1,984 research outputs found

    The Hamiltonian Approach to Yang-Mills (2+1): An Expansion Scheme and Corrections to String Tension

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    We carry out further analysis of the Hamiltonian approach to Yang-Mills theory in 2+1 dimensions which helps to place the calculation of the vacuum wave function and the string tension in the context of a systematic expansion scheme. The solution of the Schrodinger equation is carried out recursively. The computation of correlators is re-expressed in terms of a two-dimensional chiral boson theory. The effective action for this theory is calculated to first order in our expansion scheme and to the fourth order in a kinematic expansion parameter. The resulting corrections to the string tension are shown to be very small, in the range -0.3% to -2.8%, moving our prediction closer to the recent lattice estimates.Comment: 33 pages, 10 figure

    Counting chiral primaries in N=1 d=4 superconformal field theories

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    I derive a procedure to count chiral primary states in N=1 superconformal field theories in four dimensions. The chiral primaries are counted by putting the N=1 field theory on S^3 X R. I also define an index that counts semi-short multiplets of the superconformal theory. I construct N=1 supersymmetric Lagrangians on S^3 X R for theories which are believed to flow to a conformal fixed point in the IR. For ungauged theories I reduce the field theory to a supersymmetric quantum mechanics, whereas for gauge theories I use chiral ring arguments. I count chiral primaries for SU(2) SYM with three flavors and its Seiberg dual. Those two results agree provided a new chiral ring relation holds.Comment: 34 pages, significant revisio

    ADVISE: Symbolism and External Knowledge for Decoding Advertisements

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    In order to convey the most content in their limited space, advertisements embed references to outside knowledge via symbolism. For example, a motorcycle stands for adventure (a positive property the ad wants associated with the product being sold), and a gun stands for danger (a negative property to dissuade viewers from undesirable behaviors). We show how to use symbolic references to better understand the meaning of an ad. We further show how anchoring ad understanding in general-purpose object recognition and image captioning improves results. We formulate the ad understanding task as matching the ad image to human-generated statements that describe the action that the ad prompts, and the rationale it provides for taking this action. Our proposed method outperforms the state of the art on this task, and on an alternative formulation of question-answering on ads. We show additional applications of our learned representations for matching ads to slogans, and clustering ads according to their topic, without extra training.Comment: To appear, Proceedings of the European Conference on Computer Vision (ECCV

    Evaluation and critical analysis of the Chinese porcelains in the Whitwell collection Tatham Art Gallery: Pietermaritzburg.

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    Thesis (M.A.F.A)-University of Natal, Pietermaritzburg, 2002.The first chapter is a broad review of the recent history of Chinese porcelain from the Ming period to the present day. It includes remarks on the ceramics town of Jingdezhen and on aspects of materials, construction techniques, glazing and enamelling as well as a brief summary of the types of wares. The second chapter is divided into two parts. The first part introduces the formation of the Tatham Art Gallery and the Whitwell Collection. The second part focuses, firstly, on the blue and white porcelain, secondly, on the enamelled porcelain. The pieces are individually physically examined and catalogued under these headings: General description, rim, foot ring, construction, iconography and motifs, glazes, marks and date. The last chapter compares the blue and white pieces, the enamelled pieces and both pieces. This chapter suggests the qualities and special attributes of the wares such as brush marks

    Yang-Mills Theory in 2+1 Dimensions: Coupling of Matter Fields and String-breaking Effects

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    We explore further the Hamiltonian formulation of Yang-Mills theory in 2+1 dimensions in terms of gauge-invariant matrix variables. Coupling to scalar matter fields is discussed in terms of gauge-invariant fields. We analyze how the screening of adjoint (and other screenable) representations can arise in this formalism. A Schrodinger equation is then derived for the gluelump states which are the daughter states when an adjoint string breaks. A variational solution of this Schrodinger equation leads to an analytic estimate of the string-breaking energy which is within 8.8% of the latest lattice estimates.Comment: 31 pages, 1 figure, minor comments, references added, final version to appear in Nucl.Phys.

    Missing.... presumed at random: cost-analysis of incomplete data

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    When collecting patient-level resource use data for statistical analysis, for some patients and in some categories of resource use, the required count will not be observed. Although this problem must arise in most reported economic evaluations containing patient-level data, it is rare for authors to detail how the problem was overcome. Statistical packages may default to handling missing data through a so-called complete case analysis, while some recent cost-analyses have appeared to favour an available case approach. Both of these methods are problematic: complete case analysis is inefficient and is likely to be biased; available case analysis, by employing different numbers of observations for each resource use item, generates severe problems for standard statistical inference. Instead we explore imputation methods for generating replacement values for missing data that will permit complete case analysis using the whole data set and we illustrate these methods using two data sets that had incomplete resource use information

    A Randomized Controlled Trial to Determine Whether Beta-Hydroxy-Beta-Methylbutyrate and/or Eicosapentaenoic Acid Improves Diaphragm and Quadriceps Strength in Critically Ill Mechanically Ventilated Patients

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    BACKGROUND: Intensive care unit acquired weakness is a serious problem, contributing to respiratory failure and reductions in ambulation. Currently, there is no pharmacological therapy for this condition. Studies indicate, however, that both beta-hydroxy-beta-methylbutyrate (HMB) and eicosapentaenoic acid (EPA) increase muscle function in patients with cancer and in older adults. The purpose of this study was to determine whether HMB and/or EPA administration would increase diaphragm and quadriceps strength in mechanically ventilated patients. METHODS: Studies were performed on 83 mechanically ventilated patients who were recruited from the Medical Intensive Care Units at the University of Kentucky. Diaphragm strength was assessed as the trans-diaphragmatic pressure generated by supramaximal magnetic phrenic nerve stimulation (PdiTw). Quadriceps strength was assessed as leg force generated by supramaximal magnetic femoral nerve stimulation (QuadTw). Diaphragm and quadriceps thickness were assessed by ultrasound. Baseline measurements of muscle strength and size were performed, and patients were then randomized to one of four treatment groups (placebo, HMB 3 gm/day, EPA 2 gm/day and HMB plus EPA). Strength and size measurements were repeated 11 days after study entry. ANCOVA statistical testing was used to compare variables across the four experimental groups. RESULTS: Treatments failed to increase the strength and thickness of either the diaphragm or quadriceps when compared to placebo. In addition, treatments also failed to decrease the duration of mechanical ventilation after study entry. CONCLUSIONS: These results indicate that a 10-day course of HMB and/or EPA does not improve skeletal muscle strength in critically ill mechanically ventilated patients. These findings also confirm previous reports that diaphragm and leg strength in these patients are profoundly low. Additional studies will be needed to examine the effects of other anabolic agents and innovative forms of physical therapy. TRIAL REGISTRATION: ClinicalTrials.gov, NCT01270516. Registered 5 January 2011, https://clinicaltrials.gov/ct2/show/NCT01270516?term=Supinski&draw=2&rank=4

    Comprehensive and Holistic Analysis of HT-29 Colorectal Cancer Cells and Tumor-Bearing Nude Mouse Model: Interactions Among Fractions Derived From the Chinese Medicine Formula Tian Xian Liquid in Effects on Human Colorectal Carcinoma

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    The Chinese medicine formula Tian Xian Liquid (TXL) has been used clinically for cancer therapy in China for more than 25 years. However, the comprehensive and holistic effects of its bioactive fractions for various antitumor therapeutic effects have not been unraveled. This is the first study to scientifically elucidate the holistic effect of Chinese medicine formula for treating colon cancer, hence allowing a better understanding of the essence of Chinese medicine formula, through the comparison of the actions of TXL and its functional constituent fractions, including ethyl acetate (EA), butanol (BU), and aqueous (WA) fractions. Tissue-specific proliferative/antiproliferative effects of these fractions on human colorectal carcinoma HT-29 cells and splenocytes were studied by using the MTT assay. Their modulations on the expression of markers of antiproliferation, antimetastasis, reversion of multidrug resistance in treated HT-29 cells were examined with real-time polymerase chain reaction and Western blot analysis, and their modulations in a xenografted nude mouse model were examined by Western blot analysis. Results revealed that EA fraction slightly inhibited the proliferation of HT-29 cells, but tissue-specifically exerted the most potent antiproliferative effect on splenocytes. On the contrary, only TXL and BU fraction tissue-specifically contributed to the proliferation of splenocytes, but inhibited the proliferation of HT-29 cells. WA fraction exerted the most potent antiproliferative effect on HT-29 cells and also the strongest inhibitory action on tumor size in the nude mouse model in our previous study. In the HT-29 model, TXL and WA fraction exerted the most pronounced effect on upregulation of p21 mRNA and protein; TXL, and EA and WA fractions exerted the effect on downregulation of G1 phase cell cycle protein, cyclin D1 mRNA and protein; EA and BU fractions exerted the most prominent anti-invasive effect on anti-invasion via downregulation of MMP-1 mRNA; TXL potently reversed most multidrug resistance via downregulation of MDR-1 protein. In conclusion, the comprehensive and holistic effects of TXL were demonstrated with (a) mutual accentuation and mutual enhancement, (b) mutual counteraction and mutual suppression, and (c) mutual antagonism among the 3 constituent fractions. Moreover, the design of the present study may lead to further development of more tissue-specific effective drugs with minimal side effects for clinical use in combating carcinoma.published_or_final_versio

    Extracting information from vehicle exteriors via soil and insect DNA

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    © 2017 Elsevier. This manuscript version is made available under the CC-BY-NC-ND 4.0 license: http://creativecommons.org/licenses/by-nc-nd/4.0/ This author accepted manuscript is made available following 12 month embargo from date of publication (Oct 2017) in accordance with the publisher’s archiving policyDNA present on the surface of a vehicle provides evidence of past journeys which may be of forensic value. We show here the type of information that can be economically sourced by arbitrarily primed PCR and next generation sequencing of the DNA present in crushed insects and dust adhering to the upper surfaces and mud adhering to the underbody of a vehicle
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