941 research outputs found

    Uncertainty Considerations with the GRIM

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    Refractive index has been chosen as a comparison technique in glass analysis for many years. Hidden in this comparison is a quantitative measurement that requires the assessment of uncertainty. In this experiment, refractive index was performed on 63 samples from 41 sources of glass. Pairwise comparisons were calculated to illustrate the difference between using a conventional approach like standard deviation to using uncertainty. The amount of pairwise comparisons more than tripled from standard deviation to uncertainty showing the need to consider all possible sources of uncertainty in a refractive index measurement

    Atomic quantum gases in Kagom\'e lattices

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    We demonstrate the possibility of creating and controlling an ideal and \textit{trimerized} optical Kagom\'e lattice, and study the low temperature physics of various atomic gases in such lattices. In the trimerized Kagom\'e lattice, a Bose gas exhibits a Mott transition with fractional filling factors, whereas a spinless interacting Fermi gas at 2/3 filling behaves as a quantum magnet on a triangular lattice. Finally, a Fermi-Fermi mixture at half filling for both components represents a frustrated quantum antiferromagnet with a resonating-valence-bond ground state and quantum spin liquid behavior dominated by continuous spectrum of singlet and triplet excitations. We discuss the method of preparing and observing such quantum spin liquid employing molecular Bose condensates.Comment: 4 pages, 1 figure. Missing affiliations adde

    Atomic Fermi gas in the trimerized Kagom\'e lattice at the filling 2/3

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    We study low temperature properties of an atomic spinless interacting Fermi gas in the trimerized Kagom\'e lattice for the case of two fermions per trimer. The system is described by a quantum spin 1/2 model on the triangular lattice with couplings depending on bonds directions. Using exact diagonalizations we show that the system exhibits non-standard properties of a {\it quantum spin-liquid crystal}, combining a planar antiferromagnetic order with an exceptionally large number of low energy excitations.Comment: 4 pages & 4 figures + 2 tables, better version of Fig.

    Scaling of the Hysteresis Loop in Two-dimensional Solidification

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    The first order phase transitions between a two-dimensional (2d) gas and the 2d solid of the first monolayer have been studied for the noble gases Ar, Kr and Xe on a NaCl(100) surface in quasi-equilibrium with the three-dimensional gas phase. Using linear temperature ramps, we show that the widths of the hysteresis loops of these transitions as a function of the heating rate, r, scales with a power law r^alpha with alpha between 0.4 and 0.5 depending on the system. The hysteresis loops for different heating rates are similar. The island area of the condensed layer was found to grow initially with a t^4 time dependence. These results are in agreement with theory, which predicts alpha = 0.5 and hysteresis loop similarity.Comment: 4 pages, 5 figures, Revte

    Fa(c)t checking: how fatty acids shape metabolism and function of macrophages and dendritic cells

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    In recent years there have been major advances in our understanding of the role of free fatty acids (FAs) and their metabolism in shaping the functional properties of macrophages and DCs. This review presents the most recent insights into how cell intrinsic FA metabolism controls DC and macrophage function, as well as the current evidence of the importance of various exogenous FAs (such as polyunsaturated FAs and their oxidation products-prostaglandins, leukotrienes, and proresolving lipid mediators) in affecting DC and macrophage biology, by modulating their metabolic properties. Finally, we explore whether targeted modulation of FA metabolism of myeloid cells to steer their function could hold promise in therapeutic settings.Host-parasite interactio

    Performing Academic Practice: Using the Master Class to Build Postgraduate Discursive Competences

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    This is an Accepted Manuscript of an article published by Taylor & Francis in Journal of Geography in Higher Education on 27/04/2010, available online: https://www.tandfonline.com/doi/full/10.1080/03098260903502695How can we find ways of training PhD students in academic practices, while reflexively analysing how academic practices are performed? The paper’s answer to this question is based on evaluations from a British–Nordic master class. The paper discusses how master classes can be used to train the discursive skills required for academic discussion, commenting and reporting. Methods used in the master class are: performing and creative arts pedagogical exercises, the use of written provocations to elicit short papers, discussion group exercises, and training in reporting and in panel discussion facilitated by a meta-panel discussion. The authors argue that master classes have the potential to further develop advanced-level PhD training, especially through their emphasis on reflexive engagement in the performance of key academic skills

    Effect of Market Channel, Farm Scale, and Years in Production on Mid-Atlantic Vegetable Producers\u27 Knowledge and Implementation of Good Agricultural Practices

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    Foodborne illnesses associated with fresh produce have dramatically increased within the last decade. Good Agricultural Practices (GAP) were developed to address potential sources of pre-harvest microbial contamination, but certification remains low. The majority of mid-Atlantic vegetable farms are fresh market, but limited information is available about what on-farm production practices are being utilized to mitigate food safety risks. Our goal was to assess Maryland and Delaware vegetable producers\u27 understanding and implementation of GAP. An electronic survey on pre-harvest production practices was administered at commercial grower meetings in 2010 and 2013. A total of 313 surveys were analyzed, and Probit regression was used to estimate the average marginal effects of farm scale, years in production and market channel on the probability of using different on-farm food safety practices. Generally, food safety practices did not differ across farm scale or years in production. However, market channel did influence a grower\u27s decision to implement some food safety practices. Growers who marketed their produce primarily through wholesale channels were more likely to: have written policies for how they grew and handled their produce, test their irrigation water at least once a year for microbial contamination, or be GAP-certified. Economic constraints were not reported as the primary obstacle for GAP implementation in either survey. While more research is needed to better understand how market channel influences decision-making activities including on-farm food safety practices, this study highlights the complexity of the issue and the need for GAP educational programs to expand beyond a one-size-fits-all approach

    Critical Exponents of the Chiral Potts Model from Conformal Field Theory

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    The ZNZ_N-invariant chiral Potts model is considered as a perturbation of a ZNZ_N conformal field theory. In the self-dual case the renormalization group equations become simple, and yield critical exponents and anisotropic scaling which agree with exact results for the super-integrable lattice models. Although the continuum theory is not Lorentz invariant, it respects a novel type of space-time symmetry which allows for the observed spontaneous breaking of translational symmetry in the ground state. The continuum theory is shown to possess an infinite number of conserved charges on the self-dual line, which remain conserved when the theory is perturbed by the energy operator.Comment: 15 page
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