203 research outputs found

    Monopole-driven shell evolution below the doubly magic nucleus Sn 132 explored with the long-lived isomer in Pd 126

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    A new isomer with a half-life of 23.0(8) ms has been identified at 2406 keV in Pd126 and is proposed to have a spin and parity of 10+ with a maximally aligned configuration comprising two neutron holes in the 1h11/2 orbit. In addition to an internal-decay branch through a hindered electric octupole transition, β decay from the long-lived isomer was observed to populate excited states at high spins in Ag126. The smaller energy difference between the 10+ and 7- isomers in Pd126 than in the heavier N=80 isotones can be interpreted as being ascribed to the monopole shift of the 1h11/2 neutron orbit. The effects of the monopole interaction on the evolution of single-neutron energies below Sn132 are discussed in terms of the central and tensor forces

    New isomers in 125 Pd 79 and 127 Pd 81 : Competing proton and neutron excitations in neutron-rich palladium nuclides towards the N=82 shell closure

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    The neutron-rich isotopes of palladium have attracted considerable interest in terms of the evolution of the neutron shell closure and its influence on the r-process nucleosynthesis. In this Letter, we present the first spectroscopic information on the excited states in 125Pd79 and 127Pd81 studied using the EURICA γ-ray spectrometer, following production via in-flight fission of a high-intensity 238U beam at the RIBF facility. New isomeric states with half-lives of 144(4) ns and 39(6) μs have been assigned spins and parities of () and () in 125Pd and 127Pd, respectively. The observed level properties are compared to a shell-model calculation, suggesting the competition between proton excitations and neutron excitations in the proton-hole and neutron-hole systems in the vicinity of the doubly magic nucleus 132Sn.Part of the WAS3ABi was supported by the Rare Isotope Science Project which is funded by MSIP and NRF of Korea. This work was supported by the Priority Centers Research Program in Korea (2009-0093817), OTKA contract number K100835, the U.S. DOE, Office of Nuclear Physics (Contract No. DE-AC02-06CH11357), NRF-2016R1A5A1013277 and NRF-2013M7A1A1075764, the Spanish Ministerio de Economía y Competitividad under contract FPA2017-84756-C4-2-P, the European Commission through the Marie Curie Actions call FP7-PEOPLE-2011-IEF (Contract No. 300096), German BMBF under Contract No: 05P12PKFNE, JSPS KAKENHI Grant No. 24740188 and 25247045, the National Natural Science Foundation of China (Nos. 11505302, 11575112), the National Key Program for S&T Research and Development (No. 2016YFA0400501), and STFC (UK)

    A Multi-Epoch VLBI Survey of the Kinematics of CJF Sources; Part I: Model-Fit Parameters and Maps

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    Context: This is the first of a series of papers presenting VLBI observations of the 293 Caltech-Jodrell Bank Flat-Spectrum (hereafter CJF) sources and their analysis. Aims: One of the major goals of the CJF is to make a statistical study of the apparent velocities of the sources. Methods: We have conducted global VLBI and VLBA observations at 5 GHz since 1990, accumulating thirteen separate observing campaigns. Results: We present here an overview of the observations, give details of the data reduction and present the source parameters resulting from a model-fitting procedure. For every source at every observing epoch, an image is shown, built up by restoring the model-fitted components, convolved with the clean beam, into the residual image, which was made by Fourier transforming the visibility data after first subtracting the model-fitted components in the uv-plane. Overplotted we show symbols to represent the model components. Conclusions: We have produced VLBI images of all but 5 of the 293 sources in the complete CJF sample at several epochs and investigated the kinematics of 266 AGN.Comment: Figure 1 and Table 2 are only available in electronic form at the CDS and soon at http://www.mpifr-bonn.mpg.de/staff/sbritzen/cjf.htm

    Bipartite Entanglement in Continuous-Variable Cluster States

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    We present a study of the entanglement properties of Gaussian cluster states, proposed as a universal resource for continuous-variable quantum computing. A central aim is to compare mathematically-idealized cluster states defined using quadrature eigenstates, which have infinite squeezing and cannot exist in nature, with Gaussian approximations which are experimentally accessible. Adopting widely-used definitions, we first review the key concepts, by analysing a process of teleportation along a continuous-variable quantum wire in the language of matrix product states. Next we consider the bipartite entanglement properties of the wire, providing analytic results. We proceed to grid cluster states, which are universal for the qubit case. To extend our analysis of the bipartite entanglement, we adopt the entropic-entanglement width, a specialized entanglement measure introduced recently by Van den Nest M et al., Phys. Rev. Lett. 97 150504 (2006), adapting their definition to the continuous-variable context. Finally we add the effects of photonic loss, extending our arguments to mixed states. Cumulatively our results point to key differences in the properties of idealized and Gaussian cluster states. Even modest loss rates are found to strongly limit the amount of entanglement. We discuss the implications for the potential of continuous-variable analogues of measurement-based quantum computation.Comment: 22 page

    Identification and quantification of microplastics in wastewater using focal plane array-based reflectance micro-FT-IR imaging

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    Microplastics (<5 mm) have been documented in environmental samples on a global scale. While these pollutants may enter aquatic environments via wastewater treatment facilities, the abundance of microplastics in these matrices has not been investigated. Although efficient methods for the analysis of microplastics in sediment samples and marine organisms have been published, no methods have been developed for detecting these pollutants within organic-rich wastewater samples. In addition, there is no standardized method for analyzing microplastics isolated from environmental samples. In many cases, part of the identification protocol relies on visual selection before analysis, which is open to bias. In order to address this, a new method for the analysis of microplastics in wastewater was developed. A pretreatment step using 30% hydrogen peroxide (H2O2) was employed to remove biogenic material, and focal plane array (FPA)-based reflectance micro-Fourier-transform (FT-IR) imaging was shown to successfully image and identify different microplastic types (polyethylene, polypropylene, nylon-6, polyvinyl chloride, polystyrene). Microplastic-spiked wastewater samples were used to validate the methodology, resulting in a robust protocol which was nonselective and reproducible (the overall success identification rate was 98.33%). The use of FPA-based micro-FT-IR spectroscopy also provides a considerable reduction in analysis time compared with previous methods, since samples that could take several days to be mapped using a single-element detector can now be imaged in less than 9 h (circular filter with a diameter of 47 mm). This method for identifying and quantifying microplastics in wastewater is likely to provide an essential tool for further research into the pathways by which microplastics enter the environment.This work is funded by a NERC (Natural Environment Research Council) CASE studentship (NE/K007521/1) with contribution from industrial partner Fera Science Ltd., United Kingdom. The authors would like to thank Peter Vale, from Severn Trent Water Ltd, for providing access to and additionally Ashley Howkins (Brunel University London) for providing travel and assistance with the sampling of the Severn Trent wastewater treatment plant in Derbyshire, UK. We are grateful to Emma Bradley and Chris Sinclair for providing helpful suggestions for our research

    Preplant 1,3-D treatments test well for perennial crop nurseries, but challenges remain

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    Preplant fumigation with methyl bromide commonly is used in open-field perennial crop nurseries in California for control of plant-parasitic nematodes, pathogens and weeds. Because this fumigant is being phased out, alternatives are needed to ensure the productivity of the perennial crop nursery industry as well as the ornamental, orchard and vineyard production systems that depend on clean planting stock. As part of the USDA Area-Wide Pest Management Program for Integrated Methyl Bromide Alternatives, several perennial crop nursery projects were conducted in California from 2007 to 2011 to test and demonstrate registered alternative fumigants and application techniques that maximize performance and minimize environmental impacts. The project was designed to evaluate shank application and soil surface sealing methods intended to reduce aboveground emission and improve soil performance of 1,3-dichloropropene, a leading methyl bromide alternative for nurseries. In these garden rose and tree nursery experiments, 1,3-dichloropropene treatments performed well regardless of application techniques. In this article, we highlight recent research and discuss the significance and remaining challenges for adoption of methyl bromide alternatives in this unique nursery stock production system

    Shape evolution in 116,118 Ru: Triaxiality and transition between the O(6) and U(5) dynamical symmetries

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    116Ru and 118Ru have been studied via β-delayed γ-ray spectroscopy of nuclei produced in fragmentation reactions at the Radioactive Ion-Beam Factory (RIBF) facility. Level schemes with positive-parity states up to spin J=6 have been constructed. The re

    The SPECFIND V2.0 catalogue of radio cross-identifications and spectra. SPECFIND meets the Virtual Observatory

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    The new release of the SPECFIND radio cross-identification catalogue, SPECFIND V2.0, is presented. It contains 107488 cross-identified objects with at least three radio sources observed at three independent frequencies. Compared to the previous release the number of entry radio catalogues is increased from 20 to 97 containing 115 tables. This large increase was only made possible by the development of four tools at CDS which use the standards and infrastructure of the Virtual Observatory (VO). This was done in the framework of the VO-TECH European Design Study of the Sixth Framework Program. We give an overview of the different classes of radio sources that a user can encounter. Due to the increase of frequency coverage of the input radio catalogues, this release demonstrates that the SPECFIND algorithm is able to detect spectral breaks around a frequency of ~1 GHz.Comment: 11 pages, 10 figures, accepted for publication in A&

    Money, Love, and Fragile Reciprocity in Contemporary Havana, Cuba

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    Among low-income Havana residents, men frequently give money and other forms of material support to women in whom they have a romantic interest. For women, men's material contributions are expressions of responsibility and care. While men share this view to a degree, they sometimes have more ambiguous emotions regarding such practices. These tensions in different views of gendered reciprocity are influenced by large-scale changes that have taken place in Cuban society since the 1990s. Although, traditionally, state socialism has embraced ideas of gender egalitarianism and women's independent income, the post-Soviet period has seen the emergence of new inequalities, dependencies, and marginalizations that threaten earlier, socialist understandings of intimacy. The importance that women currently place on material wealth in terms of their views of a desirable partner highlights the gendered consequences of Cuba's contemporary economic transformations and their complex interplay with individuals' aspirations for love.Peer reviewe
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