496 results on '"Berger, J. A."'
Search Results
2. Reduced density-matrix functional theory: Correlation and spectroscopy.
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Di Sabatino, S., Berger, J. A., Reining, L., and Romaniello, P.
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ELECTRON configuration , *DENSITY functional theory , *DENSITY matrices , *APPROXIMATION theory , *QUANTUM perturbations - Abstract
In this work, we explore the performance of approximations to electron correlation in reduced density-matrix functional theory (RDMFT) and of approximations to the observables calculated within this theory. Our analysis focuses on the calculation of total energies, occupation numbers, removal/addition energies, and spectral functions. We use the exactly solvable Hubbard dimer at 1/4 and 1/2 fillings as test systems. This allows us to analyze the underlying physics and to elucidate the origin of the observed trends. For comparison, we also report the results of the GW approximation, where the self-energy functional is approximated, but no further hypothesis is made concerning the approximations of the observables. In particular, we focus on the atomic limit, where the two sites of the dimer are pulled apart and electrons localize on either site with equal probability, unless a small perturbation is present: this is the regime of strong electron correlation. In this limit, using the Hubbard dimer at 1/2 filling with or without a spin-symmetry-broken ground state allows us to explore how degeneracies and spin-symmetry breaking are treated in RDMFT.We find that, within the used approximations, neither in RDMFT nor in GW, the signature of strong correlation is present, when looking at the removal/addition energies and spectral function from the spin-singlet ground state, whereas both give the exact result for the spin-symmetry broken case. Moreover, we show how the spectroscopic properties change from one spin structure to the other. [ABSTRACT FROM AUTHOR]
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- 2015
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3. A diagonalization‐free optimization algorithm for solving Kohn–Sham equations of closed‐shell molecules.
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Mrovec, Martin and Berger, J. A.
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MATHEMATICAL optimization , *GRASSMANN manifolds , *EQUATIONS , *CONSTRAINED optimization , *MOLECULES - Abstract
A local optimization algorithm for solving the Kohn–Sham equations is presented. It is based on a direct minimization of the energy functional under the equality constraints representing the Grassmann Manifold. The algorithm does not require an eigendecomposition, which may be advantageous in large‐scale computations. It is optimized to reduce the number of Kohn–Sham matrix evaluations to one per iteration to be competitive with standard self‐consistent field (SCF) approach accelerated by direct inversion of the iterative subspace (DIIS). Numerical experiments include a comparison of the algorithm with DIIS. A high reliability of the algorithm is observed in configurations where SCF iterations fail to converge or find a wrong solution corresponding to a stationary point different from the global minimum. The local optimization algorithm itself does not guarantee that the found minimum is global. However, a randomization of the initial approximation shows a convergence to the right minimum in the vast majority of cases. [ABSTRACT FROM AUTHOR]
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- 2021
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4. Autoantibodies in Covid‐19 – a model for viral induced autoimmunity.
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Berger, J. and Volc, S.
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COVID-19 , *ANTIPHOSPHOLIPID syndrome , *AUTOANTIBODIES , *AUTOIMMUNE diseases , *AUTOIMMUNITY , *SARS-CoV-2 , *AUTOIMMUNE hemolytic anemia - Abstract
Additionally, in most cases patients' basal autoantibody levels are not available, making it difficult to give a clear statement regarding the coherence of autoimmune phenomena and antibodies with a SARS-CoV-2 infection. The novel Coronavirus SARS-CoV-2 is suspected of acting as a trigger for autoimmune diseases and the production of autoantibodies. These aggregates activate transcription factor NF- B, which in turn stimulates the production of Type I IFN, interleukin-6 (IL-6) and further pro-inflammatory cytokines.15 Activation of plasmacytoid dendritic cells (pDC) follows Type I IFN-mediated activation of B cells which can lead to autoantibody production, e.g, anti-MDA5 antibodies. gl 1 TableOverview of reported autoantibodies in articles included in meta-analysis. [Extracted from the article]
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- 2021
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5. First contribution of the excavation and chronostratigraphic study of the Ruways 1 Neolithic shell midden (Oman) in terms of Neolithisation, palaeoeconomy, social‐environmental interactions and site formation processes.
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Berger, J. F., Guilbert‐Berger, R., Marrast, A., Munoz, O., Guy, H., Barra, A., López‐Sáez, J. A., Pérez‐Díaz, S., Mashkour, M., Debue, K., Lefèvre, C., Gosselin, M., Mougne, C., Bruniaux, G., Thorin, S., Nisbet, R., Oberlin, C., Mercier, N., Richard, M., and Depreux, B.
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SEDIMENTARY structures , *ARCHAEOLOGICAL archives , *ARCHAEOLOGICAL excavations , *ECONOMIC impact , *COASTAL archaeology - Abstract
The NeoArabia project tries to understand how environmental, social, economic and technological factors work in concert to influence settlement and abandonment along a latitudinal transect of 1200 km from UAE to southern Oman. This region was affected by wide north–south variations in the Indo‐Arabian monsoon, marine upwelling activity and eustatic variations in the Mid‐Holocene. On the local settlement scale, this transect is based on fine stratigraphic excavations and permits the reconstruction of the site formation processes and site catchment analysis. A large number of studies have been conducted on the Ruways‐1 site, focusing on a deep stratified sequence corresponding to three millennia of occupation. These studies include on‐site climate‐environmental signal analysis, local palaeogeography and environmental reconstruction, reservoir effect studies, typo‐technological studies, palaeoeconomic strategies, anthropological studies, sclerochronological studies and, finally, site formation processes, the understanding of which makes it possible to explain the potential and limits of the archaeological excavation. The first results confirm the richness of these archaeological archives for documenting the socio‐environmental dynamics, but also the richness of its complex sedimentary structure and the importance of conducting fine and multidisciplinary excavations to answer questions about the rhythms and functions of occupations and the causalities of socio‐environmental changes. [ABSTRACT FROM AUTHOR]
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- 2020
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6. Changing water use and adaptive strategies along rainfall gradients in Mediterranean lupins.
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Berger, J. D., Ludwig, C., Whisson, K., and Pfautsch, S.
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WATER use , *RAINFALL , *PLANT phenology , *BIOMASS production , *WATER supply , *WATER efficiency , *THROUGHFALL , *PLANT biomass - Abstract
There is growing interest in harnessing the genetic and adaptive diversity of crop wild relatives to improve drought resilience of elite cultivars. Rainfall gradients exert strong selection pressure on both natural and agricultural ecosystems. Understanding plant responses to these facilitates crop improvement.Wild and domesticated narrow‐leafed lupin (NLL) collected along Mediterranean terminal drought stress gradients was evaluated under contrasting reproductive phase water supply in controlled field, glasshouse and cabinet studies. Plant phenology, growth and productivity, water use and stress responses were measured over time.There is an integrated suite of adaptive changes along rainfall gradients in NLL. Low rainfall ecotypes flower earlier, accumulate lower seed numbers, biomass and leaf area, and have larger root:shoot ratios than high rainfall ecotypes. Water‐use is lower and stress onset slower in low compared to high rainfall ecotypes. Water‐use rates and ecotypic differences in stress response (Ψleaf decline, leaf loss) are lower in NLL than yellow lupin (YL). To mitigate the effects of profligate water use, high rainfall YL ecotypes maintain higher leaf water content over declining leaf water potential than low rainfall ecotypes. There is no evidence for such specific adaptation in NLL.The data suggests that appropriate phenology is the key adaptive trait to rainfall gradients in NLL because of the flow‐on effects on biomass production, fitness, transpiration and stress onset, and the lack of physiological adaptations as in YL. Accordingly, it is essential to match phenology with target environment in order to minimize risk and maximize yield potential. [ABSTRACT FROM AUTHOR]
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- 2020
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7. Experimental assessment of the similarity law for a one-dimensional coupled heat and water vapor diffusion in hemp concrete.
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Charaka, A., Berger, J., Benmahiddine, F., and Belarbi, R.
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WATER vapor , *MATHEMATICAL mappings , *COMPUTATIONAL fluid dynamics , *HEMP , *THERMAL stresses , *HYGROTHERMOELASTICITY - Abstract
• Similarity laws are verified in the framework of a one-dimensional heat and water vapor diffusion problem through an experimental campaign. • Two configurations of hemp concrete samples, equivalent in terms of similarity laws, are exposed to thermal and hydric stress. • Temperature and relative humidity at equivalent positions in both samples are measured and compared. • A detailed uncertainty investigation is proposed to discuss the reliability of the observed discrepancies. • The comparison of discrepancies and entire uncertainties show a good agreement between the reference and reduced configurations. Similarity law is a mathematical mapping that aims to set up equivalences between different configurations regarding the involved physical parameters, space dimensions and the duration of the configuration. These equivalences are defined by means of the dimensionless formulation of the physical model that describes a phenomenon. This concept is widely adopted in some scientific fields, notably in computational fluid dynamics. In heat and water vapor diffusion, similarities are applicable theoretically on configurations distinct in terms of material, space dimensions, duration or even imposed stress magnitude. It is worth noting that these are slow kinetic phenomena. In this regard, this study aims to verify similarities experimentally while using hemp concrete and reducing the duration of a reference experiment. Before performing measurements, two main limitations are fixed. First, by means of an experimental design, heat and moisture transfer are assumed one-dimensional. In addition, Dirichlet boundary conditions are considered at the surface that is exposed to ambient air. Mainly, temperature and relative humidity are measured at the quarter and middle of the material in order to compare the two similar configurations. Afterwards, an uncertainty study is carried out in order to discuss and justify the observed discrepancies. Following a deterministic approach, this investigation considers five sub-uncertainties which are related to : the calibration of used sensors, their positions, time of response, randomness of an experiment and the boundary condition modeling. Results show a good agreement between the reference and reduced configurations. Indeed, the discrepancies between both are entirely within the calculated confidence intervals. [ABSTRACT FROM AUTHOR]
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- 2023
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8. A physical model for the longitudinal polarizabilities of polymer chains.
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Berger, J. A., de Boeij, P. L., and van Leeuwen, R.
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POLYMERS , *OLIGOMERS , *POLARIZABILITY (Electricity) , *NUMERICAL analysis , *BOUNDARY value problems , *ELECTRIC fields - Abstract
The aim of this work is to provide a physical model to relate the polarizability per unit cell of oligomers to that of their corresponding infinite polymer chains. For this we propose an extrapolation method for the polarizability per unit cell of oligomers by fitting them to a physical model describing the dielectric properties of polymer chains. This physical model is based on the concept of a dielectric needle in which we assume a polymer chain to be well described by a cylindrically shaped nonconducting rod with a radius much smaller than its length. With this model we study in which way the polarizability per unit cell approaches the limit of the infinite chain. We show that within this model the macroscopic contribution of the induced electric field to the macroscopic electric field vanishes in the limit of an infinite polymer chain, i.e., there is no macroscopic screening. The macroscopic electric field becomes equal to the external electric field in this limit. We show that this identification leads to a relation between the polarizability per unit cell and the electric susceptibility of the infinite polymer chain. We test our dielectric needle model on the polarizability per unit cell of oligomers of the hydrogen chain and polyacetylene obtained earlier using time-dependent current-density-functional theory in the adiabatic local-density approximation and with the Vignale-Kohn functional. We also perform calculations using the same theory on truly infinite polymer chains by employing periodic boundary conditions. We show that by extrapolating the oligomer results according to our dielectric needle model we get good agreement with our results from calculations on the corresponding infinite polymer chains. [ABSTRACT FROM AUTHOR]
- Published
- 2005
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9. An experimental investigation of the nf Rydberg states of carbon disulfide.
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Berger, J.-P., Couris, S., and Gauyacq, D.
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RYDBERG states , *CARBON disulfide , *SPECTRUM analysis - Abstract
Studies the Rydberg states of carbon disulphide using resonance enhanced multiphoton ionization time-of-flight spectroscopy. Excitation spectrum of the compound; Convergence of the Rydberg to the spin-orbit components; Competition between dissociation and ionization processes.
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- 1997
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10. A multiphoton polarization study of the Rydberg states of OCS in the 70 500–74 500 cm-1 energy region.
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Berger, J. Ph., Baker, J., and Couris, S.
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POLARIZATION (Nuclear physics) , *RYDBERG states , *IONIZATION (Atomic physics) - Abstract
The polarization dependence of the (2+1) and (3+1) resonance enhanced multiphoton ionization of OCS have been investigated in the 70 500–74 500 cm-1 energy region. This region contains a complex system of bands arising from the excitation of the 4p Rydberg states. The symmetry of most of the observed bands have been unambiguously determined based on the intensity changes of the two and three photon resonant spectra using both linearly and circularly polarized light. These results generally confirm the assignments suggested in a previous study. New bands have also been observed and some new assignments are proposed. The vibrational frequencies ν1, ν2, and ν3 of the Rydberg states in that energy region are determined. © 1996 American Institute of Physics. [ABSTRACT FROM AUTHOR]
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- 1996
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11. A deep ocean acoustic noise floor, 1–800 Hz.
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Berger, J., Bidlot, J.-R., Dzieciuch, M. A., Farrell, W. E., Worcester, P. F., and Stephen, R. A.
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OCEAN tomography , *UNDERWATER acoustics , *NOISE , *OCEAN bottom , *TRANSMISSION of sound - Abstract
The ocean acoustic noise floor (observed when the overhead wind is low, ships are distant, and marine life silent) has been measured on an array extending up 987 m from 5048 m depth in the eastern North Pacific, in what is one of only a few recent measurements of the vertical noise distribution near the seafloor in the deep ocean. The floor is roughly independent of depth for 1–6 Hz, and the slope (∼
f −7) is consistent with Longuet-Higgins radiation from oppositely-directed surface waves. Above 6 Hz, the acoustic floor increases with frequency due to distant shipping before falling as ∼f −2 from 40 to 800 Hz. The noise floor just above the seafloor is only about 5 dB greater than during the 1975 CHURCH OPAL experiment (50–200 Hz), even though these measurements are not subject to the same bathymetric blockage. The floor increases up the array by roughly 15 dB for 40–500 Hz. Immediately above the seafloor, the acoustic energy is concentrated in a narrow, horizontal beam that narrows asf −1 and has a beam width at 75 Hz that is less than the array resolution. The power in the beam falls more steeply with frequency than the omnidirectional spectrum. [ABSTRACT FROM AUTHOR]- Published
- 2018
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12. Intra-oceanic arc growth driven by magmatic and tectonic processes recorded in the Neoproterozoic Bougmane arc complex (Anti-Atlas, Morocco).
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Triantafyllou, A., Berger, J., Baele, J-m., Bruguier, O., Diot, H., Ennih, N., Monnier, C., Plissart, G., Vandycke, S., and Watlet, A.
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HORNBLENDITE , *GEOCHEMISTRY , *ZIRCON , *FELSIC rocks , *PLAGIOCLASE - Published
- 2018
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13. Daniel Gogny.
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Berger, J., Blaizot, J., Bouche, D., Chaix, P., Delaroche, J., Dupuis, M., Girod, M., Gogny, J., Grammaticos, B., Iracane, D., Lachkar, J., Mariotte, F., Pillet, N., and Van Giai, N.
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PLASMA physics , *ELECTROMAGNETISM , *ATOMIC structure , *NUCLEAR physics , *PLASMA gases - Abstract
In this article, the scientific life of D. Gogny is recounted by several collaborators. His strong involvement in researches related to various fields of physics (such as nuclear, atomic and plasma physics as well as electromagnetism) appears clearly, as well as the progresses made in the understanding of fundamental physics. [ABSTRACT FROM AUTHOR]
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- 2017
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14. A0946 - Erector spinae plane blocks for analgesia after percutaneous nephrolithotomy: A pathway to reduce opiates.
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Berger, J., Abdou, W., Roberts, J., Ryan, J., Attaluri, S., Sur, R., Finneran Iv, J., and Bechis, S.
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ERECTOR spinae muscles , *PERCUTANEOUS nephrolithotomy , *NARCOTICS , *ANALGESIA - Published
- 2023
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15. Determining best practices in reconnoitering sites for habitability potential on Mars using a semi-autonomous rover: A GeoHeuristic Operational Strategies Test.
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Yingst, R.A., Berger, J., Cohen, B.A., Hynek, B., and Schmidt, M.E.
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ROVING vehicles (Astronautics) , *SPACE vehicles , *SPACE flight , *MARTIAN geology , *DECISION making in science - Abstract
We tested science operations strategies developed for use in remote mobile spacecraft missions, to determine whether reconnoitering a site of potential habitability prior to in-depth study (a walkabout-first strategy) can be a more efficient use of time and resources than the linear approach commonly used by planetary rover missions. Two field teams studied a sedimentary sequence in Utah to assess habitability potential. At each site one team commanded a human “rover" to execute observations and conducted data analysis and made follow-on decisions based solely on those observations. Another team followed the same traverse using traditional terrestrial field methods, and the results of the two teams were compared. Test results indicate that for a mission with goals similar to our field case, the walkabout-first strategy may save time and other mission resources, while improving science return. The approach enabled more informed choices and higher team confidence in choosing where to spend time and other consumable resources. The walkabout strategy may prove most efficient when many close sites must be triaged to a smaller subset for detailed study or sampling. This situation would arise when mission goals include finding, identifying, characterizing or sampling a specific material, feature or type of environment within a certain area. [ABSTRACT FROM AUTHOR]
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- 2017
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16. P08 Radiosensitivity and impaired DNA double-strand break repair in HPV-positive OPSCC: The role of smoking and the ATM kinase as observed in ex vivo and in vitro studies.
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Zech, H., Berger, J., Petersen, C., Betz, C., Rothkamm, K., Kriegs, M., Köcher, S., and Rieckmann, T.
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DOUBLE-strand DNA breaks , *RADIATION tolerance , *IN vitro studies , *AUTOMATED teller machines - Published
- 2022
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17. Wind Sea behind a Cold Front and Deep Ocean Acoustics.
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Farrell, W. E., Berger, J., Bidlot, J.-R., Dzieciuch, M., Munk, W., Stephen, R. A., and Worcester, P. F.
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FRONTS (Meteorology) , *OCEAN bottom , *ACOUSTIC radiation , *OCEAN-atmosphere interaction , *OVERLAP integral - Abstract
A rapid and broadband (1 h, 1 < f < 400 Hz) increase in pressure and vertical velocity on the deep ocean floor was observed on seven instruments comprising a 20-km array in the northeastern subtropical Pacific. The authors associate the jump with the passage of a cold front and focus on the 4- and 400-Hz spectra. At every station, the time of the jump is consistent with the front coming from the northwest. The apparent rate of progress, 10-20 km h−1 (2.8-5.6 m s−1), agrees with meteorological observations. The acoustic radiation below the front is modeled as arising from a moving half-plane of uncorrelated acoustic dipoles. The half-plane is preceded by a 10-km transition zone, over which the radiator strength increases linearly from zero. With this model, the time derivative of the jump at a station yields a second and independent estimate of the front's speed, 8.5 km h−1 (2.4 m s−1). For the 4-Hz spectra, the source physics is taken to be Longuet-Higgins radiation. Its strength depends on the quantity , where F ζ is the wave amplitude power spectrum and I the overlap integral. Thus, the 1-h time constant observed in the bottom data implies a similar time constant for the growth of the wave field quantity behind the front. The spectra at 400 Hz have a similar time constant, but the jump occurs 25 min later. The implications of this difference for the source physics are uncertain. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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18. Identification of Volatile Organic Compounds of Solid Waste by Pyrolysis GC/MS for Environmental Impact and Green Manufacturing.
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Maleknia, S. D., Berger, J., and Odermatt, J.
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SOLID waste , *VOLATILE organic compounds , *WASTE recycling - Abstract
Global levels of urban municipal solid waste (MSW) are expected to near 4 billion tonnes per year by 2025. While recycling methodologies have advanced and despite global environmental concerns, incineration and burning are still practiced as a quick solution to waste management. Other recent advances have developed new methodologies to utilise end of life waste products as feedstock of industrial processes. This study has applied temperature dependent pyrolysis GC/ MS from thermal desorption at 250 °C to degradation temperature of 500 °C, to identify volatile organic compounds (VOCs) released from various types of urban municipal solid waste materials. Focus was set on their potential use in green manufacturing processes, and to better estimate the range of pollutants introduced into the atmosphere as greenhouse gases (GHGs), in relation to waste management during incineration/burning. [ABSTRACT FROM AUTHOR]
- Published
- 2016
19. An ocean bottom seismic observatory with near real‐time telemetry.
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Berger, J., Laske, G., Babcock, J., and Orcutt, J.
- Abstract
Abstract: We describe a new technology that can provide near real‐time telemetry of sensor data from the ocean bottom without a moored buoy or a cable to shore. The breakthrough technology that makes this system possible is an autonomous surface vehicle called a Wave Glider developed by Liquid Robotics, Inc. of Sunnyvale, CA, which harvests wave and solar energy for motive and electrical power. We present results from several deployments of a prototype system that demonstrate the feasibility of this concept. We also demonstrated that a wave glider could tow a suitably designed ocean bottom package with acceptable loss of speed. With further development such a system could be deployed autonomously and provide real‐time telemetry of data from seafloor sensors. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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20. Fully Parameter-Free Calculation of Optical Spectra for Insulators, Semiconductors, and Metals from a Simple Polarization Functional.
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Berger, J. A.
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OPTICAL spectra , *SEMICONDUCTORS , *POLARIZATION (Electricity) , *DENSITY functional theory , *ABSORPTION spectra , *ELECTRIC insulators & insulation - Abstract
We present a fully parameter-free density-functional approach for the accurate description of optical absorption spectra of insulators, semiconductors, and metals. We show that this can be achieved within time-dependent current-density-functional theory using a simple dynamical polarization functional. We derive this functional from physical principles that govern optical spectra. Our method is truly predictive because not a single parameter is used. In particular, we do not use an ad hoc material-dependent broadening parameter to compare theory to experiment as is usually done. Our approach is numerically efficient; the cost equals that of a calculation within the random-phase approximation. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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21. Molecular phylogeny indicates polyphyly in Raphanus L. (Brassicaceae).
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Ziffer-Berger, J., Hanin, N., Fogel, T., Mummenhoff, K., and Barazani, O.
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RADISHES , *PLANT phylogeny , *MOLECULAR phylogeny , *BRASSICA , *PLANT genes - Abstract
We evaluated the systematic relationship of the two sections of Raphanus (Brassicaceae) on the basis of morphological and ITS data. We obtained strong support that Raphanus is a polyphyletic group embedded in the Oleracea lineage of the tribe Brassiceae. Section Raphanis, which includes Raphanus raphanistrum, R. pugioniformis and R. sativus, is a strongly supported monophyletic lineage. Section Hesperidopsis is embedded in a different lineage together with Brassica deflexa and B. aucheri. We propose to reinstate the genus Quidproquo in place of Raphanus sect. Hesperidopsis as reflected by both morphological data and ITS phylogeny. [ABSTRACT FROM PUBLISHER]
- Published
- 2015
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22. INTERFEROMETRIC INSTRUMENTATION.
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Berger, J.-P.
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INTERFEROMETRY , *OPTICAL interferometers , *VERY large telescopes , *ASTRONOMICAL instruments , *ASTROPHYSICS - Abstract
We present in this chapter a description of optical interferometry combining instruments. For that purpose we describe the role of different key functions and give examples of the choice made in current and future instruments in particular at VLTI. [ABSTRACT FROM AUTHOR]
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- 2015
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23. Contrasting adaptive strategies to terminal drought-stress gradients in Mediterranean legumes: phenology, productivity, and water relations in wild and domesticated Lupinus luteus L.
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Berger, J. D. and Ludwig, C.
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LEGUME genetics , *EFFECT of drought on plants , *PLANT phenology , *PLANT-water relationships , *LUPINUS luteus - Abstract
Rainfall gradients select for contrasting, integrated, adaptive strategies in the Mediterranean legume, Lupinus luteus, where phenology, productivity, fecundity, and water-use are matched to seasonal rainfall. Profligate high-rainfall ecotypes have developed drought tolerance that is redundant in drought-avoiding low-rainfall ecotypes.Our understanding of within-species annual plant adaptation to rainfall gradients is fragmented. Broad-scale ecological applications of Grime’s C-S-R triangle are often superficial, while detailed drought physiology tends to be narrow, focusing on elite cultivars. The former lack the detail to explain how plants respond, while the latter provide little context to investigate trade-offs among traits, to explain where/why these might be adaptive. Ecophysiology, combining the breadth of the former with the detail of the latter, can resolve this disconnect and is applied here to describe adaptive strategies in the Mediterranean legume Lupinus luteus. Wild and domesticated material from low- and high-rainfall environments was evaluated under contrasting terminal drought. These opposing environments have selected for contrasting, integrated, adaptive strategies. Long-season, high-rainfall habitats select for competitive (C) traits: delayed phenology, high above- and below-ground biomass, productivity, and fecundity, leading to high water-use and early stress onset. Terminal drought-prone environments select for the opposite: ruderal (R) traits that facilitate drought escape/avoidance but limit reproductive potential. Surprisingly, high-rainfall ecotypes generate lower critical leaf water potentials under water deficit, maintaining higher relative water content than the latter. Given that L. luteus evolved in sandy, low-water-holding capacity soils, this represents a bet-hedging response to intermittent self-imposed water-deficits associated with a strongly C-selected adaptive strategy that is therefore redundant in R-selected low-rainfall ecotypes. Domesticated L. luteus is even more R-selected, reflecting ongoing selection for early maturity. Introgression of appropriate C-selected adaptive traits from wild germplasm may widen the crop production range. [ABSTRACT FROM PUBLISHER]
- Published
- 2014
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24. Factors affecting nasal intermittent positive pressure ventilation failure and impact on bronchopulmonary dysplasia in neonates.
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Mehta, P, Berger, J, Bucholz, E, and Bhandari, V
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Background:Nasal intermittent positive pressure ventilation (NIPPV) is becoming more important as a mode of ventilation in premature neonates predisposed to development of bronchopulmonary dysplasia (BPD). To the best of our knowledge, there have been no detailed studies characterizing neonates who fail NIPPV.Objective:To determine the differences between neonates who are successfully extubated to NIPPV and those who require re-intubation from NIPPV, and the impact of timing of NIPPV failure on BPD rates.Study Design:This was a retrospective cohort study in which we included infants with gestational age (GA) ⩽28 weeks and birth weight ⩽1000 g. χ2-test, analysis of variance and multivariate logistic regression models were used.Results:Two hundred and forty infants were studied; 180 failed NIPPV and of those, 33 (18%), 39 (22%) and 108 (60%) failed NIPPV within 0 to 6 h, ⩾6 to 24 h and ⩾24 h, respectively. Female sex and increased weight were protective against NIPPV failure (adjusted odds ratio (95% confidence interval): 0.28 (0.14 to 0.58), 0.04 (0.01 to 0.22)). Increased GA at extubation and female sex were both associated with increased time to failure (P=0.008, <0.001, respectively). Apnea was more likely the cause for failure ⩾24 h (P=0.015), whereas increased work of breathing/fraction of inspired oxygen requirements were more significant when NIPPV failure occurred earlier (P=0.001). Neonates who failed NIPPV within 24 h did not have any association with likelihood of developing BPD or severity of BPD, after adjusting for confounding variables.Conclusion:Significant differences in neonatal characteristics may help identify which neonates are more likely to fail NIPPV, and their timing of failure. [ABSTRACT FROM AUTHOR]
- Published
- 2014
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25. Factors affecting nasal intermittent positive pressure ventilation failure and impact on bronchopulmonary dysplasia in neonates.
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Mehta, P, Berger, J, Bucholz, E, and Bhandari, V
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BRONCHOPULMONARY dysplasia , *ACADEMIC medical centers , *ANALYSIS of variance , *BODY weight , *CHI-squared test , *CONFIDENCE intervals , *FISHER exact test , *GESTATIONAL age , *INTERMITTENT positive pressure breathing , *MEDICAL records , *MULTIVARIATE analysis , *RISK assessment , *SEX distribution , *LOGISTIC regression analysis , *RETROSPECTIVE studies , *SEVERITY of illness index , *MEDICAL equipment reliability , *DATA analysis software , *DESCRIPTIVE statistics , *ODDS ratio , *THERAPEUTICS - Abstract
Background:Nasal intermittent positive pressure ventilation (NIPPV) is becoming more important as a mode of ventilation in premature neonates predisposed to development of bronchopulmonary dysplasia (BPD). To the best of our knowledge, there have been no detailed studies characterizing neonates who fail NIPPV.Objective:To determine the differences between neonates who are successfully extubated to NIPPV and those who require re-intubation from NIPPV, and the impact of timing of NIPPV failure on BPD rates.Study Design:This was a retrospective cohort study in which we included infants with gestational age (GA) ⩽28 weeks and birth weight ⩽1000 g. χ2-test, analysis of variance and multivariate logistic regression models were used.Results:Two hundred and forty infants were studied; 180 failed NIPPV and of those, 33 (18%), 39 (22%) and 108 (60%) failed NIPPV within 0 to 6 h, ⩾6 to 24 h and ⩾24 h, respectively. Female sex and increased weight were protective against NIPPV failure (adjusted odds ratio (95% confidence interval): 0.28 (0.14 to 0.58), 0.04 (0.01 to 0.22)). Increased GA at extubation and female sex were both associated with increased time to failure (P=0.008, <0.001, respectively). Apnea was more likely the cause for failure ⩾24 h (P=0.015), whereas increased work of breathing/fraction of inspired oxygen requirements were more significant when NIPPV failure occurred earlier (P=0.001). Neonates who failed NIPPV within 24 h did not have any association with likelihood of developing BPD or severity of BPD, after adjusting for confounding variables.Conclusion:Significant differences in neonatal characteristics may help identify which neonates are more likely to fail NIPPV, and their timing of failure. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
26. Concentration-Dependent Chemical Expansion in Lithium-Ion Battery Cathode Particles.
- Author
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Malavé, Veruska, Berger, J. R., and Martin, P. A.
- Subjects
- *
LITHIUM-ion batteries , *ELECTROCHEMICAL electrodes , *ELECTRIC charge , *STRAINS & stresses (Mechanics) , *ELECTROCHEMISTRY - Abstract
In this work, the effect of the concentration-dependent chemical-expansion coefficient, ß, on the chemo-elastic field in lithium-ion cathode particles is examined. To accomplish this, an isotropic linear-elastic model is developed for a single idealistic particle subjected to potentiostatic-discharge and charge conditions. It is shown that ß can be a key parameter in demarcating the chemo-stress-strain state of the cathode material undergoing nonlinear volumetric strains. As an example, such strains develop in the hexagonal-to-monoclinic-phase region of LixCoO2 (0.37≤x≤0.55) and, subsequently, the corresponding ß is a linear function of concentration. Previous studies have assumed a constant value for ß. Findings suggest that the composition-generated chemo-elastic field that is based on a linear-ß dramatically affects both the interdiffusion and the mechanical behavior of the LixCoO2 cathode particle. Because the chemo-elastic phenomena emanate in a reciprocal fashion, the resulting linear ß-based hydrostatic-stress gradients significantly aid the diffusion of lithium. Thus, diffusion is accelerated in either electrochemical process that the cathode material undergoes. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
27. Low energy fission: dynamics and scission configurations.
- Author
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Goutte, H., Berger, J.-F., Gogny, D., and Younes, W.
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- *
NUCLEAR fission , *SCISSION (Chemistry) , *NUCLEAR reactions , *NUCLEAR energy , *NUCLEAR physics - Abstract
In the first part of this paper we recall a recent study concerning low energy fission dynamics. Propagation is made by use of the Time Dependent Generator Coordinate Method, where the basis states are taken from self-consistent Hartree-Fock-Bogoliubov calculations with the Gogny force. Theoretical fragment mass distributions are presented and compared with the evaluation made by Wahl. In the second part of this paper, new results concerning scission configurations are shown. Deviations of the fission fragment proton numbers from the Unchanged Charge Distribution prescription and fission fragment deformations are discussed. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]
- Published
- 2005
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28. Fission: Potential Energy Surfaces and Dynamics.
- Author
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Goutte, H., Berger, J. F., and Gogny, D.
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- *
POTENTIAL energy surfaces , *QUANTUM chemistry , *QUANTUM theory , *HARTREE-Fock approximation , *ENERGY-band theory of solids , *NUCLEAR reactions , *NUCLEAR physics - Abstract
Recent microscopic studies devoted to fission are presented. First, potential energy surface properties are extracted using the Hartree-Fock-Bogoliubov theory with constraints. Then, dynamical properties of the fission process are studied by use of the time-dependent Generator Coordinate Method based on self-consistent intrinsic nuclear wave functions calculated with the Gogny force. The influence of fission dynamics on fragment mass distributions is discussed. © 2005 American Institute of Physics [ABSTRACT FROM AUTHOR]
- Published
- 2005
- Full Text
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29. Critical Review of Quark Gluon Plasma Signatures.
- Author
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Stöcker, H., Berger, J., Eichmann, U., Salur, S., Scherer, S., and Zschiesche, D.
- Subjects
- *
QUARK-gluon plasma , *HEAVY ion collisions , *MESONS - Abstract
We discuss the uniqueness of often proposed experimental signatures for quark matter formation in relativistic heavy ion collisions, using insight gained from non-equilibrium models (three-fluid hydrodynamics and the hadronic transport model UrQMD). It is demonstrated that these two models — although they do treat the most interesting early phase of the collisions quite differently (thermalizing QGP vs. coherent color fields with virtual particles) both yield a reasonable agreement with a large variety of the available heavy ion data. Hadron/hyperon yields, including J/Ψ meson production/suppression, strange matter formation, dileptons, and directed flow (bounce-off and squeeze-out) are investigated. Observations of interesting phenomena in dense matter are reported. However, we emphasize the need for systematic furore measurements to search for simultaneous irregularities in the excitation functions of several observables in order to come close to pinning the properties of hot, dense QCD matter from data. [ABSTRACT FROM AUTHOR]
- Published
- 2002
30. Pathophysiology of X-linked adrenoleukodystrophy.
- Author
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Berger, J., Forss-Petter, S., and Eichler, F.S.
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- *
PATHOLOGICAL physiology , *ADRENOLEUKODYSTROPHY , *MOLECULAR biology , *PHENOTYPES , *CYTOSOL , *NEUROPATHY - Abstract
Abstract: Currently the molecular basis for the clinical heterogeneity of X-linked adrenoleukodystrophy (X-ALD) is poorly understood. The genetic bases for all different phenotypic variants of X-ALD are mutations in the gene encoding the peroxisomal ATP-binding cassette (ABC) transporter, ABCD1 (formerly adrenoleukodystrophy protein, ALDP). ABCD1 transports CoA-activated very long-chain fatty acids from the cytosol into the peroxisome for degradation. The phenotypic variability is remarkable ranging from cerebral inflammatory demyelination of childhood onset, leading to death within a few years, to adults remaining pre-symptomatic through more than five decades. There is no general genotype–phenotype correlation in X-ALD. The default manifestation of mutations in ABCD1 is adrenomyeloneuropathy, a slowly progressive dying-back axonopathy affecting both ascending and descending spinal cord tracts as well as in some cases, a peripheral neuropathy. In about 60% of male X-ALD patients, either in childhood (35–40%) or in adulthood (20%), an initial, clinically silent, myelin destabilization results in conversion to a devastating, rapidly progressive form of cerebral inflammatory demyelination. Here, ABCD1 remains a susceptibility gene, necessary but not sufficient for inflammatory demyelination to occur. Although the accumulation of very long-chain fatty acids appears to be essential for the pathomechanism of all phenotypes, the molecular mechanisms underlying these phenotypes are fundamentally different. Cell autonomous processes such as oxidative stress and energy shortage in axons as well as non-cell autonomous processes involving axon–glial interactions seem pertinent to the dying-back axonopathy. Various dynamic mechanisms may underlie the initiation of inflammation, the altered immune reactivity, the propagation of inflammation, as well as the mechanisms leading to the arrest of inflammation after hematopoietic stem cell transplantation. An improved understanding of the molecular mechanisms involved in these events is required for the development of urgently needed therapeutics. [Copyright &y& Elsevier]
- Published
- 2014
- Full Text
- View/download PDF
31. Mapping of Hückel zigzag carbon nanotubes onto independent polyene chains: Application to periodic nanotubes.
- Author
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François, Grégoire, Angeli, Celestino, Bendazzoli, Gian Luigi, Brumas, Véronique, Evangelisti, Stefano, and Berger, J. Arjan
- Subjects
- *
CARBON nanotubes , *NANOTUBES , *HEXAGONS , *TORUS , *TOPOLOGY - Abstract
The electric polarizability and the spread of the total position tensors are used to characterize the metallic vs insulator nature of large (finite) systems. Finite clusters are usually treated within the open boundary condition formalism. This introduces border effects, which prevent a fast convergence to the thermodynamic limit and can be eliminated within the formalism of periodic boundary conditions. Recently, we introduced an original approach to periodic boundary conditions, named Clifford boundary conditions. It considers a finite fragment extracted from a periodic system and the modification of its topology into that of a Clifford torus. The quantity representing the position is modified in order to fulfill the system periodicity. In this work, we apply the formalism of Clifford boundary conditions to the case of carbon nanotubes, whose treatment results in a particularly simple zigzag geometry. Indeed, we demonstrate that at the Hückel level, these nanotubes, either finite or periodic, are formally equivalent to a collection of non-interacting dimerized linear chains, thus simplifying their treatment. This equivalence is used to describe some nanotube properties as the sum of the contributions of the independent chains and to identify the origin of peculiar behaviors (such as conductivity). Indeed, if the number of hexagons along the circumference is a multiple of three, a metallic behavior is found, namely a divergence of both the (per electron) polarizability and total position spread of at least one linear chain. These results are in agreement with those in the literature from tight-binding calculations. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
32. Vestibular testing in children – The suppression head impulse (SHIMP) test.
- Author
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Nguyen, J., Berger, J., Curthoys, I., Held, V., Zaubitzer, L., Hülse, R., Rotter, N., and Schell, A.
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- *
VERTIGO , *BALANCE disorders , *VESTIBULAR apparatus , *MEDICAL personnel , *ADULTS , *VERBAL ability , *SYMPTOMS - Abstract
The incidence of vestibular disorders and vertigo during childhood is increasing and pediatric clinicians have become more sensitive to children's balance disorders; thus, there is a need for appropriate detection test procedures for peripheral vestibular hypofunction. In order to ensure a reliable diagnosis and minimize misdiagnosis, a standardized clinical procedure via careful history and clinical examination is recommended. However, children, especially, are often unable to verbalize "vertigo" in a concrete manner, which often necessitates a consultation with a pediatrician holding nonspecific symptoms. The so-called suppression of the head impulse test (SHIMPs) represents a modification of the video head impulse test (HIMP) and is used for a more sensitive assessment of residual vestibular functions. In adults, SHIMPs are already an established diagnostic method. Nevertheless, to date, nothing is known about the applicability and standard values in childhood. In this monocentric, prospective study, we investigated whether SHIMPs enable a sensitive functional analysis of the vestibular system in healthy children of different ages. For this purpose, SHIMPs were performed in 40 children aged 3–18 years. In this study, we demonstrated that SHIMPs can be easily performed in children (3–18 years). It is vital that the test be appropriately explained for children to ensure sufficient test tolerance and compliance. SHIMPs are a helpful supplement to clinically established vestibular tests such as the HIMP in pediatric vestibular balance disorder diagnostics and can be integrated into the clinical routine, especially in children who have minimal verbal abilities or understanding of the instructions for HIMP. Similar to the HIMP, SHIMPs are characterized by a short test duration and a high tolerance. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
33. Boundary element analysis for effective stiffness tensors: effect of fabric tensor determination method.
- Author
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Elmabrouk, B. and Berger, J.
- Subjects
- *
BOUNDARY element methods , *STIFFNESS (Mechanics) , *TENSOR algebra , *ANISOTROPY , *ORTHOTROPY (Mechanics) , *ELASTICITY , *POROUS materials , *MICROSTRUCTURE - Abstract
Second-rank fabric tensors have been extensively used to describe structural anisotropy and to predict orthotropic elastic constants. However, there are many different definitions of, and approaches to, determining the fabric tensor. Most commonly used is a fabric tensor based on mean intercept length measurements, but star volume distribution and star length distribution are commonly used, particularly in studies of trabecular bone. Here, we investigate the effect of the fabric tensor definition on elastic constant predictions using both synthetic, idealized microstructures as well as a micrograph of a porous ceramic. We use an efficient implantation of a symmetric Galerkin boundary element method to model the mechanical response of the various microstructures, and also use a boundary element approach to calculate the necessary volume averages of stress and strain to obtain the effective properties of the media. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
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34. Apparent stiffness tensors for porous solids using symmetric Galerkin boundary elements.
- Author
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Elmabrouk, B., Berger, J., Phan, A., and Gray, L.
- Subjects
- *
BOUNDARY element methods , *STIFFNESS (Mechanics) , *POROUS materials , *GALERKIN methods , *STRAINS & stresses (Mechanics) , *SOLIDS , *EIGENVALUES - Abstract
Representative volume elements (RVEs) from porous or cellular solids can often be too large for numerical or experimental determination of effective elastic constants. Volume elements which are smaller than the RVE can be useful in extracting apparent elastic stiffness tensors which provide bounds on the homogenized elastic stiffness tensor. Here, we make efficient use of boundary element analysis to compute the volume averages of stress and strain needed for such an analysis. For boundary conditions which satisfy the Hill criterion, we demonstrate the extraction of apparent elastic stiffness tensors using a symmetric Galerkin boundary element method. We apply the analysis method to two examples of a porous ceramic. Finally, we extract the eigenvalues of the fabric tensor for the example problem and provide predictions on the apparent elastic stiffnesses as a function of solid volume fraction. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
35. Domestication bottlenecks limit genetic diversity and constrain adaptation in narrow-leafed lupin ( Lupinus angustifolius L.).
- Author
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Berger, J., Buirchell, B., Luckett, D., and Nelson, M.
- Subjects
- *
PLANT diversity , *LUPINUS angustifolius , *PLANT breeding , *PLANT population genetics , *VERNALIZATION , *PLANT adaptation - Abstract
In contrast to most widespread broad-acre crops, the narrow-leafed lupin ( Lupinus angustifolius L.) was domesticated very recently, in breeding programmes isolated in both space and time. Whereas domestication was initiated in Central Europe in the early twentieth century, the crop was subsequently industrialized in Australia, which now dominates world production. To investigate the ramifications of these bottlenecks, the genetic diversity of wild ( n = 1,248) and domesticated populations ( n = 95) was characterized using diversity arrays technology, and adaptation studied using G × E trials ( n = 31) comprising all Australian cultivars released from 1967 to 2004 ( n = 23). Principal coordinates analysis demonstrates extremely limited genetic diversity in European and Australian breeding material compared to wild stocks. AMMI analysis indicates that G × E interaction is a minor, albeit significant effect, dominated by strong responses to local, Western Australian (WA) optima. Over time Australian cultivars have become increasingly responsive to warm, intermediate rainfall environments in the northern WA grainbelt, but much less so to cool vegetative phase eastern environments, which have considerably more yield potential. G × E interaction is well explained by phenology, and its interaction with seasonal climate, as a result of varying vernalization responses. Yield differences are minimized when vegetative phase temperatures fully satisfy the vernalization requirement (typical of eastern Australia), and maximized when they do not (typical of WA). In breeding for WA optima, the vernalization response has been eliminated and there has been strong selection for terminal drought avoidance through early phenology, which limits yield potential in longer season eastern environments. Conversely, vernalization-responsive cultivars are more yield-responsive in the east, where low temperatures moderately extend the vegetative phase. The confounding of phenology and vernalization response limits adaptation in narrow-leafed lupin, isolates breeding programmes, and should be eliminated by widening the flowering time range in a vernalization-unresponsive background. Concomitantly, breeding strategies that will widen the genetic base of the breeding pool in an ongoing manner should be initiated. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
36. Efficient GW calculations for SnO2, ZnO, and rubrene: The effective-energy technique.
- Author
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Berger, J. A., Reining, Lucia, and Sottile, Francesco
- Subjects
- *
STANNIC oxide , *ZINC oxide , *ELECTRONIC excitation , *NUMERICAL analysis , *BAND gaps , *MOLECULAR crystals , *SPECTRUM analysis , *POLYCYCLIC compounds - Abstract
In a recent Rapid Communication (J. A. Berger, L. Reining, and F Sottile, Phys. Rev. B 82,041103(R) (2010)], we presented the effective-energy technique to evaluate, in an accurate and numerically efficient manner, electronic excitations by reformulating spectral sum-over-states expressions such that only occupied states appear. In our approach all the empty states are accounted for by a single effective energy that can be obtained from first principles. In this work we provide further details of the effective-energy technique, in particular, when combined with the GW method, in which a huge summation over empty states appears in the calculation of both the screened Coulomb interaction and the self-energy. We also give further evidence of the numerical accuracy ol the effective-energy technique by applying it to the technological important materials SnO2 and ZnO. Finally, we use this technique to predict the band gap of bulk rubrene, an organic molecular crystal with a 140-atom unit cell. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
37. Chickpea evolution has selected for contrasting phenological mechanisms among different habitats.
- Author
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Berger, J. D., Milroy, S. P., Turner, N. C., Siddique, K. H. M., Imtiaz, M., and Malhotra, R.
- Subjects
- *
CHICKPEA , *BIOLOGICAL evolution , *HABITATS , *CROP adaptation , *PHENOLOGY , *CLIMATE change , *META-analysis , *PLANT germplasm - Abstract
guably the most important adaptive criterion in annual crops is appropriate phenology that minimizes exposure to climatic stresses and maximizes productivity in target environments. To date this has been achieved empirically by selecting among diverse genotypes in target locations. This approach is likely to become inadequate with pending climate change because selection is imposed on the outcome (flowering time) rather than the underlying mechanism (i.e. responses to daylength, ambient or vernalizing temperatures). In contrast to the cereals, in legumes the interaction between phenological mechanisms and environmental selection pressure is largely unknown. This paper addresses this shortcoming through photothermal modelling of chickpea germplasm from the world's key production areas using a meta-analysis of multi-environment trials located from 49° N to 35° S. Germplasm origin had significant effects on temperature and daylength responsiveness, the former strongly correlated to vegetative phase temperatures at the collection or development site ( r = 0.8). Accordingly, temperature responses increase from winter- to spring-sown Mediterranean and Australian material, and then to north, central & southern India. Germplasm origin also affects the relationship between photoperiod and temperature response. In Eastern Mediterranean material a strong negative relationship ( r = −0.77) enables temperature insensitive genotypes to compensate through a strong photoperiod response. Clearly, chickpea evolution has selected for different phenological mechanisms across the habitat range. Given that under the anticipated global warming temperature sensitive cultivars will flower relatively earlier than those responding largely to photoperiod, it is important to exploit this diversity in developing better-adapted genotypes for future cropping environments. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
38. Origin and tectonic significance of corundum–kyanite–sapphirine amphibolites from the Variscan French Massif Central.
- Author
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BERGER, J ., FÉMÉNIAS, O., OHNENSTETTER, D., PLISSART, G., and MERCIER, J.-C. C.
- Subjects
- *
AMPHIBOLITES , *SERPENTINITE , *ECLOGITE , *GRANULITE , *OPHIOLITES - Abstract
The contact zone between two major allochthonous lithotectonic units in the French Massif Central (FMC) is characterized by the presence of corundum-bearing amphibolites associated with serpentinites, flaser-gabbros, eclogites and granulites. These unusual amphibolites are best preserved in the Western FMC, where they are found within the lower oceanic crust of the Limousin ophiolite. Mineralogical observations and thermodynamic modelling of the spinel–corundum–sapphirine–kyanite amphibolites in the CMASH system show that they were formed at peak P–T conditions around 800 °C/10 kbar in response to near isothermal burial followed by a retrogressive anticlockwise path. Metamorphic reactions are controlled both by modification of P–T conditions and by local chemical changes linked to fluid infiltration. Pargasite growth has been enhanced by infiltration of Ca- and Al-rich fluids whereas kyanite- and sapphirine-forming reactions are partly controlled by local inputs of MgO–SiO2 components, most probably during infiltration metasomatism. By analogy with worldwide ophiolites (Oman, Tethyan, Appalachian) and published numerical models, subduction of a still-hot oceanic ridge is proposed to form these Al-rich amphibolites from plagioclase-rich troctolites. The trace-element composition of high-Ti, fine-grained amphibolites (former fine-grained Fe–Ti gabbros) adjacent to the corundum-bearing ones, further indicates that the oceanic crust was initially created at a mid-ocean ridge (rather than within a back-arc basin), followed by the emplacement of supra-subduction zone-type magmas, probably due to intraoceanic subduction close to the ridge. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
39. Preferential sensitivity of hematopoietic (HPs) and mesenchymal (MPs) progenitors to fludarabine suggests impaired bone marrow niche and HP mobilization.
- Author
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Berger, M. G., Berger, J., Richard, C., Jeanpierre, S., Nicolini, F. E., Tournilhac, O., Michallet, M., and Satta, V. M.
- Subjects
- *
LETTERS to the editor , *BONE marrow - Abstract
A letter to the editor is presented which is about sensitivity of hematopoietic (HPs) and mesenchymal (MPs) progenitors to fludarabine with regard to HP mobilization and impaired bone marrow niche.
- Published
- 2008
- Full Text
- View/download PDF
40. A two-clock model of circadian timing in the immune system of mammals
- Author
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Berger, J.
- Subjects
- *
PINEAL gland , *HYPOTHALAMIC hormones , *SUPRACHIASMATIC nucleus , *IMMUNE system , *CIRCADIAN rhythms - Abstract
Abstract: It has been confirmed that clock genes, as well as the pineal hormone, have a role in the hypothalamic suprachiasmatic nucleus, the circadian endogenous pacemaker. It seems that the peripheral clock genes in the cells of the immune system subtly control biorhythms; their seeming lack of impact only showing that they work well. Some biorhythms even seem to be independent of a light/dark circadian regime. This apparent conflict in the mammalian time structure can be resolved by a two-clocks control model involving: (a) the endogenous gene clock, which is dominant in the neural system and (b) the exogenous clock of the immune system. Interactions between these two clocks can explain both the frequently observed individual differences in circadian rhythms and the subtle role of the peripheral clock genes. The endogenous clock facilitates an alternation in the immune system which counters external attacks in daytime and induces repair and advancement by night. [Copyright &y& Elsevier]
- Published
- 2008
- Full Text
- View/download PDF
41. Location of flux-induced vortex
- Author
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Berger, J., Kanda, A., Furugen, R., and Ootuka, Y.
- Subjects
- *
MESOSCOPIC phenomena (Physics) , *SUPERCONDUCTIVITY , *MAGNETIC flux , *VORTEX motion - Abstract
Abstract: We have obtained experimental evidence for a vortex that mediates between adjacent fluxoid states in a mesoscopic superconducting ring with nonuniform width. We have obtained information about the path of this vortex. For small fluxoid numbers the vortex crosses the sample through the narrowest part and for large fluxoid numbers through the widest part. We review our predictions for critical points. Our results are in agreement with the existent theory. [Copyright &y& Elsevier]
- Published
- 2008
- Full Text
- View/download PDF
42. A hybrid genetic approach for airborne sensor vehicle routing in real-time reconnaissance missions
- Author
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Berger, J., Barkaoui, M., and Boukhtouta, A.
- Subjects
- *
RADAR in aeronautics , *RECONNAISSANCE aircraft , *AIRBORNE operations (Military science) , *GENETIC algorithms - Abstract
Abstract: Past initiatives to address surveillance and reconnaissance mission planning mainly focused on low-level control aspects such as real-time path planning and collision avoidance algorithms in limited environment. However, few efforts have been spent on high-level real-time task allocation. It is believed that automated decision capabilities supporting real-time resource allocation for sensor control and interactions might significantly reduce user workload, focusing attention on alternate tasks and objectives while assigning hard computational tasks to artificial agents. In this paper, we propose a new hybrid genetic algorithm to solve the dynamic vehicle routing problem with time windows, in which a group of airborne sensors are engaged in a reconnaissance mission evolving in a dynamic uncertain environment involving known and unknown targets/threats. In that context, visiting a target may consist in carrying out a collection of subtasks such as search, detect, recognize and confirm suspected targets, discover and confirm new ones. The approach consists in concurrently evolving two populations of solutions to minimize total travel time and temporal constraint violation using genetic operators combining variations of key concepts inspired from routing techniques and search strategies. A least commitment principle in servicing scheduled customers is also exploited to potentially improve solution quality. [Copyright &y& Elsevier]
- Published
- 2007
- Full Text
- View/download PDF
43. Osmotic adjustment of chickpea ( Cicer arietinum) is not associated with changes in carbohydrate composition or leaf gas exchange under drought.
- Author
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Basu, P. S., Berger, J. D., Turner, N. C., Chaturvedi, S. K., Ali, M., and Siddique, K. H. M.
- Subjects
- *
CHICKPEA , *GENETICS , *OSMOSIS , *PLANT breeding , *CARBOHYDRATES , *GAS exchange in plants , *DROUGHTS - Abstract
Genetic differences in osmotic adjustment (OA) have been reported among chickpea ( Cicer arietinum) cultivars. In this study eight advanced breeding lines (ABLs) derived from a cross between CTS 60543 (high OA) and Kaniva (low OA) and Tyson (medium OA) and Kaniva, along with the parents, were evaluated for OA, leaf carbohydrate composition and leaf gas exchange under dryland field conditions in India. The water potential (WP) decreased to lower values (less than −2.5 MPa) in Tyson, M 110 and M 86 than in the other genotypes. With decrease in WP, OA increased by 0.5 MPa in Kaniva and CTS 60543 to 1.3 MPa in M 55. As the decrease in WP varied with genotype, when OA was regressed against WP M 39 and M 55 had greater increases in OA with decrease in WP than the remaining nine genotypes, including the parents. As WP decreased, leaf starch content decreased while total soluble sugars, hexoses and sucrose increased: the decrease in starch was much smaller in M 93 and M 129 than in Tyson and M 51, but genotypic differences could not be detected in the increase in total sugars, hexoses or sucrose. The rates of photosynthesis and transpiration decreased as the WP became more negative, but M 129 reached low rates of photosynthesis (2 μmol m−2 s−1) and transpiration at a WP of −1.7 MPa, whereas Tyson reached the same low rate at −2.4 MPa. While OA varied among the chickpea genotypes, the differences were not associated with the changes in carbohydrate composition or the rates of gas exchange at low values of WP. Further, the degree of OA of the 11 genotypes was not the same as when they were selected for differences in OA under rainout shelter conditions in the field in Australia, suggesting that OA may show poor stability depending upon the stress level, location or physiological stage of the plant. This suggests that OA is not a valuable drought-resistance trait to select for in chickpea breeding programmes. [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
- View/download PDF
44. Analysis of moiré data for near-interface cracks.
- Author
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Rozenburg, Keith, Berger, J. R., Martin, P. A., and Reimanis, Ivar
- Subjects
- *
MOIRE method , *COLLOCATION methods , *TUNGSTEN , *COPPER , *BOUNDARY element methods , *PHOTOELASTICITY - Abstract
The analysis of moiré data obtained in bimaterials with near-interface cracks is examined. To extract stress intensity factors, a collocation-type method is developed where Westergaard crack-tip expansions are used for displacements in the cracked portion of the bimaterial, expansions from the method of fundamental solutions are used for displacements in the uncracked portion of the bimaterial, and continuity conditions at the interface are used to couple the two expansions. Proof-of-principle numerical experiments performed on synthetic data from a boundary element analysis of a cracked bimaterial successfully demonstrated the analysis method. Mixed-mode stress intensity factors were then determined from actual moiré data obtained in a copper–tungsten specimen. [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
- View/download PDF
45. Exocrine pancreatic function in biliary tract pathology treated with the endoscopic methods.
- Author
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Wasielica-Berger, J., Długosz, J. W., Łaszewicz, W., Baniukiewicz, A., Werpachowska, I., Mroczko, B., and Dąbrowski, A.
- Subjects
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PANCREATIC diseases , *BILIOUS diseases & biliousness , *CLINICAL pathology , *ENDOSCOPIC surgery , *ENZYME-linked immunosorbent assay , *DIGESTIVE enzymes , *DIGESTIVE system diseases , *PANCREATIC acinar cells , *INFLAMMATION - Abstract
Purpose: Incidence of pancreatic exocrine insufficiency in biliary pathology is estimated for about 30%. The objective was to assess pancreatic exocrine function in biliary tract pathology (cholelithiasis, strictures) before and after endoscopic treatment. Patients and methods: Twenty-eight patients with choledocholithiasis and its complications (19F/9M; aging 31-90 years, median: 69 years) were evaluated. Fecal elastase 1 concentration was measured using ELISA, before, early, and 6-8 weeks after endoscopic treatment. The inflammatory response of pancreas to the treatment was also assessed. Results: Initial fecal elastase 1 concentration in patients (median 454 µg/g) was not significantly different as compared to the control (median 357 µg/g). Nine patients (32%) had low fecal elastase 1 concentration (below 250 µg/g) and out of them 6 had the concentration below 200 µg/g, suggesting impairment of exocrine pancreatic function. Endoscopic treatment was successful in 82% of patients. Pancreatic inflammatory response was noted only in one patient. After 6-8 weeks fecal elastase 1 concentration in the whole group of patients did not significantly change in comparison to the initial level. However, out of 9 patients with initially low fecal elastase 1 concentration (median 191 µg/g) at least in 6 pancreatic function improved (median 310 µg/g), P<0.001. Conclusion: One third of the patients with biliary pathology had a low fecal elastase 1 concentrations, suggesting pancreatic dysfunction. In at least 2/3 of these patients successful endoscopic treatment of biliary pathology resulted in the significant increase of fecal elastase 1 concentration. Therefore, an additional positive effect of such treatment in some patients, could be an improvement of the exocrine pancreatic dysfunction. [ABSTRACT FROM AUTHOR]
- Published
- 2007
46. Incorporation of the tidal model into the interdisciplinary plan of care – a program quality improvement project.
- Author
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Berger, J. L.
- Subjects
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HEALTH planning , *CLIENT-centered psychotherapy , *MENTAL health services , *PSYCHIATRIC nursing , *PSYCHIATRIC nurses , *MENTAL health personnel - Abstract
The Tidal Model was utilized in the development and implementation of an Interdisciplinary Care Plan (IPC) on an inpatient psychiatric unit at St. Joseph’s Healthcare Hamilton, Canada. Recovery, client-centered care and interdisciplinary team function were important concepts that were also integrated in the creation of a new care plan. The Tidal Model honors the person and the person’s story. This model focuses on engaging the person rather than an illness, with the goal of understanding the person’s present situation and his or her relationship with health and illness. Recovery focuses on moving beyond illness, and client centred care acknowledges clients as participants in their own care. As a program quality improvement initiative, the impact of the new IPC was evaluated. Feedback demonstrated that the IPC had a positive impact on both client and caregiver satisfaction, provided a better understanding of the client’s situation, and improved the team’s ability to document a care plan that reflected the client’s specific goals and the goals of the interdisciplinary team. The outcomes achieved through this project have provided support for the IPC along with the need for further evaluation. Our experience with the Tidal Model and the IPC has given voice to the patient’s story and helped facilitate their journey towards recovery. [ABSTRACT FROM AUTHOR]
- Published
- 2006
- Full Text
- View/download PDF
47. Predicting severity of haemophilia A and B splicing mutations by information analysis.
- Author
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Kodolitsch, Y., Berger, J., and Rogan, P. K.
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HEMOPHILIA , *BLOOD coagulation disorders , *HEMORRHAGE , *MESSENGER RNA , *GENETIC mutation , *PHENOTYPES - Abstract
Bleeding symptoms and clotting activity vary among mutations that alter mRNA splicing of either the factor VIII or factor IX genes. We analyzed splicing mutations in both genes for changes in individual information ( Ri, in bits) involving both donor or acceptor sites. Mutations with low or negative Ri values (<2.4 bits) or significant changes in Ri (Δ Ri ≥ 7 bits) exhibited either reduced protein activity, increased clotting time and bleeding frequency and were predictive of severe disease. Thus, information analysis of splicing mutations may be useful in predicting phenotypes in hemophilia. [ABSTRACT FROM AUTHOR]
- Published
- 2006
- Full Text
- View/download PDF
48. Use of W-boson longitudinal–transverse interference in top quark spin-correlation functions: II.
- Author
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Nelson, C. A., Berger, J. J., and Wickman, J. R.
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W bosons , *PARTICLES (Nuclear physics) , *INTERACTING boson models , *QUARKS , *LARGE Hadron Collider , *SPIN colliders , *SPINOR analysis - Abstract
This continuation of the derivation of general beam-referenced stage-two spin-correlation functions is for the analysis of top–antitop pair-production at the Tevatron and at the Large Hadron Collider. Both the gluon-production and the quark-production contributions are included for the charged-lepton-plus-jets reaction pp or $p\bar{p}\rightarrow t\bar{t}\rightarrow(W^+b)(W^-\bar{b})\rightarrow(l^+\nu b)(W^-\bar{b})$ . There is a simple 4-angle beam-referenced spin-correlation function for determination of the relative sign of or for measurement of a possible non-trivial phase between the two dominant $\lambda_b=-1/2$ helicity amplitudes for the $t\rightarrow W^+b$ decay mode. There is an analogous function and tests for $\bar{t}\rightarrow W^-\bar{b}$ decay. This signature requires use of the $(t\bar{t})_{\text{c.m.}}$ energy of the hadronically decaying W-boson, or the kinematically equivalent cosine of the polar angle of $W^\mp$ emission in the antitop (top) decay frame. Spinors and their outer-products are constructed so that the helicity-amplitude phase convention of Jacob and Wick can be used throughout for the fixing of the signs associated with this large W-boson longitudinal–transverse interference effect. [ABSTRACT FROM AUTHOR]
- Published
- 2006
- Full Text
- View/download PDF
49. Efficacy of combined iron and zinc supplementation on micronutrient status and growth in Vietnamese infants.
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Berger, J., Ninh, N. X., Khan, N. C., Nhien, N. V., Lien, D. K., Trung, N. Q., and Khoi, H. H.
- Subjects
- *
DIETARY supplements , *IRON , *ZINC , *MICRONUTRIENTS - Abstract
Objective:To evaluate the effect of combined iron–zinc supplementation on micronutrient status, growth and morbidity.Design:Randomized, double-masked, placebo-controlled supplementation trial.Setting:Rural district of Que Vo, in the Red River Delta in Vietnam.Subjects:A total of 915 breast-fed infants aged 4–7 months were included and 784 completed the study.Interventions:The Fe-group received daily and for a 6-month period 10 mg of iron, the Zn-group 10 mg zinc, the Fe–Zn group 10 mg iron+10 mg zinc and the placebo group a placebo. Hemoglobin (Hb), serum ferritin (SF) and zinc (SZn), and anthropometry were measured before and at the end of the intervention. Morbidity was recorded daily.Results:Changes of Hb and SF were higher in both Fe and Fe+Zn groups (respectively 22.6 and 20.6 g/l for Hb; 36.0 and 24.8 μg/l for SF) compared to Zn and placebo groups (Hb: 6.4 and 9.8 g/l; SF: −18.2 and −16.9 μg/l, P<0.0001). SZn increased more in Zn group (10.3 μmol/l) than in Fe+Zn group (8.0 μmol/l, P=0.03) and more in these groups compared to Fe and placebo groups (1.6 and 1.2 μmol/l, P<0.0001). Weight gain was higher in the Zn group. No significant effects of supplementations on growth in length or morbidity.Conclusions:Combined iron–zinc supplementation had a positive effect on iron and zinc status in infants. However, the positive effect of zinc alone on SZn and weight would indicate a negative interaction of iron when added to zinc supplements.Sponsorship:UNICEF New York.European Journal of Clinical Nutrition (2006) 60, 443–454. doi:10.1038/sj.ejcn.1602336; published online 23 November 2005 [ABSTRACT FROM AUTHOR]
- Published
- 2006
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50. FISSION COLLECTIVE DYNAMICS IN A MICROSCOPIC FRAMEWORK.
- Author
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GOUTTE, H., BERGER, J.-F., and GOGNY, D.
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NUCLEAR fission , *NUCLEAR reactions , *NUCLEAR forces (Physics) , *NUCLEAR physics , *PARTICLES (Nuclear physics) - Abstract
A time-dependent microscopic approach of the fission process based on the constrained HFB approach with the Gogny force and the Hill and Wheeler configuration mixing method is described. Recent results concerning fragment distributions (mass, kinetic and deformation energies) and other fragment observables in 238U obtained with such an approach are presented and discussed. [ABSTRACT FROM AUTHOR]
- Published
- 2006
- Full Text
- View/download PDF
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