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Sample records for 233u self-fueling regime

  1. Extraction of 229Th From 233U Solution

    Institute of Scientific and Technical Information of China (English)

    XIAO; Guo-ping; ZHAO; Li-fei

    2013-01-01

    A two-step separation procedure for preparation of 229Th tracer from 233U was developed using CL-TBP and TEVA extraction chromatography.The decontamination factor of uranium from thorium is larger than 4.6×106.After separation,the content of 233U in uranium fraction was measured by ID-ICP-MS,

  2. Repository criticality control for {sup 233}U using depleted uranium

    Energy Technology Data Exchange (ETDEWEB)

    Forsberg, C.W.; Elam, K.R.; Hopper, C.M.

    1999-07-01

    The US is evaluating methods for the disposition of excess weapons-usable {sup 233}U, including disposal in a repository. Isotopic dilution studies were undertaken to determine how much depleted uranium (DU) would need to be added to the {sup 233}U to minimize the potential for nuclear criticality in a repository. Numerical evaluations were conducted to determine the nuclear equivalence of different {sup 235}U enrichments to {sup 233}U isotopically diluted with DU containing 0.2 wt% {sup 235}U. A homogeneous system of silicon dioxide, water, {sup 233}U, and DU, in which the ratio of each component was varied, was used to determine the conditions of maximum nuclear reactivity. In terms of preventing nuclear criticality in a repository, there are three important limits from these calculations. 1. Criticality safe in any nonnuclear system: The required isotopic dilution to ensure criticality under all conditions, except in the presence of man-made nuclear materials (beryllium, etc.), is {approximately}1.0% {sup 235}U in {sup 238}U. The equivalent {sup 233}U enrichment level is 0.53 wt% {sup 233}U in DU. 2. Critically safe in natural systems: The lowest {sup 235}U enrichment found in a natural reactor at shutdown was {approximately}1.3%. French studies, based on the characteristics of natural uranium ore bodies, indicate that a minimum enrichment of {approximately}1.28% {sup 235}U is required for criticality. These data suggest that nuclear criticality from migrating uranium is not realistic unless the {sup 235}U enrichments exceed {approximately}1.3%, which is a result that is equivalent to 0.72% {sup 233}U in DU. 3. Criticality safety equivalent to light water reactor (LWR) spent nuclear fuel (SNF): The {sup 233}U can be diluted with DU so that the uranium criticality characteristics match SNF uranium. Whatever repository criticality controls are used for SNF can then be used for {sup 233}U. The average LWR SNF assay (after decay of plutonium isotopes to uranium

  3. Repository criticality control for 233U using depleted uranium

    International Nuclear Information System (INIS)

    The US is evaluating methods for the disposition of excess weapons-usable 233U, including disposal in a repository. Isotopic dilution studies were undertaken to determine how much depleted uranium (DU) would need to be added to the 233U to minimize the potential for nuclear criticality in a repository. Numerical evaluations were conducted to determine the nuclear equivalence of different 235U enrichments to 233U isotopically diluted with DU containing 0.2 wt% 235U. A homogeneous system of silicon dioxide, water, 233U, and DU, in which the ratio of each component was varied, was used to determine the conditions of maximum nuclear reactivity. In terms of preventing nuclear criticality in a repository, there are three important limits from these calculations. 1. Criticality safe in any nonnuclear system: The required isotopic dilution to ensure criticality under all conditions, except in the presence of man-made nuclear materials (beryllium, etc.), is ≅1.0% 235U in 238U. The equivalent 233U enrichment level is 0.53 wt% 233U in DU. 2. Critically safe in natural systems: The lowest 235U enrichment found in a natural reactor at shutdown was approximately1.3%. French studies, based on the characteristics of natural uranium ore bodies, indicate that a minimum enrichment of approximately1.28% 235U is required for criticality. These data suggest that nuclear criticality from migrating uranium is not realistic unless the 235U enrichments exceed approximately1.3%, which is a result that is equivalent to 0.72% 233U in DU. 3. Criticality safety equivalent to light water reactor (LWR) spent nuclear fuel (SNF): The 233U can be diluted with DU so that the uranium criticality characteristics match SNF uranium. Whatever repository criticality controls are used for SNF can then be used for 233U. The average LWR SNF assay (after decay of plutonium isotopes to uranium isotopes) is 1.5% 235U equivalent in 238U. This is equivalent to diluting 233U to 0.81% in DU

  4. Experimental 233U nondestructive assay with a random driver

    International Nuclear Information System (INIS)

    Nondestructive assay (NDA) of 233U in quantities up to 15 grams containing 7 ppM 232U age 2 years was investigated with a random driver. A passive singles counting technique showed a reproducibility within 0.2% at the 95% confidence level. This technique would be applicable throughout a process in which all of the 233U had the same 232U content at the same age. Where the 232U content varies, determination of 233U fissile content would require active NDA. Active coincidence counting utilizing a 238Pu, Li neutron source and a plastic scintillator detector system showed a reproducibility limit within 15% at the 95% confidence limit. The active technique was found to be very dependent on the detector system resolving time in order to make proper random coincidence corrections associated with the high gamma activity from the 232U decay chain

  5. Updated and revised neutron reaction data for 233U

    Institute of Scientific and Technical Information of China (English)

    YU Bao-Sheng; CHEN Guo-Chang; ZHANG Hua; CAO Wen-Tian; TANG Guo-You; TAO Xi

    2013-01-01

    A complete set of n+233U neutron reaction data from 10-5 eV-20 MeV is updated and revised based on the evaluated experimental data and the feedback information of various benchmark tests.The main revised quantities are nubars,cross sections as well as angular distributions,etc.The benchmark tests indicate that the present evaluated data achieve very promising results.

  6. Thermal Stabilization of 233UO2, 233UO3, and 233U3O8

    International Nuclear Information System (INIS)

    This report identifies an appropriate thermal stabilization temperature for 233U oxides. The temperature is chosen principally on the basis of eliminating moisture and other residual volatiles. This report supports the U. S. Department of Energy (DOE) Standard for safe storage of 233U (DOE 2000), written as part of the response to Recommendation 97-1 of the Defense Nuclear Facilities Safety Board (DNFSB), addressing safe storage of 233U

  7. Isotopic dilution of 233U with depleted uranium for criticality safety in processing and disposal

    International Nuclear Information System (INIS)

    The disposal of excess 233U as waste is being considered. Because 233U is a fissile material, a key requirement for processing 233U to a final waste form and disposing of it is the avoidance of nuclear criticality. For many processing and disposal options, isotopic dilution is the most feasible and preferred option to avoid nuclear criticality. Isotopic dilution is dilution of fissile 233U with nonfissile 238U. The use of isotopic dilution removes any need to control nuclear criticality in process or disposal facilities through geometry or chemical composition. Isotopic dilution allows the use of existing waste management facilities that are not designed for significant quantities of fissile materials to be used for processing and disposing of 233U. The amount of isotopic dilution required to reduce criticality concerns to reasonable levels was determined in this study to be approximately 0.53 wt % 233U. The numerical calculations used to define this limit consisted of a homogeneous system of silicon dioxide (SiO2), water (H2O), 233U and depleted uranium (DU) in which the ratio of each component was varied to learn the conditions of maximum nuclear reactivity. About 188 parts of DU (0.2 wt % 235U) are required to dilute 1 part of 233U to this limit in a water-moderated system with no SiO2 present. Thus for the U.S. inventory of 233U, several hundred metric tons of DU would be required for isotopic dilution

  8. Renewal and Modified Evaluation Data of ~(233)U in CENDL_-3.1

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    A complete set of evaluated neutron nuclear data of 233U was preformed before 2000, and released in 2009. The status of the published nuclear data 233U in CENDL-3.1 is in some cases not up to the requirements. As the recent experimental data

  9. Separation and estimation of 229Th and 233U by alpha and gamma ray spectrometric technique

    International Nuclear Information System (INIS)

    The individual estimation of 233U and 229Th in a plancheted source made out of liquid sample were done by using an alpha and γ-ray spectrometric techniques. Estimation of 229Th in the plancheted source was done by γ-ray spectrometry and 233U by alpha spectrometry after subtracting the estimated amount of 229Th. In spite of the same alpha energy of 4.8 MeV, the individual estimation of 233U and 229Th based on present technique is superior to conventional techniques and important in the 232Th-233U fuel reprocessing cycle of AHWR and ADSs. The activity of 229Th was also radiochemically separated from its parent activity of 233U by using an ion exchange resin and the purity was checked by the above mentioned technique. (author)

  10. Interim assessment of the denatured 233U fuel cycle: feasibility and nonproliferation characteristics

    International Nuclear Information System (INIS)

    A fuel cycle that employs 233U denatured with 238U and mixed with thorium fertile material is examined with respect to its proliferation-resistance characteristics and its technical and economic feasibility. The rationale for considering the denatured 233U fuel cycle is presented, and the impact of the denatured fuel on the performance of Light-Water Reactors, Spectral-Shift-Controlled Reactors, Gas-Cooled Reactors, Heavy-Water Reactors, and Fast Breeder Reactors is discussed. The scope of the R, D and D programs to commercialize these reactors and their associated fuel cycles is also summarized and the resource requirements and economics of denatured 233U cycles are compared to those of the conventional Pu/U cycle. In addition, several nuclear power systems that employ denatured 233U fuel and are based on the energy center concept are evaluated. Under this concept, dispersed power reactors fueled with denatured or low-enriched uranium fuel are supported by secure energy centers in which sensitive activities of the nuclear cycle are performed. These activities include 233U production by Pu-fueled transmuters (thermal or fast reactors) and reprocessing. A summary chapter presents the most significant conclusions from the study and recommends areas for future work

  11. Interim assessment of the denatured /sup 233/U fuel cycle: feasibility and nonproliferation characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Abbott, L.S.; Bartine, D.E.; Burns, T.J. (eds.)

    1978-12-01

    A fuel cycle that employs /sup 233/U denatured with /sup 238/U and mixed with thorium fertile material is examined with respect to its proliferation-resistance characteristics and its technical and economic feasibility. The rationale for considering the denatured /sup 233/U fuel cycle is presented, and the impact of the denatured fuel on the performance of Light-Water Reactors, Spectral-Shift-Controlled Reactors, Gas-Cooled Reactors, Heavy-Water Reactors, and Fast Breeder Reactors is discussed. The scope of the R, D and D programs to commercialize these reactors and their associated fuel cycles is also summarized and the resource requirements and economics of denatured /sup 233/U cycles are compared to those of the conventional Pu/U cycle. In addition, several nuclear power systems that employ denatured /sup 233/U fuel and are based on the energy center concept are evaluated. Under this concept, dispersed power reactors fueled with denatured or low-enriched uranium fuel are supported by secure energy centers in which sensitive activities of the nuclear cycle are performed. These activities include /sup 233/U production by Pu-fueled transmuters (thermal or fast reactors) and reprocessing. A summary chapter presents the most significant conclusions from the study and recommends areas for future work.

  12. Breeding of 233U in the thorium-uranium fuel cycle in VVER reactors using heavy water

    Science.gov (United States)

    Marshalkin, V. E.; Povyshev, V. M.

    2015-12-01

    A method is proposed for achieving optimal neutron kinetics and efficient isotope transmutation in the 233U-232Th oxide fuel of water-moderated reactors with variable water composition (D2O, H2O) that ensures breeding of the 233U and 235U isotopes. The method is comparatively simple to implement.

  13. Compilation of criticality data involving thorium or 233U and light water moderation

    Energy Technology Data Exchange (ETDEWEB)

    Gore, B.F.

    1978-07-01

    The literature has been searched for criticality data for light water moderated systems which contain thorium or /sup 233/U, and data found are compiled herein. They are from critical experiments, extrapolations, and exponential experiments performed with homogeneous solutions and metal spheres of /sup 233/U; with lattices of fuel rods containing highly enriched /sup 235/UO/sub 2/ - ThO/sub 2/ and /sup 233/UO/sub 2/ - ThO/sub 2/; and with arrays of cyclinders of /sup 233/U solutions. The extent of existing criticality data has been compared with that necessary to implement a thorium-based fuel cycle. No experiments have been performed with any solutions containing thorium. Neither do data exist for homogeneous /sup 233/U systems with H/U < 34, except for solid metal systems. Arrays of solution cylinders up to 3 x 3 x 3 have been studied. Data for solutions containing fixed or soluble poisons are very limited. All critical lattices using /sup 233/UO/sub 2/ - ThO/sub 2/ fuels (LWBR program) were zoned radially, and in most cases axially also. Only lattice experiments using /sup 235/UO/sub 2/ - ThO/sub 2/ fuels have been performed using a single fuel rod type. Critical lattices of /sup 235/UO/sub 2/ - ThO/sub 2/ rods poisoned with boron have been measured, but only exponential experiments have been performed using boron-poisoned lattices of /sup 233/UO/sub 2/ - ThO/sub 2/ rods. No criticality data exist for denatured fuels (containing significant amounts of /sup 238/U) in either solution or lattice configurations.

  14. Final purification of 233U from thorium by Dowex 50x4 in Thorex process

    International Nuclear Information System (INIS)

    The 233U product obtained after a single cycle 5% tributyl phosphate/shell sol T extraction, scrubbing and stripping often contains significant amount of thorium as impurity. Further purification is normally carried out using ion exchange. The present paper summarises the results of the studies carried out to find out the various factors responsible for the extraordinary binding of thorium ion at the exchanger site while exploring the possibility of eluting total thorium using HNO3 alone

  15. Investigations on production of 233U using few pin thoria in existing PHWRs

    International Nuclear Information System (INIS)

    Thorium is not a fissile material and cannot be used to either start or sustain the chain reaction. Therefore, a reactor using thorium would also need either enriched uranium or plutonium to sustain the chain reaction until enough of the thorium has converted to fissile 233U. In order to retrieve and reprocess the irradiated fuel, the bundle is designed with few thoria pins and rest SEU pins. In the present study, different pin configurations of thoria in 19 and 37 element fuel clusters of Indian PHWRs have been considered. The lattice calculations have been done using the multi-group transport theory code CLUB. The variations of k∞ versus burn up are depicted in the paper. The production of 233U (considering also the decay of 233Pa into 233U) is also shown. Average discharge burn ups of the order 20 and 17 GWd/Te can be achieved with the use of thoria pins in 19 and 37 element fuel clusters respectively with appropriate bundle shift scheme. Derating of power is required during operation because of bundle power restrictions. It is found that 1 pin thoria configuration is preferable from the point of view of fuel requirements and power reduction consideration. Since 37 element fuel cluster used in 540 MWe PHWR fuel has large margins in bundle power, the restriction in power operation is much less than 19 element fuel cluster used in 220 MWe PHWR

  16. Criticality safety validation: Simple geometry, single unit {sup 233}U systems

    Energy Technology Data Exchange (ETDEWEB)

    Putman, V.L.

    1997-06-01

    Typically used LMITCO criticality safety computational methods are evaluated for suitability when applied to INEEL {sup 233}U systems which reasonably can be modeled as simple-geometry, single-unit systems. Sixty-seven critical experiments of uranium highly enriched in {sup 233}U, including 57 aqueous solution, thermal-energy systems and 10 metal, fast-energy systems, were modeled. These experiments include 41 cylindrical and 26 spherical cores, and 41 reflected and 26 unreflected systems. No experiments were found for intermediate-neutron-energy ranges, or with interstitial non-hydrogenous materials typical of waste systems, mixed {sup 233}U and plutonium, or reflectors such as steel, lead, or concrete. No simple geometry experiments were found with cubic or annular cores, or approximating infinite sea systems. Calculations were performed with various tools and methodologies. Nine cross-section libraries, based on ENDF/B-IV, -V, or -VI.2, or on Hansen-Roach source data, were used with cross-section processing methods of MCNP or SCALE. The k{sub eff} calculations were performed with neutral-particle transport and Monte Carlo methods of criticality codes DANT, MCNP 4A, and KENO Va.

  17. Technical Competencies for the Safe Interim Storage and Management of 233U at U.S. Department of Energy Facilities

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, D.O.; Krichinsky, A.M.; Laughlin, S.S.; Van Essen, D.C.; Yong, L.K.

    1999-02-17

    Uranium-233 (with concomitant {sup 232}U) is a man-made fissile isotope of uranium with unique nuclear characteristics which require high-integrity alpha containment biological shielding, and remote handling. The special handling considerations and the fact that much of the {sup 233}U processing and large-scale handling was performed over a decade ago underscore the importance of identifying the people within the DOE complex who are currently working with or have worked with {sup 233}U. The availability of these key personnel is important in ensuring safe interim storage, management and ultimate disposition of {sup 233}U at DOE facilities. Significant programs are ongoing at several DOE sites with actinides. The properties of these actinide materials require many of the same types of facilities and handling expertise as does {sup 233}U.

  18. Neutron inelastic-scattering cross sections of 232Th, 233U, 235U, 238U, 239Pu and 240Pu

    International Nuclear Information System (INIS)

    Differential-neutron-emission cross sections of 232Th, 233U, 235U, 238U, 239Pu and 240Pu are measured between approx. = 1.0 and 3.5 MeV with the angle and magnitude detail needed to provide angle-integrated emission cross sections to approx. 232Th, 233U, 235U and 238U inelastic-scattering values, poor agreement is observed for 240Pu, and a serious discrepancy exists in the case of 239Pu

  19. Simultaneous measurement of the neutron capture and fission yields of {sup 233}U

    Energy Technology Data Exchange (ETDEWEB)

    Berthoumieux, E.; Abbondanno, U.; Aerts, G.; Alvarez, H.A.; Alvarez-Velarde, F.A.; Andriamonje, S.; Andrzejewski, J.; Assimakopoulos, P.; Audouin, L.; Badurek, G.; Baumann, P.; Becvar, F.; Calvino, F.; Calviani, M.; Cano Ott, D.; Capote, R.; Carrapic, C.; Cennini, P.; Chepel, V.; Chiaveri, E.; Colonna, N.; Cortes, G.; Couture, A.; Cox, J.; Dahlfors, M.; David, S.; Dillmann, I.; Domingo-Pardo, C.; Dridi, W.; Duran, I.; Eleftheriadis, C.; Embid-Segura, M.; Ferrant, L.; Ferrari, A.; Ferreira-Marques, R.; Fujii, K.; Furman, W.; Goncalves, I.; Gonzalez-Romero, E.; Gramegna, F.; Guerrero, C.; Gunsing, F.; Haas, B.; Haight, R.; Heil, M.; Herrera-Martinez, A.; Igashira, M.; Jericha, E.; Kappeler, F.; Kadi, Y.; Karadimos, D.; Karamanis, D.; Kerveno, M.; Koehler, P.; Kossionides, E.; Krticka, M.; Lampoudis, C.; Leeb, H.; Lindote, A.; Lopes, I.; Lozano, M.; Lukic, S.; Marganiec, J.; Marrone, S.; Martinez, T.; Massimi, C.; Mastinu, P.; Mengoni, A.; Milazzo, P.M.; Moreau, C.; Mosconi, M.; Neves, F.; Oberhummer, H.; O' Brien, S.; Pancin, J.; Papachristodoulou, C.; Papadopoulos, C.; Paradela, C.; Patronis, N.; Pavlik, A.; Pavlopoulos, P.; Perrot, L.; Pigni, M.T.; Plag, R.; Plompen, A.; Plukis, A.; Poch, A.; Praena, J.; Pretel, C.; Quesada, J.; Rauscher, T.; Reifarth, R.; Rubbia, C.; Rudolf, G.; Rullhusen, P.; Salgado, J.; Santos, C.; Sarchiapone, L.; Savvidis, I.; Stephan, C.; Tagliente, G.; Tain, J.L.; Tassan-Got, L.; Tavora, L.; Terlizzi, R.; Vannini, G.; Vaz, P.; Ventura, A.; Villamarin, D.; Vincente, M.C.; Vlachoudis, V.; Vlastou, R.; Voss, F.; Walter, S.; Wiescher, M.; Wisshak, K

    2008-07-01

    We have measured the neutron capture and fission cross section of {sup 233}U at the neutron time-of-flight facility n-TOF at CERN in the energy range from 1 eV to 1 MeV with high accuracy by using a high performance 4{pi} BaF{sub 2} Total Absorption Calorimeter (TAC) as a detection device. The method, based on the shape analysis of the TAC energy response, allowing to disentangle between {gamma}'s originating from fission and capture will be presented as well as the first very preliminary results. (authors)

  20. Shutdown margin for high conversion BWRs operating in Th-{sup 233}U fuel cycle

    Energy Technology Data Exchange (ETDEWEB)

    Shaposhnik, Y., E-mail: shaposhy@bgu.ac.il [NRCN – Nuclear Research Center Negev, POB 9001, Beer Sheva 84190 (Israel); Department of Nuclear Engineering, Ben-Gurion University of the Negev, POB 653, Beer Sheva 84105 (Israel); Shwageraus, E. [Department of Nuclear Engineering, Ben-Gurion University of the Negev, POB 653, Beer Sheva 84105 (Israel); Elias, E. [Faculty of Mechanical Engineering, Technion – Israel Institute of Technology, Technion City 32000, Haifa (Israel)

    2014-09-15

    Highlights: • BWR core operating in a closed self-sustainable Th-{sup 233}U fuel cycle. • Shutdown Margin in Th-RBWR design. • Fully coupled MC with fuel depletion and thermo-hydraulic feedback modules. • Thermal–hydraulic analysis includes MCPR observation. - Abstract: Several reactivity control system design options are explored in order to satisfy shutdown margin (SDM) requirements in a high conversion BWRs operating in Th-{sup 233}U fuel cycle (Th-RBWR). The studied core has an axially heterogeneous fuel assembly structure with a single fissile zone “sandwiched” between two fertile blanket zones. The utilization of an originally suggested RBWR Y-shape control rod in Th-RBWR is shown to be insufficient for maintaining adequate SDM to balance the high negative reactivity feedbacks, while maintaining fuel breeding potential, core power rating, and minimum Critical Power Ratio (CPR). Implementation of alternative reactivity control materials, reducing axial leakage through non-uniform enrichment distribution, use of burnable poisons, reducing number of pins as well as increasing pin diameter are also shown to be incapable of meeting the SDM requirements. Instead, an alternative assembly design, based on Rod Cluster Control Assembly with absorber rods was investigated. This design matches the reference ABWR core power and has adequate shutdown margin. The new concept was modeled as a single three-dimensional fuel assembly having reflective radial boundaries, using the BGCore system, which consists of the MCNP code coupled with fuel depletion and thermo-hydraulic feedback modules.

  1. Shutdown Margin for High Conversion BWRs Operating in Th-233U Fuel Cycle

    CERN Document Server

    Shaposhnik, Yaniv; Elias, Ezra

    2013-01-01

    Several reactivity control system design options are explored in order to satisfy shutdown margin (SDM) requirements in a high conversion BWRs operating in Th-233U fuel cycle (Th-RBWR). The studied has an axially heterogeneous fuel assembly structure with a single fissile zone sandwiched between two fertile blanket zones. The utilization of an originally suggested RBWR Y-shape control rod in Th-RBWR is shown to be insufficient for maintaining adequate SDM to balance the high negative reactivity feedbacks, while maintaining fuel breeding potential, core power rating, and minimum Critical Power Ratio (CPR). Instead, an alternative assembly design, also relying on heterogeneous fuel zoning, is proposed for achieving fissile inventory ratio (FIR) above unity, adequate SDM and meeting minimum CPR limit at thermal core output matching the ABWR power. The new concept was modeled as a single 3-dimensional fuel assembly having reflective radial boundaries, using the BGCore system, which consists of the MCNP code coupl...

  2. Fuel utilization improvement in PWRs using the denatured /sup 233/U-Th cycle

    Energy Technology Data Exchange (ETDEWEB)

    Jones, H.M.; Schwenk, G.A.; Toops, E.C.; Yotinen, V.O.

    1980-06-01

    A number of changes in PWR core design and/or operating strategy were evaluated to assess the fuel utilization improvement achievable by their implementation in a PWR using thorium-based fuel and operating in a recycle mode. The reference PWR for this study was identical to the B and W Standard Plant except that the fuel pellets were of denatured (/sup 233/U//sup 238/U-Th)O/sub 2/. An initial scoping study identified the three most promising improvement concepts as (1) a very tight lattice, (2) thorium blankets, and (3) ThO/sub 2/ rods placed in available guide tubes. A conceptual core design incorporating these changes was then developed, and the fuel utilization of this modified design was compared with that of the reference case.

  3. 233U mass yield measurements around and within the symmetry region with the ILL Lohengrin spectrometer

    Science.gov (United States)

    Chebboubi, A.; Kessedjian, G.; Sage, C.; Bernard, D.; Blanc, A.; Faust, H.; Köster, U.; Litaize, O.; Mutti, P.; Serot, O.

    2016-03-01

    The study of fission yields has a major impact on the characterization and understanding of the fission process and is mandatory for reactor applications. The LPSC in collaboration with ILL and CEA has developed a measurement program on fission fragment distributions at the Lohengrin spectrometer of the ILL, with a special focus on the masses constituting the heavy peak. We will present in this paper our measurement of the very low fission yields in the symmetry mass region and the heavy mass wing of the distribution for 233U thermal neutron induced fission. The difficulty due to the strong contamination by other masses with much higher yields will be addressed in the form of a new analysis method featuring the required contaminant correction. The apparition of structures in the kinetic energy distributions and possible interpretations will be discussed, such as a possible evidence of fission modes.

  4. Breeding of 233U in the thorium–uranium fuel cycle in VVER reactors using heavy water

    International Nuclear Information System (INIS)

    A method is proposed for achieving optimal neutron kinetics and efficient isotope transmutation in the 233U–232Th oxide fuel of water-moderated reactors with variable water composition (D2O, H2O) that ensures breeding of the 233U and 235U isotopes. The method is comparatively simple to implement

  5. Breeding of {sup 233}U in the thorium–uranium fuel cycle in VVER reactors using heavy water

    Energy Technology Data Exchange (ETDEWEB)

    Marshalkin, V. E., E-mail: marshalkin@vniief.ru; Povyshev, V. M. [Russian Federal Nuclear Center All-Russian Research Institute of Experimental Physics (VNIIEF) (Russian Federation)

    2015-12-15

    A method is proposed for achieving optimal neutron kinetics and efficient isotope transmutation in the {sup 233}U–{sup 232}Th oxide fuel of water-moderated reactors with variable water composition (D{sub 2}O, H{sub 2}O) that ensures breeding of the {sup 233}U and {sup 235}U isotopes. The method is comparatively simple to implement.

  6. Measurements of neutron induced capture and fission reactions on $^{233}$ U (EAR1)

    CERN Multimedia

    The $^{233}$U plays the essential role of ssile nucleus in the Th-U fuel cycle, which has been proposed as a safer and cleaner alternative to the U-Pu fuel cycle. Considered the scarce data available to assess the capture cross section, a measurement was proposed and successfully performed at the n_TOF facility at CERN using the 4$\\pi$ Total Absorp- tion Calorimeter (TAC). The measurement was extremely dicult due to the need to accurately distinguish between capture and fission $\\gamma$-rays without any additional discrim-ination tool and the measured capture cross section showed a signicant disagreement in magnitude when compared with the ENDF/B-VII.1 library despite the agreement in shape. We propose a new measurement that is aimed at providing a higher level of dis-crimination between competing nuclear reactions, to extend the neutron energy range and to obtain more precise and accurate data, thus fullling the demands of the "NEA High Priority Nuclear Data Request List". The setup is envisaged as a combin...

  7. Comparison on Decay Process of Explosive Products for 233U and Weapon-grade Plutonium%233U 和武器级钚的爆炸产物放射性衰变过程的比较

    Institute of Scientific and Technical Information of China (English)

    沈姚崧; 刘成安

    2000-01-01

    233U 模型和武器级钚模型核爆炸后爆炸产物的放射性活度、生物潜在危害因子和能量沉积等量进行了比较, 分析了武器级钚模型中上述各量的演化情况.

  8. Amster: a molten-salt reactor concept generating its own 233U and incinerating transuranium elements

    International Nuclear Information System (INIS)

    In the coming century, sustainable development of atomic energy will require the development of new types of reactors able to exceed the limits of the existing reactor types, be it in terms of optimum use of natural fuel resources, reduction in the production of long-lived radioactive waste, or economic competitiveness. Of the various candidates with the potential to meet these needs, molten-salt reactors are particularly attractive, in the light of the benefits they offer, arising from two fundamental features: - A liquid fuel does away with the constraints inherent in solid fuel, leading to a drastic simplification of the fuel cycle, in particular making in possible to carry out on-line pyrochemical reprocessing; - Thorium cycle and thermal spectrum breeding. The MSBR concept proposed by ORNL in the 1970's thus gave a breeding factor of 1.06, with a doubling time of about 25 years. However, given the tight neutron balance of the thorium cycle (the η of 233U is about 2.3), MSBR performance is only possible if there are strict constraints set on the in-line reprocessing unit: all the 233Pa must be removed from the core so that it can decay on the 233U in no more than about ten days (or at least 15 tonnes of salt to be extracted from the core daily), and the absorbing fission products, in particular the rare earths, must be extracted in about fifty days. With the AMSTER MSR concept, which we initially developed for incinerating transuranium elements, we looked to reduce the mass of salt to be reprocessed in order to minimise the size and complexity of the reprocessing unit coupled to the reactor, and the quantity of transuranium elements sent for disposal, as this is directly proportional to the mass of salt reprocessed for extraction of the fission products. Given that breeding was not an absolute necessity, because the reactor can be started by incinerating the transuranium elements from the spent fuel assemblies of current reactors, or if necessary by loading

  9. Qualification and initial characterization of a high-purity 233U spike for use in uranium analyses

    International Nuclear Information System (INIS)

    Several high-purity 233U items potentially useful as isotope dilution mass spectrometry standards for safeguards, non-proliferation, and nuclear forensics measurements are identified and rescued from downblending. By preserving the supply of 233U materials of different pedigree for use as source materials for certified reference materials (CRMs), it is ensured that the safeguards community has high quality uranium isotopic standards required for calibration of the analytical instruments. One of the items identified as a source material for a high-purity CRM is characterized for the uranium isotope-amount ratios using thermal ionization mass spectrometry (TIMS). Additional verification measurements on this material using quadrupole inductively coupled plasma mass spectrometry (ICPMS) are also performed. As a result, the comparison of the ICPMS uranium isotope-amount ratios with the TIMS data, with much smaller uncertainties, validated the ICPMS measurement practices. ICPMS is proposed for the initial screening of the purity of items in the rescue campaign

  10. Fractional independent yields of 141La and 142La from thermal-neutron-induced fission of 233U

    International Nuclear Information System (INIS)

    The fractional independent yields of 141La and 142La from thermal-neutron-induced fission of 233U were found to be 0.026 +- 0.006 and 0.068 +- 0.010, respectively. These yields are consistent with charge distributions for which σ = 0.56 +- 0.02 and 0.52 +- 0.02, respectively. These results are in good agreement with similar yields measured for fission of 235U, but not with those from fission of 249Cf. (author)

  11. Investigation of the fission yields of the fast neutron-induced fission of {sup 233}U; Mesure de la distribution en masse et en charge des produits de la fission rapide de l'{sup 233}U

    Energy Technology Data Exchange (ETDEWEB)

    Galy, J

    1999-09-01

    As a stars, a survey of the different methods of investigations of the fission product yields and the experimental data status have been studied, showing advantages and shortcomings for the different approaches. An overview of the existing models for the fission product distributions has been as well intended. The main part of this thesis was the measurement of the independent yields of the fast neutron-induced fission of{sup 233}U, never investigated before this work. The experiment has been carried out using the mass separator OSIRIS (Isotope Separator On-Line). Its integrated ion-source and its specific properties required an analysis of the delay-parameter and ionisation efficiency for each chemical species. On the other hand, this technique allows measurement of independent yields and cumulative yields for elements from Cu to Ba, covering most of the fission yield distribution. Thus, we measured about 180 independent yields from Zn (Z=30) to Sr (Z=38) in the mass range A=74-99 and from Pd (Z=46) to Ba (Z=56) in the mass range A=113-147, including many isomeric states. An additional experiment using direct {gamma}-spectroscopy of aggregates of fission products was used to determine more than 50 cumulative yields of element with half-life from 15 min to a several days. All experimental data have been compared to estimates from a semi-empirical model, to calculated values and to evaluated values from the European library JEF 2.2. Furthermore, a study of both thermal and fast neutron-induced fission of {sup 233}U measured at Studsvik, the comparison of the OSIRIS and LOHENGRIN facilities and the trends in new data for the Reactors Physics have been discussed. (author)

  12. Multiplicity and energy of neutrons from {sup 233}U(n{sub th},f) fission fragments

    Energy Technology Data Exchange (ETDEWEB)

    Nishio, Katsuhisa; Kimura, Itsuro; Nakagome, Yoshihiro [Kyoto Univ. (Japan)

    1998-03-01

    The correlation between fission fragments and prompt neutrons from the reaction {sup 233}U(n{sub th},f) was measured with improved accuracy. The results determined the neutron multiplicity and emission energy as a function of fragment mass and total kinetic energy. The average energy as a function of fragment mass followed a nearly symmetric distribution centered about the equal mass-split and formed a remarkable contrast with the saw-tooth distribution of the average neutron multiplicity. The neutron multiplicity from the specified fragment decreases linearly with total kinetic energy, and the slope of multiplicity with kinetic energy had the minimum value at about 130 u. The level density parameter versus mass determined from the neutron data showed a saw-tooth structure with the pronounced minimum at about 128 and generally followed the formula by Gilbert and Cameron, suggesting that the neutron emission process was very much affected by the shell-effect of the fission fragment. (author)

  13. Cost-based optimizations of power density and target-blanket modularity for {sup 232}Th/{sup 233}U-based ADEP

    Energy Technology Data Exchange (ETDEWEB)

    Krakowski, R.A.

    1995-07-01

    A cost-based parametric systems model is developed for an Accelerator-Driven Energy Production (ADEP) system based on a {sup 232}Th/{sup 233}U fuel cycle and a molten-salt (LiF/BeF{sub 2}/ThF{sub 3}) fluid-fuel primary system. Simplified neutron-balance, accelerator, reactor-core, chemical-processing, and balance-of-plant models are combined parametrically with a simplified costing model. The main focus of this model is to examine trade offs related to fission power density, reactor-core modularity, {sup 233}U breeding rate, and fission product transmutation capacity.

  14. Utilization of non-weapons-grade plutonium and highly enriched uranium with breeding of the 233U isotope in the VVER reactors using thorium and heavy water

    Science.gov (United States)

    Marshalkin, V. E.; Povyshev, V. M.

    2015-12-01

    A method for joint utilization of non-weapons-grade plutonium and highly enriched uranium in the thorium-uranium—plutonium oxide fuel of a water-moderated reactor with a varying water composition (D2O, H2O) is proposed. The method is characterized by efficient breeding of the 233U isotope and safe reactor operation and is comparatively simple to implement.

  15. Utilization of non-weapons-grade plutonium and highly enriched uranium with breeding of the 233U isotope in the VVER reactors using thorium and heavy water

    International Nuclear Information System (INIS)

    A method for joint utilization of non-weapons-grade plutonium and highly enriched uranium in the thorium–uranium—plutonium oxide fuel of a water-moderated reactor with a varying water composition (D2O, H2O) is proposed. The method is characterized by efficient breeding of the 233U isotope and safe reactor operation and is comparatively simple to implement

  16. Dissolution of unirradiated UO{sub 2} and UO{sub 2} doped with {sup 233}U under reducing conditions

    Energy Technology Data Exchange (ETDEWEB)

    Ollila, K. [VTT Processes (Finland); Oversby, V.M. [VMO Konsult (Sweden)

    2005-01-01

    Experiments have been conducted to determine an upper limit to the dissolution rate of UO{sub 2} under reducing conditions appropriate to those in a geologic repository for spent fuel disposal in Finland and Sweden. Test duration ranged from 52 to 140 days. The total amount of U recovered in each test was converted into a dissolution rate per year for the sample. The dissolution rate was then used to calculate an expected lifetime for the samples under the test conditions. The dissolution rate did not depend on the length of the testing period. Rather, the dissolution rate appeared to decrease as the samples were exposed to sequential testing periods. This indicates that the results are still influenced by transient effects such as high-energy surface sites, which implies that the dissolution rates measured are upper limits. The sample lifetimes calculated from the last two testing periods, which had a total of 269 days, ranged from 7 to 10 million years. There was no indication of an effect of alpha radiolysis on the dissolution rate results for samples with doping levels of 0, 5, and 10% {sup 233}U.

  17. Measurement of the $^{233}$U neutron capture cross section at the n_TOF facility at CERN

    CERN Document Server

    Carrapiço, Carlos; Berthoumieux, Eric; Gonçalves, Isabel; Gunsing, Frank

    2012-12-12

    The Thorium-Uranium (Th-U) fuel cycle has been envisaged as an alternative to the Uranium-Plutonium (U-Pu) fuel cycle for electricity generation using nuclear power reactors. Indeed, thorium can be used as a nuclear fuel, and several studies and R&D programs seem to provide evidence on the sustainability of the Th-U fuel cycle, due to (i) the natural abundance of Thorium, (ii) the improved proliferation resistance offered by the Th-U fuel cycle relative to the U-Pu fuel cycle, (iii) the better neutronics performance of the Th-U fuel cycle throughout the whole neutron energy range compared to the U-Pu fuel cycle, (iv) the lower radiotoxicity of the generated spent fuel in reactors with Th-U fuel cycle and, consequently (v) better economics and public acceptance of the reactors operated using the Th-U fuel cycle compared to those using the U-Pu fuel cycle (prior to the Generation IV nuclear reactors). In a nuclear reactor operated using the Th-U fuel cycle, $^{233}$U is a key nuclide governing the neutr...

  18. Evaluation of the thermal-neutron constants for 233U, 235U, 239Pu and 241Pu

    International Nuclear Information System (INIS)

    A consistent set of best values of the 2200 meter/second neutron cross sections, Westcott g-factors, and fission neutron yields for 233U, 235U, 239Pu and 241Pu are presented. A least squares fitting program, LSF, is used to obtain the best fit and to estimate the sensitivity of these fissile parameters to the quoted uncertainties in experimental data. The half-lives of the uranium and plutonium nuclides have been evaluated and these have been used to reassess the significant experimental data. The latest revision of the spontaneous fission neutron yield anti nu, of 252Cf and the foil thickness corrections to the fission neutron yield ratios of fissile nuclei to 252Cf are included. These lead to greater consistency in the data used for anti nu (252Cf). Similarly, the 234U half-life as revised leads to improved consistency in the 235U fission cross section. Comparison is made with the values from ENDF/B-V and other evaluations

  19. Neutron-induced fission cross-section of {sup 233}U in the energy range 0.5

    Energy Technology Data Exchange (ETDEWEB)

    Belloni, F.; Milazzo, P.M.; Abbondanno, U.; Fujii, K.; Moreau, C. [Istituto Nazionale di Fisica Nucleare (INFN), Trieste (Italy); Calviani, M. [Laboratori Nazionali di Legnaro, Istituto Nazionale di Fisica Nucleare (INFN), Legnaro (Italy); CERN, Geneva (Switzerland); Colonna, N.; Marrone, S.; Meaze, M.H.; Tagliente, G.; Terlizzi, R. [Istituto Nazionale di Fisica Nucleare (INFN), Bari (Italy); Mastinu, P.; Gramegna, F. [Laboratori Nazionali di Legnaro, Istituto Nazionale di Fisica Nucleare, Legnaro (Italy); Aerts, G.; Andriamonje, S.; Berthoumieux, E.; Dridi, W.; Gunsing, F.; Pancin, J.; Perrot, L.; Plukis, A. [CEA, Irfu, Gif-sur-Yvette (France); Alvarez, H.; Cano-Ott, D.; Duran, I.; Embid-Segura, M.; Gonzalez-Romero, E.; Paradela, C. [Univ. de Santiago de Compostela, Santiago (Spain); Alvarez-Velarde, F.; Guerrero, C.; Martinez, T.; Villamarin, D.; Vincente, M.C. [Centro de Investigaciones Energeticas Medioambientales y Technologicas, Madrid (Spain); Andrzejewski, J.; Marganiec, J. [Univ. of Lodz, Lodz (Poland); Audouin, L.; Dillmann, I.; Heil, M.; Kaeppeler, F.; Mosconi, M.; Plag, R.; Voss, F.; Walter, S.; Wisshak, K. [Inst. fuer Kernphysik, Karlsruhe Inst. of Technology, Campus Nord, Karlsruhe (Germany); Badurek, G.; Jericha, E.; Leeb, H.; Oberhummer, H.; Pigni, M.T. [Technische Univ. Wien, Atominstitut der Oesterreichischen Univ., Wien (Austria); Baumann, P.; David, S.; Kerveno, M.; Lukic, S.; Rudolf, G. [Centre National de la Recherche Scientifique/IN2P3 - IReS, Strasbourg (France); Becvar, F.; Krticka, M. [Charles Univ., Faculty of Mathematics and Physics, Prague (Czech Republic); Calvino, F.; Cortes, G.; Poch, A.; Pretel, C. [Univ. Politecnica de Catalunya, Barcelona (Spain); Capote, R. [NAPC/Nuclear Data Section, International Atomic Energy Agency, Vienna (Austria); Univ. de Sevilla, Sevilla (Spain); Carrapico, C.; Goncalves, I.; Salgado, J.; Santos, C.; Tavora, L.; Vaz, P. [Inst. Tecnologico e Nuclear, Lisbon (Portugal)] [and others

    2011-01-15

    The neutron-induced fission cross-section of {sup 233}U has been measured at the CERN n-TOF facility relative to the standard fission cross-section of {sup 235}U between 0.5 and 20MeV. The experiment was performed with a fast ionization chamber for the detection of the fission fragments and to discriminate against {alpha} -particles from the natural radioactivity of the samples. The high instantaneous flux and the low background of the n-TOF facility result in data with uncertainties of {approx} 3%, which were found in good agreement with previous experiments. The high quality of the present results allows to improve the evaluation of the {sup 233}U (n,f) cross-section and, consequently, the design of energy systems based on the Th/U cycle. (orig.)

  20. Delayed Fission Gamma-ray Characteristics of Th-232 U-233 U-235 U-238 and Pu-239

    Energy Technology Data Exchange (ETDEWEB)

    Lane, Taylor [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Parma, Edward J. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)

    2015-08-01

    Delayed fission gamma-rays play an important role in determining the time dependent ioniz- ing dose for experiments in the central irradiation cavity of the Annular Core Research Reactor (ACRR). Delayed gamma-rays are produced from both fission product decay and from acti- vation of materials in the core, such as cladding and support structures. Knowing both the delayed gamma-ray emission rate and the time-dependent gamma-ray energy spectrum is nec- essary in order to properly determine the dose contributions from delayed fission gamma-rays. This information is especially important when attempting to deconvolute the time-dependent neutron, prompt gamma-ray, and delayed gamma-ray contribution to the response of a diamond photo-conducting diode (PCD) or fission chamber in time frames of milliseconds to seconds following a reactor pulse. This work focused on investigating delayed gamma-ray character- istics produced from fission products from thermal, fast, and high energy fission of Th-232, U-233, U-235, U-238, and Pu-239. This work uses a modified version of CINDER2008, a transmutation code developed at Los Alamos National Laboratory, to model time and energy dependent photon characteristics due to fission. This modified code adds the capability to track photon-induced transmutations, photo-fission, and the subsequent radiation caused by fission products due to photo-fission. The data is compared against previous work done with SNL- modified CINDER2008 [ 1 ] and experimental data [ 2 , 3 ] and other published literature, includ- ing ENDF/B-VII.1 [ 4 ]. The ability to produce a high-fidelity (7,428 group) energy-dependent photon fluence at various times post-fission can improve the delayed photon characterization for radiation effects tests at research reactors, as well as other applications.

  1. Utilization of non-weapons-grade plutonium and highly enriched uranium with breeding of the {sup 233}U isotope in the VVER reactors using thorium and heavy water

    Energy Technology Data Exchange (ETDEWEB)

    Marshalkin, V. E., E-mail: marshalkin@vniief.ru; Povyshev, V. M. [Russian Federal Nuclear Center All-Russian Research Institute of Experimental Physics (Russian Federation)

    2015-12-15

    A method for joint utilization of non-weapons-grade plutonium and highly enriched uranium in the thorium–uranium—plutonium oxide fuel of a water-moderated reactor with a varying water composition (D{sub 2}O, H{sub 2}O) is proposed. The method is characterized by efficient breeding of the {sup 233}U isotope and safe reactor operation and is comparatively simple to implement.

  2. Measurement of neutron induced fission of {sup 235}U, {sup 233}U and {sup 245}Cm with the FIC detector at the CERN n-TOF facility

    Energy Technology Data Exchange (ETDEWEB)

    Calviani, M.; Karadimos, D.; Abbondanno, U.; Aerts, G.; Alvarez, H.; Alvarez-Velarde, F.; Andriamonje, S.; Andrzejewski, J.; Assimakopoulos, P.; Audouin, L.; Badurek, G.; Baumann, P.; Becvar, F.; Berthoumieux, E.; Calvino, F.; Cano-Ott, D.; Capote, R.; Carrapic, C.; Cennini, P.; Chepel, V.; Chiaveri, E.; Colonna, N.; Cortes, G.; Couture, A.; Cox, J.; Dahlfors, M.; David, S.; Dillmann, I.; Domingo-Pardo, C.; Dridi, W.; Duran, I.; Eleftheriadis, C.; Embid-Segura, M.; Ferrant, L.; Ferrari, A.; Ferreira-Marques, R.; Fujii, K.; Furman, W.; Goncalves, I.; Gonzalez-Romero, E.; Gramegna, F.; Guerrero, C.; Gunsing, F.; Haas, B.; Haight, R.; Heil, M.; Herrera-Martinez, A.; Igashira, M.; Jericha, E.; Kappeler, F.; Kadi, Y.; Karamanis, D.; Kerveno, M.; Koehler, P.; Kossionides, E.; Krticka, M.; Lampoudis, C.; Leeb, H.; Lindote, A.; Lopes, I.; Lozano, M.; Lukic, S.; Marganiec, J.; Marrone, S.; Martinez, T.; Massimi, C.; Mastinu, P.; Mengoni, A.; Milazzo, P.M.; Moreau, C.; Mosconi, M.; Neves, F.; Oberhummer, H.; O' Brien, S.; Pancin, J.; Papachristodoulou, C.; Papadopoulos, C.; Paradela, C.; Patronis, N.; Pavlik, A.; Pavlopoulos, P.; Perrot, L.; Pigni, M.T.; Plag, R.; Plompen, A.; Plukis, A.; Poch, A.; Praena, J.; Pretel, C.; Quesada, J.; Rauscher, T.; Reifarth, R.; Rubbia, C.; Rudolf, G.; Rullhusen, P.; Salgado, J.; Santos, C.; Sarchiapone, L.; Savvidis, I.; Stephan, C.; Tagliente, G.; Tain, J.L.; Tassan-Got, L.; Tavora, L.; Terlizzi, R.; Vannini, G.; Vaz, P.; Ventura, A.; Villamarin, D.; Vincente, M.C.; Vlachoudis, V.; Vlastou, R.; Voss, F.; Walter, S.; Wiescher, M.; Wisshak, K

    2008-07-01

    A series of measurements of neutron induced fission cross section of various transuranic isotopes have been performed at the CERN n-TOF spallation neutron facility, in the energy range from thermal to nearly 250 MeV. The experimental apparatus consists in a fast ionization chamber (FIC), used as a fission fragment detector with a high efficiency. Good discrimination between alphas and fission fragments can be obtained with a simple amplitude threshold. In order to allow the monitoring of the neutron beam and to extract the n-TOF neutron flux, the well known cross section of the {sup 235}U(n,f) reaction, considered as a fission standard, has been used. Preliminary results for the cross section are shown for some selected isotopes such as {sup 235}U, {sup 233}U and {sup 245}Cm in the energy range from 0.050 eV to about 2 MeV. These results for {sup 235}U, {sup 233}U and {sup 245}Cm show results consistent with databases in the resonance region, with no normalization required for {sup 233}U. In the case of {sup 245}Cm, for the energy range between thermal and 20 eV, we obtained the first experimental data ever published, while showing a good agreement with previous data in the region above that value.

  3. Evaluation of fission cross sections and covariances for {sup 233}U, {sup 235}U, {sup 238}U, {sup 239}Pu, {sup 240}Pu, and {sup 241}Pu

    Energy Technology Data Exchange (ETDEWEB)

    Kawano, Toshihiko [Kyushu Univ., Fukuoka (Japan); Matsunobu, Hiroyuki [Data Engineering, Inc. (Japan); Murata, Toru [AITEL Corporation, Tokyo (JP)] [and others

    2000-02-01

    A simultaneous evaluation code SOK (Simultaneous evaluation on KALMAN) has been developed, which is a least-squares fitting program to absolute and relative measurements. The SOK code was employed to evaluate the fission cross sections of {sup 233}U, {sup 235}U, {sup 238}U, {sup 239}Pu, {sup 240}Pu, and {sup 241}Pu for the evaluated nuclear data library JENDL-3.3. Procedures of the simultaneous evaluation and the experimental database of the fission cross sections are described. The fission cross sections obtained were compared with evaluated values given in JENDL-3.2 and ENDF/B-VI. (author)

  4. Neutron-induced fission cross sections of 233U and 243Am in the energy range 0.5 Mev En 20 MeV @ n_TOF

    CERN Document Server

    Belloni, F; Milazzo, P M; Calviani, M; Colonna, N; Mastinu, P; Abbondanno, U; Aerts, G; Álvarez, H; Álvarez-Velarde, F; Andriamonje, S; Andrzejewski, J; Assimakopoulos, P; Audouin, L; Badurek, G; Baumann, P; Becvár, F; Berthoumieux, E; Calviño, F; Cano-Ott, D; Capote, R; Carrapiço, C; Cennini, P; Chepel, V; Chiaveri, E; Cortes, G; Couture, A; Cox, J; Dahlfors, M; David, S; Dillmann, I; Domingo-Pardo, C; Dridi, W; Duran, I; Eleftheriadis, C; Embid-Segura, M; Ferrant, L; Ferrari, A; Ferreira-Marques, R; Fujii, K; Furman, W; Goncalves, I; González-Romero, E; Gramegna, F; Guerrero, C; Gunsing, F; Haas, B; Haight, R; Heil, M; Herrera-Martinez, A; Igashira, M; Jericha, E; Käppeler, F; Kadi, Y; Karadimos, D; Karamanis, D; Kerveno, M; Koehler, P; Kossionides, E; Krticka, M; Lampoudis, C; Leeb, H; Lindote, A; Lopes, I; Lozano, M; Lukic, S; Marganiec, J; Marrone, S; Martínez, T; Massimi, C; Mengoni, A; Moreau, C; Mosconi, M; Neves, F; Oberhummer, H; O'Brien, S; Pancin, J; Papachristodoulou, C; Papadopoulos, C; Paradela, C; Patronis, N; Pavlik, A; Pavlopoulos, P; Perrot, L; Pigni, M T; Plag, R; Plompen, A; Plukis, A; Poch, A; Praena, J; Pretel, C; Quesada, J; Rauscher, T; Reifarth, R; Rubbia, C; Rudolf, G; Rullhusen, P; Salgado, J; Santos, C; Sarchiapone, L; Savvidis, I; Stephan, C; Tagliente, G; Tain, J L; Tassan-Got, L; Tavora, L; Terlizzi, R; Vannini, G; Vazl, P; Ventura, A; Villamarin, D; Vincente, M C; Vlachoudis, V; Vlastou, R; Voss, F; Walter, S; Wiescher, M; Wisshak, K

    2011-01-01

    Neutron-induced fission cross-sections of actinides have been recently measured at the neutron time of flight facility n_TOF at CERN in the frame of a research project involving isotopes relevant for nuclear astrophysics and nuclear technologies. Fission fragments are detected by a gas counter with good discrimination between nuclear fission products and background events. Neutron-induced fission cross-sections of 233U and 243Am were determined relative to 235U. The present paper reports the results obtained at neutron energies between 0.5 and 20 MeV.

  5. Determination of the extraction efficiency for $^{233}$U source $\\alpha$-recoil ions from the MLL buffer-gas stopping cell

    CERN Document Server

    von der Wense, Lars; Laatiaoui, Mustapha; Thirolf, Peter G

    2016-01-01

    Following the $\\alpha$ decay of $^{233}$U, $^{229}$Th recoil ions are shown to be extracted in a significant amount from the MLL buffer-gas stopping cell. The produced recoil ions and subsequent daughter nuclei are mass purified with the help of a customized quadrupole mass spectrometer. The combined extraction and mass-purification efficiency for $^{229}$Th$^{3+}$ is determined via MCP-based measurements and via the direct detection of the $^{229}$Th $\\alpha$ decay. A large value of $(10\\pm2)$\\% for the combined extraction and mass-purification efficiency of $^{229}$Th$^{3+}$ is obtained at a mass resolution of about 1 u/e. In addition to $^{229}$Th, also other $\\alpha$-recoil ions of the $^{233,232}$U decay chains are addressed.

  6. R-MATRIX RESONANCE ANALYSIS AND STATISTICAL PROPERTIES OF THE RESONANCE PARAMETERS OF 233U IN THE NEUTRON ENERGY RANGE FROM THERMAL TO 600 eV

    Energy Technology Data Exchange (ETDEWEB)

    Leal, L.C.

    2001-02-27

    The R-matrix resonance analysis of experimental neutron transmission and cross sections of {sup 233}U, with the Reich-Moore Bayesian code SAMMY, was extended up to the neutron energy of 600 eV by taking advantage of new high resolution neutron transmission and fission cross section measurements performed at the Oak Ridge Electron Linear Accelerator (ORELA). The experimental data base is described. In addition to the microscopic data (time-of-flight measurements of transmission and cross sections), some experimental and evaluated integral quantities were included in the data base. Tabulated and graphical comparisons between the experimental data and the SAMMY calculated cross sections are given. The ability of the calculated cross sections to reproduce the effective multiplication factors k{sub eff} for various thermal, intermediate, and fast systems was tested. The statistical properties of the resonance parameters were examined and recommended values of the average s-wave resonance parameters are given.

  7. Measurement of the generation ratio of 233U and the average radiation capture cross section of 232Th with 232ThO2 irradiated by fast neutrons

    International Nuclear Information System (INIS)

    Background: Thorium-Uranium cycle plays an important role in the future's power production technology. Nuclear data involved are urgently needed for engineering design and other purposes since there are obvious differences between the existing evaluated data. Macroscopic neutron integral experiment can be used as a good tool to survey the confusion. Purpose: Macroscopic neutron integral experiment based on radioactive method was carried out to measure the generation ratio of 233U nuclide and the average radiation capture cross section of 232Th while a ThO2 sample was irradiated by fast neutrons leakage from a fast critical facility. We expect that these data can be used as a reference for the research of Th-U cycle. Methods: Radiation capture reactions of 232Th nuclides occur when the nuclides are irradiated by neutrons. 233U nuclides will be generated after two cascade decays by emitting beta rays from the activation products, which are 233Th nuclides. The ThO2 sample was prepared as a slice of 20 mm×10 mm from 0.743 36-g ThO2 powders of 99.9% enriched. The neutron flux was measured by activation method which was 4.07x109 cm-2·s-1 at the sample's irradiation position while the facility worked at the power level of 180 watts. The leakage neutrons' energy distribution was calculated by MC method and it is very close to the fission spectrum with the averaged energy of 1.42 MeV. After irradiation and then a period of cooling time the gamma rays emitted from the sample were measured by an HPGe spectrometer which had been pre-calibrated. From these data the activity of 233Pa was calculated and then the generation ratio of 233U and the average radiation capture cross section of 232Th were calculated. The measured average radiation capture cross section was compared with the cross sections calculated based on the ENDFB-VH.1, CENDL-3.1, JENDL-4.0, BROND2.2 databases. Results: The measured generation ratio of 233U was 4.01×10-12 with an uncertainty of 6

  8. Fission Cross-section Measurements of (233)U, (245)Cm and (241,243)Am at CERN n_TOF Facility

    CERN Document Server

    Calviani, M; Andriamonje, S; Chiaveri, E; Vlachoudis, V; Colonna, N; Meaze, M H; Marrone, S; Tagliente, G; Terlizzi, R; Belloni, F; Abbondanno, U; Fujii, K; Milazzo, P M; Moreau, C; Aerts, G; Berthoumieux, E; Dridi, W; Gunsing, F; Pancin, J; Perrot, L; Plukis, A; Alvarez, H; Duran, I; Paradela, C; Alvarez-Velarde, F; Cano-Ott, D; Gonzalez-Romero, E; Guerrero, C; Martinez, T; Villamarin, D; Vicente, M C; Andrzejewski, J; Marganiec, J; Assimakopoulos, P; Karadimos, D; Karamanis, D; Papachristodoulou, C; Patronis, N; Audouin, L; David, S; Ferrant, L; Isaev, S; Stephan, C; Tassan-Got, L; Badurek, G; Jericha, E; Leeb, H; Oberhummer, H; Pigni, M T; Baumann, P; Kerveno, M; Lukic, S; Rudolf, G; Becvar, F; Krticka, M; Calvino, F; Capote, R; Carrillo De Albornoz, A; Marques, L; Salgado, J; Tavora, L; Vaz, P; Cennini, P; Dahlfors, M; Ferrari, A; Gramegna, F; Herrera-Martinez, A; Kadi, Y; Mastinu, P; Praena, J; Sarchiapone, L; Wendler, H; Chepel, V; Ferreira-Marques, R; Goncalves, I; Lindote, A; Lopes, I; Neves, F; Cortes, G; Poch, A; Pretel, C; Couture, A; Cox, J; O'brien, S; Wiescher, M; Dillman, I; Heil, M; Kappeler, F; Mosconi, M; Plag, R; Voss, F; Walter, S; Wisshak, K; Dolfini, R; Rubbia, C; Domingo-Pardo, C; Tain, J L; Eleftheriadis, C; Savvidis, I; Frais-Koelbl, H; Griesmayer, E; Furman, W; Konovalov, V; Goverdovski, A; Ketlerov, V; Haas, B; Haight, R; Reifarth, R; Igashira, M; Koehler, P; Kossionides, E; Lampoudis, C; Lozano, M; Quesada, J; Massimi, C; Vannini, G; Mengoni, A; Oshima, M; Papadopoulos, C; Vlastou, R; Pavlik, A; Pavlopoulos, P; Plompen, A; Rullhusen, P; Rauscher, T; Rosetti, M; Ventura, A

    2011-01-01

    Neutron-induced fission cross-sections of minor actinides have been measured using the n_TOF white neutron source at CERN, Geneva, as part of a large experimental program aiming at collecting new data relevant for nuclear astrophysics and for the design of advanced reactor systems. The measurements at n_TOF take advantage of the innovative features of the n_TOF facility, namely the wide energy range, high instantaneous neutron flux and good energy resolution. Final results on the fission cross-section of 233U, 245Cm and 243Am from thermal to 20 MeV are here reported, together with preliminary results for 241Am. The measurement have been performed with a dedicated Fast Ionization Chamber (FIC), a fission fragment detector with a very high efficiency, relative to the very well known cross-section of 235U, measured simultaneously with the same detector.

  9. Fusion hybrids for generation of advanced (231Pa+232U+233U+234U)-fuel in closed (U-Pu-Th)-fuel cycle

    International Nuclear Information System (INIS)

    Technology of controlled thermonuclear fusion (CTF) is traditionally regarded as a practically inexhaustible energy source. However, development, mastering, broad deployment of fast breeder reactors and closure of nuclear fuel cycle (NFC) can also extend fuel base of nuclear power industry (NPI) up to practically unlimited scales. Under these conditions, it seems reasonable to introduce into a circle of the CTF-related studies the works directed towards solving some principal problems which can appear in a large-scale NPI in closed NFC. The first challenge is a large scale of operations in NFC back-end that should be reduced by achieving substantially higher fuel burn-up in power nuclear reactors. The use of 231Pa-232Th-232U-233U fuel in light-water reactor (LWR) opens a possibility of principle to reach very high (about 30% HM) or even ultra-high fuel burn-up. The second challenge is a potential unauthorized proliferation of fissionable materials. As is known, a certain remarkable quantity of 232U being introduced into uranium fraction of nuclear fuel can produce a serious barrier against switching the fuel over to non-energy purposes. Involvement of hybrid thermonuclear reactors (HTR) into NPI structure can substantially facilitate resolving these problems. If HTR will be involved into NPI structure, then main HTR mission consists not in energy generation but in production of nuclear fuel with a certain isotope composition. The present paper analyzes some neutron-physical features in production of advanced nuclear fuels in thorium HTR blankets. The obtained results demonstrated that such a nuclear fuel may be characterized by very stable neutron-multiplying properties during full LWR operation cycle and by enhanced proliferation resistance too. The paper evaluates potential benefits from involvement of HTR with thorium blanket into the international closed NFC. (author)

  10. Expeditious method to determine uranium in the process control samples of chemical plant separating (233)U from thoria irradiated in power reactors.

    Science.gov (United States)

    Kedari, C S; Kharwandikar, B K; Banerjee, K

    2016-11-01

    Analysis of U in the samples containing a significant proportion of (232)U and high concentration of Th is of great concern. Transmutation of Th in the nuclear power reactor produces a notable quantity of (232)U (half life 68.9 years) along with fissile isotope (233)U. The decay series of (232)U is initiated with (228)Th (half life 1.9 year) and it is followed by several short lived α emitting progenies, (224)Ra, (220)Rn, (216)Po, (212)Bi and (212)Po. Even at the smallest contamination of (228)Th in the sample, a very high pulse rate of α emission is obtained, which is to be counted for the radiometric determination of [U]. A commercially available anionic type of extractant Alamine®336 is used to obtain the selective extraction of U from other alpha active elements and fission products present in the sample. Experimental conditions of liquid-liquid extraction (LLE) are optimized for obtaining maximum decontamination and recovery of U in the organic phase. The effect of some interfering ionic impurities in the sample on the process of separation is investigated. Depending on the level of the concentration of U in the samples, spectrophotometry or radiometry methods are adopted for its determination after separation by LLE. Under optimized experimental conditions, i.e. 5.5M HCl in the aqueous phase and 0.27M Alamin®336 in the organic phase, the recovery of U is about 100%, the decontamination factor with respect to Th is >2000 and the extraction of fission products like (90)Sr, (144)Ce and (134,137)Cs is negligible. The detection limit for [U] using α radiometry is 10mg/L, even in presence of >100g/L of Th in the sample. Accuracy and precision for the determination of U is also assessed. Reproducibility of results is within 5%. This method shows very good agreement with the results obtained by mass spectrometry.

  11. The effect of dissolved hydrogen on the dissolution of {sup 233}U doped UO{sub 2}(s) high burn-up spent fuel and MOX fuel

    Energy Technology Data Exchange (ETDEWEB)

    Carbol, P. [Inst. for Transuranium Elements, Karlsruhe (Germany); Spahiu, K. (ed.) [and others

    2005-03-01

    In this report the results of the experimental work carried out in a large EU-research project (SFS, 2001-2004) on spent fuel stability in the presence of various amounts of near field hydrogen are presented. Studies of the dissolution of {sup 233}U doped UO{sub 2}(s) simulating 'old' spent fuel were carried out as static leaching tests, autoclave tests with various hydrogen concentrations and electrochemical tests. The results of the leaching behaviour of a high burn-up spent fuel pellet in 5 M NaCl solutions in the presence of 3.2 bar H{sub 2} pressure and of MOX fuel in dilute synthetic groundwater under 53 bar H{sub 2} pressure are also presented. In all the experimental studies carried out in this project, a considerable effect of hydrogen in the dissolution rates of radioactive materials was observed. The experimental results obtained in this project with a-doped UO{sub 2}, high burn-up spent fuel and MOX fuel together with literature data give a reliable background to use fractional alteration/dissolution rates for spent fuel of the order of 10{sup -6}/yr - 10{sup -8}/yr with a recommended value of 4x10{sup -7}/yr for dissolved hydrogen concentrations above 10{sup -3} M and Fe(II) concentrations typical for European repository concepts. Finally, based on a review of the experimental data and available literature data, potential mechanisms of the hydrogen effect are also discussed. The work reported in this document was performed as part of the Project SFS of the European Commission 5th Framework Programme under contract no FIKW-CT-2001-20192 SFS. It represents the deliverable D10 of the experimental work package 'Key experiments using a-doped UO{sub 2} and real spent fuel', coordinated by SKB with the participation of ITU, FZK-INE, ENRESA, CIEMAT, ARMINES-SUBATECH and SKB.

  12. Expeditious method to determine uranium in the process control samples of chemical plant separating (233)U from thoria irradiated in power reactors.

    Science.gov (United States)

    Kedari, C S; Kharwandikar, B K; Banerjee, K

    2016-11-01

    Analysis of U in the samples containing a significant proportion of (232)U and high concentration of Th is of great concern. Transmutation of Th in the nuclear power reactor produces a notable quantity of (232)U (half life 68.9 years) along with fissile isotope (233)U. The decay series of (232)U is initiated with (228)Th (half life 1.9 year) and it is followed by several short lived α emitting progenies, (224)Ra, (220)Rn, (216)Po, (212)Bi and (212)Po. Even at the smallest contamination of (228)Th in the sample, a very high pulse rate of α emission is obtained, which is to be counted for the radiometric determination of [U]. A commercially available anionic type of extractant Alamine®336 is used to obtain the selective extraction of U from other alpha active elements and fission products present in the sample. Experimental conditions of liquid-liquid extraction (LLE) are optimized for obtaining maximum decontamination and recovery of U in the organic phase. The effect of some interfering ionic impurities in the sample on the process of separation is investigated. Depending on the level of the concentration of U in the samples, spectrophotometry or radiometry methods are adopted for its determination after separation by LLE. Under optimized experimental conditions, i.e. 5.5M HCl in the aqueous phase and 0.27M Alamin®336 in the organic phase, the recovery of U is about 100%, the decontamination factor with respect to Th is >2000 and the extraction of fission products like (90)Sr, (144)Ce and (134,137)Cs is negligible. The detection limit for [U] using α radiometry is 10mg/L, even in presence of >100g/L of Th in the sample. Accuracy and precision for the determination of U is also assessed. Reproducibility of results is within 5%. This method shows very good agreement with the results obtained by mass spectrometry. PMID:27591623

  13. Preliminary results of calculations for heavy-water nuclear-power-plant reactors employing 235U, 233U, and 232Th as a fuel and meeting requirements of a nonproliferation of nuclear weapons

    Science.gov (United States)

    Ioffe, B. L.; Kochurov, B. P.

    2012-02-01

    A physical design is developed for a gas-cooled heavy-water nuclear reactor intended for a project of a nuclear power plant. As a fuel, the reactor would employ thorium with a small admixture of enriched uranium that contains not more than 20% of 235U. It operates in the open-cycle mode involving 233U production from thorium and its subsequent burnup. The reactor meets the conditions of a nonproliferation of nuclear weapons: the content of fissionable isotopes in uranium at all stages of the process, including the final one, is below the threshold for constructing an atomic bomb, the amount of product plutonium being extremely small.

  14. Measurement of the Neutron Capture Cross Sections of $^{233}$U, $^{237}$Np, $^{240,242}$Pu, $^{241,243}$Am and $^{245}$Cm with a Total Absorption Calorimeter at n_TOF

    CERN Multimedia

    Beer, H; Wiescher, M; Cox, J; Rapp, W; Embid, M; Dababneh, S

    2002-01-01

    Accurate and reliable neutron capture cross section data for actinides are necessary for the poper design, safety regulation and precise performance assessment of transmutation devices such as Fast Critical Reactors or Accelerator Driven Systems (ADS). The goal of this proposal is the measurement of the neutron capture cross sections of $^{233}$U, $^{237}$Np, $^{240,242}$Pu, $^{241,243}$Am and $^{245}$Cm at n_TOF with an accuracy of 5~\\%. $^{233}$U plays an essential role in the Th fuel cycle, which has been proposed as a safer and cleaner alternative to the U fuel cycle. The capture cross sections of $^{237}$Np,$^{240,242}$Pu, $^{241,243}$Am and $^{245}$Cm play a key role in the design and optimization of a strategy for the Nuclear Waste Transmutation. A high accuracy can be achieved at n_TOF in such measurements due to a combination of features unique in the world: high instantaneous neutron fluence and excellent energy resolution of the facility, innovative Data Acquisition System based on flash ADCs and t...

  15. Preliminary study of the α ratio measurement, ratio of the neutron capture cross section to the fission one for 233U, on the PEREN platform. Development and study of the experimental setup

    International Nuclear Information System (INIS)

    Producing nuclear energy in order to reduce anthropic CO2 emission and to meet high energy demand, implies three conditions to the nuclear plants of the IV. generation: safety improvements, radioactive waste minimization, and fuel breeding for a sustainable use of the resources. The Thorium fuel cycle used in Molten Salt Reactors seems promising. Many numerical studies based on probabilistic codes are carried out in order to analyse the behaviour of such reactors. Nevertheless, one of the most important parameters is badly known: the alpha ratio of 233U, ratio of the neutron capture cross section to fission one for 233U. This key-parameter is necessary to calculate the breeding ratio and thus, the deployment capacities of those reactors. This Ph-D thesis was intended to prepare a precise measurement of the alpha ratio of 233U between 1 eV and 10 keV. Preliminary measurements have been performed on the experimental platform PEREN. This experimental environment is composed of a lead slowing-down time spectrometer associated with an intense pulsed neutron generator. Capture and fission rates are measured thanks to eight scintillators with their photomultipliers, surrounding a fission chamber. A software analysis sets the coincidence rate between the scintillators. In order to understand perfectly the experimental setup, preliminary tests using a 235U fission chamber have been done. This experiment resulted in a very low signal to background ratio (1 %). The background coming from the scintillators themselves seriously handicapped the measurement. Another series of experiment has been done with scintillators 5 times thinner. Nevertheless, the signal to background ratio should still be increased to measure the capture of 235U. To make sure that the experimental setup has totally been understood, we made many comparisons between experimental results and simulations. Two simulation codes were mainly used: MCNP and GEANT4. We paid special attention to quantify the

  16. Preliminary study of the {alpha} ratio measurement, ratio of the neutron capture cross section to the fission one for {sup 233}U, on the PEREN platform. Development and study of the experimental setup; Etude preliminaire de la mesure du rapport {alpha}, rapport de la section efficace moyenne de capture sur celle de fission de l'{sup 233}U, sur la plateforme PEREN. Developpement et etude du dispositif experimental

    Energy Technology Data Exchange (ETDEWEB)

    Cognet, M.A

    2007-12-15

    Producing nuclear energy in order to reduce anthropic CO{sub 2} emission and to meet high energy demand, implies three conditions to the nuclear plants of the IV. generation: safety improvements, radioactive waste minimization, and fuel breeding for a sustainable use of the resources. The Thorium fuel cycle used in Molten Salt Reactors seems promising. Many numerical studies based on probabilistic codes are carried out in order to analyse the behaviour of such reactors. Nevertheless, one of the most important parameters is badly known: the alpha ratio of {sup 233}U, ratio of the neutron capture cross section to fission one for {sup 233}U. This key-parameter is necessary to calculate the breeding ratio and thus, the deployment capacities of those reactors. This Ph-D thesis was intended to prepare a precise measurement of the alpha ratio of {sup 233}U between 1 eV and 10 keV. Preliminary measurements have been performed on the experimental platform PEREN. This experimental environment is composed of a lead slowing-down time spectrometer associated with an intense pulsed neutron generator. Capture and fission rates are measured thanks to eight scintillators with their photomultipliers, surrounding a fission chamber. A software analysis sets the coincidence rate between the scintillators. In order to understand perfectly the experimental setup, preliminary tests using a {sup 235}U fission chamber have been done. This experiment resulted in a very low signal to background ratio (1 %). The background coming from the scintillators themselves seriously handicapped the measurement. Another series of experiment has been done with scintillators 5 times thinner. Nevertheless, the signal to background ratio should still be increased to measure the capture of {sup 235}U. To make sure that the experimental setup has totally been understood, we made many comparisons between experimental results and simulations. Two simulation codes were mainly used: MCNP and GEANT4. We paid

  17. Calculation of Prompt Fission Neutron from 233U(n, f) Reaction by Multi-Modal Los Alamos Model%Calculation of Prompt Fission Neutron from 233U(n, f) Reaction by Multi-Modal Los Alamos Model

    Institute of Scientific and Technical Information of China (English)

    郑娜; 钟春来; 樊铁栓

    2012-01-01

    An attempt is made to improve the evaluation of the prompt fission neutron emis- sion from 233U(n, f) reaction for incident neutron energies below 6 MeV. The multi-modal fission approach is applied to the improved version of Los Alamos model and the point by point model. The prompt fission neutron spectra and the prompt fission neutron as a function of fragment mass (usually named "sawtooth" data) v(A) are calculated independently for the three most dominant fission modes (standard I, standard II and superlong), and the total spectra and v(A) are syn- thesized. The multi-modal parameters are determined on the basis of experimental data of fission fragment mass distributions. The present calculation results can describe the experimental data very well, and the proposed treatment is thus a useful tool for prompt fission neutron emission prediction.

  18. Concept of a demonstrational hybrid reactor—a tokamak with molten-salt blanket for {sup 233}U fuel production: 1. Concept of a stationary Tokamak as a neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Azizov, E. A.; Gladush, G. G., E-mail: gladush@triniti.ru; Dokuka, V. N.; Khayrutdinov, R. R. [State Research Center of the Russian Federation, Troitsk Institute for Innovation and Fusion Research (Russian Federation)

    2015-12-15

    On the basis of current understanding of physical processes in tokamaks and taking into account engineering constraints, it is shown that a low-cost facility of a moderate size can be designed within the adopted concept. This facility makes it possible to achieve the power density of neutron flux which is of interest, in particular, for solving the problem of {sup 233}U fuel production from thorium. By using a molten-salt blanket, the important task of ensuring the safe operation of such a reactor in the case of possible coolant loss is accomplished. Moreover, in a hybrid reactor with the blanket based on liquid salts, the problem of periodic refueling that is difficult to perform in solid blankets can be solved.

  19. Concept of a demonstrational hybrid reactor—a tokamak with molten-salt blanket for 233U fuel production: 1. Concept of a stationary Tokamak as a neutron source

    Science.gov (United States)

    Azizov, E. A.; Gladush, G. G.; Dokuka, V. N.; Khayrutdinov, R. R.

    2015-12-01

    On the basis of current understanding of physical processes in tokamaks and taking into account engineering constraints, it is shown that a low-cost facility of a moderate size can be designed within the adopted concept. This facility makes it possible to achieve the power density of neutron flux which is of interest, in particular, for solving the problem of 233U fuel production from thorium. By using a molten-salt blanket, the important task of ensuring the safe operation of such a reactor in the case of possible coolant loss is accomplished. Moreover, in a hybrid reactor with the blanket based on liquid salts, the problem of periodic refueling that is difficult to perform in solid blankets can be solved.

  20. Multilevel analysis of the 233U and 235U capture and fission cross-sections and statistical properties of the Kapur-Peierls-type resonance parameters for the S-wave cross-sections of the fissile isotopes

    International Nuclear Information System (INIS)

    At the 1966 Conference on Nuclear Data for Reactors, simultaneous measurements of the capture and fission cross-sections of 233U and 235U were presented. Those measurements have now been analysed with the multilevel formalism developed by Adler and Adler. To obtain consistent sets of resonance parameters the capture and fission data were least-square fitted simultaneously. This analysis was carried out to 60 eV for 233U and to 100 eV for 235U. The main purpose of this analysis was to provide a simple and precise analytical description of the very complex structure of the fission and capture cross-sections of 233U and 235U at low energy. Such an analytical description should be useful to calculate reaction rates in nuclear reactors and to compare experimental data taken with different energy resolutions or at different sample temperatures. For the low-energy resonances of 233U and 235U, the neutron width is always smaller, by at least two orders of magnitude, than the total width. Thus, the total cross-section, for those isotopes, can be approximated as the sum of the absorption cross-section and the potential scattering cross-section. Hence it is possible to compute the total cross-section from the resonance parameters obtained by fitting the fission and capture cross-sections. The total cross-section of 235U computed by this method is compared to the data from a transmission measurement done at Saclay, with the sample at 77 deg. K. The computed total cross-section of 233U is compared with transmission data obtained at Oak Ridge National Laboratory and at the Material Testing Reactor. Such comparisons between data obtained by different experimental techniques illustrate the internal consistency of the low-energy cross-sections of the two main uranium fissile isotopes. The physical interpretation of the resonance parameters is somewhat ambiguous, because such multilevel fits are by no means unique. This is particularly true for 233U since, for this nucleus, the

  1. Macroeconomic regimes

    NARCIS (Netherlands)

    Baele, L.T.M.; Bekaert, G.R.J.; Cho, S.; Inghelbrecht, K.; Moreno, A.

    2015-01-01

    A New-Keynesian macro-model is estimated accommodating regime-switching behavior in monetary policy and macro-shocks. A key to our estimation strategy is the use of survey-based expectations for inflation and output. Output and inflation shocks shift to the low volatility regime around 1985 and 1990

  2. Regime change?

    International Nuclear Information System (INIS)

    Following the 1998 nuclear tests in South Asia and later reinforced by revelations about North Korean and Iraqi nuclear activities, there has been growing concern about increasing proliferation dangers. At the same time, the prospects of radiological/nuclear terrorism are seen to be rising - since 9/11, concern over a proliferation/terrorism nexus has never been higher. In the face of this growing danger, there are urgent calls for stronger measures to strengthen the current international nuclear nonproliferation regime, including recommendations to place civilian processing of weapon-useable material under multinational control. As well, there are calls for entirely new tools, including military options. As proliferation and terrorism concerns grow, the regime is under pressure and there is a temptation to consider fundamental changes to the regime. In this context, this paper will address the following: Do we need to change the regime centered on the Treaty on the Nonproliferation of Nuclear Weapons (NPT) and the International Atomic Energy Agency (IAEA)? What improvements could ensure it will be the foundation for the proliferation resistance and physical protection needed if nuclear power grows? What will make it a viable centerpiece of future nonproliferation and counterterrorism approaches?

  3. Competition Regime

    OpenAIRE

    Danilo Icaza Ortiz

    2013-01-01

    This paper is a review of the competition regime works of various authors, published under the auspices of the University of the Hemispheres and the Corporation for Studies and Publications. Analyzes the structure, the general concepts, case law taken for development. Includes comments on the usefulness of this work for the study of competition law and the contribution to the lawyers who want to practice in this branch of economic law.

  4. Competition Regime

    Directory of Open Access Journals (Sweden)

    Danilo Icaza Ortiz

    2013-01-01

    Full Text Available This paper is a review of the competition regime works of various authors, published under the auspices of the University of the Hemispheres and the Corporation for Studies and Publications. Analyzes the structure, the general concepts, case law taken for development. Includes comments on the usefulness of this work for the study of competition law and the contribution to the lawyers who want to practice in this branch of economic law.

  5. Multiobjective fuel management optimization for self-fuel-providing LMFBR using genetic algorithms

    Energy Technology Data Exchange (ETDEWEB)

    Toshinsky, Vladimir G.; Sekimoto, Hiroshi [Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, O-Okayama, Meguro-ku, Tokyo (Japan); Toshinsky, Georgy I. [State Scientific Center, Institute of Physics and Power Engineering, Obninsk (Russian Federation)

    1999-06-01

    One of the conceptual options under consideration for the future of nuclear power is the long-term development without fuel reprocessing. This concept is based on a reactor that requires no plutonium reprocessing for itself, and provides high efficiency of natural uranium utilization, so called Self-Fuel-Providing LMFBR (SFPR). Several design considerations were previously given to this reactor type which, however, suffer from some problems connected with insufficient power flattening, large reactivity swings during burnup cycles, and peak fuel burnup being significantly higher than recent technology experience, which is about 18% for U-10 wt%Zr metallic fuel to be considered. Yet, the mentioned core parameters demonstrate high sensitivity to the fuel management strategy selected for the reactor. Therefore, the aim of this study is to develop a practical tool for the improvement of the core characteristics by fuel management optimization, which is based on advanced optimization techniques such as Genetic Algorithms (GA). The calculation results obtained by a simplified reactor model can serve as estimates of achievable values for mentioned core parameters, which are necessary to make decisions at the preliminary optimization stage.

  6. 232Th、233U、238Pu、240Pu、242Pu、241Am、242Cm、243Cm和244Cm的裂变释放热能研究%Thermal Energy Released in Fission of 232 Th,233 U,238 Pu, 240 Pu,242 Pu,241 Am,242 Cm,243 Cm and 244 Cm

    Institute of Scientific and Technical Information of China (English)

    赵艳飞; 马续波; 陈义学

    2013-01-01

    In the nuclear reactor design ,the precise calculation of thermal fission energy is of great significance .In the pressurized water reactor ,high energy neutron-induced fission rarely occurs ,the isotopes including 233 U ,241 Am and 243 Cm are mostly induced by thermal neutrons ,while the other isotopes such as 232Th ,238Pu ,240Pu ,242Pu ,242Cm and 244 Cm are by fast neutron . In order to carry out this work , the nuclear data extracted from the latest evaluated nuclear data file (ENDF/B-Ⅶ ) were adopted ,and the energy-conservation law for the calculation of total fission energy were used , meanw hile ,with the consideration of capture energy and the correction of βand γ ,the thermal fission energy of nine isotopes was obtained .Compared with the data excerpted from IAEA issued WIMS-D database ,the results are reasonable .The thermal fission energy and its uncertainties of the nine isotopes are :(193.939 ± 0.176) MeV for 232 Th , (200.063 ± 0.084) MeV for 233 U ,(208.786 ± 1.133 ) MeV for 238 Pu ,(211.266 ± 0.220 ) MeV for 240 Pu ,(213.862 ± 0.299 ) MeV for 242 Pu ,(215.077 ± 0.210 ) MeV for 241 Am ,(218.821 ± 0.159) MeV for 242Cm ,(218.525 ± 0.388) MeV for 243Cm ,and (220.067 ± 0.131) MeV for 244 Cm ,respectively .%在核反应堆设计中,对每次裂变释放热能进行精确计算具有重要意义。在压水堆内,高能中子诱发核裂变份额很小,233 U、241 Am、243 Cm主要由热中子诱发裂变,232 T h、238 Pu、240 Pu、242 Pu、242 Cm、244 Cm主要由快中子诱发裂变。本文采用最新的核评价数据库 ENDF/B-Ⅶ,利用质量守恒法计算裂变释放总能,同时研究了中微子带走的能量,中子俘获能及β、γ修正项,最终给出了9种核素裂变释放热能。与IAEA颁布的WIMS-D格式数据库中的裂变释放热能数据的对比表明,本文所用方法计算结果合理。9种核素每次裂变释放热能分别为:232 Th ,(193.939±0.176) MeV ;233 U ,(200.063

  7. Sustainable urban regime adjustments

    DEFF Research Database (Denmark)

    Quitzau, Maj-Britt; Jensen, Jens Stissing; Elle, Morten;

    2013-01-01

    The endogenous agency that urban governments increasingly portray by making conscious and planned efforts to adjust the regimes they operate within is currently not well captured in transition studies. There is a need to acknowledge the ambiguity of regime enactment at the urban scale. This directs......, inspired by Actor-Network Theory to demonstrate that regime incumbent actors can induce gradual regime adjustments at the urban scale. This is done through a case study of an urban development project, where the Municipality of Egedal in Denmark has successfully promoted energy efficient buildings through...

  8. Measuring autocratic regime stability

    Directory of Open Access Journals (Sweden)

    Joseph Wright

    2016-01-01

    Full Text Available Researchers measure regime stability in autocratic contexts using a variety of data sources that capture distinct concepts. Often this research uses concepts developed for the study of democratic politics, such as leadership change or institutionalized authority, to construct measures of regime breakdown in non-democratic contexts. This article assesses whether the measure a researcher chooses influences the results they obtain by examining data on executive leadership, political authority, and autocratic regimes. We illustrate the conceptual differences between these variables by extending recent studies in the literature on the political consequences of non-tax revenue and unearned foreign income.

  9. A method to improve multiobjective genetic algorithm optimization of a self-fuel-providing LMFBR by niche induction among nondominated solutions

    Energy Technology Data Exchange (ETDEWEB)

    Toshinsky, Vladimir G.; Sekimoto, Hiroshi E-mail: hsekimot@nr.titech.ac.jp; Toshinsky, Georgy I

    2000-03-01

    A method to improve the optimization performance of a genetic algorithm (GA) for multiobjective optimization problems is proposed. It is based on niche induction among nondominated solutions that is fulfilled by the control on their reproduction potential by using a sharing function. It is applied to an equilibrium cycle fuel reloading pattern for a Self-Fuel-Providing Reactor, and it provides better results compared to ones obtained with an adaptation of a conventional method.

  10. THE INFLUENCED FLOW REGIMES

    Directory of Open Access Journals (Sweden)

    Gavril PANDI

    2011-03-01

    Full Text Available The influenced flow regimes. The presence and activities ofhumanity influences the uniform environmental system, and in this context, therivers water resources. In concordance with this, the natural runoff regime suffersbigger and deeper changes. The nature of these changes depending on the type anddegree of water uses. The multitude of the use cause different types of influence,whit different quantitative aspects. In the same time, the influences havequalitative connotations, too, regarding to the modifications of the yearly watervolume runoff. So the natural runoff regime is modified. After analyzing thedistribution laws of the monthly runoff, there have been differenced four types ofinfluenced runoff regimes. In the excess type the influenced runoff is bigger thanthe natural, continuously in the whole year. The deficient type is characterized byinverse rapports like the first type, in the whole year. In the sinusoidal type, theinfluenced runoff is smaller than the natural in the period when the water isretained in the lake reservoirs, and in the depletion period the situation inverts. Atthe irregular type the ratio between influenced and natural runoff is changeable ina random meaner monthly. The recognition of the influenced regime and the gradeof influence are necessary in the evaluation and analysis of the usable hydrologicalriver resources, in the flood defence activities, in the complex scheme of thehydrographic basins, in the environment design and so on.

  11. World Nonproliferation Regime

    Institute of Scientific and Technical Information of China (English)

    Ouyang Liping; Wu Xingzuo

    2007-01-01

    2006 witnessed an intense struggle between nuclear proliferation and nonproliferation. Iran's nuclear issue and North Korea's nuclear test have cast a deep shadow over the current international nonproliferation regime. The international contest for civil nuclear development became especially fierce as global energy prices went up. Such a situation , to some extent, accelerated the pace of nuclear proliferation. Furthermore, the existing international nonproliferation regime, based upon the Nuclear Nonproliferation Treaty (NPT), was affected by loopholes, and the U.S. failed in its ambition to unite other forces to mend fences. The international community needs to come up with a comprehensive and long-term strategy to meet the demand for an effective future nonproliferation regime in a healthy nuclear order.

  12. Supply regimes in fisheries

    DEFF Research Database (Denmark)

    Nielsen, Max

    2006-01-01

    -economic supply model with mesh sizes is developed. It is found that in the presence of realistic management schemes, the supply curves are close to vertical in the relevant range. Also, the supply curve under open access with mesh size limitations is almost vertical in the relevant range, owing to constant......Supply in fisheries is traditionally known for its backward bending nature, owing to externalities in production. Such a supply regime, however, exist only for pure open access fisheries. Since most fisheries worldwide are neither pure open access, nor optimally managed, rather between the extremes......, the traditional understanding of supply regimes in fisheries needs modification. This paper identifies through a case study of the East Baltic cod fishery supply regimes in fisheries, taking alternative fisheries management schemes and mesh size limitations into account. An age-structured Beverton-Holt based bio...

  13. Dimagrire in regime mediatico

    OpenAIRE

    Boutaud, Jean-Jacques

    2012-01-01

    publication en italien : BOUTAUD Jean-Jacques, « Dimagrire in regime mediatico », Dietetica e semiotica. Regimi di Senso, a cura di Dario Mangano e Gianfranco Marrone, Mimesis Edizioni, Milano, 2013, p. 19-38 Il titolo può leggersi in molti modi. Per esempio: dietetica e semiotica sono due regimi di senso, uno alimentare e l'altro comunicativo, con pari dignità, dunque da paragonare fra loro. Oppure: grazie alla semiotica la dietetica appare, non più come un regime alimentare, ma come un r...

  14. Political Regimes and Economic Growth

    Directory of Open Access Journals (Sweden)

    Carlos Pinho

    2009-12-01

    Full Text Available Are political regimes drivers of economic growth? While political institutions are influenced by economic development, they are in turn a key determinant of the development process. This study builds in the Neoclassical Growth theory to identify the influence of political regimes on economic development through a panel data sample of 170 countries from 1960 to 2000. Results suggest that once fixed effects are considered, the positive relationship between income per capita and political regimes measured by different democracy variables disappears.

  15. Unitary Housing Regimes in Transition

    DEFF Research Database (Denmark)

    Bengtsson, Bo; Jensen, Lotte

    2013-01-01

    to the Danish and Swedish housing regimes are analysed and the responses and outcomes in terms of policy change and/or institutional continuity (path dependence) are compared. Overall, the more decentralized Danish housing regime seems to have resisted pressures for change and retrenchment better so far than...

  16. 'Regime shopping' across (blurring) boundaries

    NARCIS (Netherlands)

    Houwerzijl, M.S.; Evju, Stein

    2014-01-01

    This book chapter identifies and explores the (blurring) boundaries between the legal regimes for labour mobility across the EU. In the context of - what is sometimes called - 'regime shopping' a close look is taken into the law on freedom of movement within the EU. Several categories of transnation

  17. Regime shifts in resource management

    NARCIS (Netherlands)

    de Zeeuw, A.J.

    2014-01-01

    Resource management has to take account of the possibility of tipping points and regime shifts in ecological systems that provide the resources. This article focuses on the typical model of regime shifts in the ecological literature and analyzes optimal management and common-property issues when tra

  18. The Choice of Monetary Regime

    DEFF Research Database (Denmark)

    Østrup, Finn

    , a comparisonbetween monetary regimes suggests that welfare is highest under nominalincome targeting where the nominal income target is determined to bring aboutprice stability.Keywords: Monetary regimes; fiscal policy; monetary non-neutrality.JEL classicification: E42, E61, E62.......The article examines how government spending is determined in a closedeconomy where the nominal wage is pre-set through contracts and the wage settershave perfect foresight regarding subsequent policy decisions. The monetaryregime affects government spending because: (i) with a pre-set nominal wage......, agiven change in government spending has different effects on employment andinflation under different monetary regimes, and (ii) the authorities' inclinationto expand government spending is affected by the inflation rate which dependson the monetary regime. If the costs related to inflation are high...

  19. MULTILATERAL DIPLOMACY AND INTERNATIONAL REGIMES

    Directory of Open Access Journals (Sweden)

    BENEA Ciprian-Beniamin

    2014-12-01

    Full Text Available The history of diplomacy can by divided in three main periods: one is that of occasional diplomacy peculiar to Middle Ages, while other belong to permane diplomacy, peculiar to modern times. But this one can be divided in two parts, too: one with a bilateral character, previos to 1st World War, and one with a multilateral character, manifested especially after the end on 1st World War. This third type is the focus of present paper. And it cannot be separated from the newly international constructs: international regimes, and international organizations. International instritutions the area where international regimes are belonging to – are legal constructs which provide the formal (and legal framework for continous negotiations. They are the most visible part of the new diplomacy – the one which has a permanent character, and it has an more open face. Anyway, the most important connection has to do with the international institutions, international regimes, and multilateral international negotiations. In the era of the new diplomacy, they all have a permanent character. International institutions help international negotiations carring on; while in their turn, they provide the base for international regimes’ creation, and especially for their evolution. The international regimes’ evolution is an inseparable part of a permanent international framework. And if there is missing a permanent international framework (international organization connected to a specific regime, this regime is a difuse one, its members have only informal relations among them, while they survey each other, looking at their behavior, but they don’t have a formal relationship among them, which could help them solving their future common interests, and protect them from their common fears. International regimes are very important in the era when evrithing touches, and influences everything. In the same time, the complexity of our present world can be successfully

  20. Great Lakes' regional climate regimes

    Science.gov (United States)

    Kravtsov, Sergey; Sugiyama, Noriyuki; Roebber, Paul

    2016-04-01

    We simulate the seasonal cycle of the Great Lakes' water temperature and lake ice using an idealized coupled lake-atmosphere-ice model. Under identical seasonally varying boundary conditions, this model exhibits more than one seasonally varying equilibrium solutions, which we associate with distinct regional climate regimes. Colder/warmer regimes are characterized by abundant/scarce amounts of wintertime ice and cooler/warmer summer temperatures, respectively. These regimes are also evident in the observations of the Great Lakes' climate variability over recent few decades, and are found to be most pronounced for Lake Superior, the deepest of the Great Lakes, consistent with model predictions. Multiple climate regimes of the Great Lakes also play a crucial role in the accelerated warming of the lakes relative to the surrounding land regions in response to larger-scale global warming. We discuss the physical origin and characteristics of multiple climate regimes over the lakes, as well as their implications for a longer-term regional climate variability.

  1. Cloud regimes as phase transitions

    Science.gov (United States)

    Stechmann, Samuel N.; Hottovy, Scott

    2016-06-01

    Clouds are repeatedly identified as a leading source of uncertainty in future climate predictions. Of particular importance are stratocumulus clouds, which can appear as either (i) closed cells that reflect solar radiation back to space or (ii) open cells that allow solar radiation to reach the Earth's surface. Here we show that these clouds regimes -- open versus closed cells -- fit the paradigm of a phase transition. In addition, this paradigm characterizes pockets of open cells as the interface between the open- and closed-cell regimes, and it identifies shallow cumulus clouds as a regime of higher variability. This behavior can be understood using an idealized model for the dynamics of atmospheric water as a stochastic diffusion process. With this new conceptual viewpoint, ideas from statistical mechanics could potentially be used for understanding uncertainties related to clouds in the climate system and climate predictions.

  2. Friction Regimes in the Lubricants Solid-State Regime

    NARCIS (Netherlands)

    Schipper, D.J.; Maathuis, O.; Dowson, D.; Taylor, C.M.; Childs, T.H.C.; Dalmaz, G.

    1995-01-01

    Friction measurements were performed in the lubricant's solid-state regime to study the transition from full-film lubrication, in which the separation is maintained by a solidified lubricant, to mixed lubrication. Special attention is paid to the influence of temperature (inlet viscosity) and roughn

  3. On the regimes of premixing

    Energy Technology Data Exchange (ETDEWEB)

    Angelini, S.; Theofanous, T.G.; Yuen, W.W. [California Univ., Santa Barbara, CA (United States). Center for Risk Studies and Safety

    1998-01-01

    The conditions of the MAGICO-2000 experiment are extended to more broadly investigate the regimes of premixing, and the corresponding internal structures of mixing zones. With the help of the data and numerical simulations using the computer code PM-ALPHA, we can distinguish extremes of behavior dominated by inertia and thermal effects - we name these the inertia and thermal regimes, respectively. This is an important distinction that should guide future experiments aimed at code verification in this area. Interesting intermediate behaviors are also delineated and discussed. (author)

  4. Monetary regimes in open economies

    NARCIS (Netherlands)

    Korpos, A.

    2006-01-01

    This thesis presents a two-country open economy framework for the analysis of strategic interactions among monetary authorities and wage bargaining institutions. From this perspective, the thesis investigates the economic consequences of replacing flexible and fixed exchange rate regimes with a mone

  5. Friction Regimes in the Lubricants Solid-State Regime

    OpenAIRE

    Schipper, D.J.; Maathuis, O.; Dowson, D; Taylor, C.M.; Childs, T.H.C.; Dalmaz, G.

    1995-01-01

    Friction measurements were performed in the lubricant's solid-state regime to study the transition from full-film lubrication, in which the separation is maintained by a solidified lubricant, to mixed lubrication. Special attention is paid to the influence of temperature (inlet viscosity) and roughness on this transition. The friction measurements showed that in the lubricants solid-state region three lubrication modes can be distinguished: A) full-film lubrication; separation is maintained b...

  6. The Concept of Truth Regime

    Directory of Open Access Journals (Sweden)

    Lorna Weir

    2008-07-01

    Full Text Available “Truth regime” is a much used but little theorized concept, with the Foucauldian literature presupposing that truth in modernity is uniformly scientific/quasi-scientific and enhances power. I argue that the forms of truth characteristic of our present are wider than Foucault recognized, their relations to power more various, and their historicity more complex. The truth regime of advanced modernity is characterized by multiple, irreducible truth formulae that co-exist and sometimes vie for dominance. A truth formula stabilizes a network of elements: a relation between representation and presentation (words and things, truth and non-truth, and the place of the subject in discourse. Our contemporary truth regime comprises radically heterogeneous truthful knowledges – science, governance, religion/politics, and common culture – that have distinct histories and relations to power.

  7. Demystifying optimal dynamic treatment regimes.

    Science.gov (United States)

    Moodie, Erica E M; Richardson, Thomas S; Stephens, David A

    2007-06-01

    A dynamic regime is a function that takes treatment and covariate history and baseline covariates as inputs and returns a decision to be made. Murphy (2003, Journal of the Royal Statistical Society, Series B 65, 331-366) and Robins (2004, Proceedings of the Second Seattle Symposium on Biostatistics, 189-326) have proposed models and developed semiparametric methods for making inference about the optimal regime in a multi-interval trial that provide clear advantages over traditional parametric approaches. We show that Murphy's model is a special case of Robins's and that the methods are closely related but not equivalent. Interesting features of the methods are highlighted using the Multicenter AIDS Cohort Study and through simulation. PMID:17688497

  8. The EU Commission consultation regime

    OpenAIRE

    Quittkat, Christine; Finke, Barbara

    2008-01-01

    "The present consultation regime of the European Commission is marked by the role the Commission assigns to non-governmental actors or civil society organisations (CSOs). The Commission's documents on its policy of consultation and cooperation with external non-governmental actors reveal that a reflective approach has emerged during the 1980s, referring to a more elaborate concept of 'good governance'. The gradual extension is most noticeable in the change of terminology, from ‘consultation’ ...

  9. The International Climate Change Regime

    Science.gov (United States)

    Yamin, Farhana; Depledge, Joanna

    2005-01-01

    Aimed at the increasing number of policy-makers, stakeholders, researchers, and other professionals working on climate change, this volume presents a detailed description and analysis of the international regime established in 1992 to combat the threat of global climate change. It provides a comprehensive accessible guide to a high-profile area of international law and politics, covering not only the obligations and rights of countries, but ongoing climate negotiations as well.

  10. Disclosure regimes and corporate governance

    OpenAIRE

    Wüstemann, Jens

    2004-01-01

    As there is a strong relationship of disclosure regimes and corporate governance the internationally varying distribution of information rights can be interpreted as a function of different systems of corporate governance. A disclosure system comprises all legally recognized information claims that a system of corporate governance or a financial system furnishes financial contracting parties with: Both public disclosure and disclosure via private information channels may serve value-relevant ...

  11. Exchange Rate Regimes and Location

    OpenAIRE

    Ricci, Luca Antonio

    1997-01-01

    This paper investigates the effects of fixed versus flexible exchange rate regimes on location choices of firms and on the degree of specialization of countries. In a two-country two-differentiated-good monetary model, demand, supply, and monetary shocks arise after wages are set and prices are optimally chosen. The exchange rate performs then an adjustment role for firms located in the country relatively specialized in the good they produce, but it constitutes a factor of disturbance for the...

  12. Exchange rate regimes and monetary arrangements

    Directory of Open Access Journals (Sweden)

    Ivan Ribnikar

    2005-06-01

    Full Text Available There is a close relationship between a country’s exchange rate regime and monetary arrangement and if we are to examine monetary arrangements then exchange rate regimes must first be analysed. Within the conventional and most widely used classification of exchange rate regimes into rigid and flexible or into polar regimes (hard peg and float on one side, and intermediate regimes on the other there, is a much greater variety among intermediate regimes. A more precise and, as will be seen, more useful classification of exchange rate regimes is the first topic of the paper. The second topic is how exchange rate regimes influence or determine monetary arrangements and monetary policy or monetary policy regimes: monetary autonomy versus monetary nonautonomy and discretion in monetary policy versus commitment in monetary policy. Both topics are important for countries on their path to the EU and the euro area

  13. Merging of Rhine flow regimes

    Science.gov (United States)

    Boessenkool, Berry; Bronstert, Axel; Bürger, Gerd

    2016-04-01

    The Rhine flow regime is changing: (a) in the alpine nival regime, snow melt floods occur earlier in the year and (b) in the pluvial middle-Rhine regime, rainfall induced flood magnitudes rise. The seasonality of each is currently separated in time, but it is conceivable that this may shift due to climate change. If extremes of both flood types coincide, this would create a new type of hydrologic extreme with disastrous consequences. Quantifying the probability for a future overlap of pluvial and nival floods is therefore of high relevance to society and particularly to reinsurance companies. In order to investigate possible changes in magnitude and timing of flood types, we are developing a chain of physical models for spatio-temporal combination of flood probabilities. As input, we aim to use stochastically downscaled temperature and rainfall extremes from climate model weather projections. Preliminary research shows a six-week forward-shift of peak discharge at the nival gauge Maxau in the past century. The aim of presenting our early-stage work as a poster is to induce an exchange of ideas with fellow scientists in close research disciplines.

  14. Alberta oil sands royalty regime

    International Nuclear Information System (INIS)

    The long term objective of the Oil Sands Business Unit of Alberta Energy is to pave the way for Alberta's bitumen production to reach 3 million barrels per day by 2020. This presentation described the national government's role in resource development. It was emphasized that since the Crown is the owner of the oil sands resource, it would benefit by providing strategic leadership and by generating a larger royalty base. The oil sands fiscal regime was described with reference to generic royalty, risk sharing, investment, and project economics. Business rule principles were also outlined along with criteria for project expansions. Both upstream and downstream challenges and opportunities were listed. 4 figs

  15. Accommodating human values in the climate regime

    NARCIS (Netherlands)

    Cook, Rosalind; Tauschinsky, Eljalill

    2008-01-01

    The climate regime addresses one of the most important challenges facing humankind today. However, while the environmental and economic sides of the problem are well represented, it lacks the inclusion of social and human aspects. The human rights regime, in contrast, is a regime which has been esta

  16. Adaptation in Collaborative Governance Regimes

    Science.gov (United States)

    Emerson, Kirk; Gerlak, Andrea K.

    2014-10-01

    Adaptation and the adaptive capacity of human and environmental systems have been of central concern to natural and social science scholars, many of whom characterize and promote the need for collaborative cross-boundary systems that are seen as flexible and adaptive by definition. Researchers who study collaborative governance systems in the public administration, planning and policy literature have paid less attention to adaptive capacity specifically and institutional adaptation in general. This paper bridges the two literatures and finds four common dimensions of capacity, including structural arrangements, leadership, knowledge and learning, and resources. In this paper, we focus on institutional adaptation in the context of collaborative governance regimes and try to clarify and distinguish collaborative capacity from adaptive capacity and their contributions to adaptive action. We posit further that collaborative capacities generate associated adaptive capacities thereby enabling institutional adaptation within collaborative governance regimes. We develop these distinctions and linkages between collaborative and adaptive capacities with the help of an illustrative case study in watershed management within the National Estuary Program.

  17. Measuring the effectiveness of international environmental regimes

    Energy Technology Data Exchange (ETDEWEB)

    Helm, C.; Sprinz, D.F.

    1999-05-01

    While past research has emphasized the importance of international regimes for international governance, systematic assessments of regime effects are missing. This article derives a standardized measurement concept for the effectiveness of international environmental regimes by developing an operational rational choice calculus to evaluate actual policy simultaneously against a non-regime counterfactual and a collective optimum. Subsequently, the empirical feasibility of the measurement instrument is demonstrated by way of two international treaties regulating transboundary air pollution in Europe. The results demonstrate that the regimes indeed show positive effects - but fall substantially short of the collective optima. (orig.)

  18. Regime Jumps in Electricity Prices

    International Nuclear Information System (INIS)

    Electricity prices are known to be very volatile and subject to frequent jumps due to system breakdown, demand shocks, and inelastic supply. As many international electricity markets are in some state of deregulation, more and more participants in these markets are exposed to these stylised facts. Appropriate pricing, portfolio, and risk management models should incorporate these facts. Authors have introduced stochastic jump processes to deal with the jumps, but we argue and show that this specification might lead to problems with identifying the true mean-reversion within the process. Instead, we propose using a regime jump model that disentangles mean-reversion from jump behaviour. This model resembles more closely the true price path of electricity prices

  19. Propagation Regime of Iron Dust Flames

    Science.gov (United States)

    Tang, Francois-David; Goroshin, Samuel; Higgins, Andrew J.

    2012-01-01

    A flame propagating through an iron-dust mixture can propagate in two asymptotic regimes. When the characteristic time of heat transfer between particles is much smaller than the characteristic time of particle combustion, the flame propagates in the continuum regime where the heat released by reacting particles can be modelled as a space-averaged function. In contrast, when the characteristic time of heat transfer is much larger than the particle reaction time, the flame can no longer be treated as a continuum due to dominating effects associated with the discrete nature of the particle reaction. The discrete regime is characterized by weak dependence of the flame speed on the oxygen concentration compared to the continuum regime. The discrete regime is observed in flames propagating through an iron dust cloud within a gas mixture containing xenon, while the continuum regime is obtained when xenon is substituted with helium.

  20. Accommodating human values in the climate regime

    Directory of Open Access Journals (Sweden)

    Rosalind Cook

    2008-12-01

    Full Text Available The climate regime addresses one of the most important challenges facing humankind today. However, while the environmental and economic sides of the problem are well represented, it lacks the inclusion of social and human aspects. The human rights regime, in contrast, is a regime which has been established precisely to implement human values. This article ex-plains the problems of climate change in terms of human values and argues that some proce-dures from the human rights regime offer possibilities for improvement. It is submitted that through the inclusion of human rights instruments, such as individual communication, pro-gressive realisation and authoritative interpretation, the inclusion of human values into the climate regime will be facilitated. This article presents these instruments and discusses their potential for inclusion in the climate regime.

  1. Commodity Price Volatility Across Exchange Rate Regimes

    OpenAIRE

    John T. Cuddington; Hong Liang

    1998-01-01

    This paper documents a new "stylized fact" regarding commodity prices using alternative datasets covering the period from 1880 to 1996: The volatility of real commodity prices, defined as nominal commodity prices deflated by the manufacturing unit value index, is higher under flexible-exchange rate regimes than fixed-exchange rate regimes. Furthermore, changes in exchange regime are associated with changes in the persistence of commodity price shocks. Implications of this finding for open-eco...

  2. US Forest Service LANDFIRE Historical Fire Regimes

    Data.gov (United States)

    US Forest Service, Department of Agriculture — Historical fire regimes, intervals, and vegetation conditions are mapped using the Vegetation Dynamics Development Tool (VDDT). These data support fire and...

  3. Synergies between nonproliferation regimes: A pragmatic approach

    International Nuclear Information System (INIS)

    Full text: With the recent progress in establishing international nonproliferation regimes, the question of synergies between different verification and monitoring regimes is becoming more acute. Three multilateral and universal nonproliferation organisations covering safeguards on civil nuclear materials, nuclear testing, and chemical weapons are up and running. A regime on biological weapons is under negotiation. Several regional organisations concerned with monitoring nonproliferation commitments in the nuclear field are in place; others are being established. Past discussions on synergies between these regimes have suffered from being too far-reaching. These discussions often have not reflected adequately the political difficulties of cooperation between regimes with different membership, scope and institutional set-up. This paper takes a pragmatic look at exploiting synergies and identifies some potential and real overlaps in the work between different verification regimes. It argues for a bottom-up approach and identifies building blocks for collaboration between verification regimes. By realising such, more limited potential for cooperation, the ground could be prepared for exploiting other synergies between these regimes. (author)

  4. Capacitance densitometer for flow regime identification

    Science.gov (United States)

    Shipp, Jr., Roy L.

    1978-01-01

    This invention relates to a capacitance densitometer for determining the flow regime of a two-phase flow system. A two-element capacitance densitometer is used in conjunction with a conventional single-beam gamma densitometer to unambiguously identify the prevailing flow regime and the average density of a flowing fluid.

  5. LEGAL MATRIMONIAL REGIME IN B&H

    Directory of Open Access Journals (Sweden)

    Boris Krešić

    2011-12-01

    Full Text Available Matrimonial regime between spouses or between extramarital partners, and between parents and children is regulated by the Family Law Act of Bosnia and Herzegovina Federation, hereinafter FLA B&HF (SG FBiH 35/05, 41/05, Family Law Act of the Republic of Srpska, hereinafter FLA RS (SG RS”54/02, 41/08 and the Family Law Act of Brčko District, hereinafter FLA BD (SG RS, 66/07. Legal rules used for the regulation of the matrimonial regime between spouses, as well as between spouses and third parties make matrimonial regime (Ponjavić, 2005, p. 361. Matrimonial regime between spouses in family legislation in Bosnia and Herzegovina (B&H is regulated in two following ways: as legal matrimonial regime and as contract matrimonial regime. Legal regime is the one which applies on spouses if not arranged otherwise prior to contracting marriage or during marriage. In this paper the author indicates the differences between the legal matrimonial regimes of the two entities as well as those between the entities and Brčko District of Bosnia and Herzegovina.

  6. Explaining the Transition Between Exchange Rate Regimes

    OpenAIRE

    Masson, Paul; RUGE-MURCIA, Francisco J.

    2003-01-01

    This paper studies the transition between exchange rate regimes using a Markov chain model with time-varying transition probabilities. The probabilities are parameterized as nonlinear functions of variables suggested by the currency crisis and optimal currency area literature. Results using annual data indicate that inflation, and to a lesser extent, output growth and trade openness help explain the exchange rate regime transition dynamics.

  7. Multiscale regime shifts and planetary boundaries

    NARCIS (Netherlands)

    Hughes, T.P.; Carpenter, S.; Rockstrom, J.; Scheffer, M.; Walker, B.

    2013-01-01

    Life on Earth has repeatedly displayed abrupt and massive changes in the past, and there is no reason to expect that comparable planetary-scale regime shifts will not continue in the future. Different lines of evidence indicate that regime shifts occur when the climate or biosphere transgresses a ti

  8. LOW DOSE MAGNESIUM SULPHATE REGIME FOR ECLAMPSIA

    Directory of Open Access Journals (Sweden)

    Bangal V

    2009-09-01

    Full Text Available Pre- eclampsia is one of the commonest medical complications seen during pregnancy. It contributes significantly to maternal and perinatal morbidity and mortality. Dr.J.A.Pritchard in 1955, introduced magnesium sulphate for control of convulsions in eclampsia and is used worldwide. Considering the low body mass index of indian women, a low dose magnesium sulphate regime has been introduced by some authors. Present study was carried out at tertiary care centre in rural area. Fifty cases of eclampsia were randomly selected to find out the efficacy of low dose magnesium sulphate regime to control eclamptic convulsions. Maternal and perinatal outcome and magnesium toxicity were analyzed. It was observed that 86% cases responded to initial intravenous dose of 4 grams of 20% magnesium sulphate . Eight percent cases, who got recurrence of convulsion, were controlled by additional 2 grams of 20% magnesium sulphate. Six percent cases required shifting to standard Pritchard regime, as they did not respond to low dose magnesium sulphate regime. The average total dose of magnesium sulphate required for control of convulsions was 20 grams ie. 54.4% less than that of standard Pritchard regime. The maternal and perinatal morbidity and mortality in the present study werecomparable to those of standard Pritchard regime. The study did not find a single case of magnesium related toxicity with low dose magnesium sulphate regime. Low dose magnesium sulphate regime was found to be safe and effective in eclampsia.

  9. Framing of regimes and transition strategies

    DEFF Research Database (Denmark)

    Jensen, Jens Stissing

    2012-01-01

    This article suggests that transition strategies are always formulated in the context of specific representations of the regime and the challenges it faces. It is argued that the framing of a regime affects the envisioning of transition strategies. An analysis of the current development agenda...

  10. Food Regimes Revisited: A New Zealand Perspective

    Directory of Open Access Journals (Sweden)

    Michael Roche

    2012-01-01

    Full Text Available ‘Food Regimes’ was coined by Friedmann and McMichael in 1989 and provided a organising framework for a considerable amount of Australian and New Zealand research during a period of economic restructuring and ‘deregulation’. Subsequently Food regimes were overtaken by other perspectives in New Zealand and elsewhere including an interest in commodity productions chains, regulation, post-productivist landscapes, and post structural political economy. More recently McMichael has reintroduced Food Regimes to his analysis. The paper will compare and contrast McMichael’s earlier and more recent engagements with Food Regimes. The export meat, the dairy, and pip fruit industries of Zealand it will be used to illustrate points about the timing, boundaries and margins as well as the transformation of Food Regimes. Finally the paper will attempt to connect the more recent focus on commodity chain analysis and post productivist landscapes with McMichael’s renewed interest in food Regimes.

  11. What is the economy of Ancien Regime?

    OpenAIRE

    Jean-Yves Grenier

    2012-01-01

    The aim of this article is to describe the main features of the Ancien Regime economy and develop a “political economy” of European societies, particularly the French, during the central period of modernity (XVII-XVIII centuries

  12. Earth Regime Network Evolution Study (ERNESt)

    Science.gov (United States)

    Menrad, Bob

    2016-01-01

    Speaker and Presenter at the Lincoln Laboratory Communications Workshop on April 5, 2016 at the Massachusetts Institute of Technology Lincoln Laboratory in Lexington, MA. A visual presentation titled Earth Regimes Network Evolution Study (ERNESt).

  13. FLOW REGIMES BELOW AERATORS FOR DISCHARGE TUNNELS

    Institute of Scientific and Technical Information of China (English)

    MA Fei; WU Jian-hua

    2012-01-01

    The flow regimes below an aerator influence directly the air entrainment and the cavitation damage control.Based on the theoretical considerations,the experiments of the aerator for a discharge tunnel were conducted,and the relationships between the flow regime and hydraulic and geometric parameters were investigated.The results showed that,there are two kinds of threshold values for the flow regime conversions.One is Fr1-2 standing for the conversion from the fully filled cavity to the partially filled cavity,and the other is Fr2-3 which shows the change from the partially filled cavity to the net air cavity.Two empirical expressions were obtained for the conversions of the flow regimes,which can be used in the designs of the aerators.

  14. The Two Regimes of Postwar Shipping

    DEFF Research Database (Denmark)

    Iversen, Martin Jes; Tenold, Stig

    2014-01-01

    the bargaining that accompanied the shift from the national regime to the competitive regime. Specifically, we show that the new regime primarily accommodated the interests of private actors such as shipping companies, rather than the interests of the authorities and the trade unions.......The aim of this article is to illustrate the most important changes in the regulatory framework of the shipping sector from the 1960s to 2010, and to analyse the basis for, and effects of, these changes. In order to explain how the transformation has occurred, we use two traditional maritime...... nations—Denmark and Norway—as case studies. First, we introduce the two regimes of Danish and Norwegian shipping: ‘the national regime’ from the early 1960s to the mid-1970s; and ‘the competitive regime’, which was fully established by the middle of the 1990s and still persists. Then, we briefly sketch...

  15. Regimes of validity for balanced models

    Science.gov (United States)

    Gent, Peter R.; McWilliams, James C.

    1983-07-01

    Scaling analyses are presented which delineate the atmospheric and oceanic regimes of validity for the family of balanced models described in Gent and McWilliams (1983a). The analyses follow and extend the classical work of Charney (1948) and others. The analyses use three non-dimensional parameters which represent the flow scale relative to the Earth's radius, the dominance of turbulent or wave-like processes, and the dominant component of the potential vorticity. For each regime, the models that are accurate both at leading order and through at least one higher order of accuracy in the appropriate small parameter are then identified. In particular, it is found that members of the balanced family are the appropriate models of higher-order accuracy over a broad range of parameter regimes. Examples are also given of particular atmospheric and oceanic phenomena which are in the regimes of validity for the different balanced models.

  16. The international climate regime: towards consolidation collapse

    International Nuclear Information System (INIS)

    This article deals with the different modalities that exist to manage a problem of collective action in the field of climate negotiation. It uses two concepts of the International Political Economy (IPE): the concept of International Regime (IR) and the concept of Hegemony and / or Leadership. The course the international negotiation has taken between 1992 (Rio Convention) and march 2001 (the US rejection of the Kyoto Protocol of 1997) leads us, first, to question the conditions of existence as well as the viability of a non-hegemonic International Regime (Part One). Then, we discuss the perspectives for the 'post - Kyoto' era. After having examined the preferences of the three most active actors in the negotiation (USA, Europe, G77 + China) combined with the leadership capacities they possess, we identify three scenarios for the future: i) anarchy, ii) an international regime under the American hegemony, iii) an international regime under the European leadership (Part Two). (author)

  17. Developmental Regimes in Africa synthesis report

    OpenAIRE

    Booth, D.; Dietz, A.J.; Golooba-Mutebi, F.; Fuady, A.H.; Henley, D; Kelsall, T.; Leliveld, A.H.M.; Donge, van, J.K.

    2015-01-01

    Many African countries have experienced sustained economic growth, but few have achieved the type of structural change, driven by rising productivity, that has transformed mass living standards in parts of Asia. In the Developmental Regimes in Africa Synthesis Report, editor David Booth examines how DRA research has shed new light on how developmental regimes might emerge and be sustained in Africa in the 21st century. He outlines a concept with defining features at three levels: policy conte...

  18. Regime shifts and inflation uncertainty in Peru

    OpenAIRE

    Paúl Castillo; Alberto Humala; Vicente Tuesta

    2012-01-01

    The link between inflation and inflation uncertainty is evaluated using Peruvian data, in a context of changing monetary policies because of regime shifts. A Markov regime-switching heteroskedasticity model that includes unobserved components is used. The model shows how periods of high (low) inflation accompany periods of high (low) short- and long-run uncertainty in inflation. The results of the model also illustrate how, during the recent period of price stability in Peru, both permanent a...

  19. Contribution to the study of 233U production with MOX-ThPu fuel in PWR reactor. Transition scenarios towards Th/233U iso-generating concepts in thermal spectrum. Development of the MURE fuel evolution code

    International Nuclear Information System (INIS)

    If nuclear power is to provide a significant fraction of the growing world energy demand, only through the breeding concept can the development of sustainable nuclear energy become a reality. The study of such a transition, from present-day nuclear technologies to future breeding concepts is therefore pertinent. Among these future concepts, those using the thorium cycle Th/U-233 in a thermal neutron spectrum are of particular interest; molten-salt type thermal reactors would allow for breeding while requiring comparatively low initial inventories of U-233. The upstream production of U-233 can be obtained through the use of thorium-plutonium mixed oxide fuel in present-day light water reactors. This work presents, firstly, the development of the MURE evolution code system, a C++ object-oriented code that allows the study, through Monte Carlo (M.C.) simulation, of nuclear reactors and the evolution of their fuel under neutron irradiation. The M.C. methods are well-suited for the study of any reactor, whether it'd be an existing reactor using a new kind of fuel or a future concept altogether, the simulation is only dependent on nuclear data. Exact and complex geometries can be simulated and continuous energy particle transport is performed. MURE is an interface with MCNP, the well-known and validated transport code, that allows, among other functionalities, to simulate constant power and constant reactivity evolutions. Secondly, the study of MOX ThPu fuel in a conventional light water reactor (REP) is presented; it explores different plutonium concentrations and isotopic qualities in order to evaluate their safety characteristics. Simulation of their evolution allows us to quantify the production of U-233 at the end of burnup. Last, different french scenarios validating a possible transition towards a park of thermal Th/U-233 breeders, are presented. In these scenarios, U-233 is produced in ThPu moxed light water reactors. (author)

  20. Regime Diagrams for K-Theory Dispersion

    Science.gov (United States)

    Smith, Ronald B.

    2011-06-01

    In atmospheric dispersion, the "non-Gaussian" effects of gravitational settling, the vertical gradient in diffusivity and the surface deposition do not enter uniformly but rather break up parameter space into several discrete regimes. Here, we describe regime diagrams that are constructed for K-theory dispersion of effluent from a surface line source in unsheared inhomogeneous turbulence, using a previously derived Fourier-Hankel method. This K-theory formulation differs from the traditional one by keeping a non-zero diffusivity at the ground. This change allows for turbulent exchange between the canopy and the atmosphere and allows new natural length scales to emerge. The axes on the regime diagrams are non-dimensional distance defined as the ratio of downwind distance to the characteristic length scale for each effect. For each value of the ratio of settling speed to the K gradient, two to four regimes are found. Concentration formulae are given for each regime. The regime diagrams allow real dispersion problems to be categorized and the validity of end-state concentration formulae to be judged.

  1. Laser-Nucleus Interactions: The Quasiadiabatic Regime

    CERN Document Server

    Pálffy, Adriana; Hoefer, Axel; Weidenmüller, Hans A

    2015-01-01

    The interaction between nuclei and a strong zeptosecond laser pulse with coherent MeV photons is investigated theoretically. We provide a first semi-quantitative study of the quasiadiabatic regime where the photon absorption rate is comparable to the nuclear equilibration rate. In that regime, multiple photon absorption leads to the formation of a compound nucleus in the so-far unexplored regime of excitation energies several hundred MeV above the yrast line. The temporal dynamics of the process is investigated by means of a set of master equations that account for dipole absorption, stimulated dipole emission, neutron decay and induced fission in a chain of nuclei. That set is solved numerically by means of state-of-the-art matrix exponential methods also used in nuclear fuel burnup and radioactivity transport calculations. Our quantitative estimates predict the excitation path and range of nuclei reached by neutron decay and provide relevant information for the layout of future experiments.

  2. Fermi's golden rule beyond the Zeno regime

    Science.gov (United States)

    Debierre, Vincent; Goessens, Isabelle; Brainis, Edouard; Durt, Thomas

    2015-08-01

    We reconsider the problem of the spontaneous emission of light by an excited atomic state. We scrutinize the survival probability of this excited state for very short times, in the so-called Zeno regime, for which we show that the dynamics is dictated by a coherent, in-phase, response of the on-shell and off-shell vacuum modes. We also develop a perturbative approach in order to interpolate between different temporal regimes: the Zeno, golden rule (linear), and Wigner-Weisskopf (exponential) regimes. We compare results obtained with the E ̂.x ̂ and A ̂.p ̂ interaction Hamiltonians, using successively the dipole approximation and the exact coupling.

  3. Interpreting MAD within multiple accretion regimes

    CERN Document Server

    Mocz, Philip

    2014-01-01

    General relativistic magnetohydrodynamic (GRMHD) simulations of accreting black holes in the radiatively inefficient regime show that systems with sufficient magnetic poloidal flux become magnetically arrested disc (MAD) systems, with a well-defined relationship between the magnetic flux and the mass accretion rate. Recently, Zamaninasab (2014) report that the jet magnetic flux and accretion disc luminosity are tightly correlated over 7 orders of magnitude for a sample of 76 radio-loud active galaxies, concluding that the data are explained by the MAD mode of accretion. Their analysis assumes radiatively efficient accretion, and their sample consists primarily of radiatively efficient sources, while GRMHD simulations of MAD thus far have been carried out in the radiatively inefficient regime. We propose a model to interpret MAD systems in the context of multiple accretion regimes, and apply it to the sample in Zamaninasab (2014), along with additional radiatively inefficient sources from archival data. We sho...

  4. Regimes of turbulence without an energy cascade

    CERN Document Server

    Barenghi, C F; Baggaley, A W

    2016-01-01

    Experiments and numerical simulations of turbulent $^4$He and $^3$He-B have established that, at hydrodynamic length scales larger than the average distance between quantum vortices, the energy spectrum obeys the same 5/3 Kolmogorov law which is observed in the homogeneous isotropic turbulence of ordinary fluids. The importance of the 5/3 law is that it points to the existence of a Richardson energy cascade from large eddies to small eddies. However, there is also evidence of quantum turbulent regimes without Kolmogorov scaling. This raises the important questions of why, in such regimes, the Kolmogorov spectrum fails to form, what is the physical nature of turbulence without energy cascade, and whether hydrodynamical models can account for the unusual behaviour of turbulent superfluid helium. In this work we describe simple physical mechanisms which prevent the formation of Kolmogorov scaling in the thermal counterflow, and analyze the conditions necessary for emergence of quasiclassical regime in quantum tu...

  5. Early detection of ecosystem regime shifts

    DEFF Research Database (Denmark)

    Lindegren, Martin; Dakos, Vasilis; Groeger, Joachim P.;

    2012-01-01

    Critical transitions between alternative stable states have been shown to occur across an array of complex systems. While our ability to identify abrupt regime shifts in natural ecosystems has improved, detection of potential early-warning signals previous to such shifts is still very limited...... methods may have limited utility in ecosystem-based management as they show no or weak potential for early-warning. We therefore propose a multiple method approach for early detection of ecosystem regime shifts in monitoring data that may be useful in informing timely management actions in the face....... Using real monitoring data of a key ecosystem component, we here apply multiple early-warning indicators in order to assess their ability to forewarn a major ecosystem regime shift in the Central Baltic Sea. We show that some indicators and methods can result in clear early-warning signals, while other...

  6. Determination of the Hall Thruster Operating Regimes

    Energy Technology Data Exchange (ETDEWEB)

    L. Dorf; V. Semenov; Y. Raitses; N.J. Fisch

    2002-04-09

    A quasi one-dimensional (1-D) steady-state model of the Hall thruster is presented. For the same discharge voltage two operating regimes are possible -- with and without the anode sheath. For given mass flow rate, magnetic field profile and discharge voltage a unique solution can be constructed, assuming that the thruster operates in one of the regimes. However, we show that for a given temperature profile the applied discharge voltage uniquely determines the operating regime: for discharge voltages greater than a certain value, the sheath disappears. That result is obtained over a wide range of incoming neutral velocities, channel lengths and widths, and cathode plane locations. It is also shown that a good correlation between the quasi 1-D model and experimental results can be achieved by selecting an appropriate electron mobility and temperature profile.

  7. Regimes, Non-State Actors and the State System: A 'Structurational' Regime Model

    NARCIS (Netherlands)

    Arts, B.J.M.

    2000-01-01

    Regime analysis has become a popular approach in International Relations theory and in international policy studies. However, current regime models exhibit some shortcomings with regard to (1) addressing non-state actors, and in particular nongovernmental organizations (NGOs), (2) the balancing of a

  8. Causas estruturais e consequências dos regimes internacionais: regimes como variáveis intervenientes

    Directory of Open Access Journals (Sweden)

    Stephen D. Krasner

    2012-06-01

    Full Text Available Os regimes internacionais são definidos como princípios, normas, regras e procedimentos de tomada de decisões ao redor dos quais as expectativas dos atores convergem em uma dada área-tema. Como ponto de partida, os regimes são conceituados como variáveis intervenientes, estando entre fatores causais básicos e os resultados e comportamentos relacionados. Há três visões a respeito da importância dos regimes: as orientações estruturais convencionais desvalorizam os regimes como sendo, na melhor das hipóteses, ineficazes; as orientações grocianas vêem os regimes como componentes íntimos do sistema internacional; as perspectivas estruturalistas modificadas vêem os regimes como significativos somente em certas condições restritas. Para os argumentos grociano e estruturalista modificado - que concordam com a visão de que os regimes podem influenciar resultados e comportamentos - , o desenvolvimento de regimes é visto como uma função de cinco variáveis causais básicas: auto-interesse egoísta; poder político; normas e princípios difusos; usos e costumes; conhecimento.

  9. Supercurrent in the quantum Hall regime.

    Science.gov (United States)

    Amet, F; Ke, C T; Borzenets, I V; Wang, J; Watanabe, K; Taniguchi, T; Deacon, R S; Yamamoto, M; Bomze, Y; Tarucha, S; Finkelstein, G

    2016-05-20

    A promising route for creating topological states and excitations is to combine superconductivity and the quantum Hall (QH) effect. Despite this potential, signatures of superconductivity in the QH regime remain scarce, and a superconducting current through a QH weak link has been challenging to observe. We demonstrate the existence of a distinct supercurrent mechanism in encapsulated graphene samples contacted by superconducting electrodes, in magnetic fields as high as 2 tesla. The observation of a supercurrent in the QH regime marks an important step in the quest for exotic topological excitations, such as Majorana fermions and parafermions, which may find applications in fault-tolerant quantum computing. PMID:27199424

  10. Economic performance and North Korean regime legitimacy

    OpenAIRE

    Moore, Patrick J.

    2014-01-01

    This thesis examines the sources of legitimacy for the North Korean regime in an effort to explain what role, if any, economic performance has played in keeping the Kim family in power. This thesis provides a historical look at the development of the North Korean regime from the beginning under Kim Il-sung to the current generation of rule under Kim Jong-un. The core argument of the thesis is broken into two major time periods, with the economic downturn of the early 1990s serving as the divi...

  11. WELFARE REGIMES IN LATIN AMERICA AND CARIBBEAN

    Directory of Open Access Journals (Sweden)

    Melisa Campana-Alabarce

    2015-06-01

    Full Text Available This article provides a characterization of Latin American and Caribbean Welfare regimes in historiographical perspective. Firstly, it makes a review of the emergence conditions of Welfare States in Western Europe and its core features, with particular emphasis on its role as a method to regulate inequalities in industrial capitalism. Dialoguing with it, then stops in the specific configurations that welfare regimes have taken in Latin America during the course of the twentieth century. Finally, it provides a map of its contemporary features and the major challenges that the States of the region face in his capacity as right guarantors for the future.

  12. Light focusing in the Anderson Regime

    CERN Document Server

    Leonetti, Marco; Mafi, Arash; Conti, Claudio

    2014-01-01

    Anderson localization is a regime in which diffusion is inhibited and waves (also electromagnetic waves) get localized. Here we exploit adaptive optics to achieve focusing in disordered optical fibers in the Anderson regime. By wavefront shaping and optimization, we observe the generation of a propagation invariant beam, where light is trapped transversally by disorder, and show that Anderson localizations can be also excited by extended speckled beams. We demonstrate that disordered fibers allow a more efficient focusing action with respect to standard fibers in a way independent of their length, because of the propagation invariant features and cooperative action of transverse localizations.

  13. Synchronization regimes in conjugate coupled chaotic oscillators.

    Science.gov (United States)

    Karnatak, Rajat; Ramaswamy, Ram; Prasad, Awadhesh

    2009-09-01

    Nonlinear oscillators that are mutually coupled via dissimilar (or conjugate) variables display distinct regimes of synchronous behavior. In identical chaotic oscillators diffusively coupled in this manner, complete synchronization occurs only by chaos suppression when the coupled subsystems drive each other into a regime of periodic dynamics. Furthermore, the coupling does not vanish but acts as an "internal" drive. When the oscillators are mismatched, phase synchronization occurs, while in a master slave configuration, generalized synchrony results. These effects are demonstrated in a system of coupled chaotic Rossler oscillators.

  14. Supercurrent in the quantum Hall regime

    Science.gov (United States)

    Amet, F.; Ke, C. T.; Borzenets, I. V.; Wang, J.; Watanabe, K.; Taniguchi, T.; Deacon, R. S.; Yamamoto, M.; Bomze, Y.; Tarucha, S.; Finkelstein, G.

    2016-05-01

    A promising route for creating topological states and excitations is to combine superconductivity and the quantum Hall (QH) effect. Despite this potential, signatures of superconductivity in the QH regime remain scarce, and a superconducting current through a QH weak link has been challenging to observe. We demonstrate the existence of a distinct supercurrent mechanism in encapsulated graphene samples contacted by superconducting electrodes, in magnetic fields as high as 2 tesla. The observation of a supercurrent in the QH regime marks an important step in the quest for exotic topological excitations, such as Majorana fermions and parafermions, which may find applications in fault-tolerant quantum computing.

  15. Anomalous Hall effect in localization regime

    Science.gov (United States)

    Wu, Lin; Zhu, Kai; Yue, Di; Tian, Yuan; Jin, Xiaofeng

    2016-06-01

    The anomalous Hall effect in the ultrathin film regime is investigated in Fe(001)(1-3 nm) films epitaxial on MgO(001). The logarithmic localization correction to longitudinal resistivity and anomalous Hall resistivity are observed at low temperature. We identify that the coefficient of skew scattering has a reduction from metallic to localized regime, while the contribution of side jump has inconspicuous change except for a small drop below 10 K. Furthermore, we discover that the intrinsic anomalous Hall conductivity decreases with the reduction of thickness below 2 nm. Our results provide unambiguous experimental evidence to clarify the problem of localization correction to the anomalous Hall effect.

  16. The oil tax regime of Azerbaijan

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Gerard

    1998-07-01

    Azerbaijan has a long history in the oil business and a chance of a spectacular future. To understand why the oil tax regime evolved into its present form and how it is likely to develop, it is necessary to know something of the country's history and the commercial environment. Consequently the presentation begins by discussing these items. It then outlines the Production Sharing Agreement regime in Azerbaijan and then deals with the Kazakh and Georgian Tax Codes, as these are likely to be the basis of a new general tax law in Azerbaijan from 1999. The presentation includes comments on the New Draft Tax Code of 1998.

  17. Regimes of flow past a vortex generator

    DEFF Research Database (Denmark)

    Velte, Clara Marika; Okulov, V.L.; Naumov, I.V.

    2012-01-01

    particle image velocimetry (SPIV). Based on the obtained SPIV data, a map of the regimes of flow past the vortex generator has been constructed. One region with a developed stable multivortex system on this map reaches the vicinity of the optimum angle of attack of the vortex generator....

  18. In Search of the Chiral Regime

    CERN Document Server

    Beane, S R

    2004-01-01

    A critical appraisal is given of a recent analysis of the quark-mass and finite-size dependence of unquenched lattice QCD data for the nucleon mass. We use this forum to estimate the boundary of the chiral regime for nucleon properties.

  19. Optimal dividend distribution under Markov regime switching

    NARCIS (Netherlands)

    Z. Jiang; M. Pistorius

    2012-01-01

    We investigate the problem of optimal dividend distribution for a company in the presence of regime shifts. We consider a company whose cumulative net revenues evolve as a Brownian motion with positive drift that is modulated by a finite state Markov chain, and model the discount rate as a determini

  20. European welfare regimes: Political orientations versus poverty

    Directory of Open Access Journals (Sweden)

    Josifidis Kosta

    2011-01-01

    Full Text Available This inquiry analyzes how political orientations shape welfare states and labour market institutions when seeking to reduce poverty. In order to identify effects of these two key variables, we conduct a panel regression analysis that includes two poverty measures: poverty rates before and after social spending. This inquiry considers 14 EU countries, and in the period from 1995 to 2008, which are grouped according to welfare state regimes. We consider Social Democratic, Corporatist, Mediterranean and Liberal welfare state regimes. Panel regression results indicate that political orientation engenders no significant statistically measurable effects on poverty rates before social spending. Effects register, however, as significant when considering poverty rates after social spending. With respect to the first set of results, we advance two key explanations. First, we note a longer period of time is necessary in order to observe actual effects of political orientation on market generated poverty. Second, political parties with their respective programs do not register as influential enough to solve social problems related to income distribution when taken alone. Influences register as indirect and are expressed through changes in employment rates and social spending. The second set of results support the hypothesis that a selected political regime does indeed contribute to poverty reduction. In sum, political orientation and political regime does indeed affect poverty through welfare state institutions, as well as through labour market institutions.

  1. Estimation in autoregressive models with Markov regime

    OpenAIRE

    Ríos, Ricardo; Rodríguez, Luis

    2005-01-01

    In this paper we derive the consistency of the penalized likelihood method for the number state of the hidden Markov chain in autoregressive models with Markov regimen. Using a SAEM type algorithm to estimate the models parameters. We test the null hypothesis of hidden Markov Model against an autoregressive process with Markov regime.

  2. A Comparative Typology of Pension Regimes

    NARCIS (Netherlands)

    Arjan Soede; Cok Vrooman

    2008-01-01

    This report presents an empirical typology of pension regimes in the European Union, the US, Canada, Australia and Norway. The categorisation is based on 34 quantitative and qualitative characteristics of the mandatory parts of the pension systems in these countries. The empirical analysis shows tha

  3. Developmental Regimes in Africa synthesis report

    NARCIS (Netherlands)

    Booth, D.; Dietz, A.J.; Golooba-Mutebi, F.; Fuady, A.H.; Henley, D.; Kelsall, T.; Leliveld, A.H.M.; Donge, van J.K.

    2015-01-01

    Many African countries have experienced sustained economic growth, but few have achieved the type of structural change, driven by rising productivity, that has transformed mass living standards in parts of Asia. In the Developmental Regimes in Africa Synthesis Report, editor David Booth examines how

  4. Radiative effects of global MODIS cloud regimes

    Science.gov (United States)

    Oreopoulos, Lazaros; Cho, Nayeong; Lee, Dongmin; Kato, Seiji

    2016-03-01

    We update previously published Moderate Resolution Imaging Spectroradiometer (MODIS) global cloud regimes (CRs) using the latest MODIS cloud retrievals in the Collection 6 data set. We implement a slightly different derivation method, investigate the composition of the regimes, and then proceed to examine several aspects of CR radiative appearance with the aid of various radiative flux data sets. Our results clearly show that the CRs are radiatively distinct in terms of shortwave, longwave, and their combined (total) cloud radiative effect. We show that we can clearly distinguish regimes based on whether they radiatively cool or warm the atmosphere, and thanks to radiative heating profiles, to discern the vertical distribution of cooling and warming. Terra and Aqua comparisons provide information about the degree to which morning and afternoon occurrences of regimes affect the symmetry of CR radiative contribution. We examine how the radiative discrepancies among multiple irradiance data sets suffering from imperfect spatiotemporal matching depend on CR and whether they are therefore related to the complexity of cloud structure, its interpretation by different observational systems, and its subsequent representation in radiative transfer calculations.

  5. De facto and official exchange rate regimes in transition economies

    OpenAIRE

    von Hagen, Jürgen; Zhou, Jizhong

    2002-01-01

    This paper provides an empirical investigation on the discrepancies between official exchange rate regimes and de facto exchange rate policies in transition economies. Since official and de facto regime choices are not independent of each other, we adopt a bivariate probit model to describe the joint determination of the two regime choices. After finding the important determinants of both regime choices, we use a univariate probit model to describe the determination of regime discrepancies. W...

  6. The Effect of Market Regimes on Style Allocation

    OpenAIRE

    Ammann, Manuel; Verhofen, Michael

    2006-01-01

    We analyse time-varying risk premia and the implications for portfolio choice. Using Markov Chain Monte Carlo (MCMC) methods, we estimate a multivariate regime-switching model for the Carhart (1997) four factor model. We find two clearly separable Regimes with different mean returns, volatilities and correlations. In the High-Variance Regime, only value stocks deliver a good performance, whereas in the Low-Variance Regime, the market portfolio and momentum stocks promise high returns. Regime-...

  7. Regime shifts in the anthropocene: drivers, risks, and resilience.

    Science.gov (United States)

    Rocha, Juan Carlos; Peterson, Garry D; Biggs, Reinette

    2015-01-01

    Many ecosystems can experience regime shifts: surprising, large and persistent changes in the function and structure of ecosystems. Assessing whether continued global change will lead to further regime shifts, or has the potential to trigger cascading regime shifts has been a central question in global change policy. Addressing this issue has, however, been hampered by the focus of regime shift research on specific cases and types of regime shifts. To systematically assess the global risk of regime shifts we conducted a comparative analysis of 25 generic types of regime shifts across marine, terrestrial and polar systems; identifying their drivers, and impacts on ecosystem services. Our results show that the drivers of regime shifts are diverse and co-occur strongly, which suggests that continued global change can be expected to synchronously increase the risk of multiple regime shifts. Furthermore, many regime shift drivers are related to climate change and food production, whose links to the continued expansion of human activities makes them difficult to limit. Because many regime shifts can amplify the drivers of other regime shifts, continued global change can also be expected to increase the risk of cascading regime shifts. Nevertheless, the variety of scales at which regime shift drivers operate provides opportunities for reducing the risk of many types of regime shifts by addressing local or regional drivers, even in the absence of rapid reduction of global drivers. PMID:26267896

  8. Recent Activities on Global Nuclear Safety Regime

    International Nuclear Information System (INIS)

    Recently, rapid progress on the globalization of the nuclear safety issues is being made in IAEA (International Atomic Energy Agency) and its member states. With the globalization, the need for international cooperation among international bodies and member states continues to grow for resolving these universal nuclear safety issues. Furthermore, the importance of strengthening the global nuclear safety regime is emphasized through various means, such as efforts in application of IAEA safety standards to all nuclear installations in the world and in strengthening the code of conduct and the convention on nuclear safety. In this regards, it is important for us to keep up with the activities related with the global nuclear safety regime as an IAEA member state and a leading country in nuclear safety regulation

  9. Online recognition of the multiphase flow regime

    Institute of Scientific and Technical Information of China (English)

    BAI BoFeng; ZHANG ShaoJun; ZHAO Liang; ZHANG XiMin; GUO LieJin

    2008-01-01

    The key reasons that the present method cannot be used to solve the industrial multi-phase flow pattern recognition are clarified firstly. The prerequisite to realize the online recognition is proposed and recognition rules for partial flow pattern are obtained based on the massive experimental data. The standard templates for every flow regime feature are calculated with self-organization cluster algorithm. The multi-sensor data fusion method is proposed to realize the online recognition of multiphase flow regime with the pressure and differential pressure signals, which overcomes the severe influence of fluid flow velocity and the oil fraction on the recognition. The online recognition method is tested in the practice, which has less than 10 percent measurement error. The method takes advantages of high confidence, good fault tolerance and less requirement of single sensor performance.

  10. Online recognition of the multiphase flow regime

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The key reasons that the present method cannot be used to solve the industrial multi- phase flow pattern recognition are clarified firstly. The prerequisite to realize the online recognition is proposed and recognition rules for partial flow pattern are obtained based on the massive experimental data. The standard templates for every flow regime feature are calculated with self-organization cluster algorithm. The multi-sensor data fusion method is proposed to realize the online recognition of multiphase flow regime with the pressure and differential pressure signals, which overcomes the severe influence of fluid flow velocity and the oil fraction on the recognition. The online recognition method is tested in the practice, which has less than 10 percent measurement error. The method takes advantages of high confidence, good fault tolerance and less requirement of single sensor performance.

  11. Regimes de espaço

    Directory of Open Access Journals (Sweden)

    Eric Landowski

    2015-06-01

    Full Text Available Space Regimes - Based on a general model of interaction, the present analysis attempts to account for the diversity of the ways space may be apprehended in lived experience. It leads to the definition of four configurations that correspond to as many regimes of relation with the environing world. The conventional space of the circulation of values takes the archetypical shape of the net (incarnated today by Internet. The operational space is that of our dealing with objects within a material environment seen as a tissue of stable and intelligible relations. The experienced space of bodies’ movement, to which one may give as an emblem the spiral, expresses the dynamics of sensitive relationships between the self and the other. The existential space is that of our presence in a universe without boundaries, which no one can properly represent oneself but that nonetheless haunts art and thought: its figure is the abyss.

  12. Deuteron structure in the deep inelastic regime

    CERN Document Server

    Canal, C A Garcìa; Vento, V

    2016-01-01

    We study nuclear effects on the deuteron in the deep inelastic regime using the newest available data analyzing their $Q^2$ dependence. We conclude that precise EMC ratios for large $Q^2$ (> 30, GeV$^2$) cannot be obtained without considering these nuclear effects. For this purpose we use a scheme which parametrizes these effects in a simple manner and compare our results with other recent proposals.

  13. The Forex Regime and EMU Expansion

    OpenAIRE

    Foreest, P.W.; de Vries, Casper

    2002-01-01

    This paper provides evidence that the choice of the foreign exchange regime is not of first order importance for achieving high output growth. It is argued that due to the forward looking nature of the foreign exchange market, exchange rate stability hinges on the current and anticipated coherency of monetary and fiscal policies. We demonstrate this empirically on a panel including potential EMU accession countries. By means of rank regression analysis we uncover the partial links across the ...

  14. Dynamic Regime of Ignition of Solid Propellant

    Directory of Open Access Journals (Sweden)

    Zolotorev Nikolay

    2016-01-01

    Full Text Available This article presents a dynamic regime of exposure of the radiant flux on the sample of gun-cotton. Obtained time the ignition of gun-cotton in the heating conditions of increasing heat flux in the range from 0.2 W/cm2 to 22 W/cm2. A comparison of the delay times of the ignition when heated variable and constant heat flux.

  15. Exchange Rate Regimes and International Business Cycles

    OpenAIRE

    Theptida Sopraseuth

    2003-01-01

    This paper investigates the impact of exchange rate regimes on international business cycles and focuses on the consequences of membership to the European Monetary System. The volatility puzzle uncovered by Baxter and Stockman [1989, Journal of Monetary Economics 23, 377–401] after assessing the consequences of the Bretton Woods system turns out to be a robust stylized fact: real and nominal exchange rates display a higher volatility under floating rates while the variability of macroeconom...

  16. APPLICABLE LAW PRINCIPLES FOR MATRIMONIAL PROPERTY REGIMES

    OpenAIRE

    Andreea-Lorena CODREANU

    2014-01-01

    More and more often, marriages are concluded between people of different nationalities, which brings an extraneous dimension to the legal status and matrimonial property regime jurisdiction conflict. Many European states (among which Romania, through its new Civil Code) offer the advantage of clauses that could be used by any of the spouses, with regard to the applicable law. In case of divorce, consequences differ with the applicable law. Spouses who divorce and divide their assets based on ...

  17. Monetary policy regimes and the Nordic model

    OpenAIRE

    Schewe, Theo

    2015-01-01

    In many contexts, the Nordic countries are regarded as a natural bloc of nations that have common political, cultural and economic characteristics. Open to globalisation, the small Nordic countries are exposed to strong global competition and cyclical influences. Therefore, the basis of the model may be to combine collective risk sharing and openness to globalisation. Studies of the Nordic model do not focus on the question whether the monetary policy regime is a constitutive element of the m...

  18. Financing welfare regimes: mapping heterogeneous revenue structures

    OpenAIRE

    Gough, Ian; Abu-Sharkh, Miriam

    2011-01-01

    This article studies how the composition of public revenues in terms of sources (such as taxation, social insurance contributions, mineral rents, foreign aid) is associated with different welfare regimes and social policy outcomes. It is divided into two halves: a review of literature and research, and a cross-national data analysis. The first half reviews literature on the emergence of tax and revenue systems in the West, and on the relevance of these frameworks and findings to developing co...

  19. Snowpack regimes of the Western United States

    OpenAIRE

    Trujillo, Ernesto; Molotch, Noah P.

    2014-01-01

    Snow accumulation and melt patterns play a significant role in the water, energy, carbon, and nutrient cycles in the montane environments of the Western United States. Recent studies have illustrated that changes in the snow/rainfall apportionments and snow accumulation and melt patterns may occur as a consequence of changes in climate in the region. In order to understand how these changes may affect the snow regimes of the region, the current characteristics of the snow accumulation and mel...

  20. Tax incentive regimes: models and research methods

    OpenAIRE

    Sokolovska, Olena; Sokolovskyi, Dmytro

    2014-01-01

    Paper deals with problem of effectiveness of tax incentive regimes. Support of priority industries remains currently important for transition economies. At once, such countries more often than developed ones face the imperfection of tax incentive mechanisms. Notably, such problems are common to Ukrainian and Moldavian economies, where the legislative support or its implementation in the area of preferential taxation of innovative enterprises which contribute essentially to sustainable develop...

  1. Macro Regime and Economic Growth in China

    OpenAIRE

    Yuwen Dai

    2007-01-01

    In this paper, we investigate the relationship between Chinese macroeconomic policy and economic growth, and examine how the choice of macroeconomic regime affects economic performance in China. An open-economy model is developed for this purpose. It is a three-sector “almost small" open-economy macroeconomic model, with asset markets and forward-looking agents. This open-economy model is then adopted to analyse the implications of both domestic and external growth shocks to the Chinese econo...

  2. Exchange Rate Regimes, Location, and Specialization

    OpenAIRE

    Luca Antonio Ricci

    2006-01-01

    This paper investigates the effects of fixed versus flexible exchange rates on firms' location choices and on countries' specialization patterns. In a two-country, twodifferentiated-goods monetary model, uncertainty arises after wages are set and prices are optimally chosen. The paper shows that countries are more specialized under flexible than fixed rates, which indicates that the pattern of specialization is not uniquely defined by trade models but also depends on the exchange rate regime....

  3. British Columbia's new coalbed methane royalty regime

    International Nuclear Information System (INIS)

    The British Columbia Ministry of Energy and Mines is promoting the development of the coalbed methane (CBM) industry in the province in order to make CBM a viable and competitive investment option for industry. It is establishing a regulatory and fiscal regime for CBM development. Issues of concern regarding CBM development include water production, gas production rates, well numbers, and marginal economics. The features of the CBM royalty regime include a new producer cost of service allowance, the creation of a CBM royalty tax bank to collect excess PCOS allowances, and a royalty tax credit for wells drilled by the end of February, 2004. The marginal well adjustment factor threshold has been raised from 180 mcf per day to 600 mcf per day for CBM only. It was noted that royalties will probably not be payable for several years following the first commercial well because royalties are very depending on capital and operating costs, local infrastructure and price. Royalty regimes cannot save CBM from low gas prices, poor resources or economics. 2 figs

  4. Constructing an interdisciplinary flow regime recommendation

    Science.gov (United States)

    Bartholow, J.M.

    2010-01-01

    It is generally agreed that river rehabilitation most often relies on restoring a more natural flow regime, but credibly defining the desired regime can be problematic. I combined four distinct methods to develop and refine month-by-month and event-based flow recommendations to protect and partially restore the ecological integrity of the Cache la Poudre River through Fort Collins, Colorado. A statistical hydrologic approach was used to summarize the river's natural flow regime and set provisional monthly flow targets at levels that were historically exceeded 75% of the time. These preliminary monthly targets were supplemented using results from three Poudre-specific disciplinary studies. A substrate maintenance flow model was used to better define the high flows needed to flush accumulated sediment from the river's channel and help sustain the riparian zone in this snowmelt-dominated river. A hydraulic/habitat model and a water temperature model were both used to better define the minimum flows necessary to maintain a thriving cool water fishery. The result is a range of recommended monthly flows and daily flow guidance illustrating the advantage of combining a wide range of available disciplinary information, supplemented by judgment based on ecological principles and a general understanding of river ecosystems, in a highly altered, working river. ?? 2010 American Water Resources Association.

  5. The kinetic regime of the Vicsek model

    Science.gov (United States)

    Chepizhko, A. A.; Kulinskii, V. L.

    2009-12-01

    We consider the dynamics of the system of self-propelling particles modeled via the Vicsek algorithm in continuum time limit. It is shown that the alignment process for the velocities can be subdivided into two regimes: "fast" kinetic and "slow" hydrodynamic ones. In fast kinetic regime the alignment of the particle velocity to the local neighborhood takes place with characteristic relaxation time. So, that the bigger regions arise with the velocity alignment. These regions align their velocities thus giving rise to hydrodynamic regime of the dynamics. We propose the mean-field-like approach in which we take into account the correlations between density and velocity. The comparison of the theoretical predictions with the numerical simulations is given. The relation between Vicsek model in the zero velocity limit and the Kuramoto model is stated. The mean-field approach accounting for the dynamic change of the neighborhood is proposed. The nature of the discontinuity of the dependence of the order parameter in case of vectorial noise revealed in Gregorie and Chaite, Phys. Rev. Lett., 92, 025702 (2004) is discussed and the explanation of it is proposed.

  6. Autonomia e relevância dos regimes The autonomy and relevance of regimes

    Directory of Open Access Journals (Sweden)

    Gustavo Seignemartin de Carvalho

    2005-12-01

    Full Text Available Teorias institucionalistas na disciplina de relações internacionais usualmente definem regimes como um conjunto de normas e regras formais ou informais que permitem a convergência de expectativas ou a padronização do comportamento de seus participantes em uma determinada área de interesses com o objetivo de resolver problemas de coordenação que tenderiam a resultados não pareto-eficientes. Como estas definições baseadas meramente na "eficiência" dos regimes não parecem suficientes para explicar sua efetividade, o presente artigo propõe uma definição diferente para regimes: a de arranjos políticos que permitem a redistribuição dos ganhos da cooperação pelos participantes em uma determinada área de interesses em um contexto de interdependência. Regimes possuiriam efetividade pela sua autonomia e relevância, ou seja, por possuírem existência objetiva autônoma da de seus participantes e por influenciarem seu comportamento e expectativas de maneiras que não podem ser reduzidas à ação individual de nenhum deles. O artigo inicia-se com uma breve discussão sobre as dificuldades terminológicas associadas ao estudo de regimes e a definição dos conceitos de autonomia e relevância. Em seguida, classifica os diversos autores participantes do debate em duas perspectivas distintas, uma que nega (não-autonomistas e outra que atribui (autonomistas aos regimes autonomia e relevância, e faz uma breve análise dos autores e tradições mais significativos para o debate, aprofundando-se nos autonomistas e nos argumentos que reforçam a hipótese aqui apresentada. Ao final, o artigo propõe uma decomposição analítica dos regimes nos quatro elementos principais que lhes propiciam autonomia e relevância: normatividade, atores, especificidade da área de interesses e interdependência complexa com o contexto.Regimes are defined by institutionalist theories in the discipline of International Relations as formal or informal sets

  7. Refrigeration. Two-Phase Flow. Flow Regimes and Pressure Drop

    DEFF Research Database (Denmark)

    Knudsen, Hans-Jørgen Høgaard

    2002-01-01

    The note gives the basic definitions used in two-phase flow. Flow regimes and flow regimes map are introduced. The different contributions to the pressure drop are stated together with an imperical correlation from the litterature....

  8. Asymptotic Regime in N Random Interacting Species

    CERN Document Server

    Fiasconaro, A; Valenti, D

    2005-01-01

    The asymptotic regime of a complex ecosystem with N random interacting species and in the presence of an external multiplicative noise is analyzed. We find the role of the external noise on the long time probability distribution of the i_th density species, the extinction of species and the local field acting on the i_th population. We analyze in detail the transient dynamics of this field and the cavity field, which is the field acting on the i_th species when this is absent. We find that the presence or the absence of some population give different asymptotic distributions of these fields.

  9. REVIEW OF REGIME THEORY OF ALLUVIAL CHANNELS

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    One of the most important problems in river engineering is to determine a stable cross section geomenry and slope for an alluvial channel. This has been the subject of considerable research for about a century and continues to be of great practical interest. Lgnoring plan geometry, an alluvi-al channel can adjust its slope, depth and width, to develop a dynamic stable condition in which it can transport a certain a-mount of water and sediment. The brief history of regime the-ory and its new development are reviewed in this paper.

  10. Muscle's Motion in an Overdamped Regime

    Institute of Scientific and Technical Information of China (English)

    AI Bao-Quan; WANG Xian-Ju; LIU Liang-Gang; M. Nakano; H. Matsuura

    2002-01-01

    Based on the stochastic inclined rods model proposed by H. Matsuura et al., we study the motion of actin myosin system in an overdamped regime. Our model is composed ofan inclined spring (rod), a myosin head and a myosin filament. The results of calculation show that the modelcan convert the random motion to one-directional motion, and the myosin head works as a resonator of random noise, which absorbs the energy through a stochastic resonance. The results show that the inclined rod and the intermolecular potential are very important for the system to move.

  11. Autoritarismus in Peru : das Fujimori-Regime

    OpenAIRE

    Crabtree, John

    2007-01-01

    The ten-years presidency of Alberto Fujimori in Peru is a classic example of the sort of hybrid democracy that emerged in various Latin American countries in the 1990s, combining a mixture of democratic and clearly non-democratic elements. Fujimori was one of the more autocratic Latin American leaders of the 1990s, he is being the only regime formally to break with pre-existing constitutional rules. Closely tied to the military and intelligence apparatus, his government involved a concentrati...

  12. Efficiency of Rectification: Reversible vs. Irreversible Regimes

    Science.gov (United States)

    Sokolov, I. M.

    2002-11-01

    Both man-made locomotive devices and molecular motors use gears to transform a reciprocating motion into a directed one. One of the most common gears is a rectifier, a mechanically irreversible appliance. The maximal energetic efficiency of an isothermic gear is bounded by unity, as a consequence of the Second Law. However, approaching this ideal efficiency does not imply approaching reversibility. We discuss what properties of a rectifier mostly influence the transduction efficiency and show that an appliance which locks under backward force is just the one which can approach the ideal efficiency either in the reversible or in the irreversible regime.

  13. The Tributary Regime in the oil sector

    International Nuclear Information System (INIS)

    The tributary regime of the oil sector, is framed by the fiscal crisis that the country, maxim if one keeps in mind the importance of the fiscal revenues originated in the exploitation of these resources in Colombia, so much for the tribute coming from the foreign investment of the sector, like for the utilities generated by ECOPETROL and its impact in the public finances. However in front of this focus, the strategic importance of maintaining the investment in hydrocarbons and the paper that the fiscal politics and the tributary politics for the sector should play in the future and they constitute the government's key pieces

  14. Random nanolasing in the Anderson localized regime

    DEFF Research Database (Denmark)

    Liu, Jin; Garcia, P. D.; Ek, Sara;

    2014-01-01

    multiple scattering. The applicability of random lasers has been limited due to multidirectional emission, lack of tunability, and strong mode competition with chaotic fluctuations due to a weak mode confinement. The regime of Anderson localization of light has been proposed for obtaining stable multimode...... random lasing, and initial work concerned macroscopic one-dimensional layered media. Here, we demonstrate on-chip random nanolasers where the cavity feedback is provided by the intrinsic disorder. The strong confinement achieved by Anderson localization reduces the spatial overlap between lasing modes...

  15. Asian Aspirations for Climate Regime Beyond 2012

    International Nuclear Information System (INIS)

    This report is based on the second round of 'The Asia-Pacific Consultations on Climate Regime Beyond 2012' in 2006 to further advance the frank exchange of opinions of policy makers, academics, and the private sector on specific issues of high priority to the region. These include: energy security and development, Clean Development Mechanism (CDM), technology development and transfer, and adaptation. This report presents a summary of what has been learnt through the current consultations, interviews, and questionnaire surveys with policy makers and climate policy researchers across the region

  16. Langmuir wave filamentation in the kinetic regime

    CERN Document Server

    Silantyev, Denis A; Rose, Harvey A

    2016-01-01

    Nonlinear Langmuir wave in the kinetic regime $k\\lambda_D\\gtrsim0.2$ has a transverse instability, where $k$ is the wavenumber and $\\lambda_D$ is the Debye length. The nonlinear stage of that instability development leads to the filamentation of Langmuir waves. Here we study the linear stage of transverse instability of both Bernstein-Greene-Kruskal (BGK) modes and dynamically prepared BGK-like initial conditions to find the same instability growth rate suggesting the universal mechanism for the kinetic saturation of stimulated Raman scatter in laser-plasma interaction experiments. Multidimensional Vlasov simulations results are compared to the theoretical predictions.

  17. Reconfigurable photoinduced metamaterials in the microwave regime

    CERN Document Server

    Rizza, Carlo; De Paulis, Francesco; Palange, Elia; Orlandi, Antonio; Columbo, Lorenzo; Prati, Franco

    2014-01-01

    We investigate optically reconfigurable dielectric metamaterials at gigahertz frequencies. More precisely, we study the microwave response of a subwavelength grating optically imprinted into a semiconductor slab. In the homogenized regime, we analytically evaluate the ordinary and extraordinary component of the effective permittivity tensor by taking into account the photo-carrier dynamics described by the ambipolar diffusion equation. We analyze the impact of semiconductor parameters on the gigahertz metamaterial response which turns out to be highly reconfigurable by varying the photogenerated grating and which can show a marked anisotropic behavior.

  18. The design of environmental regimes: Social construction, contextuality, and improvisation

    OpenAIRE

    Lejano

    2006-01-01

    While much of the literature on environmental regimes has focused on effectiveness, this article takes a new look at a lesser-studied topic, the evolution of regime design. Understanding how regimes differ in design, and how various factors and processes shape such design, is important if we are to more carefully craft these regimes. We should also pay close attention to the formative role of social construction and context. Focusing on transboundary marine programs, we see that their designs...

  19. Low-frequency regime transitions and predictability of regimes in a barotropic model

    CERN Document Server

    Nadiga, B T

    2016-01-01

    Predictability of flow is examined in a barotropic vorticity model that admits low frequency regime transitions between zonal and dipolar states. Such transitions in the model were first studied by Bouchet and Simonnet (2009) and are reminiscent of regime change phenomena in the weather and climate systems wherein extreme and abrupt qualitative changes occur, seemingly randomly, after long periods of apparent stability. Mechanisms underlying regime transitions in the model are not well understood yet. From the point of view of atmospheric and oceanic dynamics, a novel aspect of the model is the lack of any source of background gradient of potential-vorticity such as topography or planetary gradient of rotation rate (e.g., as in Charney & DeVore '79). We consider perturbations that are embedded onto the system's chaotic attractor under the full nonlinear dynamics as bred vectors---nonlinear generalizations of the leading (backward) Lyapunov vector. We find that ensemble predictions that use bred vector per...

  20. Hard and Soft Excitation Regimes of Kerr Frequency Combs

    CERN Document Server

    Matsko, Andrey B; Ilchenko, Vladimir S; Seidel, David; Maleki, Lute

    2011-01-01

    We theoretically study the stability conditions and excitation regimes of hyper-parametric oscillation and Kerr frequency comb generation in continuously pumped nonlinear optical resonators possessing anomalous group velocity dispersion. We show that both hard and soft excitation regimes are possible in the resonators. Selection between the regimes is achieved via change in the parameters of the pumping light.

  1. Level-ARCH Short Rate Models with Regime Switching

    DEFF Research Database (Denmark)

    Christiansen, Charlotte

    This paper introduces regime switching volatility into level- ARCH models for the short rates of the US, the UK, and Germany. Once regime switching and level effects are included there are no gains from including ARCH effects. It is of secondary importance exactly how the regime switching...

  2. Change of secondary water regime of Paks NPP. Change of secondary water regime at Unit 2

    International Nuclear Information System (INIS)

    The installation of high pH water regime during the 17th cycle of Unit 2 aimed to decrease the amount of transportation inlet of erosion-corrosion products (magnitude) in feedwater to SGs. The resolution of OAH-NBI permitting the installation ordained to make an evaluation of the process. The main conclusions and results are discussed. The high pH water regime proved to be adequate in the case of Unit 2 as well, similarly to Units 3, 4 and 1. (R.P.)

  3. The Asymptotic Regime of High Density QCD

    CERN Document Server

    Gay-Ducati, M B

    2000-01-01

    We discuss the distinct approaches for high density QCD (hdQCD) in the asymptotic regime of large values of parton density. We derive the AGL equation for running coupling constant and obtain the asymptotic solution, demonstrating that the property of partial saturation of the solution of the AGL equation is not modified by the running of the coupling constant. We show that in this kinematical regime, the solution of the AGL equation coincides with the solution of an evolution equation, obtained recently using the McLerran-Venugopalan approach. Using the asymptotic behavior of the gluon distribution we calculate the $F_2$ structure function assuming first that the leading twist relation between these two quantities is valid and second that this relation is modified by the higher twist terms associated to the unitarity corrections. In the first case we obtain that the corresponding $F_2$ structure function is linearly proportional to $ln s$, which agrees with the results obtained recently by Kovchegov using a ...

  4. Dynamic regimes of random fuzzy logic networks

    Science.gov (United States)

    Wittmann, Dominik M.; Theis, Fabian J.

    2011-01-01

    Random multistate networks, generalizations of the Boolean Kauffman networks, are generic models for complex systems of interacting agents. Depending on their mean connectivity, these networks exhibit ordered as well as chaotic behavior with a critical boundary separating both regimes. Typically, the nodes of these networks are assigned single discrete states. Here, we describe nodes by fuzzy numbers, i.e. vectors of degree-of-membership (DOM) functions specifying the degree to which the nodes are in each of their discrete states. This allows our models to deal with imprecision and uncertainties. Compatible update rules are constructed by expressing the update rules of the multistate network in terms of Boolean operators and generalizing them to fuzzy logic (FL) operators. The standard choice for these generalizations is the Gödel FL, where AND and OR are replaced by the minimum and maximum of two DOMs, respectively. In mean-field approximations we are able to analytically describe the percolation and asymptotic distribution of DOMs in random Gödel FL networks. This allows us to characterize the different dynamic regimes of random multistate networks in terms of FL. In a low-dimensional example, we provide explicit computations and validate our mean-field results by showing that they agree well with network simulations.

  5. Variety of synchronous regimes in neuronal ensembles

    Science.gov (United States)

    Komarov, M. A.; Osipov, G. V.; Suykens, J. A. K.

    2008-09-01

    We consider a Hodgkin-Huxley-type model of oscillatory activity in neurons of the snail Helix pomatia. This model has a distinctive feature: It demonstrates multistability in oscillatory and silent modes that is typical for the thalamocortical neurons. A single neuron cell can demonstrate a variety of oscillatory activity: Regular and chaotic spiking and bursting behavior. We study collective phenomena in small and large arrays of nonidentical cells coupled by models of electrical and chemical synapses. Two single elements coupled by electrical coupling show different types of synchronous behavior, in particular in-phase and antiphase synchronous regimes. In an ensemble of three inhibitory synaptically coupled elements, the phenomenon of sequential synchronous dynamics is observed. We study the synchronization phenomena in the chain of nonidentical neurons at different oscillatory behavior coupled with electrical and chemical synapses. Various regimes of phase synchronization are observed: (i) Synchronous regular and chaotic spiking; (ii) synchronous regular and chaotic bursting; and (iii) synchronous regular and chaotic bursting with different numbers of spikes inside the bursts. We detect and study the effect of collective synchronous burst generation due to the cluster formation and the oscillatory death.

  6. Regimes of piezoelectric transformer operation II

    International Nuclear Information System (INIS)

    Piezoelectric transformers (PTs) have some attractive features for using them in power supply systems such as high efficiency and high power density, a high level of isolation between primary and secondary sides, a flat design which is well suited for a lot of applications and a low level of electromagnetic noise, just to name a few. For any application it is of utmost importance to know the behavior of a piezoelectric transformer under different conditions, which we call regimes of transformer operation. Based on this knowledge, criteria for safe operation of the PT in the power supply system and hence for the whole system as well can be derived. After having introduced the regimes of piezoelectric transformer operation in a first article on this topic in 2006 [1], in this paper we will present the derivation of important parameters based on measurements by way of an example of a symmetric PT. These measurements facilitate the basic understanding for choosing the appropriate transformer parameters necessary for its optimal as well as safe and controlled operation in power supply systems

  7. Characterizing multistationarity regimes in biochemical reaction networks.

    Directory of Open Access Journals (Sweden)

    Irene Otero-Muras

    Full Text Available Switch like responses appear as common strategies in the regulation of cellular systems. Here we present a method to characterize bistable regimes in biochemical reaction networks that can be of use to both direct and reverse engineering of biological switches. In the design of a synthetic biological switch, it is important to study the capability for bistability of the underlying biochemical network structure. Chemical Reaction Network Theory (CRNT may help at this level to decide whether a given network has the capacity for multiple positive equilibria, based on their structural properties. However, in order to build a working switch, we also need to ensure that the bistability property is robust, by studying the conditions leading to the existence of two different steady states. In the reverse engineering of biological switches, knowledge collected about the bistable regimes of the underlying potential model structures can contribute at the model identification stage to a drastic reduction of the feasible region in the parameter space of search. In this work, we make use and extend previous results of the CRNT, aiming not only to discriminate whether a biochemical reaction network can exhibit multiple steady states, but also to determine the regions within the whole space of parameters capable of producing multistationarity. To that purpose we present and justify a condition on the parameters of biochemical networks for the appearance of multistationarity, and propose an efficient and reliable computational method to check its satisfaction through the parameter space.

  8. Elastic regimes of subisostatic athermal fiber networks.

    Science.gov (United States)

    Licup, A J; Sharma, A; MacKintosh, F C

    2016-01-01

    Athermal models of disordered fibrous networks are highly useful for studying the mechanics of elastic networks composed of stiff biopolymers. The underlying network architecture is a key aspect that can affect the elastic properties of these systems, which include rich linear and nonlinear elasticity. Existing computational approaches have focused on both lattice-based and off-lattice networks obtained from the random placement of rods. It is not obvious, a priori, whether the two architectures have fundamentally similar or different mechanics. If they are different, it is not clear which of these represents a better model for biological networks. Here, we show that both approaches are essentially equivalent for the same network connectivity, provided the networks are subisostatic with respect to central force interactions. Moreover, for a given subisostatic connectivity, we even find that lattice-based networks in both two and three dimensions exhibit nearly identical nonlinear elastic response. We provide a description of the linear mechanics for both architectures in terms of a scaling function. We also show that the nonlinear regime is dominated by fiber bending and that stiffening originates from the stabilization of subisostatic networks by stress. We propose a generalized relation for this regime in terms of the self-generated normal stresses that develop under deformation. Different network architectures have different susceptibilities to the normal stress but essentially exhibit the same nonlinear mechanics. Such a stiffening mechanism has been shown to successfully capture the nonlinear mechanics of collagen networks. PMID:26871101

  9. Essence and Prospect of International Export Control Regimes

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    @@ International export control regimes are referring to the regimes and systems concerning limitation of export and transference of military-use and dual-use items and related parts as well as technologies. In the past couple of years, the control regimes have shown a strengthening posture. In addition, a new global export control regime is brewing. Hence export control has caught the attention of the international community, and particularly of the circles of armament control and commerce. The author would like to make some analyses of the posture and then try to predict the trend of international export control regimes.

  10. Quaternary Faults and Stress Regime of Venezuela

    Directory of Open Access Journals (Sweden)

    F.A. Audemard M.

    2006-12-01

    Full Text Available Spatial configuration of Quaternary active tectonic features along the southern Caribbean plate boundary suggests that the region is subject to a compressive strike-slip (transpressional senso lato regime, characterized by a NNW-SSE maximum horizontal stress (sH=s1 and/or an ENE-WSW minimum (s h=s3 or s2 horizontal stress. Stress inversion applied to fault-plane kinematic indicators measured essentially in Plio-Quaternary sedimentary rocks confirms this tectonic regime. Accordingly, this stress regime is responsible for the Quaternary activity and kinematics of six sets of brittle features along northern Venezuela (from Colombia in the west to Trinidad in the east: (1 east-west rightlateral faults, (2 NW right-lateral faults -acting as synthetic Riedel shears-, (3 ENE to east-west dextral faults -P shears-, (4 NNW normal faults, (5 almost north-south left-lateral faults -antithetic Riedel shears- and (6 mostly subsurface ENE reverse faults associated with folding of the same orientation. Brittle deformation conforms to the simple shear model, although not all the deformation can be accounted for it since strain partitioning is also taking place because regional folding and thrusting are due to the normal-to-structure component of the relative slip vector between the Caribbean and South America plates. On the other hand, the maximum horizontal stress in western Venezuela, particularly in the Maracaibo block and south of the Oca-Ancón fault, progressively turns counter-clockwise to become more east-west oriented, producing left- and right-lateral slip along the north-south striking and NE-SW striking faults, respectively. The orientation and spatial variation of this regional stress field in western Venezuela results from the superposition of the two major neighboring interplate maximum horizontal stress orientations (sH: roughly east-west trending stress across the Nazca-South America type-B subduction along the pacific coast of Colombia and NNW

  11. Institutional design and regime effectiveness in transboundary river management – the Elbe water quality regime

    Directory of Open Access Journals (Sweden)

    I. Dombrowsky

    2007-06-01

    Full Text Available The literature on transboundary river management suggests that institutions play an important role in bringing cooperation about. However, the knowledge on how they should be designed in order to do so remains limited. One way to learn more about adequate institutional design is to assess the effectiveness of existing regimes, and to trace the causal relationships leading to the respective outcomes. In order to gain further insights into the relationship of institutional design and regime effectiveness, this paper presents a study on the water quality regime of the International Commission for the Protection of the Elbe (ICPE. The analysis is based on a review of pertinent documents and ten qualitative interviews with Czech and German Commission members and NGO representatives. Particular emphasis has been put on determining the ICPE's specific contribution and the no-regime counterfactual as well as on the perceived expedience of the institutional arrangements. The study shows that overall due to external as well as internal institutional factors the ICPE proved relatively successful, and as such it also provides insights into how institutions matter: The commission served as platform for joint problem solving by identifying priorities for action. These international obligations increased the power of national administrations and their access to funds. At the same time, the Commission's reporting to the public served as an enforcement mechanism. However, the ICPE's contribution towards achieving the various goals varied significantly between the different areas of activity. It was high where the main responsibility for action was with the public authorities, such as in the area of wastewater treatment and the establishment of an international alarm plan and model. It was practically non existent in the reduction of non-point pollution from agriculture, where the success depended on the behavior of individual private actors (farmers. From a

  12. Two regimes of forced turbulent convection

    CERN Document Server

    Eidelman, A; Kleeorin, N; Rogachevskii, I; Sapir-Katiraie, I

    2009-01-01

    We study experimentally a forced turbulent convection in the Rayleigh-B\\'{e}nard apparatus with an additional source of turbulence produced by the two oscillating grids located nearby the side walls of the chamber. Two different regimes have been observed in the forced turbulent convection. When the frequency of the grid oscillations f>2 Hz, the large-scale circulation (LSC) is totally destroyed, and the destruction of the LSC is accompanied by a strong change of the mean temperature distribution. For the very low frequency the thermal structure inside the LSC is inhomogeneous and anisotropic. The hot thermal plumes accumulate at one side of LSC, and cold plumes concentrate at the opposite side of LSC. The mean temperature gradient in the horizontal direction inside the LSC is significantly larger than in the vertical direction. For the high frequency (f > 10 Hz), LSC has not been observed and the mean temperature gradient in the central flow region in the vertical direction, \

  13. The Great Lakes' regional climate regimes

    Science.gov (United States)

    Sugiyama, Noriyuki

    For the last couple of decades, the Great Lakes have undergone rapid surface warming. In particular, the magnitude of the summer surface-warming trends of the Great Lakes have been much greater than those of surrounding land (Austin and Colman, 2007). Among the Great Lakes, the deepest Lake Superior exhibited the strongest warming trend in its annual, as well as summer surface water temperature. We find that many aspects of this behavior can be explained in terms of the tendency of deep lakes to exhibit multiple regimes characterized, under the same seasonally varying forcing, by the warmer and colder seasonal cycles exhibiting different amounts of wintertime lake-ice cover and corresponding changes in the summertime lake-surface temperatures. In this thesis, we address the problem of the Great Lakes' warming using one-dimensional lake modeling to interpret diverse observations of the recent lake behavior. (Abstract shortened by ProQuest.).

  14. Regime shifts in models of dryland vegetation

    CERN Document Server

    Zelnik, Yuval R; Yizhaq, Hezi; Bel, Golan; Meron, Ehud

    2013-01-01

    Drylands are pattern-forming systems showing self-organized vegetation patchiness, multiplicity of stable states and fronts separating domains of alternative stable states. Pattern dynamics, induced by droughts or disturbances, can result in desertification shifts from patterned vegetation to bare soil. Pattern-formation theory suggests various scenarios for such dynamics; an abrupt global shift involving a fast collapse to bare soil, a gradual global shift involving the expansion and coalescence of bare-soil domains, and an incipient shift to a hybrid state consisting of stationary bare-soil domains in an otherwise periodic pattern. Using models of dryland vegetation we address the question which of these scenarios can be realized. We found that the models can be split into two groups: models that exhibit multiplicity of periodic-pattern and bare-soil states, and models that exhibit, in addition, multiplicity of hybrid states. Furthermore, in all models we could not identify parameter regimes in which bare-s...

  15. Environment Flow Assessment with Flow Regime Transition

    Science.gov (United States)

    Su, J.; Ho, C. C.; Chang, L. C.

    2015-12-01

    To avoid worsen river and estuarine ecosystems cause by overusing water resources, environmental flows conservation is applied to reduce the impact of river environment. Environmental flows refer to water provided within a river, wetland or coastal zone to sustain ecosystems and benefits to human wellbeing. Environment flow assessment is now widely accepted that a naturally variable flow regime, rather than just a minimum low flow. In this study, we propose four methods, experience method, Tenant method, hydraulic method and habitat method to assess the environmental flow of base flow, flush flow and overbank flow with different discharge, frequency and occurrence period. Dahan River has been chosen as a case to demonstrate the assessment mechanism. The alternatives impact analysis of environment and human water used provides a reference for stakeholders when holding an environmental flow consultative meeting.

  16. Nonlinear regimes of forced magnetic reconnection

    Energy Technology Data Exchange (ETDEWEB)

    Vekstein, G., E-mail: g.vekstein@manchester.ac.uk [JBCA, School of Physics and Astronomy, University of Manchester, Manchester M13 9PL (United Kingdom); STEL, Nagoya University, Nagoya, Aichi 464-8601 (Japan); Kusano, K. [STEL, Nagoya University, Nagoya, Aichi 464-8601 (Japan)

    2015-09-15

    This letter presents a self-consistent description of nonlinear forced magnetic reconnection in Taylor's model of this process. If external boundary perturbation is strong enough, nonlinearity in the current sheet evolution becomes important before resistive effects come into play. This terminates the current sheet shrinking that takes place at the linear stage and brings about its nonlinear equilibrium with a finite thickness. Then, in theory, this equilibrium is destroyed by a finite plasma resistivity during the skin-time, and further reconnection proceeds in the Rutherford regime. However, realization of such a scenario is unlikely because of the plasmoid instability, which is fast enough to develop before the transition to the Rutherford phase occurs. The suggested analytical theory is entirely different from all previous studies and provides proper interpretation of the presently available numerical simulations of nonlinear forced magnetic reconnection.

  17. Different spreading regimes of spray-flames

    Science.gov (United States)

    Suard, Sylvain; Haldenwang, Pierre; Nicoli, Colette

    2004-05-01

    We present a minimal model of spray combustion to investigate a flame front propagating through a fuel-lean mixture of fuel vapor, droplets and air. The model relies on a main control parameter, Da, named the Damkoehler number, which allows us to take into account a large variety of fuel sprays. Numerical results reveal, as a function of Da, a wide range of spray-flame structures, including the classical gaseous premixed flame, a specific regime controlled by vaporisation, and a pulsating mode of propagation. The latter appears when the vaporisation is smaller than (or equal to) the reaction time, and it occurs even with a unit Lewis number. To cite this article: S. Suard et al., C. R. Mecanique 332 (2004).

  18. The role of the media in establishing international security regimes

    Directory of Open Access Journals (Sweden)

    Chanan Naveh

    2005-04-01

    Full Text Available This article focuses primarily on the media's impact on international security regimes. It explores the ways in which the media affect the lifecycles of international regimes, from the time they are first conceived of, through their establishment, consolidation and stabilization, up until their ultimate demise. Although this paper highlights the media's role in the evolution of security regimes, it is clear that, regardless of the regime in question, media play a role throughout the lifecycle of all international regimes, whatever their character. In order to analyze the relationships of the media with security regimes in general, and specifically their contribution to each stage in their development, the article utilizes methodologies from the field of communication studies. It examines the media's agenda, "news values" and various functions, and their ability to mobilize public support for the particular issue of the regime. To date, most studies have explored the interaction between media communication patterns and global developments at the state level, or in relation to the formulation of foreign policy, while largely ignoring the international dimension of the relationship. This article attempts to remedy this situation, and the relevant processes are analysed in a case study of the anti-Iraq international security regime. It should be noted that although the paper focuses on the specific anti-Iraqi regime, it is part of a more general Anti-Rogue actors regime which includes the war against global terrorism. The study of the development of the anti-Iraq press-security regime teaches us that during international crises the media mobilize and unanimously support the regime fighting the "bad guys." But, when the regime develops and enters disputed turfs and begins to lose its legitimacy, media support diminishes, and the media may even develop into an opposing force and may join the actors fighting against this regime. Moreover, the study of

  19. Fiscal Policy and Welfare under Different Exchange Rate Regimes

    DEFF Research Database (Denmark)

    Østrup, Finn

    , and secondbecause the government's inclination to expand government spending is affectedby inflation which depends on the exchange rate regime. At low rates of inflation,the government is inclined to set a higher level of government spending under afixed exchange rate regime than under a floating exchange rate...... regime in whichthe monetary authority optimises preferences which include an employment targetand an inflation target. As government spending affects the representativeindividual's utility, the choice of exchange rate regime has an impact on welfare.Keywords: exchange rate regimes; fiscal policy......The article analyses how government spending is determined under differentexchange rate regimes in the context of a small open economy. Assumingnominal wage contracts which last for one period and assuming a benevolentgovernment which determines government spending to optimise...

  20. Detection and Assessment of Ecosystem Regime Shifts from Fisher Information

    OpenAIRE

    B. Roy Frieden; Christopher W. Pawlowski; Heriberto Cabezas; Arunprakash T. Karunanithi

    2008-01-01

    Ecosystem regime shifts, which are long-term system reorganizations, have profound implications for sustainability. There is a great need for indicators of regime shifts, particularly methods that are applicable to data from real systems. We have developed a form of Fisher information that measures dynamic order in complex systems. Here we propose the use of Fisher information as a means of: (1) detecting dynamic regime shifts in ecosystems, and (2) assessing the quality of the shift in terms...

  1. Spacetime-noncommutativity regime of Loop Quantum Gravity

    OpenAIRE

    AMELINO-CAMELIA, Giovanni; da Silva, Malú Maira; Ronco, Michele; Cesarini, Lorenzo; Lecian, Orchidea Maria

    2016-01-01

    A recent study by Bojowald and Paily provided a path toward the identification of an effective quantum-spacetime picture of Loop Quantum Gravity, applicable in the "Minkowski regime", the regime where the large-scale (coarse-grained) spacetime metric is flat. A pivotal role in the analysis is played by Loop-Quantum-Gravity-based modifications to the hypersurface deformation algebra, which leave a trace in the Minkowski regime. We here show that the symmetry-algebra results reported by Bojowal...

  2. Apparel exportism in Kenya: international regimes, chain governance and upgrading

    OpenAIRE

    Kindiki, M. M.

    2011-01-01

    An important question in development is how far can the contemporary global context create industrial development opportunities for the South, particularly for Low Income Countries? In an important sense, this can only be answered in non-abstract terms, since the institutional conditions facing particular industries at particular times are highly specific. In this research, a configuration of four regimes- the structural regime on production and trade in apparel, the labour regime, the neo-st...

  3. Flow regimes in a trapped vortex cell

    Science.gov (United States)

    Lasagna, D.; Iuso, G.

    2016-03-01

    This paper presents results of an experimental investigation on the flow in a trapped vortex cell, embedded into a flat plate, and interacting with a zero-pressure-gradient boundary layer. The objective of the work is to describe the flow features and elucidate some of the governing physical mechanisms, in the light of recent investigations on flow separation control using vortex cells. Hot-wire velocity measurements of the shear layer bounding the cell and of the boundary layers upstream and downstream are reported, together with spectral and correlation analyses of wall-pressure fluctuation measurements. Smoke flow visualisations provide qualitative insight into some relevant features of the internal flow, namely a large-scale flow unsteadiness and possible mechanisms driving the rotation of the vortex core. Results are presented for two very different regimes: a low-Reynolds-number case where the incoming boundary layer is laminar and its momentum thickness is small compared to the cell opening, and a moderately high-Reynolds-number case, where the incoming boundary layer is turbulent and the ratio between the momentum thickness and the opening length is significantly larger than in the first case. Implications of the present findings to flow control applications of trapped vortex cells are also discussed.

  4. Scaling regimes in spherical shell rotating convection

    CERN Document Server

    Gastine, T; Aubert, J

    2016-01-01

    Rayleigh-B\\'enard convection in rotating spherical shells can be considered as a simplified analogue of many astrophysical and geophysical fluid flows. Here, we use three-dimensional direct numerical simulations to study this physical process. We construct a dataset of more than 200 numerical models that cover a broad parameter range with Ekman numbers spanning $3\\times 10^{-7} \\leq E \\leq 10^{-1}$, Rayleigh numbers within the range $10^3 < Ra < 2\\times 10^{10}$ and a Prandtl number unity. We investigate the scaling behaviours of both local (length scales, boundary layers) and global (Nusselt and Reynolds numbers) properties across various physical regimes from onset of rotating convection to weakly-rotating convection. Close to critical, the convective flow is dominated by a triple force balance between viscosity, Coriolis force and buoyancy. For larger supercriticalities, a subset of our numerical data approaches the asymptotic diffusivity-free scaling of rotating convection $Nu\\sim Ra^{3/2}E^{2}$ in ...

  5. Multimode optomechanical system in the quantum regime

    CERN Document Server

    Nielsen, William H P; Møller, Christoffer B; Polzik, Eugene S; Schliesser, Albert

    2016-01-01

    We realise a simple and robust optomechanical system with a multitude of long-lived ($Q>10^7$) mechanical modes in a phononic-bandgap shielded membrane resonator. An optical mode of a compact Fabry-Perot resonator detects these modes' motion with a measurement rate ($96~\\mathrm{kHz}$) that exceeds the mechanical decoherence rates already at moderate cryogenic temperatures ($10\\,\\mathrm{K}$). Reaching this quantum regime entails, i.~a., quantum measurement backaction exceeding thermal forces, and thus detectable optomechanical quantum correlations. In particular, we observe ponderomotive squeezing of the output light mediated by a multitude of mechanical resonator modes, with quantum noise suppression up to -2.4 dB (-3.6 dB if corrected for detection losses) and bandwidths $\\lesssim 90\\,\\mathrm{ kHz}$. The multi-mode nature of the employed membrane and Fabry-Perot resonators lends itself to hybrid entanglement schemes involving multiple electromagnetic, mechanical, and spin degrees of freedom.

  6. Global fishery prospects under contrasting management regimes.

    Science.gov (United States)

    Costello, Christopher; Ovando, Daniel; Clavelle, Tyler; Strauss, C Kent; Hilborn, Ray; Melnychuk, Michael C; Branch, Trevor A; Gaines, Steven D; Szuwalski, Cody S; Cabral, Reniel B; Rader, Douglas N; Leland, Amanda

    2016-05-01

    Data from 4,713 fisheries worldwide, representing 78% of global reported fish catch, are analyzed to estimate the status, trends, and benefits of alternative approaches to recovering depleted fisheries. For each fishery, we estimate current biological status and forecast the impacts of contrasting management regimes on catch, profit, and biomass of fish in the sea. We estimate unique recovery targets and trajectories for each fishery, calculate the year-by-year effects of alternative recovery approaches, and model how alternative institutional reforms affect recovery outcomes. Current status is highly heterogeneous-the median fishery is in poor health (overfished, with further overfishing occurring), although 32% of fisheries are in good biological, although not necessarily economic, condition. Our business-as-usual scenario projects further divergence and continued collapse for many of the world's fisheries. Applying sound management reforms to global fisheries in our dataset could generate annual increases exceeding 16 million metric tons (MMT) in catch, $53 billion in profit, and 619 MMT in biomass relative to business as usual. We also find that, with appropriate reforms, recovery can happen quickly, with the median fishery taking under 10 y to reach recovery targets. Our results show that commonsense reforms to fishery management would dramatically improve overall fish abundance while increasing food security and profits. PMID:27035953

  7. Crossing into the substellar regime in Praesepe

    CERN Document Server

    Chappelle, R J; Steele, I A; Dobbie, P D; Magazzù, A

    2005-01-01

    We present the results of a deep optical 2.6 square degree survey with near infrared follow-up measurements of the intermediate-aged Praesepe open cluster. The survey is complete to I=21.3, Z=20.5, corresponding to ~0.06 Solar Masses assuming a cluster age of 0.5 Gyrs. Using 3-5 pass-bands to constrain cluster membership, we identify 32 new low mass cluster members, at least 4 of which are likely to be substellar. We use the low mass census to trace the region where the sequence moves away from the NEXTGEN towards the Dusty regime at Teff = 2200K. In doing so, we identify four unresolved binaries, yielding a substellar binary fraction of ~30 percent. The binary fractions appear to decrease below 0.1 Solar Masses, in contrast to the rising fractions found in the Pleiades. We also identify a paucity of late M dwarfs, thought to be due to a steepening in the mass-luminosity relation at these spectral types, and compare the properties of this gap in the sequence to those observed in younger clusters. We note an o...

  8. On the ontological emergence from quantum regime

    Energy Technology Data Exchange (ETDEWEB)

    Luty, Damian [Adam Mickiewicz University, Poznan (Poland)

    2014-07-01

    There are several views on the relation between quantum physics and theory of relativity (especially General Relativity, GR). A popular perspective is this: GR with its macroscopic gravitational effects will turn out to be a limit of a more fundamental theory which should consider discrete physics and not deal with continuity (like theory of relativity). Thus, GR will emerge from a more basic theory, which should be quantum-like. One could call this an epistemic emergence view towards fundamental theories. The question is, given that scientific realism is valid: should emergence be a fundamental notion in our ontological view about the evolving, physical Universe? Is there an ontological emergence fully compatible with the notion of fundamentality? I argue that if we want to defend ontological emergence (from quantum to macroscopic regime) as something fundamental, we will arrive at the position of metaphysics of dispositions (and I argue, why this is undesirable), or conclude, that we cannot square fully fundamental ontology with the notion of emergence, and that we have to accept an ontological pluralism relativised to a certain scale. I defend the latter proposition, showing, that epistemic emergence doesn't entail (logically) ontological emergence.

  9. Regime shifts in a social-ecological system

    OpenAIRE

    Lade, Steven J.; Tavoni, Alessandro; Levin, Simon A.; Schlüter, Maja

    2013-01-01

    Ecological regime shifts are rarely purely ecological. Not only is the regime shift frequently triggered by human activity, but the responses of relevant actors to ecological dynamics are often crucial to the development and even existence of the regime shift. Here, we show that the dynamics of human behaviour in response to ecological changes can be crucial in determining the overall dynamics of the system. We find a social-ecological regime shift in a model of harvesters of a common-pool re...

  10. Institutional design and regime effectiveness in transboundary river management – the Elbe water quality regime

    Directory of Open Access Journals (Sweden)

    I. Dombrowsky

    2008-02-01

    Full Text Available The literature on transboundary river management suggests that institutions play an important role in bringing about cooperation. However, knowledge about how such institutions should be designed in order to do so remains limited. One way to learn more about adequate institutional design is to assess the effectiveness of existing regimes, and to trace the causal relationships that lead to the respective outcomes. In order to gain further insights into the relationship between institutional design and regime effectiveness, this paper presents a study on the water quality regime of the International Commission for the Protection of the Elbe (ICPE. The analysis is based on a review of pertinent documents and ten qualitative interviews with Czech and German Commission members and NGO representatives. Particular emphasis has been put on determining the ICPE's specific contribution and the no-regime counterfactual as well as on the perceived expediency of the institutional arrangements. The study shows overall that the countries were relatively successful in improving water quality in the Elbe basin. However, this outcome can only partly be attributed to the ICPE itself. Furthermore, the ICPE's contribution towards achieving the various goals varied significantly between the different areas of activity: it was relatively significant where the main responsibility for action lay with the public authorities, such as in the area of wastewater treatment and the establishment of an international alarm plan and model, but was practically non-existent in the reduction of non-point pollution from agriculture, where success depended on the behavior of individual private actors (farmers. The commission contributed towards problem solving by serving as a forum for the joint identification of priorities for action from a basin-wide perspective. The resulting international obligations increased the power of national water administrations and their access to funds

  11. Varieties of Economic Growth Regimes, Types of Macroeconomic Policies, and Policy Regime: A Post-Keynesian Analysis

    OpenAIRE

    Hiroshi Nishi

    2012-01-01

    This study explores the effects of macroeconomic policies on measures of macroeconomic performance such as growth and inflation by setting up a dynamic post-Keynesian model with government and central bank interventions. In doing so, this study reconsiders the arguments in favor of a policy regime. The model in this paper generates several varieties of economic growth regimes and inflation dynamics. The economic growth regimes are defined by the relationship between economic growth, the incom...

  12. CSDP: Seismology of continental thermal regime

    Energy Technology Data Exchange (ETDEWEB)

    Aki, K.

    1989-04-01

    This is a progress report for the past one year of research (year 2 of 5-year project) under the project titled CSDP: Seismology of Continental Thermal Regime'', in which we proposed to develop seismological interpretation theory and methods applicable to complex structures encountered in continental geothermal areas and apply them to several candidate sites for the Continental Scientific Drilling Project. During the past year, two Ph.D. thesis works were completed under the present project. One is a USC thesis on seismic wave propagation in anisotropic media with application to defining fractures in the earth. The other is a MIT thesis on seismic Q and velocity structure for the magma-hydrothermal system of the Valles Caldera, New Mexico. The P.I. co-organized the first International Workshop on Volcanic Seismology at Capri, Italy in October 1988, and presented the keynote paper on the state-of-art of volcanic seismology''. We presented another paper at the workshop on Assorted Seismic Signals from Kilauea Volcano, Hawaii. Another international meeting, namely, the Chapman Conference on seismic anisotropy in the earth's crust at Berkeley, California in May 1988, was co-organized by the co-P.I. (P.C.L), and we presented our work on seismic waves in heterogeneous and anisotropic media. Adding the publications and presentations made in the past year to the list for the preceding year, the following table lists 21 papers published, submitted or presented in the past two years of the present project. 65 refs., 334 figs., 1 tab.

  13. Dissipation regimes for short wind waves

    Science.gov (United States)

    Caulliez, Guillemette

    2013-02-01

    The dissipation processes affecting short wind waves of centimeter and decimeter scales are investigated experimentally in laboratory. The processes include damping due to molecular viscosity, generation of capillary waves, microbreaking, and breaking. The observations were made in a large wind wave tank for a wide range of fetches and winds, using a laser sheet and a high-resolution video camera. The work aims at constructing a comprehensive picture of dissipative processes in the short wind wave field, to find for which scales particular dissipative mechanism may become important. Four distinct regimes have been identified. For capillary-gravity wave fields, i.e., for dominant waves with scales below 4 cm, viscous damping is found to be the main dissipation mechanism. The gravity-capillary wave fields with dominant wavelength less than 10 cm usually exhibit a train of capillary ripples at the crest wavefront, but no wave breaking. For such waves, the main dissipation process is molecular viscosity occurring through nonlinear energy cascade toward high-frequency motions. Microscale breaking takes place for waves longer than 10 cm and manifests itself in a very localized surface disruption on the forward face of the crest. Such events generate turbulent motions in water and thus enhance wave dissipation. Plunging breaking, characterized by formation of a crest bulge, a microjet hitting the water surface and a splash-up, occurs for short gravity waves of wavelength exceeding 20 cm. Macroscale spilling breaking is also observed for longer waves at high winds. In both cases, the direct momentum transfer from breaking waves to the water flow contributes significantly to wave damping.

  14. The seismology of geothermal regimes. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Aki, K.

    1997-04-01

    The authors have been developing seismological interpretation theory and methods applicable to complex structures encountered in geothermal areas for a better understanding of the earth`s geothermal regimes. The questions the y have addressed in their research may be summarized as ``What is going on in the earth`s crust under tectonically active regions; what are the structures and processes responsible for such activities as earthquakes and volcanic eruptions; and how can one capture their essence effectively by means of seismological studies?`` First, the authors found clear evidence for localization of scattered seismic energy in the deep magmatic system of the volcano on the island of Reunion in the Indian Ocean. The seismic coda of local earthquakes show concentrated energy in the intrusive zones as late as 30 to 40 seconds after the origin time. This offers a very effective method for defining a zone of strong heterogeneity on a regional scale, complementary to the high resolution study using trapped modes as pursued in the past project. Secondly, the authors identified about 700 long-period events with various frequencies and durations from the data collected during the past 5 years which included three episodes of eruption. They are applying a finite-element method to the simplest event with the longest period and the shortest duration in order to find the location, geometry and physical properties of their source deterministically. The preliminary result described here suggests that their sources may be a horizontally lying magma-filled crack at a shallow depth under the summit area. In addition to the above work on the Reunion data, they have continued the theoretical and observational studies of attenuation and scattering of seismic waves.

  15. Antecedents of Teachers Fostering Effort within two different management regimes: An assessment-based accountability regime and regime without external pressure on results

    OpenAIRE

    Knut-Andreas Christophersen; Eyvind Elstad; Are Turmo

    2012-01-01

    This article focuses on the comparison of organizational antecedents of teachers' fostering of students' effort in two quite different accountability regimes: one management regime with an external-accountability system and one with no external accountability devices. The methodology involves cross-sectional surveys from two different management systems: (1) teachers working under assessment-based accountability (N = 236) and (2) folk–high school teachers who work without tests and examinatio...

  16. Antecedents of Teachers Fostering Effort within two different management regimes: An assessment-based accountability regime and regime without external pressure on results

    Directory of Open Access Journals (Sweden)

    Knut-Andreas Christophersen

    2012-12-01

    Full Text Available This article focuses on the comparison of organizational antecedents of teachers' fostering of students' effort in two quite different accountability regimes: one management regime with an external-accountability system and one with no external accountability devices. The methodology involves cross-sectional surveys from two different management systems: (1 teachers working under assessment-based accountability (N = 236 and (2 folk–high school teachers who work without tests and examinations and, thereby, without external accountability devices (N = 366. The purpose of the study is to estimate the path coefficients in structural equation modeling in the two regimes and compare the significance of relationships between concepts in the structural models. Through this comparison, inferences are drawn suggesting how accountability repercussions and other leadership organizational antecedents may influence teachers' fostering of students' efforts and how qualitative aspects among school professionals may influence the fostering of effort. Implications for practice and directions for future research are discussed.Christopherson, K, Elstad, E, & Turmo, A. (2012. Antecedents of teachers fostering effort within two different management regimes: an assessment-based accountability regime and regime without external pressure on results. International Journal of Education Policy and Leadership 7(6. Retrieved from www.ijepl.org.

  17. Transition to ballistic regime for heat transport in helium II

    Energy Technology Data Exchange (ETDEWEB)

    Sciacca, Michele, E-mail: michele.sciacca@unipa.it [Dipartimento Scienze Agrarie e Forestali, Università degli studi di Palermo, Viale delle Scienze, 90128 Palermo (Italy); Departament de Física, Universitat Autònoma de Barcelona, 08193 Bellaterra, Catalonia (Spain); Sellitto, Antonio, E-mail: ant.sellitto@gmail.com [Dipartimento di Matematica, Informatica ed Economia, Università della Basilicata, Campus Macchia Romana, 85100 Potenza (Italy); Jou, David, E-mail: david.jou@uab.cat [Departament de Física, Universitat Autònoma de Barcelona, 08193 Bellaterra, Catalonia (Spain); Institut d' Estudis Catalans, Carme 47, 08001 Barcelona, Catalonia (Spain)

    2014-07-04

    The size-dependent and flux-dependent effective thermal conductivity of narrow capillaries filled with superfluid helium is analyzed from a thermodynamic continuum perspective. The classical Landau evaluation of the effective thermal conductivity of quiescent superfluid, or the Gorter–Mellinck regime of turbulent superfluids, is extended to describe the transition to ballistic regime in narrow channels wherein the radius R is comparable to (or smaller than) the phonon mean-free path ℓ in superfluid helium. To do so, we start from an extended equation for the heat flux incorporating non-local terms, and take into consideration a heat slip flow along the walls of the tube. This leads from an effective thermal conductivity proportional to R{sup 2} (Landau regime) to another one proportional to Rℓ (ballistic regime). We consider two kinds of flows: along cylindrical pipes and along two infinite parallel plates. - Highlights: • Heat transport in counterflow helium in the ballistic regime. • The one-fluid model based on the Extended Thermodynamics is used. • The transition from the Landau regime to the ballistic regime. • The transition from quantum turbulence to ballistic regime.

  18. Consumption, investment and life insurance under different tax regimes

    DEFF Research Database (Denmark)

    Bruun, Kenneth

    2013-01-01

    , and compare tax effects on consumption/savings contributions, investment and purchase of life insurance under the regimes. The optimization problems have analytical solutions, which allow for easy comparison of tax effects under the different regimes. To substantiate the results we also present a numerical...

  19. Bargaining among Nations: Culture, History, and Perceptions in Regime Formation.

    Science.gov (United States)

    Lipschutz, Ronnie D.

    1991-01-01

    The formation of regimes (collective international schemes) for managing global problems depends on culture, history, and perceptions. The ways in which these elements affect bargaining among nations over issues of the global commons are discussed. Implications are reviewed for a regime to deal with atmospheric conditions and global warming. (SLD)

  20. Disciplinary Regimes of "Care" and Complementary Alternative Education

    Science.gov (United States)

    Thomson, Pat; Pennacchia, Jodie

    2016-01-01

    In schools, the notion of "care" is often synonymous with welfare and disciplinary regimes. Drawing on Foucault, and a study of alternative education (AE) across the UK, and looking in depth at two cases of complementary AE, we identify three types of disciplinary regimes at work in schools: (1) dominant performative reward and…

  1. Transition to ballistic regime for heat transport in helium II

    International Nuclear Information System (INIS)

    The size-dependent and flux-dependent effective thermal conductivity of narrow capillaries filled with superfluid helium is analyzed from a thermodynamic continuum perspective. The classical Landau evaluation of the effective thermal conductivity of quiescent superfluid, or the Gorter–Mellinck regime of turbulent superfluids, is extended to describe the transition to ballistic regime in narrow channels wherein the radius R is comparable to (or smaller than) the phonon mean-free path ℓ in superfluid helium. To do so, we start from an extended equation for the heat flux incorporating non-local terms, and take into consideration a heat slip flow along the walls of the tube. This leads from an effective thermal conductivity proportional to R2 (Landau regime) to another one proportional to Rℓ (ballistic regime). We consider two kinds of flows: along cylindrical pipes and along two infinite parallel plates. - Highlights: • Heat transport in counterflow helium in the ballistic regime. • The one-fluid model based on the Extended Thermodynamics is used. • The transition from the Landau regime to the ballistic regime. • The transition from quantum turbulence to ballistic regime

  2. States agree on stronger physical protection regime

    International Nuclear Information System (INIS)

    Full text: Delegates from 89 countries agreed on 8 July to fundamental changes that will substantially strengthen the Convention on the Physical Protection of Nuclear Material (CPPNM). IAEA Director General Mohamed ElBaradei welcomed the agreement in saying 'This new and stronger treaty is an important step towards greater nuclear security by combating, preventing, and ultimately punishing those who would engage in nuclear theft, sabotage or even terrorism. It demonstrates that there is indeed a global commitment to remedy weaknesses in our nuclear security regime.' The amended CPPNM makes it legally binding for States Parties to protect nuclear facilities and material in peaceful domestic use, storage as well as transport. It will also provide for expanded cooperation between and among States regarding rapid measures to locate and recover stolen or smuggled nuclear material, mitigate any radiological consequences of sabotage, and prevent and combat related offences. The original CPPNM applied only to nuclear material in international transport. Conference President Dr. Alec Baer said 'All 89 delegations demonstrated real unity of purpose. They put aside some very genuine national concerns in favour of the global interest and the result is a much improved convention that is better suited to addressing the nuclear security challenges we currently face.' The new rules will come into effect once they have been ratified by two-thirds of the 112 States Parties of the Convention, expected to take several years. 'But concrete actions are already taking place around the world. For more than 3 years, the IAEA has been implementing a systematic Nuclear Security plan, including physical protection activities designed to prevent, detect and respond to malicious acts,' said Anita Nillson, Director of the IAEA's Office of Nuclear Security. The Agency's Nuclear Security Fund, set up after the events of 9/11, has delivered $19.5 million in practical assistance to 121 countries

  3. Boundary between Stable and Unstable Regimes of Accretion. Ordered and Chaotic Unstable Regimes

    CERN Document Server

    Blinova, A A; Lovelace, R V E

    2015-01-01

    We search for the boundary between stable and Rayleigh-Taylor unstable regimes of accretion to magnetized stars in a new set of high grid resolution simulations. We found that the boundary between stable and unstable regimes is mainly determined by the ratio of the corotation radius r_cor (where the Keplerian angular velocity in the disc matches the angular velocity of the star) to the magnetospheric radius r_m (where the magnetic stress in the magnetosphere matches the matter stress in the disc). Instability is stronger when r_cor is larger with respect to r_m, that is, when the gravitational force is larger than the centrifugal force at the inner disc. In the cases of a small tilt of the magnetosphere, Theta=5 deg, and a small alpha-parameter of viscosity, alpha=0.02, the boundary is located at r_cor approx. 1.4 r_m. Instability becomes stronger at higher values of viscosity, and occurs at lower values of r_cor/r_m. At higher values of Theta, the variability associated with instability decreases. Simulation...

  4. An Examination of the Nature of Global MODIS Cloud Regimes

    Science.gov (United States)

    Oreopoulos, Lazaros; Cho, Nayeong; Lee, Dongmin; Kato, Seiji; Huffman, George J.

    2014-01-01

    We introduce global cloud regimes (previously also referred to as "weather states") derived from cloud retrievals that use measurements by the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument aboard the Aqua and Terra satellites. The regimes are obtained by applying clustering analysis on joint histograms of retrieved cloud top pressure and cloud optical thickness. By employing a compositing approach on data sets from satellites and other sources, we examine regime structural and thermodynamical characteristics. We establish that the MODIS cloud regimes tend to form in distinct dynamical and thermodynamical environments and have diverse profiles of cloud fraction and water content. When compositing radiative fluxes from the Clouds and the Earth's Radiant Energy System instrument and surface precipitation from the Global Precipitation Climatology Project, we find that regimes with a radiative warming effect on the atmosphere also produce the largest implied latent heat. Taken as a whole, the results of the study corroborate the usefulness of the cloud regime concept, reaffirm the fundamental nature of the regimes as appropriate building blocks for cloud system classification, clarify their association with standard cloud types, and underscore their distinct radiative and hydrological signatures.

  5. Marine regime shifts: drivers and impacts on ecosystems services

    Science.gov (United States)

    Rocha, J.; Yletyinen, J.; Biggs, R.; Blenckner, T.; Peterson, G.

    2015-01-01

    Marine ecosystems can experience regime shifts, in which they shift from being organized around one set of mutually reinforcing structures and processes to another. Anthropogenic global change has broadly increased a wide variety of processes that can drive regime shifts. To assess the vulnerability of marine ecosystems to such shifts and their potential consequences, we reviewed the scientific literature for 13 types of marine regime shifts and used networks to conduct an analysis of co-occurrence of drivers and ecosystem service impacts. We found that regime shifts are caused by multiple drivers and have multiple consequences that co-occur in a non-random pattern. Drivers related to food production, climate change and coastal development are the most common co-occurring causes of regime shifts, while cultural services, biodiversity and primary production are the most common cluster of ecosystem services affected. These clusters prioritize sets of drivers for management and highlight the need for coordinated actions across multiple drivers and scales to reduce the risk of marine regime shifts. Managerial strategies are likely to fail if they only address well-understood or data-rich variables, and international cooperation and polycentric institutions will be critical to implement and coordinate action across the scales at which different drivers operate. By better understanding these underlying patterns, we hope to inform the development of managerial strategies to reduce the risk of high-impact marine regime shifts, especially for areas of the world where data are not available or monitoring programmes are not in place.

  6. Shearing box simulations in the Rayleigh unstable regime

    CERN Document Server

    Nauman, Farrukh

    2015-01-01

    We study the stability properties of Rayleigh unstable flows both in the purely hydrodynamic and magnetohydrodynamic (MHD) regimes for two different values of the shear $q=2.1, 4.2$ ($q = - d\\ln\\Omega / d\\ln r$) and compare it with the Keplerian case $q=1.5$. The Rayleigh stability criterion states that hydrodynamic shear flows are stable for $q2$ regime as the volume averaged velocities ($k=0$ mode) are unstable in this regime but the advantage of using a pseudospectral code is that the $k=0$ mode is conserved. We find that the $q>2$ regime is unstable to turbulence both in the hydrodynamic and in the MHD limit (with an initially weak magnetic field). In the $q>2$ regime, the velocity fluctuations dominate the magnetic fluctuations whereas in the $q2$ regime the instability produces primarily velocity fluctuations that cause magnetic fluctuations, with the causality reversed for the $q<2$ MRI unstable regime. We also find that the magnetic field correlation is increasingly localized as the shear is increa...

  7. Perspectives on the International and Internal Nuclear Security Regime

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Sung Soon [Korea Nuclear Non-proliferation and Control, Daejeon (Korea, Republic of)

    2015-10-15

    The term, 'Nuclear Security' became more familiar to Korean public after the government hosted 2012 Seoul Nuclear Security Summit. Nuclear Security is prevention of, detection of and response to criminal or intentional unauthorized acts involving or directed at nuclear material, other radioactive material, associated facilities, or associated activities. Nuclear Security includes physical protection, security of radioactive sources, nuclear forensics, nuclear smuggling prevention, border monitoring, and cyber security with regard to nuclear and other radiological materials. This abstract will review recent international trends and discuss the nuclear security regime in the Republic of Korea (ROK). The international Nuclear Security Regime has been strengthened. The upcoming Chicago Summit in 2016 and the entry into force of the Amendment of Convention on Physical Protection of Nuclear Materials (CPPNM) will bring major changes in nuclear security. The Republic of Korea hosted the 2012 Seoul Summit and strengthened domestic regime to meet international standards. The ROK has worked hard to contribute to the international security regime and to establish a robust domestic security regime against terrorist threats. Even if the nuclear security regime is robust, Risk-informed Nuclear Security management should be established to meet international standards and to implement effective as well as an efficient nuclear security regime.

  8. Conceptualization of UN Peacekeeping as an International Regime

    Directory of Open Access Journals (Sweden)

    Jana Urbanovská

    2012-12-01

    Full Text Available It is widely recognized that UN peacekeeping operations are an undertheorized topic. In this respect, scholars call to devote more attention to the incorporation of the study of UN peacekeeping operations into the framework of international relations theories. The article responds to these calls and suggests conceptualizing UN peacekeeping as an international regime. Some authors have already referred to UN peacekeeping as an international regime, however, the references have been rather fragmentary and there is no detailed identification of individual dimensions of this regime. The article uses the conception of Stephen Krasner who defines regimes as “principles, norms, rules, and decision-making procedures around which actors’ expectations converge in a given area of international relations” to carefully identify and characterize the dimensions of the UN peacekeeping regime. The conceptualization of UN peacekeeping as an international regime is understood as a first and necessary step to opening new ground to the theoretical study of UN peacekeeping operations within the regime analysis.

  9. The NPT regime: Progress and promises

    International Nuclear Information System (INIS)

    Full text: Thesis. The 'NPT regime' has arrived at a fateful crossroads. Though extended indefinitely in 1995, its future is my no means secure. The future 'progress' of this treaty will depend upon whether the 'promises' of its States parties are fully implemented and, eventually, upon the treaty's success in achieving fully universal membership. Challenges The treaty faces many short-term and longer-term challenges: Short term - The first Preparatory Committee meeting for the 2005 Review Conference will meet next year. NNWS will want to see some evidence of progress on nuclear disarmament (Art. VI), along the lines prescribed in the 13 'practical steps' agreed at the last Review Conference. Yet progress has been set back by: uncertainties over the future of the ABM Treaty; the failure of START II and the CTBT to enter into force; the lack of a FISMAT treaty and a treaty establishing a NWFZ in Central Asia; continued qualitative improvements in nuclear weapons; hints that nuclear testing may one day resume; the persistence of doctrines of first-use, pre-emptive use, and use against states that use CBW. Other compliance-related questions will arise over safeguards (e.g. the inability of the IAEA to conduct inspections in the DPRK; signs of a breakdown of the norm of full-scope IAEA safeguards, e.g. in South Asia). There are also concerns over the implementation of non-proliferation commitments (e.g. persisting allegations about nuclear weapon programmes in existing NNWS). The terrorist attacks in New York and Washington, D.C. on 11 September should also serve as a reminder of the new terrorist dangers relating to the possible use of weapons of mass destruction and unorthodox delivery systems. Longer term - Selectivity in the enforcement of NPT norms; unilateralism; IAEA funding uncertainties and shortfalls; difficulties in reaching universal membership (India, Pakistan, and Israel); continuing compliance problems with respect to both non-proliferation and

  10. Past and Future Drought Regimes in Turkey

    Science.gov (United States)

    Sen, Burak; Topcu, Sevilay; Turkes, Murat; Sen, Baha

    2010-05-01

    Climate variability in the 20th century was characterized by apparent precipitation variability at both temporal and spatial scales. In addition to the well-known characteristic seasonal and year-to-year variability, some marked and long-term changes in precipitation occurred in Turkey, particularly after the early 1970s. Drought, originating from a deficiency of precipitation over an extended time period (which is usually a season or more) has become a recurring phenomenon in Turkey in the past few decades. Spatially coherent with the significant drought events since early 1970s, water stress and shortages for all water user sectors have also reached their critical points in Turkey. Analyzing the historical occurrence of drought provides an understanding of the range of climate possibilities for a country, resulting in more informed management decision-making. However, future projections about spatial and temporal changes in drought characteristics such as frequency, intensity and duration can be challenging for developing appropriate mitigation and adaptation strategies. Hence, the objectives of this study are (i) to analyze the spatial and temporal dimensions of historical droughts in Turkey, (2) to predict potential intensity, frequency and duration of droughts in Turkey for the future (2070-2100). The Standardized Precipitation Index (SPI) and the Percent to Normal Index (PNI) have been used to assess the drought characteristics. Rainfall datasets for the reference period, 1960-1990, were acquired from 52 stations (representative of all kinds of regions with different rainfall regimes in the country) of the Turkish State Meteorological Service (TSMS). The future rainfall series for the 2070-2100 period were simulated using a regional climate model (RegCM3) for IPCC's SRESS-A2 scenario conditions. For verification of RegCM3 simulations, the model was performed for the reference period and simulated rainfall data were used for computing two drought indices (SPI

  11. Considerations on nonproliferation regime meeting in a changing world

    Energy Technology Data Exchange (ETDEWEB)

    Kurihara, Hiroyoshi; Kikuchi, Masahiro [Nuclear Material Control Center, Tokyo (Japan)

    1994-12-31

    This paper summarizes the past history of worldwide nonproliferation regime, then proposes the future improvements on the regime. Present worldwide nonproliferation regime have been formulated during the cold war era. Therefore, the structure and measures of the regime were heavily influenced by the features of cold war era. Though the cold war was over, still new international order does not seem to be on the horizon, we need to review the present regime and to improve the regime compatible to new world situation. Generally speaking, the nonproliferation regime have gained moderate success so far. We could point out the following features as a kind of success: (1) No increase of overt Nuclear Weapon State (NWS), (2) All five NWSs have finally participated to the NPT, (3) South Africa has destroyed its nuclear weapons and became Non-Nuclear Weapon State (NNWS), (4) Successful conclusions of some regional arrangements, such as Tlatelolco, Ralotonga, and (5) Strengthening of export control on sensitive items. On the other hand, we recognize the following points as the failures of the regime. (6) India, Pakistan and Israel reject to join the NPT, (7) Existence of some violation against NPT regime, i.e. Iraqi case and DPRK case, (8) Insufficient effective measures against brain drain problem, (9) Risk exists for the long term extension of NPT, and (10) Insufficient flexibility to meet changing boundary conditions. We would propose the various measures for strengthening to meet changing boundary conditions, as follows: (11) Measures to be taken along with future civil use of Plutonium, (12) Strengthening and rationalizing international safeguards, (13) Countermeasures for emerging new types of nuclear proliferation, (14) Strengthening nuclear material control in NWS, (15) Measures to be taken for nuclear material from dismantled nuclear weapons, and (16) Nuclear disarmament. (author).

  12. Laserlike and atomlike regimes in a one-atom laser

    OpenAIRE

    Boozer, A. D.

    2008-01-01

    We consider a three-level model of a one-atom laser, and show that there are two limiting regimes of parameter space, one in which the system behaves like a conventional laser and one in which the system exhibits novel quantum properties. We show that in the first limiting regime, the model can be approximated by semiclassical laser theory, and in the second limiting regime the model can be approximated as an effective two-level atom. We also perform numerical simulations that confirm the lim...

  13. Diversity-Multiplexing Tradeoff in the Low-SNR Regime

    CERN Document Server

    Loyka, Sergey

    2011-01-01

    An extension of the popular diversity-multiplexing tradeoff framework to the low-SNR (or wideband) regime is proposed. The concept of diversity gain is shown to be redundant in this regime since the outage probability is SNR-independent and depends on the multiplexing gain and the channel power gain statistics only. The outage probability under the DMT framework is obtained in an explicit, closed form for a broad class of channels. The low and high-SNR regime boundaries are explicitly determined for the scalar Rayleigh-fading channel, indicating a significant limitation of the SNR-asymptotic DMT when the multiplexing gain is small.

  14. Nonlinear Regime of a Single-mode CSR Instability

    International Nuclear Information System (INIS)

    Close to the shielding threshold of synchrotron radiation in a toroidal waveguide the coherent synchrotron radiation (CSR) instability may be driven by a single synchronous mode. The linear analysis of the problem is presented elsewhere. In this paper we study a nonlinear regime of the single-mode CSR instability. We show that in the nonlinear regime the instability is described by a system of equations which, after a proper scaling, coincides with the 1D FEL instability theory. We present numeric and analytic analysis of the non-linear regime for the time interval large compared with the damping time taking into account radiation damping and diffusion due to the quantum fluctuations

  15. Formations and transformations of language regimes: Turkey, a case study

    OpenAIRE

    Balçık, Mehmet Berk; Balcik, Mehmet Berk

    2009-01-01

    There are two main aims of this dissertation: to present a legal and ideological history of the formation of the language regime in Turkey in the Republican period; and to analyze its transformation in the post-1980 era. A language regime is defined in this dissertation as a de jure or de facto regulation of the linguistic behavior, in its content or in its status, within a space of communicative action, such as that of a nation-state or a speech group. In other words, a language regime is a ...

  16. Raman amplification in the broken-wave regime

    CERN Document Server

    Farmer, John P

    2015-01-01

    In regimes far beyond the wavebreaking theshold of Raman amplification, we show that significant amplifcation can occur after the onset of wavebreaking, before phase mixing destroys the coupling between pump and probe. The amplification efficiency in this regime is therefore strongly dependent on the energy-transfer rate when wavebreaking occurs, and is, as such, sensitive to both the probe amplitude and profile. In order to access the higher-efficiency broken-wave regime, a short, intense probe is required. Parameter scans show the marked difference in behaviour compared to below wavebreaking, where longer, more energetic pulses lead to improved efficiencies.

  17. Policy Ideas, Knowledge Regimes and Comparative Political Economy

    DEFF Research Database (Denmark)

    Campbell, John L.; Pedersen, Ove K.

    2015-01-01

    Despite much attention to how ideas affect policy making, where these ideas come from is a blind spot in comparative political economy. We show that an important source of policy ideas are knowledge regimes—fields of policy research organizations. We show as well that the organization of knowledge...... regimes is heavily influenced by the organization of their surrounding political economies such that knowledge regimes have particular national characters. Furthermore, when people perceive that the utility of their knowledge regime for the rest of the political economy breaks down, they often try......, France and Germany. Theoretical implications are explored for two literatures in comparative political economy: ideational analysis and the varieties of capitalism....

  18. Regime-Switching Risk: To Price or Not to Price?

    Directory of Open Access Journals (Sweden)

    Tak Kuen Siu

    2011-01-01

    “normative” issues to be addressed in pricing contingent claims under a Markovian, regime-switching, Black-Scholes-Merton model. We address this issue using a minimal relative entropy approach. Firstly, we apply a martingale representation for a double martingale to characterize the canonical space of equivalent martingale measures which may be viewed as the largest space of equivalent martingale measures to incorporate both the diffusion risk and the regime-switching risk. Then we show that an optimal equivalent martingale measure over the canonical space selected by minimizing the relative entropy between an equivalent martingale measure and the real-world probability measure does not price the regime-switching risk. The optimal measure also justifies the use of the Esscher transform for option valuation in the regime-switching market.

  19. Regime shifts and resilience in China's coastal ecosystems.

    Science.gov (United States)

    Zhang, Ke

    2016-02-01

    Regime shift often results in large, abrupt, and persistent changes in the provision of ecosystem services and can therefore have significant impacts on human wellbeing. Understanding regime shifts has profound implications for ecosystem recovery and management. China's coastal ecosystems have experienced substantial deterioration within the past decades, at a scale and speed the world has never seen before. Yet, information about this coastal ecosystem change from a dynamics perspective is quite limited. In this review, I synthesize existing information on coastal ecosystem regime shifts in China and discuss their interactions and cascading effects. The accumulation of regime shifts in China's coastal ecosystems suggests that the desired system resilience has been profoundly eroded, increasing the potential of abrupt shifts to undesirable states at a larger scale, especially given multiple escalating pressures. Policy and management strategies need to incorporate resilience approaches in order to cope with future challenges and avoid major losses in China's coastal ecosystem services.

  20. Spacetime-noncommutativity regime of Loop Quantum Gravity

    CERN Document Server

    Amelino-Camelia, Giovanni; Ronco, Michele; Cesarini, Lorenzo; Lecian, Orchidea Maria

    2016-01-01

    A recent study by Bojowald and Paily provided a path toward the identification of an effective quantum-spacetime picture of Loop Quantum Gravity, applicable in the "Minkowski regime", the regime where the large-scale (coarse-grained) spacetime metric is flat. A pivotal role in the analysis is played by Loop-Quantum-Gravity-based modifications to the hypersurface deformation algebra, which leave a trace in the Minkowski regime. We here show that the symmetry-algebra results reported by Bojowald and Paily are consistent with a description of spacetime in the Minkowski regime given in terms of the $\\kappa$-Minkowski noncommutative spacetime, whose relevance for the study of the quantum-gravity problem had already been proposed for independent reasons.

  1. A new regime for future telecommunication network operations

    NARCIS (Netherlands)

    Gustafsson, S.; Trommelen, P.H.; Vos, C. de

    2010-01-01

    The increasingly crucial role that telecommunications plays in today's information society calls for a new regime for telecommunication network operations. An unbundling of business roles and associated responsibilities is proposed, providing more economic network operations and higher availability

  2. The Hadley and Rossby regimes in a spherical atmosphere

    Science.gov (United States)

    Feldstein, S. B.; Clark, J. H. E.

    1985-01-01

    The properties of the steady Hadley and Rossby regimes for a thermally forced rotating fluid on a sphere are studied. The two layer modified geostrophic model is employed which allows for thermal advection by the divergent wind and time dependent static stability. Heating processes are parameterized using the Newtonian approximation and Rayleigh friction is accounted for. The equations are transformed to spectral form using spherical harmonics and then truncated retaining a simple axisymmetric state and initial, one wave. A time independent Hadley circulation is obtained which is neutral to axisymmetric disturbances but unstable to wave like perturbations for intermediate values of the meridional temperature gradient, indicating the existence of both an upper and lower symmetric Hadley regime. An analytical solution for the steady Rossby circulation is determined for values of the meridional temperature gradient where the Hadley regime is unstable. Linear perturbation theory is used to show that within the steady Rossby regime two or more waves cannot exist simultaneously.

  3. Capillary Breakup of a Liquid Bridge: Identifying Regimes and Transitions

    CERN Document Server

    Li, Yuan

    2016-01-01

    Computations of the breakup of a liquid bridge are used to establish the limits of applicability of similarity solutions derived for different breakup regimes. These regimes are based on particular viscous-inertial balances, that is different limits of the Ohnesorge number $Oh$. To accurately establish the transitions between regimes, the minimum bridge radius is resolved through four orders of magnitude using a purpose-built multiscale finite element method. This allows us to construct a quantitative phase diagram for the breakup phenomenon which includes the appearance of a recently discovered low-$Oh$ viscous regime. The method used to quantify the accuracy of the similarity solutions allows us to identify a number of previously unobserved features of the breakup, most notably an oscillatory convergence towards the viscous-inertial similarity solution. Finally, we discuss how the new findings open up a number of challenges for both theoretical and experimental analysis.

  4. Determination of three characteristic regimes of weakly charged polyelectrolytes monolayers

    International Nuclear Information System (INIS)

    We have demonstrated that monolayer films of randomly charged polystyrene sulfonated acid (PSSA) can be produced by the Langmuir technique, and observed the micro-domain structures, produced by the phase separation of electrostatically charged moieties and the hydrophobic moieties. Using atomic force microscopy and Langmuir isotherm, we found three specific regimes for the polyelectrolytes with various degrees of sulfonation (4-35%); very low charged PSSA (4-5%) in the hydrophobic regime, moderately charged PSSA (6-16%) which possessed a well-balanced nature between electrostatic and the hydrophobic interactions, and strongly amphiphilic nature of PSSA (6-16%) in the ionomer regime. Finally, we could categorize PSSA 35% in the polyelectrolyte regime, due to the dominance of the electrostatic interactions over the hydrophobic interactions

  5. Evolving International Trade and Monetary Regimes and Related Policy Issues

    OpenAIRE

    Kumiharu Shigehara

    1991-01-01

    This essay focuses on some aspects of policy issues relating to evolving international trade and monetary regimes, and patterns of national saving and investment balances conducive to better global economic performance.

  6. Quantifying flooding regime in floodplain forests to guide river restoration

    OpenAIRE

    Christian O. Marks; Keith H Nislow; Magilligan, Francis J.

    2014-01-01

    Abstract Determining the flooding regime needed to support distinctive floodplain forests is essential for effective river conservation under the ubiquitous human alteration of river flows characteristic of the Anthropocene Era. At over 100 sites throughout the Connecticut River basin, the largest river system in New England, we characterized species composition, valley and channel morphology, and hydrologic regime to define conditions promoting distinct floodplain forest assemblages. Species...

  7. Shock-Induced Flows through Packed Beds: Transient Regimes

    CERN Document Server

    Shtemler, Yuri M; Britan, Alex

    2006-01-01

    The early stage of the transient regimes in the shock-induced flows within solid-packed beds are investigated in the linear longwave and high-frequency approximation. The transient resistance law is refined as the Duhameltime integral that follows from the general concept of dynamic tortuosity and compressibility of the packed beds. A closed-form solution is expected to describe accurately the early stage of the transient regime flow and is in qualitative agreement with available experimental data.

  8. Capital Controls and the Timing of Exchange Regime Collapse

    OpenAIRE

    Daekuen Park; Jeffrey Sachs

    1987-01-01

    This paper investigates the nature of balance of payments crises in regimes with capital controls. It extends earlier work on capital controls by assuming that households manage their consumption and asset portfolios to maximize intertemporal utility. Our main result is that capital controls are effective in delaying, but not preventing, a breakdown of a fixed exchange rate regime in the presence of money-financed fiscal deficits.

  9. Constructing a Transnational Timber Legality Assurance Regime: Architecture, Accomplishments, Challenges

    OpenAIRE

    Overdevest, C.; Zeitlin, J

    2013-01-01

    The emerging transnational timber legality assurance regime comprises a set of interrelated policy instruments, both public and private, aimed at controlling trade in illegally logged wood and wood products. The potentially productive interactions among these instruments in the emerging forestry regime create prospects for engendering learning, stimulating cross-fertilization, and enhancing accountability. In this article, we analyze the EU's Forest Law Enforcement Governance and Trade (FLEGT...

  10. Were there regime switches in U.S. monetary policy?

    OpenAIRE

    Christopher A. Sims; Zha, Tao

    2004-01-01

    A multivariate model, identifying monetary policy and allowing for simultaneity and regime switching in coefficients and variances, is confronted with U.S. data since 1959. The best fit is with a model that allows time variation in structural disturbance variances only. Among models that also allow for changes in equation coefficients, the best fit is for a model that allows coefficients to change only in the monetary policy rule. That model allows switching among three main regimes and one r...

  11. Laboratory experiment on boundaries of upper stage plane bed regime

    Science.gov (United States)

    Zrostlík, Štěpán; Matoušek, Václav

    2016-04-01

    Results are discussed of laboratory experiments on criteria determining the transition between the regime of dunes and the upper stage plane bed (UPB) regime and the transition between the UPB regime and the regime of wavy flow. The experiments were carried for 3 fractions of plastic material and two fractions of glass beads in a broad range of flow conditions (different discharges of water and solids and longitudinal bed slopes) in a tilting flume. The experiments reveal that, contrary to expectations, a constant value of the Shields parameter is not an appropriate criterion for the transition between the dune regime and the UPB regime. Furthermore, the transition appears to be insensitive to the total discharge of solids and water. Instead, the criterion seems to be well represented by a constant value of the average transport concentration of sediment (the ratio of volumetric discharge of solids and volumetric discharge of mixture). The experimental results exhibit a very tight correlation between the transport concentration and the longitudinal bed slope. Hence, a constant value of the bed slope can be considered an appropriate criterion for the transition. The transition between the UPB regime and the wavy regime (significant waves develop but they are not always standing waves) is found at a constant value of Froude number, which is in agreement with literature, although it is found at a higher value than the literature usually suggests (Fr = 1.2 instead of 1.0). Hence, the transition occurs in the super-critical flow but it is not necessarily associated with the critical flow.

  12. Generating Schemes for Long Memory Processes: Regimes, Aggregation and Linearity

    OpenAIRE

    Davidson, James; Sibbertsen, Philipp

    2002-01-01

    This paper analyses a class of nonlinear time series models exhibiting long memory. These processes exhibit short memory fluctuations around a local mean (regime) which switches randomly such that the durations of the regimes follow a power law. We show that if a large number of independent copies of such a process are aggregated, the resulting processes are Gaussian, have a linear representation, and converge after normalisation to fractional Brownian motion. Two cases arise, a stationary ca...

  13. Et dansk regime for overgang fra uddannelse til arbejde?

    DEFF Research Database (Denmark)

    Jørgensen, Christian Helms

    2008-01-01

    I dette kapitel vil jeg først gennemgå en række forskningstilgange som på forskellig måde kan begribe de særlige træk ved unges overgang i Danmark i det man kan kalde et dansk 'regime for overgang' (transition regime). Dernæst følger en mere beskrivende gennemgang af det danske uddannelsessystem ...

  14. Real Output and Prices Adjustments under Different Exchange Rate Regimes

    OpenAIRE

    Rajmund MIRDALA

    2013-01-01

    Exchange rate regimes evolution in the European transition economies refers to one of the most crucial policy decision in the beginning of the 1990s employed during the initial stages of the transition process. During the period of last two decades we may identify some crucial milestones in the exchange rate regimes evolution in the European transition economies. due to existing diversity in exchange rate arrangements in the European transition economies in the pre-ERM2 period there seems to ...

  15. Sensitivity of streamflows to hydroclimatic fluctuations: resilience and regime shifts

    Science.gov (United States)

    Botter, Gianluca; Basso, Stefano; Rodriguez-Iturbe, Ignacio; Rinaldo, Andrea

    2016-04-01

    Landscape and climate alterations foreshadow global-scale shifts of river flow regimes. However, a theory that identifies the range of foreseen impacts on streamflows resulting from inhomogeneous forcings and sensitivity gradients across diverse regimes is lacking. In this contribution, we use a dimensionless index embedding simple climate and landscape attributes (the ratio of the mean interarrival of streamflow-producing rainfall events and the mean catchment response time) to discriminate erratic regimes with enhanced intra-seasonal streamflow variability from persistent regimes endowed with regular flow patterns. The proposed classification is successfully applied to 110 seasonal streamflow distributions observed in 44 catchments of the Alps and the United States, allowing the identification of emerging patterns in space and time. In the same framework, the impact of multi-scale fluctuations of the underlying climatic drivers (temperature, precipitation) on the streamflow distributions can be analyzed. Theoretical and empirical data show that erratic regimes, typical of rivers with low mean discharges, are highly resilient in that they hold a reduced sensitivity to variations in the external forcing. Specific temporal trajectories of streamflow distributions and flow regime shifts driven by land-cover change and rainfall patterns can be also evidenced. The approach developed offers an objective basis for the analysis and prediction of the impact of climate/landscape change on water resources.

  16. International regime formation: Ozone depletion and global climate change

    Energy Technology Data Exchange (ETDEWEB)

    Busmann, N.E.

    1994-03-01

    Two theoretical perspectives, neorealism and neoliberal institutionalism, dominate in international relations. An assessment is made of whether these perspectives provide compelling explanations of why a regime with specific targets and timetables was formed for ozone depletion, while a regime with such specificity was not formed for global climate change. In so doing, the assumptions underlying neorealism and neoliberal institutionalism are examined. A preliminary assessment is offered of the policymaking and institutional bargaining process. Patterns of interstate behavior are evolving toward broader forms of cooperation, at least with regard to global environmental issues, although this process is both slow and cautious. State coalitions on specific issues are not yet powerful enough to create a strong community of states in which states are willing to devolve power to international institutions. It is shown that regime analysis is a useful analytic framework, but it should not be mistaken for theory. Regime analysis provides an organizational framework offering a set of questions regarding the principles and norms that govern cooperation and conflict in an issue area, and whether forces independent of states exist which affect the scope of state behavior. An examination of both neorealism and neoliberal institutionalism, embodied by four approaches to regime formation, demonstrates that neither has sufficient scope to account for contextual dynamics in either the ozone depletion or global climate change regime formation processes. 261 refs.

  17. Development of Risk Assessment Methodology for State's Nuclear Security Regime

    International Nuclear Information System (INIS)

    Threats of nuclear terrorism are increasing after 9/11 terrorist attack. Treats include nuclear explosive device (NED) made by terrorist groups, radiological damage caused by a sabotage aiming nuclear facilities, and radiological dispersion device (RDD), which is also called 'dirty bomb'. In 9/11, Al Qaeda planed to cause radiological consequences by the crash of a nuclear power plant and the captured airplane. The evidence of a dirty bomb experiment was found in Afganistan by the UK intelligence agency. Thus, the international communities including the IAEA work substantial efforts. The leaders of 47 nations attended the 2010 nuclear security summit hosted by President Obama, while the next global nuclear summit will be held in Seoul, 2012. Most states established and are maintaining state's nuclear security regime because of the increasing threat and the international obligations. However, each state's nuclear security regime is different and depends on the state's environment. The methodology for the assessment of state's nuclear security regime is necessary to design and implement an efficient nuclear security regime, and to figure out weak points. The IAEA's INPRO project suggests a checklist method for State's nuclear security regime. The IAEA is now researching more quantitative methods cooperatively with several countries including Korea. In this abstract, methodologies to evaluate state's nuclear security regime by risk assessment are addressed

  18. Oscillations of a highly discrete breather with a critical regime

    Science.gov (United States)

    Coquet; Remoissenet; Dinda

    2000-10-01

    We analyze carefully the essential features of the dynamics of a stationary discrete breather in the ultimate degree of energy localization in a nonlinear Klein-Gordon lattice with an on-site double-well potential. We demonstrate the existence of three different regimes of oscillatory motion in the breather dynamics, which are closely related to the motion of the central particle in an effective potential having two nondegenerate wells. In given parameter regions, we observe an untrapped regime, in which the central particle executes large-amplitude oscillations from one to the other side of the potential barrier. In other parameter regions, we find the trapped regime, in which the central particle oscillates in one of the two wells of the effective potential. Between these two regimes we find a critical regime in which the central particle undergoes several temporary trappings within an untrapped regime. Importantly, our study reveals that in the presence of purely anharmonic coupling forces, the breather compactifies, i.e., the energy becomes abruptly localized within the breather.

  19. History of Uranium-233(233U)Processing at the Rocky Flats Plant. In support of the RFETS Acceptable Knowledge Program

    International Nuclear Information System (INIS)

    This report documents the processing of Uranium-233 at the Rocky Flats Plant (Rocky Flats Environmental Technology Site). The information may be used to meet Waste Isolation Pilot Plant (WIPP) Waste Acceptance Criteria (WAC)and for determining potential Uranium-233 content in applicable residue waste streams

  20. Contribution to the study of {sup 233}U production with MOX-ThPu fuel in PWR reactor. Transition scenarios towards Th/{sup 233}U iso-generating concepts in thermal spectrum. Development of the MURE fuel evolution code; Contribution a l'etude de la production d'{sup 233}U en combustible MOX-ThPu en reacteur a eau sous pression. Scenarios de transition vers des concepts isogenerateurs Th/{sup 233}U en spectre thermique. Developpement du code MURE d'evolution du combustible

    Energy Technology Data Exchange (ETDEWEB)

    Michel-Sendis, F

    2006-12-15

    If nuclear power is to provide a significant fraction of the growing world energy demand, only through the breeding concept can the development of sustainable nuclear energy become a reality. The study of such a transition, from present-day nuclear technologies to future breeding concepts is therefore pertinent. Among these future concepts, those using the thorium cycle Th/U-233 in a thermal neutron spectrum are of particular interest; molten-salt type thermal reactors would allow for breeding while requiring comparatively low initial inventories of U-233. The upstream production of U-233 can be obtained through the use of thorium-plutonium mixed oxide fuel in present-day light water reactors. This work presents, firstly, the development of the MURE evolution code system, a C++ object-oriented code that allows the study, through Monte Carlo (M.C.) simulation, of nuclear reactors and the evolution of their fuel under neutron irradiation. The M.C. methods are well-suited for the study of any reactor, whether it'd be an existing reactor using a new kind of fuel or a future concept altogether, the simulation is only dependent on nuclear data. Exact and complex geometries can be simulated and continuous energy particle transport is performed. MURE is an interface with MCNP, the well-known and validated transport code, that allows, among other functionalities, to simulate constant power and constant reactivity evolutions. Secondly, the study of MOX ThPu fuel in a conventional light water reactor (REP) is presented; it explores different plutonium concentrations and isotopic qualities in order to evaluate their safety characteristics. Simulation of their evolution allows us to quantify the production of U-233 at the end of burnup. Last, different french scenarios validating a possible transition towards a park of thermal Th/U-233 breeders, are presented. In these scenarios, U-233 is produced in ThPu moxed light water reactors. (author)

  1. Radiochemical method for the simultaneous determination of 233U, 236U, 237Np, 236Pu, 238Pu, and 239Pu in biological materials

    International Nuclear Information System (INIS)

    A radiochemical method has been developed for the determination of multiple isotopes of uranium, neptunium, and plutonium in biological materials. The elements are separated from the other sample constituents and from each other by anion exchange in halide media. Their recoveries are monitored by isotopic diluents. The amounts of the analyte and diluent isotopes of each element are measured alpha spectrometrically. The interelemental separation factors are generally greater than 102, and the recovery of each element ranges from 60% to 90%. 4 references, 1 table

  2. Stochastic Parametrisations and Regime Behaviour of Atmospheric Models

    Science.gov (United States)

    Arnold, Hannah; Moroz, Irene; Palmer, Tim

    2013-04-01

    The presence of regimes is a characteristic of non-linear, chaotic systems (Lorenz, 2006). In the atmosphere, regimes emerge as familiar circulation patterns such as the El-Nino Southern Oscillation (ENSO), the North Atlantic Oscillation (NAO) and Scandinavian Blocking events. In recent years there has been much interest in the problem of identifying and studying atmospheric regimes (Solomon et al, 2007). In particular, how do these regimes respond to an external forcing such as anthropogenic greenhouse gas emissions? The importance of regimes in observed trends over the past 50-100 years indicates that in order to predict anthropogenic climate change, our climate models must be able to represent accurately natural circulation regimes, their statistics and variability. It is well established that representing model uncertainty as well as initial condition uncertainty is important for reliable weather forecasts (Palmer, 2001). In particular, stochastic parametrisation schemes have been shown to improve the skill of weather forecast models (e.g. Berner et al., 2009; Frenkel et al., 2012; Palmer et al., 2009). It is possible that including stochastic physics as a representation of model uncertainty could also be beneficial in climate modelling, enabling the simulator to explore larger regions of the climate attractor including other flow regimes. An alternative representation of model uncertainty is a perturbed parameter scheme, whereby physical parameters in subgrid parametrisation schemes are perturbed about their optimal value. Perturbing parameters gives a greater control over the ensemble than multi-model or multiparametrisation ensembles, and has been used as a representation of model uncertainty in climate prediction (Stainforth et al., 2005; Rougier et al., 2009). We investigate the effect of including representations of model uncertainty on the regime behaviour of a simulator. A simple chaotic model of the atmosphere, the Lorenz '96 system, is used to study

  3. Positron acceleration in doughnut wakefields in the blowout regime

    Science.gov (United States)

    Vieira, Jorge; Mendonca, Jose; Fonseca, Ricardo; Silva, Luis

    2014-10-01

    Most important plasma acceleration results were reached in the so called bubble or blowout regime. Although ideally suited for electron acceleration, it has been recognized that non-linear regimes are not adequate to accelerate positrons. New configurations enabling positron acceleration in non-linear regimes would therefore open new research paths for future plasma based collider configurations. In this work, we explore, analytically and through 3D OSIRIS simulations, a novel configuration for positron acceleration in strongly non-linear laser wakefield excitation regimes using Laguerre-Gaussian laser drivers to drive doughnut shaped wakefields with positron focusing and accelerating fields. We demonstrate that positron focusing-fields can be up to an order of magnitude larger than electron focusing in the spherical blowout regime. The amplitude of the accelerating fields is similar to the spherical blowout. Simulations demonstrate laser self-guiding and stable positron acceleration until the laser energy has been exhausted to the plasma. Other realisations of the scheme, using two Gaussian laser pulses, will also be explored. FCT Grant No EXPL/FIS-PLA/0834/2012 and European Research Council ERC-2010-AdG Grant No. 267841.

  4. Early signatures of regime shifts in complex dynamical systems

    Indian Academy of Sciences (India)

    Indrani Bose; Mainak Pal

    2015-02-01

    A large number of studies have recently been carried out on the early signatures of regime shifts in a number of dynamical systems, e.g., ecosystems, the climate, fish and wildlife populations, financial markets, complex diseases and gene circuits. The underlying model in most cases is that of the fold-bifurcation in which a sudden regime shift occurs at a bifurcation point. The shift involves a discontinuous jump from one type of stable steady state to another. The dynamics of natural systems have both deterministic and stochastic components. The early signatures of abrupt regime shifts include the critical slowing down as a transition point is approached, rising variance and the lag-1 autocorrelation function, increased skewness of the steady-state probability distribution and the ratio of two mean first passage times for the exits from the stable steady states as the bifurcation point is approached. Noise-induced regime shifts are also possible for which the vicinity of the bifurcation point is not essential. In this paper, we review examples of regime shifts in natural systems and the associated early signatures. We further discuss how such approaches provide useful insights on a cell biological process involving the fold-bifurcation.

  5. Shear Capacity as Prognostic of Nocturnal Boundary Layer Regimes

    Science.gov (United States)

    van Hooijdonk, Ivo; Donda, Judith; Bosveld, Fred; Moene, Arnold; Clercx, Herman; van de Wiel, Bas

    2015-04-01

    After sunset the surface temperature can drop rapidly in some nights and may lead to ground frost. This sudden drop is closely related to the occurrence of fundamentally different behaviour of turbulence in the nocturnal boundary layer. Recent theoretical findings predict the appearance of two different regimes: the continuously turbulent (weakly stable) boundary layer and the relatively 'quiet' (very stable) boundary layer. Field observations from a large number of nights (approx. 4500 in total) are analysed using an ensemble averaging technique. The observations support the existence of these two fundamentally different regimes: weakly stable (turbulent) nights rapidly reach a steady state (within 2-3 hours). In contrast, very stable nights reach a steady state much later after a transition period (2-6 hours). During this period turbulence is weak and non-stationary. To characterise the regime a new parameter is introduced: the Shear Capacity. This parameter compares the actual shear after sunset with the minimum shear needed to sustain continuous turbulence. In turn, the minimum shear is dictated by the heat flux demand at the surface (net radiative cooling), so that the Shear Capacity combines flow information with knowledge on the boundary condition. It is shown that the Shear Capacity enables prediction of the flow regimes. The prognostic strength of this non-dimensional parameter appears to outperform the traditional ones like z/L and Ri as regime indicator.

  6. THE IMPACT OF THE GLOBAL NUCLEAR SAFETY REGIME IN BRAZIL

    International Nuclear Information System (INIS)

    A turning point of the world nuclear industry with respect to safety occurred due to the accident at Chernobyl, in 1986. A side from the tragic personal losses and the enormous financial damage, the Chernobyl accident has literally demonstrated that ''a nuclear accident anywhere is an accident everywhere''. The impact was felt immediately by the nuclear industry, with plant cancellations (e.g. Austria), elimination of national programs (e.g. Italy) and general construction delays. However, the reaction of the nuclear industry was equally immediate, which led to the proposal and establishment of a Global Nuclear Safety Regime. This regime is composed of biding international safety conventions, globally accepted safety standard, and a voluntary peer review system. In a previous work, the author has presented in detail the components of this Regime, and briefly discussed its impact in the Brazilian nuclear power organizations, including the Regulatory Body. This work, on the opposite, briefly reviews the Global Nuclear Safety Regime, and concentrates in detail in the discussion of its impact in Brazil, showing how it has produced some changes, and where the peer pressure regime has failed to produce real results

  7. Early Regimes of Water Capillary Flow in Slit Silica Nanochannels

    DEFF Research Database (Denmark)

    Oyarzua, Elton; Walther, Jens Honore; Mejia, Andres;

    2015-01-01

    Molecular dynamics simulations are conducted to investigate the initial stages of spontaneous imbibitionof water in slit silica nanochannels surrounded by air. An analysis is performed for the effects of nanoscopicconfinement, initial conditions of liquid uptake and air pressurization on the dyna......Molecular dynamics simulations are conducted to investigate the initial stages of spontaneous imbibitionof water in slit silica nanochannels surrounded by air. An analysis is performed for the effects of nanoscopicconfinement, initial conditions of liquid uptake and air pressurization...... on the dynamics of capillaryfilling. The results indicate that the nanoscale imbibition process is divided into three main flow regimes:an initial regime where the capillary force is balanced only by the inertial drag and characterized by aconstant velocity and a plug flow profile. In this regime, the meniscus...... formation process plays a centralrole in the imbibition rate. Thereafter, a transitional regime takes place, in which, the force balance hassignificant contributions from both inertia and viscous friction. Subsequently, a regime wherein viscousforces dominate the capillary force balance is attained. Flow...

  8. Hydrological minimal model for fire regime assessment in Mediterranean ecosystem

    Science.gov (United States)

    Ursino, N.; Rulli, M. C.

    2012-04-01

    A new model for Mediterranean forest fire regime assessment is presented and discussed. The model is based on the experimental evidence that fire is due to both hydrological and ecological processes and the relative role of fuel load versus fuel moisture is an important driver in fire ecology. Diverse scenarios are analyzed where either the hydrological forcing or the feedback between fire and hydrological characterization of the site is changed. The model outcome demonstrates that the two way interaction between hydrological processes, biology and fire regime drives the ecosystem toward a typical fire regime that may be altered either by an evolution of the biological characterization of the site or by a change of the hydrological forcing. This tenet implies that not every fire regime is compatible with the ecohydrological characterization of the site under study. This means that natural (non antropogenic) fire cannot be modeled as an arbitrary external forcing because the coupled hydrological and biological processes determines its statistical characterization, and conversely, the fire regime affects the soil moisture availability and the outcome of different species competition under possible water stress. The new modelling approach presented here, when provided by a proper model parameterization, can advance the capability in predicting and managing fires in ecosystems influenced by climate and land use changes.

  9. Soil magnetic susceptibility reflects soil moisture regimes and the adaptability of tree species to these regimes

    Science.gov (United States)

    Wang, J.-S.; Grimley, D.A.; Xu, C.; Dawson, J.O.

    2008-01-01

    Flooded, saturated or poorly drained soils are frequently anaerobic, leading to dissolution of the strongly magnetic minerals, magnetite and maghemite, and a corresponding decrease in soil magnetic susceptibility (MS). In this study of five temperate deciduous forests in east-central Illinois, USA, mean surface soil MS was significantly higher adjacent to upland tree species (31 ?? 10-5 SI) than adjacent to floodplain or lowland tree species (17 ?? 10-5 SI), when comparing regional soils with similar parent material of loessal silt. Although the sites differ in average soil MS for each tree species, the relative order of soil MS means for associated tree species at different locations is similar. Lowland tree species, Celtis occidentalis L., Ulmus americana L., Acer saccharinum L., Carya laciniosa (Michx. f.) Loud., and Fraxinus pennsylvanica Marsh. were associated with the lowest measured soil MS mean values overall and at each site. Tree species' flood tolerance rankings increased significantly, as soil MS values declined, the published rankings having significant correlations with soil MS values for the same species groups. The three published classifications of tree species' flood tolerance were significantly correlated with associated soil MS values at all sites, but most strongly at Allerton Park, the site with the widest range of soil drainage classes and MS values. Using soil MS measurements in forests with soil parent material containing similar initial levels of strongly magnetic minerals can provide a simple, rapid and quantitative method to classify soils according to hydric regimes, including dry conditions, and associated plant composition. Soil MS values thus have the capacity to quantify the continuum of hydric tolerances of tree species and guide tree species selection for reforestation. ?? 2007 Elsevier B.V. All rights reserved.

  10. A Markov Switching Regime Model of Malaysia Property Cycle

    Directory of Open Access Journals (Sweden)

    Abdul M. Beksin

    2011-01-01

    Full Text Available Problem statement: Non-linear models such as the Markov Switching regime (MS method of modelling business cycles, in principle can be used to model property cyle. Approach: The MS model can distinguish property cycle in recession and expansion phases and is sufficiently flexible to allow different relationships to apply over these phases. In this study, the Malaysian property cycle is modelled using a MS model. Results: This technique can be used to simultaneously estimate the data generating process of real GDP growth and classify each observation into one of two regimes (i.e., low-growth and high-growth regimes. Conclusions: This finding has important policy implications, since the yield spread was used to generate the time-varying probabilities of the MS model as well as the recession probabilities of the logit model. In other words, a strong relationship exists between interest rates and the business cycle, where interest rates lead the business cycle.

  11. Inhomogeneous stationary and oscillatory regimes in coupled chaotic oscillators.

    Science.gov (United States)

    Liu, Weiqing; Volkov, Evgeny; Xiao, Jinghua; Zou, Wei; Zhan, Meng; Yang, Junzhong

    2012-09-01

    The dynamics of linearly coupled identical Lorenz and Pikovsky-Rabinovich oscillators are explored numerically and theoretically. We concentrate on the study of inhomogeneous stable steady states ("oscillation death (OD)" phenomenon) and accompanying periodic and chaotic regimes that emerge at an appropriate choice of the coupling matrix. The parameters, for which OD occurs, are determined by stability analysis of the chosen steady state. Three model-specific types of transitions to and from OD are observed: (1) a sharp transition to OD from a nonsymmetric chaotic attractor containing random intervals of synchronous chaos; (2) transition to OD from the symmetry-breaking chaotic regime created by negative coupling; (3) supercritical bifurcation of OD into inhomogeneous limit cycles and further evolution of the system to inhomogeneous chaotic regimes that coexist with complete synchronous chaos. These results may fill a gap in the understanding of the mechanism of OD in coupled chaotic systems.

  12. Quantum SASE Regime for X-Ray FEL

    CERN Document Server

    Avetissian, H K

    2005-01-01

    For the X-ray FEL if the amplifying photon energy is larger or comparable to resonance widths caused by an electron beam spreads or by the finite interaction length then the quantum effects may play a significant role [1] and the generation process shifts from the classical to the quantum regime. The recent advancement of high brightness particle and laser beams technology makes achievable the fulfillment of these conditions in the scheme of X-ray Backscatter Compton laser. In this work we consider in general the SASE X-ray FEL in the quantum regime of amplification arising from the self-consistent set of the Maxwell and relativistic quantum kinetic equations. It is shown a considerable increase in start-up and narrowing of the spectrum of the SASE power for amplifying X-ray frequencies compared with the classical SASE regime.

  13. Dynamo regimes and transitions in the VKS experiment

    CERN Document Server

    Berhanu, M; Boisson, J; Gallet, B; Gissinger, C; Fauve, S; Mordant, N; Pétrélis, F; Bourgoin, M; Odier, P; Pinton, J -F; Plihon, N; Aumaître, S; Chiffaudel, A; Daviaud, F; Dubrulle, B; Pirat, C

    2015-01-01

    The Von K{\\'a}rm{\\'a}n Sodium experiment yields a variety of dynamo regimes, when asymmetry is imparted to the flow by rotating impellers at different speed F1 and F2. We show that as the intensity of forcing, measured as F1 + F2, is increased, the transition to a self-sustained magnetic field is always observed via a supercritical bifurcation to a stationary state. For some values of the asymmetry parameter $\\\\theta$ = (F1--F2)/(F1+F2), time dependent dynamo regimes develop. They are observed either when the forcing is increased for a given value of asymmetry, or when the amount of asymmetry is varied at sufficiently high forcing. Two qualitatively different transitions between oscillatory and stationary regimes are reported, involving or not a strong divergence of the period of oscillations. These transitions can be interpreted using a low dimensional model based on the interactions of two dynamo modes.

  14. Challenges in Finding AGNs in the Low Luminosity Regime

    Science.gov (United States)

    Satyapal, Shobita; Abel, Nick; Secrest, Nathan; Singh, Amrit; Ellison, Sara

    2016-08-01

    Low luminosity AGNs are an important component of the AGN population. They are often found in the lowest mass galaxies or galaxies that lack classical bulges, a demographic that places important constraints to models of supermassive black hole seed formation and merger-free models of AGN fueling. The detection of AGNs in this low luminosity regime is challenging both because star formation in the host galaxy can dominate the optical spectrum and gas and dust can obscure the central engine at both optical and X-ray wavelengths. Thus while mid-infrared color selection and X-ray observations at energies <10 keV are often powerful tools in uncovering optically unidentified AGNs at higher luminosities, this is not the case in the low luminosity regime. In this talk, I will review the effectiveness of uncovering AGNs in the low luminosity regime using multiwavength investigations, with a focus on infrared spectroscopic signatures.

  15. Nonlinear-optical frequency-doubling metareflector: pulsed regime

    Science.gov (United States)

    Popov, A. K.; Myslivets, S. A.

    2016-01-01

    The properties of backward-wave second-harmonic metareflector operating in pulse regime are investigated. It is made of metamaterial which enables phase matching of contra-propagating fundamental and second-harmonic waves. References are given to the works that prove such a possibility. Physical principles underlying differences in the proposed and standard settings as well as between continuous-wave and pulsed regimes are discussed. Pulsed regime is more practicable and has a broader scope of applications. A set of partial differential equations which describe such a reflector with the account for losses are solved numerically. It is shown that unlike second-harmonic generation in standard settings, contra-propagating pulse of second harmonic may become much longer than the incident fundamental one and the difference grows with decrease in the input pulse length as compared to thickness of the metaslab. The revealed properties are important for applications and may manifest themselves beyond the optical wavelength range.

  16. Adelie penguin foraging location predicted by tidal regime switching.

    Directory of Open Access Journals (Sweden)

    Matthew J Oliver

    Full Text Available Penguin foraging and breeding success depend on broad-scale environmental and local-scale hydrographic features of their habitat. We investigated the effect of local tidal currents on a population of Adélie penguins on Humble Is., Antarctica. We used satellite-tagged penguins, an autonomous underwater vehicle, and historical tidal records to model of penguin foraging locations over ten seasons. The bearing of tidal currents did not oscillate daily, but rather between diurnal and semidiurnal tidal regimes. Adélie penguins foraging locations changed in response to tidal regime switching, and not to daily tidal patterns. The hydrography and foraging patterns of Adélie penguins during these switching tidal regimes suggest that they are responding to changing prey availability, as they are concentrated and dispersed in nearby Palmer Deep by variable tidal forcing on weekly timescales, providing a link between local currents and the ecology of this predator.

  17. The political constitution of the EU citizen rights regime

    DEFF Research Database (Denmark)

    Olsen, Tore Vincents

    2011-01-01

    Reactions to decisions by the European Court of Justice (ECJ) demonstrate that the political institutions in the Union should take responsibility for the development of the structure of the European Union's (EU) citizen rights regime. This article analyses different political views on the EU...... citizen rights regime. It argues that the disagreement between them is largely a disagreement between ‘reasonable views’. The disagreement is mainly based on different views about the levels (European, national) at which individuals are to be seen as equals and about the contribution of different...... communities and institutions to the good life of citizens, both individually and collectively. Taking the contestation between the different views seriously, the article argues in favour of political constitutionalism, according to which the development of the EU citizen rights regime is the responsibility...

  18. Modeling whistler wave generation regimes in magnetospheric cyclotron maser

    Directory of Open Access Journals (Sweden)

    D. L. Pasmanik

    2004-11-01

    Full Text Available Numerical analysis of the model for cyclotron instability in the Earth's magnetosphere is performed. This model, based on the self-consistent set of equations of quasi-linear plasma theory, describes different regimes of wave generation and related energetic particle precipitation. As the source of free energy the injection of energetic electrons with transverse anisotropic distribution function to the interaction region is considered. A parametric study of the model is performed. The main attention is paid to the analysis of generation regimes for different characteristics of energetic electron source, such as the shape of pitch angle distributions and its intensity. Two mechanisms of removal of energetic electrons from a generation region are considered, one is due to the particle precipitation through the loss cone and another one is related to the magnetic drift of energetic particles.

    It was confirmed that two main regimes occur in this system in the presence of a constant particle source, in the case of precipitation losses. At small source intensity relaxation oscillations were found, whose parameters are in good agreement with simplified analytical theory developed earlier. At a larger source intensity, transition to a periodic generation occurs. In the case of drift losses the regime of self-sustained periodic generation regime is realized for source intensity higher than some threshold. The dependencies of repetition period and dynamic spectrum shape on the source parameters were studied in detail. In addition to simple periodic regimes, those with more complex spectral forms were found. In particular, alteration of spikes with different spectral shape can take place. It was also shown that quasi-stationary generation at the low-frequency band can coexist with periodic modulation at higher frequencies.

    On the basis of the results obtained, the model for explanation of

  19. How will climate change modify river flow regimes in Europe?

    Directory of Open Access Journals (Sweden)

    C. Schneider

    2013-01-01

    Full Text Available Worldwide, flow regimes are being modified by various anthropogenic impacts and climate change induces an additional risk. Rising temperatures, declining snow cover and changing precipitation patterns will interact differently at different locations. Consequently, in distinct climate zones, unequal consequences can be expected in matters of water stress, flood risk, water quality, and food security. In particular, river ecosystems and their vital ecosystem services will be compromised as their species richness and composition have evolved over long time under natural flow conditions. This study aims at evaluating the exclusive impacts of climate change on river flow regimes in Europe. Various flow characteristics are taken into consideration and diverse dynamics are identified for each distinct climate zone in Europe. In order to simulate present-day natural flow regimes and future flow regimes under climate change, the global hydrology model WaterGAP3 is applied. All calculations for current and future conditions (2050s are carried out on a 5' × 5' European grid. To address uncertainty, bias-corrected climate forcing data of three different global climate models are used to drive WaterGAP3. Finally, the hydrological alterations of different flow characteristics are quantified by the Indicators of Hydrological Alteration approach. Results of our analysis indicate that on the European scale, climate change can be expected to modify flow regimes remarkably. This is especially the case in the Mediterranean (due to drier conditions with reduced precipitation across the year and in the boreal climate zone (due to reduced snowmelt, increased precipitation, and strong temperature rises. In the temperate climate zone, impacts increase from oceanic to continental. Regarding single flow characteristics, strongest impacts on timing were found for the boreal climate zone. This applies for both high and low flows. Flow magnitudes, in turn, will be

  20. Terahertz Quantum Plasmonics of Nanoslot Antennas in Nonlinear Regime.

    Science.gov (United States)

    Kim, Joon-Yeon; Kang, Bong Joo; Park, Joohyun; Bahk, Young-Mi; Kim, Won Tae; Rhie, Jiyeah; Jeon, Hyeongtag; Rotermund, Fabian; Kim, Dai-Sik

    2015-10-14

    Quantum tunneling in plasmonic nanostructures has presented an interesting aspect of incorporating quantum mechanics into classical optics. However, the study has been limited to the subnanometer gap regime. Here, we newly extend quantum plasmonics to gap widths well over 1 nm by taking advantage of the low-frequency terahertz regime. Enhanced electric fields of up to 5 V/nm induce tunneling of electrons in different arrays of ring-shaped nanoslot antennas of gap widths from 1.5 to 10 nm, which lead to a significant nonlinear transmission decrease. These observations are consistent with theoretical calculations considering terahertz-funneling-induced electron tunneling across the gap.

  1. Selection Criteria in Regime Switching Conditional Volatility Models

    Directory of Open Access Journals (Sweden)

    Thomas Chuffart

    2015-05-01

    Full Text Available A large number of nonlinear conditional heteroskedastic models have been proposed in the literature. Model selection is crucial to any statistical data analysis. In this article, we investigate whether the most commonly used selection criteria lead to choice of the right specification in a regime switching framework. We focus on two types of models: the Logistic Smooth Transition GARCH and the Markov-Switching GARCH models. Simulation experiments reveal that information criteria and loss functions can lead to misspecification ; BIC sometimes indicates the wrong regime switching framework. Depending on the Data Generating Process used in the experiments, great care is needed when choosing a criterion.

  2. Phase contrast and operation regimes in multifrequency atomic force microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Sergio [Departament de Disseny i Programació de Sistemes Electrònics, UPC—Universitat Politècnica de Catalunya Av. Bases, 61, 08242 Manresa (Barcelona) (Spain)

    2014-04-07

    In amplitude modulation atomic force microscopy the attractive and the repulsive force regimes induce phase shifts above and below 90°, respectively. In the more recent multifrequency approach, however, multiple operation regimes have been reported and the theory should be revisited. Here, a theory of phase contrast in multifrequency atomic force microscopy is developed and discussed in terms of energy transfer between modes, energy dissipation and the kinetic energy and energy transfer associated with externally driven harmonics. The single frequency virial that controls the phase shift might undergo transitions in sign while the average force (modal virial) remains positive (negative)

  3. Dynamic two state stochastic models for ecological regime shifts

    DEFF Research Database (Denmark)

    Møller, Jan Kloppenborg; Carstensen, Niels Jacob; Madsen, Henrik;

    2009-01-01

    of the model illustrates that hysteresis effect and regime shifts can be obtained for a limited range of parameter values only. The effect of multiplicative noise components entering at different levels of the model is presented and discussed. Including noise leads to very different results on the stability...... of regimes, depending on how the noise propagates through the system. The dynamical properties of a system should therefore be described through propagation of the state distributions rather than the state means and consequently, stochastic models should be compared in a probabilistic framework....

  4. PREDICTION OF FLOW REGIMES IN SPOUT-FLUIDIZED BEDS

    Institute of Scientific and Technical Information of China (English)

    Jiyu Zhang; Fengxiang Tang

    2006-01-01

    Five main flow regimes in spout-fluidized bed were identified in this study, namely, fixed bed, spout with aeration, spout-fluidization, jet in fluidized bed and slugging, together with their corresponding major frequencies translated from pressure signals. The empirical equation A=aBb, in which A=Fr* /(H/Di) and B=(Fr*/(H/D))/(μg/μmf) are respectively the spout-geometry and spout-geometry-fluidization dimensionless numbers, was proposed to distinguish these flow regimes.

  5. NAZI REGIME IN THE PERIODICAL A NOTÍ­CIA.

    Directory of Open Access Journals (Sweden)

    Bruna Luíza Barcellos

    2009-08-01

    Full Text Available The periodical A Notícia, of Joinville, city colonized for Germans, supported the nazi regime since the ascension of Adolf Hitler to the power. Between 1932 and 1944, some editions had printed the figure of Hitler and the nazi symbol, beyond dither messages to that regime. Based in the Análise de conteúdo (BARDIN, 1977, this article searchs to understand the representation made for the periodical A Notícia on this historical landmark, in other words, bring to the light the consequences of a part of occured world-wide history in catarinense territory.

  6. Development and current trends in the international nonproliferation regime

    International Nuclear Information System (INIS)

    The IAEA and its safeguards system is placed into a historical perspective. A personal perspective on the nonproliferation regime and on the Agency's role in it is then presented. This is done initially by discussing some of the landmark events in the history of the nonproliferation regime. Subsequently some of the history of arms control agreements and of the role of the IAEA are noted. Then political motivations of state and ways the Agency has an impact in the political nonproliferation sphere are addressed

  7. Measurement of flow in supercritical flow regime using cutthroat flumes

    Indian Academy of Sciences (India)

    Shrikant A Tekade; Avinash D Vasudeo; Aniruddha D Ghare; Ramesh N Ingle

    2016-02-01

    Cutthroat flume is commonly used for measurement of subcritical flow in open channel because of its simplicity and ease of construction. No experimental data is available in literature for measurement of flow in supercritical regime using cutthroat flume. The present paper finds the feasibility of cutthroat flume as a measurement device for flow in supercritical regime. Experimental data are generated to develop the relation between discharge and observed head at a specified location on upstream of throat section. Regression analysis for discharge and head indicated a good correlation. Based on all the experimental data generated, a relationship between discharge and head is proposed.

  8. Explicit Mapping of Acoustic Regimes For Wind Instruments

    CERN Document Server

    Missoum, Samy; Doc, Jean-Baptiste

    2014-01-01

    This paper proposes a methodology to map the various acoustic regimes of wind instruments. The maps can be generated in a multi-dimensional space consisting of design, control parameters, and initial conditions. The bound- aries of the maps are obtained explicitly in terms of the parameters using a support vector machine (SVM) classifier as well as a dedicated adaptive sam- pling scheme. The approach is demonstrated on a simplified clarinet model for which several maps are generated based on different criteria. Examples of computation of the probability of occurrence of a specific acoustic regime are also provided. In addition, the approach is demonstrated on a design optimization example for optimal intonation.

  9. Using Clustering to Establish Climate Regimes from PCM Output

    Science.gov (United States)

    Oglesby, Robert; Arnold, James E. (Technical Monitor); Hoffman, Forrest; Hargrove, W. W.; Erickson, D.

    2002-01-01

    A multivariate statistical clustering technique--based on the k-means algorithm of Hartigan has been used to extract patterns of climatological significance from 200 years of general circulation model (GCM) output. Originally developed and implemented on a Beowulf-style parallel computer constructed by Hoffman and Hargrove from surplus commodity desktop PCs, the high performance parallel clustering algorithm was previously applied to the derivation of ecoregions from map stacks of 9 and 25 geophysical conditions or variables for the conterminous U.S. at a resolution of 1 sq km. Now applied both across space and through time, the clustering technique yields temporally-varying climate regimes predicted by transient runs of the Parallel Climate Model (PCM). Using a business-as-usual (BAU) scenario and clustering four fields of significance to the global water cycle (surface temperature, precipitation, soil moisture, and snow depth) from 1871 through 2098, the authors' analysis shows an increase in spatial area occupied by the cluster or climate regime which typifies desert regions (i.e., an increase in desertification) and a decrease in the spatial area occupied by the climate regime typifying winter-time high latitude perma-frost regions. The patterns of cluster changes have been analyzed to understand the predicted variability in the water cycle on global and continental scales. In addition, representative climate regimes were determined by taking three 10-year averages of the fields 100 years apart for northern hemisphere winter (December, January, and February) and summer (June, July, and August). The result is global maps of typical seasonal climate regimes for 100 years in the past, for the present, and for 100 years into the future. Using three-dimensional data or phase space representations of these climate regimes (i.e., the cluster centroids), the authors demonstrate the portion of this phase space occupied by the land surface at all points in space and time

  10. Using Clustering to Establish Climate Regimes from PCM Output

    Science.gov (United States)

    Hoffman, F.; Oglesby, R.; Hargrove, W. W.; Erickson, D.

    2002-12-01

    A multivariate statistical clustering technique--based on the k-means algorithm of Hartigan--has been used to extract patterns of climatological significance from 200 years of general circulation model (GCM) output. Originally developed and implemented on a Beowulf-style parallel computer constructed by Hoffman and Hargrove from surplus commodity desktop PCs, the high performance parallel clustering algorithm was previously applied to the derivation of ecoregions from map stacks of 9 and 25 geophysical conditions or variables for the conterminous U.S. at a resolution of 1 sq km. Now applied both across space and through time, the clustering technique yields temporally-varying climate regimes predicted by transient runs of the Parallel Climate Model (PCM). Using a business-as-usual (BAU) scenario and clustering four fields of significance to the global water cycle (surface temperature, precipitation, soil moisture, and snow depth) from 1871 through 2098, the authors' analysis shows an increase in spatial area occupied by the cluster or climate regime which typifies desert regions (i.e., an increase in desertification) and a decrease in the spatial area occupied by the climate regime typifying winter-time high latitude perma-frost regions. The patterns of cluster changes have been analyzed to understand the predicted variability in the water cycle on global and continental scales. In addition, representative climate regimes were determined by taking three 10-year averages of the fields 100 years apart for northern hemisphere winter (December, January, and February) and summer (June, July, and August). The result is global maps of typical seasonal climate regimes for 100 years in the past, for the present, and for 100 years into the future. Using three-dimensional data or phase space representations of these climate regimes (i.e., the cluster centroids), the authors demonstrate the portion of this phase space occupied by the land surface at all points in space and

  11. Predicting weather regime transitions in Northern Hemisphere datasets

    Energy Technology Data Exchange (ETDEWEB)

    Kondrashov, D. [University of California, Department of Atmospheric and Oceanic Sciences and Institute of Geophysics and Planetary Physics, Los Angeles, CA (United States); Shen, J. [UCLA, Department of Statistics, Los Angeles, CA (United States); Berk, R. [UCLA, Department of Statistics, Los Angeles, CA (United States); University of Pennsylvania, Department of Criminology, Philadelphia, PA (United States); D' Andrea, F.; Ghil, M. [Ecole Normale Superieure, Departement Terre-Atmosphere-Ocean and Laboratoire de Meteorologie Dynamique (CNRS and IPSL), Paris Cedex 05 (France)

    2007-10-15

    A statistical learning method called random forests is applied to the prediction of transitions between weather regimes of wintertime Northern Hemisphere (NH) atmospheric low-frequency variability. A dataset composed of 55 winters of NH 700-mb geopotential height anomalies is used in the present study. A mixture model finds that the three Gaussian components that were statistically significant in earlier work are robust; they are the Pacific-North American (PNA) regime, its approximate reverse (the reverse PNA, or RNA), and the blocked phase of the North Atlantic Oscillation (BNAO). The most significant and robust transitions in the Markov chain generated by these regimes are PNA {yields} BNAO, PNA {yields} RNA and BNAO {yields} PNA. The break of a regime and subsequent onset of another one is forecast for these three transitions. Taking the relative costs of false positives and false negatives into account, the random-forests method shows useful forecasting skill. The calculations are carried out in the phase space spanned by a few leading empirical orthogonal functions of dataset variability. Plots of estimated response functions to a given predictor confirm the crucial influence of the exit angle on a preferred transition path. This result points to the dynamic origin of the transitions. (orig.)

  12. Is the Economic Crisis Challenging the Prevailing Gender Regime?

    DEFF Research Database (Denmark)

    Leschke, Janine; Jepsen, Maria

    2014-01-01

    This paper addresses the question of whether the current economic and financial crisis is challenging the prevailing gender-equality model in four European countries: Denmark, Germany, Slovakia, and the United Kingdom. After situating the countries in relation to the underlying gender regime...

  13. Detection and Assessment of Ecosystem Regime Shifts from Fisher Information

    Directory of Open Access Journals (Sweden)

    B. Roy Frieden

    2008-06-01

    Full Text Available Ecosystem regime shifts, which are long-term system reorganizations, have profound implications for sustainability. There is a great need for indicators of regime shifts, particularly methods that are applicable to data from real systems. We have developed a form of Fisher information that measures dynamic order in complex systems. Here we propose the use of Fisher information as a means of: (1 detecting dynamic regime shifts in ecosystems, and (2 assessing the quality of the shift in terms of intensity and pervasiveness. Intensity is reflected by the degree of change in dynamic order, as determined by Fisher information, and pervasiveness is a reflection of how many observable variables are affected by the change. We present a new robust methodology to calculate Fisher information from time series field data. We demonstrate the use of Fisher information to detect regime shifts on a model for a shallow lake. Next, we use Fisher information to analyze marine ecosystem response to physical changes using real time-series data of a coastal marine ecosystem, the North Pacific Ocean.

  14. Exploiting synergies between nonproliferation verification regimes: A pragmatic approach

    International Nuclear Information System (INIS)

    This paper considers the potential for expanding interaction and exploiting synergies between different multilateral disarmament and nonproliferation regimes. It concludes that although there are political barriers to high-level and pervasive synergization, there are opportunities for pragmatic, functional steps to be taken as a way of building confidence and experience. (author)

  15. Dynamic Financial Constraints: Distinguishing Mechanism Design from Exogenously Incomplete Regimes.

    Science.gov (United States)

    Karaivanov, Alexander; Townsend, Robert M

    2014-05-01

    We formulate and solve a range of dynamic models of constrained credit/insurance that allow for moral hazard and limited commitment. We compare them to full insurance and exogenously incomplete financial regimes (autarky, saving only, borrowing and lending in a single asset). We develop computational methods based on mechanism design, linear programming, and maximum likelihood to estimate, compare, and statistically test these alternative dynamic models with financial/information constraints. Our methods can use both cross-sectional and panel data and allow for measurement error and unobserved heterogeneity. We estimate the models using data on Thai households running small businesses from two separate samples. We find that in the rural sample, the exogenously incomplete saving only and borrowing regimes provide the best fit using data on consumption, business assets, investment, and income. Family and other networks help consumption smoothing there, as in a moral hazard constrained regime. In contrast, in urban areas, we find mechanism design financial/information regimes that are decidedly less constrained, with the moral hazard model fitting best combined business and consumption data. We perform numerous robustness checks in both the Thai data and in Monte Carlo simulations and compare our maximum likelihood criterion with results from other metrics and data not used in the estimation. A prototypical counterfactual policy evaluation exercise using the estimation results is also featured.

  16. Just for Fun? The Emotional Regime of Experiential Consumption

    DEFF Research Database (Denmark)

    Jantzen, Christian; Fitchett, James; Østergaard, Per;

    2012-01-01

    Experiential consumption emphasizes emotional and hedonic qualities in the marketplace stressing the importance of experiences for ‘the good life’ and positioning consumption as a legitimate way to generate interesting and relevant experiences. The concept of emotional regimes (Reddy, 2001) is used...

  17. Process-based humidity control regime for greenhouse crops

    NARCIS (Netherlands)

    Korner, O.; Challa, H.

    2003-01-01

    Modern greenhouses in The Netherlands are designed for efficient use of energy. Climate control traditionally aims at optimal crop performance. However, energy saving is a major issue for the development of new temperature regimes. Temperature integration (TI) results in fluctuating and often high r

  18. Operating regimes of signaling cycles: statics, dynamics, and noise filtering.

    Directory of Open Access Journals (Sweden)

    Carlos Gomez-Uribe

    2007-12-01

    Full Text Available A ubiquitous building block of signaling pathways is a cycle of covalent modification (e.g., phosphorylation and dephosphorylation in MAPK cascades. Our paper explores the kind of information processing and filtering that can be accomplished by this simple biochemical circuit. Signaling cycles are particularly known for exhibiting a highly sigmoidal (ultrasensitive input-output characteristic in a certain steady-state regime. Here, we systematically study the cycle's steady-state behavior and its response to time-varying stimuli. We demonstrate that the cycle can actually operate in four different regimes, each with its specific input-output characteristics. These results are obtained using the total quasi-steady-state approximation, which is more generally valid than the typically used Michaelis-Menten approximation for enzymatic reactions. We invoke experimental data that suggest the possibility of signaling cycles operating in one of the new regimes. We then consider the cycle's dynamic behavior, which has so far been relatively neglected. We demonstrate that the intrinsic architecture of the cycles makes them act--in all four regimes--as tunable low-pass filters, filtering out high-frequency fluctuations or noise in signals and environmental cues. Moreover, the cutoff frequency can be adjusted by the cell. Numerical simulations show that our analytical results hold well even for noise of large amplitude. We suggest that noise filtering and tunability make signaling cycles versatile components of more elaborate cell-signaling pathways.

  19. Accessing Imagined Communities and Reinscribing Regimes of Truth

    Science.gov (United States)

    Carroll, Sherrie; Motha, Suhanthie; Price, Jeremy N.

    2008-01-01

    In this article, we explore the complex and nebulous terrain between two theoretical concepts, imagined communities (Norton, 2000, 2001), that is, individuals' imagined affiliations with certain groups, and regimes of truth (Foucault, 1980), dominant images inscribed and reinscribed into individual consciousness until they become normative. Using…

  20. Regimes of flow induced vibration for tandem, tethered cylinders

    Science.gov (United States)

    Nave, Gary; Stremler, Mark

    2015-11-01

    In the wake of a bluff body, there are a number of dynamic response regimes that exist for a trailing bluff body depending on spacing, structural restoring forces, and the mass-damping parameter m* ζ . For tandem cylinders with low values of m* ζ , two such regimes of motion are Gap Flow Switching and Wake Induced Vibration. In this study, we consider the dynamics of a single degree-of-freedom rigid cylinder in the wake of another in these regimes for a variety of center-to-center cylinder spacings (3-5 diameters) and Reynolds numbers (4,000-11,000). The system consists of a trailing cylinder constrained to a circular arc around a fixed leading cylinder, which, for small angle displacements, bears a close resemblance to the transversely oscillating cylinders found more commonly in existing literature. From experiments on this system, we compare and contrast the dynamic response within these two regimes. Our results show sustained oscillations in the absence of a structural restoring force in all cases, providing experimental support for the wake stiffness assumption, which is based on the mean lift toward the center line of flow.

  1. Exploring the epsilon regime with twisted mass fermions

    CERN Document Server

    Jansen, K; Shindler, A; Urbach, C; Wenger, U

    2007-01-01

    In this proceeding contribution we report on a first study in order to explore the so called epsilon regime with Wilson twisted mass (Wtm) fermions. To show the potential of this approach we give a preliminary determination of the chiral condensate.

  2. Dynamic Financial Constraints: Distinguishing Mechanism Design from Exogenously Incomplete Regimes.

    Science.gov (United States)

    Karaivanov, Alexander; Townsend, Robert M

    2014-05-01

    We formulate and solve a range of dynamic models of constrained credit/insurance that allow for moral hazard and limited commitment. We compare them to full insurance and exogenously incomplete financial regimes (autarky, saving only, borrowing and lending in a single asset). We develop computational methods based on mechanism design, linear programming, and maximum likelihood to estimate, compare, and statistically test these alternative dynamic models with financial/information constraints. Our methods can use both cross-sectional and panel data and allow for measurement error and unobserved heterogeneity. We estimate the models using data on Thai households running small businesses from two separate samples. We find that in the rural sample, the exogenously incomplete saving only and borrowing regimes provide the best fit using data on consumption, business assets, investment, and income. Family and other networks help consumption smoothing there, as in a moral hazard constrained regime. In contrast, in urban areas, we find mechanism design financial/information regimes that are decidedly less constrained, with the moral hazard model fitting best combined business and consumption data. We perform numerous robustness checks in both the Thai data and in Monte Carlo simulations and compare our maximum likelihood criterion with results from other metrics and data not used in the estimation. A prototypical counterfactual policy evaluation exercise using the estimation results is also featured. PMID:25246710

  3. Dynamic Financial Constraints: Distinguishing Mechanism Design from Exogenously Incomplete Regimes*

    Science.gov (United States)

    Karaivanov, Alexander; Townsend, Robert M.

    2014-01-01

    We formulate and solve a range of dynamic models of constrained credit/insurance that allow for moral hazard and limited commitment. We compare them to full insurance and exogenously incomplete financial regimes (autarky, saving only, borrowing and lending in a single asset). We develop computational methods based on mechanism design, linear programming, and maximum likelihood to estimate, compare, and statistically test these alternative dynamic models with financial/information constraints. Our methods can use both cross-sectional and panel data and allow for measurement error and unobserved heterogeneity. We estimate the models using data on Thai households running small businesses from two separate samples. We find that in the rural sample, the exogenously incomplete saving only and borrowing regimes provide the best fit using data on consumption, business assets, investment, and income. Family and other networks help consumption smoothing there, as in a moral hazard constrained regime. In contrast, in urban areas, we find mechanism design financial/information regimes that are decidedly less constrained, with the moral hazard model fitting best combined business and consumption data. We perform numerous robustness checks in both the Thai data and in Monte Carlo simulations and compare our maximum likelihood criterion with results from other metrics and data not used in the estimation. A prototypical counterfactual policy evaluation exercise using the estimation results is also featured. PMID:25246710

  4. Political Regime and Human Capital: A Cross-Country Analysis

    Science.gov (United States)

    Klomp, Jeroen; de Haan, Jakob

    2013-01-01

    We examine the relationship between different dimensions of the political regime in place and human capital using a two-step structural equation model. In the first step, we employ factor analysis on 16 human capital indicators to construct two new human capital measures (basic and advanced human capital). In the second step, we estimate the…

  5. Political regime and human capital : A cross-country analysis

    NARCIS (Netherlands)

    Klomp, J.G.; de Haan, J.

    2013-01-01

    We examine the relationship between different dimensions of the political regime in place and human capital using a two-step structural equation model. In the first step, we employ factor analysis on 16 human capital indicators to construct two new human capital measures (basic and advanced human ca

  6. Political regime and human capital: A cross-country analysis

    NARCIS (Netherlands)

    Klomp, J.G.; Haan, de J.

    2013-01-01

    We examine the relationship between different dimensions of the political regime in place and human capital using a two-step structural equation model. In the first step, we employ factor analysis on 16 human capital indicators to construct two new human capital measures (basic and advanced human ca

  7. Syria: The Consolidation of the Asad Regime, 1970-1975.

    Science.gov (United States)

    Olson, Robert W.

    1982-01-01

    Up to 1975-76, Syria's Hafiz al-Asad was successful in consolidating his power, securing the maintenance of his regime, and broadening his base of political power. His system started weakening in 1975 due to increased opposition stemming from Syria's intervention in the Lebanese civil war. (AM)

  8. Shearing box simulations in the Rayleigh unstable regime

    DEFF Research Database (Denmark)

    Nauman, Farrukh; Blackman, Eric G.

    2015-01-01

    We study the stability properties of Rayleigh unstable flows both in the purely hydrodynamic and magnetohydrodynamic (MHD) regimes for two different values of the shear $q=2.1, 4.2$ ($q = - d\\ln\\Omega / d\\ln r$) and compare it with the Keplerian case $q=1.5$. The Rayleigh stability criterion states...

  9. Welfare Attitudes and Social Expenditure: Do Regimes Shape Public Opinion?

    Science.gov (United States)

    Jakobsen, Tor Georg

    2011-01-01

    This article examines the link between regime types, social expenditure, and welfare attitudes. By employing data on 19 countries taken from the World Values Survey, the main aim is to see to what degree the institutions of a country affect the attitudes of its citizens. According to Esping-Andersen ("The three worlds of welfare capitalism".…

  10. Alternative pricing regimes in Ontario : exploring the impacts

    International Nuclear Information System (INIS)

    Legislative goals were recently established in Ontario to promote reliability and quality of electricity service and to ensure that distribution rates for customers remain reasonable. This presentation explored the effect of changing electricity pricing structures on residential customers in Ontario. This study investigated a period between May to December 2005, in the town of Milton, Ontario. Monthly demand was measured for each month, and monthly weighted averages were presented. Residents with electric heating were removed from the sample. Four pricing structure scenarios were examined: (1) flat rates; (2) time-of-use pricing regimes; (3) real time pricing regimes; and (4) critical peak pricing. Average monthly consumption rates for July and August for all 4 scenarios were presented. Results for time-of-use were compared to flat rates, which showed a slight increase in monthly costs. Real time average monthly electricity costs were significantly higher. Time-of-use costs increased by 57 per cent during the periods examined. Real time pricing regimes resulted in a 196 per cent rise in costs. It was concluded that more research must be done to explore the policy implications of pricing regimes and their effect on consumer behaviour. refs., tabs., figs

  11. Towards an Orderly Exit Regime in English Higher Education

    Science.gov (United States)

    Fisher, Andrew

    2016-01-01

    In a competitive market, the exit of those suppliers who cannot offer an attractive product at an attractive price is seen as desirable. However, the consequences for consumers when their own supplier leaves the market in an unplanned or disorderly way may be undesirable. Exit regimes exist in regulated markets to ensure that consumers are not…

  12. Oil and gas fiscal regimes of the western Canadian provinces

    International Nuclear Information System (INIS)

    This report compares the fiscal regimes in British Columbia, Alberta, Saskatchewan and Manitoba. During 1985-1988, federal and provincial governments have made numerous fiscal changes, many in response to the drop in world oil prices. The new fiscal policies generally have reflected governments' willingness to forego revenues in an effort to aid the oil and gas industry, with certain exemptions. Since 1988, changes have reflected trends of consolidation and less government willingness to forego revenues. A federal large corporations capital tax has been introduced, the natural gas exploration holiday in Alberta expired, new oil royalties were introduced, and changes were made in fiscal regimes to accomodate horizontal drilling in Saskatchewan and Manitoba. In this document, the existing corporate tax regime is described. A comparison of fiscal regimes must recognize the differing scale and nature of oil and gas operations among the 4 provinces, with Alberta accounting for 80-90% of Canada's oil and gas productions, while British Columbia, Saskatchewan and Manitoba are much smaller producers. The document describes Crown royalties and incentives and freehold taxes for each type of fuel (crude oil, natural gas, natural gas byproducts, nonconventional oil). 8 figs

  13. Nonlinear regimes in mean-field full-sphere dynamo

    CERN Document Server

    Pipin, V V

    2016-01-01

    The mean-field dynamo model is employed to study the non-linear dynamo regimes in a fully convective star of mass 0.3$M_{\\odot}$ rotating with period of 10 days. The differential rotation law was estimated using the mean-field hydrodynamic and heat transport equations. For the intermediate parameter of the turbulent magnetic Reynolds number, $Pm_{T}=3$ we found the oscillating dynamo regimes with period about 40Yr. The higher $Pm_{T}$ results to longer dynamo periods. The meridional circulation has one cell per hemisphere. It is counter-clockwise in the Northen hemisphere. The amplitude of the flow at the surface around 1 m/s. Tne models with regards for meridional circulation show the anti-symmetric relative to equator magnetic field. If the large-scale flows is fixed we find that the dynamo transits from axisymmetric to non-axisymmetric regimes for the overcritical parameter of the $\\alpha$effect. The change of dynamo regime occurs because of the non-axisymmetric non-linear $\\alpha$-effect. The situation pe...

  14. Microgravity Flow Regime Data: Buoyancy and Mixing Apparatus Effects

    Science.gov (United States)

    Shephard, Adam; Best, Frederick

    2010-01-01

    Zero-g two-phase flow data set qualification and flight experiment design have not been standardized and as a result, agreement among researchers has not been reached regarding what experimental conditions adequately approximate those of microgravity. The effects of buoyancy forces and mixing apparatus on the flow regime transitions are presented in this study. The gravity conditions onboard zero-g aircraft are at best 10-3 g which is used to approximate the 10-5 g conditions of microgravity, thus the buoyancy forces present on zero-g aircraft can become significantly large and unrepresentative of microgravity. When buoyancy forces approach those of surface tension forces, buoyancy induced coalescence occurs. When discussing flow regime transitions, these large buoyancy forces lead to flow regime transitions which otherwise would not occur. The buoyancy attributes of the two-phase flow data sets available in the literature are evaluated to determine which data sets exhibit buoyancy induced transitions. Upon comparison of the representative data sets, the affects of different mixing apparatus can be seen in the superficial velocity flow regime maps.

  15. Sputtering of Ge(001): transition between dynamic scaling regimes

    DEFF Research Database (Denmark)

    Smilgies, D.-M.; Eng, P.J.; Landemark, E.;

    1997-01-01

    We have studied the dynamic behavior of the Ge(001) surface during sputtering in situ and in real time using synchrotron X-ray diffraction. We find two dynamic regimes as a function of surface temperature and sputter current which are separated by a sharp transition. The boundary between these two...

  16. Search Regimes and the Industrial Dynamics of Science

    Science.gov (United States)

    Bonaccorsi, Andrea

    2008-01-01

    The article addresses the issue of dynamics of science, in particular of new sciences born in twentieth century and developed after the Second World War (information science, materials science, life science). The article develops the notion of search regime as an abstract characterization of dynamic patterns, based on three dimensions: the rate of…

  17. Regime shifts limit the predictability of land-system change

    DEFF Research Database (Denmark)

    Müller, Daniel; Sun, Zhanli; Vongvisouk, Thoumthone;

    2014-01-01

    (China, Laos, Vietnam and Indonesia). The results show how sudden events and gradual changes in underlying drivers caused rapid, surprising and widespread land-system changes, including shifts to different regimes in China, Vietnam and Indonesia, whereas land systems in Laos remained stable in the study...

  18. Globalisation, the "Idea of a University" and Its Ethical Regimes

    Science.gov (United States)

    Marginson, Simon

    2007-01-01

    This paper sketches the impact of globalisation and internationalisation on the terrain of values and ethics in higher education. The first part of the paper discusses values and ethics in higher education in relation to the "Idea of a University", and identifies the ethical regimes essential to the functioning of HEIs as knowledge-forming…

  19. Morphodynamic regime and long-term evolution of meandering rivers

    Science.gov (United States)

    Frascati, Alessandro; Lanzoni, Stefano

    2009-06-01

    In the present contribution we focus our attention on the long-term behavior of meandering rivers, a very common pattern in nature. This class of dynamical systems is driven by the coexistence of various intrinsically nonlinear mechanisms which determine the possible occurrence of two different morphodynamic regimes: the subresonant and the superresonant regimes. Investigating the full range of morphodynamic conditions, we objectively compare the morphologic characteristics exhibited by synthetically generated and observed planimetric patterns. The analysis is carried out examining, through principal component analysis, a suitable set of morphological variables. We show that even in the presence of the strong filtering action exerted by cutoff processes, a closer, although not yet complete, similarity with natural meandering planforms can be achieved only by adopting a flow field model which accounts for the full range of morphodynamic regimes. We also introduce a new morphodynamic length scale, ?m, associated with spatially oscillating disturbances. Once normalized with this length scale, the relevant morphologic features of the simulated long-term patterns (e.g., the probability density function of local curvature and the geometric characteristics of oxbow lakes) tend to collapse on two distinct behaviors, depending on the dominant morphologic regime.

  20. Analysis of the Two-Regime Method on Square Meshes

    KAUST Repository

    Flegg, Mark B.

    2014-01-01

    The two-regime method (TRM) has been recently developed for optimizing stochastic reaction-diffusion simulations [M. Flegg, J. Chapman, and R. Erban, J. Roy. Soc. Interface, 9 (2012), pp. 859-868]. It is a multiscale (hybrid) algorithm which uses stochastic reaction-diffusion models with different levels of detail in different parts of the computational domain. The coupling condition on the interface between different modeling regimes of the TRM was previously derived for onedimensional models. In this paper, the TRM is generalized to higher dimensional reaction-diffusion systems. Coupling Brownian dynamics models with compartment-based models on regular (square) two-dimensional lattices is studied in detail. In this case, the interface between different modeling regimes contains either flat parts or right-angle corners. Both cases are studied in the paper. For flat interfaces, it is shown that the one-dimensional theory can be used along the line perpendicular to the TRM interface. In the direction tangential to the interface, two choices of the TRM parameters are presented. Their applicability depends on the compartment size and the time step used in the molecular-based regime. The two-dimensional generalization of the TRM is also discussed in the case of corners. © 2014 Society for Industrial and Applied Mathematics.

  1. The perturbative Regge-calculus regime of loop quantum gravity

    Energy Technology Data Exchange (ETDEWEB)

    Bianchi, Eugenio [Scuola Normale Superiore and INFN Pisa, Piazza dei Cavalieri 7, I-56126 Pisa (Italy)], E-mail: e.bianchi@sns.it; Modesto, Leonardo [Department of Physics, Bologna University and INFN Bologna, V. Irnerio 46, I-40126 Bologna (Italy); Centre de Physique Theorique de Luminy, Universite de la Mediterranee, F-13288 Marseille (France)], E-mail: modesto@bo.infn.it

    2008-06-21

    The relation between loop quantum gravity and Regge calculus has been pointed out many times in the literature. In particular the large spin asymptotics of the Barrett-Crane vertex amplitude is known to be related to the Regge action. In this paper we study a semiclassical regime of loop quantum gravity and show that it admits an effective description in terms of perturbative area-Regge-calculus. The regime of interest is identified by a class of states given by superpositions of four-valent spin networks, peaked on large spins. As a probe of the dynamics in this regime, we compute explicitly two- and three-area correlation functions at the vertex amplitude level. We find that they match with the ones computed perturbatively in area-Regge-calculus with a single 4-simplex, once a specific perturbative action and measure have been chosen in the Regge-calculus path integral. Correlations of other geometric operators and the existence of this regime for other models for the dynamics are briefly discussed.

  2. Second regime tokamak operation at large aspect ratio

    International Nuclear Information System (INIS)

    The equilibrium, stability, and transport properties of large aspect ratio tokamaks operating at the second stability regime are described theoretically using numerical and analytical techniques. It has been shown that, at large aspect ratio, significant current profile control is possible with relatively modest amounts of neutral beam current drive, and the power needed to access and maintain the second regime operation is calculated to be about 3 MW using the results of an integrated 1.5D transport and stability code. An example second regime experiment has been described and the results are presented of extensive calculations illustrating several possible operating scenarios, external and internal model stability boundaries, and the experimental features needed to evaluate and test the high beta tokamak theories. The theory which describes the stabilizing effect of energetic particles during high beta operation was extended to finite aspect ratio. A key technical problem for application of this technique appears to be caused by ripple transport. Plasma rotation effects are found to be generally destabilizing and several other schemes for improved access to the second stability regime are discussed including ponderomotive stabilization of the plasma edge region and active feedback control

  3. Learning, competency nomads, and post-signifying regimes

    DEFF Research Database (Denmark)

    Krejsler, John

    2007-01-01

    of these changes as a transition from ‘industrial' to ‘knowledge society'; this is done by re-describing this transition from within as a transition from ‘signifying' to ‘post-signifying' regimes. From this conceptual experiment the ‘competency nomad' emerges as a powerful concept that seems useful to replace...

  4. Perfect photon absorption in nonlinear regime of cavity quantum electrodynamics

    CERN Document Server

    Agarwal, G S; Wang, Liyong; Zhu, Yifu

    2016-01-01

    It has been shown that perfect photon absorption can occur in the linear excitation regime of cavity quantum electrodynamics (CQED), in which photons from two identical light fields coupled into two ends of the cavity are completely absorbed and result in excitation of the polariton state of the CQED system. The output light from the cavity is totally suppressed by the destructive interference and the polariton state can only decay incoherently back to the ground state. Here we analyze the perfect photon absorption and onset of optical bistability in the nonlinear regime of the CQED and show that the perfect photon absorption persists in the nonlinear regime of the CQED below the threshold of the optical bistability. Therefore the perfect photon absorption is a phenomenon that can be observed in both linear and nonlinear regimes of CQED. Furthermore, our study reveals for the first time that the optical bistability is influenced by the input-light interference and can be manipulated by varying the relative ph...

  5. Primordial black holes in linear and non-linear regimes

    CERN Document Server

    Allahyari, Alireza; Abolhasani, Ali Akbar

    2016-01-01

    Using the concept of apparent horizon for dynamical black holes, we revisit the formation of primordial black holes (PBH) in the early universe for both linear and non-linear regimes. First, we develop the perturbation theory for spherically symmetric spacetimes to study the formation of spherical PBHs in linear regime and we fix two gauges. We also introduce a well defined gauge invariant quantity for the expansion. Using this quantity, we argue that PBHs do not form in the linear regime. Finally, we study the non-linear regime. We adopt the spherical collapse picture by taking a closed FRW model in the radiation dominated era to investigate PBH formation. Taking the initial condition of the spherical collapse from the linear theory of perturbations, we allow for both density and velocity perturbations. Our model gives a constraint on the velocity perturbation. This model also predicts that the apparent horizon of PBHs forms when $\\delta > 3$. Applying the sound horizon constraint, we have shown the threshol...

  6. Regime-switching models to study psychological process

    NARCIS (Netherlands)

    Hamaker, E.L.; Grasman, R.P.P.P.; Kamphuis, J.H.

    2010-01-01

    Many psychological processes are characterized by recurrent shifts between different states. To model these processes at the level of the individual, regime-switching models may prove useful. In this chapter we discuss two of these models: the threshold autoregressive model and the Markov switching

  7. The human dimension of fire regimes on Earth

    Science.gov (United States)

    Bowman, David M.J.S.; Balch, Jennifer; Artaxo, Paulo; Bond, William J.; Cochrane, Mark A.; D'Antonio, Carla M.; DeFries, Ruth; Johnston, Fay H.; Keeley, Jon E.; Krawchuk, Meg A.; Kull, Christian A.; Michelle, Mack; Moritz, Max A.; Pyne, Stephen; Roos, Christopher I.; Scott, Andrew C.; Sodhi, Navjot S.; Swetnam, Thomas W.

    2011-01-01

    Humans and their ancestors are unique in being a fire-making species, but 'natural' (i.e. independent of humans) fires have an ancient, geological history on Earth. Natural fires have influenced biological evolution and global biogeochemical cycles, making fire integral to the functioning of some biomes. Globally, debate rages about the impact on ecosystems of prehistoric human-set fires, with views ranging from catastrophic to negligible. Understanding of the diversity of human fire regimes on Earth in the past, present and future remains rudimentary. It remains uncertain how humans have caused a departure from 'natural' background levels that vary with climate change. Available evidence shows that modern humans can increase or decrease background levels of natural fire activity by clearing forests, promoting grazing, dispersing plants, altering ignition patterns and actively suppressing fires, thereby causing substantial ecosystem changes and loss of biodiversity. Some of these contemporary fire regimes cause substantial economic disruptions owing to the destruction of infrastructure, degradation of ecosystem services, loss of life, and smoke-related health effects. These episodic disasters help frame negative public attitudes towards landscape fires, despite the need for burning to sustain some ecosystems. Greenhouse gas-induced warming and changes in the hydrological cycle may increase the occurrence of large, severe fires, with potentially significant feedbacks to the Earth system. Improved understanding of human fire regimes demands: (1) better data on past and current human influences on fire regimes to enable global comparative analyses, (2) a greater understanding of different cultural traditions of landscape burning and their positive and negative social, economic and ecological effects, and (3) more realistic representations of anthropogenic fire in global vegetation and climate change models. We provide an historical framework to promote understanding

  8. The human dimension of fire regimes on Earth.

    Science.gov (United States)

    Bowman, David M J S; Balch, Jennifer; Artaxo, Paulo; Bond, William J; Cochrane, Mark A; D'Antonio, Carla M; Defries, Ruth; Johnston, Fay H; Keeley, Jon E; Krawchuk, Meg A; Kull, Christian A; Mack, Michelle; Moritz, Max A; Pyne, Stephen; Roos, Christopher I; Scott, Andrew C; Sodhi, Navjot S; Swetnam, Thomas W; Whittaker, Robert

    2011-12-01

    Humans and their ancestors are unique in being a fire-making species, but 'natural' (i.e. independent of humans) fires have an ancient, geological history on Earth. Natural fires have influenced biological evolution and global biogeochemical cycles, making fire integral to the functioning of some biomes. Globally, debate rages about the impact on ecosystems of prehistoric human-set fires, with views ranging from catastrophic to negligible. Understanding of the diversity of human fire regimes on Earth in the past, present and future remains rudimentary. It remains uncertain how humans have caused a departure from 'natural' background levels that vary with climate change. Available evidence shows that modern humans can increase or decrease background levels of natural fire activity by clearing forests, promoting grazing, dispersing plants, altering ignition patterns and actively suppressing fires, thereby causing substantial ecosystem changes and loss of biodiversity. Some of these contemporary fire regimes cause substantial economic disruptions owing to the destruction of infrastructure, degradation of ecosystem services, loss of life, and smoke-related health effects. These episodic disasters help frame negative public attitudes towards landscape fires, despite the need for burning to sustain some ecosystems. Greenhouse gas-induced warming and changes in the hydrological cycle may increase the occurrence of large, severe fires, with potentially significant feedbacks to the Earth system. Improved understanding of human fire regimes demands: (1) better data on past and current human influences on fire regimes to enable global comparative analyses, (2) a greater understanding of different cultural traditions of landscape burning and their positive and negative social, economic and ecological effects, and (3) more realistic representations of anthropogenic fire in global vegetation and climate change models. We provide an historical framework to promote understanding

  9. Climate change and future fire regimes: Examples from California

    Science.gov (United States)

    Keeley, Jon E.; Syphard, Alexandra D.

    2016-01-01

    Climate and weather have long been noted as playing key roles in wildfire activity, and global warming is expected to exacerbate fire impacts on natural and urban ecosystems. Predicting future fire regimes requires an understanding of how temperature and precipitation interact to control fire activity. Inevitably this requires historical analyses that relate annual burning to climate variation. Fuel structure plays a critical role in determining which climatic parameters are most influential on fire activity, and here, by focusing on the diversity of ecosystems in California, we illustrate some principles that need to be recognized in predicting future fire regimes. Spatial scale of analysis is important in that large heterogeneous landscapes may not fully capture accurate relationships between climate and fires. Within climatically homogeneous subregions, montane forested landscapes show strong relationships between annual fluctuations in temperature and precipitation with area burned; however, this is strongly seasonal dependent; e.g., winter temperatures have very little or no effect but spring and summer temperatures are critical. Climate models that predict future seasonal temperature changes are needed to improve fire regime projections. Climate does not appear to be a major determinant of fire activity on all landscapes. Lower elevations and lower latitudes show little or no increase in fire activity with hotter and drier conditions. On these landscapes climate is not usually limiting to fires but these vegetation types are ignition-limited. Moreover, because they are closely juxtaposed with human habitations, fire regimes are more strongly controlled by other direct anthropogenic impacts. Predicting future fire regimes is not rocket science; it is far more complicated than that. Climate change is not relevant to some landscapes, but where climate is relevant, the relationship will change due to direct climate effects on vegetation trajectories, as well as

  10. Early warning of atmospheric regime transitions using transfer operators

    Science.gov (United States)

    Tantet, Alexis; Dijkstra, Henk

    2015-04-01

    The existence of persistent midlatitude atmospheric regimes, such as blocking events, with time scales larger than 5-10 days and indications of preferred transition paths between them motivates the development of early-warning indicators of regime transitions. Here, we use a barotropic model of the northern midlatitudes winter flow to study such meta-stable regimes. We look at estimates of transfer operators acting on densities evolving on a reduced phase space spanned by the first Empirical Orthogonal Functions of the streamfunction and develop an early-warning indicator of zonal to blocked flow transition. The study of the spectra of transfer operators estimated for different lags reveals a multi-level structure in the flow as well as the effect of memory on the reduced dynamics due to past interactions between the resolved and unresolved variables. The slowest motions in the reduced phase space are thereby found to have time scales larger than 8 days and to behave as Markovian for larger lags. These motions are associated with meta-stable regimes and their transitions and can be detected as almost-invariant sets of the transfer operator. The early-warning indicator is based on the action on an initial density of products of the transfer operators estimated for sufficiently long lags, making use of the semi-group property of these operators and shows relatively good Peirce skill score. From the energy budget of the model, we are able to explain the meta-stability of the regimes and the existence of preferred transition paths as the manifestation of barotropic instability. Finally, even though the model is highly simplified, the skill of the early warning indicator is promising, suggesting that the transfer operator approach can be used in parallel to an operational deterministic model for stochastic prediction or to assess forecast uncertainty.

  11. How will climate change modify river flow regimes in Europe?

    Directory of Open Access Journals (Sweden)

    C. Schneider

    2012-08-01

    Full Text Available Worldwide, flow regimes are being modified by various anthropogenic impacts and climate change induces an additional risk. Rising evapotranspiration rates, declining snow cover and changing precipitation patterns will interact differently at different locations. Consequently, in distinct climate zones, unequal consequences can be expected in matters of water stress, flood risk, water quality, and food security. In particular, river ecosystems and their vital ecosystem services will be compromised as their species richness and composition have evolved over long time under natural flow conditions. This study aims at evaluating the exclusive impacts of climate change on river flow regimes in Europe. Various flow characteristics are taken into consideration and diverse dynamics are identified for each distinct climate zone in Europe. In order to simulate natural and modified flow regimes, the global hydrology model WaterGAP3 is applied. All calculations for current and future conditions (2050s are carried out on a 5' × 5' European grid. To address uncertainty, climate forcing data of three different global climate models are used to drive WaterGAP3. Finally, the hydrological alterations of different flow characteristics are quantified by the Indicators of Hydrological Alteration approach. Results of our analysis indicate that on European scale, climate change can be expected to modify flow regimes significantly. This is especially the case in the Mediterranean climate zone (due to drier conditions with reduced precipitation across the year and in the continental climate zone (due to reduced snowmelt and drier summers. Regarding single flow characteristics, strongest impacts on timing were found for the boreal climate zone. This applies for both, high and low flows. While low flow magnitudes are likely to be stronger influenced in the Mediterranean climate, high flow magnitudes will be mainly altered in snow climates with warmer summers. At the end

  12. Climate Change and Future Fire Regimes: Examples from California

    Directory of Open Access Journals (Sweden)

    Jon E. Keeley

    2016-08-01

    Full Text Available Climate and weather have long been noted as playing key roles in wildfire activity, and global warming is expected to exacerbate fire impacts on natural and urban ecosystems. Predicting future fire regimes requires an understanding of how temperature and precipitation interact to control fire activity. Inevitably this requires historical analyses that relate annual burning to climate variation. Fuel structure plays a critical role in determining which climatic parameters are most influential on fire activity, and here, by focusing on the diversity of ecosystems in California, we illustrate some principles that need to be recognized in predicting future fire regimes. Spatial scale of analysis is important in that large heterogeneous landscapes may not fully capture accurate relationships between climate and fires. Within climatically homogeneous subregions, montane forested landscapes show strong relationships between annual fluctuations in temperature and precipitation with area burned; however, this is strongly seasonal dependent; e.g., winter temperatures have very little or no effect but spring and summer temperatures are critical. Climate models that predict future seasonal temperature changes are needed to improve fire regime projections. Climate does not appear to be a major determinant of fire activity on all landscapes. Lower elevations and lower latitudes show little or no increase in fire activity with hotter and drier conditions. On these landscapes climate is not usually limiting to fires but these vegetation types are ignition-limited. Moreover, because they are closely juxtaposed with human habitations, fire regimes are more strongly controlled by other direct anthropogenic impacts. Predicting future fire regimes is not rocket science; it is far more complicated than that. Climate change is not relevant to some landscapes, but where climate is relevant, the relationship will change due to direct climate effects on vegetation

  13. Detecting regime shifts in the ocean: Data considerations [review article

    Science.gov (United States)

    deYoung, B.; Harris, R.; Alheit, J.; Beaugrand, G.; Mantua, N.; Shannon, L.

    2004-02-01

    We review observational data sets that have been used to detect regime shifts in the ocean. Through exploration of data time series we develop a definition of a regime shift from a pragmatic perspective, in which a shift is considered as an abrupt change from a quantifiable ecosystem state. We conclude that such changes represent a restructuring of the ecosystem state in some substantial sense that persists for long enough that a new quasi-equilibrium state can be observed. The abruptness of the shift is relative to the life-scale or the reproductive time-scale of the higher predators that are influenced by the shift. In general, the event-forcing is external to the biological ecosystem, usually the physical climate system, but we also identify shifts that can be ascribed to anthropogenic forcing, in our examples fishing. This pragmatic definition allows for several different types of regime shift ranging from simple biogeographic shifts to non-linear state changes. In practice it is quite difficult to determine whether observed changes in an oceanic ecosystem are primarily spatial or temporally regulated. The determination of ecosystem state remains an unresolved, and imprecise, oceanographic problem. We review observations and interpretation from several different oceanic regions as examples to illustrate this pragmatic definition of a regime shift: the Northeast Pacific, the Northwest and Northeast Atlantic, and Eastern Boundary Currents. For each region, different types of data (biological and physical) are available for differing periods of time, and we conclude, with varying degrees of certainty, whether a regime shift is in fact detectable in the data.

  14. Regimes of science production and diffusion: towards a transverse organization of knowledge

    Directory of Open Access Journals (Sweden)

    Anne Marcovich

    2012-01-01

    Full Text Available This article is a contribution to the critical sociology of science perspective introduced and developed by Pierre Bourdieu. The paper proposes a transversalist theory of science and technology production and diffusion. It is here argued that science and technology are comprised of multiple regimes where each regime is historically grounded, possesses its own division of labour, modes of cognitive and artifact production and has specific audiences. The major regimes include the disciplinary regime, utilitarian regime, transitory regime and research-technology regime. Though each regime is autonomous, they are simultaneously closely interlaced. In science and technology, autonomy is not antithetical to interdependence and reciprocity. This study demonstrates for the four specified regimes of production and diffusion that differentiation is not contrary to interaction. In science, differentiation and interaction comprise two sides of the same coin. All regimes exhibit a measure of transversality.

  15. Numerical simulation of flows from free molecular regime to continuum regime by a DVM with streaming and collision processes

    Science.gov (United States)

    Yang, L. M.; Shu, C.; Wu, J.; Wang, Y.

    2016-02-01

    A discrete velocity method (DVM) with streaming and collision processes is presented in this work for simulation of flows from free molecular regime to continuum regime. The present scheme can be considered as a semi-Lagrangian like scheme. At first, we follow the conventional DVM to discretize the phase velocity space by a number of discrete velocities. Then, for each discrete velocity, the kinetic equation with BGK-Shakhov model is integrated in space and time within one time step. As a result, a simple algebraic formulation can be obtained, and its solution can be marched in time by the streaming and collision processes. However, differently from the conventional semi-Lagrangian scheme, the present scheme uses the MUSCL approach with van Albada limiter in the process of reconstructing the distribution function at the surrounding points of the cell center, and the transport distance is controlled in order to avoid extrapolation. This makes the present scheme be capable of simulating the hypersonic rarefied flows. In addition, as compared to the unified gas kinetic scheme (UGKS), the present scheme is simpler and easier for implementation. Thus, the computational efficiency can be improved accordingly. To validate the proposed numerical scheme, test examples from free molecular regime to continuum regime are simulated. Numerical results showed that the present scheme can predict the flow properties accurately even for hypersonic rarefied flows.

  16. Exchange Rate Regimes – A periodical overview and a critical analysis of exchange rate regimes in Kosovo

    Directory of Open Access Journals (Sweden)

    Flamur Bunjaku

    2015-03-01

    Full Text Available Exchange rate regimes and the monetary policy are the key instruments governments use to achieve their economic and financial objectives. Moreover, due to global financial crisis the latter instruments get more importance. Empirical evidences show that exchange rate regimes in Kosovo and its monetary policy throughout their development were mainly influenced by different political and historical developments. In regard of Euroisation of monetary system in Kosovo it was found that this action generated macro - financial stability in terms of inflation and price fluctuation. However, in terms of microeconomic aspects, the unilateral adaptation of Euro as the official currency of Kosovo failed to provide microeconomic advantages such as to export stimulation, and so forth. The main exchange rate regime systems were discussed focusing in their advantages and disadvantages, and it was concluded that there is no commonly accepted theory regarding the optimality of exchange rate regimes. In addition, the global financial crisis impact in the financial system of Kosovo is also discussed and it was found that negative impacts of global financial crisis were moderate and indirect.

  17. Mechanical surface treatment of steel-Optimization parameters of regime

    Science.gov (United States)

    Laouar, L.; Hamadache, H.; Saad, S.; Bouchelaghem, A.; Mekhilef, S.

    2009-11-01

    Mechanical treatment process by superficial plastic deformation is employed for finished mechanical part surface. It introduces structural modifications that offer to basic material new properties witch give a high quality of physical and geometrical on superficial layers. This study focuses on the application of burnishing treatment (ball burnishing) on XC48 steel and parameters optimisation of treatment regime. Three important parameters were considered: burnishing force ' Py', burnishing feed 'f' and ball radius 'r'. An empirical model has been developed to illustrate the relationship between these parameters and superficial layer characteristics defined by surface roughness ' Ra' and superficial hardness ' Hv'. A program was developed in order to determine the optimum treatment regimes for each characteristic.

  18. Nano-optomechanical measurement in the photon counting regime

    CERN Document Server

    de Lépinay, Laure Mercier; Rohr, Sven; Gloppe, Arnaud; Kuhn, Aurélien; Verlot, Pierre; Dupont-Ferrier, Eva; Besga, Benjamin; Arcizet, Olivier

    2015-01-01

    Optically measuring in the photon counting regime is a recurrent challenge in modern physics and a guarantee to develop weakly invasive probes. Here we investigate this idea on a hybrid nano-optomechanical system composed of a nanowire hybridized to a single Nitrogen-Vacancy (NV) defect. The vibrations of the nanoresonator grant a spatial degree of freedom to the quantum emitter and the photon emission event can now vary in space and time. We investigate how the nanomotion is encoded on the detected photon statistics and explore their spatio-temporal correlation properties. This allows a quantitative measurement of the vibrations of the nanomechanical oscillator at unprecedentedly low light intensities in the photon counting regime when less than one photon is detected per oscillation period, where standard detectors are dark-noise-limited. These results have implications for probing weakly interacting nanoresonators, for low temperature experiments and for investigating single moving markers.

  19. Pulsar Timing Arrays and Gravity Tests in the Radiative Regime

    CERN Document Server

    Lee, K J

    2014-01-01

    In this paper, we focus on testing gravity theories in the radiative regime using pulsar timing array observations. After reviewing current techniques to measure the dispersion and alternative polarization of gravitational waves, we extend the framework to the most general situations, where the combinations of a massive graviton and alternative polarization modes are considered. The atlas of the Hellings-Downs functions is completed by the new calculations for these dispersive alternative polarization modes. We find that each mode and corresponding graviton mass introduce characteristic features in the Hellings-Downs function. Thus, in principal, we can not only detect each polarization mode, measure the corresponding graviton mass, but also discriminate the different scenarios. In this way, we can test gravity theories in the radiative regime in a generalized fashion, and such method is a direct experiment, where one can address the gauge symmetry of the gravity theories in their linearised limits. Although ...

  20. New Mobilities Regimes in Art and Social Sciences

    DEFF Research Database (Denmark)

    Witzgall, Susanne; Vogl, Gerlinde; Kesselring, Sven

    New Mobilities Regimes analyses how global mobilities are changing the world of today and the role of political and economic power. Bringing together essays by leading scholars and social scientists, including Mimi Sheller and Bülent Diken with the work of well-known artists and art theorists....... Illustrated by a range of studies which examine the regulation and structure of mobility, such as the daily routines of teleworkers, Ukrainian cleaners in Western Europe, the mobility policies of global corporations, and the impact of bicycle policies on public space, New Mobilities Regimes emphasizes...... the routes and crossroads of migration flows as well as at the interaction of mobility and new spatial concepts. The contributors are concerned with both the positive outcomes and the disappointments of the global mobilizations in modern lives. This book is ground-breaking in that it calls...

  1. The case for regime-based water quality standards

    Science.gov (United States)

    Poole, Geoffrey C.; Dunham, J.B.; Keenan, D.M.; Sauter, S.T.; McCullough, D.A.; Mebane, Christopher; Lockwood, Jeffrey C.; Essig, Don A.; Hicks, Mark P.; Sturdevant, Debra J.; Materna, E.J.; Spalding, M.; Risley, John; Deppman, Marianne

    2004-01-01

    Conventional water quality standards have been successful in reducing the concentration of toxic substances in US waters. However, conventional standards are based on simple thresholds and are therefore poorly structured to address human-caused imbalances in dynamic, natural water quality parameters, such as nutrients, sediment, and temperature. A more applicable type of water quality standarda??a a??regime standarda??a??would describe desirable distributions of conditions over space and time within a stream network. By mandating the protection and restoration of the aquatic ecosystem dynamics that are required to support beneficial uses in streams, well-designed regime standards would facilitate more effective strategies for management of natural water quality parameters.

  2. Adaptive two-regime method: application to front propagation

    CERN Document Server

    Robinson, Martin; Erban, Radek

    2013-01-01

    The Adaptive Two-Regime Method (ATRM) is developed for hybrid (multiscale) stochastic simulation of reaction-diffusion problems. It efficiently couples detailed Brownian dynamics simulations with coarser lattice-based models. The ATRM is a generalization of the previously developed Two-Regime Method [Flegg et al, Journal of the Royal Society Interface, 2012] to multiscale problems which require a dynamic selection of regions where detailed Brownian dynamics simulation is used. Typical applications include a front propagation or spatio-temporal oscillations. In this paper, the ATRM is used for an in-depth study of front propagation in a stochastic reaction-diffusion system which has its mean-field model given in terms of the Fisher equation [Fisher, Annals of Eugenics, 1937]. It exhibits a travelling reaction front which is sensitive to stochastic fluctuations at the leading edge of the wavefront. Previous studies into stochastic effects on the Fisher wave propagation speed have focused on lattice-based models...

  3. A Cold-Strontium Laser in the Superradiant Crossover Regime

    CERN Document Server

    Norcia, Matthew A

    2015-01-01

    Recent proposals suggest that lasers based on narrow dipole-forbidden transitions in cold alkaline earth atoms could achieve linewidths that are orders of magnitude smaller than linewidths of any existing lasers. Here, we demonstrate a laser based on the 7.5 kHz linewidth dipole forbidden $^3 $P$_1$ to $^1 $S$_0$ transition in laser-cooled and tightly confined $^{88}$Sr. We can operate this laser in the bad-cavity regime, where coherence is primarily stored in the atoms, or continuously tune to the more conventional good-cavity regime, where coherence is primarily stored in the light field. We show that the cold-atom gain medium can be repumped to achieve quasi steady-state lasing, and demonstrate up to an order of magnitude suppression in the sensitivity of laser frequency to changes in cavity length, the primary limitation for the most frequency stable lasers today.

  4. A Cold-Strontium Laser in the Superradiant Crossover Regime

    Science.gov (United States)

    Norcia, Matthew; Thompson, James

    2016-05-01

    We demonstrate and study a laser based on the 7.5 kHz linewidth dipole forbidden 3 P1 to 1 S0 transition in laser-cooled and tightly confined 88 Sr. We can operate this laser in the bad-cavity or superradiant regime, where coherence is primarily stored in the atoms, or continuously tune to the more conventional good-cavity regime, where coherence is primarily stored in the light field. We show that the cold-atom gain medium can be repumped to achieve quasi steady-state lasing. We also demonstrate up to an order of magnitude suppression in the sensitivity of laser frequency to changes in cavity length, verifying a key feature of proposed narrow linewidth lasers based on dipole-forbidden transitions in alkaline earth atoms.

  5. Option Pricing when the Regime-Switching Risk is Priced

    Institute of Scientific and Technical Information of China (English)

    Tak Kuen Siu; Hailiang Yang

    2009-01-01

    We study the pricing of an option when the price dynamic of the underlying risky asset is governed by a Markov-modulated geometric Brownian motion. We suppose that the drift and volatility of the underlying risky asset are modulated by an observable continuous-time, finite-state Markov chain. We develop a twostage pricing model which can price both the diffusion risk and the regime-switching risk based on the Esscher transform and the minimization of the maximum entropy between an equivalent martingale measure and the real-world probability measure over different states. Numerical experiments are conducted and their results reveal that the impact of pricing regime-switching risk on the option prices is significant.

  6. Onset of the Asymptotic Regime for Finite Orders

    CERN Document Server

    Henson, Joe; Sorkin, Rafael D; Surya, Sumati

    2015-01-01

    We describe a Markov-Chain-Monte-Carlo algorithm which can be used to generate naturally labeled n-element posets at random with a probability distribution of one's choice. Implementing this algorithm for the uniform distribution, we explore the approach to the asymptotic regime in which almost every poset takes on the three-layer structure described by Kleitman and Rothschild (KR). By tracking the n-dependence of several order-invariants, among them the height of the poset, we observe an oscillatory behavior which is very unlike a monotonic approach to the KR regime. Only around n=40 or so does this "finite size dance" appear to give way to a gradual crossover to asymptopia which lasts until n=85, the largest n we have simulated.

  7. Biphoton spectroscopy in a strongly nondegenerate regime of SPDC

    International Nuclear Information System (INIS)

    The absorption spectrum of Cr3+ ions in Al2O3 crystal in the range from 691 nm to 697 nm was measured at the room temperature using the biphoton light generated by nondegenerate spontaneous parametric down-conversion of the He-Cd laser radiation (325 nm) in the LiIO3 crystal. The spectrum of the sample was measured by counting the coincidences when signal photons go through the impurity crystal, whilst the wavelength of the idler photons is resolved by a monochromator. A strongly nondegenerate regime of SPDC, when the difference in frequencies of correlated photons exceeds significantly their spectral width, was used in the biphoton spectroscopy for the first time. Such a regime allows one to obtain an absorption spectrum by measuring the wavelength in a completely different spectral range

  8. Biphoton spectroscopy in a strongly nondegenerate regime of SPDC

    Science.gov (United States)

    Kalachev, A. A.; Kalashnikov, D. A.; Kalinkin, A. A.; Mitrofanova, T. G.; Shkalikov, A. V.; Samartsev, V. V.

    2008-08-01

    The absorption spectrum of Cr3+ ions in Al2O3 crystal in the range from 691 nm to 697 nm was measured at the room temperature using the biphoton light generated by nondegenerate spontaneous parametric down-conversion of the He-Cd laser radiation (325 nm) in the LiIO3 crystal. The spectrum of the sample was measured by counting the coincidences when signal photons go through the impurity crystal, whilst the wavelength of the idler photons is resolved by a monochromator. A strongly nondegenerate regime of SPDC, when the difference in frequencies of correlated photons exceeds significantly their spectral width, was used in the biphoton spectroscopy for the first time. Such a regime allows one to obtain an absorption spectrum by measuring the wavelength in a completely different spectral range.

  9. Adult learning, education, and the labour market inthe employability regime

    Directory of Open Access Journals (Sweden)

    Staffan Nilsson

    2013-10-01

    Full Text Available The purpose of this paper is to draw on the research and scholarly literature to explorethe changing discourses and perspectives concerning adult learning, education, and thelabour market in the employability regime. The focus of the nalysis is a Nordic context.The dominant employability regime maintains a technical-rational perspective onlearning and employability. Education is predominantly regarded as an instrumentalpreparation for the labour market. The future demands of the labour market are largelyunknown, however, and vocational and professional training may not provide sufficientpreparation for the increasing complexities of work. Theoretical discussions have beendominated by an alleged mismatch between individual competence and thequalifications that are required in the world of work. There is no consensus regardinghow the gap should be described, explained, or bridged. New demands on educationaldesign have emerged, and ideas related to liberal education and ‘bildung’ have beenreinserted into the political agenda, offering general preparation for a wider array ofchallenges.

  10. Heavy ion acceleration in the Breakout Afterburner regime

    CERN Document Server

    Petrov, G M; Thomas, A G R; Krushelnick, K; Beg, F N

    2015-01-01

    Theoretical study of heavy ion acceleration from an ultrathin (20 nm) gold foil irradiated by sub-picosecond lasers is presented. Using two dimensional particle-in-cell simulations we identified two highly efficient ion acceleration schemes. By varying the laser pulse duration we observed a transition from Radiation Pressure Acceleration to the Breakout Afterburner regime akin to light ions. The underlying physics and ion acceleration regimes are similar to that of light ions, however, nuances of the acceleration process make the acceleration of heavy ions more challenging. Two laser systems are studied in detail: the Texas Petawatt Laser and the Trident laser, the former having pulse duration 180 fs, intermediate between very short femtosecond pulses and picosecond pulses. Both laser systems generated directional gold ions beams (~10 degrees half-angle) with fluxes in excess of 1011 ion/sr and normalized energy >10 MeV/nucleon.

  11. The regime and the constitutional principles from 1938

    Directory of Open Access Journals (Sweden)

    Florin Grecu

    2012-12-01

    Full Text Available The authoritarian monarchy regime, from 1938-1940, functioned based on an exceptional status, because it was founded on a decree-law of state of siege and therefore all the power in the State was held in the hands of the army colonels and generals. By suspending the political parties, the political pluralism and the Parliament, the basic institutions of a democratic regime were abolished. Press censorship, the denying of the right to manifest and gather were assigned to the army and the militarization of the State institutions became a reality. The proclamation of the King as an absolute leader of the unique party and of the government transformed Romania into a ministerial and undemocratic monarchy, with authoritarian valence.

  12. Automatic Classification of Offshore Wind Regimes With Weather Radar Observations

    DEFF Research Database (Denmark)

    Trombe, Pierre-Julien; Pinson, Pierre; Madsen, Henrik

    2014-01-01

    fluctuations. The information they provide could then be integrated into an advanced prediction system for improving offshore wind power predictability and controllability. In this paper, we address the automatic classification of offshore wind regimes (i.e., wind fluctuations with specific frequency...... systems are extracted from weather radar images. These attributes describe the global intensity, spatial continuity and motion of precipitation echoes on the images. Finally, a CART classification tree is used to find the broad relationships between precipitation attributes and wind regimes......Weather radar observations are called to play an important role in offshore wind energy. In particular, they can enable the monitoring of weather conditions in the vicinity of large-scale offshore wind farms and thereby notify the arrival of precipitation systems associated with severe wind...

  13. THE POLICY AND THE TRADE REGIME IN ROMANIA AFTER 1990

    Directory of Open Access Journals (Sweden)

    Dobrotă Gabriela

    2009-11-01

    Full Text Available The growth of connections between national economies has generated a consolidation of foreign currency activities, requiring a continuous adjusting regime, both for the foreign currency policy and for the exchange rate to the market mechanisms. In Romania, there have been frequent alterations of the foreign currency policy, requiring the need to create a juridical framework adequate for the market economy and the evolution of financial instruments. This paper presents the main characteristics of the trade regime and the exchange rate policy in Romania after 1990. Practically, the paper reflects a radiography of the main events on the Romanian foreign exchange rate within the context of specific conditions of the Romanian economy and in correlation with the measures adopted by countries from the Central Europe.

  14. THE POLICY AND THE TRADE REGIME IN ROMANIA AFTER 1990

    Directory of Open Access Journals (Sweden)

    Dobrotă Gabriela

    2009-11-01

    Full Text Available The growth of connections between national economies has generated a consolidation of foreign currency activities, requiring a continuous adjusting regime, both for the foreign currency policy and for the exchange rate to the market mechanisms. In Romania, there have been frequent alterations of the foreign currency policy, requiring the need to create a juridical framework adequate for the market economy and the evolution of financial instruments. This paper presents the main characteristics of the trade regime and the exchange rate policy in Romania after 1990. Practically, the paper reflects a radiography of the main events on the Romanian foreign exchange rate within the context of specific conditions of the Romanian economy and in correlation with the measures adopted by countries from the Central Europe

  15. Relationship between fire regime and vegetation symphenological timing in Sardinia

    Directory of Open Access Journals (Sweden)

    Carlo Ricotta

    2008-01-01

    Full Text Available Fire is a basic ecological factor that contributes to determine vegetation biodiversity and dynamics in time and space. Fuel characteristics play an essential role in fire ignition and propagation; for instance fuel availability and flammability are closely related to the coarse-scale vegetation phenological trends that directly affect wildfire distribution in time and space. In this perspective, the annual NDVI profiles derived from high temporal resolution satellite images like SPOT Vegetation represent an effective tool for monitoring plant seasonal dynamics at the landscape scale. The objective of this study consists in relating the wildfire regime in Sardinia during 2000-2004 with the remotely sensed phenological parameters of the vegetation, segmented according to potential natural vegetation characteristics. The results of our study highlight a good correspondence between the NDVI temporal dynamics of the potential natural vegetation of Sardinia and the corresponding fires regime characteristics.

  16. $H_{2}$ Formation on Interstellar Grains in Different Physical Regimes

    CERN Document Server

    Biham, O; Katz, N; Pirronello, V; Vidali, G

    1998-01-01

    An analysis of the kinetics of H2 formation on interstellar dust grains is presented using rate equations. It is shown that semi-empirical expressions that appeared in the literature represent two different physical regimes. In particular, it is shown that the expression given by Hollenbach, Werner and Salpeter [ApJ, 163, 165 (1971)] applies when high flux, or high mobility, of H atoms on the surface of a grain, makes it very unlikely that H atoms evaporate before they meet each other and recombine. The expression of Pirronello et al.\\ [ApJ, 483, L131 (1997)] -- deduced on the basis of accurate measurements on realistic dust analogue -- applies to the opposite regime (low coverage and low mobility). The implications of this analysis for the understanding of the processes dominating in the Interstellar Medium are discussed.

  17. Accretion to a Magnetized Neutron Star in the "Propeller" Regime

    CERN Document Server

    Toropina, O D; Lovelace, R V E

    2006-01-01

    We investigate spherical accretion to a rotating magnetized star in the "propeller" regime using axisymmetric resistive magnetohydrodynamic simulations. The regime is predicted to occur if the magnetospheric radius is larger than the corotation radius and smaller than the light cylinder radius. The simulations show that accreting matter is expelled from the equatorial region of the magnetosphere and that it moves away from the star in a supersonic, disk-shaped outflow. At larger radial distances the outflow slows down and becomes subsonic. The equatorial matter outflow is initially driven by the centrifugal force, but at larger distances the pressure gradient force becomes significant. We find the fraction of the Bondi accretion rate which accretes to the surface of the star.

  18. Multifractal regime transition in a modified minority game model

    International Nuclear Information System (INIS)

    The search for more realistic modeling of financial time series reveals several stylized facts of real markets. In this work we focus on the multifractal properties found in price and index signals. Although the usual minority game (MG) models do not exhibit multifractality, we study here one of its variants that does. We show that the nonsynchronous MG models in the nonergodic phase is multifractal and in this sense, together with other stylized facts, constitute a better modeling tool. Using the structure function (SF) approach we detected the stationary and the scaling range of the time series generated by the MG model and, from the linear (non-linear) behavior of the SF we identified the fractal (multifractal) regimes. Finally, using the wavelet transform modulus maxima (WTMM) technique we obtained its multifractal spectrum width for different dynamical regimes.

  19. Political regime and human capital: A cross-country analysis

    OpenAIRE

    Klomp, J.G.; Haan

    2013-01-01

    We examine the relationship between different dimensions of the political regime in place and human capital using a two-step structural equation model. In the first step, we employ factor analysis on 16 human capital indicators to construct two new human capital measures (basic and advanced human capital). In the second step, we estimate the impact of our political variables on human capital, using a cross-sectional structural model for some 100 countries. We conclude that democracy is positi...

  20. CHALLENGES FOR ADOPTING INFLATION TARGETING REGIME IN EGYPT

    OpenAIRE

    Awad, Ibrahim

    2013-01-01

    This study intends to investigate challenges facing the CBE for adopting IT regime. Through exploiting the experience of Czech Republic, Poland, and Brazil in the early days of their adopting IT the study underscores the following challenges; (i) A more active role to be played by the CBE is needed to convince decision-making circuits inside the government for the adoption of IT. (ii) The CBE should be factually independent. (iii) Coordination between monetary policy and fiscal policy should ...

  1. An optimal learning method for developing personalized treatment regimes

    OpenAIRE

    Wang, Yingfei; Powell, Warren

    2016-01-01

    A treatment regime is a function that maps individual patient information to a recommended treatment, hence explicitly incorporating the heterogeneity in need for treatment across individuals. Patient responses are dichotomous and can be predicted through an unknown relationship that depends on the patient information and the selected treatment. The goal is to find the treatments that lead to the best patient responses on average. Each experiment is expensive, forcing us to learn the most fro...

  2. The advantage of international fiscal cooperation under alternative monetary regimes

    DEFF Research Database (Denmark)

    Jensen, Henrik

    1996-01-01

    We consider the strategic interplay between international monetary and fiscal cooperation in a world of interdependent economies. Motivated by the ongoing discussion of monetary unification of Europe, focus is on monetary cooperation, and in particular how its performance is altered by the...... introduction of fiscal (tax) cooperation. Our main result is that fiscal cooperation may be disadvantageous when monetary cooperation lacks credibility with private sectors. On the other hand, fiscal cooperation under a rule based monetary regime is always advantageous...

  3. FISCAL REGIMES IN AND OUTSIDE THE MENA REGION

    OpenAIRE

    IBRAHIM AHMED ELBADAWI; RAIMUNDO SOTO

    2013-01-01

    The 1990s ushered the world not only into a democracy wave, following the collapse of the former Soviet Union, but also into a wave of Fiscal Rules, where the number of countries adopting this fiscal regime steadily rose from only 10 in 1990 to 97 in 2009. Countries that depend on hydrocarbons, in general, tend to suffer from fiscal policies that are highly susceptible to energy price shocks. This provides incentives for implementing fiscal stabilization instruments in the form of fiscal rule...

  4. PHENOMENON OF RESCUING VICTIMS OF NAZI REGIME UNDER THE HOLOCAUST

    OpenAIRE

    Stets, Oleg; Kovtun, Alexander

    2015-01-01

    In this article problems devoted to participation of the local Ukrainian population at the rescue of Jewry victims of the Nazi occupation regime is examined. Question of violation of human rights is analyzed and it is given description a concept «the phenomenon of rescuing». It was concluded on social and legal support rescuers Jewish people during the Second World War on the territory of modern Ukraine.

  5. Capacity of Fading Channels in the Low Power Regime

    KAUST Repository

    Benkhelifa, Fatma

    2013-01-01

    The low power regime has attracted various researchers in the information theory and communication communities to understand the performance limits of wireless systems. Indeed, the energy consumption is becoming one of the major limiting factors in wireless systems. As such, energy-efficient wireless systems are of major importance to the next generation wireless systems designers. The capacity is a metric that measures the performance limit of a wireless system. The study of the ergodic capacity of some fading channels in the low power regime is the main subject of this thesis. In our study, we consider that the receiver has always a full knowledge of the channel state information. However, we assume that the transmitter has possibly imperfect knowledge of the channel state information, i.e. he knows either perfectly the channel or only an estimated version of the channel. Both radio frequency and free space optical communication channel models are considered. The main contribution of this work is the explicit characterization of how the capacity scales as function of the signal-to-noise ratio in the low power regime. This allows us to characterize the gain due to the perfect knowledge compared to no knowledge of the channel state information at the transmitter. In particular, we show that the gain increases logarithmically for radio frequency communication. However, the gain increases as log2(Pavg) or log4(Pavg) for free-space optical communication, where Pavg is the average power constraint imposed to the input. Furthermore, we characterize the capacity of cascaded fading channels and we applied the result to Rayleigh-product fading channel and to a free-space optical link over gamma-gamma atmospheric turbulence in the presence of pointing errors. Finally, we study the capacity of Nakagami-m fading channel under quality of service constraints, namely the effective capacity. We have shown that the effective capacity converges to Shannon capacity in the very low

  6. Electricity Price Modelling with a Regime Switching Volatility

    OpenAIRE

    Silvana Musti; Viviana Fanelli

    2010-01-01

    We present a methodology to model electricity price dynamics by applying the interest rate theory toolkit. We construct the electricity market following [16] and applying the Heath, Jarrow and Morton ([7]) model. The electricity returns forward curve evolution using the Regime Switching Volatility is the instrument chosen to reflect into a simulating model the natural seasonality of electricity prices. The model calibration and the volatility parameters estimation allow to simulate in a reali...

  7. World-Ecology and Ireland: The Neoliberal Ecological Regime

    OpenAIRE

    Sharae Deckard

    2016-01-01

    Since the collapse of the Celtic Tiger, the socio-economic particularity of neoliberal capitalism in its Irish manifestation has increasingly been critiqued, but little attention has been paid to neoliberalism as ecology within Ireland. This article conducts an exploratory survey of the characteristics of the Irish neoliberal ecological regime during and after the Celtic Tiger, identifying the opening of new commodity frontiers (such as fracking, water, agro-biotechnology, and biopharma) cons...

  8. Amendment of the Foreign lnvestment Juridical regime in Colombia

    Directory of Open Access Journals (Sweden)

    Cristina Vargas Guzman

    1992-12-01

    Full Text Available Colombia, integrated in the Andean Group, is now going through a period of economic and institutional modernization and has initiated a serie of modifications, specially of its international trade, finantial, tax, exchange and labour regimes. These have involved some changes which guarantee legislative stability to investors and thus set the grounds for the foreign participation in the economic modernization and internationalization process in Colombia. These facilities need the support of developed countries to achieve its aims.

  9. Decision Making under Ecological Regime Shift: An Experimental Economic Approach

    OpenAIRE

    Kawata, Yukichika

    2011-01-01

    Environmental economics postulates the assumption of homo economicus and presumes that externality occurs as a result of the rational economic activities of economic agents. This paper examines this assumption using an experimental economic approach in the context of regime shift, which has been receiving increasing attention. We observe that when externality does not exist, economic agents (subjects of experimemt) act economically rationally, but when externality exists, economic agents avoi...

  10. Steady state plasma operation in RF dominated regimes on EAST

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, X. J.; Zhao, Y. P.; Gong, X. Z.; Hu, C. D.; Liu, F. K.; Hu, L. Q.; Wan, B. N., E-mail: bnwan@ipp.ac.cn; Li, J. G. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China)

    2015-12-10

    Significant progress has recently been made on EAST in the 2014 campaign, including the enhanced CW H&CD system over 20MW heating power (LHCD, ICRH and NBI), more than 70 diagnostics, ITER-like W-monoblock on upper divertor, two inner cryo-pumps and RMP coils, enabling EAST to investigate long pulse H mode operation with dominant electron heating and low torque to address the critical issues for ITER. H-mode plasmas were achieved by new H&CD system or 4.6GHz LHCD alone for the first time. Long pulse high performance H mode has been obtained by LHCD alone up to 28s at H{sub 98}∼1.2 or by combing of ICRH and LHCD, no or small ELM was found in RF plasmas, which is essential for steady state operation in the future Tokamak. Plasma operation in low collision regimes were implemented by new 4.6GHz LHCD with core Te∼4.5keV. The non-inductive scenarios with high performance at high bootstrap current fraction have been demonstrated in RF dominated regimes for long pulse operation. Near full non-inductive CD discharges have been achieved. In addition, effective heating and decoupling method under multi-transmitter for ICRF system were developed in this campaign, etc. EAST could be in operation with over 30MW CW heating and current drive power (LHCD ICRH NBI and ECRH), enhanced diagnostic capabilities and full actively-cooled metal wall from 2015. It will therefore allow to access new confinement regimes and to extend these regimes towards to steady state operation.

  11. Potential Effects of Climate Change on Mixed Severity Fire Regimes

    OpenAIRE

    Halofsky, Jessica; Peterson, Dave L.

    2009-01-01

    The frequency, severity, and extent of wildfire are strongly related to climate, and increasing temperatures with climate change will likely lead to changes in fire regimes in many types of ecosystems. Increased spring and summer temperatures with climate change will result in relatively early snowmelt, lower summer soil and fuel moisture, and longer fire seasons in the West. These conditions will lead to increased fire frequency and extent. Higher temperatures may also interact with vegetati...

  12. International arbitration and its exclusion from the Brussels regime

    Directory of Open Access Journals (Sweden)

    Hamed Alavi

    2016-06-01

    Full Text Available The Brussels regime, which regulates the matters of transnational litigation excludes arbitration from its scope. Upon formation of the Brussels regime the existing instruments concerning arbitration - the United Nations Convention on Recognition and Enforcement of Foreign Arbitral Awards and the 1961 European Convention on International Commercial Arbitration - were believed to be sufficient. The original Brussels Convention 1968 on recognition and enforcement of judgments delivered in the courts of the EU Member States expressly provided for the exclusion of arbitration. The following Brussels I Regulation followed the trend and reinforced the exclusion of arbitration from their material scopes. The rationale for doing so was primarily the prevention of parallel proceedings and irreconcilable judgments. The arbitration exclusion from the Brussels regime has caused a fair amount of confusion, especially regarding the extent and limits of the exclusion. That is, whether the arbitration agreement, the arbitral award and its consequences are covered by the exclusion or they may fall under the scope of the Brussels regulation if they constitute only an incidental question to the main cause of action? The confusion was illustrated in the ECJ judgment West Tankers, which generated negative feedback from the arbitration community and indicated the need for reform. The recently adopted Recast Regulation took it upon itself to clarify the relationship between arbitration and the EU regime of transnational litigation. The exclusion is reinforced ye again and its boundaries are specified in the Preamble. However, whether or not the concerns about the extent and objectives of arbitration exclusion have been at present eliminated, remains to be seen.

  13. Power Counting Regime of Chiral Extrapolation and Beyond

    CERN Document Server

    Leinweber, D B; Young, R D; Leinweber, Derek B; Thomas, Anthony W; Young, Ross D

    2005-01-01

    Finite-range regularised (FRR) chiral effective field theory is presented in the context of approximation schemes ubiquitous in modern lattice QCD calculations. Using FRR techniques, the power-counting regime (PCR) of chiral perturbation theory can be estimated. To fourth-order in the expansion at the 1% tolerance level, we find m_\\pi < 180 MeV for the PCR, extending only a small distance beyond the physical pion mass.

  14. THERMAL RADIATION LOAD ON TEMPERATURE REGIMES IN PLANT GROWTH CHAMBERS

    OpenAIRE

    Hamasaki, T; Okada, Masumi

    2000-01-01

    In enclosed environments such as a plant growth chamber, thermal radiation plays an important role in determining heat balance and therefore the resultant temperature regimes. In artificially illuminated chambers, a significant level of thermal radiation is emitted from the lamps and/or the lamp house surface. Though there are both shortwave and longwave components in thermal radiation, our measurements in two different chamber designs, with and without thermal radiation filters, showed the l...

  15. Corporate hedging under a resource rent tax regime

    OpenAIRE

    Frestad, Dennis

    2010-01-01

    In addition to the ordinary corporate income tax, special purpose taxes are sometimes levied to extract abnormal profits arising from the use of natural resources. Such dual tax regimes exist in Norway for oil and hydropower, where the corresponding special purpose tax bases are unaffected by any derivatives payments. Dual tax firms with hedging programs therefore face the risk of potentially large discrepancies between the tax bases for corporate income tax and special purpose tax. I investi...

  16. Performance of different tomato cultivars under organic and inorganic regimes

    International Nuclear Information System (INIS)

    To study the performance of different tomato cultivars under organic and inorganic regimes an experiment was conducted at New Developmental Farm, The University of Agriculture, Peshawar, Pakistan during the summer 2013-14. The experiment was laid out in RCBD with split plot arrangement having four replications. Organic regimes (FYM, poultry manure and mushroom compost) and inorganic (NPK) regimes were allotted to main plot, while cultivars (Roma VF, Roma, Super Classic, Bambino and Rio Grande) were subjected to sub plots. Organic and Inorganic regimes significantly (P ≤ 0.01) influenced all the studied attributes of tomato cultivars. Among different cultivars, Roma gave maximum plant survival (93.8 percentage), number of leaves plant (84.1), number of flower inflorescence (5.4), number of fruits inflorescence (4.3), number of fruit plant (25.4), fruit size (63.9 cm) fruit weight plant (9.1 kg) and total yield (22.9 t ha). However, it was closely followed by cultivar Rio Grande for number of leaves plant (79.6), number of flower inflorescence (5.1), number of fruits inflorescence (4.0) and number of fruits plant (24.9). Cultivar Super Classic produced minimum number of leaves plant (67.7), flower inflorescence (4.8), fruit size (60.6 cm), fruit weight plant (8.6 kg) and total yield (21.7 t ha). Similarly, highest plant survival (90.0 percentage), number of flower inflorescence (5.1), number of fruits inflorescence (4.0), number of fruit plant (25.4), fruit size (62.4 ml), fruit weight plant (8.90 kg) and total yield (22.9 t ha) were recorded in plants provided with organic conditions Roma cultivar performed better than other cultivars under the agro climatic condition of Peshawar followed by cultivar Rio Grande. Therefore, organic tomato production, and these two cultivars are recommended to be grown in Peshawar area. (author)

  17. Modeling whistler wave generation regimes in magnetospheric cyclotron maser

    OpenAIRE

    D. L. Pasmanik; A. G. Demekhov; V. Y. Trakhtengerts; M. Parrot

    2004-01-01

    Numerical analysis of the model for cyclotron instability in the Earth's magnetosphere is performed. This model, based on the self-consistent set of equations of quasi-linear plasma theory, describes different regimes of wave generation and related energetic particle precipitation. As the source of free energy the injection of energetic electrons with transverse anisotropic distribution function to the interaction region is considered. A parametric study of the model is performed. The ma...

  18. Idealized Simulations of Precipitation Regimes over Small Tropical Islands

    Science.gov (United States)

    Wang, S.; Sobel, A. H.

    2014-12-01

    Tropical islands are global focal points of convection. Observational studies have shown that precipitation over tropical islands is strongly regulated by their size and elevation, and by the large scale prevailing wind. To further develop physical understanding of convection over tropical islands, we perform a set of highly idealized simulations with uniform sea surface temperature to explore flow regimes around an idealized small island (~120 km wide) as a function of large scale wind speed and island elevation. In our simulations the domain as a whole is in radiative-convective equilibrium (RCE), which constrains the domain average precipitation. The island occupies a small part of the domain, so that significant precipitation variations over the island can occur, compensated by smaller anomalies over the larger surrounding area. Over flat islands, as we vary prevailing wind speed, the island experiences three distinct flow regimes: rainfall is greatly enhanced and a local symmetric circulation is formed in the time mean around the island when the prevailing large scale wind speed is small (0 m/s); but there is little rainfall enhancement when the wind speed is increased to a moderate value (~5 m/s). We interpret these two regimes as the shift of triggering mechanism of convection: thermally forced convection due to surface solar heating dominates when large scale wind is very weak, while mechanically forced convection is favored when the impinging wind is moderate. Further increase of the prevailing wind speed to large values leads to strong asymmetry in the windward and leeward side of island and its coastal area, likely due to gravity waves from flow passing over elevated diurnal heating. Topography has a quantitative impact, but does not alter the qualitative shift of flow regimes as a function of wind speed.

  19. Improving entanglement of two atoms in strong coupling regime

    Science.gov (United States)

    Liu, Hui; Yang, Qing; Yang, Ming; Cao, Zhuoliang

    2016-03-01

    We consider a model of two identical atoms coupled to a single-mode cavity. When in atom-field strong coupling regime, the entanglement of the two atoms with spontaneous emission should be investigated beyond rotating-wave approximation (RWA). In order to improve the entanglement of the two atoms, some typical feedback based on quantum-jump are attempted to impose on the atoms. The result of numerical simulations shows that an appropriate feedback control can improve the entanglement.

  20. Nano-plasmonic antennas in the near infrared regime.

    Science.gov (United States)

    Berkovitch, N; Ginzburg, P; Orenstein, M

    2012-02-22

    Plasmonic nano-antennas constitute a central research topic in current science and engineering with an enormous variety of potential applications. Here we review the recent progress in the niche of plasmonic nano-antennas operating in the near infrared part of the spectrum which is important for a variety of applications. Tuning of the resonance into the near infrared regime is emphasized in the perspectives of fabrication, measurement, modeling, and analytical treatments, concentrating on the vast recent achievements in these areas.

  1. Regime-switching models to study psychological process

    OpenAIRE

    Hamaker, E.L.; Grasman, R.P.P.P.; Kamphuis, J.H.

    2010-01-01

    Many psychological processes are characterized by recurrent shifts between different states. To model these processes at the level of the individual, regime-switching models may prove useful. In this chapter we discuss two of these models: the threshold autoregressive model and the Markov switching autoregressive model. We discuss their main features, and propose estimation methods that can handle missing data. We apply these models to daily affect measurements of an individual diagnosed with...

  2. Practical stability and instability of regime-switching diffusions

    Institute of Scientific and Technical Information of China (English)

    G.George YIN; Bo ZHANG; Chao ZHU

    2008-01-01

    This work is devoted to practical stability of a class of regime-switching diffusions.First,the notion of practical stability is introduced.Then,sufficient conditions for practical stability and practical instability in probability and in pth mean are provided using a Lyapunov function argument.In addition,easily verifiable conditions on drift and diffusion coefficients are also given.Moreover,examples are supplied for demonstration purposes.

  3. MCNP/X TRANSPORT IN THE TABULAR REGIME

    Energy Technology Data Exchange (ETDEWEB)

    HUGHES, H. GRADY [Los Alamos National Laboratory

    2007-01-08

    The authors review the transport capabilities of the MCNP and MCNPX Monte Carlo codes in the energy regimes in which tabular transport data are available. Giving special attention to neutron tables, they emphasize the measures taken to improve the treatment of a variety of difficult aspects of the transport problem, including unresolved resonances, thermal issues, and the availability of suitable cross sections sets. They also briefly touch on the current situation in regard to photon, electron, and proton transport tables.

  4. Analytic expression for poloidal flow velocity in the banana regime

    Energy Technology Data Exchange (ETDEWEB)

    Taguchi, M. [College of Industrial Technology, Nihon University, Narashino 275-8576 (Japan)

    2013-01-15

    The poloidal flow velocity in the banana regime is calculated by improving the l = 1 approximation for the Fokker-Planck collision operator [M. Taguchi, Plasma Phys. Controlled Fusion 30, 1897 (1988)]. The obtained analytic expression for this flow, which can be used for general axisymmetric toroidal plasmas, agrees quite well with the recently calculated numerical results by Parker and Catto [Plasma Phys. Controlled Fusion 54, 085011 (2012)] in the full range of aspect ratio.

  5. The Proactive International Dimension and the Breakdown of Authoritarian Regimes

    OpenAIRE

    Castaldo, Antonino

    2016-01-01

    There is international consensus among scholars that democratic transitions are multicausal processes in which both internal and international variables are involved (Pridham 1991, 1995; Whitehead 1996; Schmitter 1996; Linz and Stepan 1996; Carothers 1999; Morlino and Magen 2008; Grilli di Cortona 2009). This chapter is limited, on the one hand, to the dependent variable consisting solely of the crisis/breakdown/transformation of non-democratic regimes in the Third Wave o...

  6. A Markov Switching Regime Model of Malaysia Property Cycle

    OpenAIRE

    Abdul M. Beksin; Bawa C Abdullahi

    2011-01-01

    Problem statement: Non-linear models such as the Markov Switching regime (MS) method of modelling business cycles, in principle can be used to model property cyle. Approach: The MS model can distinguish property cycle in recession and expansion phases and is sufficiently flexible to allow different relationships to apply over these phases. In this study, the Malaysian property cycle is modelled using a MS model. Results: This technique can be used to simultaneously estimate the data generatin...

  7. The relevance of universal jurisdiction in the complementarity regime

    OpenAIRE

    2012-01-01

    This study examines the relevance universal jurisdiction can have in the ICC complementarity regime. It argues that universal jurisdiction is an underdeveloped principle for exercising jurisdiction, and that the shortcomings of the principle therefore provide it to be exercised with restraint. However, this study also argues that there is a place for universal jurisdiction in those situations where the jurisdiction of the ICC leaves an impunity gap.

  8. The East Asian welfare regime: reality or fiction

    OpenAIRE

    Sarah Kuypers

    2014-01-01

    Recently the debate on the existence of a homogeneous East Asian welfare regime gained prominence because the region is experiencing changes in the fundamentals of its welfare system. Although the majority of the literature builds upon the assumption that there is indeed a fourth welfare type in the region, few empirically investigate whether these countries could formally be regarded as actual ‘Confucian’, ‘productivist’ or ‘developmental’ welfare states. In a detailed, but yet encompassing,...

  9. Newly discovered landscape traps produce regime shifts in wet forests

    OpenAIRE

    Lindenmayer, David B; Hobbs, Richard J; Gene E Likens; Krebs, Charles J.; Banks, Samuel C.

    2011-01-01

    We describe the “landscape trap” concept, whereby entire landscapes are shifted into, and then maintained (trapped) in, a highly compromised structural and functional state as the result of multiple temporal and spatial feedbacks between human and natural disturbance regimes. The landscape trap concept builds on ideas like stable alternative states and other relevant concepts, but it substantively expands the conceptual thinking in a number of unique ways. In this paper, we (i) review the lit...

  10. Regime-based forecast performance during WFIP 1

    Science.gov (United States)

    Freedman, J. M.; Zack, J. W.; Manobianco, J.; Beaucage, P.; Rojowsky, K.

    2015-12-01

    The principal objectives of the first Wind Forecast Improvement Project (WFIP 1) were to improve short-term (0 - 6 hr) wind power forecasts through the assimilation of targeted remote sensing and surface observations with an enhanced model ensemble forcast system. The WFIP 1 field deployment/modeling campaign in the Southern Study Area (SSA--encompassing most of central and western Texas) ran from August 2011 through Septembe 2012. This ensured observational data and model output for all representative weather regimes affecting the SSA. Cold and warm season regimes featured synoptic-scale, convective, and low-level jet (LLJ) phenomena that are responsible for the favorable wind resource in the SSA, and also posed a challenge for assigning specific explanations for the observed forecast improvements (e.g. additional observations, model improvements, or a combination of both). LLJs produced hourly capacity factors exceeding 80% in aggregated wind farm power production, while synoptic-scale systems were responsible for the largest ramp events observed during WFIP 1. Accurately forecasting convective phenomena (such as outflow boundaries) during WFIP 1 was at times problematic. Here, we present regime-based and phenomenological-related forecast performance results for WFIP 1. These performance metrics suggest future research pathways that will facilitate improvements in operational wind power forecasts.

  11. On the Fast Magnetic Rotator Regime of Stellar Winds

    CERN Document Server

    Johnstone, C P

    2016-01-01

    Aims: We study the acceleration of the stellar winds of rapidly rotating low mass stars and the transition between the slow magnetic rotator and fast magnetic rotator regimes. We aim to understand the properties of stellar winds in the fast magnetic rotator regime and the effects of magneto-centrifugal forces on wind speeds and mass loss rates. Methods: We extend the solar wind model of Johnstone et al. (2015b) to 1D magnetohydrodynamic (MHD) simulations of the winds of rotating stars. We test two assumptions for how to scale the wind temperature to other stars and assume the mass loss rate scales as Mdot ~ Rstar^2 OmegaStar^1.33 Mstar^-3.36, in the unsaturated regime, as estimated by Johnstone et al. (2015a). Results: For 1.0 Msun stars, the winds can be accelerated to several thousand km/s, and the effects of magneto-centrifugal forces are much weaker for lower mass stars. We find that the different assumptions for how to scale the wind temperature to other stars lead to significantly different mass loss ra...

  12. Unsustainable Groundwater Exploitation and Stochastic Regime Shifts: Converging Management Constraints

    Science.gov (United States)

    Rao, Suresh; Park, Jeryang

    2014-05-01

    Increasing water security concerns arise from projected increases in competing freshwater demands, resulting from rapid urbanization, growing affluent population, and the need for increased production of food and bio-energy. These global trends in concert with the convergence of three groups of threats are likely to exacerbate freshwater security issues: (1) increasing dependency on effectively non-renewable groundwater ("peak water"); (2) increasing groundwater quality impairment("land-use intensification") from larger contaminant loads delivered from the vadose zone and surface water; and (3) increasing uncertainties in groundwater demand/supply from climate change ("stochastic risks"). Here, we present a conceptual framework for exploring water security threats, with a consideration of aquifers as complex hydrological systems with two stable states. Regime shifts in groundwater pumping -- from "sufficient" to "insufficient" -- result from changes in both internal system dynamics and external forcing from stochastic divers (non-stationary demands, hydro-climatic patterns). Examples from recent related work, in groundwater and surface water systems and ecosystems, are briefly reviewed as a prelude to presentation of model simulations of hypothetical scenarios of regime-shifts (tipping points) involving groundwater quantity and quality constraints. In addition to three types of widely recognized tipping points, we introduce a new type, stochastic tipping, that contributes to unexpected, undesirable regime shifts, resulting in inability to meet groundwater pumping needs, even when the perceived precariousness is small and the system is far from bifurcation point (deterministic tipping). Implications to sustainable groundwater management are discussed.

  13. Regime shifts, resilience and recovery of a cod stock

    DEFF Research Database (Denmark)

    Lindegren, Martin; Diekmann, Rabea; Möllmann, Christian

    2010-01-01

    In the North and Baltic seas Atlantic cod Gadus morhua stocks collapsed as part or one of the major factors inducing large-scale ecosystem regime shifts. Determining the relative contribution of overfishing and climate variability in causing these shifts has proven difficult. While facing similar...... of the local cod stock to environmental change. The recovery and healthy condition of the Sound cod stock illustrate the need for adaptive marine management strategies that maximize ecosystem resilience....... and development of the Sound ecosystem, specifically testing for the occurrence of regime shifts and their potential drivers. By comparing the ecosystem development of the Sound with the neighbouring North and Baltic seas, we were able to demonstrate the positive effect of the trawl fishing ban on the resilience......In the North and Baltic seas Atlantic cod Gadus morhua stocks collapsed as part or one of the major factors inducing large-scale ecosystem regime shifts. Determining the relative contribution of overfishing and climate variability in causing these shifts has proven difficult. While facing similar...

  14. Kolmogorov and scalar spectral regimes in numerical turbulence

    Science.gov (United States)

    Kerr, R. M.

    1985-01-01

    Velocity and passive-scalar spectra for turbulent fields generated by a forced three-dimensional simulation and Taylormicroscale Reynolds numbers up to 83 are shown to have distinct spectral regimes, including a Kolmogorov inertial subrange. Both one- and three-dimensional spectra are shown for comparison with experiment and theory, respectively. When normalized by the Kolmogorov dissipation scales velocity spectra collapse to a single curve and a high-wavenumber bulge is seen. The bulge leads to an artificially high Kolmogorov constant, but is consistent with recent measurements of the velocity spectrum in the dissipation regime and the velocity-derivative skewness. Scalar spectra, when normalized by the Oboukov-Corrsin scales, collapse to curves which depend only on Prandtl number and show a universal inertial-convective subrange, independent of Prandtl number. When normalized by the Batchelor scales, the scalar spectra show a universal dissipation regime which is independent of Prandtl numbers from 0.1 to 1.0. The time development of velocity spectra is illustrated by energy-transfer spectra in which distinct pulses propagate to high wavenumbers.

  15. Idiosyncratic responses of high Arctic plants to changing snow regimes.

    Science.gov (United States)

    Rumpf, Sabine B; Semenchuk, Philipp R; Dullinger, Stefan; Cooper, Elisabeth J

    2014-01-01

    The Arctic is one of the ecosystems most affected by climate change; in particular, winter temperatures and precipitation are predicted to increase with consequent changes to snow cover depth and duration. Whether the snow-free period will be shortened or prolonged depends on the extent and temporal patterns of the temperature and precipitation rise; resulting changes will likely affect plant growth with cascading effects throughout the ecosystem. We experimentally manipulated snow regimes using snow fences and shoveling and assessed aboveground size of eight common high arctic plant species weekly throughout the summer. We demonstrated that plant growth responded to snow regime, and that air temperature sum during the snow free period was the best predictor for plant size. The majority of our studied species showed periodic growth; increases in plant size stopped after certain cumulative temperatures were obtained. Plants in early snow-free treatments without additional spring warming were smaller than controls. Response to deeper snow with later melt-out varied between species and categorizing responses by growth forms or habitat associations did not reveal generic trends. We therefore stress the importance of examining responses at the species level, since generalized predictions of aboveground growth responses to changing snow regimes cannot be made.

  16. Idiosyncratic responses of high Arctic plants to changing snow regimes.

    Directory of Open Access Journals (Sweden)

    Sabine B Rumpf

    Full Text Available The Arctic is one of the ecosystems most affected by climate change; in particular, winter temperatures and precipitation are predicted to increase with consequent changes to snow cover depth and duration. Whether the snow-free period will be shortened or prolonged depends on the extent and temporal patterns of the temperature and precipitation rise; resulting changes will likely affect plant growth with cascading effects throughout the ecosystem. We experimentally manipulated snow regimes using snow fences and shoveling and assessed aboveground size of eight common high arctic plant species weekly throughout the summer. We demonstrated that plant growth responded to snow regime, and that air temperature sum during the snow free period was the best predictor for plant size. The majority of our studied species showed periodic growth; increases in plant size stopped after certain cumulative temperatures were obtained. Plants in early snow-free treatments without additional spring warming were smaller than controls. Response to deeper snow with later melt-out varied between species and categorizing responses by growth forms or habitat associations did not reveal generic trends. We therefore stress the importance of examining responses at the species level, since generalized predictions of aboveground growth responses to changing snow regimes cannot be made.

  17. Socioecological regime shifts in the setting of complex social interactions

    Science.gov (United States)

    Sugiarto, Hendrik Santoso; Chung, Ning Ning; Lai, Choy Heng; Chew, Lock Yue

    2015-06-01

    The coupling between social and ecological system has become more ubiquitous and predominant in the current era. The strong interaction between these systems can bring about regime shifts which in the extreme can lead to the collapse of social cooperation and the extinction of ecological resources. In this paper, we study the occurrence of such regime shifts in the context of a coupled social-ecological system where social cooperation is established by means of sanction that punishes local selfish act and promotes norms that prescribe nonexcessive resource extraction. In particular, we investigate the role of social networks on social-ecological regimes shift and the corresponding hysteresis effects caused by the local ostracism mechanism under different social and ecological parameters. Our results show that a lowering of network degree reduces the hysteresis effect and also alters the tipping point, which is duly verified by our numerical results and analytical estimation. Interestingly, the hysteresis effect is found to be stronger in scale-free network in comparison with random network even when both networks have the same average degree. These results provide deeper insights into the resilience of these systems, and can have important implications on the management of coupled social-ecological systems with complex social interactions.

  18. Immunological responses elicited by different infection regimes with Strongyloides ratti.

    Directory of Open Access Journals (Sweden)

    Steve Paterson

    Full Text Available Nematode infections are a ubiquitous feature of vertebrate life. In nature, such nematode infections are acquired by continued exposure to infective stages over a prolonged period of time. By contrast, experimental laboratory infections are typically induced by the administration of a single (and often large dose of infective stages. Previous work has shown that the size of an infection dose can have significant effects on anti-nematode immune responses. Here we investigated the effect of different infection regimes of Strongyloides ratti, comparing single and repeated dose infections, on the host immune response that was elicited. We considered and compared infections of the same size, but administered in different ways. We considered infection size in two ways: the maximum dose of worms administered and the cumulative worm exposure time. We found that both infection regimes resulted in Th2-type immune response, characterised by IL4 and IL13 produced by S. ratti stimulated mesenteric lymph node cells, anti-S. ratti IgG(1 and intestinal rat mast cell protease II (RMCPII production. We observed some small quantitative immunological differences between different infection regimes, in which the concentration of IL4, IL13, anti-S. ratti IgG(1 and IgG(2a and RMCPII were affected. However, these differences were quantitatively relatively modest compared with the temporal dynamics of the anti-S. ratti immune response as a whole.

  19. Ecological forecasting in the presence of abrupt regime shifts

    Science.gov (United States)

    Dippner, Joachim W.; Kröncke, Ingrid

    2015-10-01

    Regime shifts may cause an intrinsic decrease in the potential predictability of marine ecosystems. In such cases, forecasts of biological variables fail. To improve prediction of long-term variability in environmental variables, we constructed a multivariate climate index and applied it to forecast ecological time series. The concept is demonstrated herein using climate and macrozoobenthos data from the southern North Sea. Special emphasis is given to the influence of selection of length of fitting period to the quality of forecast skill especially in the presence of regime shifts. Our results indicate that the performance of multivariate predictors in biological forecasts is much better than that of single large-scale climate indices, especially in the presence of regime shifts. The approach used to develop the index is generally applicable to all geographical regions in the world and to all areas of marine biology, from the species level up to biodiversity. Such forecasts are of vital interest for practical aspects of the sustainable management of marine ecosystems and the conservation of ecosystem goods and services.

  20. He-Accreting WDs: accretion regimes and final outcomes

    CERN Document Server

    Piersanti, L; Yungelson, L R

    2014-01-01

    The behaviour of carbon-oxygen white dwarfs (WDs) subject to direct helium accretion is extensively studied. We aim to analyze the thermal response of the accreting WD to mass deposition at different time scales. The analysis has been performed for initial WDs masses and accretion rates in the range (0.60 - 1.02) Msun and 1.e-9 - 1.e-5 Msun/yr, respectively. Thermal regimes in the parameters space M_{WD} - dot{M}_{He}, leading to formation of red-giant-like structure, steady burning of He, mild, strong and dynamical flashes have been identified and the transition between those regimes has been studied in detail. In particular, the physical properties of WDs experiencing the He-flash accretion regime have been investigated in order to determine the mass retention efficiency as a function of the accretor total mass and accretion rate. We also discuss to what extent the building-up of a He-rich layer via H-burning could be described according to the behaviour of models accreting He-rich matter directly. Polynomi...

  1. Intermittency of rheological regimes in uniform liquid-granular flows.

    Science.gov (United States)

    Armanini, Aronne; Larcher, Michele; Fraccarollo, Luigi

    2009-05-01

    We present a detailed analysis of a free surface-saturated liquid-granular mixture flowing over a static loose bed of grains, where the coexistence of layers dominated by collisional and frictional interactions among particles was observed. Kinetic theory was applied to the flow described above and it proved suitable for describing a realistic behavior of the collisional layers, although it failed to interpret the regions of the flow domain dominated by the frictional contacts. The paper provides a conceptual scheme with which to overcome this problem by focusing on the mechanisms governing the transition from the frictional to the collisional regime. In particular we observed that in highly concentrated flows the transition layer exhibits a typical intermittency of the dominating rheological regime, switching alternately from the frictional to the collisional one. By filtering the velocity signal, we introduced an intermittency function that made it possible to extend the validity of the equations derived from dense gas analogy, typical of the collisional regimes, also in the intermittent phase of the flow. Owing to the small values of the Stokes number, in the application of the kinetic theory we accounted for the possible variation of the elastic restitution coefficient along the flow depth. PMID:19518448

  2. British Columbia's new coalbed methane royalty regime

    Energy Technology Data Exchange (ETDEWEB)

    Molinski, D. [British Columbia Ministry of Energy and Mines, Victoria, BC (Canada). Energy and Minerals Div.

    2002-07-01

    The British Columbia Ministry of Energy and Mines is promoting the development of the coalbed methane (CBM) industry in the province in order to make CBM a viable and competitive investment option for industry. It is establishing a regulatory and fiscal regime for CBM development. Issues of concern regarding CBM development include water production, gas production rates, well numbers, and marginal economics. The features of the CBM royalty regime include a new producer cost of service allowance, the creation of a CBM royalty tax bank to collect excess PCOS allowances, and a royalty tax credit for wells drilled by the end of February, 2004. The marginal well adjustment factor threshold has been raised from 180 mcf per day to 600 mcf per day for CBM only. It was noted that royalties will probably not be payable for several years following the first commercial well because royalties are very depending on capital and operating costs, local infrastructure and price. Royalty regimes cannot save CBM from low gas prices, poor resources or economics. 2 figs.

  3. Spray structure as generated under homogeneous flash boiling nucleation regime

    International Nuclear Information System (INIS)

    We show the effect of the initial pressure and temperature on the spatial distribution of droplets size and their velocity profile inside a spray cloud that is generated by a flash boiling mechanism under homogeneous nucleation regime. We used TSI's Phase Doppler Particle Analyzer (PDPA) to characterize the spray. We conclude that the homogeneous nucleation process is strongly affected by the initial liquid temperature while the initial pressure has only a minor effect. The spray shape is not affected by temperature or pressure under homogeneous nucleation regime. We noted that the only visible effect is in the spray opacity. Finally, homogeneous nucleation may be easily achieved by using a simple atomizer construction, and thus is potentially suitable for fuel injection systems in combustors and engines. - Highlights: • We study the characteristics of a spray that is generated by a flash boiling process. • In this study, the flash boiling process occurs under homogeneous nucleation regime. • We used Phase Doppler Particle Analyzer (PDPA) to characterize the spray. • The SMD has been found to be strongly affected by the initial liquid temperature. • Homogeneous nucleation may be easily achieved by using a simple atomizer unit

  4. Siberian Lena River hydrologic regime and recent change

    Science.gov (United States)

    Yang, Daqing; Kane, Douglas L.; Hinzman, Larry D.; Zhang, Xuebin; Zhang, Tingjun; Ye, Hengchun

    2002-12-01

    The long-term (1935-1999) monthly records of temperature, precipitation, stream flow, river ice thickness, and active layer depth have been analyzed in this study to examine Lena River hydrologic regime and recent change. Remarkable hydrologic changes have been identified in this study. During the cold season (October-April), significant increases (25-90%) in stream flow and decrease in river ice thickness have been found due to warming in Siberia. In the snowmelt period (May-June), strong warming in spring leads to an advance of snowmelt season into late May and results in a lower daily maximum discharge in June. During summer months (July-September) the changes in stream flow hydrology are less significant in comparison to those for winter and spring seasons. A slight stream flow increase is discovered for both July and August, mainly owing to precipitation increase in May and June. Discharge in September has a slight downward trend due to precipitation decrease and temperature increase in August. The magnitudes of changes in stream flow and river ice thickness identified in this study are large enough to alter the hydrologic regime. Investigation into the hydrologic response of the Lena River to climate change and variation reveals strong linkages of stream flow with temperature and precipitation. We therefore believe that Lena River hydrologic regime changes are mainly the consequence of recent climate warming over Siberia and also closely related to changes in permafrost condition.

  5. Perspective: Single polymer mechanics across the force regimes

    Science.gov (United States)

    Saleh, Omar A.

    2015-05-01

    I review theoretical and experimental results on the force-extension response of single polymers, with a focus on scaling pictures of low-force elastic regimes, and recent measurements of synthetic and biological chains that explore those regimes. The mechanical response of single polymers is an old theoretical problem whose exploration was instigated by the curious thermomechanical behavior of rubber. Up until the 1990s, the main utility of those calculations was to explain bulk material mechanics. However, in that decade, it became possible to directly test the calculations through high-precision single-chain stretching experiments (i.e., force spectroscopy). I present five major single-chain elasticity models, including scaling results based on blob-chain models, along with analytic results based on linear response theory, and those based on freely jointed chain or worm-like chain structure. Each model is discussed in terms of the regime of force for which it holds, along with the status of its rigorous assessment with experiment. Finally, I show how the experiments can provide new insight into polymer structure itself, with particular emphasis on polyelectrolytes.

  6. Global impacts of the 1980s regime shift.

    Science.gov (United States)

    Reid, Philip C; Hari, Renata E; Beaugrand, Grégory; Livingstone, David M; Marty, Christoph; Straile, Dietmar; Barichivich, Jonathan; Goberville, Eric; Adrian, Rita; Aono, Yasuyuki; Brown, Ross; Foster, James; Groisman, Pavel; Hélaouët, Pierre; Hsu, Huang-Hsiung; Kirby, Richard; Knight, Jeff; Kraberg, Alexandra; Li, Jianping; Lo, Tzu-Ting; Myneni, Ranga B; North, Ryan P; Pounds, J Alan; Sparks, Tim; Stübi, René; Tian, Yongjun; Wiltshire, Karen H; Xiao, Dong; Zhu, Zaichun

    2016-02-01

    Despite evidence from a number of Earth systems that abrupt temporal changes known as regime shifts are important, their nature, scale and mechanisms remain poorly documented and understood. Applying principal component analysis, change-point analysis and a sequential t-test analysis of regime shifts to 72 time series, we confirm that the 1980s regime shift represented a major change in the Earth's biophysical systems from the upper atmosphere to the depths of the ocean and from the Arctic to the Antarctic, and occurred at slightly different times around the world. Using historical climate model simulations from the Coupled Model Intercomparison Project Phase 5 (CMIP5) and statistical modelling of historical temperatures, we then demonstrate that this event was triggered by rapid global warming from anthropogenic plus natural forcing, the latter associated with the recovery from the El Chichón volcanic eruption. The shift in temperature that occurred at this time is hypothesized as the main forcing for a cascade of abrupt environmental changes. Within the context of the last century or more, the 1980s event was unique in terms of its global scope and scale; our observed consequences imply that if unavoidable natural events such as major volcanic eruptions interact with anthropogenic warming unforeseen multiplier effects may occur. PMID:26598217

  7. Soil water regime under homogeneous eucalyptus and pine forests

    International Nuclear Information System (INIS)

    Measurement of precipitation and monthly soil water content during two consecutive years, in 6-year old plantations of eucalypt and pine, and also in an open plot containing natural herbaceous vegetation, were used to compare the soil water regime of these vegetation covers. Precipitation was measured in the open plot with a recording and a non-recording rain gage. Soil water was assessed by the neutron scattering technique to a depth of 1,80 meters. Results indicate that there was, in general, water available in the soil over the entire period of study in all three vegetation conditions. The annual range of soil water in eucalypt, pine, and in natural herbaceous vegetation was essentially similar. The analysis of the average soil water regime showed that the soil under herbaceous vegetation was, generally, more umid than the soil under eucalypt and pine during the period of soil water recharge (September through February); during the period of soil water depletion, the opposite was true. Collectively, the results permit the conclusion that there were no adverse effects on the soil water regime which could be ascribed to reflorestation with eucalypt or pine, as compared with that observed for the natural herbaceous vegetation

  8. Production Regimes for Self-Interacting Dark Matter

    CERN Document Server

    Bernal, Nicolas; Garcia-Cely, Camilo; Hambye, Thomas; Zaldivar, Bryan

    2015-01-01

    In the context of Self-Interacting Dark Matter as a solution for the small-scale structure problems, we consider the possibility that Dark Matter could have been produced without being in thermal equilibrium with the Standard Model bath. We discuss one by one the following various dark matter production regimes of this kind: freeze-in, reannihilation and dark freeze-out. We exemplify how these mechanisms work in the context of the particularly simple Hidden Vector Dark Matter model. In contrast to scenarios where there is thermal equilibrium with the Standard Model bath, we find two regimes which can easily satisfy all the laboratory and cosmological constraints. These are dark freeze-out with 3-to-2 annihilations and freeze-in via a light mediator. In the first regime, different temperatures in the visible and the Dark Matter sectors allow us to avoid the constraints coming from cosmic structure formation as well as the use of non-perturbative couplings to reproduce the observed relic density. For the second...

  9. Interannual variability of snow and fluvial regimes in Andorra

    Science.gov (United States)

    Pesado, Cristina; Riba, Sergi; Pons, Marc; Lopez-Moreno, Juan Ignacio

    2016-04-01

    Highlands in Andorra are snow-dominated areas during all the winter and most of the spring season. Interannual snow variability in these areas has a strong and straight influence on the amount and seasonality of river regimes at the bottom of the valley where most of the population and water requirements are concentrated. The present study analyzes the temporal and spatial variability of the fluvial regimes in Andorra and seeks to understand the interplay of different topographic and climatic variables on this variability. For example, in mountainous regions temperature determines the state of precipitation and this state can significantly affect runoff formation. The interannual temporal and spatial variability of temperatures, pluviometry and different snow indices such as snow heights and days with snow on the ground has been studied for the last decade and correlated with the fluvial dynamics and its variability using discharge measurements. This study focus especially in the assessment of the role of snow and its seasonality in the fluvial regime dynamics and the influence in the torrential flows and flood hazard. Flood hazard, force to take protection measures, which need information about flood frequency and magnitude. For this, flow instrumental series are used, but usually they do not consider phenomena like snowmelt. This study contributes intends to better understand the interplay between snow and fluvial dynamics and improve the assessment of the availability of water resources as well as the requirements in terms of protection measures.

  10. Fire regimes of quaking aspen in the Mountain West

    Science.gov (United States)

    Shinneman, Douglas J.; Baker, William L.; Rogers, Paul C.; Kulakowski, Dominik

    2013-01-01

    Quaking aspen (Populus tremuloides Michx.) is the most widespread tree species in North America, and it is found throughout much of the Mountain West (MW) across a broad range of bioclimatic regions. Aspen typically regenerates asexually and prolifically after fire, and due to its seral status in many western conifer forests, aspen is often considered dependent upon disturbance for persistence. In many landscapes, historical evidence for post-fire aspen establishment is clear, and following extended fire-free periods senescing or declining aspen overstories sometimes lack adequate regeneration and are succeeding to conifers. However, aspen also forms relatively stable stands that contain little or no evidence of historical fire. In fact, aspen woodlands range from highly fire-dependent, seral communities to relatively stable, self-replacing, non-seral communities that do not require fire for persistence. Given the broad geographic distribution of aspen, fire regimes in these forests likely co-vary spatially with changing community composition, landscape setting, and climate, and temporally with land use and climate – but relatively few studies have explicitly focused on these important spatiotemporal variations. Here we reviewed the literature to summarize aspen fire regimes in the western US and highlight knowledge gaps. We found that only about one-fourth of the 46 research papers assessed for this review could be considered fire history studies (in which mean fire intervals were calculated), and all but one of these were based primarily on data from fire-scarred conifers. Nearly half of the studies reported at least some evidence of persistent aspen in the absence of fire. We also found that large portions of the MW have had little or no aspen fire history research. As a result of this review, we put forth a classification framework for aspen that is defined by key fire regime parameters (fire severity and probability), and that reflects underlying biophysical

  11. Fire regime in a Mexican forest under indigenous resource management.

    Science.gov (United States)

    Fulé, Peter Z; Ramos-Gómez, Mauro; Cortés-Montaño, Citlali; Miller, Andrew M

    2011-04-01

    The Rarámuri (Tarahumara) people live in the mountains and canyons of the Sierra Madre Occidental of Chihuahua, Mexico. They base their subsistence on multiple-use strategies of their natural resources, including agriculture, pastoralism, and harvesting of native plants and wildlife. Pino Gordo is a Rarámuri settlement in a remote location where the forest has not been commercially logged. We reconstructed the forest fire regime from fire-scarred trees, measured the structure of the never-logged forest, and interviewed community members about fire use. Fire occurrence was consistent throughout the 19th and 20th centuries up to our fire scar collection in 2004. This is the least interrupted surface-fire regime reported to date in North America. Studies from other relict sites such as nature reserves in Mexico or the USA have all shown some recent alterations associated with industrialized society. At Pino Gordo, fires recurred frequently at the three study sites, with a composite mean fire interval of 1.9 years (all fires) to 7.6 years (fires scarring 25% or more of samples). Per-sample fire intervals averaged 10-14 years at the three sites. Approximately two-thirds of fires burned in the season of cambial dormancy, probably during the pre-monsoonal drought. Forests were dominated by pines and contained many large living trees and snags, in contrast to two nearby similar forests that have been logged. Community residents reported using fire for many purposes, consistent with previous literature on fire use by indigenous people. Pino Gordo is a valuable example of a continuing frequent-fire regime in a never-harvested forest. The Rarámuri people have actively conserved this forest through their traditional livelihood and management techniques, as opposed to logging the forest, and have also facilitated the fire regime by burning. The data contribute to a better understanding of the interactions of humans who live in pine forests and the fire regimes of these

  12. Hydrological regime modifications induced by climate change in Mediterranean area

    Science.gov (United States)

    Pumo, Dario; Caracciolo, Domenico; Viola, Francesco; Valerio Noto, Leonardo

    2015-04-01

    The knowledge of river flow regimes has a capital importance for a variety of practical applications, in water resource management, including optimal and sustainable use. Hydrological regime is highly dependent on climatic factors, among which the most important is surely the precipitation, in terms of frequency, seasonal distribution and intensity of rainfall events. The streamflow frequency regime of river basins are often summarized by flow duration curves (FDCs), that offer a simple and comprehensive graphical view of the overall historical variability associated with streamflow, and characterize the ability of the basin to provide flows of various magnitudes. Climate change is likely to lead shifts in the hydrological regime, and, consequently, in the FDCs. Staring from this premise, the primary objective of the present study is to explore the effects of potential climate changes on the hydrological regime of some small Mediterranean basins. To this aim it is here used a recent hydrological model, the ModABa model (MODel for Annual flow duration curves assessment in ephemeral small BAsins), for the probabilistic characterization of the daily streamflows in small catchments. The model has been calibrated and successively validated in a unique small catchment, where it has shown a satisfactory accuracy in reproducing the empirical FDC starting from easily derivable parameters arising from basic ecohydrological knowledge of the basin and commonly available climatic data such as daily precipitation and temperatures. Thus, this work also represents a first attempt to apply the ModABa to basins different from that used for its preliminary design in order to testing its generality. Different case studies are selected within the Sicily region; the model is first calibrated at the sites and then forced by future climatic scenarios, highlighting the principal differences emerging from the current scenario and future FDCs. The future climate scenarios are generated using

  13. Human impacts on river ice regime in the Carpathian Basin

    Science.gov (United States)

    Takács, Katalin; Nagy, Balázs; Kern, Zoltán

    2014-05-01

    River ice is a very important component of the cryosphere, and is especially sensitive to climatic variability. Historical records of appearance or disappearance and timing of ice phenomena are useful indicators for past climatic variations (Williams, 1970). Long-term observations of river ice freeze-up and break-up dates are available for many rivers in the temperate or cold region to detect and analyze the effects of climate change on river ice regime. The ice regime of natural rivers is influenced by climatic, hydrological and morphological factors. Regular ice phenomena observation mostly dates back to the 19th century. During this long-term observation period, the human interventions affecting the hydrological and morphological factors have become more and more intensive (Beltaos and Prowse, 2009). The anthropogenic effects, such as river regulation, hydropower use or water pollution causes different changes in river ice regime (Ashton, 1986). To decrease the occurrence of floods and control the water discharge, nowadays most of the rivers are regulated. River regulation changes the morphological parameters of the river bed: the aim is to create solid and equable bed size and stream gradient to prevent river ice congestion. For the satisfaction of increasing water demands hydropower is also used. River damming results a condition like a lake upstream to the barrage; the flow velocity and the turbulence are low, so this might be favourable for river ice appearance and freeze-up (Starosolsky, 1990). Water pollution affects ice regime in two ways; certain water contaminants change the physical characteristics of the water, e.g. lessens the freezing point of the water. Moreover the thermal stress effect of industrial cooling water and communal wastewater is also important; in winter these water sources are usually warmer, than the water body of the river. These interventions result different changes in the characteristic features of river ice regime. Selected

  14. Crop based climate regimes for energy saving in greenhouse cultivation

    Energy Technology Data Exchange (ETDEWEB)

    Koerner, O.

    2003-06-16

    Sustainability is one of the major aims in greenhouse horticulture. According to agreements between the Dutch grower association and the government, energy consumption and the use of chemical biocides have to be reduced. More advanced greenhouse technique is being developed to reach the target to decrease the energy efficiency-index by 65% between 1980 and 2010. However, this could also be achieved with existing technology by using more advanced climate regimes. The present thesis aimed at that, through designing and analysing climate regimes while employing existing climate control possibilities. Theoretical temperature and humidity regimes were designed to decrease energy consumption and a photosynthesis maximisation procedure was implemented to maximise growth. The basis for a crop gross photosynthesis model for control purposes was created. Crop photosynthesis models were evaluated at conditions expected to occur with more sustainable climate regimes. It was shown with experimental evidence that theoretical assumptions on the temperature - CO2 effects in a crop that are based on theoretically models scaling up leaf photosynthesis to the crop level are valid and that simplified existing models could be applied up to 28C. With higher temperatures new designs are needed and this can probably be achieved with an improved stomata-resistance model. The well known temperature integration principle was modified with two nested time-frames (24-hour and six days) and a temperature dose-response function. In a year round tomato cultivation, energy consumption was predicted to decrease with up to 9 % compared to regular temperature integration. The potential for energy saving with temperature integration is limited by humidity control when as usual fixed set points are maintained, because it counteracts temperature integration. Vents open at lower temperatures and heating is switched on at higher temperatures than required for optimal effects of temperature integration. A

  15. China and Nuclear Non-Proliferation Regime, 1964-1989

    International Nuclear Information System (INIS)

    The invention of nuclear weapons opened a new era for the history of human weaponry and warfare, and also reshaped international relations. As a consequence, a worldwide consensus has been gradually reached due to the destructive nature of nuclear weapons: since a world with nuclear weapons is extremely dangerous, all human beings must make coordinated effort to eliminate nuclear weapons completely. To achieve this goal, which is unrealistic for the time being, a step must be taken now to stop the proliferation of nuclear weapons and its technology. China became a nuclear power in 1964, and ever since, China’s attitude with the nuclear non-proliferation regime has been closely linking China’s core strategic interests with the stability of the world. The relationship between China and the nuclear non-proliferation regime is expounded in two stages during the Cold War era. From the early 1960s to late 1970s, China criticized the nuclear non-proliferation idea by arguing for a complete elimination of nuclear weapons by all nuclear powers. China criticized the Partial Test Ban Treaty (PTBT) and the Treaty on the Non-Proliferation of Nuclear Weapons (NPT), when it believed that both treaties aimed only for the existing nuclear powers to monopolize nuclear technology and power. Since the reforms began in the opening-up era in the 1980s, China became actively involved in participation in the nuclear non-proliferation regime, which not only changed China’s national identity but also readjusted China’s vision about its own national interest and the global security. China affirmed its rejection to nuclear proliferation and began to involve partly in nuclear non-proliferation regime. China joined the International Atomic Energy Agency in 1984. In 1988, China signed an agreement with the IAEA for the application of safeguards, and voluntarily placed its civilian nuclear facilities under the IAEA safeguards. However China maintained its resistance to the NPT. This paper

  16. Correlation Between Transient Regime and Steady-State Regime on Creep Crack Growth Behavior of Grade 91 Steel

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jae Young; Ekaputra, I. M. W.; Kim, Seon Jin [Pukyong National Univ., Busan (Korea, Republic of); Kim, Woo Gon; Kim, Eung Seon [KAERI, Daejeong (Korea, Republic of)

    2015-12-15

    A correlation between the transient regime and steady state regime on the creep crack growth (CCG) for Grade 91 steel, which is used as the structural material for the Gen-IV reactor systems, was investigated. A series of CCG tests were performed using 1/2' CT specimens under a constant applied load and at a constant temperature of 600 °C. The CCG rates for the transient and steady state regimes were obtained in terms of C* parameter. The transient CCG rate had a close correlation with the steady-state CCG rate, as the slope of the transient CCG data was very similar to that of the steady state data. The transient rate was slower by 5.6 times as compared to the steady state rate. It can be inferred that the steady state CCG rate, which is required for long-time tests, can be predicted from the transient CCG rate obtained from short-time tests.

  17. General Considerations about Matrimonial Regime under the Provisions of the New Romanian Civil Code

    Directory of Open Access Journals (Sweden)

    Nadia Cerasela ANITEI

    2011-12-01

    Full Text Available The provisions of art. 312 of the Civil Code establish: a legal system, that is the community property regime and two types of conventional regimes: the regime of separation of goods and the regime of conventional community (the latter includes conventional derogation from community property regime.Legal matrimonial regime includes assets acquired by each spouse during marriage, except property required by law, which represents each spouse’s own assets.Community legal regime will apply in all situations in which prospective spouses opt for separation of property regime or the regime of conventional community.Separation of property regime is characterized by the fact that each of the spouses is the exclusive owner of their current assets and of those acquired alone after the dissolution of marriage, for the adoption of this regime the spouses being forced to draw up an inventory of movable property belonging to each one at the contracting of marriage.Conventional community regime is applicable when by matrimonial agreement, it derogates from the provisions on legal community regime, and the matrimonial convention concluded in this case can narrow or broaden the community of goods.

  18. The world's non-proliferation regime in time

    International Nuclear Information System (INIS)

    The idea for a treaty to prevent the spread of nuclear weapons to more countries was supported unanimously by the UN General Assembly in 1961. The NPT permits the P-5 to have nuclear weapons. All other NPT signatories are 'non-nuclear-weapon States' who are prohibited from acquiring nuclear weapons. To gain their signatures, the NPT promises assistance to them in the peaceful uses of nuclear energy and negotiations toward nuclear disarmament. Besides the P-5, the treaty now has 184 countries that have promised not to have nuclear weapons and that have agreed to accept inspections by the IAEA to verify that they are carrying out their promises. However, India, Pakistan, and Israel refused to join the treaty, and the Democratic People's Republic of Korea (North Korea) withdrew from it. Of these four countries, only India and Pakistan have tested nuclear weapons. Israel and North Korea are assumed to have them. The non-proliferation regime today includes much more than the NPT. The IAEA standards for inspection were the next most important element. The IAEA inspection requirements negotiated in the early 1970s were shown to be inadequate by Iraq's success in hiding its nuclear-weapon efforts before and during the Gulf War of 1991. The Additional Protocol of 1997 is slowly replacing these requirements, but, as of December 2004, was in effect in only 62 NPT member countries. The regime includes the agreements creating nuclear-weapon free zones in Africa, Latin America, Southeast Asia, the South Pacific, and Mongolia. The countries that formed these zones are also members of the NPT. The regime includes suggestions for standards and financial assistance plus requirements for physical protection of nuclear material from theft by terrorists or others. These efforts range from the Convention on Physical Protection of Nuclear Material, to the technical assistance provided by the IAEA and some countries, to the financial assistance offered by the G-8 and some other IAEA

  19. Measurement of the fission cross section induced by fast neutrons of the {sup 232}Th/{sup 233}U nuclei within the innovating fuel cycles framework; Mesure de la section efficace de fission induite par neutrons rapides des noyaux {sup 232}Th/{sup 233}U dans le cadre des cycles de combustible innovants

    Energy Technology Data Exchange (ETDEWEB)

    Grosjean, C

    2005-03-15

    The thorium-U{sup 233} fuel cycle might provided safer and cleaner nuclear energy than the present Uranium/Pu fuelled reactors. Over the last 10 years, a vast campaign of measurements has been initiated to bring the precision of neutron data for the key nuclei (Th{sup 232}, Pa{sup 233} and U{sup 233}) at the level of those for the U-Pu cycle. This is the framework of these measurements, the energy dependent neutron induced fission cross section of Th{sup 232} and U{sup 233} has been measured from 1 to 7 MeV with a target accuracy lesser than 5 per cent. These measurements imply the accurate determination of the fission rate, the number of the target nuclei as well as the incident neutron flux impinging on the target, the latter has been obtained using the elastic scattering (n,p). The cross section of which is very well known in a large neutron energy domain ({approx} 0,5 % from 1 eV to 50 MeV) compared to the U{sup 235}(n,f) reaction. This technique has been applied for the first time to the Th{sup 232}(n,f) and U{sup 233}(n,f) cases. A Hauser-Feshbach statistical model has been developed. It consists of describing the different decay channels of the compound nucleus U{sup 234} from 0,01 to 10 MeV neutron energy. The parameters of this model were adjusted in order to reproduce the measured fission cross section of U{sup 233}. From these parameters, the cross sections from the following reactions could be extracted: inelastic scattering U{sup 233}(n,n'), radiative capture U{sup 233}(n,{gamma}) and U{sup 233}(n,2n). These cross sections are still difficult to measure by direct neutron reactions. The calculated values have allowed us to fill the lack of experimental data for the major fissile nucleus of the thorium cycle. (author)

  20. Technical efficiency under alternative environmental regulatory regimes: The case of Dutch horticulture

    NARCIS (Netherlands)

    Vlist, van der A.J.; Withagen, C.; Folmer, H.

    2007-01-01

    We consider the performance of small and medium sized enterprises in Dutch horticulture under different environmental policy regimes across time. We address the question whether technical performance differs under these alternative regulatory regimes to test Porter's hypothesis that stricter environ

  1. Technical efficiency under alternative environmental regulatory regimes : The case of Dutch horticulture

    NARCIS (Netherlands)

    van der Vlist, Arno J.; Withagen, Cees; Folmer, Henk

    2007-01-01

    We consider the performance of small and medium sized enterprises in Dutch horticulture under different environmental policy regimes across time. We address the question whether technical performance differs under these alternative regulatory regimes to test Porter's hypothesis that stricter environ

  2. Direct-contact condensation regime map for core makeup tank of passive reactors

    International Nuclear Information System (INIS)

    The condensation regime map in the core makeup tank of passive reactors is experimentally investigated. The condensation regimes identified through the experiments are divided into three distinct ones: sonic jet, subsonic jet, and steam cavity. The steam cavity regime is a unique regime of downward injection with the present geometry not previously observed in other experiments. The condensation regime map is constructed using Froude number and Jacob number. It turns out that the buoyancy force has a large influence on the regime transition because the regime map using the Froude number better fits data with different geometries than other dimensionless parameters. Simple correlations for the regime boundaries are proposed using the Froude number and the Jacob number

  3. A Safety-Case Regime for Commercial Human Spaceflight

    Science.gov (United States)

    Sgobba, T.; Trujillo, M.

    2012-01-01

    Currently the commercial human spaceflight community seems to be embracing the obsolete design principles of "fly-fix-fly", and betting on public acceptance of risks comparable to those of the early times of aviation industry. The nascent space tourism industry maintains that early safety regulations (apart public safety) would kill industry and that such regulations could be developed only later when substantial operational experience is gained. Truly, most of current commercial aviation safety regulations are based on prescriptive requirements (i.e. explicitly required design solution for an implicit goal), which have been incrementally developed over more than a half century of mass transportation by air, and cannot be in general directly applied to innovative systems. However modern complex safety-critical systems cannot risk catastrophic failures while their operational experience is being accumulated, for such reason they are developed through the so called safety-case regime. ESA is currently drafting a safety standard for its future human rated transportation systems that is based on such regime. Such standard can be easily tailored with few modifications and applied to the development of a sub-orbital commercial space vehicle. In any case, because the safety-case regime makes extensive use of generically formulated requirements, the support of skilled safety engineers fully integrated into the design team is required since the very beginning. Furthermore the safety certification team needs also to be experienced in the review of safety-case based designs. Finally a quantitative safety target needs to be included and verified as the ultimate "prove of goodness" of system design.

  4. Are there two regimes in strongly rotating turbulence?

    Science.gov (United States)

    Baqui, Yasir Bin; Davidson, P. A.; Ranjan, Avishek

    2016-04-01

    We describe numerical experiments of freely decaying, rapidly rotating turbulence in which the Rossby number varies from Ro = O(1) down to Ro ˜ 0.02. Our central premise is that there exists two distinct dynamical regimes; one for Ro > 0.3 → 0.4, which is typical of most laboratory experiments, and another corresponding to Ro 0.3 → 0.4 is reported in Baqui and Davidson ["A phenomenological theory of rotating turbulence," Phys. Fluids 27, 025107 (2015)] and is characterised by: (i) a growth of the parallel integral scale according to l|| ˜ l⊥Ωt; (ii) a dissipation law which is quite different from that predicted by weak-turbulence theories, specifically ɛ = βu3/l|| where the pre-factor β is a constant of order unity; and (iii) an inertial-range energy spectrum for both the parallel and perpendicular wavenumbers which scales as k-5/3, a scaling that has nothing to do with Kolmogorov's law in non-rotating turbulence. (Here, l|| is the integral length-scale parallel to the rotation vector Ω, l⊥ the integral length-scale perpendicular to Ω, u the integral scale velocity, and ɛ the viscous dissipation rate per unit mass.) By contrast, in the low-Ro regime, we find that l|| ˜ l⊥Ωt is replaced by l|| ˜ ut and there is no power-law scaling of the inertial range energy spectrum. While the dissipation law ɛ = βu3/l|| continues to hold at low Ro, at least approximately, the value of β now depends on Ro. It appears, therefore, that the dynamics of these two regimes are very different, and this may help explain why experimentalists and theoreticians sometimes present rather different interpretations of rotating turbulence.

  5. The superradiant instability regime of the spinning Kerr black hole

    OpenAIRE

    Hod, Shahar

    2016-01-01

    Spinning Kerr black holes are known to be superradiantly unstable to massive scalar perturbations. We here prove that the instability regime of the composed Kerr-black-hole-massive-scalar-field system is bounded from above by the dimensionless inequality $M\\mu < m \\cdot \\sqrt{{{2(1+\\gamma) (1-\\sqrt{1-\\gamma^2}) - \\gamma^2} \\over {4\\gamma^2}}}$, where $\\{\\mu,m\\}$ are respectively the proper mass and azimuthal harmonic index of the scalar field and $\\gamma\\equiv r_-/r_+$ is the dimensionless ra...

  6. Canada on course to introduce permissive assisted dying regime.

    Science.gov (United States)

    Schuklenk, Udo

    2016-08-01

    Canada's Supreme Court decided in February 2015 that the criminalisation of assisted dying in the country violates the country's citizens and residents constitutional rights. This paper reviews policy recommendations produced by a special expert advisory panel appointed by Canada's provinces and territories, where the responsibility for the provision of health care lies. It also reviews a similar document produced by a special federal parliamentary committee. Based on the review of these two milestone documents it is argued that a Canadian consensus seems to emerge that foreshadows a permissive regulatory regime in that country. PMID:27009981

  7. Variational Bayes for Regime-Switching Log-Normal Models

    Directory of Open Access Journals (Sweden)

    Hui Zhao

    2014-07-01

    Full Text Available The power of projection using divergence functions is a major theme in information geometry. One version of this is the variational Bayes (VB method. This paper looks at VB in the context of other projection-based methods in information geometry. It also describes how to apply VB to the regime-switching log-normal model and how it provides a computationally fast solution to quantify the uncertainty in the model specification. The results show that the method can recover exactly the model structure, gives the reasonable point estimates and is very computationally efficient. The potential problems of the method in quantifying the parameter uncertainty are discussed.

  8. Drainage vent systems: investigation and analysis of air pressure regime

    Energy Technology Data Exchange (ETDEWEB)

    Swaffield, J.A.; Jack, L.B. [Heriot-Watt University, Edinburgh (United Kingdom). Dept. of Building Engineering and Surveying

    1998-12-31

    Knowledge of the performance of building drainage vent systems and associated appliance trap seal loss and retention has developed in recent years due to extensive research into the generation and propagation of air pressure transients within drainage networks. This paper demonstrates how data gathered from experimental testing of several single stack systems, considering the influence of a wide range of parameters including stack diameter, roughness, height and applied water flow rate, can be used to provide generally applicable mathematical expressions which assist in determining the pressure regime present at critical points within such systems. (author)

  9. Crossflow and water banks in viscous dominant regimes of waterflooding

    DEFF Research Database (Denmark)

    Yuan, Hao; Zhang, Xuan; Shapiro, Alexander;

    2014-01-01

    profiles are more even and smoother in a communicating layer-cake reservoir than in a noncommunicating one. Water banks and transition zones may be observed. Analysis indicates that the phenomena are attributed to the enhanced crossflow due to large mobility ratios (water-oil). The mobility control......Understanding the crossflow in multilayered reservoirs is of great importance for designing mobility control methods for enhanced oil recovery. The authors reveal saturation profiles in stratified reservoirs to study the interlayer communication in the viscous dominant regime. The displacement...

  10. Defocusing regimes of nonlinear waves in media with negative dispersion

    DEFF Research Database (Denmark)

    Bergé, L.; Kuznetsov, E.A.; Juul Rasmussen, J.

    1996-01-01

    Defocusing regimes of quasimonochromatic waves governed by a nonlinear Schrodinger equation with mixed-sign dispersion are investigated. For a power-law nonlinearity, we show that localized solutions to this equation defined at the so-called critical dimension cannot collapse in finite time...... in the sense that their transverse (anomalously dispersing) and longitudinal (normally dispersing) extensions never vanish. Solutions defined at the supercritical dimension are proved to exhibit a nonvanishing mean longitudinal size, and cannot transversally collapse if they are assumed to shrink along each...

  11. Terahertz phase microscopy in the sub-wavelength regime

    Science.gov (United States)

    Yi, Minwoo; Lee, Kanghee; Song, Jin-Dong; Ahn, Jaewook

    2012-04-01

    Gouy phase shift is a well-known behavior that occurs when a propagating light is focused, but its behavior in the sub-wavelength confinement is not yet known. Here, we report the theoretical and experimental study of the aperture-size dependency of the Gouy phase shift in the sub-wavelength diffraction regime. In experiments carried out with laser-induced terahertz (THz) wave emission from various semiconductor apertures, we demonstrate the use of Guoy phase shit for sub-wavelength THz microscopy.

  12. Operating regimes of an unconventional radial pump stage

    Energy Technology Data Exchange (ETDEWEB)

    Gantar, T. [Turbomachinery Div., Envita d.o.o., Ljubljana (Slovenia); Sekavcnik, M. [Ljubljana Univ. (Slovenia). Faculty of Mechanical Engineering

    2007-06-15

    This paper presents some phenomena concerning the stability problem of the basic flow direction observed within the CFD analyses of an unconventional radial pump stage (RPS). In order to preclude defining the flow direction as a boundary condition, a closed hydraulic system was modelled to investigate the operating behaviour of the RPS and its energy characteristics. It was shown that the basic flow direction through the RPS is determined by the level of hydraulic losses within the closed hydraulic system. Combining the closed and open hydraulic system calculations, all possible operating regimes of the analysed RPS are presented by means of 4-quadrant chart. (orig.)

  13. Simulation of the Operation Regimes of a Welding Transformer

    Directory of Open Access Journals (Sweden)

    Lenuta Suciu

    2009-10-01

    Full Text Available The object of the paper is constituted by the simulation of the operation regimes of an electric transformer, using specialised simulation software, in order to determine the electromagnetic strains to which welding transformers are subjected to in the case of the faulty operation. The monitoring processes of the modern welding equipment impose the reduction of the risk of their breakdown, grace to the collection and processing of detailed information about the condition of the transformers with the help of specialised modelling software with finite element.

  14. Time-domain diagnostics in the picosecond regime

    International Nuclear Information System (INIS)

    The measurement of bunch length and longitudinal profile for microbunches of electrons and positrons in the ps and sub-ps regime will be a critical part of validating performance of proposed facilities. Data will be presented showing single-sweep streak camera results at σres ∼ 68 fs and projected synchroscan sweep resolution at σ ∼ 600 fs. Additionally, an rf cavity operating in a transverse magnetic mode has recently been shown to produce σres ∼ 280 fs when used with a low-emittance beam. The potential for dual-sweep streak work with σres < 1 ps on the fast axis is also described

  15. O regime de exigibilidade de caixa no IVA

    OpenAIRE

    Ferreira, Sónia Patrícia Duarte

    2011-01-01

    Mestrado em Contabilidade O Imposto sobre o Valor Acrescentado sucedeu ao imposto de transacções em 1986. Este imposto é um imposto indirecto, geral sobre o consumo e de matriz comunitária. Para que possamos ter noção de quando o imposto é devido e se torna exigível por parte do Estado, é essencial ter em conta as normas sobre o facto gerador e a exigibilidade do imposto. A Lei 15/2009, que entrou em vigor a 1 de Janeiro de 2009, consagra um novo regime de exigibilidade do IVA para a...

  16. A Second-order Impact Model for Forest Fire Regimes

    OpenAIRE

    Maggi, S. (Stefania); Rinaldi, S

    2006-01-01

    We present a very simple "impact" model for the description of forest fires and show that it can mimic the known characteristics of wild fire regimes in savannas, boreal forests, and Mediterranean forests. Moreover, the distribution of burned biomasses in model generated fires resemble those of burned areas in numerous large forests around the world. The model has also the merits of being the first second-order model for forest fires and the first example of the use of impact models in the st...

  17. A second-order impact model for forest fire regimes.

    Science.gov (United States)

    Maggi, Stefano; Rinaldi, Sergio

    2006-09-01

    We present a very simple "impact" model for the description of forest fires and show that it can mimic the known characteristics of wild fire regimes in savannas, boreal forests, and Mediterranean forests. Moreover, the distribution of burned biomasses in model generated fires resemble those of burned areas in numerous large forests around the world. The model has also the merits of being the first second-order model for forest fires and the first example of the use of impact models in the study of ecosystems. PMID:16723147

  18. Dynamics of aircraft exhaust plumes in the jet-regime

    Directory of Open Access Journals (Sweden)

    P. Fabian

    Full Text Available A computational model describing the two-dimensional, turbulent mixing of a single jet of exhaust gas from aircraft engines with the ambient atmosphere is presented. The underlying assumptions and governing equations are examined and supplemented by a discussion of analytical solutions. As an application, the jet dynamics of a B747-400 aircraft engine in cruise and its dependence on key parameters is investigated in detail. The computer code for this dynamical model is computationally fast and can easily be coupled to complex chemical and microphysical models in order to perform comprehensive studies of atmospheric effects from aircraft exhaust emissions in the jet regime.

  19. Climate-driven regime shift of a temperate marine ecosystem.

    Science.gov (United States)

    Wernberg, Thomas; Bennett, Scott; Babcock, Russell C; de Bettignies, Thibaut; Cure, Katherine; Depczynski, Martial; Dufois, Francois; Fromont, Jane; Fulton, Christopher J; Hovey, Renae K; Harvey, Euan S; Holmes, Thomas H; Kendrick, Gary A; Radford, Ben; Santana-Garcon, Julia; Saunders, Benjamin J; Smale, Dan A; Thomsen, Mads S; Tuckett, Chenae A; Tuya, Fernando; Vanderklift, Mathew A; Wilson, Shaun

    2016-07-01

    Ecosystem reconfigurations arising from climate-driven changes in species distributions are expected to have profound ecological, social, and economic implications. Here we reveal a rapid climate-driven regime shift of Australian temperate reef communities, which lost their defining kelp forests and became dominated by persistent seaweed turfs. After decades of ocean warming, extreme marine heat waves forced a 100-kilometer range contraction of extensive kelp forests and saw temperate species replaced by seaweeds, invertebrates, corals, and fishes characteristic of subtropical and tropical waters. This community-wide tropicalization fundamentally altered key ecological processes, suppressing the recovery of kelp forests. PMID:27387951

  20. Magnetic geometry and particle source drive of supersonic divertor regimes

    International Nuclear Information System (INIS)

    We present a comprehensive picture of the mechanisms driving the transition from subsonic to supersonic flows in tokamak plasmas. We demonstrate that supersonic parallel flows into the divertor volume are ubiquitous at low density and governed by the divertor magnetic geometry. As the density is increased, subsonic divertor plasmas are recovered. On detachment, we show the change in particle source can also drive the transition to a supersonic regime. The comprehensive theoretical analysis is completed by simulations in ITER geometry. Such results are essential in assessing the divertor performance and when interpreting measurements and experimental evidence. (technical note)

  1. A schematic model for QCD II finite temperature regime

    CERN Document Server

    Jesgarz, S; Hess, P O; Civitarese, O; Reboiro, M

    2003-01-01

    A schematic model for QCD, developed in a previous paper, is applied to calculate meson properties in the high temperature (up to 0.5 GeV) regime. It is a Lipkin model for quark-antiquark pairs coupled to gluon pairs of spin zero. The partition function is constructed with the obtained meson spectrum and several thermodynamical observables are calculated, like: the energy density, heat capacity, as well as relative production rates of mesons and absolute production rates for pions and kaons. The model predictions show a qualitative agreement with data. Based on these results we advocate the use of the model as a toy model for QCD.

  2. Chaotic scattering in the regime of weakly overlapping resonances.

    Science.gov (United States)

    Dietz, B; Friedrich, T; Harney, H L; Miski-Oglu, M; Richter, A; Schäfer, F; Weidenmüller, H A

    2008-11-01

    We measure the transmission and reflection amplitudes of microwaves in a resonator coupled to two antennas at room temperature in the regime of weakly overlapping resonances and in a frequency range of 3-16GHz . Below 10.1GHz the resonator simulates a chaotic quantum system. The distribution of the elements of the scattering matrix S is not Gaussian. The Fourier coefficients of S are used for a best fit of the autocorrelation function of S to a theoretical expression based on random-matrix theory. We find very good agreement below but not above 10.1GHz .

  3. Quantum regime of resonant-tunnelling diode oscillations

    International Nuclear Information System (INIS)

    Resonant-tunneling diode (RTD) is one of the first quantum devices. In contrast to devices settled on quantum dots and quantum threads, which works only at low temperatures, RTD can works in a wide range of temperatures from liquid-helium temperature till 100C. Also, RTD has one more feature, which makes this device attractive for use in integrated circuits-high operating frequency and, as a consequence, fast response. In this work we investigated free-running lasing of RTD in quantum regime.

  4. Ion holes in the hydrodynamic regime in ultracold neutral plasmas

    Energy Technology Data Exchange (ETDEWEB)

    McQuillen, P.; Castro, J.; Strickler, T.; Bradshaw, S. J.; Killian, T. C. [Department of Physics and Astronomy, Rice University, Houston, Texas 77005 (United States)

    2013-04-15

    We describe the creation of localized density perturbations, or ion holes, in an ultracold neutral plasma in the hydrodynamic regime, and show that the holes propagate at the local ion acoustic wave speed. We also observe the process of hole splitting, which results from the formation of a density depletion initially at rest in the plasma. One-dimensional, two-fluid hydrodynamic simulations describe the results well. Measurements of the ion velocity distribution also show the effects of the ion hole and confirm the hydrodynamic conditions in the plasma.

  5. Giant and tunable electric field enhancement in the terahertz regime.

    Science.gov (United States)

    Lu, Xiaoyuan; Wan, Rengang; Wang, Guoxi; Zhang, Tongyi; Zhang, Wenfu

    2014-11-01

    A novel array of slits design combining the nano-slit grating and dielectric-metal is proposed to obtain giant and tunable electric field enhancement in the terahertz regime. The maximum amplitude of electric field is more than 6000 times larger than that of the incident electric field. It is found that the enhancement depends primarily on the stripe and nano-slits width of grating, as well as the thickness of spacer layer. This property is particularly beneficial for the realization of ultra-sensitive nanoparticles detection and nonlinear optics in the terahertz range, such as the second harmonic generation (SHG).

  6. The Numerical Modeling of Transient Regimes of Diesel Generator Sets

    Directory of Open Access Journals (Sweden)

    Cristian Roman

    2010-07-01

    Full Text Available This paper deals with the numerical modeling of a diesel generator set used as amain energy source in isolated areas and as a back-up energy source in the case ofrenewable energy systems. The numerical models are developed using a Matlab/Simulinksoftware package and they prove to be a powerful tool for the computer aided design ofcomplex hybrid power systems. Several operation regimes of the equipment are studied.The numerical study is completed with experimental measurements on a Kipor type dieselelectricgenerator set.

  7. Intergenerational Justice Perceptions and the Role of Welfare Regimes

    DEFF Research Database (Denmark)

    Sabbagh, Clara; Vanhuysse, Pieter

    2010-01-01

    , different welfare regimes structure young people's perceptions of the justness of public resources transfers from young to elderly age-groups and (2) the perceived relative contributions and rewards of various age-groups. Thus we inquire about both the perceived support in principle and about the perceived......-statist' ideological frame (the endorsement of egalitarian redistribution and broad state responsibility for welfare provision and the attribution of social inequality to external causes), and negatively with a 'market-based' frame (individualism, a work ethic, and internal attribution). Regarding actual outcomes...

  8. Geometric Constraints from Subregion Duality Beyond the Classical Regime

    CERN Document Server

    Akers, Chris; Leichenauer, Stefan; Levine, Adam

    2016-01-01

    Subregion duality in AdS/CFT implies certain constraints on the geometry: entanglement wedges must contain causal wedges, and nested boundary regions must have nested entanglement wedges. We elucidate the logical connections between these statements and the Quantum Focussing Conjecture, Quantum Null Energy Condition, Boundary Causality Condition, and Averaged Null Energy Condition. Our analysis does not rely on the classical limit of bulk physics, but instead works to all orders in \\(G\\hbar \\sim 1/N\\). This constitutes a nontrivial check on the consistency of subregion duality, entanglement wedge reconstruction, and holographic entanglement entropy beyond the classical regime.

  9. Why fiscal regimes matter for fiscal sustainability analysis: an application to France

    OpenAIRE

    Aldama, Pierre; Creel, Jérôme

    2016-01-01

    This paper introduces a Regime-Switching Model-Based Sustainability test allowing for periodic (or local) violations of Bohn (1998, QJE)’s sustainability condition. We assume a Markov-switching fiscal policy rule whose parameters stochastically switch between sustainable and unsustainable regimes. We demonstrate that long-run fiscal sustainability not only depends on regime-specific feedback coefficients of the fiscal policy rule but also on the average durations of fiscal regimes. Evidence o...

  10. Testing the Existence of Ricardian or Non-Ricardian Regimes for CIS Countries

    Directory of Open Access Journals (Sweden)

    Gulcin Guresci PEHLIVAN

    2016-03-01

    Full Text Available It is important to determine the dominant fiscal regime in a country group for policy prevision. This paper examines whether the Ricardian fiscal regime or non-Ricardian fiscal regime is dominant in the Common Wealth of Independent States (CIS. We attempted to show that CIS’ behavior after the debt stock increase. Using panel data method, this paper finds that Ricardian regime dominates in Kyrgyz Republic, Russian Federation, Tajikistan, Uzbekistan, Moldova and Turkmenistan’s fiscal policies.

  11. Trends in the International Regime of Liability and Compensation for Oil Pollution Damage

    Institute of Scientific and Technical Information of China (English)

    张秋荣

    2001-01-01

    Since the entry into force of the International Convention on liability and compensation for oil spill damage, there have been many discussions on the improvement of this regime. Based on the existing tworegimes, the writer tried to analysis the advantages of the new regimes and foresee the trends of the international regime of liability and compensation for oil pollution damage.

  12. Poloidal potential in the low-collisionality regime in a nonaxisymmetric torus

    International Nuclear Information System (INIS)

    The poloidal potential is calculated numerically in the low-collisionality regime for nonaxisymmetric tori such as stellarators and bumpy tori. It is found that even fairly deep into the superbanana regime, the poloidal potential retains the simple azimuthal dependence of the plateau regime. 12 refs., 8 figs

  13. Numerical study of flame structure in the mild combustion regime

    Directory of Open Access Journals (Sweden)

    Mardani Amir

    2015-01-01

    Full Text Available In this paper, turbulent non-premixed CH4+H2 jet flame issuing into a hot and diluted co-flow air is studied numerically. This flame is under condition of the moderate or intense low-oxygen dilution (MILD combustion regime and related to published experimental data. The modelling is carried out using the EDC model to describe turbulence-chemistry interaction. The DRM-22 reduced mechanism and the GRI2.11 full mechanism are used to represent the chemical reactions of H2/methane jet flame. The flame structure for various O2 levels and jet Reynolds numbers are investigated. The results show that the flame entrainment increases by a decrease in O2 concentration at air side or jet Reynolds number. Local extinction is seen in the upstream and close to the fuel injection nozzle at the shear layer. It leads to the higher flame entertainment in MILD regime. The turbulence kinetic energy decay at centre line of jet decreases by an increase in O2 concentration at hot Co-flow. Also, increase in jet Reynolds or O2 level increases the mixing rate and rate of reactions.

  14. Approaches to defining reference regimes for river restoration planning

    Science.gov (United States)

    Beechie, T. J.

    2014-12-01

    Reference conditions or reference regimes can be defined using three general approaches, historical analysis, contemporary reference sites, and theoretical or empirical models. For large features (e.g., floodplain channels and ponds) historical data and maps are generally reliable. For smaller features (e.g., pools and riffles in small tributaries), field data from contemporary reference sites are a reasonable surrogate for historical data. Models are generally used for features that have no historical information or present day reference sites (e.g., beaver pond habitat). Each of these approaches contributes to a watershed-wide understanding of current biophysical conditions relative to potential conditions, which helps create not only a guiding vision for restoration, but also helps quantify and locate the largest or most important restoration opportunities. Common uses of geomorphic and biological reference conditions include identifying key areas for habitat protection or restoration, and informing the choice of restoration targets. Examples of use of each of these three approaches to define reference regimes in western USA illustrate how historical information and current research highlight key restoration opportunities, focus restoration effort in areas that can produce the largest ecological benefit, and contribute to estimating restoration potential and assessing likelihood of achieving restoration goals.

  15. Enforcing the climate regime: Game theory and the Marrakesh Accords

    International Nuclear Information System (INIS)

    The article reviews basic insights about compliance and ''hard'' enforcement that can be derived from various non-cooperative equilibrium concepts and evaluates the Marrakesh Accords in light of these insights. Five different notions of equilibrium are considered - the Nash equilibrium, the sub game perfect equilibrium, the re negotiation proof equilibrium, the coalition proof equilibrium and the perfect Bayesian equilibrium. These various types of equilibrium have number of implications for effective enforcement: 1. Consequences of non-compliance should be more than proportionate. 2. To be credible punishment needs to take place in the Pareto frontier, rather than by reversion to some suboptimal state. 3. An effective enforcement system must be able to curb collective as well as individual incentives to cheat. 4. A fully transparent enforcement regime could in fact turn out to be detrimental for compliance levels. It is concluded that constructing an effective system for ''hard'' enforcement of the Kyoto Protocol is a formidable task that has only partially been accomplished by the Marrakesh Accords. A possible explanation is that the design of a compliance system for the climate regime involved a careful balancing of the desire to minimise non-compliance against other important considerations. (Author)

  16. Two-fluid MHD Regime of Drift Wave Instability

    Science.gov (United States)

    Yang, Shang-Chuan; Zhu, Ping; Xie, Jin-Lin; Liu, Wan-Dong

    2015-11-01

    Drift wave instabilities contribute to the formation of edge turbulence and zonal flows, and thus are believed to play essential roles in the anomalous transport processes in tokamaks. Whereas drift waves are generally assumed to be local and electrostatic, experiments have often found regimes where the spatial scales and the magnetic components of drift waves approach those of magnetohydrodynamic (MHD) processes. In this work we study such a drift wave regime in a cylindrical magnetized plasma using a full two-fluid MHD model implemented in the NIMROD code. The linear dependency of growth rates on resistivity and the dispersion relation found in the NIMROD calculations qualitatively agree with theoretical analysis. As the azimuthal mode number increases, the drift modes become highly localized radially; however, unlike the conventional local approximation, the radial profile of the drift mode tends to shift toward the edge away from the center of the density gradient slope, suggesting the inhomogeneity of two-fluid effects. Supported by National Natural Science Foundation of China Grant 11275200 and National Magnetic Confinement Fusion Science Program of China Grant 2014GB124002.

  17. Differentially Rotating White Dwarfs I: Regimes of Internal Rotation

    CERN Document Server

    Ghosh, Pranab

    2016-01-01

    Most viable models of Type Ia supernovae (SN~Ia) require the thermonuclear explosion of a carbon/oxygen white dwarf that has evolved in a binary system. Rotation could be an important aspect of any model for SN~Ia, whether single or double degenerate, with the white dwarf mass at, below, or above the Chandrasekhar limit. {\\sl Differential rotation} is specifically invoked in attempts to account for the apparent excess mass in the super--Chandrasekhar events. Some earlier work has suggested that only uniform rotation is consistent with the expected mechanisms of angular momentum transport in white dwarfs, while others have found pronounced differential rotation. We show that if the baroclinic instability is active in degenerate matter and the effects of magnetic fields are neglected, both nearly-uniform and strongly-differential rotation are possible. We classify rotation regimes in terms of the Richardson number, Ri. At small values of Ri $\\leq$ 0.1, we find both the low-viscosity Zahn regime with a non-monot...

  18. Enforcing the climate regime: Game theory and the Marrakesh Accords

    Energy Technology Data Exchange (ETDEWEB)

    Hovi, Jon

    2002-07-01

    The article reviews basic insights about compliance and ''hard'' enforcement that can be derived from various non-cooperative equilibrium concepts and evaluates the Marrakesh Accords in light of these insights. Five different notions of equilibrium are considered - the Nash equilibrium, the sub game perfect equilibrium, the re negotiation proof equilibrium, the coalition proof equilibrium and the perfect Bayesian equilibrium. These various types of equilibrium have number of implications for effective enforcement: 1. Consequences of non-compliance should be more than proportionate. 2. To be credible punishment needs to take place in the Pareto frontier, rather than by reversion to some suboptimal state. 3. An effective enforcement system must be able to curb collective as well as individual incentives to cheat. 4. A fully transparent enforcement regime could in fact turn out to be detrimental for compliance levels. It is concluded that constructing an effective system for ''hard'' enforcement of the Kyoto Protocol is a formidable task that has only partially been accomplished by the Marrakesh Accords. A possible explanation is that the design of a compliance system for the climate regime involved a careful balancing of the desire to minimise non-compliance against other important considerations. (Author)

  19. Making pore choices: repeated regime shifts in stomatal ratio.

    Science.gov (United States)

    Muir, Christopher D

    2015-08-22

    Ecologically important traits do not evolve without limits. Instead, evolution is constrained by the set of available and viable phenotypes. In particular, natural selection may only favour a narrow range of adaptive optima constrained within selective regimes. Here, I integrate data with theory to test whether selection explains phenotypic constraint. A global database of 599 plant species from 94 families shows that stomatal ratio, a trait affecting photosynthesis and defence against pathogens, is highly constrained. Most plants have their stomata on the lower leaf surface (hypostomy), but species with half their stomata on each surface (amphistomy) form a distinct mode in the trait distribution. A model based on a trade-off between maximizing photosynthesis and a fitness cost of upper stomata predicts a limited number of adaptive solutions, leading to a multimodal trait distribution. Phylogenetic comparisons show that amphistomy is the most common among fast-growing species, supporting the view that CO2 diffusion is under strong selection. These results indicate that selective optima stay within a relatively stable set of selective regimes over macroevolutionary time. PMID:26269502

  20. Political Regime and Human Capital: A Cross-Country Analysis.

    Science.gov (United States)

    Klomp, Jeroen; de Haan, Jakob

    2013-03-01

    We examine the relationship between different dimensions of the political regime in place and human capital using a two-step structural equation model. In the first step, we employ factor analysis on 16 human capital indicators to construct two new human capital measures (basic and advanced human capital). In the second step, we estimate the impact of our political variables on human capital, using a cross-sectional structural model for some 100 countries. We conclude that democracy is positively related to basic human capital, while regime instability has a negative link with basic human capital. Governance has a positive relationship with advanced human capital, while government instability has a negative link with advanced human capital. Finally, we also find an indirect positive effect of governance and democracy on both types of human capital through their effect on income. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s11205-011-9983-6) contains supplementary material, which is available to authorized users.

  1. Impurity accumulation in plasma regimes with high energy confinement

    Science.gov (United States)

    Ran, L. B.; Roberts, D. E.; Yang, H. R.; Dodel, G.; Gentle, K.; Von Goeler, S.; Holzhauer, E.; Hübner, K.; Keilhacker, M.; Korotkov, A.; Luce, T. C.; Miura, Y.; Tsois, N.; Würz, H.; Fussmann, G.; Hofmann, J.; Janeschitz, G.; Krieger, K.; Müller, E. R.; Nolte, R.; Röhr, H.; Steuer, K. H.; Becker, G.; Bomba, B.; Bruhns, H.; Büchl, K.; Carlson, A.; Eberhagen, A.; Fahrbach, H.-U.; Gehre, O.; Gernhardt, J.; Giannone, L.; Von Gierke, G.; Glock, E.; Gruber, O.; Haas, G.; Herrmann, H.; Kaesdorf, S.; Karger, F.; Kaufmann, M.; Klüber, O.; Kornherr, M.; Lackner, K.; Lang, R.; Lee, P.; Lisitano, G.; Mast, F.; Mayer, H. M.; McCormick, K.; Meisel, D.; Mertens, V.; Murmann, H.; Neuhauser, J.; Niedermeyer, H.; Noterdaeme, J. M.; Poschenrieder, W.; Preis, R.; Rapp, H.; Rudyj, A.; Sandmann, W.; Schneider, F.; Schnider, U.; Siller, G.; Simmet, E.; Speth, E.; Söldner, F.; Stäbler, A.; Steinmetz, K.; Stroth, U.; Vollmer, O.; Zasche, D.

    1989-04-01

    Investigations of impurity accumulation phenomena in ASDEX are reviewed. There are four different operating regimes where pronounced accumulation is observed and these regimes are also characterized by improved energy confinement. In particular, medium-Z metallic ions are involved in accumulation processes whereas low-Z ions appear almost unaffected. The rapid accumulation observed in the case of metallic ions may be explained by neoclassical inward drifts if we assume that the anomalous diffusion is sufficiently suppressed, some indication of this being found from laser blow-off studies. The present results, however, can only be partly explained by neoclassical theory, according to which accumulation of low-Z impurities should also occur. The temporal behaviour of accumulation and the retarding effect of proton dilution for collision dominated transport are also discussed. Finally, we conclude that the full benefits of improved energy confinement can be achieved only if the impurity influxes are kept to a sufficiently low level. Expressed in terms of concentrations under low confinement conditions we have to postulate, for ASDEX, concentrations ≲ 10 -4 for metals and ≲ 2% for all light impurities.

  2. Hydroperiod regime controls the organization of plant species in wetlands.

    Science.gov (United States)

    Foti, Romano; del Jesus, Manuel; Rinaldo, Andrea; Rodriguez-Iturbe, Ignacio

    2012-11-27

    With urban, agricultural, and industrial needs growing throughout the past decades, wetland ecosystems have experienced profound changes. Most critically, the biodiversity of wetlands is intimately linked to its hydrologic dynamics, which in turn are being drastically altered by ongoing climate changes. Hydroperiod regimes, e.g., percentage of time a site is inundated, exert critical control in the creation of niches for different plant species in wetlands. However, the spatial signatures of the organization of plant species in wetlands and how the different drivers interact to yield such signatures are unknown. Focusing on Everglades National Park (ENP) in Florida, we show here that cluster sizes of each species follow a power law probability distribution and that such clusters have well-defined fractal characteristics. Moreover, we individuate and model those signatures via the interplay between global forcings arising from the hydroperiod regime and local controls exerted by neighboring vegetation. With power law clustering often associated with systems near critical transitions, our findings are highly relevant for the management of wetland ecosystems. In addition, our results show that changes in climate and land management have a quantifiable predictable impact on the type of vegetation and its spatial organization in wetlands.

  3. Modeling viscosity and diffusion of plasma mixtures across coupling regimes

    Science.gov (United States)

    Arnault, Philippe

    2014-10-01

    Viscosity and diffusion of plasma for pure elements and multicomponent mixtures are modeled from the high-temperature low-density weakly coupled regime to the low-temperature high-density strongly coupled regime. Thanks to an atom in jellium modeling, the effect of electron screening on the ion-ion interaction is incorporated through a self-consistent definition of the ionization. This defines an effective One Component Plasma, or an effective Binary Ionic Mixture, that is representative of the strength of the interaction. For the viscosity and the interdiffusion of mixtures, approximate kinetic expressions are supplemented by mixing laws applied to the excess viscosity and self-diffusion of pure elements. The comparisons with classical and quantum molecular dynamics results reveal deviations in the range 20--40% on average with almost no predictions further than a factor of 2 over many decades of variation. Applications in the inertial confinement fusion context could help in predicting the growth of hydrodynamic instabilities.

  4. Finite element modelling of the Harwell regional groundwater flow regime

    International Nuclear Information System (INIS)

    In assessing the feasibility of a geological disposal site for low and intermediate level radioactive wastes, a detailed knowledge of the hydrogeological system is essential because dissolution and transport of any disposed waste would be controlled ultimately by the rate and direction of groundwater movement. This report describes a case study of the use of a finite element computer program to model the groundwater flow of the Harwell region. The aim of the work was to produce a numerical model which calculated results that compared closely to the observed features of the groundwater flow regime. The model results will then provide information about the groundwater head distribution and flow pattern between the points of observation, and these results may be used in determining the nature of any future applied field studies. A secondary aim of the modelling process was to assess the usefulness of the computer program for modelling groundwater flow in a layered sedimentary environment. The groundwater flow regime of the Harwell region has been modelled using the two dimensional NAMMU finite element computer program which calculates the groundwater head distribution and resultant groundwater flow pattern. (author)

  5. Numerical simulation of dip-coating in the evaporative regime.

    Science.gov (United States)

    Dey, Mohar; Doumenc, Frédéric; Guerrier, Béatrice

    2016-02-01

    A hydrodynamic model is used for numerical simulations of a polymer solution in a dip-coating-like experiment. We focus on the regime of small capillary numbers where the liquid flow is driven by evaporation, in contrast to the well-known Landau-Levich regime dominated by viscous forces. Lubrication approximation is used to describe the flow in the liquid phase. Evaporation in stagnant air is considered (diffusion-limited evaporation), which results in a coupling between liquid and gas phases. Self-patterning due to the solutal Marangoni effect is observed for some ranges of the control parameters. We first investigate the effect of evaporation rate on the deposit morphology. Then the role of the spatial variations in the evaporative flux on the wavelength and mean thickness of the dried deposit is ascertained, by comparing the 2D and 1D diffusion models for the gas phase. Finally, for the very low substrate velocities, we discuss the relative importance of diffusive and advective components of the polymer flux, and consequences on the choice of the boundary conditions. PMID:26920522

  6. Regimes de financiamento, risco crescente do endividamento e fragilidade financeira

    Directory of Open Access Journals (Sweden)

    Gilberto Tadeu Lima

    2005-06-01

    Full Text Available Elabora-se um modelo macroeconômico de curto prazo na tradição pós-keynesiana, no qual a oferta de crédito é endógena e o grau de endividamento das firmas é explicitamente modelado. Relacionam-se as condições de vigência dos regimes minskyanos de financiamento - hedge, especulativo ou Ponzi - não somente ao grau de endividamento e à taxa de juros, mas, inclusive, aos parâmetros da função investimento desejado da firmas e à propensão a poupar dos capitalistas produtivos e financeiros.It is developed a short-run macromodel in the post-keynesian tradition, in which credit supply is endogenous and firms' debt position is explicitly modeled. The conditions under which each one of the minskyan financing regimes will prevail are related not only to the degree of indebtedness and the level of interest rate, but also to the parameters of firms' desired investment function and the saving propensity of productive and financial capitalists.

  7. The New Legal Regime on Minority Shareholder Protection in Albania

    Directory of Open Access Journals (Sweden)

    Jonida Rustemaj

    2012-10-01

    Full Text Available This article aims at introducing the main changes brought by the new Albanian Company Law on minority shareholders’ protection. Due to the harmonization of our legislation with the acqui, new pieces of laws were introduced in commercial law. In 2008 the new law “On entrepreneurs and commercial companies” was enacted. The latter introduced new practices and concepts, some of them not familiar to the Albanian legal system. I was motivated to write a paper on minority shareholders protection in order to emphasize the new regime and instruments of protection granted by the new laws. A matter which concerns investors and especially foreign ones is the protection of minority shareholders. This paper discusses the instruments of protection of minority shareholders bringing the novelties of the newly introduced laws because of the unclear regime under the repealed law using the analytical and comparative method. Few rights which were known by the former Albanian company law were usually compromised, but under the law in force, minorities are much more protected.Does the new law strengthen the position of such category of shareholders? What are the rights of minority shareholders conferred by the law? These and other questions will be addressed herein.

  8. Low-Energy QCD in the Delta Regime

    CERN Document Server

    Matzelle, Matthew E

    2015-01-01

    We investigate properties of low-energy QCD in a finite spatial volume, but with arbitrary temperature. In the limit of small temperature and small cube size compared to the pion Compton wavelength, Leutwyler has shown that the effective theory describing low-energy QCD reduces to that of quantum mechanics on the coset manifold, which is the so-called delta regime of chiral perturbation theory. We solve this quantum mechanics analytically for the case of a $U(1)_L \\times U(1)_R$ subgroup of chiral symmetry, and numerically for the case of $SU(2)_L \\times SU(2)_R$. We utilize the quantum mechanical spectrum to compute the mass gap and chiral condensate, and investigate symmetry restoration in a finite spatial volume as a function of temperature. Because we obtain the spectrum for non-zero values of the quark mass, we are able to interpolate between the rigid rotor limit, which emerges at vanishing quark mass, and the harmonic approximation, which is referred to as the p-regime. We find that the applicability o...

  9. The present status of the CTBT verification regime

    International Nuclear Information System (INIS)

    The Comprehensive nuclear-Test-Ban Treaty (CTBT) was opened for signature on September 24, 1996. As of November 17, 2006 the numbers of Signatories and Ratifications are 177 and 137 respectively. The Preparatory Commission for the CTBT Organization, which consists of Signatures, has been preparing for the verification regime in order to monitor compliance with the Treaty. With 10 years passage the International Monitoring System is switching from establishing to operating phase and has functioned effectively to detect nuclear explosions. On the other hand many issues has arisen in long pending of not entering into force, which was not supposed in early time; for example restructuring of the organization for conforming operational body and its nature and status and technology refreshment. Also data globally acquired are being used for civil and scientific applications and attempts are made with increasing interaction between the Organization, Signatories and scientific community. This paper presents an overview of status of the verification regime, discuss future course and issues, and also expresses JAEA's programme related to the CTBT. (author)

  10. Oscillations in the bistable regime of neuronal networks

    Science.gov (United States)

    Roxin, Alex; Compte, Albert

    2016-07-01

    Bistability between attracting fixed points in neuronal networks has been hypothesized to underlie persistent activity observed in several cortical areas during working memory tasks. In network models this kind of bistability arises due to strong recurrent excitation, sufficient to generate a state of high activity created in a saddle-node (SN) bifurcation. On the other hand, canonical network models of excitatory and inhibitory neurons (E-I networks) robustly produce oscillatory states via a Hopf (H) bifurcation due to the E-I loop. This mechanism for generating oscillations has been invoked to explain the emergence of brain rhythms in the β to γ bands. Although both bistability and oscillatory activity have been intensively studied in network models, there has not been much focus on the coincidence of the two. Here we show that when oscillations emerge in E-I networks in the bistable regime, their phenomenology can be explained to a large extent by considering coincident SN and H bifurcations, known as a codimension two Takens-Bogdanov bifurcation. In particular, we find that such oscillations are not composed of a stable limit cycle, but rather are due to noise-driven oscillatory fluctuations. Furthermore, oscillations in the bistable regime can, in principle, have arbitrarily low frequency.

  11. Testing for regime-switching CAPM on Zagreb Stock Exchange

    Directory of Open Access Journals (Sweden)

    Tihana Škrinjarić

    2014-12-01

    Full Text Available The standard Capital Asset Pricing Model assumes that a linear relationship exists between the risk (beta and the expected excess return of a stock. However, empirical findings have shown over the years that this relationship varies over time. Stock markets undergo phases of greater and smaller volatility in which beta varies accordingly (undergoes different regimes. Given that the Croatian capital market is still insufficiently investigated, the aim of this paper is to explore the possibility of a non-linear relationship between the stock risk and return. Linear and Markov-switching models (Hamilton 1989 are examined on the Zagreb Stock Exchange based on monthly data on 21 stocks, ranging from January 2005 to December 2013. In that way, investors can use the results based on the best model when making decisions about buying stocks. Since this is one of the first papers on regime-switching on the Croatian capital market, it will hopefully contribute to the existing literature on investing.

  12. Consequences of more extreme precipitation regimes for terrestrial ecosystems

    Energy Technology Data Exchange (ETDEWEB)

    Knapp, Alan [Colorado State University, Fort Collins; Beier, Claus [Riso National Laboratory, Roskilde, Denmark; Briske, David [Texas A& M University; Classen, Aimee T [ORNL; Luo, Yiqi [University of Oklahoma; Reichstein, Markus [Max Planck Institute for Biogeochemistry; Smith, Melinda D [Yale University; Smith, Stanley D [University of Nevada, Las Vegas; Bell, Jesse E [University of Oklahoma; Fay, Philip [ORNL; Heisler, Jana A [Colorado State University, Fort Collins; Leavitt, Steven W [unknown; Sherry, Rebecca [University of Oklahoma; Smith, Ben [unknown; Weng, Ensheng [University of Oklahoma, Norman; Norby, Richard J [ORNL

    2008-09-01

    Amplification of the hydrological cycle, as a consequence of global warming, is forecast to be manifest not only by alterations in total annual precipitation, but also through more extreme precipitation regimes characterized by larger rainfall events and more severe intervening drought periods. Based on past studies and theory, we present a conceptual framework for predicting the consequences of this projected change in intra-annual rainfall patterns for terrestrial ecosystems arrayed along a broad gradient in water availability. More extreme rainfall regimes are predicted to increase the occurrence of periodic soil water stress in mesic ecosystems due to prolonged dry periods between rainfall events. In contrast, xeric ecosystems may exhibit the opposite response because a shift to a greater proportion of rainfall delivered in large precipitation events will result in reduced proportional evaporative losses per storm event and greater soil water storage, alleviating soil water stress for longer periods of time. Hydric ecosystems may experience reduced periods of anoxia if intervals between rainfall events increase. This contingent effect of the overall soil water balance on ecosystem responses will likely cascade through all hierarchical levels of ecological processes and interact in ways currently unknown with related global change drivers such as elevated atmospheric temperatures and CO2 concentrations. Thus, multi-factor comparative experiments and systems modeling approaches are needed to more fully understand and forecast the potential ecological consequences of this underappreciated aspect of climate change.

  13. Transport in Porous Fins From Laminar to Turbulent Regime

    Science.gov (United States)

    Coletti, Filippo; Muramatsu, Kenshiro; Furciniti, Brian; Elkins, Chris; Eaton, John

    2012-11-01

    Lotus type porous metal has elongated pores of random size and spatial distribution but a common orientation. Sets of so-called lotus fins are obtained by slicing the metal into thin layers and stacking them in the flow path, forcing the fluid to pass through the pores. Lotus fins represent a promising alternative to metal foam heat exchangers, because they offer higher thermal conductivity and lower pressure drop. We have experimentally analyzed the fluid flow and heat transfer in lotus fins to determine their transport properties in a range of flow regimes. The investigated Reynolds numbers based on the pore diameter and inner velocity ranged from 100 to 4000. Three-dimensional mean velocity fields were obtained by magnetic resonance velocimetry performed on magnified replicas of the fins, allowing determination of the mechanical dispersion imposed by the random structure of the fins. Thermal measurements on non-conductive fins provided the global diffusivity coefficient, which accounts for molecular, mechanical and (at high Reynolds number) turbulent diffusion. The latter contribution was isolated and its relevance assessed as a function of the flow regime.

  14. Fano-Andreev effect in Quantum Dots in Kondo regime

    Science.gov (United States)

    Orellana, Pedro; Calle, Ana Maria; Pacheco, Monica; Apel, Victor

    In the present work, we investigate the transport through a T-shaped double quantum dot system coupled to two normal leads and to a superconducting lead. We study the role of the superconducting lead in the quantum interferometric features of the double quantum dot and by means of a slave boson mean field approximation at low temperature regime. We inquire into the influence of intradot interactions in the electronic properties of the system as well. Our results show that Fano resonances due to Andreev bound states are exhibited in the transmission from normal to normal lead as a consequence of quantum interference and proximity effect. This Fano effect produced by Andreev bound states in a side quantum dot was called Fano-Andreev effect, which remains valid even if the electron-electron interaction are taken into account, that is, the Fano-Andreev effect is robust against e-e interactions even in Kondo regime. We acknowledge the financial support from FONDECYT program Grants No. 3140053 and 11400571.

  15. A new fast reconnection model in a collisionless regime

    CERN Document Server

    Tsiklauri, David

    2008-01-01

    Based on the first principles (by balancing the advection with the electron pressure tensor in the generalised Ohm's law, and using the conservation of mass) a simple model of magnetic reconnection in a collisionless regime is formulated. In addition to its importance from the fundamental point of view, the collisionless reconnection model offers a much faster reconnection rate ($M_{c'less}={(d_i/2)}^{1/2}$) than Sweet-Parker's classical one ($M_{sp}=S^{-1/2}$). The width of the diffusion region (current sheet) in the collisionless regime is found to be $\\delta_{c'less}={(d_i/2)}^{1/2}L$, which is much larger than the Sweet-Parker width ($\\delta_{sp}=S^{-1/2}L$) for the space plasma conditions. Amongst other issues, this alleviates e.g. the problem of interpretation of solar flares by means of reconnection, as for the typical solar coronal parameters the obtained collisionless reconnection time can be $< 10$ minutes, as opposed to Sweet-Parker's equivalent value of $<$ year. The new theoretical reconnec...

  16. Nutrient regimes control phytoplankton ecophysiology in the South Atlantic

    Directory of Open Access Journals (Sweden)

    T. J. Browning

    2013-07-01

    Full Text Available Fast Repetition Rate fluorometry (FRRf measurements of phytoplankton photophysiology from an across-basin South Atlantic cruise (as part of the GEOTRACES programme characterized two dominant ecophysiological regimes which were interpreted on the basis of nutrient limitation. South of the South Subtropical Convergence (SSTC in the northern sub-Antarctic sector of the Antarctic Circumpolar Current (ACC in the Eastern Atlantic Basin, waters are characterized by elevated chlorophyll concentrations, a dominance by larger phytoplankton cells, and low apparent photochemical efficiency (Fv / Fm. Shipboard 24 h iron (Fe addition incubation experiments confirmed that Fe stress was primarily responsible for the low Fv / Fm, with Fe addition to these waters, either within the artificial bottle additions or naturally occurring downstream enrichment from Gough Island, significantly increasing Fv / Fm values. Satellite images suggest a broader region of enhanced chlorophyll concentrations around the SSTC in the Western Atlantic relative to the Eastern Atlantic: hypothesized to be a result of higher iron supply from the South American continent. To the north of the SSTC at the southern boundary of the South Atlantic Gyre, phytoplankton are characterized by high values of Fv / Fm which, coupled with the low macronutrient concentrations and increased presence of picocyanobacteria, are interpreted as conditions of Fe replete, balanced macronutrient-limited growth. Spatial correlation was found between Fv / Fm and Fe:nitrate ratios, supporting the suggestion that the relative supply ratios of these two nutrients can control patterns of limitation and consequently the ecophysiology of phytoplankton in subtropical gyre and ACC regimes.

  17. Oscillations in the bistable regime of neuronal networks.

    Science.gov (United States)

    Roxin, Alex; Compte, Albert

    2016-07-01

    Bistability between attracting fixed points in neuronal networks has been hypothesized to underlie persistent activity observed in several cortical areas during working memory tasks. In network models this kind of bistability arises due to strong recurrent excitation, sufficient to generate a state of high activity created in a saddle-node (SN) bifurcation. On the other hand, canonical network models of excitatory and inhibitory neurons (E-I networks) robustly produce oscillatory states via a Hopf (H) bifurcation due to the E-I loop. This mechanism for generating oscillations has been invoked to explain the emergence of brain rhythms in the β to γ bands. Although both bistability and oscillatory activity have been intensively studied in network models, there has not been much focus on the coincidence of the two. Here we show that when oscillations emerge in E-I networks in the bistable regime, their phenomenology can be explained to a large extent by considering coincident SN and H bifurcations, known as a codimension two Takens-Bogdanov bifurcation. In particular, we find that such oscillations are not composed of a stable limit cycle, but rather are due to noise-driven oscillatory fluctuations. Furthermore, oscillations in the bistable regime can, in principle, have arbitrarily low frequency.

  18. Institutional effectiveness in international regimes. An analysis of the effectiveness of the nuclear non-proliferation regime coping with the political malignity in the case of Iran

    International Nuclear Information System (INIS)

    Among the international security regimes, the Nuclear Non-Proliferation Regime has a prominent ranking due to the destructive power of the nuclear weapons over regional and global peace and stability. The NPT Regime has come across with two major challenges in the recent decade: North Korea and Iran. Contrary to North Korea, Iran is determined to stay as a state party to the Nuclear Non-Proliferation Treaty. The Regime still did not confirm the character and extent of Iranian nuclear program. The question of this study is ''why the processes of the NPT Regime cannot specify the nature and scope of Irans nuclear program?'' The three main the processes of the regime, which are the International Atomic Energy Agency (IAEA), the UN Security Council (UNSC) and the multilateral negotiations, are examined to determine the weaknesses of the regime. This study argues that the regime is modulated to cope with operational challenges and it remains relatively incompetent when a political challenge arises.

  19. The Kyoto protocol: assessment and perspectives. Towards a new regime up to the climate stake

    International Nuclear Information System (INIS)

    This report proposes an analysis within the context of transition of the climate regime from the 'before-2012' regime to the 'post-2020' regime. It first gives an overview of international stakes and context (lack of ambition for climate policy, perspective of an international agreement from 2020). Then, the authors recall the history and achievements of the Kyoto protocol which is the basis of the present climate policy regime. They propose an assessment of actions performed by countries during the first period of the protocol, and focus on the present climate regime elements which are to be safeguarded. They analyse the weaknesses of the present regime, and propose possible improvements for the future post-2020 climate regime

  20. World-Ecology and Ireland: The Neoliberal Ecological Regime

    Directory of Open Access Journals (Sweden)

    Sharae Deckard

    2016-03-01

    Full Text Available Since the collapse of the Celtic Tiger, the socio-economic particularity of neoliberal capitalism in its Irish manifestation has increasingly been critiqued, but little attention has been paid to neoliberalism as ecology within Ireland. This article conducts an exploratory survey of the characteristics of the Irish neoliberal ecological regime during and after the Celtic Tiger, identifying the opening of new commodity frontiers (such as fracking, water, agro-biotechnology, and biopharma constituted in the neoliberal drive to appropriate and financialize nature. I argue for the usefulness of applying not only the tools of world-systems analysis, but also Jason W. Moore’s world-ecological paradigm, to analysis of Ireland as a semi-periphery. What is crucial to a macro-ecological understanding of Ireland’s role in the neoliberal regime of the world-ecology is the inextricability of its financial role as a tax haven and secrecy jurisdiction zone from its environmental function as a semi-peripheral pollution and water haven. We can adapt Jason W. Moore’s slogan that “Wall Street…becomes a way of organizing all of nature, characterized by the financialization of any income-generating activity” (Moore 2011b: 39 to say that to say that the “IFSC is a way of organizing nature,” with pernicious consequences for water, energy, and food systems in Ireland. Financial service centers and pharmaceutical factories, plantations and cattle ranches, tax havens and pollution havens, empires and common markets are all forms of environment-making that constellate human relations and extra-human processes into new ecological regimes. More expansive, dialectical understandings of “ecology” as comprising the whole of socio-ecological relations within the capitalist world-ecology—from farming to pharma to financialization—are crucial to forming configurations of knowledge able not only to take account of Ireland’s role in the environmental

  1. Historical thermal regimes define limits to coral acclimatization.

    Science.gov (United States)

    Howells, Emily J; Berkelmans, Ray; van Oppen, Madeleine J H; Willis, Bette L; Bay, Line K

    2013-05-01

    Knowledge of the degree to which corals undergo physiological acclimatization or genetic adaptation in response to changes in their thermal environment is crucial to the success of coral reef conservation strategies. The potential of corals to acclimatize to temperatures exceeding historical thermal regimes was investigated by reciprocal transplantation of Acropora millepora colonies between the warm central and cool southern regions of the Great Barrier Reef (GBR) for a duration of 14 months. Colony fragments retained at native sites remained healthy, whereas transplanted fragments, although healthy over initial months when temperatures remained within native thermal regimes, subsequently bleached and suffered mortality during seasonal temperature extremes. Corals hosting Symbiodinium D transplanted to the southern GBR bleached in winter and the majority suffered whole (40%; n=20 colonies) or partial (50%) mortality at temperatures 1.1 degrees C below their 15-year native minimum. In contrast, corals hosting Symbiodinium C2 transplanted to the central GBR bleached in summer and suffered whole (50%; n=10 colonies) or partial (42%) mortality at temperatures 2.5 degrees C above their 15-year native maximum. During summer bleaching, the dominant Symbiodinium type changed from C2 to D within corals transplanted to the central GBR. Corals transplanted to the cooler, southern GBR grew 74-80% slower than corals at their native site, and only 50% of surviving colonies reproduced, at least partially because of cold water bleaching of transplants. Despite the absence of any visual signs of stress, corals transplanted to the warmer, central GBR grew 52-59% more slowly than corals at their native site before the summer bleaching (i.e., from autumn to spring). Allocation of energy to initial acclimatization or reproduction may explain this pattern, as the majority (65%) of transplants reproduced one month earlier than portions of the same colonies retained at the southern

  2. Babinet's principle in the Fresnel regime studied using ultrasound

    CERN Document Server

    Hitachi, Akira

    2009-01-01

    Babinet's principle in the Fresnel regime has been confirmed directly by observing ultrasound diffracted by a circular disk and an aperture of the same size. The amplitude and the phase of diffracted ultrasonic waves have been measured and a graphical treatment of the results is performed. It is also found that the wave without the diffracting objects is indeed 90 deg in phase behind the wave from the center of the zone system. This paradox has previously been regarded as a defect of Fresnel's theory. The 90 deg phase difference appears also in Fresnel-Kirchhoff diffraction, Rayleigh-Sommerfeld diffraction and even in the edge-diffracted approach by Young. The apparatus used is intended as a table-top instrument for the student laboratory in general science and engineering classes.

  3. The Legal Regime of the Right to Administrate Public Property

    Directory of Open Access Journals (Sweden)

    Vasilica Negruţ

    2014-05-01

    Full Text Available The traditional institutions for administrative law, public property and the public domain have been the subject of numerous specialized papers from the interwar period. After 1990, the two institutions were discussed in light of the new legislative rules. Within this article we propose to analyze, based on the distinction between the notions of public property and public domain, the legal regime of the right to administrate assets of public property. Is this a real right appropriate for public property or just a simple competence of administration and management of public domain assets? Analyzing and comparing the opinions, the arguments expressed by specialists and the current legislation in this area, we conclude that the administrative right is a real right suitable for public property.

  4. Gamma-ray Explosion in Multiple Compton Scattering Regime

    CERN Document Server

    Gong, Z; Shou, Y R; Qiao, B; Bulanov, S V; Esirkepov, T Zh; Bulanov, S S; Chen, C E; He, X T; Yan, X Q

    2016-01-01

    Gamma-ray explosion from near critical density (NCD) target irradiated by four symmetrical imploding laser pulses is numerically investigated. With peak intensities about $10^{23}$ W/cm$^2$, the laser pulses boost electron energy through direct laser acceleration, while pushing them inward with the ponderomotive force. After backscattering with counter-propagating laser, the accelerated electron will be trapped in the optical lattice or the electromagnetic standing waves (SW) created by the coherent overlapping of the laser pulses, and meanwhile emit gamma-ray photon in Multiple Compton Scattering regime, where electron acts as a medium to transfer energy from laser to gamma-ray. The energy conversion rate from laser pulses to gamma-ray can be as high as around 50\\%. It may become one of the most efficient gamma-ray sources in laboratory.

  5. Fluid mobility over corrugated surfaces in the Stokes regime

    Science.gov (United States)

    Shelley, S. R.; Smith, J. D.; Hibbins, A. P.; Sambles, J. R.; Horsley, S. A. R.

    2016-08-01

    An exact solution is found for laminar fluid flow along the grooves of a family of surfaces whose shape is given by the Lambert W-function. This simple solution allows for the slip length in the direction parallel to the grooves to be calculated exactly. With this analytical model, we establish the regime of validity for a previously untested perturbation theory intended for calculating the surface mobility tensor of arbitrary periodic surfaces, finding that it compares well to the exact expression for nearly all choices of parameters of the conformal map. To test this perturbation theory further, the mobility tensor is evaluated for a simple sinusoidal surface for flow both parallel and perpendicular to the grooves, finding that the perturbation theory is less accurate in the latter of these two cases.

  6. Nanowire-based thermoelectric ratchet in the hopping regime

    Science.gov (United States)

    Bosisio, Riccardo; Fleury, Geneviève; Pichard, Jean-Louis; Gorini, Cosimo

    2016-04-01

    We study a thermoelectric ratchet consisting of an array of disordered nanowires arranged in parallel on top of an insulating substrate and contacted asymmetrically to two electrodes. Transport is investigated in the Mott hopping regime, when localized electrons can propagate through the nanowires via thermally assisted hops. When the electronic temperature in the nanowires is different from the phononic one in the substrate, we show that a finite electrical current is generated even in the absence of driving forces between the electrodes. We discuss the device performance both as an energy harvester, when an excess heat from the substrate is converted into useful power, and as a refrigerator, when an external power is supplied to cool down the substrate.

  7. Assessment of Global Variability in UTBB MOSFETs in Subthreshold Regime

    Directory of Open Access Journals (Sweden)

    Sergej Makovejev

    2014-07-01

    Full Text Available The global variability of ultra-thin body and buried oxide (UTBB MOSFETs in subthreshold and off regimes of operation is analyzed. The variability of the off-state drain current, subthreshold slope, drain-induced barrier lowering (DIBL, gate leakage current, threshold voltage and their correlations are considered. Two threshold voltage extraction techniques were used. It is shown that the transconductance over drain current (gm/Id method is preferable for variability studies. It is demonstrated that the subthreshold drain current variability in short channel devices cannot be described by threshold voltage variability. It is suggested to include the effective body factor incorporating short channel effects in order to properly model the subthreshold drain current variability.

  8. First principles electron transport simulations in the Kondo regime

    Science.gov (United States)

    Rungger, Ivan; Radonjic, Milos; Appelt, Wilhelm; Chioncel, Liviu; Droghetti, Andrea

    When magnetic atoms, molecules or thin films are brought into contact with metals the electron-electron interaction leads to the appearance of the correlated Kondo state at low temperatures. In this talk we will present results for the electronic structure and conductance in the Kondo regime of recent STM and break junction experiments for stable radical molecules, which correspond to spin half molecular magnets. We will outline the methodological approach to evaluate the conductance of such systems from first principles, as implemented in the Smeagol electron transport code. The method combines the density functional theory (DFT) with Anderson impurity solvers within the continuum time quantum Monte Carlo (CTQMC) and numerical renormalization group (NRG) approaches.

  9. Weak interference in the high-signal regime.

    Science.gov (United States)

    Torres, Juan P; Puentes, Graciana; Hermosa, Nathaniel; Salazar-Serrano, Luis Jose

    2012-08-13

    Weak amplification is a signal enhancement technique which is used to measure tiny changes that otherwise cannot be determined because of technical limitations. It is based on: a) the existence of a weak interaction which couples a property of a system (the system) with a separate degree of freedom (the pointer), and b) the measurement of an anomalously large mean value of the pointer state (weak mean value), after appropriate pre-and post-selection of the state of the system. Unfortunately, the weak amplification process is generally accompanied by severe losses of the detected signal, which limits its applicability. However, we will show here that since weak amplification is essentially the result of an interference phenomena, it should be possible to use the degree of interference (weak interference) to get relevant information about the physical system under study in a more general scenario, where the signal is not severely depleted (high-signal regime). PMID:23038526

  10. Tokamak resistive magnetohydrodynamic ballooning instability in the negative shear regime

    Institute of Scientific and Technical Information of China (English)

    Shi Bing-Ren; Lin Jian-Long; Li Ji-Quan

    2007-01-01

    Improved confinement of tokamak plasma with central negative shear is checked against the resistive ballooning mode. In the negative shear regime, the plasma is always unstable for purely growing resistive ballooning mode. For a simplest tokamak equilibrium model, the s-α model, characteristics of this kind of instability are fully clarified by numerically solving the high n resistive magnetohydrodynamic ballooning eigen-equation. Dependences of the growth rate on the resistivity, the absolute shear value, the pressure gradient are scanned in detail. It is found that the growth rate is a monotonically increasing function of a while it is not sensitive to the changes of the shear s, the initial phase θ0 and the resistivity parameter εR.

  11. Three regimes of extrasolar planets inferred from host star metallicities

    CERN Document Server

    Buchhave, Lars A; Latham, David W; Sasselov, Dimitar; Cochran, William D; Endl, Michael; Isaacson, Howard; Juncher, Diana; Marcy, Geoffrey W

    2014-01-01

    Approximately half of the extrasolar planets (exoplanets) with radii less than four Earth radii are in orbits with short periods. Despite their sheer abundance, the compositions of such planets are largely unknown. The available evidence suggests that they range in composition from small, high-density rocky planets to low-density planets consisting of rocky cores surrounded by thick hydrogen and helium gas envelopes. Understanding the transition from the gaseous planets to Earth-like rocky worlds is important to estimate the number of potentially habitable planets in our Galaxy and provide constraints on planet formation theories. Here we report the abundances of heavy elements (that is, the metallicities) of more than 400 stars hosting 600 exoplanet candidates, and find that the exoplanets can be categorized into three populations defined by statistically distinct (~ 4.5{\\sigma}) metallicity regions. We interpret these regions as reflecting the formation regimes of terrestrial-like planets (radii less than 1...

  12. Transnational NGOs between Popular Uprising and Authoritarian Regime

    DEFF Research Database (Denmark)

    Farah, Abdulkadir Osman

    2013-01-01

    of disempowered youth, intense media-tech application and sustained international pressure as crucial to ousting authoritarian regimes in North Africa. Delineating the role of TNGOs complements such findings. TNGO activities and responses to the Egyptian uprising in 2011 and to the ensuing coup in 2013 reveal...... movements, organizations and communities engaged in de-territorialized socio‐cultural, political and economic activities. This paper focuses on the role of transnational NGOs (TNGOs) in recent developments in Egypt. The current scholarly debate on the so‐called “Arab spring” considers the mobilization...... positions of these organizations and might eventually encourage the return to authoritarianism. After introductory remarks on the background of the uprising, the paper proceeds to theoretical discussion of transnational engagement followed by recent historical and current empirical developments...

  13. Admittance measurements in the quantum Hall effect regime

    Energy Technology Data Exchange (ETDEWEB)

    Hernández, C., E-mail: carlos.hernandezr@unimilitar.edu.co [Departamento de Física, Universidad Militar Nueva Granada, Carrera 11 # 101-80, Bogotá D.C. (Colombia); Laboratorio de Magnetismo, Departamento de Física, Universidad de los Andes, A.A. 4976, Bogotá D.C. (Colombia); Consejo, C.; Chaubet, C. [Laboratoire Charles Coulomb L2C, Université Montpellier II, Pl. E. Bataillon, 34095 Montpellier Cedex 5 (France)

    2014-11-15

    In this work we present an admittance study of a two-dimensional electron gas (2DEG) in the quantum Hall effect (QHE) regime. We have studied several Hall bars in different contacts configurations in the frequency range 100 Hz–1 MHz. Our interpretation is based on the Landauer–Büttiker theory and takes into account both the capacitance and the topology of the coaxial cables which are connected to the sample holder. We show that we always observe losses through the capacitive impedance of the coaxial cables, except in the two contacts configuration in which the cable capacitance does not influence the admittance measurement of the sample. In this case, we measure the electrochemical capacitance of the 2DEG and show its dependence with the filling factor ν.

  14. Gravity-driven soap film dynamics in subcritical regimes

    Science.gov (United States)

    Auliel, M. I.; Castro, F.; Sosa, R.; Artana, G.

    2015-10-01

    We undertake the analysis of soap-film dynamics with the classical approach of asymptotic expansions. We focus our analysis in vertical soap film tunnels operating in subcritical regimes with elastic Mach numbers Me=O(10-1) . Considering the associated set of nondimensional numbers that characterize this flow, we show that the flow behaves as a two-dimensional (2D) divergence free flow with variable mass density. When the soap film dynamics agrees with that of a 2D and almost constant mass density flow, the regions where the second invariant of the velocity gradient is non-null correspond to regions where the rate of change of film thickness is non-negligible.

  15. Chiral effective field theory beyond the power-counting regime

    CERN Document Server

    Hall, Jonathan M M; Young, Ross D

    2011-01-01

    Novel techniques are presented, which identify the chiral power-counting regime (PCR), and realize the existence of an intrinsic energy scale embedded in lattice QCD results that extend outside the PCR. The nucleon mass is considered as a benchmark for illustrating this new approach. Using finite-range regularization, an optimal regularization scale can be extracted from lattice simulation results by analyzing the renormalization of the low energy coefficients. The optimal scale allows a description of lattice simulation results that extend beyond the PCR by quantifying and thus handling any scheme-dependence. Preliminary results for the nucleon magnetic moment are also examined, and a consistent optimal regularization scale is obtained. This indicates the existence of an intrinsic scale corresponding to the finite size of the source of the pion cloud.

  16. Power Counting Regime of Chiral Effective Field Theory and Beyond

    CERN Document Server

    Hall, J M M; Leinweber, D B

    2010-01-01

    Chiral effective field theory complements numerical simulations of quantum chromodynamics (QCD) on a space-time lattice. It provides a model-independent formalism for connecting lattice simulation results at finite volume and a variety of quark masses to the physical world. The asymptotic nature of the chiral expansion places the focus on the first few terms of the expansion. Thus, knowledge of the power-counting regime (PCR) of chiral effective field theory, where higher-order terms of the expansion may be regarded as negligible, is as important as knowledge of the expansion itself. Through the consideration of a variety of renormalization schemes and associated parameters, techniques to identify the PCR where results are independent of the renormalization scheme are established. The nucleon mass is considered as a benchmark for illustrating this general approach. Because the PCR is small, the numerical simulation results are also examined to search for the possible presence of an intrinsic scale which may b...

  17. Chiral extrapolation beyond the power-counting regime

    CERN Document Server

    Hall, J M M; Leinweber, D B; Liu, K F; Mathur, N; Young, R D; Zhang, J B

    2011-01-01

    Chiral effective field theory can provide valuable insight into the chiral physics of hadrons when used in conjunction with non-perturbative schemes such as lattice QCD. In this discourse, the attention is focused on extrapolating the mass of the rho meson to the physical pion mass in quenched QCD (QQCD). With the absence of a known experimental value, this serves to demonstrate the ability of the extrapolation scheme to make predictions without prior bias. By using extended effective field theory developed previously, an extrapolation is performed using quenched lattice QCD data that extends outside the chiral power-counting regime (PCR). The method involves an analysis of the renormalization flow curves of the low energy coefficients in a finite-range regularized effective field theory. The analysis identifies an optimal regulator, which is embedded in the lattice QCD data themselves. This optimal regulator is the regulator value at which the renormalization of the low energy coefficients is approximately i...

  18. Endemic time-spaces of Finland: Aquatic regimes

    Directory of Open Access Journals (Sweden)

    Tero Mustonen

    2014-08-01

    Full Text Available This article explores the endemic time-spaces of Finnish aquatic regimes. More precisely, it examines the socio-ecological relationships between Finns and lakes, rivers, and marshes-mires. First, the 'engine' of endemic time-space research, land use, and occupancy documentation, is explored in the Finnish context. Then two catchment areas, Kokemäenjoki in Western Finland and Vuoksi in Eastern Finland, provide cases which illustrate both past endemic time-spaces and surviving aspects of cultural readings of lakes and rivers. The ongoing winter seining in Lake Puruvesi in North Karelia emerges as an unbroken practice, with deep roots, that maintains the endemic time-spaces of a traditional Finnish relationship with a lake. As industrial uses of catchment areas, zoning, and environmental permitting exclude endemic readings inherent on the land and waterscapes, solutions are explored through mapping, along with its limitations, as a form bridging the gap between local realities and resource extraction.

  19. Transition from diffusive to localized regimes in surface corrugated waveguides

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Martin, A.; Saenz, J. J. [Universidad Autonoma de Madrid, Madrid (Spain); Nieto-Vesperinas, M. [Instituto de Ciencias de Materiales de Madrid, Madrid (Spain)

    2001-03-01

    Exact calculations of transmission and reflection coefficients in surface randomly corrugated waveguides are presented. The elastic scattering of diffuse light classical waves from a rough surface induces a diffusive transport along the waveguide axis. As the length of the corrugated part of the waveguide increases, a transition from the diffusive to the localized regime is observed. This involves an analogy with electron conduction in nano wires, and hence, a concept analogous to that of resistance can be introduced. An oscillatory behavior of different transport properties (elastic mean free path, localization length, enhanced backscattering), versus the wavelength is predicted. An analysis of the transmission coefficients (transmitted speckle) shows that as the length of the corrugated part of the waveguide increases there is a strong preference to forward coupling through the lowest mode. This marks a clear anisotropy in the forward propagation which is absent in the case of volume disorder. The statistics of reflection coefficients is analyzed, first using random matrix theory (Rm) to analytically deduce the probability densities in the localization regime, afterwards exact numerical calculations of the coupling to backward modes in surface corrugated waveguides will be put forward for comparison. We show that the reflected speckle distribution are independent of the transport regime, at variance with the regime transition found in the transmission case. Despite the strong anisotropy, the analysis of the probability distributions of both transmitted and reflected waves confirms the distributions predicted by Random Matrix Theory for volume disorder. [Spanish] Presentamos calculos exactos de los coeficientes de transmision y reflexion en guias de onda con desorden de superficie. La dispersion elastica de luz difusa o de otras ondas clasicas por una superficie rugosa induce un transporte difusivo a lo largo del eje de la guia. A medida que la longitud de la zona

  20. Principles Governing the Sustainability of Nuclear Security Regimes

    International Nuclear Information System (INIS)

    In order for nuclear security regimes, including nuclear security systems, to remain effective, they must be sustained over the long-term by States and by individual sites and installations. The objective of this paper is to define sustainability and provide a methodology for States, competent authorities, and operators on the content of sustainability programmes for nuclear security regimes. The U.S. Department of Energy (DOE) National Nuclear Security Administration (NNSA) Global Threat Reduction Initiative (GTRI) and the Office of International Material Protection and Cooperation (IMPC) have developed a methodology promoting the sustainability of improvements to nuclear security systems for prevention, detection and interdiction of the illicit movement of nuclear and other radioactive materials. These recommendations will help ensure that the capabilities established or strengthened through State-sponsored programs and/or donor State assistance remain effective and are supported and sustained over the long term by the host countries and by individual sites or installations. Physical protection and material control and accounting upgrades at facilities and radiation detection capacity building at borders and interior locations are critical elements of a national nuclear security regime. The efficacy of these prevention, detection and response measures is wholly dependent on sustaining their functionality. The sustainability of nuclear security facility upgrades and border security measures is ultimately the responsibility of the host country and each individual site or installation. This paper will provide the principles, guidance, performance measures, and best practices for establishing, assessing, and maintaining this functionality at national, regional and site levels. The methodology proposed in the paper addresses the varied infrastructures encountered among States. The premise is the establishment of a sustainability program which will ensure a nuclear