276 research outputs found

    An investigation of the association between toxin producing staphylococcus, biochemical changes and jaw muscle pain.

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    Objectives: To assess the expression of the symptoms of jaw muscle pain and its association with alterations in biochemistry, other symptoms and the carriage of staphylococci. Methods: Three different study populations were assessed. The first was selected and examined by the author and consisted of 43 pain and 41 age and sex matched controls. The second was a study of CFS patients who were blinded to the author and the author subsequently examined the associations between jaw muscle symptom reporting and the standardised biochemistry measures. The third study was also blinded to the author but included an investigation of staphylococci and certain cytokine and biochemistry measures. Results: The three studies clearly establish an association between the carriage of toxicogenic coagulase negative staphylococci and the expression of jaw muscle pain in both males and females. These associations were homogeneous and were found whether the patients were selected on the basis of having jaw muscle pain or selected from within a population of patients selected on the basis of having Chronic Fatigue Syndrome. The studies associated the changes with variations in biochemistry and these were in turn associated with symptom expression within the jaw muscle pain patients. These biochemical alterations included the dysregulation of immune cell counts, cytokines, electrolyte and protein metabolism. These symptoms and biochemical changes were associated with pain severity and illness duration and staphylococcal toxin production. From the data a model was developed which shows the mechanisms involved in the development of chronic pain in the jaw muscles. Conclusions: The carriage of toxicogenic coagulase-negative staphylococci were found to be associated with the expression of jaw muscle pain and the alterations in biochemistry associated with these symptoms

    Characterizing growth instability: new evidence on unit roots and structural breaks in countries’ long run trajectories

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    In this paper we investigate whether long run time series of income per capita are better described by a trend-stationary model with few structural changes or by unit root processes in which permanent stochastic shocks are responsible for the observed growth discontinuities. For a group of advanced and developing countries in the Maddison database, we employ a unit root test that allows for an unspecified number of breaks under the alternative hypothesis (up to some ex ante determined maximum). Monte Carlo simulations studying the finite sample properties of the test are reported and discussed. When compared with previous findings in the literature, our results show less evidence against the unit root hypothesis. We find even fewer rejections when relaxing the assumption of Gaussian shocks. Our results are broadly consistent with the implications of evolutionary macro models which posit frequent growth shifts and fat-tailed distribution of aggregate shocks

    Unraveling wage inequality: tangible and intangible assets, globalization and labor market regulations

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    In this paper, we study the asymmetric effects of different types of capital-embodied technological change, as proxied by tangible and intangible assets, on relative wages (high- to medium-skilled, high- to low-skilled and medium- to low-skilled workers), relying upon the technology-skill complementarity and polarization of the labor force frameworks. We also consider two additional major channels that contribute to shaping wage differentials: globalization (in terms of trade openness and global value chains participation) and labor market institutions. The empirical analysis is carried out using a panel dataset comprising 17 mostly advanced European economies and 5 industries, with annual observations spanning the period 2008-2017. Our findings suggest that software and databases-as a proxy for intangible technologies-exert downward pressure on low-skilled wages, while robotics is associated with a polarization of the wage distribution at the expense of middle-skilled labor. Additionally, less-skilled workers' relative wages are negatively affected by trade openness and global value chain participation, but positively influenced by sector-specific labor market regulations

    Global Value Chains in Africa

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    This paper provides evidence on the extent of Global Value Chain (GVC) participation by Africa as a region and for individual African countries. We find that Africa as a whole is heavily involved in GVCs, being more engaged in GVCs than many developing country regions as well as developed countries such as the USA. This overall finding hides the fact that much of Africa's participation in GVCs is in upstream production, with African firms providing primary inputs to firms in countries further down the value chain. The possibility of upgrading within GVCs in Africa is likely to be limited therefore, something which the current analysis suggests. Despite this, we observe a great deal of heterogeneity in terms of GVC participation and upgrading across African countries, with a number of African countries participating in GVCs to a relatively large extent. (authors' abstract

    Determining position and orientation of a 3-wheel robot on a pipe using an accelerometer

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    Accurate positioning of robots on pipes is a challenge in automated industrial inspection. It is typically achieved using expensive and cumbersome external measurement equipment. This paper presents an Inverse Model method for determining the orientation angle (α ) and circumferential position angle (ω) of a 3 point of contact robot on a pipe where measurements are taken from a 3-axis accelerometer sensor. The advantage of this system is that it provides absolute positional measurements using only a robot mounted sensor. Two methods are presented which follow an analytical approximation to correct the estimated values. First, a correction factor found though a parametric study between the robot geometry and a given pipe radius, followed by an optimization solution which calculates the desired angles based on the system configuration, robot geometry and the output of a 3-axis accelerometer. The method is experimentally validated using photogrammetry measurements from a Vicon T160 positioning system to record the position of a three point of contact test rig in relation to a test pipe in a global reference frame. An accelerometer is attached to the 3 point of contact test rig which is placed at different orientation (α ) and circumferential position (ω) angles. This work uses a new method of processing data from an accelerometer sensor to obtain the α and ω angles. The experimental results show a maximum error of 3.40° in α and 4.17° in ω , where the ω circumferential positional error corresponds to ±18mm for the test pipe radius of 253mm

    Bootstrapping Conversational Agents With Weak Supervision

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    Many conversational agents in the market today follow a standard bot development framework which requires training intent classifiers to recognize user input. The need to create a proper set of training examples is often the bottleneck in the development process. In many occasions agent developers have access to historical chat logs that can provide a good quantity as well as coverage of training examples. However, the cost of labeling them with tens to hundreds of intents often prohibits taking full advantage of these chat logs. In this paper, we present a framework called \textit{search, label, and propagate} (SLP) for bootstrapping intents from existing chat logs using weak supervision. The framework reduces hours to days of labeling effort down to minutes of work by using a search engine to find examples, then relies on a data programming approach to automatically expand the labels. We report on a user study that shows positive user feedback for this new approach to build conversational agents, and demonstrates the effectiveness of using data programming for auto-labeling. While the system is developed for training conversational agents, the framework has broader application in significantly reducing labeling effort for training text classifiers.Comment: 6 pages, 3 figures, 1 table, Accepted for publication in IAAI 201

    Productive efficiency, structural change, and catch-up within Africa

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    This paper studies the dynamics of labor productivity convergence and technology catch-up within Africa, shedding light on two important and inter-related issues that are central to Africa’s growth: (i) convergence of relative productivity among African countries and (ii) the role of technological change and technological catch-up in driving productivity change across and within African countries. We do this by using a nonparametric method to estimate an African production frontier. Productivity change in Africa is decomposed into two components: technological change and technological catch-up. Our results show that Botswana and Mauritius are the only two countries in Africa that have converged to the productivity as well as the efficiency level of the frontier. This successful convergence is driven more by technological catch-up and less by technological change. We explore the special role of technological catch-up by decomposing it into within-sector convergence, between-sector convergence and initial specialization using a structural model (Shift and Share catch-up decomposition). The results highlight the special role of structural change in closing the productivity gap with the frontier. This paper contributes to recent evidence suggesting that countries can climb up the income ladder at a faster rate through a two-pronged transformation – i.e., structural change and technological catch-up
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