34,436 research outputs found

    Democratic reform and health : interpreting causal estimates

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    In The Lancet Global Health, Hannah Pieters and colleagues (September, 2016)1 analyse the effect of democratic reforms on child mortality across the world. We wish to highlight, however, that even with sophisticated causal inference techniques, such results cannot necessarily be interpreted as causal effects. First, the results are compatible with a number of different theories including that democratic reforms have no effect on health ceteris paribus (ie, holding everything else fixed). Consider the cases of South Africa, Zambia, Mozambique, and Zimbabwe, all notably missing from the analyses but experiencing substantial democratic changes, analysed here using a similar synthetic control analysis (figure).1, 2 No change is observed in South Africa after the end of apartheid in 1994. In Zambia, after reform in 1991, a reduction is observed but not until the price of copper tripled and GDP per capita doubled. In Mozambique, the large fall is likely attributable to the cessation of the civil war in 1993. And in Zimbabwe, democratic restrictions in 1987 did not precipitate an increase in child mortality

    Can I have this dance? A perspective on the expectations and demands of current youth work practice in Scotland

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    This research principally discerns what young people want from their youth worker and portrays the significance of that relationship to them. The research illustrates young peoples’ thoughts and voice within the current discourse around what constitutes effective youth practice. It also reveals that communication, equity and respect which are at the top of young people’s agenda. The young people had reservations about certain types of youth work practice they had experienced in the past but valued and prioritised the personal characteristics of the youth worker

    The key ingredients of the electronic structure of FeSe

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    FeSe is a fascinating superconducting material at the frontier of research in condensed matter physics. Here we provide an overview on the current understanding of the electronic structure of FeSe, focusing in particular on its low energy electronic structure as determined from angular resolved photoemission spectroscopy, quantum oscillations and magnetotransport measurements of single crystal samples. We discuss the unique place of FeSe amongst iron-based superconductors, being a multi-band system exhibiting strong orbitally-dependent electronic correlations and unusually small Fermi surfaces, prone to different electronic instabilities. We pay particular attention to the evolution of the electronic structure which accompanies the tetragonal-orthorhombic structural distortion of the lattice around 90 K, which stabilizes a unique nematic electronic state. Finally, we discuss how the multi-band multi-orbital nematic electronic structure has an impact on the understanding of the superconductivity, and show that the tunability of the nematic state with chemical and physical pressure will help to disentangle the role of different competing interactions relevant for enhancing superconductivity.Comment: 21 pages, 11 figures, to appear in Annual Review of Condensed Matter Physic

    High-Speed Railway

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    Union Internationale des Chemins (UIC) defines the high-speed railway (HSR) as a high-speed railway system that contains the infrastructure and the rolling stock. The infrastructure can be newly built dedicated lines enabled for trains to travel with speed above 250 km/h or upgraded conventional lines with a speed up to 200 or even 220 km/h. HSR requires specially built trains with increased power to weight ratio and must have an in-cab signalling system as traditional signalling systems are incapable of above 200 km/h

    Sustainability and Related Factors of High Speed Railways

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    High-Speed Railways (HSR), which represent a safe and sustainable mode of transportation, provide access and mobility for the society, and support the growth of the economy in addition to creating new jobs, supporting welfare, and promoting local business activities. This research addresses the shortage of knowledge in evaluating the performance of selected HSR systems and in distinguishing the factors that contribute to the sustainable performance of HSRs. The aim of this study is to evaluate the sustainability of selected HSRs and identify factors that affect such sustainability. The objectives of this research are to evaluate productivity, technical and technological efficiency of the selected HSRs, define the factors that can affect productivity and efficiency scores and make suggestions for improving the sustainability of HSRs. The secondary data methodology has been used, supported by empirical evidence. Most of the data was gathered from the Internet, research in depth of the high-speed railways in the selected countries, and International Union of Railway’s websites in addition to analysing railway statistics and data from European and institutional publications. This includes the use of a multi-stage approach of applying three specialised software packages, namely, NVivo, DEA, and ISM SPSS. The main findings show that HSRs in Asia has higher productivity and higher efficiency scores than that of HSRs in Europe. The research found that the key factors among all the identified factors that affected the productivity and efficiency of HSRs are; density of population, average traction power of HSR trains, average time that passengers spend on trains and average distance that passengers travel on the HSR. The findings of this research can help develop strategic guidelines to improve the performance and, by the result, the sustainability of HSRs. The recommendations are drawn for more research expansion, including the consideration of other HSRs, particularly their best practices

    A radial mode ultrasonic horn for the inactivation of <i>Escherichia coli</i> K12

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    Tuned cylindrical radial mode ultrasonic horns offer advantages over ultrasonic probes in the design of flow-through devices for bacterial inactivation. This study presents a comparison of the effectiveness of a radial horn and probe in the inactivation of Escherichia coli K12. The radial horn is designed using finite element analysis and the predicted modal parameters are validated using experimental modal analysis. A validated finite element model of the probe is also presented. Visual studies of the cavitation fields produced by the radial horn and probe are carried out using luminol and also backlighting to demonstrate the advantages of radial horns in producing a more focused cavitation field with widely dispersed streamers. Microbiological studies show that, for the same power density, better inactivation of E. coli K12 is achieved using the radial horn and, also, the radial horn offers greater achievable power density resulting in further improvements in bacterial inactivation. The radial horn is shown to be more effective than the probe device and offers opportunities to design in-line flow-through devices for processing applications

    Blocking of word-boundary consonant lengthening in Sienese Italian

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    This paper examines an aspect of Raddoppiamento sintattico (RS), the lengthening of word-initial consonants following certain words e.g. tre [mm]ele ‘three apples’ in Italian. Most phonological accounts claim the phenomenon is predictable and obligatory (e.g. Nespor & Vogel 1986). However, descriptive sources on Italian (e.g. Camilli 1941) have long claimed that RS interacts with and can be blocked by other phenomena operative in natural speech e.g. pausing. In this paper we outline the phonetic details of the RS blocking phenomena and present the results of an auditory and preliminary acoustic analysis of the interaction between RS and these other phenomena based on a corpus of spontaneous speech data

    Analytic solutions of the magnetic annihilation and reconnection problems. I. Planar flow profiles

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    The phenomena of steady-state magnetic annihilation and reconnection in the vicinity of magnetic nulls are considered. It is shown that reconnective solutions can be derived by superposing the velocity and magnetic fields of simple magnetic annihilation models. These solutions contain most of the previous models for magnetic merging and reconnection, as well as introducing several new solutions. The various magnetic dissipation mechanisms are classified by examining the scaling of the Ohmic diffusion rate with plasma resistivity. Reconnection solutions generally allow more favorable "fast" dissipation scalings than annihilation models. In particular, reconnection models involving the advection of planar field components have the potential to satisfy the severe energy release requirements of the solar flare. The present paper is mainly concerned with magnetic fields embedded in strictly planar flows—a discussion of the more complicated three-dimensional flow patterns is presented in Part II [Phys. Plasmas 4, 110 (1997)]
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