601 research outputs found

    Possible experimental signature of octupole correlations in the 02+^+_2 states of the actinides

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    JÏ€J^{\pi}= 0+^+ states have been investigated in the actinide nucleus 240{}^{240}Pu up to an excitation energy of 3 MeV with a high-resolution (p,t) experiment at EpE_{p}= 24 MeV. To test the recently proposed JÏ€J^{\pi}= 02+^+_2 double-octupole structure, the phenomenological approach of the spdf-interacting boson model has been chosen. In addition, the total 0+^+ strength distribution and the 0+0^+ strength fragmentation have been compared to the model predictions as well as to the previously studied (p,t) reactions in the actinides. The results suggest that the structure of the 02+^+_2 states in the actinides might be more complex than the usually discussed pairing isomers. Instead, the octupole degree of freedom might contribute significantly. The signature of two close-lying 0+^+ states below the 2-quasiparticle energy is presented as a possible manifestation of strong octupole correlations in the structure of the 02+^+_2 states in the actinides.Comment: 6 pages, 5 figures, published in Phys. Rev. C 88, 041303(R) (2013

    Radio Loud AGN in the Context of the Eigenvector 1 Parameter Space

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    We consider the properties of radio-loud (RL) AGN in the context of the Eigenvector 1 (E1) parameter space. RL sources show a restricted E1 parameter space occupation relative to the radio-quiet (RQ) majority. The Fanaroff-Riley II ``parent population'' of relatively un-boosted RL sources (median radio/optical flux ratio ~490) shows the most restricted occupation. RL sources have different broad line properties (and inferred black hole masses and Eddington ratios). FWHM H_beta for the broad line component in RL sources are at least twice as large as the RQ majority. The average broad FeII emission line strength is also about half that for RQ sources. Our sample suggests that the RL cutoff occurs near R_k=70 or logP(6cm)=32.0 ergs/s/Hz. Sources below this cutoff are RQ although we cannot rule out the existence of a distinct intermediate population. We show that the Doppler boosted core-dominated RL sources (median flux ratio ~1000) lie towards smaller FWHM(H_beta_bc) and stronger FeII in E1 as expected if the lines arise in an accretion disk. Our subsample of superluminal sources, with orientation inferred from the synchrotron self Compton model, reinforce this general E1 trend and allow us to estimate the role of source orientation in driving E1 domain occupation.Comment: 9 pages, 3 figures, accepted for publication in ApJ

    3C 57 as an Atypical Radio-Loud Quasar: Implications for the Radio-Loud/Radio-Quiet Dichotomy

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    Lobe-dominated radio-loud (LD RL) quasars occupy a restricted domain in the 4D Eigenvector 1 (4DE1) parameter space which implies restricted geometry/physics/kinematics for this subclass compared to the radio-quiet (RQ) majority of quasars. We discuss how this restricted domain for the LD RL parent population supports the notion for a RQ-RL dichotomy among Type 1 sources. 3C 57 is an atypical RL quasar that shows both uncertain radio morphology and falls in a region of 4DE1 space where RL quasars are rare. We present new radio flux and optical spectroscopic measures designed to verify its atypical optical/UV spectroscopic behaviour and clarify its radio structure. The former data confirms that 3C 57 falls off the 4DE1 quasar "main sequence" with both extreme optical FeII emission (R_{FeII} ~ 1) and a large CIV 1549 profile blueshift (~ -1500 km/s). These parameter values are typical of extreme Population A sources which are almost always RQ. New radio measures show no evidence for flux change over a 50+ year timescale consistent with compact steep-spectrum (CSS or young LD) over core-dominated morphology. In the 4DE1 context where LD RL are usually low L/L_{Edd} quasars we suggest that 3C 57 is an evolved RL quasar (i.e. large Black Hole mass) undergoing a major accretion event leading to a rejuvenation reflected by strong FeII emission, perhaps indicating significant heavy metal enrichment, high bolometric luminosity for a low redshift source and resultant unusually high Eddington ratio giving rise to the atypical CIV 1549.Comment: Accepted for publication in MNRAS; 10 pages, 6 figures, 4 table

    The influence of different prefermentative maceration processes and tartaric stabilization treatments on the color, cation content and other physico-chemical parameters of 'Băbească neagră' rosé wines

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    This study enhances knowledge in the physicochemical and color parameters of rosé wines produced by the prefermentative maceration of native Romanian 'Băbească neagră' (Vitis vinifera L.) grape varieties, both before and after tartaric stabilization treatments by the contact procedure in an MK70 ultra-refrigerator. One variety was prepared without maceration as a control sample and the other was subjected to the maceration process for one of the following seven periods of time: 3.5 hours, 7 hours, 10.5 hours, 14 hours, 17.5 hours, 21 hours and 24.5 hours. The prefermentative maceration process exerts a significant influence on the amount of volatile acids, on the pH, conductivity and the K+ cation. The phenolic compound content, the chromatic parameters and the cation content of wines are significantly influenced by both prefermentative maceration and tartaric stabilization. The multifactor ANOVA tests prove that there is an interaction for all parameters except for total acidity.

    Simulation of Subsurface Drainage in the Sugarcane Crop under Different Spacing and Drain Depths

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    Agricultural land drainage is an instrument for growing production and a tool for the conservation of land resources. The performance of land drainage systems is thus critical for achieving sustainable agricultural production Recently, many types of software have been developed in this field for modeling and simulating the performance of these systems. SISDRENA is a simulation model of the performance of underground drainage systems. The main objectives of this paper are to simulate different combination of depths and spaces between drains and to analyze their impact on potential sugarcane productivity in the western plains of Venezuela using a land drainage system model. Therefore, three climatic scenarios were defined by annual precipitation: dry years (25% below average), normal (mean) and humid (75% above average). The scenarios were implemented in three different soil types: sandy loam, loam and silt loam, with a hydraulic conductivity of 0.19, 0.26 and 0.04 m day−1, respectively. The simulation of the yield related to soil deficit (YRD) and water stress (YRW) indicated that the highest yields were reached for the larger spacing between drains and the high conductivity hydraulic of soils. In relation to the average relative productivity (YT), it was shown that in soils with a greater water retention capacity there is an inversely proportional relationship between the spacing between drains and the productivity. We concluded that in order to reach the maximum sugarcane yield, the effect of hydraulic conductivity is more important than the changes in the precipitation pattern

    Uncovering demographic trends and recent urban expansion in metropolitan regions. A paradigmatic case study

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    While urbanization trends have been characterized for a long time by deconcentration of inner cities with expansion of low-density settlements, economic repolarization leading to re-urbanization and recovery of central districts are now counterbalancing population shrinkage in compact urban areas and slowing down suburban growth. In this context, the recent demographic evolution of a large metropolis such as Athens (Greece)-following expansion, crisis, and a more subtle economic recovery-may reveal original relationships between form and functions at the base of recent urban growth. Based on an exploratory analysis of demographic indicators on a metropolitan and urban scale, the present study provides an updated and integrated knowledge framework that confirms and integrates the most recent urban trends in southern Europe. Documenting the emergence of more individualized paths of urban expansion at the local scale (recovery of the historic center, shrinkage of semicentral neighborhoods, 'reverse gentrification' of disadvantaged peripheral areas, late suburbanization of accessible peripheral areas), results of the present study justify an ad hoc analysis of metropolitan growth based on demographic indicators as a proxy for sustainable land management and local development

    Octupole correlations in positive-parity states of rare-earth and actinide nuclei

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    In this contribution, further evidence of the importance of multiphonon-octupole excitations to describe experimental data in the rare earths and actinides will be presented. First, new results of a (p, t) experiment at the Q3D magnetic spectrograph in Munich will be discussed, which was performed to selectively excite J(pi) = 0(+) states in Pu-240. spd f interacting boson model (IBM) calculations suggest that the previously proposed double-octupole phonon nature of the J(pi) = 0(2)(+) state is not in conflict with its strong (p, t) population. Second, the framework of the IBM has been adopted for the description of experimental observables related to octupole excitations in the rare earths. Here, the IBM is able to describe the signature splitting for positive- and negative-parity states when multi-dipole and multi-octupole bosons are included. The present study might support the idea of octupole-phonon condensation at intermediate spin (J(pi) = 10(+)) leading to the change in yrast structure observed in Nd-146
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