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

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

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

Global Value Chains in Africa

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

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

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

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

The Scottish economy [September 1989]

[Abstract unavailable

The British economy [March 1989]

Evidence is mixed on whether growth in the economy is beginning to turn down. Nevertheless, the growth of GDP is forecast to fall from last year's high of 4.5% to 2.5% this year. Inflationary expectations are the most immediate cause for concern. But following the Budget there is concern that a relatively restrictive fiscal stance may bear down too heavily on output and employment during the next year