An analysis of progressive addition spectacles lens design by the use of interferometry

Progressive addition spectacle lenses (PALs) have now become the method of choice for many presbyopic individuals to alleviate the visual problems of middle-age. Such lenses are difficult to assess and characterise because of their lack of discrete geographical locators of their key features. A review of the literature (mostly patents) describing the different designs of these lenses indicates the range of approaches to solving the visual problem of presbyopia. However, very little is published about the comparative optical performance of these lenses. A method is described here based on interferometry for the assessment of PALs, with a comparison of measurements made on an automatic focimeter. The relative merits of these techniques are discussed. Although the measurements are comparable, it is considered that the interferometry method is more readily automated, and would be ultimately capable of producing a more rapid result.

Physical and psychophysical analysis of progressive addition lens embodiments

The extent to which the surface parameters of Progressive Addition Lenses (PALs) affect successful patient tolerance was investigated. Several optico-physical evaluation techniques were employed, including a newly constructed surface reflection device which was shown to be of value for assessing semi-finished PAL blanks. Detailed physical analysis was undertaken using a computer-controlled focimeter and from these data, iso-cylindrical and mean spherical plots were produced for each PAL studied. Base curve power was shown to have little impact upon the distribution of PAL astigmatism. A power increase in reading addition primarily caused a lengthening and narrowing of the lens progression channel. Empirical measurements also indicated a marginal steepening of the progression power gradient with an increase in reading addition power. A sample of the PAL wearing population were studied using patient records and questionnaire analysis (90% were returned). This subjective analysis revealed the reading portion to be the most troublesome lens zone and showed that patients with high astigmatism (> 2.00D) adapt more readily to PALs than those with spherical or low cylindrical (2.00D) corrections. The psychophysical features of PALs were then investigated. Both grafting visual acuity (VA) and contrast sensitivity (CS) were shown to be reduced with an increase in eccentricity from the central umbilical line. Two sample populations (N= 20) of successful and unsuccessful PAL wearers were assessed for differences in their visual performance and their adaptation to optically induced distortion. The possibility of dispensing errors being the cause of poor patient tolerance amongst the unsuccessful wearer group was investigated and discounted. The contrast sensitivity of the successful group was significantly greater than that of the unsuccessful group. No differences in adaptation to or detection of curvature distortion were evinced between these presbyopic groups.

Progressive structural analysis for dynamic recognition of on-line handwritten mathematical expressions

Structural analysis in handwritten mathematical expressions focuses on interpreting the recognized symbols using geometrical information such as relative sizes and positions of the symbols. Most existing approaches rely on hand-crafted grammar rules to identify semantic relationships among the recognized mathematical symbols. They could easily fail when writing errors occurred. Moreover, they assume the availability of the whole mathematical expression before being able to analyze the semantic information of the expression. To tackle these problems, we propose a progressive structural analysis (PSA) approach for dynamic recognition of handwritten mathematical expressions. The proposed PSA approach is able to provide analysis result immediately after each written input symbol. This has an advantage that users are able to detect any recognition errors immediately and correct only the mis-recognized symbols rather than the whole expression. Experiments conducted on 57 most commonly used mathematical expressions have shown that the PSA approach is able to achieve very good performance results.

Towards a web-based progressive handwriting recognition environment for mathematical problem solving

The emergence of pen-based mobile devices such as PDAs and tablet PCs provides a new way to input mathematical expressions to computer by using handwriting which is much more natural and efficient for entering mathematics. This paper proposes a web-based handwriting mathematics system, called WebMath, for supporting mathematical problem solving. The proposed WebMath system is based on client-server architecture. It comprises four major components: a standard web server, handwriting mathematical expression editor, computation engine and web browser with Ajax-based communicator. The handwriting mathematical expression editor adopts a progressive recognition approach for dynamic recognition of handwritten mathematical expressions. The computation engine supports mathematical functions such as algebraic simplification and factorization, and integration and differentiation. The web browser provides a user-friendly interface for accessing the system using advanced Ajax-based communication. In this paper, we describe the different components of the WebMath system and its performance analysis.

Spatial patterns of the tau pathology in progressive supranuclear palsy

Progressive supranuclear palsy (PSP) is characterized neuropathologically by neuronal loss, gliosis, and the presence of tau-immunoreactive neuronal and glial cell inclusions affecting subcortical and some cortical regions. The objectives of this study were to determine (1) the spatial patterns of the tau-immunoreactive pathology, viz., neurofibrillary tangles (NFT), oligodendroglial inclusions (GI), tufted astrocytes (TA), and Alzheimer's disease-type neuritic plaques (NP) in PSP and (2) to investigate the spatial correlations between the histological features. Post-mortem material of cortical and subcortical regions of eight PSP cases was studied. Spatial pattern analysis was applied to the NFT, GI, TA, NP, abnormally enlarged neurons (EN), surviving neurons, and glial cells. NFT, GI, and TA were distributed either at random or in regularly distributed clusters. The EN and NP were mainly randomly distributed. Clustering of NFT and EN was more frequent in the cortex and subcortical regions, respectively. Variations in NFT density were not spatially correlated with the densities of either GI or TA, but were positively correlated with the densities of EN and surviving neurons in some regions. (1) NFT were the most widespread tau-immunoreactive pathology in PSP being distributed randomly in subcortical regions and in regular clusters in cortical regions, (2) GI and TA were more localized and exhibited a regular pattern of clustering in subcortical regions, and (3) neuronal and glial cell pathologies were not spatially correlated. © 2012 Springer-Verlag.

Inequality, democracy and taxation:lessons from the post-Communist transition

Using data for the period 1989 – 2002, we examine the determinants of income inequality in post-communist economies. We find a strong positive association between equality and tax collection but note that this relationship is significantly stronger under authoritarian regimes than under democracies. We also discover that countries introducing sustainable democratic institutions early are characterised by lower inequality. We also confirm that education fosters equality and find that larger countries are prone to higher levels of inequality.

White matter pathology in progressive supranuclear palsy (PSP):a quantitative study of 8 cases

Aims: To quantify white matterpathology in progressive supranuclear palsy (PSP). Material: Histological sections of white matter of 8 PSP and 8 control cases \Method: Densities and spatial patterns of vacuolation, glial cell nuclei, and glial inclusions (GI) were measured in 8cortical and subcortical fiber tracts. Results: No GI wereobserved in control fiber tracts. Densities of vacuoles and glial cell nuclei were greater in PSP than in controls. In PSP, density of vacuoles was greatest in the alveus, frontopontine fibers (FPF), and central tegmental tract (CTT), and densities of glial cell nuclei were greater in cortical than subcortical regions.The highest densities of GI were observed in the basal ganglia, FPF, cerebellum, andsuperior frontal gyrus (SFG). Vacuoles, glialcells and GI were distributed randomly, uniformly,in regularly distributed clusters, or in large clusters across fiber tracts. GI wermore frequently distributed in regular clusters than the vacuoles and glial cell nuclei.Vacuoles, glial cell nuclei, and GI were not spatially correlated. Conclusions: The data suggest significant degeneration of white matter in PSP, vacuolation being related to neuronal loss in adjacent gray matterregions,GI the result of abnormal tau released from damaged axons, and gliosis a responseto these changes. © 2013.

The prevalence and phenotype of activated microglia/macrophages within the spinal cord of the hyperostotic mouse (twy/twy) changes in response to chronic progressive spinalcord compression:implications for human cervical compressive myelopathy

Background:Cervical compressive myelopathy, e.g. due to spondylosis or ossification of the posterior longitudinal ligament is a common cause of spinal cord dysfunction. Although human pathological studies have reported neuronal loss and demyelination in the chronically compressed spinal cord, little is known about the mechanisms involved. In particular, the neuroinflammatory processes that are thought to underlie the condition are poorly understood. The present study assessed the localized prevalence of activated M1 and M2 microglia/macrophages in twy/twy mice that develop spontaneous cervical spinal cord compression, as a model of human disease.Methods:Inflammatory cells and cytokines were assessed in compressed lesions of the spinal cords in 12-, 18- and 24-weeks old twy/twy mice by immunohistochemical, immunoblot and flow cytometric analysis. Computed tomography and standard histology confirmed a progressive spinal cord compression through the spontaneously development of an impinging calcified mass.Results:The prevalence of CD11b-positive cells, in the compressed spinal cord increased over time with a concurrent decrease in neurons. The CD11b-positive cell population was initially formed of arginase-1- and CD206-positive M2 microglia/macrophages, which later shifted towards iNOS- and CD16/32-positive M1 microglia/macrophages. There was a transient increase in levels of T helper 2 (Th2) cytokines at 18 weeks, whereas levels of Th1 cytokines as well as brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF) and macrophage antigen (Mac) -2 progressively increased.Conclusions:Spinal cord compression was associated with a temporal M2 microglia/macrophage response, which may act as a possible repair or neuroprotective mechanism. However, the persistence of the neural insult also associated with persistent expression of Th1 cytokines and increased prevalence of activated M1 microglia/macrophages, which may lead to neuronal loss and demyelination despite the presence of neurotrophic factors. This understanding of the aetiopathology of chronic spinal cord compression is of importance in the development of new treatment targets in human disease. © 2013 Hirai et al.

Bend and index insensitive long period grating in progressive three layered optical fibre

A long period fibre grating written in progressive three layered optical fibre was examined. The bending sensitivity of the optical fibre was measured. It was found that the fibre shows an attenuation band that has a very low bending sensitivity compared to normal step-index fibres.

Taxation of intellectual property: the new regime for companies

Central aspects of new regime for taxation of intangible assets introduced by FA 2002 which seeks to align tax treatment with accounting treatment of intellectual property

Corporate taxation, corporate power, and corporate harm

Globalisation has increased corporate tax competition amongst states and facilitated widespread corporate tax avoidance. Some of the largest businesses now pay little or no tax: in some cases with the active assistance of governments. This article examines contemporary corporation tax policies, outlines some of the key methods corporations use to minimise their tax liabilities, explores the interdependencies between the demand for reduced tax liabilities and the professional infrastructure of tax planning and avoidance, and examines how the contemporary political economy of corporate taxation enhances the bargaining power of transnational corporations in the implementation of tax policy.

Essentials of Jamaican taxation

This fourth edition of Essentials of Jamaican Taxation as with earlier editions covers the material for an undergraduate course in Jamaican taxation and deals with the theory of taxation and its application through the main provisions of the Income Tax Act, the various Acts governing payroll taxes, the General Consumption Tax Act and the Contractors Levy Act. This edition covers changes which took place after 2007 including the main provisions in the 2012 budget. The text is designed to give mainly students of accounting a working knowledge of taxation as it is administered in Jamaica so they are equipped to perform computations of tax payable by businesses/employers, employees, self-employed, and persons with income from sources other than employment. Most of the text should be understood quite readily by readers other than students who wish to be informed on taxation matters.

Impacts of energy taxation in the enlarged European Union, evaluation with GEM-E3 Europe

The objective of this study is twofold: first to analyze how the implementation of the EU energy tax policies will affect the EU and its Member States and secondly to analyze how energy tax policies can contribute to climate policy objectives in the enlarged EU.

Adósság, pénz és szabadság = Taxation, money and freedom

A tanulmány a Déltengeri Társasággal foglalkozó tanulmány folytatása (Madarász [2011]). A 18. századi brit államadósság szerepéről és kezeléséről szóló modern gazdaságtörténeti értékelések áttekintése után a tanulmány részletesen bemutatja Davenant, Defoe, Bolingbroke, Hume, Wallace, Pinto, Steuart és Smith érvelését a \"közhitel\" lehetséges és szükségszerű gazdasági és politikai hatásairól, a háborús kiadások fedezésének módjairól. Részletesebben tárgyalja Hume és Smith álláspontját a papírpénz és a bankok szerepéről, a pénzmennyiség változásának következményeiről és a skóciai \"szabad\" bankrendszer jellemzőiről. A vita egyik oldalán a közhitelt szükséges, ám veszélyes eszköznek tekintették, amely válságba sodorhatja az országot, és aláássa a politikai szabadságot, a másik vélemény szerint a kereskedő állam adóssága szükséges és előnyös, ösztönzi a gazdaság fejlődését, és kifejezi a polgárok bizalmát a kormányzat iránt. / === / The study, following on from the author s previous work on the history of South Sea Company, focuses on the issue of public debt in 18th-century British economic writings. The first part reviews recent debates among economic historians: how to explain the growing credibility of British governments after 1689. The next details the arguments of some important protagonists in the early modern age - Davenant, Defoe, Bolingbroke, Hume, Wallace, Pinto, Steuart and Smith - on the expected economic and political consequences of an increasing public debt and on the methods of financing wars. This is followed by discussion of the monetary theories of Hume and Smith, notably their views on banks, credit, paper money, the effects of increasing money supply, and the features of free\" Scottish banking system. Two main lines of argument were advanced in the controversies on public debt. Several writers regarded it as a necessary but dangerous instrument that undermines political liberty and can lead the state into financial bankruptcy. Others described it as not only necessary, but advantageous to a commercial nation, by stimulating trade and development and symbolizing the public s confidence in their government.