1,266 research outputs found

    Prospects for high-resolution microwave spectroscopy of methanol in a Stark-deflected molecular beam

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    Recently, the extremely sensitive torsion-rotation transitions in methanol have been used to set a tight constraint on a possible variation of the proton-to-electron mass ratio over cosmological time scales. In order to improve this constraint, laboratory data of increased accuracy will be required. Here, we explore the possibility for performing high-resolution spectroscopy on methanol in a Stark-deflected molecular beam. We have calculated the Stark shift of the lower rotational levels in the ground torsion-vibrational state of CH3OH and CD3OH molecules, and have used this to simulate trajectories through a typical molecular beam resonance setup. Furthermore, we have determined the efficiency of non-resonant multi-photon ionization of methanol molecules using a femtosecond laser pulse. The described setup is in principle suited to measure microwave transitions in CH3OH at an accuracy below 10^{-8}

    An AC electric trap for ground-state molecules

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    We here report on the realization of an electrodynamic trap, capable of trapping neutral atoms and molecules in both low-field and high-field seeking states. Confinement in three dimensions is achieved by switching between two electric field configurations that have a saddle-point at the center of the trap, i.e., by alternating a focusing and a defocusing force in each direction. AC trapping of 15ND3 molecules is experimentally demonstrated, and the stability of the trap is studied as a function of the switching frequency. A 1 mK sample of 15ND3 molecules in the high-field seeking component of the |J,K>=|1,1> level, the ground-state of para-ammonia, is trapped in a volume of about 1 mm^3

    Robust Constraint on a Drifting Proton-to-Electron Mass Ratio at z=0.89 from Methanol Observation at Three Radio Telescopes

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    A limit on a possible cosmological variation of the proton-to-electron mass ratio μ\mu is derived from methanol (CH3_3OH) absorption lines in the benchmark PKS1830-211 lensing galaxy at redshift z=0.89z = 0.89 observed with the Effelsberg 100-m radio telescope, the Institute de Radio Astronomie Millim\'{e}trique 30-m telescope, and the Atacama Large Millimeter/submillimeter Array. Ten different absorption lines of CH3_3OH covering a wide range of sensitivity coefficients KμK_{\mu} are used to derive a purely statistical 1-σ\sigma constraint of Δμ/μ=(1.5±1.5)×107\Delta\mu/\mu = (1.5 \pm 1.5) \times 10^{-7} for a lookback time of 7.5 billion years. Systematic effects of chemical segregation, excitation temperature, frequency dependence and time variability of the background source are quantified. A multi-dimensional linear regression analysis leads to a robust constraint of Δμ/μ=(1.0±0.8stat±1.0sys)×107\Delta\mu/\mu = (-1.0 \pm 0.8_{\rm stat} \pm 1.0_{\rm sys}) \times 10^{-7}.Comment: 5 pages, 3 figures. Published in PR

    Air Quality Monitoring in the Southeast Community in the City of Newport News, VA

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    Purpose: The objective of this study was to assess air quality in the Southeast Community of Newport News, VA by monitoring air pollutants, including PM2.5, PM10, VOCs, NO2, and SO2. Currently, there is a lack of community specified air quality data in Newport News despite observed environmental degradation and public health problems. Methods: Three air sampling sites were located within residential areas of the Southeast Community, while four industrial air sampling sites were chosen based on proximity to potential pollution sources, including traffic emissions, the coal pier, and industrial activities. All of the industrial sites were located on the boundaries of the community. Each site was continuously monitored for eight hours per day and was sampled at least twice for data accuracy. A GRIMM PM monitor was used to measure PM2.5 and PM10 and a MultiRae PRO (model PGM-6248) was used to continuously quantify VOCs, NO2, and SO2. Results: While average PM2.5 and PM10 from all sample sites were within the acceptable range of EPA air quality criteria, averaged VOCs in the industrial and highway areas were higher than those in the community. Conclusion: The findings of this research suggest a need for long-term monitoring air quality with a series of air pollutants in the community

    A stringent limit on a drifting proton-to-electron mass ratio from alcohol in the early Universe

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    The standard model of physics is built on the fundamental constants of nature, but it does not provide an explanation for their values, nor requires their constancy over space and time. Here, we set a limit on a possible cosmological variation of the proton-to-electron mass ratio μ by comparing transitions in methanol observed in the early universe with those measured in the laboratory. Based on radio-astronomical observations of PKS1830-211, we deduced a constraint of ∆μ/μ = (0.0 ± 1.0) × 10−7 at redshift z = 0.89, corresponding to a look-back time of 7 billion years. This is consistent with a null result

    Rotational Cooling of Polar Molecules by Stark-tuned Cavity Resonance

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    A general scheme for rotational cooling of diatomic heteronuclear molecules is proposed. It uses a superconducting microwave cavity to enhance the spontaneous decay via Purcell effect. Rotational cooling can be induced by sequentially tuning each rotational transition to cavity resonance, starting from the highest transition level to the lowest using an electric field. Electrostatic multipoles can be used to provide large confinement volume with essentially homogeneous background electric field.Comment: 10 pages, 6 figure

    Effects of transportation, handling and environment on slaughter cattle. I, Weight loss and carcass yield

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    Includes bibliographical references (page 11)

    Young people today: news media, policy and youth justice

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    The new sociology of childhood sees children as competent social agents with important contributions to make. And yet the phase of childhood is fraught with tensions and contradictions. Public policies are required, not only to protect children, but also to control them and regulate their behaviour. For children and young people in the UK, youth justice has become increasingly punitive. At the same time, social policies have focused more on children's inclusion and participation. In this interplay of conflict and contradictions, the role the media play is critical in contributing to the moral panic about childhood and youth. In this article, we consider media representations of “antisocial” children and young people and how this belies a moral response to the nature of contemporary childhood. We conclude by considering how a rights-based approach might help redress the moralised politics of childhood representations in the media

    Studies on Soil Transmitted Helminthic Infection Among Coal Miners in Sawah Lunto, West Sumatra

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    Prevalensi cacing Perut diantara karyawan tambang batu bara Ombilin Sawah Lunto adalah 91,2 persen, 39,8 persen dan 13,persen masing-masing untuk cacing tambang, Ascaris lumbricoides dan Trichuris trichiura. Sebagian besar karyawan tambang bati bara ini menderita anemia (hanya 13,3 persen diantara mereka yang mempunyai kadar haemoglobin dalam batas-batas normal). Ukuran persen diantara mereka yang mempunyai kadar haemoglobin dalam batas-batas normal). Ukuran Unthropometrik menunjukkan bahwa hanya 62,5 persen berat badak untuk tinggi badan karyawan tambang ini termasuk kategori 90 persen atau lebih Standard nasional yang diusulkan. Percobaan pengobatan dengan menggunakan tetramisole (ascaridil) menunjukkan bahwa obat ini memberikan hasil yang memuaskan hanya untuk infestasi A. lumbricoides
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