virginia.edu, E-mail: jhk@pha.jhu.edu [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218 (United States)

    2013-08-01

    Global disk simulations provide a powerful tool for investigating accretion and the underlying magnetohydrodynamic turbulence driven by magneto-rotational instability (MRI). Using them to accurately predict quantities such as stress, accretion rate, and surface brightness profile requires that purely numerical effects, arising from both resolution and algorithm, be understood and controlled. We use the flux-conservative Athena code to conduct a series of experiments on disks having a variety of magnetic topologies to determine what constitutes adequate resolution. We develop and apply several resolution metrics: (Q{sub z} ) and (Q{sub {phi}}), the ratio of the grid zone size to the characteristic MRI wavelength, {alpha}{sub mag}, the ratio of the Maxwell stress to the magnetic pressure, and /, the ratio of radial to toroidal magnetic field energy. For the initial conditions considered here, adequate resolution is characterized by (Q{sub z} ) {>=} 15, (Q{sub {phi}}) {>=} 20, {alpha}{sub mag} Almost-Equal-To 0.45, and /{approx}0.2. These values are associated with {>=}35 zones per scaleheight H, a result consistent with shearing box simulations. Numerical algorithm is also important. Use of the Harten-Lax-van Leer-Einfeldt flux solver or second-order interpolation can significantly degrade the effective resolution compared to the Harten-Lax-van Leer discontinuities flux solver and third-order interpolation. Resolution at this standard can be achieved only with large numbers of grid zones, arranged in a fashion that matches the symmetries of the problem and the scientific goals of the simulation. Without it, however, quantitative measures important to predictions of observables are subject to large systematic errors.

  4. Converging cylindrical shocks in ideal magnetohydrodynamics

    International Nuclear Information System (INIS)

    Pullin, D. I.; Mostert, W.; Wheatley, V.; Samtaney, R.

    2014-01-01

    We consider a cylindrically symmetrical shock converging onto an axis within the framework of ideal, compressible-gas non-dissipative magnetohydrodynamics (MHD). In cylindrical polar co-ordinates we restrict attention to either constant axial magnetic field or to the azimuthal but singular magnetic field produced by a line current on the axis. Under the constraint of zero normal magnetic field and zero tangential fluid speed at the shock, a set of restricted shock-jump conditions are obtained as functions of the shock Mach number, defined as the ratio of the local shock speed to the unique magnetohydrodynamic wave speed ahead of the shock, and also of a parameter measuring the local strength of the magnetic field. For the line current case, two approaches are explored and the results compared in detail. The first is geometrical shock-dynamics where the restricted shock-jump conditions are applied directly to the equation on the characteristic entering the shock from behind. This gives an ordinary-differential equation for the shock Mach number as a function of radius which is integrated numerically to provide profiles of the shock implosion. Also, analytic, asymptotic results are obtained for the shock trajectory at small radius. The second approach is direct numerical solution of the radially symmetric MHD equations using a shock-capturing method. For the axial magnetic field case the shock implosion is of the Guderley power-law type with exponent that is not affected by the presence of a finite magnetic field. For the axial current case, however, the presence of a tangential magnetic field ahead of the shock with strength inversely proportional to radius introduces a length scale R=√(μ 0 /p 0 ) I/(2 π) where I is the current, μ 0 is the permeability, and p 0 is the pressure ahead of the shock. For shocks initiated at r ≫ R, shock convergence is first accompanied by shock strengthening as for the strictly gas-dynamic implosion. The diverging magnetic field

  5. Converging cylindrical shocks in ideal magnetohydrodynamics

    KAUST Repository

    Pullin, D. I.

    2014-09-01

    We consider a cylindrically symmetrical shock converging onto an axis within the framework of ideal, compressible-gas non-dissipative magnetohydrodynamics (MHD). In cylindrical polar co-ordinates we restrict attention to either constant axial magnetic field or to the azimuthal but singular magnetic field produced by a line current on the axis. Under the constraint of zero normal magnetic field and zero tangential fluid speed at the shock, a set of restricted shock-jump conditions are obtained as functions of the shock Mach number, defined as the ratio of the local shock speed to the unique magnetohydrodynamic wave speed ahead of the shock, and also of a parameter measuring the local strength of the magnetic field. For the line current case, two approaches are explored and the results compared in detail. The first is geometrical shock-dynamics where the restricted shock-jump conditions are applied directly to the equation on the characteristic entering the shock from behind. This gives an ordinary-differential equation for the shock Mach number as a function of radius which is integrated numerically to provide profiles of the shock implosion. Also, analytic, asymptotic results are obtained for the shock trajectory at small radius. The second approach is direct numerical solution of the radially symmetric MHD equations using a shock-capturing method. For the axial magnetic field case the shock implosion is of the Guderley power-law type with exponent that is not affected by the presence of a finite magnetic field. For the axial current case, however, the presence of a tangential magnetic field ahead of the shock with strength inversely proportional to radius introduces a length scale R = √μ0/p0 I/(2π) where I is the current, μ0 is the permeability, and p0 is the pressure ahead of the shock. For shocks initiated at r ≫ R, shock convergence is first accompanied by shock strengthening as for the strictly gas-dynamic implosion. The diverging magnetic field then

  6. A convergent reformulation of perturbative QCD

    International Nuclear Information System (INIS)

    Alves, R.J.G.

    2000-10-01

    We present and explore a new formulation of perturbative QCD based not on the renormalised coupling but on the dimensional transmutation parameter of the theory and the property of asymptotic scaling. The approach yields a continued function, the iterated function being that involved in the solution of the two-loop β-function equation. In the so-called large-b limit the continued function reduces to a continued fraction and the successive approximants are diagonal Pade approximants. We investigate numerically the convergence of successive approximants using the leading-b approximation, motivated by renormalons, to model the all-orders result. We consider the Adler D-function of vacuum polarisation, the Polarised Bjorken and Gross-LIewellyn Smith sum rules, the (unpolarised) Bjorken sum rule, and the Minkowskian quantities R τ and the R-ratio of e + e - annihilation. In contrast to diagonal Pade approximants the truncated continued function method gives remarkably stable large-order approximants in cases where infrared renormalon effects are important. We also use the new approach to determine the QCD fundamental parameters from the R τ and the R-ratio measurements, where we find Λ-tilde (3)/MS = 516 ± 48 MeV (which yields α s (μ = m τ ) = 0.360 -0.020 +0.021 ), and Λ-tilde (5)/MS = 299 -7 +6 MeV (which yields α s (μ = m z 0 ) = 0.1218 ± 0.0004), respectively. The evolution of the former value to the m z 0 energy results in α s (μ = m z 0 ) = 0.123 ± 0.002. These values are in line with other determinations available in the literature. We implement the Complete Renormalisation Group Improvement (CORGI) scheme throughout all the calculations. We report on how the mathematical concept of Stieltjes series can be used to assess the convergence of Pade approximants of perturbative series. We find that the combinations of UV renormalons which occur in perturbative QCD may or may not be Stieltjes series depending on the renormalisation scheme used. (author)

  7. Converging cylindrical shocks in ideal magnetohydrodynamics

    KAUST Repository

    Pullin, D. I.; Mostert, W.; Wheatley, V.; Samtaney, Ravi

    2014-01-01

    We consider a cylindrically symmetrical shock converging onto an axis within the framework of ideal, compressible-gas non-dissipative magnetohydrodynamics (MHD). In cylindrical polar co-ordinates we restrict attention to either constant axial magnetic field or to the azimuthal but singular magnetic field produced by a line current on the axis. Under the constraint of zero normal magnetic field and zero tangential fluid speed at the shock, a set of restricted shock-jump conditions are obtained as functions of the shock Mach number, defined as the ratio of the local shock speed to the unique magnetohydrodynamic wave speed ahead of the shock, and also of a parameter measuring the local strength of the magnetic field. For the line current case, two approaches are explored and the results compared in detail. The first is geometrical shock-dynamics where the restricted shock-jump conditions are applied directly to the equation on the characteristic entering the shock from behind. This gives an ordinary-differential equation for the shock Mach number as a function of radius which is integrated numerically to provide profiles of the shock implosion. Also, analytic, asymptotic results are obtained for the shock trajectory at small radius. The second approach is direct numerical solution of the radially symmetric MHD equations using a shock-capturing method. For the axial magnetic field case the shock implosion is of the Guderley power-law type with exponent that is not affected by the presence of a finite magnetic field. For the axial current case, however, the presence of a tangential magnetic field ahead of the shock with strength inversely proportional to radius introduces a length scale R = √μ0/p0 I/(2π) where I is the current, μ0 is the permeability, and p0 is the pressure ahead of the shock. For shocks initiated at r ≫ R, shock convergence is first accompanied by shock strengthening as for the strictly gas-dynamic implosion. The diverging magnetic field then

  8. Converging cylindrical shocks in ideal magnetohydrodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Pullin, D. I. [Graduate Aerospace Laboratories, California Institute of Technology, Pasadena, California 91125 (United States); Mostert, W.; Wheatley, V. [School of Mechanical and Mining Engineering, University of Queensland, Queensland 4072 (Australia); Samtaney, R. [Mechanical Engineering, Physical Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal (Saudi Arabia)

    2014-09-15

    We consider a cylindrically symmetrical shock converging onto an axis within the framework of ideal, compressible-gas non-dissipative magnetohydrodynamics (MHD). In cylindrical polar co-ordinates we restrict attention to either constant axial magnetic field or to the azimuthal but singular magnetic field produced by a line current on the axis. Under the constraint of zero normal magnetic field and zero tangential fluid speed at the shock, a set of restricted shock-jump conditions are obtained as functions of the shock Mach number, defined as the ratio of the local shock speed to the unique magnetohydrodynamic wave speed ahead of the shock, and also of a parameter measuring the local strength of the magnetic field. For the line current case, two approaches are explored and the results compared in detail. The first is geometrical shock-dynamics where the restricted shock-jump conditions are applied directly to the equation on the characteristic entering the shock from behind. This gives an ordinary-differential equation for the shock Mach number as a function of radius which is integrated numerically to provide profiles of the shock implosion. Also, analytic, asymptotic results are obtained for the shock trajectory at small radius. The second approach is direct numerical solution of the radially symmetric MHD equations using a shock-capturing method. For the axial magnetic field case the shock implosion is of the Guderley power-law type with exponent that is not affected by the presence of a finite magnetic field. For the axial current case, however, the presence of a tangential magnetic field ahead of the shock with strength inversely proportional to radius introduces a length scale R=√(μ{sub 0}/p{sub 0}) I/(2 π) where I is the current, μ{sub 0} is the permeability, and p{sub 0} is the pressure ahead of the shock. For shocks initiated at r ≫ R, shock convergence is first accompanied by shock strengthening as for the strictly gas-dynamic implosion. The

  9. Convergence analysis in near-field imaging

    International Nuclear Information System (INIS)

    Bao, Gang; Li, Peijun

    2014-01-01

    This paper is devoted to the mathematical analysis of the direct and inverse modeling of the diffraction by a perfectly conducting grating surface in the near-field regime. It is motivated by our effort to analyze recent significant numerical results, in order to solve a class of inverse rough surface scattering problems in near-field imaging. In a model problem, the diffractive grating surface is assumed to be a small and smooth deformation of a plane surface. On the basis of the variational method, the direct problem is shown to have a unique weak solution. An analytical solution is introduced as a convergent power series in the deformation parameter by using the transformed field and Fourier series expansions. A local uniqueness result is proved for the inverse problem where only a single incident field is needed. On the basis of the analytic solution of the direct problem, an explicit reconstruction formula is presented for recovering the grating surface function with resolution beyond the Rayleigh criterion. Error estimates for the reconstructed grating surface are established with fully revealed dependence on such quantities as the surface deformation parameter, measurement distance, noise level of the scattering data, and regularity of the exact grating surface function. (paper)

  10. Value Creation Through Integrated Networks and Convergence

    Energy Technology Data Exchange (ETDEWEB)

    De Martini, Paul; Taft, Jeffrey D.

    2015-04-01

    Customer adoption of distributed energy resources and public policies are driving changes in the uses of the distribution system. A system originally designed and built for one-way energy flows from central generating facilities to end-use customers is now experiencing injections of energy from customers anywhere on the grid and frequent reversals in the direction of energy flow. In response, regulators and utilities are re-thinking the design and operations of the grid to create more open and transactive electric networks. This evolution has the opportunity to unlock significant value for customers and utilities. Alternatively, failure to seize this potential may instead lead to an erosion of value if customers seek to defect and disconnect from the system. This paper will discuss how current grid modernization investments may be leveraged to create open networks that increase value through the interaction of intelligent devices on the grid and prosumerization of customers. Moreover, even greater value can be realized through the synergistic effects of convergence of multiple networks. This paper will highlight examples of the emerging nexus of non-electric networks with electricity.

  11. 5G: The Convergence of Wireless Communications.

    Science.gov (United States)

    Chávez-Santiago, Raúl; Szydełko, Michał; Kliks, Adrian; Foukalas, Fotis; Haddad, Yoram; Nolan, Keith E; Kelly, Mark Y; Masonta, Moshe T; Balasingham, Ilangko

    As the rollout of 4G mobile communication networks takes place, representatives of industry and academia have started to look into the technological developments toward the next generation (5G). Several research projects involving key international mobile network operators, infrastructure manufacturers, and academic institutions, have been launched recently to set the technological foundations of 5G. However, the architecture of future 5G systems, their performance, and mobile services to be provided have not been clearly defined. In this paper, we put forth the vision for 5G as the convergence of evolved versions of current cellular networks with other complementary radio access technologies. Therefore, 5G may not be a single radio access interface but rather a "network of networks". Evidently, the seamless integration of a variety of air interfaces, protocols, and frequency bands, requires paradigm shifts in the way networks cooperate and complement each other to deliver data rates of several Gigabits per second with end-to-end latency of a few milliseconds. We provide an overview of the key radio technologies that will play a key role in the realization of this vision for the next generation of mobile communication networks. We also introduce some of the research challenges that need to be addressed.

  12. Convergence of Corporate and Public Governance

    Directory of Open Access Journals (Sweden)

    Gérard Hirigoyen

    2013-06-01

    Full Text Available By analyzing the differences between the corporate and public governance, theoretical and empirical research seems to indicate that the two domains of governance are far too different to share any common aspect. However, in this particular research, it has been argued that public governance is an application of corporate governance. Thus, the research question entails the description and analysis of this possible convergence of the two. Extensive research from literature on corporate governance has been undertaken to establish a relationship between the boards process and the roles that acts as a framework to bridge the gap separating corporate governance from public governance. Corporate governance, at a global level, exists in the for-profit as well as nonprofit organizations. Thus, the definition of this concept needs to be viewed from “an innovative” eye, considering the relationship between the process of the board and roles as characteristic of the public organization and private ones. As the private as well as public organizations are an application of corporate governance, the difference between the two gets narrowed. For the purpose of this research, the case of the French hospitals’ board has been taken into consideration. The members of the public board have been considered for the board process to perform their roles.

  13. East Asian Capital Markets: Integration and Convergence

    Directory of Open Access Journals (Sweden)

    Yana Valeryevna Dyomina

    2016-09-01

    Full Text Available The article examines the interdependence of East Asian stock and bond markets. Hierarchical cluster analysis of bond markets of ten regional countries shows that the most similar ones are the following: Indonesia, Malaysia, the Philippines and Singapore. In 2006-2009 Thailand also belonged with this group, however, since 2010 it is a separate cluster. The second cluster includes Hong Kong, the Republic of Korea and China, the third one - Japan, the fourth one - Vietnam. As for regional equity markets, the study shows that regional stock indices respond to the dynamics of American ones to a greater extent than to the dynamics of each other. In addition, Asian indices’ interconnection is chiefly negative. To assess stock indices’ convergence the author employs cluster analysis which divides 16 studied stock exchanges in 7 different groups. According to the obtained results, the author concludes that integration of regional capital markets is the long-term goal. Besides, markets’ integration will be easier and faster within clusters; inter-cluster mergers will be the next step. The basic problem here arises from the Japanese market, which, in the case of forced or ill-conceived program of events, will absorb all other markets or end up outside the integration processes

  14. Conformal mapping and convergence of Krylov iterations

    Energy Technology Data Exchange (ETDEWEB)

    Driscoll, T.A.; Trefethen, L.N. [Cornell Univ., Ithaca, NY (United States)

    1994-12-31

    Connections between conformal mapping and matrix iterations have been known for many years. The idea underlying these connections is as follows. Suppose the spectrum of a matrix or operator A is contained in a Jordan region E in the complex plane with 0 not an element of E. Let {phi}(z) denote a conformal map of the exterior of E onto the exterior of the unit disk, with {phi}{infinity} = {infinity}. Then 1/{vert_bar}{phi}(0){vert_bar} is an upper bound for the optimal asymptotic convergence factor of any Krylov subspace iteration. This idea can be made precise in various ways, depending on the matrix iterations, on whether A is finite or infinite dimensional, and on what bounds are assumed on the non-normality of A. This paper explores these connections for a variety of matrix examples, making use of a new MATLAB Schwarz-Christoffel Mapping Toolbox developed by the first author. Unlike the earlier Fortran Schwarz-Christoffel package SCPACK, the new toolbox computes exterior as well as interior Schwarz-Christoffel maps, making it easy to experiment with spectra that are not necessarily symmetric about an axis.

  15. VT Data - Zoning 20120709, Huntington

    Data.gov (United States)

    Vermont Center for Geographic Information — Zoning district data for the Town of Huntington, Vermont. For details regarding each zoning district refer to the current zoning regulations on town of Huntington's...

  16. Converging from branching to linear metrics on Markov chains

    DEFF Research Database (Denmark)

    Bacci, Giorgio; Bacci, Giovanni; Larsen, Kim G.

    2017-01-01

    -approximant is computable in polynomial time in the size of the MC. The upper-approximants are bisimilarity-like pseudometrics (hence, branching-time distances) that converge point-wise to the linear-time metrics. This convergence is interesting in itself, because it reveals a nontrivial relation between branching...

  17. Converging from Branching to Linear Metrics on Markov Chains

    DEFF Research Database (Denmark)

    Bacci, Giorgio; Bacci, Giovanni; Larsen, Kim Guldstrand

    2015-01-01

    time in the size of the MC. The upper-approximants are Kantorovich-like pseudometrics, i.e. branching-time distances, that converge point-wise to the linear-time metrics. This convergence is interesting in itself, since it reveals a nontrivial relation between branching and linear-time metric...

  18. On the convergence of linear passive complementarity systems

    NARCIS (Netherlands)

    Camlibel, M. Kanat; Wouw, Nathan van de

    2007-01-01

    The notion of convergent systems is a powerful tool both in the analysis and synthesis of nonlinear systems. Sufficient conditions for convergence have been under investigation for smooth systems and for classes of non-smooth switching systems in the literature. In this paper, we look at a very

  19. Confidence building on euro convergence : Evidence from currency options

    NARCIS (Netherlands)

    Driessen, J.J.A.G.; Perotti, E.

    2011-01-01

    We study the evolution of investor confidence in 1992–1998 over the chance of individual currencies to converge to the Euro, using data on currency option prices. Convergence risk, which may reflect uncertainty over policy commitment as well as exogenous fundamentals, induces a level of implied

  20. Confidence building on Euro convergence: evidence from currency options

    NARCIS (Netherlands)

    Driessen, J.; Perotti, E.

    2011-01-01

    We study the evolution of investor confidence in 1992-1998 over the chance of individual currencies to converge to the Euro, using data on currency option prices. Convergence risk, which may reflect uncertainty over policy commitment as well as exogenous fundamentals, induces a level of implied

  1. Presentation of Topic 1: Economic Convergence and Poverty ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    4 nov. 2010 ... Please find below in PDF format all submitted presentations during the first session on Tuesday 8 December : Economic Convergence and Poverty ReductionNote de cadrage (Scope of study):1 - Economic Convergence and Poverty Reduction – M. Diery SECK, Director of CREPOLScientific ...

  2. Thermal and mechanical modelling of convergent plate margins

    NARCIS (Netherlands)

    van den Beukel, P.J.

    1990-01-01

    In this thesis, the thermal and mechanical structure of convergent plate margins will be investigated by means of numerical modelling. In addition, we will discuss the implications of modelling results for geological processes such as metamorphism or the break-up of a plate at a convergent plate

  3. Measuring Convergence using Dynamic Equilibrium Models: Evidence from Chinese Provinces

    DEFF Research Database (Denmark)

    Pan, Lei; Posch, Olaf; van der Wel, Michel

    We propose a model to study economic convergence in the tradition of neoclassical growth theory. We employ a novel stochastic set-up of the Solow (1956) model with shocks to both capital and labor. Our novel approach identifies the speed of convergence directly from estimating the parameters which...

  4. Note: interpreting iterative methods convergence with diffusion point of view

    OpenAIRE

    Hong, Dohy

    2013-01-01

    In this paper, we explain the convergence speed of different iteration schemes with the fluid diffusion view when solving a linear fixed point problem. This interpretation allows one to better understand why power iteration or Jacobi iteration may converge faster or slower than Gauss-Seidel iteration.

  5. A survey of Strong Convergent Schemes for the Simulation of ...

    African Journals Online (AJOL)

    We considered strong convergent stochastic schemes for the simulation of stochastic differential equations. The stochastic Taylor's expansion, which is the main tool used for the derivation of strong convergent schemes; the Euler Maruyama, Milstein scheme, stochastic multistep schemes, Implicit and Explicit schemes were ...

  6. Moment Convergence Rates in the Law of the Logarithm for ...

    Indian Academy of Sciences (India)

    Home; Journals; Proceedings – Mathematical Sciences; Volume 119; Issue 3. Moment Convergence Rates in the Law of the Logarithm for Dependent Sequences. Ke-Ang Fu Xiao-Rong Yang ... Keywords. The law of the logarithm; Chung-type law of the logarithm; negative association; moment convergence; tail probability.

  7. Exponential convergence on a continuous Monte Carlo transport problem

    International Nuclear Information System (INIS)

    Booth, T.E.

    1997-01-01

    For more than a decade, it has been known that exponential convergence on discrete transport problems was possible using adaptive Monte Carlo techniques. An adaptive Monte Carlo method that empirically produces exponential convergence on a simple continuous transport problem is described

  8. Some New Lacunary Strong Convergent Vector-Valued Sequence Spaces

    Directory of Open Access Journals (Sweden)

    M. Mursaleen

    2014-01-01

    Full Text Available We introduce some vector-valued sequence spaces defined by a Musielak-Orlicz function and the concepts of lacunary convergence and strong (A-convergence, where A=(aik is an infinite matrix of complex numbers. We also make an effort to study some topological properties and some inclusion relations between these spaces.

  9. Some New Lacunary Strong Convergent Vector-Valued Sequence Spaces

    OpenAIRE

    Mursaleen, M.; Alotaibi, A.; Sharma, Sunil K.

    2014-01-01

    We introduce some vector-valued sequence spaces defined by a Musielak-Orlicz function and the concepts of lacunary convergence and strong ( $A$ )-convergence, where $A=({a}_{ik})$ is an infinite matrix of complex numbers. We also make an effort to study some topological properties and some inclusion relations between these spaces.

  10. Sigma-convergence of stationary Navier-Stokes type equations

    Directory of Open Access Journals (Sweden)

    Gabriel Nguetseng

    2009-06-01

    Full Text Available In the framework of homogenization theory, the Sigma-convergence method is carried out on stationary Navier-Stokes type equations on a fixed domain. Our main tools are the two-scale convergence concept and the so-called homogenization algebras.

  11. Ideal Convergence of k-Positive Linear Operators

    Directory of Open Access Journals (Sweden)

    Akif Gadjiev

    2012-01-01

    Full Text Available We study some ideal convergence results of k-positive linear operators defined on an appropriate subspace of the space of all analytic functions on a bounded simply connected domain in the complex plane. We also show that our approximation results with respect to ideal convergence are more general than the classical ones.

  12. Convergence of p-series revisited with applications

    Directory of Open Access Journals (Sweden)

    Elom K. Abalo

    2006-01-01

    Full Text Available We construct two adjacent sequences that converge to the sum of a given convergent p-series. In case of a divergent p-series, lower and upper bounds of the (knth partial sum are constructed. In either case, we extend the results obtained by Hansheng and Lu (2005 to any integer k≥2. Some numerical examples are given.

  13. On the premature convergence of particle swarm optimization

    DEFF Research Database (Denmark)

    Larsen, Rie B.; Jouffroy, Jerome; Lassen, Benny

    2016-01-01

    This paper discusses convergence issues of the basic particle swarm optimization algorithm for different pa- rameters. For the one-dimensional case, it is shown that, for a specific range of parameters, the particles will converge prematurely, i.e. away from the actual minimum of the objective...

  14. Convergence of Crowdsourcing Ideas: A Cognitive Load perspective

    DEFF Research Database (Denmark)

    Fu, Shixuan; de Vreede, Gert-Jan; Cheng, Xusen

    2017-01-01

    and satisfaction with the convergence process and outcomes. We propose an experimental study that adopts Cognitive Load Theory as its theoretical lens to investigate the effects of task complexity, idea presentation, and instructional guidance on convergence quality and satisfaction. This study has the potential...

  15. Vector-valued almost convergence and classical properties in ...

    Indian Academy of Sciences (India)

    So, Banach limits are legitimate extensions of the limit function on c. In. [14], Lorentz made use of the concept of Banach limit to introduce the notion of 'almost convergence'. DEFINITION 1.2 [14]. A bounded sequence (xn)n∈N ∈ l∞ is called almost convergent exactly when there exists a number y ∈ R (called the almost ...

  16. Strategic Vision on Convergence of Wired and Wireless Networks

    DEFF Research Database (Denmark)

    Prasad, Ramjee; Olsen, Rasmus Løvenstein; Saarnio, Juha

    2006-01-01

    In this paper we provide an overview of how convergence will play an important role in future generation networks. We discuss how the technology today will eventually converge towards an all-IP based platform, while the commonly used layered software structure, will eventually merge into a layer ...... aspect, namely security and privacy issues within future generationnetworks....

  17. Are codes fostering convergence in corporate governance? An institutional perspective

    NARCIS (Netherlands)

    Haxhi, I.; Aguilera, R.V.; Rasheed, A.A.; Yoshikawa, T.

    2012-01-01

    This chapter discusses the role of corporate governance codes in the context of pressures for corporate governance convergence across countries. We show that there is a diverging convergence as corporate governance practices continually evolve. Further, given that codes are non-mandatory in most

  18. Convergent evolution as natural experiment: the tape of life reconsidered.

    Science.gov (United States)

    Powell, Russell; Mariscal, Carlos

    2015-12-06

    Stephen Jay Gould argued that replaying the 'tape of life' would result in radically different evolutionary outcomes. Recently, biologists and philosophers of science have paid increasing attention to the theoretical importance of convergent evolution-the independent origination of similar biological forms and functions-which many interpret as evidence against Gould's thesis. In this paper, we examine the evidentiary relevance of convergent evolution for the radical contingency debate. We show that under the right conditions, episodes of convergent evolution can constitute valid natural experiments that support inferences regarding the deep counterfactual stability of macroevolutionary outcomes. However, we argue that proponents of convergence have problematically lumped causally heterogeneous phenomena into a single evidentiary basket, in effect treating all convergent events as if they are of equivalent theoretical import. As a result, the 'critique from convergent evolution' fails to engage with key claims of the radical contingency thesis. To remedy this, we develop ways to break down the heterogeneous set of convergent events based on the nature of the generalizations they support. Adopting this more nuanced approach to convergent evolution allows us to differentiate iterated evolutionary outcomes that are probably common among alternative evolutionary histories and subject to law-like generalizations, from those that do little to undermine and may even support, the Gouldian view of life.

  19. Productivity convergence and spatial dependence among Spanish regions

    NARCIS (Netherlands)

    Dall'erba, S.D.

    2005-01-01

    This paper estimates the evolution of labor productivity disparities among 48 Spanish regions over 1980-1996 according to the concepts of β- and σ-convergence. The results of β-convergence emphasize the importance of including the impact of neighboring locations' productivity and a disaggregate

  20. Promise Zones for Applicants

    Data.gov (United States)

    Department of Housing and Urban Development — This tool assists applicants to HUD's Promise Zone initiative prepare data to submit with their application by allowing applicants to draw the exact location of the...

  1. Speeds in school zones.

    Science.gov (United States)

    2009-02-01

    School speed zones are frequently requested traffic controls for school areas, based on the common belief : that if the transportation agency would only install a reduced speed limit, then drivers would no longer : speed through the area. This resear...

  2. Buffer Zone Fact Sheets

    Science.gov (United States)

    New requirements for buffer zones and sign posting contribute to soil fumigant mitigation and protection for workers and bystanders. The buffer provides distance between the pesticide application site and bystanders, reducing exposure risk.

  3. DRIVERS OF LONG-TERM CONVERGENCE. FOCUS ON ROMANIA

    Directory of Open Access Journals (Sweden)

    MANUELA UNGURU

    2014-11-01

    Full Text Available With initial low levels of income per capita, a declining population and relatively modest economic growth rates, there are little prospects of diminishing the gap between Romania and the EU countries. Nevertheless, in the long term, convergence is expected. The question then arises, “What are the drivers and their likely potential to boost economic growth and the catching-up process?”. This paper presents shortly the theoretical background of economic convergence and then focuses on the assessment of possible paths of Romania’s convergence towards the EU. Based on the existing long-term macroeconomic projections and the assessment of the possible future developments of the drivers of economic growth, we have built three scenarios of economic convergence, highlighting the possible timespan of convergence. We have employed growth accounting methods to decompose output growth rate into production factors’ contributions (capital and labour and total factor productivity.

  4. On the Convergence of Iterative Receiver Algorithms Utilizing Hard Decisions

    Directory of Open Access Journals (Sweden)

    Jürgen F. Rößler

    2009-01-01

    Full Text Available The convergence of receivers performing iterative hard decision interference cancellation (IHDIC is analyzed in a general framework for ASK, PSK, and QAM constellations. We first give an overview of IHDIC algorithms known from the literature applied to linear modulation and DS-CDMA-based transmission systems and show the relation to Hopfield neural network theory. It is proven analytically that IHDIC with serial update scheme always converges to a stable state in the estimated values in course of iterations and that IHDIC with parallel update scheme converges to cycles of length 2. Additionally, we visualize the convergence behavior with the aid of convergence charts. Doing so, we give insight into possible errors occurring in IHDIC which turn out to be caused by locked error situations. The derived results can directly be applied to those iterative soft decision interference cancellation (ISDIC receivers whose soft decision functions approach hard decision functions in course of the iterations.

  5. Convergence of Romanian accounting regulations with IFRS. A longitudinal analysis

    Directory of Open Access Journals (Sweden)

    Ioana PĂLĂRIE

    2016-06-01

    Full Text Available In this paper we analyse the evolution in the level of convergence of the Romanian accounting regulations with IFRS in the last decade. We focus our study on the accounting topics covered by IAS16, IAS17, IAS 41 and SIC15. We find that in 2005 the regulations exhibit a good level of convergence for property, plant and equipment, a medium level of convergence for lease accounting and divergence for accounting for the agricultural activity. The overall convergence level improved over time for all the topics analysed. These results indicate that the companies with dual reporting may incur lower costs in applying IFRS. Moreover, the national regulations offer the opportunity for a higher level of comparability in Romania of the financial statements prepared under IFRS with those prepared under national regulations. However, we underline that the institutional factors (such as the tax influence over accounting might negatively affect the convergence of practices.

  6. Convergence of Wachspress coordinates: from polygons to curved domains

    KAUST Repository

    Kosinka, Jiří

    2014-08-08

    Given a smooth, strictly convex planar domain, we investigate point-wise convergence of the sequence of Wachspress coordinates defined over finer and finer inscribed polygonal approximations of the domain. Based on a relation between the discrete Wachspress case and the limit smooth case given by the Wachspress kernel defined by Warren et al., we show that the corresponding sequences of Wachspress interpolants and mappings converge as 𝓞(h2) for a sampling step size h of the boundary curve of the domain as h → 0. Several examples are shown to numerically validate the results and to visualise the behaviour of discrete interpolants and mappings as they converge to their smooth counterparts. Empirically, the same convergence order is observed also for mean value coordinates. Moreover, our numerical tests suggest that the convergence of interpolants and mappings is uniform both in the Wachspress and mean value cases. © 2014 Springer Science+Business Media New York.

  7. Convergence of Wachspress coordinates: from polygons to curved domains

    KAUST Repository

    Kosinka, Jiří ; Barton, Michael

    2014-01-01

    Given a smooth, strictly convex planar domain, we investigate point-wise convergence of the sequence of Wachspress coordinates defined over finer and finer inscribed polygonal approximations of the domain. Based on a relation between the discrete Wachspress case and the limit smooth case given by the Wachspress kernel defined by Warren et al., we show that the corresponding sequences of Wachspress interpolants and mappings converge as 𝓞(h2) for a sampling step size h of the boundary curve of the domain as h → 0. Several examples are shown to numerically validate the results and to visualise the behaviour of discrete interpolants and mappings as they converge to their smooth counterparts. Empirically, the same convergence order is observed also for mean value coordinates. Moreover, our numerical tests suggest that the convergence of interpolants and mappings is uniform both in the Wachspress and mean value cases. © 2014 Springer Science+Business Media New York.

  8. Design of permanent block stopping to resist strata convergence

    Energy Technology Data Exchange (ETDEWEB)

    Ray, R.E.

    1985-11-01

    Conventional concrete block plastered with a cementitious coating is the most common material used in the construction of permanent stoppings to direct airflow in underground mines in the US. All mines experience various degrees of strata convergence depending on depth of overburden, geological conditions, and type of roof support employed. Strata convergence will cause cracks and joint openings in masonry stoppings, resulting in significant air leakage losses. Where strata convergence is severe, complete structural failure of the stopping can ultimately occur. Reconstruction of damaged or destroyed stoppings adds expensive overheads to mining operations, and even greater expenses are incurred from the additional fan horsepower required to overcome leakage losses. Ideally, a stopping should maintain high resistance to airflow while yielding to strata convergence. By properly incorporating a polyisocyanurate rigid foam material within the masonry block structure, stopping service life can be increased in mines experiencing strata convergence problems such as floor heave, roof loading, and lateral rib movement.

  9. Segment-Specific Adhesion as a Driver of Convergent Extension

    Science.gov (United States)

    Vroomans, Renske M. A.; Hogeweg, Paulien; ten Tusscher, Kirsten H. W. J.

    2015-01-01

    Convergent extension, the simultaneous extension and narrowing of tissues, is a crucial event in the formation of the main body axis during embryonic development. It involves processes on multiple scales: the sub-cellular, cellular and tissue level, which interact via explicit or intrinsic feedback mechanisms. Computational modelling studies play an important role in unravelling the multiscale feedbacks underlying convergent extension. Convergent extension usually operates in tissue which has been patterned or is currently being patterned into distinct domains of gene expression. How such tissue patterns are maintained during the large scale tissue movements of convergent extension has thus far not been investigated. Intriguingly, experimental data indicate that in certain cases these tissue patterns may drive convergent extension rather than requiring safeguarding against convergent extension. Here we use a 2D Cellular Potts Model (CPM) of a tissue prepatterned into segments, to show that convergent extension tends to disrupt this pre-existing segmental pattern. However, when cells preferentially adhere to cells of the same segment type, segment integrity is maintained without any reduction in tissue extension. Strikingly, we demonstrate that this segment-specific adhesion is by itself sufficient to drive convergent extension. Convergent extension is enhanced when we endow our in silico cells with persistence of motion, which in vivo would naturally follow from cytoskeletal dynamics. Finally, we extend our model to confirm the generality of our results. We demonstrate a similar effect of differential adhesion on convergent extension in tissues that can only extend in a single direction (as often occurs due to the inertia of the head region of the embryo), and in tissues prepatterned into a sequence of domains resulting in two opposing adhesive gradients, rather than alternating segments. PMID:25706823

  10. BRICS: Evolution and Convergence of Powers

    Directory of Open Access Journals (Sweden)

    Vatanyar Saidovich Yagya

    2016-12-01

    Full Text Available Conducting of foreign policy solely by means of classical diplomacy today seems inefficient. States are supposed to use additional set of tools that have traditionally been at the confluence of soft and hard powers. Convergence of these concepts launched the emergence of such strategies, as smart power and hybrid power that we analyze as a system in relation to such a phenomenon, as BRICS. In the first part of paper we contemplate the concept of power and further expand it to the theoretical ground of each of these strategies along with the existing experience and prospects of their implementation in the BRICS countries. Systematic analysis is taken as the basis of the methodology of this paper, which allowed us to explore this theme separately for each of the BRICS countries and collectively as a system. Feasibility of a number of our provisions is confirmed by relevant case studies and analyses of the most relevant Russian and foreign literature, which results in our main conclusions. Current trends indicate that the BRICS countries are actively expanding its presence in all the key sectors of the global economy and politics. BRICS is at an early stage of implementation of own formats and tools of smart and hybrid powers, the role of which will steadily increase in the international activities of the group, adding value to its arsenal of traditional diplomacy. The potential capacity of soft, smart and hybrid powers of BRICS aims at helping countries to achieve a new level of integration and attractiveness in the eyes of the international community, and will also allow countries to strengthen their positions.

  11. Framework of cloud parameterization including ice for 3-D mesoscale models

    Energy Technology Data Exchange (ETDEWEB)

    Levkov, L; Jacob, D; Eppel, D; Grassl, H

    1989-01-01

    A parameterization scheme for the simulation of ice in clouds incorporated into the hydrostatic version of the GKSS three-dimensional mesoscale model. Numerical simulations of precipitation are performed: over the Northe Sea, the Hawaiian trade wind area and in the region of the intertropical convergence zone. Not only some major features of convective structures in all three areas but also cloud-aerosol interactions have successfully been simulated. (orig.) With 19 figs., 2 tabs.

  12. The tropical Atlantic surface wind divergence belt and its effect on clouds

    OpenAIRE

    Y. Tubul; I. Koren; O. Altaratz

    2015-01-01

    A well-defined surface wind divergence (SWD) belt with distinct cloud properties forms over the equatorial Atlantic during the boreal summer months. This belt separates the deep convective clouds of the intertropical convergence zone (ITCZ) from the shallow marine stratocumulus cloud decks forming over the cold-water subtropical region of the southern Hadley cell. Using the QuikSCAT-SeaWinds and Aqua-MODIS instruments, we examined the large-scale spatiotemporal ...

  13. The tropical Atlantic surface wind divergence belt and its effect on clouds

    OpenAIRE

    Y. Tubul; I. Koren; O. Altaratz

    2015-01-01

    A well-defined surface wind divergence (SWD) belt with distinct cloud properties forms over the equatorial Atlantic during the boreal summer months. This belt separates the deep convective clouds of the Intertropical Convergence Zone (ITCZ) from the shallow marine stratocumulus cloud decks forming over the cold-water subtropical region of the southern branch of the Hadley cell in the Atlantic. Using the QuikSCAT-SeaWinds and Aqua-MODIS instruments, we examined the large-scal...

  14. Distribution and provenance of wind-blown SE Pacific surface sediments

    OpenAIRE

    Saukel, C.; Lamy, F.; Stuut, J.B.W.; Tiedemann, R.; Vogt, C.

    2011-01-01

    The reconstruction of low-latitude ocean-atmosphere interactions is one of the major issues of (paleo-) environmental studies. The trade winds, extending over 20 degrees to 30 degrees of latitude in both hemispheres, between the subtropical highs and the intertropical convergence zone, are major components of the atmospheric circulation and little is known about their long-term variability on geological time-scales, in particular in the Pacific sector. We present the modern spatial pattern of...

  15. Christmas Island lagoonal lakes, models for the deposition of carbonate–evaporite–organic laminated sediments

    OpenAIRE

    Trichet , Jean; Défarge , Christian; Tribble , J.; Tribble , G.W.; Sansone , F.J.

    2001-01-01

    The atoll of Christmas Island (now known as Kiritimati) in the Kiribati Republic (Central Pacific) lies at about 2°N in the intertropical convergence zone. Much of the surface area of the atoll (ca. 360 km2) is occupied by numerous lakes in which carbonate, evaporite (calcium sulfate, halite) and organic layers are deposited. Observations suggest that deposition of these different laminae is controlled by climatic and biologic factors. It is thought that periodic climatic variations, such as ...

  16. Reliability enhancement of Navier-Stokes codes through convergence acceleration

    Science.gov (United States)

    Merkle, Charles L.; Dulikravich, George S.

    1995-01-01

    Methods for enhancing the reliability of Navier-Stokes computer codes through improving convergence characteristics are presented. The improving of these characteristics decreases the likelihood of code unreliability and user interventions in a design environment. The problem referred to as a 'stiffness' in the governing equations for propulsion-related flowfields is investigated, particularly in regard to common sources of equation stiffness that lead to convergence degradation of CFD algorithms. Von Neumann stability theory is employed as a tool to study the convergence difficulties involved. Based on the stability results, improved algorithms are devised to ensure efficient convergence in different situations. A number of test cases are considered to confirm a correlation between stability theory and numerical convergence. The examples of turbulent and reacting flow are presented, and a generalized form of the preconditioning matrix is derived to handle these problems, i.e., the problems involving additional differential equations for describing the transport of turbulent kinetic energy, dissipation rate and chemical species. Algorithms for unsteady computations are considered. The extension of the preconditioning techniques and algorithms derived for Navier-Stokes computations to three-dimensional flow problems is discussed. New methods to accelerate the convergence of iterative schemes for the numerical integration of systems of partial differential equtions are developed, with a special emphasis on the acceleration of convergence on highly clustered grids.

  17. Optimizer convergence and local minima errors and their clinical importance

    International Nuclear Information System (INIS)

    Jeraj, Robert; Wu, Chuan; Mackie, Thomas R

    2003-01-01

    Two of the errors common in the inverse treatment planning optimization have been investigated. The first error is the optimizer convergence error, which appears because of non-perfect convergence to the global or local solution, usually caused by a non-zero stopping criterion. The second error is the local minima error, which occurs when the objective function is not convex and/or the feasible solution space is not convex. The magnitude of the errors, their relative importance in comparison to other errors as well as their clinical significance in terms of tumour control probability (TCP) and normal tissue complication probability (NTCP) were investigated. Two inherently different optimizers, a stochastic simulated annealing and deterministic gradient method were compared on a clinical example. It was found that for typical optimization the optimizer convergence errors are rather small, especially compared to other convergence errors, e.g., convergence errors due to inaccuracy of the current dose calculation algorithms. This indicates that stopping criteria could often be relaxed leading into optimization speed-ups. The local minima errors were also found to be relatively small and typically in the range of the dose calculation convergence errors. Even for the cases where significantly higher objective function scores were obtained the local minima errors were not significantly higher. Clinical evaluation of the optimizer convergence error showed good correlation between the convergence of the clinical TCP or NTCP measures and convergence of the physical dose distribution. On the other hand, the local minima errors resulted in significantly different TCP or NTCP values (up to a factor of 2) indicating clinical importance of the local minima produced by physical optimization

  18. Convergence of spectral methods for nonlinear conservation laws. Final report

    International Nuclear Information System (INIS)

    Tadmor, E.

    1987-08-01

    The convergence of the Fourier method for scalar nonlinear conservation laws which exhibit spontaneous shock discontinuities is discussed. Numerical tests indicate that the convergence may (and in fact in some cases must) fail, with or without post-processing of the numerical solution. Instead, a new kind of spectrally accurate vanishing viscosity is introduced to augment the Fourier approximation of such nonlinear conservation laws. Using compensated compactness arguments, it is shown that this spectral viscosity prevents oscillations, and convergence to the unique entropy solution follows

  19. Towards automated composition of convergent services: A survey

    OpenAIRE

    Ordónez, Armando; Alcazar, Vidal; Rendon, Oscar Mauricio Caicedo; Falcarin, Paolo; Corrales, Juan C.; Granville, Lisandro Zambenedetti

    2015-01-01

    A convergent service is defined as a service that exploits the convergence of\\ud communication networks and at the same time takes advantage of features of\\ud the Web. Nowadays, building up a convergent service is not trivial, because\\ud although there are significant approaches that aim to automate the service\\ud composition at different levels in the Web and Telecom domains, selecting\\ud the most appropriate approach for specific case studies is complex due to\\ud the big amount of involved ...

  20. Convergence of third order correlation energy in atoms and molecules.

    Science.gov (United States)

    Kahn, Kalju; Granovsky, Alex A; Noga, Jozef

    2007-01-30

    We have investigated the convergence of third order correlation energy within the hierarchies of correlation consistent basis sets for helium, neon, and water, and for three stationary points of hydrogen peroxide. This analysis confirms that singlet pair energies converge much slower than triplet pair energies. In addition, singlet pair energies with (aug)-cc-pVDZ and (aug)-cc-pVTZ basis sets do not follow a converging trend and energies with three basis sets larger than aug-cc-pVTZ are generally required for reliable extrapolations of third order correlation energies, making so the explicitly correlated R12 calculations preferable.

  1. Variable convergence liquid layer implosions on the National Ignition Facility

    Science.gov (United States)

    Zylstra, A. B.; Yi, S. A.; Haines, B. M.; Olson, R. E.; Leeper, R. J.; Braun, T.; Biener, J.; Kline, J. L.; Batha, S. H.; Berzak Hopkins, L.; Bhandarkar, S.; Bradley, P. A.; Crippen, J.; Farrell, M.; Fittinghoff, D.; Herrmann, H. W.; Huang, H.; Khan, S.; Kong, C.; Kozioziemski, B. J.; Kyrala, G. A.; Ma, T.; Meezan, N. B.; Merrill, F.; Nikroo, A.; Peterson, R. R.; Rice, N.; Sater, J. D.; Shah, R. C.; Stadermann, M.; Volegov, P.; Walters, C.; Wilson, D. C.

    2018-05-01

    Liquid layer implosions using the "wetted foam" technique, where the liquid fuel is wicked into a supporting foam, have been recently conducted on the National Ignition Facility for the first time [Olson et al., Phys. Rev. Lett. 117, 245001 (2016)]. We report on a series of wetted foam implosions where the convergence ratio was varied between 12 and 20. Reduced nuclear performance is observed as convergence ratio increases. 2-D radiation-hydrodynamics simulations accurately capture the performance at convergence ratios (CR) ˜ 12, but we observe a significant discrepancy at CR ˜ 20. This may be due to suppressed hot-spot formation or an anomalous energy loss mechanism.

  2. Semi-convergence properties of Kaczmarz’s method

    DEFF Research Database (Denmark)

    Elfving, Tommy; Hansen, Per Christian; Nikazad, Touraj

    2014-01-01

    Kaczmarz’s method—sometimes referred to as the algebraic reconstruction technique—is an iterative method that is widely used in tomographic imaging due to its favorable semi-convergence properties. Specifically, when applied to a problem with noisy data, during the early iterations it converges......-convergence of Kaczmarz’s method as well as its projected counterpart (and their block versions). To do this we study how the data errors propagate into the iteration vectors and we derive upper bounds for this noise propagation. Our bounds are compared with numerical results obtained from tomographic imaging....

  3. Geophysical constraints on geodynamical processes at convergent margins

    DEFF Research Database (Denmark)

    Artemieva, Irina; Thybo, Hans; Shulgin, Alexey

    2016-01-01

    Convergent margins, being the boundaries between colliding lithospheric plates, form the most disastrous areas in the world due to intensive, strong seismicity and volcanism. We review global geophysical data in order to illustrate the effects of the plate tectonic processes at convergent margins......, at least, one of the plates is oceanic. However, the oldest oceanic plate in the Pacific ocean has the smallest convergence rate. (2) The presence of an oceanic plate is, in general, required for generation of high-magnitude (M>8.0) earthquakes and for generating intermediate and deep seismicity along...... to shallow mantle levels....

  4. On projection methods, convergence and robust formulations in topology optimization

    DEFF Research Database (Denmark)

    Wang, Fengwen; Lazarov, Boyan Stefanov; Sigmund, Ole

    2011-01-01

    alleviated using various projection methods. In this paper we show that simple projection methods do not ensure local mesh-convergence and propose a modified robust topology optimization formulation based on erosion, intermediate and dilation projections that ensures both global and local mesh-convergence.......Mesh convergence and manufacturability of topology optimized designs have previously mainly been assured using density or sensitivity based filtering techniques. The drawback of these techniques has been gray transition regions between solid and void parts, but this problem has recently been...

  5. Convergent close-coupling calculations of electron-hydrogen scattering

    International Nuclear Information System (INIS)

    Bray, Igor; Stelbovics, A.T.

    1992-04-01

    The convergence of the close-coupling formalism is studied by expanding the target states in an orthogonal L 2 Laguerre basis. The theory is without approximation and convergence is established by simply increasing the basis size. The convergent elastic, 2s, and 2p differential cross sections, spin asymmetries, and angular correlation parameters for the 2p excitation at 35, 54.4, and 100 eV are calculated. Integrated and total cross sections as well as T-matrix elements for the first five partial waves are also given. 30 refs., 3 tabs., 9 figs

  6. Convergence of the multiple scattering expansion in XAFS and XANES

    International Nuclear Information System (INIS)

    Rehr, J.J.

    1992-01-01

    The convergence of the multiple-scattering expansion of XAFS and XANES by explicit path-bypath calculations. The approach is based on the fast scattering matrix formalism of Rehr and Albers, together with an automated path finder and filters that exclude negligible paths. High-order scattering terms are found to be essential, especially at low energies. Several factors including the magnitude of curved wave scattering amplitudes, inelastic losses and multiple-scattering Debye-Waller factors control convergence of the expansion. The convergence is illustrated explicitly for the case of diatomic molecules

  7. Convergence analysis for column-action methods in image reconstruction

    DEFF Research Database (Denmark)

    Elfving, Tommy; Hansen, Per Christian; Nikazad, Touraj

    2016-01-01

    Column-oriented versions of algebraic iterative methods are interesting alternatives to their row-version counterparts: they converge to a least squares solution, and they provide a basis for saving computational work by skipping small updates. In this paper we consider the case of noise-free data....... We present a convergence analysis of the column algorithms, we discuss two techniques (loping and flagging) for reducing the work, and we establish some convergence results for methods that utilize these techniques. The performance of the algorithms is illustrated with numerical examples from...

  8. Zones of emotional labour

    DEFF Research Database (Denmark)

    Strøbæk, Pernille Solveig

    2011-01-01

    The paper suggests that due to the difficult nature of their work public family law caseworkers are to be included in the definition of emotional labour even though they are omitted by Hochschild. Based upon a review of the structures involved in emotional labour an explorative qualitative study...... is put forth among 25 Danish public family law caseworkers. The study points to personal, professional, and social zones of emotional labour through which the caseworkers carry out their work. Emotional labour zones mark emotion structures that may be challenging due to complex emotional intersections...

  9. Nuclear free zone

    International Nuclear Information System (INIS)

    Christoffel, T.

    1987-01-01

    Health professionals have played a leading role in alerting and educating the public regarding the danger of nuclear war which has been described as the last epidemic our civilization will know. Having convinced most people that the use of nuclear weapons would mean intolerable consequences, groups such as Physicians for Social Responsibility have focused on the second critical question how likely is it that these weapons will be used? The oultlook is grim. This article describes the nuclear free zone movement, explores relevant legal questions, and shows how the political potential of nuclear free zones threatens to open a deep rift in the American constitutional system

  10. Optimal exploration target zones

    CSIR Research Space (South Africa)

    Debba, Pravesh

    2008-09-01

    Full Text Available -of-evidence (WofE) method logistic regression canonical favorability analysis neural networks evidential belief functions Optimal Exploration Target Zones Debba, Carranza, Stein, van der Meer Introduction to Remote Sensing Background and Objective of the study... for the following equation: n∑ i=r ( n i ) pi(1− p)n−i = 0.95 . (1) Optimal Exploration Target Zones Debba, Carranza, Stein, van der Meer Introduction to Remote Sensing Background and Objective of the study Methodology Results METHODS (cont. . . ): FITNESS FUNCTION...

  11. Dike zones on Venus

    Science.gov (United States)

    Markov, M. S.; Sukhanov, A. L.

    1987-01-01

    Venusian dike zone structures were identified from Venera 15 and 16 radar images. These include: a zone of subparallel rows centered at 30 deg N, 7 deg E; a system of intersecting bands centered at 67 deg N, 284 deg E; polygonal systems in lavas covering the structural base uplift centered at 47 deg N, 200 deg E; a system of light bands in the region of the ring structure centered at 43 deg N, 13 deg E; and a dike band centered at 27 deg N, 36 deg E.

  12. On convergence and convergence rates for Ivanov and Morozov regularization and application to some parameter identification problems in elliptic PDEs

    Science.gov (United States)

    Kaltenbacher, Barbara; Klassen, Andrej

    2018-05-01

    In this paper we provide a convergence analysis of some variational methods alternative to the classical Tikhonov regularization, namely Ivanov regularization (also called the method of quasi solutions) with some versions of the discrepancy principle for choosing the regularization parameter, and Morozov regularization (also called the method of the residuals). After motivating nonequivalence with Tikhonov regularization by means of an example, we prove well-definedness of the Ivanov and the Morozov method, convergence in the sense of regularization, as well as convergence rates under variational source conditions. Finally, we apply these results to some linear and nonlinear parameter identification problems in elliptic boundary value problems.

  13. Almost everywhere convergence over cubes of multiple trigonometric Fourier series

    International Nuclear Information System (INIS)

    Antonov, N Yu

    2004-01-01

    Under certain conditions on a function φ:[0,+∞)→[0,+∞) we prove a theorem asserting that the convergence almost everywhere of trigonometric Fourier series for all functions of class φ(L) [-π,π) implies the convergence over cubes of the multiple Fourier series and all its conjugates for an arbitrary function f element of φ(L)(log + L) d-1 ) [-π,π) d , d element of N. It follows from this and an earlier result of the author on the convergence almost everywhere of Fourier series of functions of one variable and class L(log + L)(log + log + log + L)) [-π,π) that if f element of L(log + L) d (log + log + log + L)) [-π,π) d , d element of N, then the Fourier series of f and all its conjugates converge over cubes almost everywhere

  14. System convergence in transport models: algorithms efficiency and output uncertainty

    DEFF Research Database (Denmark)

    Rich, Jeppe; Nielsen, Otto Anker

    2015-01-01

    of this paper is to analyse convergence performance for the external loop and to illustrate how an improper linkage between the converging parts can lead to substantial uncertainty in the final output. Although this loop is crucial for the performance of large-scale transport models it has not been analysed...... much in the literature. The paper first investigates several variants of the Method of Successive Averages (MSA) by simulation experiments on a toy-network. It is found that the simulation experiments produce support for a weighted MSA approach. The weighted MSA approach is then analysed on large......-scale in the Danish National Transport Model (DNTM). It is revealed that system convergence requires that either demand or supply is without random noise but not both. In that case, if MSA is applied to the model output with random noise, it will converge effectively as the random effects are gradually dampened...

  15. Heterogeneous Network Convergence with Artificial Mapping for Cognitive Radio Networks

    Directory of Open Access Journals (Sweden)

    Hang QIN

    2013-04-01

    Full Text Available The artificial mapping scheme is proposed in this paper for adaptive network collaboration of cognitive radio networks. The superiority of the DHT-based overlay for its link state aggregation property, which establishes global convergence for link state aggregation message among a scalable number of nodes, is considered in the analysis. In addition, the fuzzy logic inference can better handle uncertainty, fuzziness, and incomplete information in node convergence report, which is developed as a novel approach to aggregate wireless node control with affordable message overload. The Artificial Mapping Tree (AMT for the new convergence scheme is verified by the simulation and experimental results. The moderately increased network throughput for convergence validation is demonstrated with the proactive spectrum coordination.

  16. Effects of radiation-counselling convergence education on radiation awareness

    Energy Technology Data Exchange (ETDEWEB)

    Seoung, Youl Hun [Dept. of Radiological Science, College of Health Science, Cheongju University, Cheongju (Korea, Republic of)

    2017-06-15

    The purpose of study was to analysis on the effects of radiation-counselling convergence education on radiation awareness. The survey objects were students of radiation-counselling convergence education from 12th May to 22th June in 2016. The questionnaires were education satisfactions and radiation awareness (risk, benefit, control) by Likert-type 5 scales. The analysis results revealed that education satisfactions of men students showed a significant higher female students and correlation coefficient of education satisfactions were the best high in the benefit and control of radiation. Finally radiation-counselling convergence education had a significant effect on radiation benefit. This convergence education influenced positive recognition on radiation benefit and it was indicated that radiation-counselors could treat clients on the basis of radiation benefit.

  17. Field convergence between technical writers and technical translators

    DEFF Research Database (Denmark)

    Gnecchi, M.; Maylath, B.; Mousten, Birthe

    2011-01-01

    As translation of technical documents continues to grow rapidly and translation becomes more automated, the roles of professional communicators and translators appear to be converging. This paper updates preliminary findings first presented at the 2008 International Professional Communication...

  18. Convergence diagnostics for Eigenvalue problems with linear regression model

    International Nuclear Information System (INIS)

    Shi, Bo; Petrovic, Bojan

    2011-01-01

    Although the Monte Carlo method has been extensively used for criticality/Eigenvalue problems, a reliable, robust, and efficient convergence diagnostics method is still desired. Most methods are based on integral parameters (multiplication factor, entropy) and either condense the local distribution information into a single value (e.g., entropy) or even disregard it. We propose to employ the detailed cycle-by-cycle local flux evolution obtained by using mesh tally mechanism to assess the source and flux convergence. By applying a linear regression model to each individual mesh in a mesh tally for convergence diagnostics, a global convergence criterion can be obtained. We exemplify this method on two problems and obtain promising diagnostics results. (author)

  19. Safety performance evaluation of converging chevron pavement markings : final report.

    Science.gov (United States)

    2014-12-01

    The objectives of this study were (1) to perform a detailed safety analysis of converging chevron : pavement markings, quantifying the potential safety benefits and developing an understanding of the : incident types addressed by the treatment, and (...

  20. Convergent Difference Schemes for Hamilton-Jacobi equations

    KAUST Repository

    Duisembay, Serikbolsyn

    2018-01-01

    In this thesis, we consider second-order fully nonlinear partial differential equations of elliptic type. Our aim is to develop computational methods using convergent difference schemes for stationary Hamilton-Jacobi equations with Dirichlet

  1. L1-convergence of complex double Fourier series

    Indian Academy of Sciences (India)

    -Convergence of ... School of Mathematics and Computer Applications, Thapar Institute of Engineering and Technology, Post Box No. 32, Patiala 147 004, India; Department of Mathematics, Maharshi Dayanand University, Rohtak, India ...

  2. Albania and the EU: A path to convergence?

    Directory of Open Access Journals (Sweden)

    Javier Lopez-Prol

    2014-11-01

    Full Text Available The aim of this paper is to assess the degree of relative convergence achieved by Albania in relation to the EU during the last decade through a descriptive empirical analysis. The paper is divided into three sections related to real and nominal convergence in the fields of economic performance; trade openness and balance; and monetary convergence, according to the Euro criteria established in the art. 140 (1 of the TFEU and the protocol Nº 13 (price stability, public finances, exchange rate, and long-term interest rates. In order to have a wide perspective about convergence-divergence trends inside and outside the EU, the tendencies followed by Germany and Greece are also mentioned, as paradigmatic cases of divergence within the EU. Finally, a summary table is presented reviewing each of the analysed variables regarding the last decade evolution and the current situation.

  3. Convergent engineering techniques for management of nuclear processes

    International Nuclear Information System (INIS)

    Carabulea, A.; Popa, I.

    1995-01-01

    The paper briefly presents the concept of convergent arhemo-systematical engineering, its advantages in comparison with classical methods of research, design, manufacture. The convergent engineering application supposes the usage of the advanced methods, techniques and equipment corresponding to the domain and specific for the corresponding branch of computer science. Starting from the convergent engineering principles and concept, the paper proposes two models applicable for new products and also for improving and optimizing the existing ones. The models are based on two levels of feedback corresponding to two levels of control and they assume the utilization of expert and robot-expert systems. The economical efficiency of the application of the convergent engineering method is evaluated for the case of a nuclear power plant by calculation the main technical and economical indicators. (Author) 2 Figs., 5 Refs

  4. Effects of radiation-counselling convergence education on radiation awareness

    International Nuclear Information System (INIS)

    Seoung, Youl Hun

    2017-01-01

    The purpose of study was to analysis on the effects of radiation-counselling convergence education on radiation awareness. The survey objects were students of radiation-counselling convergence education from 12th May to 22th June in 2016. The questionnaires were education satisfactions and radiation awareness (risk, benefit, control) by Likert-type 5 scales. The analysis results revealed that education satisfactions of men students showed a significant higher female students and correlation coefficient of education satisfactions were the best high in the benefit and control of radiation. Finally radiation-counselling convergence education had a significant effect on radiation benefit. This convergence education influenced positive recognition on radiation benefit and it was indicated that radiation-counselors could treat clients on the basis of radiation benefit

  5. Convergence Analysis of a Class of Computational Intelligence Approaches

    Directory of Open Access Journals (Sweden)

    Junfeng Chen

    2013-01-01

    Full Text Available Computational intelligence approaches is a relatively new interdisciplinary field of research with many promising application areas. Although the computational intelligence approaches have gained huge popularity, it is difficult to analyze the convergence. In this paper, a computational model is built up for a class of computational intelligence approaches represented by the canonical forms of generic algorithms, ant colony optimization, and particle swarm optimization in order to describe the common features of these algorithms. And then, two quantification indices, that is, the variation rate and the progress rate, are defined, respectively, to indicate the variety and the optimality of the solution sets generated in the search process of the model. Moreover, we give four types of probabilistic convergence for the solution set updating sequences, and their relations are discussed. Finally, the sufficient conditions are derived for the almost sure weak convergence and the almost sure strong convergence of the model by introducing the martingale theory into the Markov chain analysis.

  6. Multi-sectorial convergence in greenhouse gas emissions.

    Science.gov (United States)

    Oliveira, Guilherme de; Bourscheidt, Deise Maria

    2017-07-01

    This paper uses the World Input-Output Database (WIOD) to test the hypothesis of per capita convergence in greenhouse gas (GHG) emissions for a multi-sectorial panel of countries. The empirical strategy applies conventional estimators of random and fixed effects and Arellano and Bond's (1991) GMM to the main pollutants related to the greenhouse effect. For reasonable empirical specifications, the model revealed robust evidence of per capita convergence in CH 4 emissions in the agriculture, food, and services sectors. The evidence of convergence in CO 2 emissions was moderate in the following sectors: agriculture, food, non-durable goods manufacturing, and services. In all cases, the time for convergence was less than 15 years. Regarding emissions by energy use, the largest source of global warming, there was only moderate evidence in the extractive industry sector-all other pollutants presented little or no evidence. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Romania's Agriculture and its Role in the Convergence Process

    Directory of Open Access Journals (Sweden)

    CONSTANTIN POSTOIU

    2015-05-01

    Full Text Available The importance of agriculture in Romania is linked to the fact that 45% of its population is in the rural area, mostly dependent on agricultural activities. This paper aims to determine in what extent agriculture influences the convergence process of Romania with the euro area. The structural convergence index is computed in order to assess the degree in which the structure of the Romanian economy resembles the one of the euro area in terms of both gross value added and employment. Research indicates that Romania has the lowest score in terms of structural convergence with the euro area. The main reason is the oversized agricultural sector which employs almost a third of the active population. The productivity of the Romanian agriculture is then assessed in order to identify its possible effect on the country’s overall competitiveness and on the whole convergence process.

  8. Learning by Investing, Embodiment, and Speed of Convergence

    DEFF Research Database (Denmark)

    Groth, Christian; Wendner, Ronald

    This paper sets up a dynamic general equilibrium model to study how the composition of technical progress affects the asymptotic speed of convergence. The following questions are addressed: Will endogenizing a fraction of the productivity increases as coming from learning by investing help...... to generate a low asymptotic speed of convergence in accordance with the empirical evidence? Does it matter whether learning originates in gross or net investment? The answers to both questions turn out to be: yes, a lot. The third question addressed is: Does the speed of convergence significantly depend...... on the degree to which learning by investing takes the embodied form rather than the disembodied form? The answer turns out to be: no. These results point to a speed of convergence on the small side of 2% per year and possibly tending to a lower level in the future due to the rising importance of investment...

  9. Challenges and opportunities of convergence in building a knowledge economy

    CSIR Research Space (South Africa)

    Jolliffe, B

    2006-08-01

    Full Text Available Slides include: What is the knowledge economy? Drivers; Will it contribute to development? Development as freedom; Knowledge Economy, ICTs, convergence etc; Ducks to put in a row; Patents and knowledge economy; South Africa? Threat to local...

  10. A convergent overlapping domain decomposition method for total variation minimization

    KAUST Repository

    Fornasier, Massimo; Langer, Andreas; Schö nlieb, Carola-Bibiane

    2010-01-01

    In this paper we are concerned with the analysis of convergent sequential and parallel overlapping domain decomposition methods for the minimization of functionals formed by a discrepancy term with respect to the data and a total variation

  11. Did capital market convergence lower the effectiveness of monetary policy?

    NARCIS (Netherlands)

    Jansen, P.W.

    2009-01-01

    International capital market convergence reduces the ability for monetary authorities to set domestic monetary conditions. Traditionally, monetary policy transmission is channelled through the short-term interest rate. Savings and investment decisions are effected through the response of the bond

  12. Cosmological constraints from the convergence 1-point probability distribution

    Energy Technology Data Exchange (ETDEWEB)

    Patton, Kenneth [The Ohio State Univ., Columbus, OH (United States); Blazek, Jonathan [The Ohio State Univ., Columbus, OH (United States); Ecole Polytechnique Federale de Lausanne (EPFL), Versoix (Switzerland); Honscheid, Klaus [The Ohio State Univ., Columbus, OH (United States); Huff, Eric [The Ohio State Univ., Columbus, OH (United States); California Inst. of Technology (CalTech), Pasadena, CA (United States); Melchior, Peter [Princeton Univ., Princeton, NJ (United States); Ross, Ashley J. [The Ohio State Univ., Columbus, OH (United States); Suchyta, Eric D. [The Ohio State Univ., Columbus, OH (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-06-29

    Here, we examine the cosmological information available from the 1-point probability density function (PDF) of the weak-lensing convergence field, utilizing fast l-picola simulations and a Fisher analysis. We find competitive constraints in the Ωm–σ8 plane from the convergence PDF with 188 arcmin2 pixels compared to the cosmic shear power spectrum with an equivalent number of modes (ℓ < 886). The convergence PDF also partially breaks the degeneracy cosmic shear exhibits in that parameter space. A joint analysis of the convergence PDF and shear 2-point function also reduces the impact of shape measurement systematics, to which the PDF is less susceptible, and improves the total figure of merit by a factor of 2–3, depending on the level of systematics. Finally, we present a correction factor necessary for calculating the unbiased Fisher information from finite differences using a limited number of cosmological simulations.

  13. Heterotic quantum and classical computing on convergence spaces

    Science.gov (United States)

    Patten, D. R.; Jakel, D. W.; Irwin, R. J.; Blair, H. A.

    2015-05-01

    Category-theoretic characterizations of heterotic models of computation, introduced by Stepney et al., combine computational models such as classical/quantum, digital/analog, synchronous/asynchronous, etc. to obtain increased computational power. A highly informative classical/quantum heterotic model of computation is represented by Abramsky's simple sequential imperative quantum programming language which extends the classical simple imperative programming language to encompass quantum computation. The mathematical (denotational) semantics of this classical language serves as a basic foundation upon which formal verification methods can be developed. We present a more comprehensive heterotic classical/quantum model of computation based on heterotic dynamical systems on convergence spaces. Convergence spaces subsume topological spaces but admit finer structure from which, in prior work, we obtained differential calculi in the cartesian closed category of convergence spaces allowing us to define heterotic dynamical systems, given by coupled systems of first order differential equations whose variables are functions from the reals to convergence spaces.

  14. Arithmetic convergent sequence space defined by modulus function

    Directory of Open Access Journals (Sweden)

    Taja Yaying

    2019-10-01

    Full Text Available The aim of this article is to introduce the sequence spaces $AC(f$ and $AS(f$ using arithmetic convergence and modulus function, and study algebraic and topological properties of this space, and certain inclusion results.

  15. Convergent landscape. 39 and a half as (multi promotional intertext

    Directory of Open Access Journals (Sweden)

    Katarzyna Kopecka- Piech

    2010-12-01

    Full Text Available The purpose of this article is to provide a broader characterisation of the media convergence strategy applied by producers of the Polish commercial television station (TVN series 39 and a half (39 i pół. In order to examine the convergence strategies of production, distribution, promotion and media usage, this paper analyzes metaphors of landscape, terrain, map and simulacrum. Moreover the concept of convergent (intertext is proposed. In the case study of 39 and a half the author examines three main strategies implemented by the creators: the promotional virtualisation of reality, making virtual reality more real, and multiplied fiction. Transmedial and synergetic brands illustrate the hybridisation of the convergent and integrated media landscape.

  16. Convergence of a residual based artificial viscosity finite element method

    KAUST Repository

    Nazarov, Murtazo

    2013-01-01

    . We prove convergence of the method, applied to a scalar conservation law in two space dimensions, toward an unique entropy solution for implicit time stepping schemes. © 2012 Elsevier B.V. All rights reserved.

  17. Forearc kinematics in obliquely convergent margins: Examples from Nicaragua and the northern Lesser Antilles

    Science.gov (United States)

    Turner, Henry L., III

    In this study, I use surface velocities derived from GPS geodesy, elastic half-space dislocation models, and modeled Coulomb stress changes to investigate deformation in the over-riding plate at obliquely convergent margins at the leading and trailing edges of the Caribbean plate. The two principal study areas are western Nicaragua, where the Cocos plate subducts beneath the Caribbean plate, and the northern Lesser Antilles, where the North American plate subducts beneath the Caribbean plate. In Nicaragua, plate convergence is rapid at 84 mm yr1 with a small angle of obliquity of 10° along a slightly concave portion of the Middle America Trench. GPS velocities for the period from 2000 to 2004 from sites located in the Nicaraguan forearc confirmed forearc sliver motion on the order of ˜14 mm yr1 in close agreement with the value predicted by DeMets (2001). These results are presented here in Chapter 3 and were reported in Geophysical Research Letters (Turner et al., 2007). GPS observations made on sites located in the interior and on the eastern coast of Nicaragua during the same time period were combined with new data from eastern Honduras to help better constrain estimates of rigid Caribbean plate motion (DeMets et al., 2007). Slip approaching the plate convergence rate along the Nicaraguan and El Salvadoran sections of the Middle America Trench was quantitatively demonstrated by finite element modeling of this section of the plate interface using GPS velocities from our Nicaraguan network together with velocities from El Salvador and Honduras as model constraints (Correa-Mora, 2009). The MW 6.9 earthquake that ruptured the seismogenic zone offshore Nicaragua on October 9, 2004 resulted in coseismic displacements and post-seismic motion at GPS sites in the central part of the Nicaraguan forearc that currently prevent extension of interseismic time-series in this region. An elastic half-space dislocation model was used to estimate coseismic displacements at these

  18. Effectiveness of vision therapy in school children with symptomatic convergence insufficiency

    Directory of Open Access Journals (Sweden)

    Jung Un Jang

    2017-01-01

    Conclusion: Among convergence insufficiency symptoms, the following improved in particular: near point of convergence, exophoria, and near positive fusional vergence. These findings suggest that vision therapy is very effective to recover from symptomatic convergence insufficiency.

  19. Convergence of hyperspherical adiabatic expansion for helium-like systems

    International Nuclear Information System (INIS)

    Abrashkevich, A.G.; Abrashkevich, D.G.; Pojda, V.Yu.; Vinitskij, S.I.; Kaschiev, M.S.; Puzynin, I.V.

    1988-01-01

    The convergence of hyperspherical adiabatic expansion has been studied numerically. The spectral problems arising after separation of variables are solved by the finite-difference and finite element methods. The energies of the ground and some doubly excited staes of a hydrogen ion are calculated in the six-channel approximation within the 10 -4 a.u. accuracy. Obtained results demonstrate a rapid convergence of the hyperspherical adiabatic expansion. 14 refs.; 5 tabs

  20. On cylindrically converging shock waves shaped by obstacles

    Energy Technology Data Exchange (ETDEWEB)

    Eliasson, V; Henshaw, W D; Appelo, D

    2007-07-16

    Motivated by recent experiments, numerical simulations were performed of cylindrically converging shock waves. The converging shocks impinged upon a set of zero to sixteen regularly space obstacles. For more than two obstacles the resulting diffracted shock fronts formed polygonal shaped patterns near the point of focus. The maximum pressure and temperature as a function of number of obstacles were studied. The self-similar behavior of cylindrical, triangular and square-shaped shocks were also investigated.

  1. Convergence of Transition Probability Matrix in CLVMarkov Models

    Science.gov (United States)

    Permana, D.; Pasaribu, U. S.; Indratno, S. W.; Suprayogi, S.

    2018-04-01

    A transition probability matrix is an arrangement of transition probability from one states to another in a Markov chain model (MCM). One of interesting study on the MCM is its behavior for a long time in the future. The behavior is derived from one property of transition probabilty matrix for n steps. This term is called the convergence of the n-step transition matrix for n move to infinity. Mathematically, the convergence of the transition probability matrix is finding the limit of the transition matrix which is powered by n where n moves to infinity. The convergence form of the transition probability matrix is very interesting as it will bring the matrix to its stationary form. This form is useful for predicting the probability of transitions between states in the future. The method usually used to find the convergence of transition probability matrix is through the process of limiting the distribution. In this paper, the convergence of the transition probability matrix is searched using a simple concept of linear algebra that is by diagonalizing the matrix.This method has a higher level of complexity because it has to perform the process of diagonalization in its matrix. But this way has the advantage of obtaining a common form of power n of the transition probability matrix. This form is useful to see transition matrix before stationary. For example cases are taken from CLV model using MCM called Model of CLV-Markov. There are several models taken by its transition probability matrix to find its convergence form. The result is that the convergence of the matrix of transition probability through diagonalization has similarity with convergence with commonly used distribution of probability limiting method.

  2. Convergence of Dynamics and the Perron-Frobenius Operator

    OpenAIRE

    Gerlach, Moritz

    2016-01-01

    We complete the picture how the asymptotic behavior of a dynamical system is reflected by properties of the associated Perron-Frobenius operator. Our main result states that strong convergence of the powers of the Perron-Frobenius operator is equivalent to setwise convergence of the underlying dynamic in the measure algebra. This situation is furthermore characterized by a uniform mixing-like property of the system.

  3. Splenic marginal zone lymphoma.

    Science.gov (United States)

    Piris, Miguel A; Onaindía, Arantza; Mollejo, Manuela

    Splenic marginal zone lymphoma (SMZL) is an indolent small B-cell lymphoma involving the spleen and bone marrow characterized by a micronodular tumoral infiltration that replaces the preexisting lymphoid follicles and shows marginal zone differentiation as a distinctive finding. SMZL cases are characterized by prominent splenomegaly and bone marrow and peripheral blood infiltration. Cells in peripheral blood show a villous cytology. Bone marrow and peripheral blood characteristic features usually allow a diagnosis of SMZL to be performed. Mutational spectrum of SMZL identifies specific findings, such as 7q loss and NOTCH2 and KLF2 mutations, both genes related with marginal zone differentiation. There is a striking clinical variability in SMZL cases, dependent of the tumoral load and performance status. Specific molecular markers such as 7q loss, p53 loss/mutation, NOTCH2 and KLF2 mutations have been found to be associated with the clinical variability. Distinction from Monoclonal B-cell lymphocytosis with marginal zone phenotype is still an open issue that requires identification of precise and specific thresholds with clinical meaning. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Nuclear weapons free zones

    International Nuclear Information System (INIS)

    Stahl, K.

    1990-01-01

    The article analyses the concept and problems of the two nuclear weapons free zones in Latin America and in the South Pacific established by the Treaty of Tlatelolco and the Treaty of Rarotonga. So far the nuclear weapons states except China have refused to sign the additional protocols of the Treaties or have signed them only with considerable provisos. Therefore they don't fully recognize the nuclear weapons free status of those zones, or they don't recognize it at all. Both Treaties contain no provisions to regulate the transit of nuclear weapons through the zones. This allows de facto the stationing of nuclear weapons in the military bases of the US which are located within the nuclear weapons free zone of Latin America. The Treaty of Tlatelolco contains also the right of the states, party to the Treaty, to explode nuclear devices for peaceful purposes. Since peaceful and military nuclear explosions cannot be distinguished technically, this right could also undermine the nuclear weapons free status of the region. Important nuclear threshold countries like Argentina and Brazil have furthermore refrained from putting the Treaty into force. (orig.) [de

  5. Navigating ECA-Zones

    DEFF Research Database (Denmark)

    Hansen, Carsten Ørts; Grønsedt, Peter; Hendriksen, Christian

    This report examines the effect that ECA-zone regulation has on the optimal vessel fuel strategies for compliance. The findings of this report are trifold, and this report is coupled with a calculation tool which is released to assist ship-owners in the ECA decision making. The first key insight...... much time their operated vessels navigate the ECA in the future....

  6. Buffer Zone Sign Template

    Science.gov (United States)

    The certified pesticide applicator is required to post a comparable sign, designating a buffer zone around the soil fumigant application block in order to control exposure risk. It must include the don't walk symbol, product name, and applicator contact.

  7. Buffer Zone, Nicosia

    OpenAIRE

    Sorensen, Marie Louise

    2010-01-01

    Images of the United Nations Buffer Zone or Green Line which has partitioned Cyprus since 1974 The research leading to these results has received funding from the European Community's Seventh Framework Programme [FP7/2007-2013] under grant agreement n° 217411.

  8. Arid Zone Hydrology

    Science.gov (United States)

    Arid zone hydrology encompasses a wide range of topics and hydro-meteorological and ecological characteristics. Although arid and semi-arid watersheds perform the same functions as those in humid environments, their hydrology and sediment transport characteristics cannot be readily predicted by inf...

  9. The IASB and FASB Convergence Process: Current Developments

    Directory of Open Access Journals (Sweden)

    Saher Aqel

    2012-04-01

    Full Text Available The importance of harmonization of accounting atandards is now widely accepted all over the world. The increased international movement of investments has strongly forces the harmonization of the various national accounting standards in a uniform financial reporting system accepted worldwide. Recently the Securities and Exchange Commission has agreed to remove the requirement international firms reporting under International Financial Reporting Standards (IFRS and listed in the U.S to provide reconciliation to U.S. Generally Accepted Accounting Principles (GAAP. This recent move of the Securities and Exchange Commission indicate that U.S. financial reporting is likely to converge with IFRS in the near future. The International Accounting Standards Board (IASB and the Financial Accounting Standards Board (FASB are currently working together so as to converge their existing accounting standards into a common set of international accounting standards. The objective of this paper is to discuss the FASB and IASB convergence process by addressing current developments regarding significant topics that were deemed critical to this convergence. The convergence of GAAP and IFRS seems inevitable. Mixed opinions have been voiced about this convergence process. Many have begun to consider obstacles that is possible to lay ahead as well as the possible costs and benefits of such a move to the IFRS .

  10. Worldwide Growth Convergence in the New Millennium: An Empirical Investigation

    Directory of Open Access Journals (Sweden)

    Lawrence J. Gomes

    2015-08-01

    Full Text Available Economic growth is an important ingredient for reducing poverty and achieving the Millennium Development Goals proposed by United Nations in 2000. Meeting these goals by the proposed 2015 target data depends on the ability of poor nations to grow their economies and improve their standards of living. Neoclassical and new growth theory suggests that there should be a negative relationship between a nation’s initial income and subsequent growth giving rise to either absolute convergence (income levels of all nations converge over time or conditional convergence (each nation converges to its unique steady-state income level. Using the most recent (2000-2013 World Bank data and cross-country regression techniques, I evaluated whether convergence has been occurring in the world in the last decade. My results showed a robust negative relationship between starting income level and subsequent growth. Savings and education were also associated with growth whereas trade was not. Overall, these results support the notion of convergence which is an encouraging finding as the world approaches the 2015 post-development agenda.

  11. Convergent evolution and divergent selection: lizards at the White Sands ecotone.

    Science.gov (United States)

    Rosenblum, Erica Bree

    2006-01-01

    Ecological transition zones, where organismal phenotypes result from a delicate balance between selection and migration, highlight the interplay of local adaptation and gene flow. Here, I study the response of an entire species assemblage to natural selection across a common ecotone. Three lizard species, distributed along a dramatic environmental gradient in substrate color, display convergent adaptation of blanched coloration on the gypsum dunes of White Sands National Monument. I investigate the role of gene flow in modulating phenotypic response to selection by quantifying color variation and genetic variation across the ecotone. I find species differences in degree of background matching and in genetic connectivity of populations across the ecotone. Differences among species in phenotypic response to selection scale precisely to levels of genetic isolation. Species with higher levels of gene flow across the ecotone exhibit less dramatic responses to selection. Results also reveal a strong signal of ecologically mediated divergence for White Sands lizards. For all species, phenotypic variation is better explained by habitat similarity than genetic similarity. Convergent evolution of blanched coloration at White Sands clearly reflects the action of strong divergent selection; however, adaptive response appears to be modulated by gene flow and demographic history and can be predicted by divergence-with-gene-flow models.

  12. Aeolian sedimentation in the middle buntsandstein in the eifel north-south depression zone: Summary of the variability of sedimentary processes in a buntsandstein erg as a base for evaluation of the mutual relationships between aeolian sand seas and fluvial river systems in the mid-european buntsandstein

    Science.gov (United States)

    Mader, Detlef

    The spectrum of aeolian depositional subenvironments in the upper Middle Buntsandstein Karlstal-Schichten sequence in the Eifel North-South-zone at the western margin of the Mid-European Triassic Basin comprises trains of larger and higher narrowly-spaced dunes in sand seas, isolated smaller and lower widely-spaced dunes in floodplains and interdune playas, dry interdune sheet sands, damp interdune adhesive sandflats, wet interdune playa lakes, rainfall runoff watercourses and ephemeral channels cutting through the dune belt, and deflation gravel lag veneers. Distinction of aeolian and fluvial sediments within the succession of closely intertonguing wind- and water-laid deposits is possible by independent analysis of the conventional criteria and the more modern stratification styles. Thick cross-bedded aeolian sand sequences originate as barchanoid-type dunes which accumulate and migrate in the regime of narrow to wide unimodal southeasterly to southwesterly trade winds in low northern palaeolatitude in summer when the intertropical convergence zone is shifted to the north. The predominantly transverse-ridge dunes accrete mainly by grainfall and subcritical climbing of wind ripples, subordinately also by grainflow interfingering with grainfall. Horizontal-laminated aeolian sands form as sand sheets in dry interdune playas by subcritical migration of wind ripple trains, rarely also by plane bed accretion. Thin cross-bedded dune sands or horizontal-laminated aeolian sands capping fluvial cyclothems originate by deflation of emerged alluvial bar sands during low-water stages and subsequent accumulation of the winnowed sand as widely-spaced dunelets or chains of wind ripples in desiccated parts of the adjoining floodplain. The aeolian sand layers at the base of lacustrine cyclothems record migration of isolated little dunes across the dry playa floor at the beginning of a wetting-upwards cyclothem, with the sand deriving from deflation of fluvial incursions or

  13. Evaluation of Ohio work zone speed zones process.

    Science.gov (United States)

    2014-06-01

    This report describes the methodology and results of analyses performed to determine the effectiveness of Ohio Department of Transportation processes for establishing work zone speed zones. Researchers observed motorists speed choice upstream of a...

  14. Empowerment Zones and Enterprise Districts - MDC_EnterpriseZone

    Data.gov (United States)

    NSGIC Local Govt | GIS Inventory — Polygon feature class of Miami Dade County Enterprise Zones. Enterprise Zones are special areas in the county where certain incentives from the State are available...

  15. Analysis of sponge zones for computational fluid mechanics

    International Nuclear Information System (INIS)

    Bodony, Daniel J.

    2006-01-01

    The use of sponge regions, or sponge zones, which add the forcing term -σ(q - q ref ) to the right-hand-side of the governing equations in computational fluid mechanics as an ad hoc boundary treatment is widespread. They are used to absorb and minimize reflections from computational boundaries and as forcing sponges to introduce prescribed disturbances into a calculation. A less common usage is as a means of extending a calculation from a smaller domain into a larger one, such as in computing the far-field sound generated in a localized region. By analogy to the penalty method of finite elements, the method is placed on a solid foundation, complete with estimates of convergence. The analysis generalizes the work of Israeli and Orszag [M. Israeli, S.A. Orszag, Approximation of radiation boundary conditions, J. Comp. Phys. 41 (1981) 115-135] and confirms their findings when applied as a special case to one-dimensional wave propagation in an absorbing sponge. It is found that the rate of convergence of the actual solution to the target solution, with an appropriate norm, is inversely proportional to the sponge strength. A detailed analysis for acoustic wave propagation in one-dimension verifies the convergence rate given by the general theory. The exponential point-wise convergence derived by Israeli and Orszag in the high-frequency limit is recovered and found to hold over all frequencies. A weakly nonlinear analysis of the method when applied to Burgers' equation shows similar convergence properties. Three numerical examples are given to confirm the analysis: the acoustic extension of a two-dimensional time-harmonic point source, the acoustic extension of a three-dimensional initial-value problem of a sound pulse, and the introduction of unstable eigenmodes from linear stability theory into a two-dimensional shear layer

  16. Special zone territory decontamination

    International Nuclear Information System (INIS)

    Samojlenko, Yu.N.; Golubev, V.V.

    1989-01-01

    Special zone is the Chernobyl' NPP operating site (OS). OS decontamination is described including reactor ruins from the accident moment. The process was begun from reactor bombardment with absorbing and filtering materials (sand, clay, lead, boron compounds). Then were produced soil shovelling, territory filling by dry concrete and laying concrete layer with thickness up to 300 mm. NPP room and equipment decontamination is described. 3 figs.; 3 tabs

  17. Radiant zone heated particulate filter

    Science.gov (United States)

    Gonze, Eugene V [Pinckney, MI

    2011-12-27

    A system includes a particulate matter (PM) filter including an upstream end for receiving exhaust gas and a downstream end. A radiant zoned heater includes N zones, where N is an integer greater than one, wherein each of the N zones includes M sub-zones, where M is an integer greater than or equal to one. A control module selectively activates at least a selected one of the N zones to initiate regeneration in downstream portions of the PM filter from the one of the N zones, restricts exhaust gas flow in a portion of the PM filter that corresponds to the selected one of the N zones, and deactivates non-selected ones of the N zones.

  18. Cornell Mixing Zone Expert System

    Science.gov (United States)

    This page provides an overview Cornell Mixing Zone Expert System water quality modeling and decision support system designed for environmental impact assessment of mixing zones resulting from wastewater discharge from point sources

  19. VT Data - Zoning 20070306, Marlboro

    Data.gov (United States)

    Vermont Center for Geographic Information — Zoning districts, Marlboro, Vermont. Surface water buffer overlay is in a separate shapefile. Data were originally created by WRC in 2005. Marlboro's zoning bylaw...

  20. Habitable Zones in the Universe

    OpenAIRE

    Gonzalez, G.

    2005-01-01

    Habitability varies dramatically with location and time in the universe. This was recognized centuries ago, but it was only in the last few decades that astronomers began to systematize the study of habitability. The introduction of the concept of the habitable zone was key to progress in this area. The habitable zone concept was first applied to the space around a star, now called the Circumstellar Habitable Zone. Recently, other, vastly broader, habitable zones have been proposed. We review...

  1. Active convergence between the Lesser and Greater Caucasus in Georgia: Constraints on the tectonic evolution of the Lesser-Greater Caucasus continental collision

    Science.gov (United States)

    Sokhadze, G.; Floyd, M.; Godoladze, T.; King, R.; Cowgill, E. S.; Javakhishvili, Z.; Hahubia, G.; Reilinger, R.

    2018-01-01

    We present and interpret newly determined site motions derived from GPS observations made from 2008 through 2016 in the Republic of Georgia, which constrain the rate and locus of active shortening in the Lesser-Greater Caucasus continental collision zone. Observation sites are located along two ∼160 km-long profiles crossing the Lesser-Greater Caucasus boundary zone: one crossing the Rioni Basin in western Georgia and the other crossing further east near the longitude of Tbilisi. Convergence across the Rioni Basin Profile occurs along the southern margin of the Greater Caucasus, near the surface trace of the north-dipping Main Caucasus Thrust Fault (MCTF) system, and is consistent with strain accumulation on the fault that generated the 1991 MW6.9 Racha earthquake. In contrast, convergence along the Tbilisi Profile occurs near Tbilisi and the northern boundary of the Lesser Caucasus (near the south-dipping Lesser Caucasus Thrust Fault), approximately 50-70 km south of the MCTF, which is inactive within the resolution of geodetic observations (< ± 0.5 mm/yr) at the location of the Tbilisi Profile. We suggest that the southward offset of convergence along strike of the range is related to the incipient collision of the Lesser-Greater Caucasus, and closing of the intervening Kura Basin, which is most advanced along this segment of the collision zone. The identification of active shortening near Tbilisi requires a reevaluation of seismic hazards in this area.

  2. Adaptive processes drive ecomorphological convergent evolution in antwrens (Thamnophilidae).

    Science.gov (United States)

    Bravo, Gustavo A; Remsen, J V; Brumfield, Robb T

    2014-10-01

    Phylogenetic niche conservatism (PNC) and convergence are contrasting evolutionary patterns that describe phenotypic similarity across independent lineages. Assessing whether and how adaptive processes give origin to these patterns represent a fundamental step toward understanding phenotypic evolution. Phylogenetic model-based approaches offer the opportunity not only to distinguish between PNC and convergence, but also to determine the extent that adaptive processes explain phenotypic similarity. The Myrmotherula complex in the Neotropical family Thamnophilidae is a polyphyletic group of sexually dimorphic small insectivorous forest birds that are relatively homogeneous in size and shape. Here, we integrate a comprehensive species-level molecular phylogeny of the Myrmotherula complex with morphometric and ecological data within a comparative framework to test whether phenotypic similarity is described by a pattern of PNC or convergence, and to identify evolutionary mechanisms underlying body size and shape evolution. We show that antwrens in the Myrmotherula complex represent distantly related clades that exhibit adaptive convergent evolution in body size and divergent evolution in body shape. Phenotypic similarity in the group is primarily driven by their tendency to converge toward smaller body sizes. Differences in body size and shape across lineages are associated to ecological and behavioral factors. © 2014 The Author(s). Evolution © 2014 The Society for the Study of Evolution.

  3. On the convergence of multigroup discrete-ordinates approximations

    International Nuclear Information System (INIS)

    Victory, H.D. Jr.; Allen, E.J.; Ganguly, K.

    1987-01-01

    Our analysis is divided into two distinct parts which we label for convenience as Part A and Part B. In Part A, we demonstrate that the multigroup discrete-ordinates approximations are well-defined and converge to the exact transport solution in any subcritical setting. For the most part, we focus on transport in two-dimensional Cartesian geometry. A Nystroem technique is used to extend the discrete ordinates multigroup approximates to all values of the angular and energy variables. Such an extension enables us to employ collectively compact operator theory to deduce stability and convergence of the approximates. In Part B, we perform a thorough convergence analysis for the multigroup discrete-ordinates method for an anisotropically-scattering subcritical medium in slab geometry. The diamond-difference and step-characteristic spatial approximation methods are each studied. The multigroup neutron fluxes are shown to converge in a Banach space setting under realistic smoothness conditions on the solution. This is the first thorough convergence analysis for the fully-discretized multigroup neutron transport equations

  4. Monte Carlo source convergence and the Whitesides problem

    International Nuclear Information System (INIS)

    Blomquist, R. N.

    2000-01-01

    The issue of fission source convergence in Monte Carlo eigenvalue calculations is of interest because of the potential consequences of erroneous criticality safety calculations. In this work, the authors compare two different techniques to improve the source convergence behavior of standard Monte Carlo calculations applied to challenging source convergence problems. The first method, super-history powering, attempts to avoid discarding important fission sites between generations by delaying stochastic sampling of the fission site bank until after several generations of multiplication. The second method, stratified sampling of the fission site bank, explicitly keeps the important sites even if conventional sampling would have eliminated them. The test problems are variants of Whitesides' Criticality of the World problem in which the fission site phase space was intentionally undersampled in order to induce marginally intolerable variability in local fission site populations. Three variants of the problem were studied, each with a different degree of coupling between fissionable pieces. Both the superhistory powering method and the stratified sampling method were shown to improve convergence behavior, although stratified sampling is more robust for the extreme case of no coupling. Neither algorithm completely eliminates the loss of the most important fissionable piece, and if coupling is absent, the lost piece cannot be recovered unless its sites from earlier generations have been retained. Finally, criteria for measuring source convergence reliability are proposed and applied to the test problems

  5. Convergence of logistics planning and execution in outsourcing

    Directory of Open Access Journals (Sweden)

    Angela A. D’amato

    2015-06-01

    Full Text Available Background: Logistics service providers (LSPs are becoming increasingly involved in their clients’ businesses. Beyond just providing vehicles and buildings, LSPs are now becoming involved with knowledge-related work that is connected to the traditional services provided. Objectives: To investigate the likelihood and potential value of LSPs extending their range of services to their clients by means of a convergence of planning and execution activities. Method: In the research through a literature review and empirical study presented here, attention is given to the practical impact that convergence planning and execution functions have on business success, as well as how selected clients of an LSP (referred to in this article as logistics company A or LCA perceive the impact of increased integration of LCA within its businesses. The results should assist LCA and other LSPs considering the same objective to ascertain the opportunities and key requirements associated with a strategy to converge planning and execution activities for their clients. Results: The study found that the vast majority of respondents see value in the convergence of planning and execution activities. Conclusion: Such convergence will be challenging, owing to the importance of the planning function for clients, as well as key collaborative and measurement requirements that will have to be put in place for successful business integration.

  6. Report on converging insert moulding with µ-IM

    DEFF Research Database (Denmark)

    Islam, Aminul

    moulding with µ-IM  Task 5.2.1 and COTECH demonstrator: guide line for 5PRC production based on the concept of Task 5.2.1 Information and results provided by this deliverable will be directly used for one of the COTECH demonstrators production which will call for convergent insert moulding with µ......Task 5.2.1 deals with the technical feasibility of converging the state-of-the-art µ IM process with insert moulding to offer a wide range of multi-material µ components. The main objective of this deliverable is to summarize state-of-the-art information and to make the guideline needed...... for the convergence. In particular the following aspects are summed up in the deliverable:  Need for converging insert moulding with µ-IM  Objectives and expected outcome from task 5.2.1  State-of-the-art micro insert moulding and different scenario of micro insert moulding  Challenges ahead of converging insert...

  7. Character convergence under competition for nutritionally essential resources.

    Science.gov (United States)

    Fox, Jeremy W; Vasseur, David A

    2008-11-01

    Resource competition is thought to drive divergence in resource use traits (character displacement) by generating selection favoring individuals able to use resources unavailable to others. However, this picture assumes nutritionally substitutable resources (e.g., different prey species). When species compete for nutritionally essential resources (e.g., different nutrients), theory predicts that selection drives character convergence. We used models of two species competing for two essential resources to address several issues not considered by existing theory. The models incorporated either slow evolutionary change in resource use traits or fast physiological or behavioral change. We report four major results. First, competition always generates character convergence, but differences in resource requirements prevent competitors from evolving identical resource use traits. Second, character convergence promotes coexistence. Competing species always attain resource use traits that allow coexistence, and adaptive trait change stabilizes the ecological equilibrium. In contrast, adaptation in allopatry never preadapts species to coexist in sympatry. Third, feedbacks between ecological dynamics and trait dynamics lead to surprising dynamical trajectories such as transient divergence in resource use traits followed by subsequent convergence. Fourth, under sufficiently slow trait change, ecological dynamics often drive one of the competitors to near extinction, which would prevent realization of long-term character convergence in practice.

  8. Convergence in carbon dioxide emissions among industrialised countries revisited

    Energy Technology Data Exchange (ETDEWEB)

    Romero-Avila, Diego [Pablo de Olavide University, Department of Economics, Carretera de Utrera, Km. 1, 41089, Seville (Spain)

    2008-09-15

    This paper examines the existence of stochastic and deterministic convergence of carbon dioxide (CO{sub 2}) emissions in 23 countries over the period 1960-2002. For that purpose, we conduct unit root testing by employing the recently developed panel stationarity test of Carrion-i-Silvestre et al. [Carrion-i-Silvestre, J-L, del Barrio-Castro, T., Lopez-Bazo, E., 2005. Breaking the panels: An application to the GDP per capita. Econometrics Journal 8, 159-175] which assumes a highly flexible trend function by incorporating an unknown number of structural breaks. We accommodate general forms of cross-sectional dependence as well as control for finite-sample bias through bootstrap methods. Overall, our analysis provides strong evidence supporting both stochastic and deterministic convergence in CO{sub 2} emissions, thus confirming Strazicich and List [Strazicich, M.C., List, J.A., 2003. Are CO{sub 2} emission levels converging among industrial countries? Environmental and Resource Economics 24, 263-271] and Westerlund and Basher [Westerlund, J., Basher, S.A., 2007. Testing for convergence in carbon dioxide emissions using a century of panel data. Environmental and Resource Economics, forthcoming] findings of convergence. (author)

  9. Convergence in carbon dioxide emissions among industrialised countries revisited

    International Nuclear Information System (INIS)

    Romero-Avila, Diego

    2008-01-01

    This paper examines the existence of stochastic and deterministic convergence of carbon dioxide (CO 2 ) emissions in 23 countries over the period 1960-2002. For that purpose, we conduct unit root testing by employing the recently developed panel stationarity test of Carrion-i-Silvestre et al. [Carrion-i-Silvestre, J-L, del Barrio-Castro, T., Lopez-Bazo, E., 2005. Breaking the panels: An application to the GDP per capita. Econometrics Journal 8, 159-175] which assumes a highly flexible trend function by incorporating an unknown number of structural breaks. We accommodate general forms of cross-sectional dependence as well as control for finite-sample bias through bootstrap methods. Overall, our analysis provides strong evidence supporting both stochastic and deterministic convergence in CO 2 emissions, thus confirming Strazicich and List [Strazicich, M.C., List, J.A., 2003. Are CO 2 emission levels converging among industrial countries? Environmental and Resource Economics 24, 263-271] and Westerlund and Basher [Westerlund, J., Basher, S.A., 2007. Testing for convergence in carbon dioxide emissions using a century of panel data. Environmental and Resource Economics, forthcoming] findings of convergence

  10. Convergence of trajectories in fractal interpolation of stochastic processes

    International Nuclear Information System (INIS)

    MaIysz, Robert

    2006-01-01

    The notion of fractal interpolation functions (FIFs) can be applied to stochastic processes. Such construction is especially useful for the class of α-self-similar processes with stationary increments and for the class of α-fractional Brownian motions. For these classes, convergence of the Minkowski dimension of the graphs in fractal interpolation of the Hausdorff dimension of the graph of original process was studied in [Herburt I, MaIysz R. On convergence of box dimensions of fractal interpolation stochastic processes. Demonstratio Math 2000;4:873-88.], [MaIysz R. A generalization of fractal interpolation stochastic processes to higher dimension. Fractals 2001;9:415-28.], and [Herburt I. Box dimension of interpolations of self-similar processes with stationary increments. Probab Math Statist 2001;21:171-8.]. We prove that trajectories of fractal interpolation stochastic processes converge to the trajectory of the original process. We also show that convergence of the trajectories in fractal interpolation of stochastic processes is equivalent to the convergence of trajectories in linear interpolation

  11. Post-convergence automatic differentiation of iterative schemes

    International Nuclear Information System (INIS)

    Azmy, Y.Y.

    1997-01-01

    A new approach for performing automatic differentiation (AD) of computer codes that embody an iterative procedure, based on differentiating a single additional iteration upon achieving convergence, is described and implemented. This post-convergence automatic differentiation (PAD) technique results in better accuracy of the computed derivatives, as it eliminates part of the derivatives convergence error, and a large reduction in execution time, especially when many iterations are required to achieve convergence. In addition, it provides a way to compute derivatives of the converged solution without having to repeat the entire iterative process every time new parameters are considered. These advantages are demonstrated and the PAD technique is validated via a set of three linear and nonlinear codes used to solve neutron transport and fluid flow problems. The PAD technique reduces the execution time over direct AD by a factor of up to 30 and improves the accuracy of the derivatives by up to two orders of magnitude. The PAD technique's biggest disadvantage lies in the necessity to compute the iterative map's Jacobian, which for large problems can be prohibitive. Methods are discussed to alleviate this difficulty

  12. Residential energy consumption: A convergence analysis across Chinese regions

    International Nuclear Information System (INIS)

    Herrerias, M.J.; Aller, Carlos; Ordóñez, Javier

    2017-01-01

    The process of urbanization and the raise of living standards in China have led an increasing trend in the patterns of residential consumption. Projections for the population growth rate in urban areas do not paint a very optimistic picture for energy conservation policies. In addition, the concentration of economic activities around coastal areas calls for new prospects to be formulated for energy policy. In this context, the objective of this paper is twofold. First, we analyse the effect of the urbanization process of the Chinese economy in terms of the long-run patterns of residential energy consumption at national level. By using the concept of club convergence, we examine whether electricity and coal consumption in rural and urban areas converge to the same long-run equilibrium or whether in fact they diverge. Second, the impact of the regional concentration of the economic activity on energy consumption patterns is also assessed by source of energy across Chinese regions from 1995 to 2011. Our results suggest that the process of urbanization has led to coal being replaced by electricity in urban residential energy consumption. In rural areas, the evidence is mixed. The club convergence analysis confirms that rural and urban residential energy consumption converge to different steady-states. At the regional level, we also confirm the effect of the regional concentration of economic activity on residential energy consumption. The existence of these regional clusters converging to different equilibrium levels is indicative of the need of regional-tailored set of energy policies in China.

  13. Analog models of convergence and divergence: perspectives of the tectonics of the Middle East

    Science.gov (United States)

    Mart, Yossi

    2010-05-01

    Three series of analog models of convergence and divergence of tectonic plates illuminate the possible tectonic processes that shaped the lithology of the Middle East since the early Miocene. The Mid-East geographic province extends from the Ionian Sea to the Arabian Sea, and comprises the Hellenic subduction zone, the Aegean back-arc basin, the motion of Anatolia southwestwards, the oblique collision of Arabia and Iran along the Zagros suture, and the continental break-up of the Gulf of Aden and the Red Sea. The tectonic evolution of all these diverse domains started in the Miocene nearly contemporaneously, and modeling suggests that the convergence and divergence, though derived from unrelated processes, their tectonics is intertwined. Centrifuge models of the initiation of subduction show the correlation between early subduction and the opening of its back-arc basin (Mart et al., 2005). The models emphasize the significance of extensive seawards roll-back of the deformation front when friction between the thrust slabs is reduced, and consequently, the pull within the overthrust slab that leads to its structural extension. That extension produced the Aegean domain with its volcanism and the exposure of its core complex, as well as the westwards displacement of Anatolia along the North and East Anatolian Faults. Sand-box models of oblique subduction, namely the gradual shift from subduction to collision along the convergence front, showed orthogonal patterns of extension in distal parts of the underthrust slab (Bellahsen et al., 2002). It is suggested that the extensional domains deflected the propagation of Carlsberg Ridge to swing 1200 and penetrate the Gulf of Aden in the early Miocene. The structural differences between the Gulf of Aden and the Red Sea can be accounted for by the results of sand-box experiments in oblique rifting (Mart and Dauteuil, 2000). The models suggest that oblique rifting, where the deviation from the normal extension was ca. 50, would

  14. A simple eigenfunction convergence acceleration method for Monte Carlo

    International Nuclear Information System (INIS)

    Booth, Thomas E.

    2011-01-01

    Monte Carlo transport codes typically use a power iteration method to obtain the fundamental eigenfunction. The standard convergence rate for the power iteration method is the ratio of the first two eigenvalues, that is, k_2/k_1. Modifications to the power method have accelerated the convergence by explicitly calculating the subdominant eigenfunctions as well as the fundamental. Calculating the subdominant eigenfunctions requires using particles of negative and positive weights and appropriately canceling the negative and positive weight particles. Incorporating both negative weights and a ± weight cancellation requires a significant change to current transport codes. This paper presents an alternative convergence acceleration method that does not require modifying the transport codes to deal with the problems associated with tracking and cancelling particles of ± weights. Instead, only positive weights are used in the acceleration method. (author)

  15. Shock wave convergence in water with parabolic wall boundaries

    International Nuclear Information System (INIS)

    Yanuka, D.; Shafer, D.; Krasik, Ya.

    2015-01-01

    The convergence of shock waves in water, where the cross section of the boundaries between which the shock wave propagates is either straight or parabolic, was studied. The shock wave was generated by underwater electrical explosions of planar Cu wire arrays using a high-current generator with a peak output current of ∼45 kA and rise time of ∼80 ns. The boundaries of the walls between which the shock wave propagates were symmetric along the z axis, which is defined by the direction of the exploding wires. It was shown that with walls having a parabolic cross section, the shock waves converge faster and the pressure in the vicinity of the line of convergence, calculated by two-dimensional hydrodynamic simulations coupled with the equations of state of water and copper, is also larger

  16. ‘The Schneiderverse’: Nickelodeon, Convergent Television and Transmedia Storytelling

    Directory of Open Access Journals (Sweden)

    Helena Louise Dare-Edwards

    2014-12-01

    Full Text Available This article will analyse the textual features of two recent and successful Nickelodeon shows, both of which incorporate digital and social technologies into their sitcom-style format. Aimed at a tween-girl audience, these ‘convergence comedies’ complicate traditional notions of media spectatorship and the distinctions between media producers and consumers as audiences are invited to participate in the processes of production. While media convergence is built into the visual style of both shows, the shows themselves converge to create a shared fictional world, dubbed the ‘Schneiderverse’, which traverses the boundary between the real and the fictional. It will be considered how the audience’s media experience could be enriched through immersion in the online spaces associated with the texts.

  17. Computational Investigations in Rectangular Convergent and Divergent Ribbed Channels

    Science.gov (United States)

    Sivakumar, Karthikeyan; Kulasekharan, N.; Natarajan, E.

    2018-05-01

    Computational investigations on the rib turbulated flow inside a convergent and divergent rectangular channel with square ribs of different rib heights and different Reynolds numbers (Re=20,000, 40,000 and 60,000). The ribs were arranged in a staggered fashion between the upper and lower surfaces of the test section. Computational investigations are carried out using computational fluid dynamic software ANSYS Fluent 14.0. Suitable solver settings like turbulence models were identified from the literature and the boundary conditions for the simulations on a solution of independent grid. Computations were carried out for both convergent and divergent channels with 0 (smooth duct), 1.5, 3, 6, 9 and 12 mm rib heights, to identify the ribbed channel with optimal performance, assessed using a thermo hydraulic performance parameter. The convergent and divergent rectangular channels show higher Nu values than the standard correlation values.

  18. Slab geometry spatial discretization schemes with infinite-order convergence

    International Nuclear Information System (INIS)

    Adams, M.L.; Martin, W.R.

    1985-01-01

    Spatial discretization schemes for the slab geometry discrete ordinates transport equation have received considerable attention in the past several years, with particular interest shown in developing methods that are more computationally efficient that standard schemes. Here the authors apply to the discrete ordinates equations a spectral method that is significantly more efficient than previously proposed schemes for high-accuracy calculations of homogeneous problems. This is a direct consequence of the exponential (infinite-order) convergence of spectral methods for problems with every smooth solutions. For heterogeneous problems where smooth solutions do not exist and exponential convergence is not observed with spectral methods, a spectral element method is proposed which does exhibit exponential convergence

  19. Romania’s Accession to Second Modernity. Potential of Convergence

    Directory of Open Access Journals (Sweden)

    Marin Dinu

    2006-06-01

    Full Text Available This paper analyses Romanian economy facing with European integration process at 2007. The Romanian economy advanced the development prudent macroeconomics policies and implement structural reforms in the market for goods, labor and financial products. We identify in this study the principal conditionalities for the admittance in European Union. The nominal and real convergence must be touched faster because this process supposes stability prices, the financial soundness indicators, the need to stabilize exchange rate. In addition, the real convergence with European Union is very important. First, we analyze the strategic errors of the Romanian authorities in transition period. Second, our study focuses on current challenges and makes suggestions for change the modernization process. Can Romanian economy obtain a grow faster convergence? Is the strategy of Romanian economy optimal?

  20. Convergence and determinants of health expenditures in OECD countries.

    Science.gov (United States)

    Nghiem, Son Hong; Connelly, Luke Brian

    2017-08-17

    This study examines the trend and determinants of health expenditures in OECD countries over the 1975-2004 period. Based on recent developments in the economic growth literature we propose and test the hypothesis that health care expenditures in countries of similar economic development level may converge. We hypothesise that the main drivers for growth in health care costs include: aging population, technological progress and health insurance. The results reveal no evidence that health expenditures among OECD countries converge. Nevertheless, there is evidence of convergence among three sub-groups of countries. We found that the main driver of health expenditure is technological progress. Our results also suggest that health care is a (national) necessity, not a luxury good as some other studies in this field have found.