8,544 research outputs found

    Combination of a magnetic Feshbach resonance and an optical bound-to-bound transition

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    We use laser light near resonant with an optical bound-to-bound transition to shift the magnetic field at which a Feshbach resonance occurs. We operate in a regime of large detuning and large laser intensity. This reduces the light-induced atom-loss rate by one order of magnitude compared to our previous experiments [D.M. Bauer et al. Nature Phys. 5, 339 (2009)]. The experiments are performed in an optical lattice and include high-resolution spectroscopy of excited molecular states, reported here. In addition, we give a detailed account of a theoretical model that describes our experimental data

    Questioning and organization studies

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    This essay identifies a cleavage in the organisation literature that separates ‘questions’ and ‘questioning’ at a very fundamental philosophical level. On the one hand, the objective notion of ‘questions’ has already been well addressed within organization studies, evident in how scholars have scrutinized questions as objects of analysis; for example, paying close attention to the forms and functions of questions as instruments of research. More recently, the linguistic turn within the social sciences has influenced how organization studies researchers have considered organizations as discursive entities, with debate extending to the discursive nature of ‘questions’. On the other hand, the process of ‘questioning’ remains under-researched. From one perspective, questioning the process of questioning is challenging, but, as we submit, this is precisely where American pragmatism can be helpful. As we explore in this essay, the forward-looking quality of pragmatist inquiry is what motors the process of questioning. Our pragmatist-inflected argument is that questioning does not have to always serve critique and position building in the organization studies field. Rather, questioning out of curiosity can build new dialogue and open up new methodological avenues. This may help change the habitual ways in which we explore ideas, problems and situations in organization studies as well as lead to more democratic forms of organizing. Crucially, in this essay we are not looking for ultimate ‘answers’; rather we hope to excite discussion about questioning by giving prominence to something that is so ubiquitous and taken-for-granted as to be invisible to many of us as an object of inquiry

    Curved Gratings as Plasmonic Lenses for Linearly Polarised Light

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    The ability of curved gratings as sectors of concentric circular gratings to couple linearly polarized light into focused surface plasmons is investigated by theory, simulation and experiment. Curved gratings, as sectors of concentric circular gratings with four different sector angles, are etched into a 30-nm thick gold layer on a glass coverslip and used to couple linearly-polarised free space light at nm into surface plasmons. The experimental and simulation results show that increasing the sector angle of the curved gratings decreases the lateral spotsize of the excited surface plasmons, resulting in focussing of surface plasmons which is analogous to the behaviour of classical optical lenses. We also show that two faced curved gratings, with their groove radius mismatched by half of the plasmon wavelength (asymmetric configuration), can couple linearly-polarised light into a single focal spot of concentrated surface plasmons with smaller depth of focus and higher intensity in comparison to single-sided curved gratings. The major advantage of these structures is the coupling of linearly-polarised light into focused surface plasmons with access to and control of the plasmon focal spot, which facilitates potential applications in sensing, detection and nonlinear plasmonics.Comment: 15 pages and 12 figure

    Monitoring quantity and quality of pangasius pond effluent : report of a monitoring program and recommendations for certification

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    The quantity and quality of pangasius pond effluent was monitored by means of monthly sampling during a study conducted on four striped catfish farms located in the Mekong Delta, Vietnam. The study was undertaken to test the practical implications of the standards and guidelines with regard to catfish pond effluent that are at present developed by various certification programs for striped catfish production in Vietnam. The results showed a great variability twelve pangasius pond within the samples that were taken during one period of partial pond draining and refilling. The consequences of such variability with regard to the certification standards and guidelines are discussed and recommendations are given

    Effect of Pauli repulsion and transfer on fusion

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    The effect of the Pauli exclusion principle on the nucleus-nucleus bare potential is studied using a new density-constrained extension of the Frozen-Hartree-Fock (DCFHF) technique. The resulting potentials exhibit a repulsion at short distance. The charge product dependence of this Pauli repulsion is investigated. Dynamical effects are then included in the potential with the density-constrained time-dependent Hartree-Fock (DCTDHF) method. In particular, isovector contributions to this potential are used to investigate the role of transfer on fusion, resulting in a lowering of the inner part of the potential for systems with positive Q-value transfer channels.Comment: Proceedings of an invited talk given at FUSION17, Hobart, Tasmania, AU (20-24 February, 2017

    Epigenetics and Breast Cancers

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    Several of the active compounds in foods, poisons, drugs, and industrial chemicals may, by epigenetic mechanisms, increase or decrease the risk of breast cancers. Enzymes that are involved in DNA methylation and histone modifications have been shown to be altered in several types of breast and other cancers resulting in abnormal patterns of methylation and/or acetylation. Hypermethylation at the CpG islands found in estrogen response element (ERE) promoters occurs in conjunction with ligand-bonded alpha subunit estrogen receptor (Erα) dimers wherein the ligand ERα dimer complex acts as a transcription factor and binds to the ERE promoter. Ligands could be 17-β-estradiol (E2), phytoestrogens, heterocyclic amines, and many other identified food additives and heavy metals. The dimer recruits DNA methyltransferases which catalyze the transfer of methyl groups from S-adenosyl-L-methionine (SAM) to 5′-cytosine on CpG islands. Other enzymes are recruited to the region by ligand-ERα dimers which activate DNA demethylases to act simultaneously to increase gene expression of protooncogenes and growth-promoting genes. Ligand-ERα dimers also recruit histone acetyltransferase to the ERE promoter region. Histone demethylases such as JMJD2B and histone methyltransferases are enzymes which demethylate lysine residues on histones H3 and/or H4. This makes the chromatin accessible for transcription factors and enzymes

    Foreword

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    This work reports on the performances of ohmic contacts fabricated on highly p-type doped 4H-SiC epitaxial layer selectively grown by vapor-liquid-solid transport. Due to the very high doping level obtained, the contacts have an ohmic behavior even without any annealing process. Upon variation of annealing temperatures, it was shown that both 500 and 800 °C annealing temperature lead to a minimum value of the Specific Contact Resistance (SCR) down to 1.3×10−6 Ω⋅cm2. However, a large variation of the minimum SCR values has been observed (up to 4×10−4 Ω⋅cm2). Possible sources of this fluctuation have been also discussed in this paper

    Multipole Expansion for the Electron-Nucleus Scattering at High Energies in the Unified Electroweak Theory

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    The article presents the multipole expansion for the electron-nucleus scattering cross section at high energies within the framework of the unified electroweak theory. The electroweak currents of the nucleus are expanded into simple components with definite angular momentum, which are called the multipole form factors. The multipole expansion of the cross section is a consequence of the above expansion. Besides the familiar electromagnetic form factors, there are weak form factors related to weak interactions, corresponding to the vector and axial (pseudovector) weak currents. We do not use the impulse approximation, the multipole form factors are calculated directly, using only the Born approximation. We will present some examples in the next paper.Comment: 7 pages, 0 figur
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