29,023 research outputs found

    The Desire for (Danish) Quality in High and Low Income Countries

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    We estimate the correlation between firm prices and sales within a CN8 product-country-year market. We do this for every market to which at least 16 different Danish firms exported between 1999 and 2006. Approximately 60% of Danish exports are to markets in which the price is negatively correlated with sales. These correlations are significantly different across destination countries within product categories, but across years for a given product-destination pair. While some existing theories perform better than others at predicting these patterns, none can reconcile the variation across countries. To fully explain the patterns, We introduce a model in which the price-sales correlation can be interpreted as the market's desire for high quality goods over low cost substitutes. We discover an inverted U shaped relation between a country's desire for quality and its per capita GDP, which we term a Quality Kuznets Curve. This curve has a turning point around 10 000 Euros for Danish exports. The Quality Kuznets Curve appears both when looking across products and within products.exports; firm heterogeneity; quality; productivity; Kuznets

    Demand Uncertainty: Exporting Delays and Exporting Failures

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    This paper presents a model of trade that explains why firms wait to export and why many exporters fail. Firms face uncertain demands that are only realized after the firm enters the destination. The model retools the timing of uncertainty resolution found in productivity heterogeneity models. This retooling addresses several shortcomings. First, the imperfect correlation of demands reconciles the sales variation observed in and across destinations. Second, since demands for the firm's output are correlated across destinations, a firm can use previously realized demands to forecast unknown demands in untested destinations. The option to forecast demands causes firms to delay exporting in order to gather more information about foreign demand. Third, since uncertainty is resolved after entry, many firms enter a destination and then exit after learning that they cannot profit. This prediction reconciles the high rate of exit seen in the first years of exporting. Finally, when faced with multiple countries in which to export, some firms will choose to sequentially export in order to slowly learn more about its chances for success in untested markets.firm heterogeneity; exporting; trade failures; trade delay

    Cost Linkages Transmit Volatility Across Markets

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    We present and test a model relating a firm's idiosyncratic cost, its exporting status, and the volatilities of its domestic and export sales. In prior models of trade, supply costs for domestic and exports were linear and thus additively separable. We introduce a nonlinear cost function in order to link the domestic and export supply costs. This theoretical contribution has two new implications for the exporting firm. First, the demand volatility in the foreign market now directly affects the firm's domestic sales volatility. Second, firms hedge domestic demand volatility with exports. The model has several testable predictions. First, larger firms have lower total and domestic sales volatilities. Second, foreign market volatility increases domestic sales volatilities for exporters. Third, exporters allocate output across both markets in order to reduce total sales volatility. We find evidence for these predictions with Danish firms operating between 1992 and 2006.

    Differential spatial modulation for high-rate transmission systems

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    This paper introduces a new differential spatial modulation (DSM) scheme which subsumes both the previously introduced DSM and high-rate spatial modulation (HR-SM) for wireless multiple input multiple output (MIMO) transmission. By combining the codeword design method of the HR-SM scheme with the encoding method of the DSM scheme, we develop a high-rate differential spatial modulation (HR-DSM) scheme equipped with an arbitrary number of transmit antennas that requires channel state information (CSI) neither at the transmitter nor at the receiver. The proposed approach can be applied to any equal energy signal constellations. The bit error rate (BER) performance of the proposed HR-DSM schemes is evaluated by using both theoretical upper bound and computer simulations. It is shown that for the same spectral efficiency and antenna configuration, the proposed HR-DSM outperforms the DSM in terms of bit error rate (BER) performance

    18F-FDG PET/CT Imaging of the Pancreas: Spectrum of Diseases

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    Since the introduction of integrated positron emission tomography-computed tomography (PET/CT), it has a great impact on the field of oncology. Comparing to other conventional scanners, only PET/CT is capable of providing important information on accurate detecting, staging/restaging, and post-therapeutic monitoring of many cancers. Many studies have demonstrated that PET/CT changes the management in approximately 30% of all cancer patients. Because 2-(18F)-fluoro-2-deoxy-D-glucose (FDG) is a nonspecific tracer, understanding the PET/CT limitations and pitfalls for various pancreatic conditions can lead to more accurate interpretation of PET/CT images, which ultimately would impact patient care. As a result, it is important for radiologists and other clinicians to familiarize themselves with a wide spectrum of pancreatic PET/CT findings simulating cancer from benign entities

    Isogeometric analysis for functionally graded microplates based on modified couple stress theory

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    Analysis of static bending, free vibration and buckling behaviours of functionally graded microplates is investigated in this study. The main idea is to use the isogeometric analysis in associated with novel four-variable refined plate theory and quasi-3D theory. More importantly, the modified couple stress theory with only one material length scale parameter is employed to effectively capture the size-dependent effects within the microplates. Meanwhile, the quasi-3D theory which is constructed from a novel seventh-order shear deformation refined plate theory with four unknowns is able to consider both shear deformations and thickness stretching effect without requiring shear correction factors. The NURBS-based isogeometric analysis is integrated to exactly describe the geometry and approximately calculate the unknown fields with higher-order derivative and continuity requirements. The convergence and verification show the validity and efficiency of this proposed computational approach in comparison with those existing in the literature. It is further applied to study the static bending, free vibration and buckling responses of rectangular and circular functionally graded microplates with various types of boundary conditions. A number of investigations are also conducted to illustrate the effects of the material length scale, material index, and length-to-thickness ratios on the responses of the microplates.Comment: 57 pages, 14 figures, 18 table

    Hidden Markov Model Identifiability via Tensors

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    The prevalence of hidden Markov models (HMMs) in various applications of statistical signal processing and communications is a testament to the power and flexibility of the model. In this paper, we link the identifiability problem with tensor decomposition, in particular, the Canonical Polyadic decomposition. Using recent results in deriving uniqueness conditions for tensor decomposition, we are able to provide a necessary and sufficient condition for the identification of the parameters of discrete time finite alphabet HMMs. This result resolves a long standing open problem regarding the derivation of a necessary and sufficient condition for uniquely identifying an HMM. We then further extend recent preliminary work on the identification of HMMs with multiple observers by deriving necessary and sufficient conditions for identifiability in this setting.Comment: Accepted to ISIT 2013. 5 pages, no figure

    Appropriate use of endoscopy in the diagnosis and treatment of gastrointestinal diseases: up-to-date indications for primary care providers

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    The field of endoscopy has revolutionized the diagnosis and treatment of gastrointestinal (GI) diseases in recent years. Besides the ‘traditional’ endoscopic procedures (esophagogastroduodenoscopy, colonoscopy, flexible sigmoidoscopy, and endoscopic retrograde cholangiopancreatography), advances in imaging technology (endoscopic ultrasonography, wireless capsule endoscopy, and double balloon enteroscopy) have allowed GI specialists to detect and manage disorders throughout the digestive system. This article reviews various endoscopic procedures and provides up-to-date endoscopic indications based on the recommendations of American Society for Gastrointestinal Endoscopy and American Cancer Society for primary care providers in order to achieve high-quality and cost-effective care

    Women Surrealist Photographers and Their Response to the Objectification of Women in Male Surrealist Art

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    Objectification of women in Male Surrealist art depicted the male gaze in its darkest form, through the ideas of the uncanny, fetish, and convulsive beauty. Women were treated as objects throughout Surrealist photography and painting instead of as human subjects. Their femininity and beauty were valued to the extent of held belief that a woman’s destiny is to be beautiful and be present for the male gaze. Women Surrealists have gained notoriety in the last sixty years for their presence in the Surrealist movement and for their diligence in providing the female perspective in opposition to the male perspective. This study observes the photographic works of the Women Surrealists, Claude Cahun and Francesca Woodman, and their method of response to the objectification of women while also examining the political context of Claude Cahun’s involvement in the Surrealist movement and the influence of Andre Breton, Claude Cahun and other early surrealist artists on late surrealist artist Francesca Woodman. Photographs, surrealist texts, and journal entries are used as primary sources to approach and reason why these two artists chose the medium of photography as their method response, and how objectification, photography, and the self-portrait incited the modern artist-as-subject trend through Claude Cahun and Francesca Woodman.https://scholarscompass.vcu.edu/uresposters/1154/thumbnail.jp

    Minimum fuel rocket maneuvers in horizontal flight.

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76185/1/AIAA-6726-616.pd
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