The impact of mobile telephony on developing country micro-enterprises: a Nigerian case study

Informational challenges-absence, uncertainty, asymmetry-shape the working of markets and commerce in many developing countries. For developing country micro-enterprises, which form the bulk of all enterprises worldwide, these challenges shape the characteristics of their supply chains. They reduce the chances that business and trade will emerge. They keep supply chains localised and intermediated. They make trade within those supply chains slow, costly, and risky. Mobile telephony may provide an opportunity to address the informational challenges and, hence, to alter the characteristics of trade within micro-enterprise supply chains. However, mobile telephony has only recently penetrated. This paper, therefore, presents one of the first case studies of the impact of mobile telephony on the numerically-dominant form of enterprise, based around a case study of the cloth-weaving sector in Nigeria. It finds that there are ways in which costs and risks are being reduced and time is saved, often by substitution of journeys. But it also finds a continuing need for journeys and physical meetings due to issues of trust, design intensity, physical inspection and exchange, and interaction complexity. As a result, there are few signs of the de-localisation or disintermediation predicted by some commentators. An economising effect of mobile phones on supply chain processes may therefore co-exist with the entrenchment of supply chain structures and a growing 'competitive divide' between those with and without access to telephony

M.A.R.S.: The momentum spectrum of muons to 800 GeVc in the vertical direction

The sea-level vertical muon differential momentum spectrum has been measured using the Durham spectrograph MARS in the region 20 GeV/c to 500 GeV/c. The instrumental biases have been studied in detail and allowances made for the particle detector inefficiencies to render to measurement absolute. A simple muon production and propagation model has been used to predict the pion and kaon production spectra from the muon spectrum measurements. It has been found impossible to fit, with any degree of significance, a constant exponent power law pion and kaon production spectrum, having a reasonable value of the K/π ratio (0.15). A better fit is obtained if the exponent is allowed to increase with momentum, and in particular a model with two values of the exponent has been fitted. The muon spectrum has been extrapolated both above and below 500 GeV/c and 20 CeV/c respectively, and at low momenta good agreement is found with the recent "form fit" of De et al. (1972). The present results are compared with previous and contempary measurements of the muon spectrum with the conclusion that there is no evidence, from other recent measurements, that they are incorrect. Comparison with surveys of indirect measurements at higher energies however suggest that the muon spectrum cannot continue in this enhanced fashion much beyond 1000 GeV. Finally an absolute integral rate experiment has been performed using MARS as a range spectrograph, and the intensity above 7.12 GeV/c is found to be in agreement with a previous similar measurement made with the instrument. Further it is concluded that the intensity at this momentum is in agreement with the extrapolation of the differential spectrum measurements below 20 GeV/c

Image processing techniques in nuclear medicine

The application of image processing techniques to radionuclide images acquired on a gamma camera - computer system has been investigated. Hepatic perfusion imaging studies with 99Tcm-tin colloid were performed in patients with primary colorectal carcimma. The hepatic perfusion index performed poorly in the detection of those patients with occult or overt hepatic metastastes, as did mean transit times of liver colloid flow derived from deconvolution analysis. A discriminant function was developed which separated those patients with occult metastases from those without liver disease. A fully automatic algorithm to derive a left ventricular edge from each frame of an ECG gated cardiac blood pool study was developed and validated in patient studies. Left ventricular ejection fractions calculated from count rates within the edge were reproducible and correlated well with ejection fractions derived from the same images by a manual technique, and with ejection fractions derived from left ventricular cineangiography. Studies were performed in patients to evaluate the effectiveness of tomographic imaging of the myocardial perfusion imaging agent 99Tcm-tBIN for detection of ischaemic heart disease. Tomographic reconstructions in the planes of the axes of the left ventricle gave better results than transaxial reconstructions or planar imaging. Choice of the optimum reconstruction filter for use in tomography using 99Tcm-tBIN was examined by means of patient am phantom studies. These showed that more accurate diagnoses and better reconstructions were obtained with smoothing filters than by the use of sharp reconstruction filters. This work shows that optimum image processing techniques must be established to attain the best possible results with new radiopharmaceuticals for nuclear medicine investigations

Cultural political economy and urban heritage tourism

The paper explains a cultural political economy “framing” for interpreting heritage tourism in urban contexts. Key ideas behind this research perspective are explained and illustrated through discussion of past research studies of urban heritage tourism. It is underpinned by a relational view of the inter-connectedness of societal relations, and an emphasis on taking seriously both the cultural/semiotic and the economic/political in the co-constitution of urban heritage tourism’s social practices and features. A case study of heritage tourism in Nanjing, China considers cultural political economy’s relevance and value, including the distinctive research questions it raises. It reveals, for example, how economic relations in the built environment were related to tourist meaning-making and identities in the cultural/semiotic sphere

The BRACElet 2009.1 (Wellington) Specification

BRACElet is a multi-institutional computer education research study of novice programmers. The project is open to new members. The purpose of this paper is to: (1) provide potential new members with an overview of BRACElet, and (2) specify the common core for the next data collection cycle. In this paper, BRACElet is taking the unusual step of making its study design public before data is collected. We invite anyone to run their own study using our study design, and publish their findings, irrespective of whether they formally join BRACElet. We look forward to reading their paper. © 2009, Australian Computer Society, Inc

LHAPDF : PDF Use from the Tevatron to the LHC

Parton Density Functions (PDFs) and their uncertainties are extremely important topics for both the Tevatron and the LHC. Experiments at the Tevatron can enhance this knowledge not only by constraining the PDF fits, but also by developing and refining the available PDF tools through feed-back from the experiments that are currently analyzing the highest energy hadron collider data available. It is important that the community has standardized tools and methods at its disposal. In this note we summarize briefly the most recent developments of the The Les Houches Accord PDF (LHAPDF), which is the modern replacement for PDFLIB. We also outline and compare the methods of quantifying the impact of PDF uncertainties on physical observables. The PDF weighting method for propagating errors from PDFs to event generator observables is outlined in detail, and example code for using this method with PYTHIA is also included

The CEDAR Project

We describe the plans and objectives of the CEDAR project (Combined e-Science Data Analysis Resource for High Energy Physics) newly funded by the PPARC e-Science programme in the UK. CEDAR will combine the strengths of the well established and widely used HEPDATA database of HEP data and the innovative JetWeb data/Monte Carlo comparison facility, built on the HZTOOL package, and will exploit developing grid technology. The current status and future plans of both of these individual sub-projects within the CEDAR framework are described, showing how they will cohesively provide (a) an extensive archive of Reaction Data, (b) validation and tuning of Monte Carlo programs against these reaction data sets, and (c) a validated code repository for a wide range of HEP code such as parton distribution functions and other calculation codes used by particle physicists. Once established it is envisaged CEDAR will become an important Grid tool used by LHC experimentalists in their analyses and may well serve as a model in other branches of science where there is a need to compare data and complex simulations.Comment: 4 pages, 4 postscript figures, uses CHEP2004.cls. Presented at Computing in High-Energy Physics (CHEP'04), Interlaken, Switzerland, 27th September - 1st October 200

HepForge: A lightweight development environment for HEP software

Setting up the infrastructure to manage a software project can become a task as significant writing the software itself. A variety of useful open source tools are available, such as Web-based viewers for version control systems, "wikis" for collaborative discussions and bug-tracking systems, but their use in high-energy physics, outside large collaborations, is insubstantial. Understandably, physicists would rather do physics than configure project management tools. We introduce the CEDAR HepForge system, which provides a lightweight development environment for HEP software. Services available as part of HepForge include the above-mentioned tools as well as mailing lists, shell accounts, archiving of releases and low-maintenance Web space. HepForge also exists to promote best-practice software development methods and to provide a central repository for re-usable HEP software and phenomenology codes.Comment: 3 pages, 0 figures. To be published in proceedings of CHEP06. Refers to the HepForge facility at http://hepforge.cedar.ac.u