Remote sensing applied to slope stability in mountainous roads in Iran

The Alborz Mountain range separates the northern part of Iran from the southern part. It also isolates a narrow coastal strip to the south of the Caspian Sea from the Central Iran plateau. Communication between the south and north until the 1950's was via two roads and one rail link. In 1963 work was completed on a major access road via the Haraz Valley (the most physically hostile area in the region). From the beginning the road was plagued by accidents resulting from unstable slopes on either side of the valley. Heavy casualties persuaded the government to undertake major engineering works to eliminate ''black spots" and make the road safe. However, despite substantial and prolonged expenditure the problems were not solved and casualties increased steadily due to the increase in traffic using the road. Another road was built to bypass the Haraz road and opened to traffic in 1983. But closure of the Haraz road was still impossible because of the growth of settlements along the route and the need for access to other installations such as the Lar Dam. The aim of this research was to explore the possibility of applying Landsat MSS imagery to locating black spots along the road and the instability problems. Landsat data had not previously been applied to highway engineering problems in the study area. Aerial photographs are better in general than satellite images for detailed mapping, but Landsat images are superior for reconnaissance and adequate for mapping at the 1 :250,000 scale. The broad overview and lack of distortion in the Landsat imagery make the images ideal for structural interpretation. The results of Landsat digital image analysis showed that certain rock types and structural features can be delineated and mapped. The most unstable areas comprising steep slopes, free of vegetation cover can be identified using image processing techniques. Structural lineaments revealed from the image analysis led to improved results (delineation of unstable features). Damavand Quaternary volcanics were found to be the dominant rock type along a 40 km stretch of the road. These rock types are inherently unstable and partly responsible for the difficulties along the road. For more detailed geological and morphological interpretation a sample of small subscenes was selected and analysed. A special developed image analysis package was designed at Aston for use on a non specialized computing system. Using this package a new and unique method for image classification was developed, allowing accurate delineation of the critical features of the study area.

Rural road accidents in Iran: analysis, comparison and the cost

In the general introduction of the road-accident phenomenon inside and outside Iran, the results of previous research-works and international conferences and seminars on road-safety have been reviewed. Also a sample-road between Tehran and Mashad has been investigated as a case-study. Examining the road-accident data and iriformation,first: the information presented in road-accident report-forms in developed countries is discussed and, second: the procedures for road-accident data collection in Iran are investigated in detail. The data supplied by Iran Road-Police Central Statistics Office, is analysed, different rates are computed, due comparisons with other nations are made, and the results are discussed. Also such analysis and comparisons are presented for different provinces of Iran. It is concluded that each province with its own natural, geographical, social and economical characteristics possesses its own reasons for the quality and quantity of road-accidents and therefore must receive its own appropriate remedial solutions. The question~ of "what is the cost of road-accidents", "why and how evaluate the cost", "what is the appropriate way of approach to such evaluation" are all discussed and then "the cost of road-accidents in Iran" based on two different approaches: "Gross National Output"and "court award" is computed. It is concluded that this cost is about 1.5 per cent of the country's national product. In Appendix 3 an impressive example is given of the trend of costs and benefits that can be attributed to investment in road-safety measures.

Public and private hospital services reform:an investigation in Iranian hospitals

This research aimed to present a model of efficiency for selected public and private hospitals of East Azerbaijani province of Iran by making use of DEA approach in order to recognize and suggest the best practice standards. In other words, its aim was to suggest a suitable context to develop efficient hospital systems while maintaining the quality of care at minimum expenditures. It is recommended for inefficient hospitals to make use of the followings: transferring, selling, or renting idle/unused beds; transferring excess doctors and nurses to the efficient hospitals or other health centers; pensioning off, early retirement clinic officers, technicians/technologists, and other technical staff. The saving obtained from the above approaches could be used to improve remuneration for remaining staff and quality of health care services of hospitals, rural and urban health centers, support communities to start or sustain systematic risk and resource pooling and cost sharing mechanisms for protecting beneficiaries against unexpected health care costs, compensate the capital depreciation, increasing investments, and improve diseases prevention services and facilities in the provincial and national levels.

Changes of corneal biomechanics with keratoconus

PURPOSE: To perform advanced analysis of the corneal deformation response to air pressure in keratoconics compared with age- and sex-matched controls. METHODS: The ocular response analyzer was used to measure the air pressure-corneal deformation relationship of 37 patients with keratoconus and 37 age (mean 36 ± 10 years)- and sex-matched controls with healthy corneas. Four repeat air pressure-corneal deformation profiles were averaged, and 42 separate parameters relating to each element of the profiles were extracted. Corneal topography and pachymetry were performed with the Orbscan II. The severity of the keratoconus was graded based on a single metric derived from anterior corneal curvatures, difference in astigmatism in each meridian, anterior best-fit sphere, and posterior best-fit sphere. RESULTS: Most of the biomechanical characteristics of keratoconic eyes were significantly different from normal eyes (P <0.001), especially during the initial corneal applanation. With increasing keratoconus severity, the cornea was thinner (r = -0.407, P <0.001), the speed of corneal concave deformation past applanation was quicker (dive; r = -0.314, P = 0.01), and the tear film index was lower (r = -0.319, P = 0.01). The variance in keratoconus severity could be accounted for by the corneal curvature and central corneal thickness (r = 0.80) with biomechanical characteristics contributing an additional 4% (total r = 0.84). The area under the receiver operating characteristic curve was 0.919 ± 0.025 for keratometry alone, 0.965 ± 0.014 with the addition of pachymetry, and 0.972 ± 0.012 combined with ocular response analyzer biomechanical parameters. CONCLUSIONS: Characteristics of the air pressure-corneal deformation profile are more affected by keratoconus than the traditionally extracted corneal hysteresis and corneal resistance factors. These biomechanical metrics slightly improved the detection and severity prediction of keratoconus above traditional keratometric and pachymetric assessment of corneal shape.

Effect of uncorrected astigmatism on vision

PURPOSE: To examine the effect of uncorrected astigmatism in older adults. SETTING: University Vision Clinic METHOD: Twenty-one healthy presbyopes, aged 58.9±2.8 years, had astigmatism of 0.0 to -4.0 x 90?DC and -3.0DC of cylinder at 90?, 180? and 45? induced with spectacle lenses, with the mean spherical equivalent compensated to plano, in random order. Visual acuity was assessed binocularly using a computerised test chart at 95%, 50% and 10% contrast. Near acuity and reading speed were measured using standardised reading texts. Light scatter was quantified with the cQuant and driving reaction times with a computer simulator. Finally visual clarity of a mobile phone and computer screen was subjectively rated. RESULTS: Distance visual acuity decreased with increasing uncorrected astigmatic power (F=174.50, p<0.001) and was reduced at lower contrasts (F=170.77, p<0.001). Near visual acuity and reading speed also decreased with increasing uncorrected astigmatism power (p<0.001). Light scatter was not significantly affected by uncorrected astigmatism (p>0.05), but the reliability and variability of measurements decreased with increasing uncorrected astigmatic power (p<0.05). Driving simulator performance was also unaffected by uncorrected astigmatism (p>0.05), but subjective rating of clarity decreased with increasing uncorrected astigmatic power (p<0.001). Uncorrected astigmatism at 45? or 180? orientation resulted in a worse distance and near visual acuity, and subjective rated clarity than 90? orientation (p<0.05). CONCLUSION: Uncorrected astigmatism, even as low as 1.0DC, causes a significant burden on a patient’s vision. If left uncorrected, this could impact significantly on their independence, quality of life and wellbeing.

Evaluation of an open-field autorefractor's ability to measure refraction and hence potential to assess objective accommodation in pseudophakes

Background: To evaluate the accuracy of an open-field autorefractor compared with subjective refraction in pseudophakes and hence its ability to assess objective eye focus with intraocular lenses (IOLs). Methods: Objective refraction was measured at 6 m using the Shin-Nippon NVision-K 5001/Grand Seiko WR-5100K open-field autorefractor (five repeats) and by subjective refraction on 141 eyes implanted with a spherical (Softec1 n=53), aspherical (SoftecHD n=37) or accommodating (1CU n=22; Tetraflex n=29) IOL. Autorefraction was repeated 2 months later. Results: The autorefractor prescription was similar (average difference: 0.09±0.53 D; p=0.19) to that found by subjective refraction, with ~71% within ±0.50 D. The horizontal cylindrical components were similar (difference: 0.00±0.39 D; p=0.96), although the oblique (J45) autorefractor cylindrical vector was slightly more negative (by -0.06±0.25 D; p=0.06) than the subjective refraction. The results were similar for each of the IOL designs except for the spherical IOL, where the mean spherical equivalent difference between autorefraction and subjective was more hypermetropic than the Tetraflex accommodating IOL (F=2.77, p=0.04). The intrasession repeatability was

Development of a questionnaire to assess the relative subjective benefits of presbyopia correction

Purpose To develop a standardized questionnaire of near visual function and satisfaction to complement visual function evaluations of presbyopic corrections. Setting Eye Clinic, School of Life and Health Sciences, Aston University, Midland Eye Institute and Solihull Hospital, Birmingham, United Kingdom. Design Questionnaire development. Methods A preliminary 26-item questionnaire of previously used near visual function items was completed by patients with monofocal intraocular lenses (IOLs), multifocal IOLs, accommodating IOLs, multifocal contact lenses, or varifocal spectacles. Rasch analysis was used for item reduction, after which internal and test–retest reliabilities were determined. Construct validity was determined by correlating the resulting Near Activity Visual Questionnaire (NAVQ) scores with near visual acuity and critical print size (CPS), which was measured using the Minnesota Low Vision Reading Test chart. Discrimination ability was assessed through receiver-operating characteristic (ROC) curve analysis. Results One hundred fifty patients completed the questionnaire. Item reduction resulted in a 10-item NAVQ with excellent separation (2.92), internal consistency (Cronbach a = 0.95), and test–retest reliability (intraclass correlation coefficient = 0.72). Correlations of questionnaire scores with near visual acuity (r = 0.32) and CPS (r = 0.27) provided evidence of validity, and discrimination ability was excellent (area under ROC curve = 0.91). Conclusion Results show the NAVQ is a reliable, valid instrument that can be incorporated into the evaluation of presbyopic corrections.

A review of the surgical options for the correction of presbyopia

Presbyopia is an age-related eye condition where one of the signs is the reduction in the amplitude of accommodation, resulting in the loss of ability to change the eye's focus from far to near. It is the most common age-related ailments affecting everyone around their mid-40s. Methods for the correction of presbyopia include contact lens and spectacle options but the surgical correction of presbyopia still remains a significant challenge for refractive surgeons. Surgical strategies for dealing with presbyopia may be extraocular (corneal or scleral) or intraocular (removal and replacement of the crystalline lens or some type of treatment on the crystalline lens itself). There are however a number of limitations and considerations that have limited the widespread acceptance of surgical correction of presbyopia. Each surgical strategy presents its own unique set of advantages and disadvantages. For example, lens removal and replacement with an intraocular lens may not be preferable in a young patient with presbyopia without a refractive error. Similarly treatment on the crystalline lens may not be a suitable choice for a patient with early signs of cataract. This article is a review of the options available and those that are in development stages and are likely to be available in the near future for the surgical correction of presbyopia.

ICT and technical efficiency of the manufacturing industries in Iran

This paper extends the existing evidence on the relationship between Information and Communication Technology (ICT) and productivity using data from the entire Iranian manufacturing sector (22 industries) over the period 1993?1999. Estimates of efficiency using panel data confirm the positive and significant impact of ICT investments on productivity. Our finding is consistent with the most recent literatures in the context of developed and a few middle-income developing countries. Human capital and increasing ICT capital are probably two determining factors in gaining the positive payoffs from ICT investments in Iran.

Refractive outcomes of laser-assisted subepithelial keratectomy for myopia, hyperopia, and astigmatism using a 213 nm wavelength solid-state laser

To study the visual and refractive outcomes after laser-assisted subepithelial keratectomy (LASEK) performed with a 213 nm solid-state laser for a broad range of refractive errors.

Differential moderating effect of locus of control on effect of driving experience in young male and female drivers

Investigations of relationships between the specific personality variable, locus of control (LOC, Rotter, 1966) and driver behaviour or accidents have returned contrasting results. Review suggests dependence on gender or experience characteristics of participants, suggesting these factors interact with LOC to influence driving. Relationships were investigated in terms of influence on the eight driving styles of the Multidimensional Driving Style Inventory (MDSI, Taubman-Ben-Ari, Mikulincer & Gillarth, 2004) in young drivers (18-29 years). Gender and LOC differences in driving styles previously related to accidents were proposed. It was also proposed that driving experience influences driving style, and LOC influences effect of driving experience. Gender differences were found for dissociative, anxious, patient, risky, angry and high velocity styles. Women had more external LOC than men, and driver stress styles increased with more external LOC, but reduced with increased driving experience, but so did patient style. High velocity style increased with experience. Controlling for LOC revealed important gender differences in effect of experience: positive effects for men (reducing angry and high velocity, increasing carefulness) and negative effects for women (increasing angry and higher velocity, reducing carefulness). Findings suggest negative influence of high internal LOC on young men in terms of its interaction with experience.

Development of a near activity visual questionnaire to assess accommodating intraocular lenses

Purpose: To develop a questionnaire that subjectively assesses near visual function in patients with 'accommodating' intraocular lenses (IOLs). Methods: A literature search of existing vision-related quality-of-life instruments identified all questions relating to near visual tasks. Questions were combined if repeated in multiple instruments. Further relevant questions were added and item interpretation confirmed through multidisciplinary consultation and focus groups. A preliminary 19-item questionnaire was presented to 22 subjects at their 4-week visit post first eye phacoemulsification with 'accommodative' IOL implantation, and again 6 and 12 weeks post-operatively. Rasch Analysis, Frequency of Endorsement, and tests of normality (skew and kurtosis) were used to reduce the instrument. Cronbach's alpha and test-retest reliability (intraclass correlation coefficient, ICC) were determined for the final questionnaire. Construct validity was obtained by Pearson's product moment correlation (PPMC) of questionnaire scores to reading acuity (RA) and to Critical Print Size (CPS) reading speed. Criterion validity was obtained by receiver operating characteristic (ROC) curve analysis and dimensionality of the questionnaire was assessed by factor analysis. Results: Rasch Analysis eliminated nine items due to poor fit statistics. The final items have good separation (2.55), internal consistency (Cronbach's α = 0.97) and test-retest reliability (ICC = 0.66). PPMC of questionnaire scores with RA was 0.33, and with CPS reading speed was 0.08. Area under the ROC curve was 0.88 and Factor Analysis revealed one principal factor. Conclusion: The pilot data indicates the questionnaire to be internally consistent, reliable and a valid instrument that could be useful for assessing near visual function in patients with 'accommodating' IOLS. The questionnaire will now be expanded to include other types of presbyopic correction. © 2007 British Contact Lens Association.

Mechanism of action of the tetraflex accommodative intraocular lens

PURPOSE:To investigate the mechanism of action of the Tetraflex (Lenstec Kellen KH-3500) accommodative intraocular lens (IOL). METHODS:Thirteen eyes of eight patients implanted with the Tetraflex accommodating IOL for at least 2 years underwent assessment of their objective amplitude-of-accommodation by autorefraction, anterior chamber depth and pupil size with optical coherence tomography, and IOL flexure with aberrometry, each viewing a target at 0.0 to 4.00 diopters of accommodative demand. RESULTS:Pupil size decreased by 0.62+/-0.41 mm on increasing accommodative demand, but the Tetraflex IOL was relatively fixed in position within the eye. The ocular aberrations of the eye changed with increased accommodative demand, but not in a consistent manner among individuals. Those aberrations that appeared to be most affected were defocus, vertical primary and secondary astigmatism, vertical coma, horizontal and vertical primary and secondary trefoil, and spherical aberration. CONCLUSIONS:Some of the reported near vision benefits of the Tetraflex accommodating IOL appear to be due to changes in the optical aberrations because of the flexure of the IOL on accommodative effort rather than forward movement within the capsular bag.

Clinical evaluation of the Softec HD aberration-free aspheric intraocular lens

Purpose: To compare distance and near visual performance with a zero-aberration aspheric intraocular lens (IOL) (Softec HD, Lenstec, Inc. FL, USA) with that of an otherwise identical, but spherical IOL (Softec 1). Setting: Department of Ophthalmology, Solihull Hospital, West Midlands, United Kingdom. Methods: This prospective study comprised 37 patients with a Softec 1 spherical IOL implanted in one eye, who underwent phacoemulsification and received the Softec HD aspheric IOL in the fellow eye. One month post-operatively, unaided distance and near vision, residual refraction, best spectacle corrected distance and near visual acuity, reading speed, pseudoaccommodation and photopic contrast sensitivity were recorded. Wavefront analysis enabled comparison of higher order aberrations between the IOLs. Results: Prior to surgery, the Softec 1 and Softec HD eyes were not significantly different. Post-operatively, unaided vision, best spectacle corrected visual acuity and residual refraction were not significantly different between the eyes, nor were there significant differences observed between the measured wavefront aberrations. Once implanted, the range of focus was significantly better in the Softec HD IOL eye than the Softec 1 IOL eye and, although reading speed was equivalent to the Softec 1 eye, the print size at which this could be achieved was significantly smaller. Conclusions: Depth of field was significantly improved with the aspheric IOL compared with the spherical IOL, without any compromise in distance visual performance between the two IOLs.